WorldWideScience

Sample records for circuit water chemistry

  1. An Investigation into Water Chemistry in Primary Coolant Circuit of an Advanced Boiling Water Reactor

    International Nuclear Information System (INIS)

    To ensure operation safety, an optimization on the coolant chemistry in the primary coolant circuit of a nuclear reactor is essential no matter what type or generation the reactor belongs to. For a better understanding toward the water chemistry in an advanced boiling water reactor (ABWR), such as the one being constructed in the northern part of Taiwan, and for a safer operation of this ABWR, we conducted a proactive, thorough water chemistry analysis prior to the completion of this reactor in this study. A numerical simulation model for water chemistry analyses in ABWRs has been developed, based upon the core technology we established in the past. This core technology for water chemistry modeling is basically an integration of water radiolysis, thermal-hydraulics, and reactor physics. The model, by the name of DEMACE-ABWR, is an improved version of the original DEMACE model and was used for radiolysis and water chemistry prediction in the Longmen ABWR in Taiwan. Predicted results pertinent to the water chemistry variation and the corrosion behavior of structure materials in the primary coolant circuit of this ABWR under rated-power operation were reported in this paper. (authors)

  2. Secondary circuit water chemistry and related problems with SG

    International Nuclear Information System (INIS)

    Necessity for SG feed water and blowdown systems modernization Balakovo NPP steam generators PGV-1000M was identified at Units with VVER-1000 during commissioning separational, thermo-hydraulic and thermo-chemical testings. It was discovered, that in zone of 'hot' header coolant salt concentration (concentration of dissolved salts) was almost 2 times more, than salt concentration in blowdown water. A number of chemical testings was performed to investigate and optimize salts distribution in water volume of PGV-1000. (R.P.)

  3. A prototype expert system 'SMART' for water chemistry control in reactor water circuits

    International Nuclear Information System (INIS)

    The operational safety of a power plant depends mainly on the material compatibility of the system materials with the environment. However, for an operating plant, the material is almost fixed and hence one can improve the safety by controlling the surrounding environment. From the economy point of view, the plant availability factor as well as plant life extension (PLEX) are important considerations and these necessitate a systematic approach for continuous parametric monitoring, rapid data analysis and diagnosis for controlling the water chemistry regime. A prototype expert system 'SMART' was developed in BASIC language. The expert system consists of four modules. The DATA HANDLER module controls all the data handling functions and graphical display of the data parameters. It also generates weekly and monthly reports of the water chemistry data. The DATA INTERPRETER module compares the experimental data with the theoretically calculated values and predicts the presence of impurity ingress in the system. The CHEMISTRY EXPERT contains the knowledge base about the various sub-systems. All the water chemistry specifications are translated in the form of IF... THEN.. rules and are stored in this module. The expert system inferences with the forward chain reasoning mechanism to identify the diagnostic parameters by consulting the knowledge base and applying the appropriate rules. The ACTION EXPERT module collects all the diagnostic parameters and suggests the operator, the remedial actions/counter measures that should be taken immediately. This rule based system can be expanded to accommodate different water chemistry regimes. (author)

  4. Water chemistry and corrosion control of cladding and primary circuit components. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    Corrosion is the principal life limiting degradation mechanism in nuclear steam supply systems, especially taking into account the trends to increase fuel burnup, thermal rate and cycle length. Primary circuit components of water cooled power reactors have an impact on Zr-based alloys behaviour due to crud (primary circuit corrosion products) formation, transport and deposition on heat transfer surfaces. Crud deposits influence water chemistry, radiation and thermal hydraulic conditions near cladding surface, and by this way-Zr-based alloy corrosion. During the last decade, significant improvements were achieved in the reduction of the corrosion and dose rates by changing the cladding material for one more resistant to corrosion or by the improvement of water chemistry conditions. However, taking into account the above mentioned tendency for heavier fuel duties, corrosion and water chemistry, control will remain a serious task to work with for nuclear power plant operators and scientists, as well as development of generally accepted corrosion model of Zr-based alloys in a water environment in a new millennium. Upon the recommendation of the International Working Group on Water Reactor Fuel Performance and Technology, water chemistry and corrosion of cladding and primary circuit components are in the focus of the IAEA activities in the area of fuel technology and performance. At present the IAEA performs two co-ordinated research projects (CRPs): on On-line High Temperature Monitoring of Water Chemistry and Corrosion (WACOL) and on Activity Transport in Primary Circuits. Two CRPs deal with hydrogen and hydride degradation of the Zr-based alloys. A state-of-the-art review entitled: 'Waterside Corrosion of Zirconium Alloys in Nuclear Power Plants' was published in 1998. Technical Committee meetings on the subject were held in 1985 (Cadarache, France), 1989 (Portland, USA), 1993 (Rez, Czech Republic). During the last few years extensive exchange of experience in

  5. Water chemistry of secondary circuit and SG currently status NPP 'Kozloduy' 3

    International Nuclear Information System (INIS)

    The author gives a historical review of the secondary water chemistry regimes of NPP Kozloduy Unit 3. Results of eddy current inspection on the steam generator of Unit 5 and quantity of the deposits on the surfaces of steam generator during 1989-2001 inspections are given. (uke)

  6. Water chemistry used in the secondary coolant circuit of unit 3 at the rovno nuclear power station involving correction treatment of working medium with lithium hydroxide and ethanolamine

    Science.gov (United States)

    Kozlov, V. Ya.; Vlasenko, N. I.; Kozlova, T. Yu.

    2011-03-01

    The all-volatile water chemistry used in the secondary coolant circuit involving correction treatment of the steam generator's boiler water with lithium hydroxide and the ethanolamine water chemistry are analyzed from the viewpoint of their effect on the erosion-corrosion wear of equipment used in the secondary coolant system and damageability of heat-transfer tubes used in PGV-1000M steam generators.

  7. Impact of load follow operation on the chemistry of the primary and secondary circuit of a pressurized water reactor

    International Nuclear Information System (INIS)

    Germany decided to abandon nuclear energy and to switch to renewable energy forms. According the renewable energy act renewable energy forms have priority to be fed to the grid. The support of wind and solar energy demands more and more load follow operation of the remaining nuclear power plants to stabilize the grid. This report summarizes first experience with load follow operation in two pressurized water reactors (Philippsburg KKP2 and Neckarwestheim GKNI) with regard to chemistry and radiology. The most important mechanisms of dose rate built up on the primary side are described with Co-60 and Co-58 being the main contributors to dose rate. Goal of the primary side chemistry is to avoid or at least to delay the dose rate built-up as far as achievable. Both reactors are operated according to the modified coordinated B-Li-Chemistry with a pH300 of 7.4 as target value for optimised dose build up delay. By using B-10-enriched boric acid with a boron-10 abundance of 30 at-% (compared to ca. 19.9 at-% in natural boron) the pH300 target value can be reached earlier in the cycle due to the lower concentration of boric acid required for neutron balancing. In GKNI Zn-injection was started 2005 as a mean of dose reduction. Since 2007 GKNI was operated with load follow operation. In KKP2 load reductions due to wind energy excess are more and more common since 2008. The results of dose rate measurements on the primary side are correlated to primary coolant chemistry and load follow operation. The use of enriched boric acid had a positive (i.e. reducing dose rate) impact on the activity build-up of Co-60 on the loop lines, thus proving the effectiveness of the VGB specifications. After 5 years (one half life time of Co-60) of Zn-injection a positive effect on surface occupancy with nuclides can be determined. The impact of short term deviations from optimal chemical conditions during load follow operation on the activity build up is assessed on the basis of the corrosion

  8. Chemistry of the secondary circuit

    International Nuclear Information System (INIS)

    Study of the various possibilities to prevent the corrosion phenomena in the different parts of the secondary circuit (condenser, water facility, steam lines, turbines and vapor generators): choice of a volatile conditioning with ammonia or morpholine and not with phosphate which concentration in the vapor generators may induce local corrosion, and search for a low oxidizing medium by restriction of the air admission and addition of hydrazine

  9. Fission product chemistry and aerosol behaviour in the primary circuit of a pressurised water reactor under severe accident conditions

    International Nuclear Information System (INIS)

    Three key accident sequences are considered covering a representative range of different environments of pressure, flow, temperature history and degree of zircaloy oxidation, and their principle thermal hydraulic and physical characteristics affecting chemistry behaviour are identified. Inventories, chemical forms and timing of fission product release are summarized together with the major sources of structural materials and their release characteristics. Chemistry of each main fission product species is reviewed from available experimental and/or theoretical data. Studies modelling primary circuit fission product behaviour are reviewed. Requirements for further study are assessed. (UK)

  10. Secondary Circuit Start Up Chemistry Optimisation

    International Nuclear Information System (INIS)

    In a context of investment and renewal of equipment, Electricite De France (EDF) put enhanced efforts on operating practices during start-up of the secondary circuit, in order to improve operational performance and materials lifetime. This article focuses on the objective of optimizing the filling, the chemical conditioning and the thermal conditioning of the secondary fluid, while taking into account the following issues: - Limiting the time required to obtain a proper chemistry, - Limiting the amount of water and steam used, - Limiting the amount of effluent generated. The scope is all start-up conditions of secondary circuit, both after refuelling outage or fortuitous shutdowns of the plant. The recommendations produced are based on existing local procedures and good practices, which were collected and developed in order to propose a generic methodology understandable and useful both for operators, chemists and managers. (authors)

  11. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  12. Conducting water chemistry of the secondary coolant circuit of VVER-based nuclear power plant units constructed without using copper containing alloys

    Science.gov (United States)

    Tyapkov, V. F.

    2014-07-01

    The secondary coolant circuit water chemistry with metering amines began to be put in use in Russia in 2005, and all nuclear power plant units equipped with VVER-1000 reactors have been shifted to operate with this water chemistry for the past seven years. Owing to the use of water chemistry with metering amines, the amount of products from corrosion of structural materials entering into the volume of steam generators has been reduced, and the flow-accelerated corrosion rate of pipelines and equipment has been slowed down. The article presents data on conducting water chemistry in nuclear power plant units with VVER-1000 reactors for the secondary coolant system equipment made without using copper-containing alloys. Statistical data are presented on conducting ammonia-morpholine and ammonia-ethanolamine water chemistries in new-generation operating power units with VVER-1000 reactors with an increased level of pH. The values of cooling water leaks in turbine condensers the tube system of which is made of stainless steel or titanium alloy are given.

  13. Water quality control program in experimental circuits

    International Nuclear Information System (INIS)

    The Water Quality Control Program of the Experimental Circuits visualizes studying the water chemistry of the cooling in the primary and secondary circuits, monitoring the corrosion of the systems and studying the mechanism of the corrosion products transport in the systems. (author)

  14. Assessment of effectiveness of the water chemistry in secondary circuits of WWER-440 units of Kozloduj nuclear power plant

    International Nuclear Information System (INIS)

    The increasing concentration of corrosion products in the turbine condensate and feedwater was measured during the operation of the Kozloduj-1 reactor. Addition of hydrazine to the turbine condensate brought about decrease in the concentrations of copper and iron in feedwater and increase in the feedwater pH value. Based on these data, it was decided to alter the chemistry of units 1 through 3 of the Kozloduj nuclear power plant by adding hydrazine to the turbine condensate in amounts exceeding 150 μg/kg and by increasing the feedwater pH to 8.6±0.3. Experimental investigation of unit 4 revealed that the concentration of copper in feedwater approached the highest permissible value and that the concentration of iron was comparable to that observed at units 1-3. The concentration of corrosion products increased during the fueling cycle. Therefore, it was decided to add hydrazine to the condensate in amounts of 100-150 μg/kg. This hydrazine chemistry brought about suppression of corrosion of copper alloys used in the secondary circuit and reduction in the corrosion of surfaces within the circuit. (E.J.). 3 figs., 1 tab., 7 refs

  15. Introduction of water chemistry conditions of the secondary coolant circuit with metering organic amines at nuclear power stations equipped with VVER-1000 reactors

    Science.gov (United States)

    Tyapkov, V. F.; Erpyleva, S. F.; Bykova, V. V.

    2009-05-01

    Results from introduction of new water chemistry conditions involving metering of organic amines (morpholine and ethanolamine) at nuclear power stations equipped with VVER-1000 reactors are presented.

  16. Chemistry in water reactors

    International Nuclear Information System (INIS)

    The international conference Chemistry in Water Reactors was arranged in Nice 24-27/04/1994 by the French Nuclear Energy Society. Examples of technical program areas were primary chemistry, operational experience, fundamental studies and new technology. Furthermore there were sessions about radiation field build-up, hydrogen chemistry, electro-chemistry, condensate polishing, decontamination and chemical cleaning. The conference gave the impression that there are some areas that are going to be more important than others during the next few years to come. Cladding integrity: Professor Ishigure from Japan emphasized that cladding integrity is a subject of great concern, especially with respect to waterside corrosion, deposition and release of crud. Chemistry control: The control of the iron/nickel concentration quotient seems to be not as important as previously considered. The future operation of a nuclear power plant is going to require a better control of the water chemistry than achievable today. One example of this is solubility control via regulation in BWR. Trends in USA: means an increasing use of hydrogen, minimization of SCC/IASCC, minimization of radiation fields by thorough chemistry control, guarding fuel integrity by minimization of cladding corrosion and minimization of flow assisted corrosion. Stellite replacement: The search for replacement materials will continue. Secondary side crevice chemistry: Modeling and practical studies are required to increase knowledge about the crevice chemistry and how it develops under plant operation conditions. Inhibitors: Inhibitors for IGSCC and IGA as well for the primary- (zinc) as for the secondary side (Ti) should be studied. The effects and mode of operation of the inhibitors should be documented. Chemical cleaning: of heat transfer surfaces will be an important subject. Prophylactic cleaning at regular intervals could be one mode of operation

  17. Crevice chemistry estimation from bulk water chemistry

    International Nuclear Information System (INIS)

    Since the first PWR plant in Japan started commercial operation in 1970, 22 plants are running in Japan as of the end of 1994. The main purpose of secondary water chemistry control is to minimize the corrosion possibility of the secondary system equipment, especially steam generators (SG). To achieve this objective, much effort has been concentrated on improving secondary water chemistry control. As a result of this effort, the recent secondary water chemistry in Japanese plants is well maintained in every stage of operation. However, to ensure and improve the reliability of SG, it is necessary to control crevice environments, which are located at tube/tube support plate intersections and under the sludge pile on the tube sheet. According to recent crevice monitoring examination results, the concentration behavior impurities in SG bulk water at the crevice is different for each species, and SG bulk water and crevice chemical compositions are not always equal. From these results, to control the crevice chemistry, improving bulk water chemistry control methods and a new type of molar ratio control index is needed. This paper introduces a brief summary of a recent crevice chemistry evaluation technique and bulk water chemistry control method, which is employed for crevice chemistry control, based on crevice monitoring examination results

  18. The effect of hydrazine dosing on high temperature water chemistry and corrosion product transport in primary circuit of VVER 440 units

    International Nuclear Information System (INIS)

    Some of the VVER 440 type reactors have started to use hydrazine dosing to primary coolant instead of ammonia, because it has been shown to be efficient in reducing activity transport. On the other hand, some other studies have shown that there is no significant difference between new VVER units using hydrazine dosing and the ones operating with standard potassium/ammonia water chemistry. In this paper the results are presented concerning the out-of-core high temperature water chemistry and in-core redox potential measurements at Rez research reactor in Czech republic during hydrazine/ammonia water chemistries. At Loviisa 1 unit (VVER 440) in Finland the pHT and redox potentials were monitored during standard potassium hydroxide/ammonia operation. (authors). 5 figs., 13 refs

  19. Pore-water chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Vinsot, A. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Appelo, C.A.J. [Valeriusstraat 11, Amsterdam (Netherlands); Cailteau, C. [LEM, ENSG/INPL, 54 - Vandoeuvre-les-Nancy (France); Cailteau, C. [G2R-CREGU, UMR 7566 CNRS, 54 - Vandoeuvre-les-Nancy (France); Cailteau, C. [Andra - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Mettler, S.; Wersin, P. [NAGRA, CH-5430 Wettingen (Switzerland); Canniere, P. de [Studiecentrum voor Kernenergie - Centre d' Etude de l' Energie Nucleaire, Mol (Belgium); Gabler, H.E. [BGR, Hannover (Germany); Gaucher, E.C.; Tournassat, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Jacquot, E.; Altmann, S. [Agence Nationale pour la Gestion des Dechets Radioactifs (DS/TR), 92 - Chatenay Malabry (France); Vinsot, A. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Recherche Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Courdouan, A.; Christl, I.; Kretzschmar, R. [Institute of Biogeochemistry and Pollutant Dynamics, Dept. of Environmental Sciences, ETH Zurich, CHN (Switzerland); Wersin, P. [National Cooperative for the Disposal of Radioactive Waste (Nagra), Wettingen (Switzerland); Savoye, S.; Matray, J.M.; Wittebroodt, Ch.; Cabrera, J.; Bensenouci, F. [Institut de Radioprotection et de Surete Nucleaire, 92 - Fontenay aux Roses (France); Michelot, J.L.; Bensenouci, F. [Paris-11 Univ., UMR IDES CNRS, 91 - Orsay (France); Waber, H.S. [Rock-Water Interaction (RWI), Inst. of Geological Sciences, Bern (Switzerland); Wittebroodt, Ch. [Montpellier-2 Univ., MSE, 34 (France); Lavielle, B.; Gilabert, E.; Thomas, B.; Lavastre, V. [Bordeaux 1-2 Univ., (GdR FORPRO 0788), Chimie Nucleaire Analytique et Bioenvironnementale (CNAB), CNRS, 33 - Gradignan (France); Lavastre, V. [Nimes Univ., Geochimie Isotopique Environnementale (GIS/CEREGE), CNRS-RANCE, 30 (France)

    2007-07-01

    This session gathers 5 articles dealing with: CO{sub 2} data on gas and pore water sampled in-situ in the Opalinus clay at the Mont Terri rock laboratory (A. Vinsot, C.A.J. Appelo, C. Cailteau, S. Mettler, P. Wersin, P. De Canniere, H.E. Gaebler); the improvements in the modelling of the pore water chemistry of the Callovo-Oxfordian formation (E.C. Gaucher, C. Tournassat, E. Jacquot, S. Altmann, A. Vinsot) the nature and reactivity of dissolved organic matter in the Opalinus clay and Callovo-Oxfordian formations (A. Courdouan, I. Christl, P.Wersin, R. Kretzschmar); PH4: a 250 m deep borehole in Tournemire for assessing the reliability of chloride, helium and water stable isotopes profiles in the Toarcian/ Domerian shales (S. Savoye, J.L. Michelot, H.N. Waber, J.M. Matray, F. Bensenouci, Ch. Wittebroodt, J. Cabrera); and the development of a new facility for dating old groundwaters by using {sup 81}Kr (B. Lavielle, E. Gilabert, B. Thomas, V. Lavastre)

  20. Prevention of serious impurity penetration into water-steam circuits

    International Nuclear Information System (INIS)

    In consequence of reports from several power Plants concerning heavy damages due to penetrations of impurities into the water-steam circuit, the VGB Sub-Committee 'Water Chemistry in Thermal Power Plants' has established a working group to check-up how serious impurity penetration can be avoided. The lecture describes possible danger points. Suitable technical arrangements for the avoidance of penetrations, and possibilities for monitoring will be discussed. Penetration of impurities cannot be avoided with absolute reliability, even when the recommended arrangements and usual monitoring are realized. Additional measures for the protection of water steam circuits will be suggested. (orig.)

  1. Safety aspects of water chemistry in light water reactors

    International Nuclear Information System (INIS)

    The goals of the water chemistry control programmes are to maximize operational safety and the availability and operating life of primary system components, to maximize fuel integrity, and to control radiation buildup. To achieve these goals an effective corporate policy should be developed and implemented. Essential management responsibilities are: Recognizing of the long-term benefits of avoiding or minimizing: a) system corrosion; b) fuel failure; and c) radiation buildup. The following control or diagnostic parameters are suitable performance indicators: for PWR primary coolant circuits: pH of reactor water (by operating temperature); Concentration of chlorides in reactor water; Hydrogen (or oxygen) in reactor water. For PWR secondary coolant circuits: pH in feedwater; Cation productivity in steam generator blowdown; Iron concentration in feedwater; Oxygen concentration in condensate. And BWR coolant circuits: Conductivity of reactor water; Concentration of chlorides in reactor water; Iron concentration in feedwater; Copper concentration in feedwater. The present document represents a review of the developments in some Member States on how to implement a reasonable water chemistry programme and how to assess its effectiveness through numerical indicators. 12 figs, 20 tabs

  2. Water chemistry and poultry processing water quality

    Science.gov (United States)

    This study examined the influences of water chemistry on the quality of process water used in immersion chillers. During commercial poultry processing the bird carcasses come in direct contact with process water during washing and chilling operations. Contamination of the process water with bacteria...

  3. Advances in BWR water chemistry

    International Nuclear Information System (INIS)

    This paper reviews recent advances in Boiling Water Reactor (BWR) water chemistry control with examples of plant experiences at U.S. designed BWRs. Water chemistry advances provide some of the most effective methods for mitigating materials degradation, reducing fuel performance concerns and lowering radiation fields. Mitigation of stress corrosion cracking (SCC) of materials remains a high priority and improved techniques that have been demonstrated in BWRs will be reviewed, specifically hydrogen injection combined with noble metal chemical addition (NMCA) and the newer on-line noble metal application process (OLNC). Hydrogen injection performance, an important part of SCC mitigation, will also be reviewed for the BWR fleet, highlighting system improvements that have enabled earlier injection of hydrogen including the potential for hydrogen injection during plant startup. Water chemistry has been significantly improved by the application of pre-filtration and optimized use of ion exchange resins in the CP (condensate polishing) and reactor water cleanup (RWCU) systems. EPRI has monitored and supported water treatment improvements to meet water chemistry goals as outlined in the EPRI BWR Water Chemistry Guidelines, particularly those for SCC mitigation of reactor internals and piping, minimization of fuel risk due to corrosion and crud deposits and chemistry control for radiation field reduction. In recent years, a significant reduction has occurred in feedwater corrosion product input, particularly iron. A large percentage of plants are now reporting <0.1 ppb feedwater iron. The impacts to plant operation and chemistry of lower feedwater iron will be explored. Depleted zinc addition is widely practiced across the fleet and the enhanced focus on radiation reduction continues to emphasize the importance of controlling radiation source term. In addition, shutdown chemistry control is necessary to avoid excessive release of activated corrosion products from fuel

  4. Experience on KKNPP VVER 1000 MWe water chemistry

    International Nuclear Information System (INIS)

    Kudankulam Nuclear Power Project consists of pressurized water reactor (VVER) 2 x 1000 MWe constructed in collaboration with Russian Federation at Kudankulam in Tirunelveli District, Tamilnadu. Unit - 1 attained criticality on July 13th 2013 and the unit was synchronized to grid on 22nd October 2013. This paper highlights experience gained on water chemistry regime for primary and secondary circuit. (author)

  5. Quantum chemistry and charge transport in biomolecules with superconducting circuits

    Science.gov (United States)

    García-Álvarez, L.; Las Heras, U.; Mezzacapo, A.; Sanz, M.; Solano, E.; Lamata, L.

    2016-06-01

    We propose an efficient protocol for digital quantum simulation of quantum chemistry problems and enhanced digital-analog quantum simulation of transport phenomena in biomolecules with superconducting circuits. Along these lines, we optimally digitize fermionic models of molecular structure with single-qubit and two-qubit gates, by means of Trotter-Suzuki decomposition and Jordan-Wigner transformation. Furthermore, we address the modelling of system-environment interactions of biomolecules involving bosonic degrees of freedom with a digital-analog approach. Finally, we consider gate-truncated quantum algorithms to allow the study of environmental effects.

  6. Quantum chemistry and charge transport in biomolecules with superconducting circuits

    Science.gov (United States)

    García-Álvarez, L.; Las Heras, U.; Mezzacapo, A.; Sanz, M.; Solano, E.; Lamata, L.

    2016-01-01

    We propose an efficient protocol for digital quantum simulation of quantum chemistry problems and enhanced digital-analog quantum simulation of transport phenomena in biomolecules with superconducting circuits. Along these lines, we optimally digitize fermionic models of molecular structure with single-qubit and two-qubit gates, by means of Trotter-Suzuki decomposition and Jordan-Wigner transformation. Furthermore, we address the modelling of system-environment interactions of biomolecules involving bosonic degrees of freedom with a digital-analog approach. Finally, we consider gate-truncated quantum algorithms to allow the study of environmental effects. PMID:27324814

  7. A handbook of nuclear water chemistry

    International Nuclear Information System (INIS)

    This contents is divided three parts. The first part deals with chemistry which is related water nuclear energy. So it explains the role of water in atomic reactor including the basic properties of water, the oxide chemistry electricity chemistry, radiochemistry and measuring techniques of the quality of water in nuclear plant and radiation. The second part introduces technique of nuclear water chemistry, which explains purpose, definition and speciality of water chemistry in light-water reactor. The third part indicates application technology of water chemistry in nuclear energy including putting zinc in light-water reactor and technology of surveillance of leakage in steam generator.

  8. BWR water chemistry impurity studies

    International Nuclear Information System (INIS)

    Laboratory studies were made on the effect of water impurities on environmental cracking in simulated BWR water of stainless steel, low alloy steel and nickel-base alloys. Constant elongation rate tensile (CERT) tests were run in simulated normal water chemistry (NWC), hydrogen water chemistry (HWC), or start-up environment. Sulfate, chloride and copper with chloride added to the water at levels of a fraction of a ppM were found to be extremely deleterious to all kinds of materials except Type 316 NG. Other detrimental impurities were fluoride, silica and some organic acids, although acetic acid was beneficial. Nitrate and carbon dioxide were fairly inoccuous. Corrosion fatigue and constant load tests on compact tension specimens were run in simulated normal BWR water chemistry (NWC) or hydrogen water chemistry (HWC), without impurities or with added sulfate or carbon dioxide. For sensitized Type 304 SS in NWC, 0.1 ppM sulfate increased crack propagation rates in constant load tests by up to a factor of 100, and in fatigue tests up to a factor of 10. Also, cracking in Type 316 nuclear grade SS and Alloy 600 was enhanced, but to a smaller degree. Carbon dioxide was less detrimental than sulfate. 3 figs., 4 tabs

  9. Collection of theses of 7th International scientific and technical conference Water chemistry of NPP

    International Nuclear Information System (INIS)

    Collection of theses of the 7th International scientific and technical conference Water chemistry of NPP taking place in Moscow, 17-19 October 2006, is presented. The collection involves theses of reports on wide frame concerning water chemistry of NPP. Administration of the water chemistry of NPP basic circuits with different types of reactors, reliability of facility operation and radiation situation, possible ways for technological development of the water chemistry of NPP are analyzed. Experience of operation and ways for improvements in water purification as well as main problems and directions of the development of water chemistry control of NPP are discussed

  10. PWR secondary water chemistry guidelines: Revision 3

    International Nuclear Information System (INIS)

    An effective, state-of-the art secondary water chemistry control program is essential to maximize the availability and operating life of major PWR components. Furthermore, the costs related to maintaining secondary water chemistry will likely be less than the repair or replacement of steam generators or large turbine rotors, with resulting outages taken into account. The revised PWR secondary water chemistry guidelines in this report represent the latest field and laboratory data on steam generator corrosion phenomena. This document supersedes Interim PWR Secondary Water Chemistry Recommendations for IGA/SCC Control (EPRI report TR-101230) as well as PWR Secondary Water Chemistry Guidelines--Revision 2 (NP-6239)

  11. Recent developments in BWR water chemistry

    International Nuclear Information System (INIS)

    Water chemistry is of critical importance to the operation and economic viability of the Boiling Water Reactor (BWR). A successful water chemistry program will satisfy the following goals: - Minimize the incidence and growth of SCC/IASCC, - Minimize plant radiation fields controllable by chemistry, -Maintain fuel integrity by minimizing cladding corrosion, - Minimize flow-accelerated corrosion (FAC) in balance-of-plant components. The impact of water chemistry on each of these goals is discussed in more detail in this paper. It should be noted that water chemistry programs also include surveillance and operating limits for other plant water systems (e.g., service water, closed cooling water systems, etc.) but these are out of the scope of this paper. This paper reviews developments in water chemistry guidelines for U.S. BWR nuclear power plants. (author). 2 figs., 2 tabs., 7 refs

  12. Boom clay pore water chemistry

    International Nuclear Information System (INIS)

    In Belgium, geological disposal in clay is the primary option for the isolation of high-level radioactive waste and spent fuel from the biosphere. The Boom Clay is studied as the potential host rock for methodological studies on the geological disposal of radioactive waste. It is present under the facilities of the SCK-CEN at Mol, at a depth of 190 to 293 m. The current R and D programme focuses on the feasibility and safety of radioactive waste disposal in the Boom Clay. In this framework, a detailed characterisation of the clay is performed (mechanical, physico-chemical and hydrogeological properties, variability, role of organic matter,...). In addition, high priority is given to the understanding of the basic phenomena which control the retention o f radionuclides in the clay. Therefore, it is very important to characterise and understand the pore water composition in the host rock. All the available information from previous studies on the Boom Clay pore water chemistry was synthesise d in a 'state of the art' report, status 2004. This report describes the pore water sampling and analytical techniques, the results, and interpretation of a series of studies carried out in-situ in the HADES URF and in the laboratories. The objective of this study was to evaluate the most reliable technique(s) to obtain representative pore water samples, to determine the variation of the pore water composition in the Boom Clay, to present a coherent geochemical model for explaining the mechanisms controlling the Boom Clay pore water composition, and to propose a reference pore water composition to be used in the laboratory experiments, for speciation calculations, and for assessments of perturbation that might influence the Boom Clay pore water. The main conclusions will be presented here. (authors)

  13. COST : action chemistry conference on supramolecular chemistry in water

    OpenAIRE

    Magri, David C.

    2014-01-01

    Scientists and chemists from 18 countries gathered in Malta for the 3rd Scientific Meeting on Supramolecular Chemistry in Water between the 9 − 11th of November 2013 at the Old University Building on St Paul Street in Valletta

  14. Water chemistry of Atucha II PHWVR. Design concepts and evolution

    International Nuclear Information System (INIS)

    Full text: Atucha II is a pressurized heavy water vessel reactor designed by Siemens-KWU, currently part of AREVA NP, of 745 MWe and similar to Atucha I, which has been in operation over 25 years. The primary heat transport system (PHTS) is composed by vertical channels (277-313 C degrees) that allocate the fuel elements while the moderator circuit is composed by a partially separated circuit (142-173 C degrees). The moderation power is transferred to the feedwater through the moderator heat exchangers (HX). These HXs operate as the last, high pressure water-steam cycle heaters as well. Materials (with exception of fuel channels and fuel sheaths which are made of zirconium alloys) are all austenitic steels while cobalt containing alloys have been all replaced at the design stage. Steam generator and moderator HX tubing are Alloy 800 made. The core is operated without boron except with the first fresh nucleus. The secondary circuit or Balance of plant (BOP) is similar in conception to that of a PWR but the moderator HXs. It is entirely built of ferrous alloys, has a feedwater-deaerator tank and moisture separator. The energy sink is the Rio de la Plata River. The Reactors Chemistry Department, Chemistry Division, National Atomic Energy Commission, in its character of R and D institution has been committed by CNA II-N.A.S.A Project to prepare the water chemistry specifications, water chemistry engineering and manuals, considering the type of reactor, design and construction aspects and operation characteristics, taking into account the current state-of-the art and worldwide standards. This includes conceptual aspects and implementation and operative aspects as well. This documentation will be released after a designer's review as it has been stated in the respective agreement. Respecting the confidentiality agreement between CNEA and NASA and the confidentiality regarding handling original documentation provided by the designer, it is considered illustrative to

  15. Green chemistry oriented organic synthesis in water.

    Science.gov (United States)

    Simon, Marc-Olivier; Li, Chao-Jun

    2012-02-21

    The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective. PMID:22048162

  16. Water chemistry experiences with VVERs at Kudankulam

    International Nuclear Information System (INIS)

    Kudankulam Nuclear Power Project - 1 and 2 (Kudankulam NPP - 1 and 2) are pressurised water cooled VVERs of 1000 MWe each. Kudankulam NPP Unit - 1 is presently on its first cycle of operation and Kudankulam NPP Unit - 2 is on the advanced stage of commissioning with the successful completion of hot run related Functional tests. Water Chemistry aspects during various phases of commissioning of Kudankulam NPP Unit - 1 such as Hot Run, Boric acid flushing, initial fuel Loading (IFL), First approach to Criticality (FAC) are discussed. The main objectives of the use of controlled primary water chemistry programme during the hot functional tests are reviewed. The importance of the relevant water chemistry parameters were ensured to have the quality of the passive layer formed on the primary coolant system surfaces. The operational experiences during the 1st cycle of operation of primary water chemistry, radioactivity transport and build-up are presented. The operational experience of some VVER units in the field of the primary water chemistry, radioactivity transport and build-up are presented as a comparison to VVER at Kudankulam NPP. The effects of the initial passivated layer formed on metal surfaces during hot run, activated corrosion products levels in the primary coolant under controlled water chemistry regime and the contamination/radiation situation are discussed. This report also includes the water chemistry related issues of secondary water systems. (author)

  17. Perspective: Water cluster mediated atmospheric chemistry

    International Nuclear Information System (INIS)

    The importance of water in atmospheric and environmental chemistry initiated recent studies with results documenting catalysis, suppression and anti-catalysis of thermal and photochemical reactions due to hydrogen bonding of reagents with water. Water, even one water molecule in binary complexes, has been shown by quantum chemistry to stabilize the transition state and lower its energy. However, new results underscore the need to evaluate the relative competing rates between reaction and dissipation to elucidate the role of water in chemistry. Water clusters have been used successfully as models for reactions in gas-phase, in aqueous condensed phases and at aqueous surfaces. Opportunities for experimental and theoretical chemical physics to make fundamental new discoveries abound. Work in this field is timely given the importance of water in atmospheric and environmental chemistry.

  18. Areva's water chemistry guidebook with chemistry guidelines for next generation plants (AREVA EPRTM reactors)

    International Nuclear Information System (INIS)

    Over the years, AREVA globally has maintained a strong expertise in LWR water chemistry and has been focused on minimizing short-term and long-term detrimental effects of chemistry for startup, operation and shutdown chemistry for all key plant components (material integrity and reliability, promote optimal thermal performances, etc.) and fuel. Also AREVA is focused on minimizing contamination and equipment/plant dose rates. Current Industry Guidelines (EPRI, VGB, etc.) provide utilities with selected chemistry guidance for the current operating fleet. With the next generation of PWR plants (e.g. AREVA's EPRTM reactor), materials of construction and design have been optimized based on industry lessons learned over the last 50+ years. To support the next generation design, AREVA water chemistry experts, have subsequently developed a Chemistry Guidebook with chemistry guidelines based on an analysis of the current international practices, plant operating experience, R and D data and calculation codes now available and/or developed by AREVA. The AREVA LWR chemistry Guidebook can be used to help resolve utility and safety authority questions and addresses regulation requirement questions/issues for next generation plants. The Chemistry Guidebook provides water chemistry guidelines for primary coolant, secondary side circuit and auxiliary systems during startup, normal operation and shutdown conditions. It also includes conditioning and impurity limits, along with monitoring locations and frequency requirements. The Chemistry Guidebook Guidelines will be used as a design reference for AREVA's next generation plants (e.g. EPRTM reactor). (authors)

  19. Fog water chemistry in Shanghai

    Science.gov (United States)

    Li, Pengfei; Li, Xiang; Yang, Chenyu; Wang, Xinjun; Chen, Jianmin; Collett, Jeffrey L., Jr.

    2011-08-01

    With the aim of understanding the fog chemistry in a Chinese megacity, twenty-six fog water samples were collected in urban Shanghai from March 2009 to March 2010. The following parameters were measured: pH, electrical conductivity (EC), ten inorganic major ions ( SO42-, NO3-, NO2-, F -, Cl -, Na +, K +, Ca 2+, Mg 2+, NH4+) and four major organic acids (CH 3COO -, HCOO -, CO42-, MSA). The total ionic concentration (TIC) and EC of fog samples were one or two orders of magnitude higher than those often found in Europe, North America and other Asian countries. Pollutants were expected to be mainly from local sources, including factories, motor vehicle emissions and civil construction. Non-local sources such as moderate- and long-range transport of sea salt also contributed to pollution levels in fog events as indicated by back trajectory analysis. The pH of the fog water collected during the monitoring period varied from 4.68 to 6.58; acidic fogs represented about 30.8% of the total fog events during this period. The fog water was characterized by high concentrations of SO42- (20.0% of measured TIC), NO3- (17.1%), NH4+ (28.3%) and Ca 2+ (14.4%). SO42- and NO3-, the main precursors of fog acidity, were related to burning fossil fuels and vehicle emissions, respectively. NH4+, originating from the scavenging of gaseous ammonia and particulate ammonium nitrate and ammonium sulfate, and Ca 2+, originating from the scavenging of coarse particles, acted as acid neutralizers and were the main cause for the relatively high pH of fogs in Shanghai. The ratio of ( SO42- + NO3-)/( NH4+ + Ca 2+) was lower than 1, indicating the alkaline nature of the fog water. A high ratio of NO3-/ SO42- and low ratio of HCOO -/CH 3COO - were consistent with large contributions from vehicular emissions that produce severe air pollution in megacities.

  20. BWR Water Chemistry Guidelines: 1993 Revision, Normal and hydrogen water chemistry

    International Nuclear Information System (INIS)

    The goal of water chemistry control is to extend the operating life of the reactor and rector coolant system, balance-of-plant components, and turbines while simultaneously controlling costs to safeguard the continued economic viability of the nuclear power generation investment. To further this goal an industry committee of chemistry personnel prepared guidelines to identify the benefits, risks, and costs associated with water chemistry in BWRs and to provide a template for an optimized water chemistry program. This document replaces the BWR Normal Water Chemistry Guidelines - 1986 Revision and the BWR Hydrogen Water Chemistry Guidelines -- 1987 Revision. It expands on the previous guidelines documents by covering the economic implications of BWR water chemistry control

  1. BWR normal water chemistry guidelines: 1986 revision

    International Nuclear Information System (INIS)

    Boiling water reactors (BWRs) have experienced stress corrosion cracking in the reactor cooling system piping resulting in adverse impacts on plant availability and personnel radiation exposure. The BWR Owners Group and EPRI have sponsored a major research and development program to provide remedies for this stress corrosion cracking problem. This work shows that the likelihood of cracking depends on the plant's water chemistry performance (environment) as well as on material condition and stress level. Plant experience and other research demonstrate that water quality also affects fuel performance and radiation field buildup in BWRs. This report,''BWR Normal Water Chemistry Guidelines: 1986 Revision,'' presents suggested generic water chemistry specifications, justifies the proposed water chemistry limits, suggests responses to out-of-specification water chemistry, discusses available chemical analysis methods as well as data management and surveillance schemes, and details the management philosophy required to successfully implement a water chemistry control program. An appendix contains recommendations for water quality of auxiliary systems. 73 refs., 20 figs., 9 tabs

  2. Optimization of the water chemistry of the primary coolant at nuclear power plants with VVER

    International Nuclear Information System (INIS)

    Results of the use of automatic hydrogen-content meter for controlling the parameter of 'hydrogen' in the primary coolant circuit of the Kola nuclear power plant are presented. It is shown that the correlation between the 'hydrogen' parameter in the coolant and the 'hydrazine' parameter in the makeup water can be used for controlling the water chemistry of the primary coolant system, which should make it possible to optimize the water chemistry at different power levels

  3. Water Treatment Technology - Chemistry/Bacteriology.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chemistry/bacteriology provides instructional materials for twelve competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: waterborne diseases, water sampling…

  4. Water chemistry and materials degradation in LWR'S

    International Nuclear Information System (INIS)

    Water chemistry plays a major role in corrosion, in erosion corrosion and in activity transport in NPPs; it impacts upon the operational safety of LWRs in two main ways: integrity of pressure boundary materials and activity transport and out-of-core radiation fields. A good control of water chemistry can significantly reduce these problems and improve plant safety, but economic pressures are leading to more rigorous operating conditions: fuel burnups are to be increased, higher efficiencies are to be achieved by running at higher temperatures and plant lifetimes are to be extended. Typical water chemistry specifications used in PWR and BWR plants are presented and the chemistry optimization is discussed. The complex interplay of metallurgical, mechanical and environmental factors in environmental sensitive cracking is shown, with details on studies for carbon steels, stainless steels and nickel base alloys. 20 refs., 8 figs., 4 tabs

  5. Primary water chemistry monitoring from the point of view of radiation build-up

    International Nuclear Information System (INIS)

    Basic operational principles of a computer code system calculating the primary circuit corrosion product activities based on actual measured plant chemistry data are presented. The code system consists of two parts: FeSolub.prg: calculates the characteristic iron solubilities based on actual primary water chemistry (H3BO3KOH, ... etc.) and plant load (MW) data. A developed solubility calculation method has been applied fitted to magnetite solubility data of several authors; RADTRAN.exe: calculates primary circuit water and surface corrosion product activities based on results of FeSolub.prg or planned water chemistry data up to the next shutdown. The computer code system is going to be integrated into a general primary water chemistry monitoring and surveillance system. (author). 15 refs, 4 figs, 3 tabs

  6. Modeling the electrochemistry of the primary circuits of light water reactors

    International Nuclear Information System (INIS)

    To model the corrosion behaviors of the heat transport circuits of light water reactors, a mixed potential model (NTM) has been developed and applied to both boiling water reactors (BWRs) and pressurized water reactors (PWRs). Using the data generated by the GE/UKEA-Harwell radiolysis model, electrochemical potentials (ECPs) have been calculated for the heat transport circuits of eight BWRs operating under hydrogen water chemistry (HWC). By modeling the corrosion behaviors of these reactors, the effectiveness of HWC at limiting IGSCC and IASCC can be determined. For simulating PWR primary circuits, a chemical-radiolysis model (developed by the authors) was used to generate input parameters for the MPM. Corrosion potentials of Type 304 and 316 SSs in PWR primary environments were calculated using the NTM and were found to be in good agreement with the corrosion potentials measured in the laboratory for simulated PWR primary environments

  7. 5. International seminar on primary and secondary side water chemistry of nuclear power plants

    International Nuclear Information System (INIS)

    The major subjects of the meetings are: water chemistry of primary and secondary coolant circuits of PWR type reactors (mainly WWER types), corrosion of steam generators, decontamination processes, treatment of radioactive waste waters and related subjects. All the 29 papers were individually indexed and abstracted for the INIS database. (R.P.)

  8. Water chemistry evolution through the critical zone

    OpenAIRE

    Kim, Hyojin

    2014-01-01

    Water as it passes through the critical zone - from top of the trees to the bottom of the groundwater table - plays a critical role in chemical weathering of rocks and in the global carbon cycle. Although the chemistry of surface water (i.e. rivers and lakes) has been intensively monitored at high-frequency (

  9. Single Molecule Junctions: Probing Contact Chemistry and Fundamental Circuit Laws

    Energy Technology Data Exchange (ETDEWEB)

    Hybertsen M. S.

    2013-04-11

    By exploiting selective link chemistry, formation of single molecule junctions with reproducible conductance has become established. Systematic studies reveal the structure-conductance relationships for diverse molecules. I will draw on experiments from my collaborators at Columbia University, atomic-scale calculations and theory to describe progress in two areas. First, I will describe a novel route to form single molecule junctions, based on SnMe3 terminated molecules, in which gold directly bonds to carbon in the molecule backbone resulting in near ideal contact resistance [1]. Second, comparison of the conductance of junctions formed with molecular species containing either one backbone or two backbones in parallel allows demonstration of the role of quantum interference in the conductance superposition law at the molecular scale [2].

  10. Coolant technology of water cooled reactors. V. 1: Chemistry of primary coolant in water cooled reactors

    International Nuclear Information System (INIS)

    This report is a summary of the work performed within the framework of the Coordinated Research Programme on Investigations on Water Chemistry Control and Coolant Interaction with Fuel and Primary Circuit Materials in Water Cooled Power Reactors organized by the IAEA and carried out from 1987 to 1991. It is the continuation of a programme entitled Reactor Water Chemistry Relevant to Coolant-Cladding Interaction (IAEA-TECDOC-429), which ran from 1981 to 1986. Subsequent meetings resulted in the title of the programme being changed to Coolant Technology of Water Cooled Reactors. The results of this Coordinated Research Programme are published in four volumes with an overview in the Technical Reports Series. The titles of the volumes are: Volume 1: Chemistry of Primary Coolant in Water Cooled Reactors; Volume 2: Corrosion in the Primary Coolant Systems of Water Cooled Reactors; Volume 3: Activity Transport Mechanisms in Water Cooled Reactors; Volume 4: Decontamination of Water Cooled Reactors. These publications should be of interest to experts in water chemistry at nuclear power plants, experts in engineering, fuel designers, research and development institutes active in the field and to consultants to these organizations. Refs, figs and tabs

  11. PHYSICAL CHEMISTRY CHARACTERIZATION OF PRINTED CIRCUIT BOARD OF MOBILE PHONES

    Directory of Open Access Journals (Sweden)

    Hellington Bastos da Silva de Sant’ana

    2015-07-01

    Full Text Available Nowadays, electronics industry is the leading sector in developing new technologies. These new technologies lead to cheaper products increasing the consumption. The lifetime of such products is relatively short and soon it becomes waste, known as electronic waste. Cell phone is a common electronic waste. This waste represents an interesting raw material, because it contains large amount of base metals, considerable amount of valuable metals and also those dangerous. In this work, the electronic waste was submitted to mechanical processing: initially the devices were separated into two categories, as year of release (2002 and disassembled manually. The printed circuit boards were milled below 1 mm and then submitted to density and magnetic separation processes. The fractions obtained during the mechanical processing were characterized by chemical analysis. Using mechanical processing it was possible to obtain metal fractions of 80 wt%. A leaching test was carried out to determine if a waste needs to be managed as a hazardous; so that, cell phone waste must be considered in the category of hazardous residue because the lead concentration was above the limit established by Brazilian Standards

  12. Development of electromagnetic filtration in the feed water circuits

    International Nuclear Information System (INIS)

    Electromagnetic filtration in the feed water circuit of the steam generators in nuclear power plants is efficient towards insoluble corrosion products. The principle of electromagnetic filtration is shortly recalled and the results of corresponding development work are summarized. The magnitude of water volumes to be treated on the two priviledged parts of the circuit are estimated. These parts are on the feed water tank level and on the blow-down of the steam generator. The practical applications are discussed

  13. Optimization of operational water chemistry for supercritical-water cooled reactor

    International Nuclear Information System (INIS)

    The paper summaries the experimental results obtained within the project 'PRAMEK'. The project is focused on the study of the compatibility of the construction material of fossil-fueled supercritical water cooled power plants and water chemistry, that is currently used and optimization the dosing of the chemical species to the working circuit. The experience from the project enables to evaluate the water chemistry for Supercritical water cooled reactor (SCWR) and the transfer of the operational experience to the operation of the future nuclear power plant. The used materials are candidate for the SCWR and used in the industrial scale in the Ledvice power plant (fossil fuelled) with the supercritical parameters of the medium. It illustrates the future behaviour in the SCWR plant. The influence of the irradiation will be tested in future within the supercritical water loop in the reactor LVR-15. (author)

  14. Knowledge-based diagnosis of PWR secondary water chemistry

    International Nuclear Information System (INIS)

    A prototype knowledge-based diagnostic system has been developed for more effective processing of the in-line chemistry sensor data from the PWR secondary water-steam circuit with the SUN 3/80 workstation and the Nexpert Object shell program. The system consists of the data interface, the data interpreter, the CHEMISTRY-expert, the ACTION-expert, and the user interface. The knowledge base defines physical and conceptual models of the target domain in a class/object hierarchy, giving rise to a reduced number of rules with pattern matching. The rule base is broken down into separate rule groups for task control, classification, prioritization, and diagnosis to minimize the inference time. The system is scheduled for the Verification and Validation test to collect operational information feedback in one of the Korea nuclear power plants in the near future. (author)

  15. EPRI BWR Water Chemistry Guidelines Revision

    International Nuclear Information System (INIS)

    BWRVIP-190: BWR Water Chemistry Guidelines – 2008 Revision has been revised. The revision committee consisted of U.S. and non-U.S. utilities (members of the BWR Vessel and Internals Protection (BWRVIP) Mitigation Committee), reactor system manufacturers, fuel suppliers, and EPRI and industry experts. The revised document, BWRVIP-190 Revision 1, was completely reformatted into two volumes, with a simplified presentation of water chemistry control, diagnostic and good practice parameters in Volume 1 and the technical bases in Volume 2, to facilitate use. The revision was developed in parallel and in coordination with preparation of the Fuel Reliability Guidelines Revision 1: BWR Fuel Cladding Crud and Corrosion. Guidance is included for plants operating under normal water chemistry (NWC), moderate hydrogen water chemistry (HWC-M), and noble metal application (GE-Hitachi NobleChem™) plus hydrogen injection. Volume 1 includes significant changes to BWR feedwater and reactor water chemistry control parameters to provide increased assurance of intergranular stress corrosion cracking (IGSCC) mitigation of reactor materials and fuel reliability during all plant conditions, including cold shutdown (≤200°F (93°C)), startup/hot standby (>200°F (93°C) and ≤ 10%) and power operation (>10% power). Action Level values for chloride and sulfate have been tightened to minimize environmentally assisted cracking (EAC) of all wetted surfaces, including those not protected by hydrogen injection, with or without noble metals. Chemistry control guidance has been enhanced to minimize shutdown radiation fields by clarifying targets for depleted zinc oxide (DZO) injection while meeting requirements for fuel reliability. Improved tabular presentations of parameter values explicitly indicate levels at which actions are to be taken and required sampling frequencies. Volume 2 provides the technical bases for BWR water chemistry control for control of EAC, flow accelerated corrosion

  16. On 2D water chemistry

    International Nuclear Information System (INIS)

    The micro-structural behaviour of density fluctuations in liquid water shows that the hydrogen-bonds lifetime is 1-20 ps whereas the broken-bonds lifetime is about 0.1 ps. Therefore spontaneously broken bonds will probably reform to give the original hydrogen bond configuration, but their coherent breakage in molecular cluster will lead to rotation of water molecules around the remaining hydrogen bonds. Our model for topological structure of dense part of liquid water in its density fluctuations as helical tetrahedral clusters is useful for explanation of liquid-water structural anomalies including the high quantity of hydrogen bonds with tetrahedral orientation in non-ordered liquid matrix. The topology of such the clusters is essentially differed from topology of crystalline ice. From this and only this point of view, water can be considered as a two-structural liquid because the formation and decay of such the clusters has dynamic character and is natural consequence of condensed-matter density fluctuations. At a hydrogen-steam (or oxygen-steam) mixture is injected in aqueous solution, it is possible to obtain the stable gaseous nano-bubbles. Such the nano-fluid can convert the liquid water in the non-stoichiometric state, H2O1±z, and (without impurity addition) change its Reduction-Oxidation (Redox) potential. In this connection, we offer to use Fermi level of electron energy in the aqueous solution for correct expressing Redox potential of non-stoichiometric water. If Fermi level will be about in the middle of the band gap, the average number of electrons per quantum state of a reducing agent will be zero and the same factor for the oxidizing one will be unity that is the chemical activity of these agents will be zero. At the same time, the liquid-water non-stoichiometric composition, H2O1±z, is varied in the very narrow range of z ≤ 10-6. Therefore it is important monitoring the Redox potential (Fermi level) online by precise sensor having the exact

  17. Reactor water chemistry relevant to coolant-cladding interaction

    International Nuclear Information System (INIS)

    The report is a summary of the work performed in a frame of a Coordinated Research Program organized by the IAEA and carried out from 1981 till 1986. It consists of a survey on our knowledge on coolant-cladding interaction: the basic phenomena, the relevant parameters, their control and the modelling techniques implemented for their assessment. Based upon the results of this Coordinated Research Program, the following topics are reviewed on the report: role of water chemistry in reliable operation of nuclear power plants; water chemistry specifications and their control; behaviour of fuel cladding materials; corrosion product behaviour and crud build-up in reactor circuits; modelling of corrosion product behaviour. This report should be of interest to water chemistry supervisors at the power plants, to experts in utility engineering departments, to fuel designers, to R and D institutes active in the field and to the consultants of these organizations. A separate abstract was prepared for each of the 3 papers included in the Annex of this document. Refs, figs, tabs

  18. Chemistry management of generator stator water system

    International Nuclear Information System (INIS)

    Chemistry management of water cooled turbine generators with hollow copper conductors is very essential to avoid possible re-deposition of released copper oxides on stator windings, which otherwise may cause flow restrictions by partial plugging of copper hollow conductors and impair cooling. The phenomenon which is of more concern is not strictly of corrosion failure, but the consequences caused by the re-deposition of copper oxides that were formed by reaction of copper with oxygen. There were also some Operating experiences (OE) related to Copper oxide fouling in the system resulting shut down/off-line of plants. In Madras Atomic Power Station (MAPS), the turbine generator stator windings are of Copper material and cooled by demineralized water passing through the hollow conductors. The heated water from the stator is cooled by process water. A part of the stator water is continuously passed through a mixed bed polisher to remove any soluble ionic contaminants to maintain the purity of system water and also maintain copper content as low as possible to avoid possible re-deposition of released copper oxides on stator windings. The chemistry regime employed is neutral water with dissolved oxygen content between 1000-2000 ppb. Chemistry management of Stator water system was reviewed to know its effectiveness. Detailed chemical analyses of the spent resins from the polishing unit were carried out in various campaigns which indicated only part exhaustion of the polishing unit resins and reasonably low levels of copper entrapment in the resins, thus highlighting the effectiveness of the in-practice chemistry regime. (author)

  19. Geometric structure of chemistry-relevant graphs zigzags and central circuits

    CERN Document Server

    Deza, Michel-Marie; Shtogrin, Mikhail Ivanovitch

    2015-01-01

    The central theme of the present book is zigzags and central-circuits of three- or four-regular plane graphs, which allow a double covering or covering of the edgeset to be obtained. The book presents zigzag and central circuit structures of geometric fullerenes and several other classes of graph of interest in the fields of chemistry and mathematics. It also discusses the symmetries, parameterization and the Goldberg–Coxeter construction for those graphs. It is the first book on this subject, presenting full structure theory of such graphs. While many previous publications only addressed particular questions about selected graphs, this book is based on numerous computations and presents extensive data (tables and figures), as well as algorithmic and computational information. It will be of interest to researchers and students of discrete geometry, mathematical chemistry and combinatorics, as well as to lay mathematicians.

  20. Predicted impact of power coastdown operations on the water chemistry for two domestic boiling water reactors

    International Nuclear Information System (INIS)

    A theoretical model was adapted to evaluate the impact of power coastdown on the water chemistry of two commercial boiling water reactors (BWRs) in this work. In principle, the power density of a nuclear reactor upon a power level decrease would immediately be lowered, followed by water chemistry variations due to reduced radiolysis of water and extended coolant residence times in the core and near-core regions. It is currently a common practice for commercial BWRs to adopt hydrogen water chemistry (HWC) for corrosion mitigation. The optimal feedwater hydrogen concentration may be different after a power coastdown is implemented in a BWR. A computer code DEMACE was used in the current study to investigate the impact of various power coastdown levels on major radiolytic species concentrations and electrochemical corrosion potential (ECP) behavior of components in the primary coolant circuit of two domestic reactors operating under either normal water chemistry or HWC. Our analyses indicated that under a rated core flow rate the oxidizing species concentrations and the ECP did not vary monotonously with decreases in reactor power level at a fixed feedwater hydrogen concentration. In particular, ECP variations basically followed the patterns of hydrogen peroxide in the select regions and exhibited high values at power levels of 95% and 90% for Chinshan-1 and Kuosheng-1, respectively. (author)

  1. Water chemistry features of advanced heavy water reactor

    International Nuclear Information System (INIS)

    Advanced Heavy Water Reactor (AHWR) being designed in India proposes to use Plutonium and Thorium as fuel. The objective is to extract energy from the uranium-233 formed from Thorium. It is a heavy water moderated and light water cooled tube type boiling water reactor. It is a heavy water moderated and light water cooled tube type boiling water reactor. It is a natural circulation reactor. Thus, it has got several advanced passive safety features built into the system. The various water coolant systems are listed below. i) Main Heat transport System ii) Feed water system iii) Condenser cooling system iv) Process water system and safety systems. As it is a tube type reactor, the radiolysis control differs from the normal boiling water reactor. The coolant enters the bottom of the coolant channel, boiling takes place and then the entire steam water mixture exits the core through the long tail pipes and reaches the moisture separator. Thus, there is a need to devise methods to protect the tail pipes from oxidizing water chemistry condition. Similarly, the moderator heavy water coolant chemistry differs from that of moderator system chemistry of PHWR. The reactivity worth per ppm of gadolinium and boron are low in comparison to PHWR. As a result, much higher concentration of neutron poison has to be added for planned shutdown, start up and for actuating SDS-2. The addition of higher concentration of neutron poison result in higher radiolytic production of deuterium and oxygen. Their recombination back to heavy water has to take into account the higher production of these gases. This paper also discusses the chemistry features of safety systems of AHWR. In addition, the presentation will cover the chemistry monitoring methodology to be implemented in AHWR. (author)

  2. Water chemistry: industrial and power station water treatment

    International Nuclear Information System (INIS)

    This book is a blend of basic information on water chemistry at both ambient and high temperature, as well as the problems encountered during wide spread use of water as the fluid for heat transfer in industry. Emphasis is also on steam generating systems and steam quality requirements for high pressure turbines. Special problems of water chemistry and material compatibility in nuclear power stations are also given. A few aspects of both natural waters and effluent treatment systems have also been touched upon briefly

  3. Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC)

    International Nuclear Information System (INIS)

    This report presents the results of the Coordinated Research Project (CRP) on Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plants (FUWAC, 2006-2009). It provides an overview of the results of the investigations into the current state of water chemistry practice and concerns in the primary circuit of water cooled power reactors including: corrosion of primary circuit materials; deposit composition and thickness on the fuel; crud induced power shift; fuel oxide growth and thickness; radioactivity buildup in the reactor coolant system (RCS). The FUWAC CRP is a follow-up to the DAWAC CRP (Data Processing Technologies and Diagnostics for Water Chemistry and Corrosion Control in Nuclear Power Plants 2001-2005). The DAWAC project improved the data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (NPPs). With the improved methods for controlling and monitoring water chemistry now available, it was felt that a review of the principles of water chemistry management should be undertaken in the light of new materials, more onerous operating conditions, emergent issues such as CIPS, also known as axial offset anomaly (AOA) and the ageing of operating power plant. In the framework of this CRP, water chemistry specialists from 16 nuclear utilities and research organizations, representing 15 countries, exchanged experimental and operational data, models and insights into water chemistry management. The CD-ROM attached to this IAEA-TECDOC includes the report itself, detailed progress reports of three Research Coordination Meetings (RCMs) (Annexes I-III) and the reports and presentations made during the project by the participants.

  4. Real time water chemistry monitoring and diagnostics

    International Nuclear Information System (INIS)

    EPRI has produced a real time water chemistry monitoring and diagnostic system. This system is called SMART ChemWorks and is based on the EPRI ChemWorks codes. System models, chemistry parameter relationships and diagnostic approaches from these codes are integrated with real time data collection, an intelligence engine and Internet technologies to allow for automated analysis of system chemistry. Significant data management capabilities are also included which allow the user to evaluate data and create automated reporting. Additional features have been added to the system in recent years including tracking and evaluation of primary chemistry as well as the calculation and tracking of primary to secondary leakage in PWRs. This system performs virtual sensing, identifies normal and upset conditions, and evaluates the consistency of on-line monitor and grab sample readings. The system also makes use of virtual fingerprinting to identify the cause of any chemistry upsets. This technology employs plant-specific data and models to determine the chemical state of the steam cycle. (authors)

  5. Setting up the water chemistry for thermal water treatment

    Science.gov (United States)

    Boglovskii, A. V.; Chernozubov, V. B.; Chernykh, N. E.; Gorbunov, A. V.; Birdin, R. Kh.

    2007-07-01

    Results are presented from the development and setting up of water-chemistry conditions for a thermal water treatment process that allows saline effluents from a boiler house to be eliminated. Peculiarities of reducing scale formation in the evaporator through the use of chalk primer and type PAF-13A antiscale agent are discussed. The results of industrial tests of a thermal water treatment plant are presented that confirm the possibility of producing makeup water for heating networks and steam boilers.

  6. Water chemistry of the secondary loop of pressurized water reactors

    International Nuclear Information System (INIS)

    The problems of water chemistry in the steam-water-cycle of a PWR are reviewed. The hydrolysis of salts in the secondary loop was investigated theoretically. The control of the whole system, the operating of single systems and the concentration of contaminants are treated specially. A program has been developed for the operation under optimal conditions. (orig.)

  7. Uncommon water chemistry observations in modern day boiling water reactors

    International Nuclear Information System (INIS)

    Numerous technologies have been developed to mitigate intergranular stress corrosion cracking (IGSCC) of boiling water reactor (BWR) materials that include hydrogen water chemistry (HWC), noble metal chemical application (NMCA) and on-line NMCA (OLNC). These are matured technologies with extensive plant operating experiences, HWC – 32 years, NMCA – 18 years and OLNC – 9 years. Over the past three decades, numerous water chemistry data, dose rate data and IGSCC mitigation data relating to these technologies have been published and presented at many international conferences. However, there are many valuable and critical water chemistry and dose rate data that have gone unnoticed and unreported. The purpose of this paper is to highlight some of the uncommon water chemistry and dose rate experiences that reveal valuable information on the performance and durability of NMCA and OLNC technologies. Data will be presented, that have hitherto been unseen in public domain, from the lead OLNC plant in Switzerland giving reasons for some of the uncommon or overlooked water chemistry observations. They include, decreasing reactor water platinum concentration with each successive OLNC application, lack of increase in reactor water activation products in later applications, gradual disappearance of main steam line radiation (MSLR) monitor response decrease, Curium and Au-199 release during OLNC applications, rapid increase in reactor water clean-up conductivity, and Iodine, Mo-99 and Tc-99m spiking when hydrogen is interrupted and brought back to service, and main steam and reactor water conductivity spiking when clean-up beds or condensate demineralizers are changed. All these observations give valuable information on the success of OLNC applications and also signal the presence of sufficient noble metal on in-reactor surfaces from the long term durability and effectiveness stand point. Some of these observations can be used as secondary parameters, if and when a primary

  8. Water chemistry of breeder reactor steam generators

    International Nuclear Information System (INIS)

    The water quality requirements will be described for breeder reactor steam generators, as well as specifications for balance of plant protection. Water chemistry details will be discussed for the following power plant conditions: feedwater and recirculation water at above and below 5% plant power, refueling or standby, makeup water, and wet layup. Experimental data will be presented from tests which included a departure from nucleate boiling experiment, the Few Tube Test, with a seven tube evaporator and three tube superheater, and a verification of control and on-line measurement of sodium ion in the ppB range. Sampling and instrumentation requirements to insure adherence to the specified water quality will be described. Evaporator cleaning criteria and data from laboratory testing of chemical cleaning solutions with emphasis on flow, chemical composition, and temperature will be discussed

  9. IAEA programme on water chemistry in nuclear power plants

    International Nuclear Information System (INIS)

    The paper reviews the past future efforts of the IAEA, directed to ensure optimal water chemistry regimes in nuclear power plants. Corrosion of structural materials resulting from the interaction of the coolant with the internal surfaces comprising the primary heat transfer and auxiliary circuits of water reactors, creates two main problems. The first is an operational problem resulting in an increase in the core pressure drop or overheating of the fuel elements induced by crud buildup on the fuel cladding. The second problem is related to occupational radiation exposures arising from contamination of out-of-flux surfaces by corrosion products activated in the reactor core. These are the problems of reliability and safety which together with economics could be considered as the 'three whales' of nuclear power. The main goals of international cooperation in reactor water chemistry are: (1) to create a balanced and well-grounded methodological basis for corresponding regulatory and engineering solutions on a national level and (2) to improve 'the models and predictive capability of specialists for conditions that are different from or perhaps just beyond the realm of experience'. Continuing efforts are required to guarantee the highest reliability and safety standards under favorable economic indices of nuclear power plants, and to obtain understanding of such significant potential for solving the remaining problems. (Nogami, K.)

  10. Pore water chemistry of the febex bentonite

    International Nuclear Information System (INIS)

    The knowledge of pore water chemistry in the clay barrier is essential for performance assessment purposes in a nuclear waste repository, since the pore water composition controls the processes involved in the release and transport of the radionuclides. The methodology followed to define the representative composition of the FEBEX bentonite pore water is presented in this paper. A series of bentonite-water interaction tests have been performed with the aim of providing a database on the main chemical parameters of the bentonite. These tests were carried out both with high solid to liquid (s:l) ratios (squeezing tests) and low s:l ratios (aqueous extracts tests). The exchangeable cations have also been analyzed to determine the selectivity coefficient of the exchange reactions. To complete the data set, a physical and mineralogical characterization of the bentonite was made. The most significant bentonite-water interaction processes controlling the chemistry of the system was identified. The ion concentrations basically depend on the s:l ratio of the system, and the pore water composition is controlled by the dissolution of chlorides, dissolution/precipitation of carbonates and sulphates and the cation exchange reactions in the smectite. The bentonite/water system was modelled with the PHREEQC2 program to obtain the best possible estimation of the pore water composition for initial conditions of water content (=14%), after checking the conceptual model with the experimental results. The model predictions fitted satisfactorily with the experimental data at low s:l ratios. At high s:l ratios, the modelled results agree adequately, except for the sulphate content, which could be affected by the effective porosity, anion exclusion or stagnant zones not taken into account in the model. According to the model, the FEBEX bentonite pore water at 14% moisture is a sodium-chloride type, with an ionic strength of 0.25 M and pH of 7.78. Copyright (2001) Material Research

  11. Design Features of the SMART Water Chemistry

    International Nuclear Information System (INIS)

    The design features for the primary water chemistry for the SMART are introduced from the viewpoint of the system characteristics and the chemical design concept. The most essential differences in water chemistry between the commercially operating PWRs and SMART are characterized by the presence of boron in the water and the operating mode of the purification system. SMART is a soluble boron free reactor, and the ammonia is used as a pH reagent. The material for SMART steam generator is also different from the standard material of the commercially operating PWRs: titanium alloy for the steam generator tubes. In SMART hydrogen gas which suppresses a generation of oxidizing species by the radiolysis processes in the reactors is not added to the primary coolant, but is normally generated from the radiolysis of the ammonia as the coolant passes through the core. Ammonia is added once per shift because SMART reactor has no letdown and charging system during power operation. Because of these competing processes, the concentrations of hydrogen, nitrogen and ammonia in the primary coolant are in equilibrium, which depend on the decomposition and/or combination rate of the ammonia. The level of permissible oxygen concentration in the primary coolant can be ensured by both suppression of the water radiolysis through maintaining a high enough hydrogen concentration in the primary coolant and by a restriction of the oxygen ingress into the primary coolant with the makeup water. The ammonia chemistry in SMART reactor eliminates the need for hydrogen injection for the control of the dissolved oxygen in the primary coolant because of spontaneous generation of hydrogen and nitrogen produced by the reaction of the ammonia decomposition. (authors)

  12. Water chemistry in operating nuclear power plants

    International Nuclear Information System (INIS)

    The R and D investigations in chemistry and biology in coolant waters have to be performed more in the 'field' than in the laboratory. There are three main reasons for it. Essentially the power plant utility is the user of the R and D results and hence the results have to be applicable immediately in the plant, yield desirable results and must be reproducible and should not lead to any regulatory or safety problem for the plant. Several utilities in the country and abroad encounter types of operational constraints which may not have identical solutions even though the system and chemistry domain are identical by design and concept. Hence the R and D solutions are to be improvised periodically for the same system. The physical conditions, materials and metallurgy of engineering systems get revised periodically to enhance power production at cheaper rates. This is another driving force for R and D in water chemistry. Environmental compliance for any discharge from power plant is taken very seriously because of the potential danger not only to the human population around but also to the different forms of biota

  13. Performance Analysis of Various Readout Circuits for Monitoring Quality of Water Using Analog Integrated Circuits

    Directory of Open Access Journals (Sweden)

    Pawan Whig

    2012-10-01

    Full Text Available This paper presents a comparative performance study of various analog integrated circuits (namely CC-II, DVCC, CDBA and CDTA used with ISFET for monitoring the quality of water. The use of these active components makes the implementation simple and attractive. The functionality of the circuits are tested using Tanner simulator version 15 for a 70nm CMOS process model also the transfer functions realization for each is done on MATLAB R2011a version, the Very high speed integrated circuit Hardware description language(VHDL code for all scheme is simulated on Xilinx ISE 10.1 and various simulation results are obtained and its is found that DVCC is most stable and consume maximum power whereas CC-II is the least stable and consumes minimum power amongst all the four deployed analog IC’s. Detailed simulation results are included in the paper to give insight into the research work carried out.

  14. Water chemistry management of nuclear power plant. Water chemistry management of BWR plant

    International Nuclear Information System (INIS)

    There are two kinds of nuclear power plants such as Boiling Water Reactor (BWR) and Pressurized Water Reactor (PWR) in Japan. In this paper, a water chemistry management of BWR plant is explained. BWR plant makes steam produced in the reactor send to the turbine and produce power, then condensate in the main condenser and use again as feed water. The objects of water chemistry management of BWR are security of good conditions of fuel and structure materials and reduction of the dose equivalent and the radioactive waste. The volume of coolant depends on the temperature change, the concentration of boric acid for neutron absorber, lithium hydroxide for pH control and hydrogen gas for corrosion are controlled. Impurity metals in water of reactor are removed by the condensate demineralizer. The concentration of boron and lithium is controlled from 0 to 4000 ppm and from 0.2 to 2.2 ppm, respectively. On water chemistry technologies for dose reduction, oxygen injection into feed water and control operation of rate of Ni/Fe are explained. On the technologies for preventive maintenance, degassing operation of reactor and hydrogen injection into feed water are described. (S.Y.)

  15. Corrosion and water chemistry studies at Halden

    International Nuclear Information System (INIS)

    A PWR facility installed in the Halden reactor is being used to determine the effects of high lithium concentration (high pH) on the corrosion behaviour of high burn-up Zircaloy-4 fuel rods subjected either to nucleate boiling or to one-phase cooling conditions. Pre-test as well as interim oxide layer thickness measurements have been performed on the test segments, and comparisons made with predicted values based on model calculations. The oxide thicknesses measured at an average burn-up above 40 MWd/kgUO2 are consistent with literature data and show no evidence of corrosion enhancement due to the high lithium content. Presence of crud deposits was noted at the cooler end of the rods exposed to one phase cooling conditions. The experiment will continue until October 1991, when anticipated maximum oxide thicknesses will be in the range 80-100 μm. A BWR facility, dedicated to exploring the effects of environmental variables on the irradiation assisted stress corrosion cracking (IASCC) behaviour of in-core structural component materials is described. The main objectives of the study, which are to evaluate the effects of water chemistry, fluence, stress level and alloy composition on cracking propensity, are discussed. The water chemistry monitoring facilities at Halden are mentioned

  16. Experience with the secondary water chemistry in the pressurized water reactor nuclear power stations of Electricite de France (EdF)

    International Nuclear Information System (INIS)

    Good water chemistry is essential for avoiding corrosion problems on components in the secondary circuit of PWR plants. EdF's central laboratory specifies the water quality for the different circuits. All specified chemical data are analysed, fed into the central computer and can be compared on each occasion with previous data or with similar data from other plants. The corrosion behaviour of individual components in the secondary circuit is described. Corrosion has not been observed in the steam generators on the secondary side of any plant. The main corrosion problem has been erosion-corrosion of carbon steels in systems in contact with water or steam in ancillary plants. (orig.)

  17. The chemistry of the PSGHWR heavy water moderator system

    International Nuclear Information System (INIS)

    The PSGHWR heavy water moderator and helium overblanket circuits, and the heavy water purification plant are described. Details of the deuterisation and dedeuterisation of ion exchange resin charges for the purification plant are given, and a pattern of consistency over seventeen deuterisations of anion and cation beds is shown. The chemistry specification for the moderator system is given, and the changing philosophy of ion exchange plant operation to maintain this specification, from early operation with continuous flow through cation and anion clean up columns, to the current mode of minimum intermittent flow, is explained. Anionic and cationic impurities and radio nuclides found in the moderator are listed, and their sources examined. The inter-relation between the ion exchange plant as a source as well as a remover of impurities and the part played by peroxide is examined. Radiolysis data is presented and an attempt is made to explain the correlation between radiolysis rate and impurity concentrations, ion exchange column operation and other plant parameters. A soluble poison, enriched 10boron, is used for balancing excess fuel reactivity. The boron cycle and method of control of boron concentration are explained, and experience of anion exchange resin capacity for boron at different input concentrations is given. Experience covering 26 regenerations of the anion beds, mostly using deutero chemicals, and details of the method of recovery of deuteroboric acid and potassium deuteroxide by electrodialysis are given. Finally, heavy water losses and isotopic degradation of D2O during 8 years of operation are examined. (author)

  18. Survey of Water Chemistry and Corrosion of NPP

    International Nuclear Information System (INIS)

    Status of water chemistry of nuclear power plant and materials corrosion has been surveyed. For PWR, system chemistry of primary coolant and secondary coolant as well as the related corrosion of materials was surveyed. For BWR, system chemistry as whole has been surveyed with its accompanying corrosion problems. Radiolysis of coolant water and activation of corrosion products also was surveyed. Future NPP such as supercritical water cooled reactor and fusion reactor has also been surveyed for their water chemistry and corrosion problems. As a result, proposal for some research items has been suggested. Some related corrosion research techniques and electrochemical fundamentals are also presented

  19. Survey of Water Chemistry and Corrosion of NPP

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Sok; Hong, Bong Geon

    2008-06-15

    Status of water chemistry of nuclear power plant and materials corrosion has been surveyed. For PWR, system chemistry of primary coolant and secondary coolant as well as the related corrosion of materials was surveyed. For BWR, system chemistry as whole has been surveyed with its accompanying corrosion problems. Radiolysis of coolant water and activation of corrosion products also was surveyed. Future NPP such as supercritical water cooled reactor and fusion reactor has also been surveyed for their water chemistry and corrosion problems. As a result, proposal for some research items has been suggested. Some related corrosion research techniques and electrochemical fundamentals are also presented.

  20. Water chemistry and behavior of materials in PWRs and BWRs

    International Nuclear Information System (INIS)

    Water chemistry plays a major role in corrosion and in activity transport in NPP's. Although a full understanding of all mechanisms involved in corrosion does not exist, controlling of the water chemistry has achieved good results in recent years. Water chemistry impacts upon the operational safety of LWR's in two main ways: integrity of pressure boundary materials and, activity transport and out-of-core radiation fields. This paper will describe application of water chemistry control in operating reactors to prevent corrosion. Some problems experienced in LWR's will be reviewed for the design of the nuclear heating reactors (NHR). (author). 18 refs, 10 figs, 5 tabs

  1. Data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (DAWAC). Report of a coordinated research project 2001-2005

    International Nuclear Information System (INIS)

    This publication provides information on the current status and development trends in monitoring, diagnostics and control of water chemistry and corrosion of core and primary circuit materials in water cooled power reactors. It summarizes the results of an IAEA Coordinated Research Project and focuses on the methods for development, qualification and implementation of water chemistry expert systems at nuclear power plants. These systems are needed to have full benefit from using on-line sensors in real time mode when sensor signals, and other chemistry and operational data, are collected and continuously analysed with data acquisition and evaluation software. Technical knowledge was acquired in water chemistry control techniques (grab sampling, on-line monitoring, data collecting and processing, etc), plant chemistry and corrosion diagnostics, plant monitoring (corrosion, chemistry, activity) and plant chemistry improvement (analytical models and practices). This publication covers contributions from leading experts in water chemistry/corrosion, representing organizations from 16 countries with the largest nuclear capacities

  2. Light water reactor materials and water chemistry studies at Halden

    International Nuclear Information System (INIS)

    The OECD Halden Reactor Project is undertaking several studies aimed at evaluating the effects of coolant chemistry on LWR materials corrosion performance by means of in-pile tests performed in facilities simulating both PWR and BWR environments. A PWR facility has been used to determine the effects of high pH (4-4.5ppm Li) on the corrosion behaviour of Zircaloy-4 cladding material and the results of this investigation are presented. A BWR test facility, dedicated to exploring the effects of environmental variables on the Irradiation Assisted Stress Corrosion Cracking behaviour of stainless steels and nickel-based alloys commonly found in BWRs, is described. The water chemistry monitoring capabilities at Halden are addressed and plans for future studies are discussed. (author)

  3. Water Chemistry Division Progress Report (April 1983 - April 1985)

    International Nuclear Information System (INIS)

    The research and development work of the Water Chemistry Division during the period from April 1983 to April 1985 is reported in the form of individual summaries. The activities of the Division cover the following fields: water and steam chemistry, high temperature studies, single crystal structure by x-ray diffraction, vriable temperature, x-ray powder studies, thermal analysis and thermophysical properties of rare earth compounds and uranium chemistry. (author)

  4. Development of Database and Lecture Book for Nuclear Water Chemistry

    International Nuclear Information System (INIS)

    In order to establish a systematic and synthetic knowledge system of nuclear water chemistry, we held nuclear water chemistry experts group meetings. We discussed the way of buildup and propagation of nuclear water chemistry knowledge with domestic experts. We obtained a lot of various opinions that made the good use of this research project. The results will be applied to continuous buildup of domestic nuclear water chemistry knowledge database. Lessons in water chemistry of nuclear power plants (NPPs) have been opened in Nuclear Training and education Center, KAERI to educate the new generation who are working and will be working at the department of water chemistry of NPPs. The lessons were 17 and lesson period was from 12th May through 5th November. In order to progress the programs, many water chemistry experts were invited. They gave lectures to the younger generation once a week for 2 h about their experiences obtained during working on water chemistry of NPPs. The number of attendance was 290. The lessons were very effective and the lesson data will be used to make database for continuous use

  5. New design architecture decisions on water chemistry support systems at new VVER plants

    Energy Technology Data Exchange (ETDEWEB)

    Kumanina, V.E.; Yurmanova, A.V. [Joint Stock Company Atomenergoproekt, Moscow (Russian Federation)

    2010-07-01

    Major goals of nuclear power plant design upgrading are reduction of cost and construction time with unconditional safety assurance. Main ways of further improvement of nuclear power plant design are as follows: review of the results of research engineering and development and of new technologies; harmonization with international codes and standards; justified liberalization of conservatism based on operating experience and use of improved design codes. Operational experience of Russian and foreign NPPs has shown that the designs of new NPPs could be improved by upgrading water chemistry support systems. Some new design solutions for water chemistry support systems are currently implemented at new WWER plants such as Bushehr, Kudankulam, Belene, Balakovo Units 5 and 6, AES-2006 project. The paper highlights the improvements of the following systems and processes: low temperature high pressure primary coolant clean-up system; primary system surface preconditioning during pre-start hot functional testing; steam generator blowdown cleanup system; secondary water chemistry; phosphate water chemistry in intermediate cooling circuits and other auxiliary systems; alternator cooling system water chemistry; steam generator cleanup and decontamination systems. (author)

  6. New design architecture decisions on water chemistry support systems at new VVER plants

    International Nuclear Information System (INIS)

    Major goals of nuclear power plant design upgrading are reduction of cost and construction time with unconditional safety assurance. Main ways of further improvement of nuclear power plant design are as follows: review of the results of research engineering and development and of new technologies; harmonization with international codes and standards; justified liberalization of conservatism based on operating experience and use of improved design codes. Operational experience of Russian and foreign NPPs has shown that the designs of new NPPs could be improved by upgrading water chemistry support systems. Some new design solutions for water chemistry support systems are currently implemented at new WWER plants such as Bushehr, Kudankulam, Belene, Balakovo Units 5 and 6, AES-2006 project. The paper highlights the improvements of the following systems and processes: low temperature high pressure primary coolant clean-up system; primary system surface preconditioning during pre-start hot functional testing; steam generator blowdown cleanup system; secondary water chemistry; phosphate water chemistry in intermediate cooling circuits and other auxiliary systems; alternator cooling system water chemistry; steam generator cleanup and decontamination systems. (author)

  7. Introduction of water chemistry regimes with ethanolamine metering at nuclear power plants equipped with VVER-type reactors

    Science.gov (United States)

    Shutikov, A. V.; Ivanov, V. N.; Tyapkov, V. F.; Yerpylyova, S. F.; Bykova, V. V.

    2008-05-01

    The results of introduction of water chemistry with ethanolamine metering in the feedwater at unit No. 2 of the Balakovo NPP are presented. Along with the data obtained in the course of operational monitoring of the working medium of the secondary coolant circuit, the results of studying of contamination of the tube system of steam generators are presented and analyzed.

  8. The research of materials and water chemistry for supercritical water-cooled reactors in Research Centre Rez

    International Nuclear Information System (INIS)

    Research Centre Rez (CVR) is R and D company based in the Czech Republic. It was established as the subsidiary of the Nuclear Research Institute Rez plc. One of the main activities of CVR is the research of materials and chemistry for the generation IV reactor systems - especially the supercritical water-cooled one. For these experiments is CVR equipped by a supercritical water loop (SCWL) and a supercritical water autoclave (SCWA) serving for research of material and Supercritical Water-cooled Reactor (SCWR) environment compatibility experiments. SCWL is a research facility designed to material, water chemistry, radiolysis and other testing in SCWR environment, SCWA serves for complementary and supporting experiments. SCWL consists of auxiliary circuits (ensuring the required parameters as temperature, pressure and chemical conditions in the irradiation channel, purification and measurements) and irradiation channel (where specimens are exposed to the SCWR environment). The design of the loop is based on many years of experience with loop design for various types of corrosion/water chemistry experiments. Designed conditions in the test area of SCWL are 600 deg. C and 25 MPa. SCWL was designed in 2008 within the High Performance Light Water Reactor Phase 2 project and built during 2008 and 2009. The trial operations were performed in 2010 and 2011 and were divided into three phases - the first phase to verify the functionality of auxiliary circuits of the loop, the second phase to verify the complete facility (auxiliary circuits and functional irradiation channel internals) and the third phase to verify the feasibility of corrosion tests with the complete equipment and specimens. All three trial operations were very successful - designed conditions and parameters were reached. (authors)

  9. Ground water chemistry and water-rock interaction at Olkiluoto

    International Nuclear Information System (INIS)

    Bedrock investigations for the final repository for low- and intermediate level wastes (VLJ repository) generated at the Olkiluoto (TVO-I and TVO-II) nuclear power plant, stareted in 1980. Since 1988 the area has been investigated for the final disposal of spent nuclear fuel. In the report the geochemistry at the nuclear waste investigation site, Olkiluoto, is evaluated. The hydrogeological data are collected from boreholes drilled down to 1000-m depth into Proterozoic crystalline bedrock. The interpretation is based on groundwater chemistry and isotope data, mineralogical data, and the structure and hydrology of the bedrock, using correlation diagrams and thermodynamic calculations (PHREEQE). The hydrogeochemistry and major processes controlling the groundwater chemistry are discussed. The groundwater types are characterized by water-rock interaction but they also show features of other origins. The fresh and brackish waters are contaminated by varying amounts of young meteoric water and brackish seawater. The saline water contains residues of possibly ancient hydrothermal waters, imprints of which are occasionally seen in the rock itself. Different mixing phenomenas are indicated by the isotope contents (O-l8/H-2, H-3) and the Ca/Cl, Na/Cl, HCO3/Cl, SO4/Cl, Br/Cl, SI(calcite)/SI(dolomite) ratios. The interaction between bedrock and groundwater is reflected by the behaviour of pH, Eh, Ca, Mg, Na, K, Fe, HCO3 and S04. Dissolution and precipitation of calcite and pyrite, and aluminosilicate hydrolysis play the major role in defining the groundwater composition of the above components

  10. Relation between water chemistry and operational safety

    International Nuclear Information System (INIS)

    This report describes the relation between chemistry/radiochemistry and operational safety, the technics bases for chemical and radiochemical parameters and an analysis of the Annual Report of Angra I Operation and OSRAT Mission report to 1989 in this area too. Furthermore it contains the transcription of the technical Specifications related to the chemistry and radiochemistry for Angra I. (author)

  11. The effectiveness of early hydrogen water chemistry on corrosion mitigation for boiling water reactors

    International Nuclear Information System (INIS)

    For mitigating intergranular stress corrosion cracking (IGSCC) in an operating boiling water reactor (BWR), the technology of hydrogen water chemistry (HWC) aiming at coolant chemistry improvement has been adopted worldwide. However, the hydrogen injection system is usually in an idle and standby mode during a startup operation. The coolant in a BWR during a cold shutdown normally contains a relatively high level of dissolved oxygen from intrusion of atmospheric air. Accordingly, the structural materials in the primary coolant circuit (PCC) of a BWR could be exposed to a strongly oxidizing environment for a short period of time during a subsequent startup operation. At some plants, the feasibility of hydrogen water chemistry during startup operations has been studied. It is technically difficult to directly procure water chemistry data at various locations of an operating reactor. Accordingly, the impact of startup operation on water chemistry in the PCC of a BWR operating under HWC can only be theoretically evaluated through computer modelling. In this study, a well-developed computer code DEMACE was used to investigate the variations in redox species concentration and in electrochemical corrosion potential (ECP) of components in the PCC of a domestic BWR during startup operations in the presence of HWC. Simulations were carried out for [H2]FWs ranging from 0.0 to 2.0 parts per million (ppm) and for power levels ranging from 3.8% to 11.3% during startup operations. Our analyses indicated that for power levels with steam generation in the core, a higher power level would tend to promote a more oxidizing coolant environment for the structural components and therefore lead to less HWC effectiveness on ECP reduction and corrosion mitigation. At comparatively lower power levels in the absence of steam, the effectiveness of HWC on ECP reduction was much better. The effectiveness of HWC in the PCC of a BWR during startup operations is expected to vary from location to

  12. Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC). Additional Information

    International Nuclear Information System (INIS)

    This report presents the results of the Coordinated Research Project (CRP) on Optimization of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plants (FUWAC, 2006-2009). It provides an overview of the results of the investigations into the current state of water chemistry practice and concerns in the primary circuit of water cooled power reactors including: corrosion of primary circuit materials; deposit composition and thickness on the fuel; crud induced power shift; fuel oxide growth and thickness; radioactivity buildup in the reactor coolant system (RCS). The FUWAC CRP is a follow-up to the DAWAC CRP (Data Processing Technologies and Diagnostics for Water Chemistry and Corrosion Control in Nuclear Power Plants 2001-2005). The DAWAC project improved the data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (NPPs). With the improved methods for controlling and monitoring water chemistry now available, it was felt that a review of the principles of water chemistry management should be undertaken in the light of new materials, more onerous operating conditions, emergent issues such as CIPS, also known as axial offset anomaly (AOA) and the ageing of operating power plant. In the framework of this CRP, water chemistry specialists from 16 nuclear utilities and research organizations, representing 15 countries, exchanged experimental and operational data, models and insights into water chemistry management. This CD-ROM attached to the printed IAEA-TECDOC includes the report itself, detailed progress reports of three Research Coordination Meetings (RCMs) (Annexes I-III) and the reports and presentations made during the project by the participants.

  13. Classifying hot water chemistry: Application of MULTIVARIATE STATISTICS - R code

    OpenAIRE

    Irawan, Dasapta Erwin; Gio, Prana Ugiana

    2016-01-01

    The following R code was used in this paper "Classifying hot water chemistry: Application of MULTIVARIATE STATISTICS" authors: Prihadi Sumintadireja1, Dasapta Erwin Irawan1, Yuano Rezky2, Prana Ugiana Gio3, Anggita Agustin1

  14. Classifying hot water chemistry: Application of MULTIVARIATE STATISTICS

    OpenAIRE

    Sumintadireja, Prihadi; Irawan, Dasapta Erwin; Rezky, Yuanno; Gio, Prana Ugiana; Agustin, Anggita

    2016-01-01

    This file is the dataset for the following paper "Classifying hot water chemistry: Application of MULTIVARIATE STATISTICS". Authors: Prihadi Sumintadireja1, Dasapta Erwin Irawan1, Yuano Rezky2, Prana Ugiana Gio3, Anggita Agustin1

  15. Electrochemical potential measurements under simulated BWR water chemistry conditions

    International Nuclear Information System (INIS)

    Laboratory studies have been performed to investigate the stainless steel corrosion potential under simulated BWR coolant chemistry conditions. In addition to dissolved oxygen and hydrogen, test parameters also included chemical additives, metallic ions and hydrogen peroxide at various concentrations. The effect of water flow velocity was also investigated under various water chemistry conditions. The details of test results have been described elsewhere, and the highlights of the investigation are summarized in this paper. (J.P.N.)

  16. Simulation of electronic circuit sensitivity towards humidity using electrochemical data on water layer

    DEFF Research Database (Denmark)

    Joshy, Salil; Verdingovas, Vadimas; Jellesen, Morten Stendahl;

    2015-01-01

    the effect on circuit and PCBA (printed circuit board assembly) layout design. This paper elucidates a methodology for analyzing the sensitivity of an electronic circuit based on parasitic circuit analysis using data on electrical property of the water layer formed under humid as well as contaminated......Climatic conditions like temperature and humidity have direct influence on the operation of electronic circuits. The effects of temperature on the operation of electronic circuits have been widely investigated, while the effect of humidity and solder flux residues are not well understood including...

  17. Water Chemistry Section: progress report (1981-82)

    International Nuclear Information System (INIS)

    The activities of the Water Chemistry Section of the Bhabha Atomic Research Centre (BARC), Bombay, during the years 1981 and 1982 are reported in the form of individual summaries. The research activities of the Section cover the following areas: (1) chemistry and thermodynamics of nuclear materials, (2) crystal structure of organo-metallic complexes using X-ray diffraction, (3) thermophysical and phase transition studies, (4) solid state chemistry and thermochemical studies, (5) water and steam chemistry of heavy water plants and phwr type reactors, and (6) uranium isotope exchange studies. A survey is also given of: (i) the Section's participation in advisory and consultancy services in nuclear and thermal power stations, (ii) training activities, and (iii) assistance in chemical analysis by various techniques to other units of BARC and outside agencies. A list of publications and lectures by the staff during the report period is included. (M.G.B.)

  18. Research loops for the water chemistry, corrosion and crud depositing after DECO

    International Nuclear Information System (INIS)

    Reliability of nuclear fuel and radiation fields surrounding primary systems is an important aspect of overall nuclear reactor safety. Corrosion product (crud) deposition on fuel surface has implications for fuel performance through heat transfer and local chemistry modifications. It is important to pay attention to the studies of organic substance behaviour in the circuit, especial in light of the influence of decontamination on the corrosive behaviour of materials and on crud deposition on fuel. Therefore, further research is still needed. The LVR-15 reactor is an important facility, which serves for research into nuclear generating station materials and water chemistry. The main goal of the reactor's facilities is to model conditions that are as close as possible to real conditions, and thus secure the reproducibility and utilization of measured values. Experience that has been gained during the operation of research loops at NRI (RVS-3, RVS-4, Zinc loop) is now used as water chemistry guidelines base ground for the Czech NPPs. Together with the experiences from fuel inspection equipment at the Temelin NPP; NRI has perfect tools for studying and improving of VVER water chemistry regimes

  19. Supercritical water loop design for corrosion and water chemistry tests under irradiation

    International Nuclear Information System (INIS)

    An experimental loop operating with water at supercritical conditions (25MPa, 600 .deg. C in the test section) is designed for operation in the research reactor LVR-15 in UJV Rez, Czech Republic. The loop should serve as an experimental facility for corrosion tests of materials for in-core as well as out-of-core structures, for testing and optimization of suitable water chemistry for a future HPLWR and for studies of radiolysis of water at supercritical conditions, which remains the domain where very few experimental data are available. At present, final necessary calculations (thermalhydraulic, neutronic, strength) are being performed on the irradiation channel, which is the most challenging part of the loop. The concept of the primary and auxiliary circuits has been completed. The design of the loop shall be finished in the course of the year 2007 to start the construction, out-of-pile testing to verify proper functioning of all systems and as such to be ready for in-pile tests by the end of the HPLWR Phase 2 European project by the end of 2009

  20. Water chemistry of small reservoir catchments in central Tunisia

    OpenAIRE

    Montoroi, Jean-Pierre; GRUNBERGER, OLIVIER; Nasri, S

    1999-01-01

    Numerous small hill reservoirs have been constructed in Tunisia since the early 1990's. The water chemistry of a representative small reservoir catchment was investigated to elucidate water-soil-rock interactions. The groundwater and surface water of the calcareous and marly watershed were characterizes by field chemical investigations and pedological observations. The reservoir water was alkaline, with a low concentration, highly oxygenated and weakly carbonated while the groundwater was neu...

  1. Two decades of experience with steam-water chemistry maintenance of fast breeder test reactor

    International Nuclear Information System (INIS)

    Fast Breeder Test Reactor (FBTR) at Kalpakkam is a 40 MWt, loop type, sodium cooled fast reactor. The fission heat generated in the core is extracted by primary sodium circuit and the thermal energy is transferred to non-radioactive liquid sodium in the secondary circuit which in turn, heats Once Through-type shell and tube counter current Steam Generator (OTSG) for producing super heated steam at 480 °C and 125 kg/cm2. This secondary circuit is provided to avoid the ingress of hydrogenous materials and pressure surges reaching the core in the event of SG tube leak. Corrosion related problems are very less in the sodium circuits due to the absence of electrochemical reaction. The OTSG consists of four modules each of 12.5 MWt rating. OTSG was chosen due to its higher thermal efficiency and lesser inventory of steam/water in OTSG as it reduces the severity of sodium-water reaction, in case of tube leak. From the point of view of corrosion and deposition, the chemistry specifications are more stringent for OTSG than those of drum type boilers because 100 % conversion of feed water into steam takes place in OTSG. The chemistry requirements are achieved by providing ion exchange resin based online condensate polishing to remove ionic and suspended impurities. Dissolved Oxygen and pH are maintained by all volatile treatment (AVT) using hydrazine and ammonia respectively. Being a test reactor, a dump condenser with 100 % steam dump facility with cupro-nickel tubes is available for uninterrupted reactor operation during the non-availability of turbine. Regenerative feed heating by the exhausted steam from the turbine is also available to stage heaters and deaerator. Efficient water chemistry control plays important role in minimizing corrosion related failures of steam generator tubes and ensuring steam generator tube integrity. This paper describes the operational difficulties such as premature exhaustion of CPU, impurity pick up from the system, silica excursion

  2. Water chemistry of the JMTR IASCC irradiation loop system

    International Nuclear Information System (INIS)

    Irradiation assisted stress corrosion cracking (IASCC) is recognized as an important degradation issue of the core-internal material for aged Boiling Water Reactors (BWRs). Therefore, irradiation loop system has been developed and installed in the Japan Materials Testing Reactor to perform the IASCC irradiation test. In the IASCC irradiation test, water chemistry of irradiation field is one of the most important key parameters because it affects initiation and propagation of cracks. This paper summarizes the measurement and evaluation method of water chemistry of IASCC irradiation loop system. (author)

  3. Behavior of stainless steels in pressurized water reactor primary circuits

    Science.gov (United States)

    Féron, D.; Herms, E.; Tanguy, B.

    2012-08-01

    Stainless steels are widely used in primary circuits of pressurized water reactors (PWRs). Operating experience with the various grades of stainless steels over several decades of years has generally been excellent. Nevertheless, stress corrosion failures have been reported in few cases. Two main factors contributing to SCC susceptibility enhancement are investigated in this study: cold work and irradiation. Irradiation is involved in the stress corrosion cracking and corrosion of in-core reactor components in PWR environment. Irradiated assisted stress corrosion cracking (IASCC) is a complex and multi-physics phenomenon for which a predictive modeling able to describe initiation and/or propagation is not yet achieved. Experimentally, development of initiation smart tests and of in situ instrumentation, also in nuclear reactors, is an important axis in order to gain a better understanding of IASCC kinetics. A strong susceptibility for SCC of heavily cold worked austenitic stainless steels is evidenced in hydrogenated primary water typical of PWRs. It is shown that for a given cold-working procedure, SCC susceptibility of austenitic stainless steels materials increases with increasing cold-work. Results have shown also strong influences of the cold work on the oxide layer composition and of the maximum stress on the time to fracture.

  4. Water chemistry control to meet the advanced design and operation of light water reactors

    International Nuclear Information System (INIS)

    Water chemistry control is one of the key technologies to establish safe and reliable operation of nuclear power plants. The road maps on R and D plans for water chemistry of nuclear power systems in Japan have been proposed along with promotion of R and D related water chemistry improvement for the advanced application of light water reactors (LWRs). The technical trends were divided into four categories, dose rate reduction, structural integrity, fuel integrity and radioactive waste reduction, and latest technical break through for each category was shown for the advanced application of LWRs. At the same time, the technical break through and the latest movements for regulation of water chemistry were introduced for each of major organizations related to nuclear engineering in the world. The conclusions were summarized as follows; 1. Water chemistry improvements might contribute to achieve the advanced application of LWRs, while water chemistry should be often changed to achieve the advanced application of LWRs. 2. Only one solution for water chemistry control was not obtained for achieving the advanced application of LWRs, but miscellaneous solutions were possible for achieving one. Optimal water chemistry control was desired for having the good practices for satisfying multi-targets at the same time and it was much affected by the plant unique systems and operational history. 3. That meant it was difficult to determine water chemistry regulation targets for achieving application of LWRs but it was necessary to prepare suitable guideline for good achievement of application of LWRs. That meant the guideline should be recommendation for good practice in the plant. 4. The water chemistry guide line should be modified along with progress of plant operation and water chemistry and related technologies. (author)

  5. Monitoring leakages from the primary circuit of a pressurized water nuclear reactor

    International Nuclear Information System (INIS)

    The primary coolant comprises the vessel, the primary part of steam generators, pipes, the pressurizer, and different reservoirs. One auxiliary circuit at least, including a reservoir such as the chemical and volumetric control circuit, is connected to the primary circuit. The primary circuit and the control circuit, excluding the reservoirs, are determined as a group of elementary volumes. At fixed intervals of time, or step, the mass of water in each of the elementary volumes and in each reservoir is determined from pressure, temperature and level measurements, then, adding them, the total mass is obtained. Over a period of time corresponding to a number of steps and in the course of at least one step, the mean mass of water in the primary circuit is calculated, the difference in value between two successive steps representing the leakage from the primary circuit. The invention applies more particularly to reactors with three or four loops

  6. Contribution of water chemistry and fish condition to otolith chemistry: comparisons across salinity environments.

    Science.gov (United States)

    Izzo, C; Doubleday, Z A; Schultz, A G; Woodcock, S H; Gillanders, B M

    2015-06-01

    This study quantified the per cent contribution of water chemistry to otolith chemistry using enriched stable isotopes of strontium ((86) Sr) and barium ((137) Ba). Euryhaline barramundi Lates calcarifer, were reared in marine (salinity 40), estuarine (salinity 20) and freshwater (salinity 0) under different temperature treatments. To calculate the contribution of water to Sr and Ba in otoliths, enriched isotopes in the tank water and otoliths were quantified and fitted to isotope mixing models. Fulton's K and RNA:DNA were also measured to explore the influence of fish condition on sources of element uptake. Water was the predominant source of otolith Sr (between 65 and 99%) and Ba (between 64 and 89%) in all treatments, but contributions varied with temperature (for Ba), or interactively with temperature and salinity (for Sr). Fish condition indices were affected independently by the experimental rearing conditions, as RNA:DNA differed significantly among salinity treatments and Fulton's K was significantly different between temperature treatments. Regression analyses did not detect relations between fish condition and per cent contribution values. General linear models indicated that contributions from water chemistry to otolith chemistry were primarily influenced by temperature and secondly by fish condition, with a relatively minor influence of salinity. These results further the understanding of factors that affect otolith element uptake, highlighting the necessity to consider the influence of environment and fish condition when interpreting otolith element data to reconstruct the environmental histories of fish. PMID:26033292

  7. Chemistry control strategies for a supercritical water-cooled reactor

    International Nuclear Information System (INIS)

    The long-term viability of any Generation IV Supercritical Water-cooled Reactor (SCWR) concept depends on the ability of reactor designers and operators to predict and control water chemistry to minimize corrosion and corrosion product transport. Currently, SCWR material testing is being carried out using a limited range of water chemistries to establish the dependencies of the corrosion behavior on parameters such as water temperature and dissolved oxygen concentration. Once a final suite of candidate alloys is identified, more detailed, longer term testing will be needed under water chemistry regimes expected to be used in the SCWR. Prior to these tests, it will be necessary to identify proposed water chemistry regimes for the SCWR, and provide expected ranges for the key parameters. The direct-cycle design proposed for various SCWR concepts take advantage of the extensive operating experience world-wide of fossil-fired SCW power plants. Conceptually, the SCWR replaces the fossil-fired boiler with the reactor core (pressure vessel or pressure tube); the concept is broadly similar to that of a boiling water reactor. Current fossil-fired SCW power plants use either an all-volatile treatment or oxygenated water treatment for the feedwater systems. While the optimal water chemistry for a SCWR is yet to be determined, the monitored parameters are likely to be the same as those in existing fossil-fired and nuclear power plants: pH; conductivity, and concentrations of O2, H2, additives, impurities, corrosion and activation products. Monitoring will be required at many of the same components: feedwater, main 'steam', drains, pump outlets, condenser hotwell, and purification inlets and outlets. This paper outlines the strategy being used to develop a water chemistry regime for a CANDU® SCWR. It describes the key areas identified for chemistry monitoring and control: a) the reactor core, where materials are subjected to irradiation and high temperature, b

  8. Environmental Chemistry: Air and Water Pollution.

    Science.gov (United States)

    Stoker, H. Stephen; Seager, Spencer L.

    This is a book about air and water pollution whose chapters cover the topics of air pollution--general considerations, carbon monoxide, oxides of nitrogen, hydrocarbons and photochemical oxidants, sulfur oxides, particulates, temperature inversions and the greenhouse effect; and water pollution--general considerations, mercury, lead, detergents,…

  9. Par Pond Fish, Water, and Sediment Chemistry

    International Nuclear Information System (INIS)

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond

  10. Mapping the water chemistry of the Clyde Basin drainage network

    OpenAIRE

    Bearcock, Jenny; Smedley, Pauline; Everett, Paul; Ander, Louise; Fordyce, Fiona

    2014-01-01

    Mapping the chemistry of stream and river water across the Clyde Basin serves both to characterise the water quality and assess the dominant controls. Surveys of the Clyde drainage network, undertaken between 2003 and 2010, have generated data encompassing rural and urban streams, rivers, and estuarine water. Mapping displays the large spatial variability in chemical composition across the Basin and the varying influences of controls such as rainfall, land cover and geology. They also display...

  11. Water chemistry management during hot functional test

    International Nuclear Information System (INIS)

    To reduce radiation exposure in light water reactor, it is important decrease radioactive corrosion product which is a radiation source. One of the countermeasures is to improve water quality during plant trial operation to form a stable oxide film and to minimize metal release to the coolant at the beginning of commercial operation. This study reviews the optimum water quality conditions to form a chromium rich oxide film during hot functional test (HFT) that is thought to be stable under the PWR condition and reduce the release of Ni that is the source of Co-58, the main radiation source of exposure. (author)

  12. Ground water chemistry and water-rock interaction at Kivetty

    International Nuclear Information System (INIS)

    The geochemistry of the groundwater at one of the investigation areas for nuclear waste, Kivetty (Kongingas) in central Finland is evaluated. The hydrogeological data is collected from boreholes drilled down to 1000-m depth into crystalline bedrock. The interpretation is based on groundwater chemistry and isotope data, mineralogical data and the structure and hydrology of the bedrock, using correlation diagrams and thermodynamic calculations (PHREEQE). The hydrogeochemistry and major processes controlling the groundwater chemistry are discussed

  13. High temperature on-line monitoring of water chemistry and corrosion control in water cooled power reactors. Report of a co-ordinated research project 1995-1999

    International Nuclear Information System (INIS)

    This report documents the results of the Co-ordinated Research Project (CRP) on High Temperature On-line Monitoring of Water Chemistry and Corrosion in Water Cooled Power Reactors (1995-1999). This report attempts to provide both an overview of the state of the art with regard to on-line monitoring of water chemistry and corrosion in operating reactors, and technical details of the important contributions made by programme participants to the development and qualification of new monitoring techniques. The WACOL CRP is a follow-up to the WACOLIN (Investigations on Water Chemistry Control and Coolant Interaction with Fuel and Primary Circuit Materials in Water Cooled Power Reactors) CRP conducted by the IAEA from 1986 to 1991. The WACOLIN CRP, which described chemistry, corrosion and activity-transport aspects, clearly showed the influence of water chemistry on corrosion of both fuel and reactor primary-circuit components, as well as on radiation fields. It was concluded that there was a fundamental need to monitor water-chemistry parameters in real time, reliably and accurately. The objectives of the WACOL CRP were to establish recommendations for the development, qualification and plant implementation of methods and equipment for on-line monitoring of water chemistry and corrosion. Chief investigators from 18 organizations representing 15 countries provided a variety of contributions aimed at introducing proven monitoring techniques into plants on a regular basis and filling the gaps between plant operator needs and available monitoring techniques. The CRP firmly demonstrated that in situ monitoring is able to provide additional and valuable information to plant operators, e.g. ECP, high temperature pH and conductivity. Such data can be obtained promptly, i.e. in real time and with a high degree of accuracy. Reliable techniques and sensor devices are available which enable plant operators to obtain additional information on the response of structural materials in

  14. Water chemistry in nuclear power station

    International Nuclear Information System (INIS)

    The nuclear power generation in Japan takes about 30 % of the total generated electric power, and the stable operation and the improvement of the rate of operation are anticipated. In such situation, the water quality control in nuclear power stations aims at the prevention of the corrosion damage of structural materials in the plants, the grasp of the behavior of corrosion products of infinitesimal amount and the countermeasures for reducing them as the important subjects. At the beginning of the operation of LWRs in Japan, stress corrosion cracking and the rise of plant dose rate in BWRs and the corrosion damage of steam generator tubes in PWRs occurred, and the importance of water quality control was recognized. The water quality control standard and the materials for BWRs are shown. In BWRs, the maintenance of the purity of water is the primary subject. The quantity of dissolved oxygen is properly adjusted, and the reduction of generation and removal of iron crud are carried out. Also the water quality control standard and the materials for PWRs are shown. In the primary system, the concentrations of boric acid and lithium hydroxide are controlled, and the pH of coolant is an adjustment factor. In the secondary system, all volatile treatment and condensate desalting equipment are used. (Kako, I.)

  15. Water chemistry of Kori nuclear power plant

    International Nuclear Information System (INIS)

    An analysis and investigation were performed on the data connected with water quality control at Kori No. 1 plant, during commercial operation, from Apr. to Oct. 1978. Contents of ammonia contained in steam generator samples in Apr. and Sep. were exceeding the control value recommended by Westingouse, but contents of another analysis items were satisfied with Westinghouse's value. Ammonia being determental to materials of PWR is produced by thermal decomposition of hydrazine added in order to decrease dissolved oxygen. Therefore, the factors considered to minimize dissolved oxygen content as well as behaviour of ammonia in secondary coolant were investigated. Furthermore, brief discussion was made on establishing of polishing plant, establishment of water analysis method, establishing of on-line recorder and its normal operation to control water quality efficiently, and designs for construction of autoclave and pot boiler to study corrosion phenomena. (author)

  16. Drainage water chemistry in geochemically contrasting catchments

    Czech Academy of Sciences Publication Activity Database

    Krám, Pavel; Myška, Oldřich; Čuřík, J.; Veselovský, F.; Hruška, Jakub

    Brno : Global change research centre, Academy of Sciences of the Czech Republic, v. v. i, 2013 - (Stojanov, R.; Žalud, Z.; Cudlín, P.; Farda, A.; Urban, O.; Trnka, M.), s. 173-177 ISBN 978-80-904351-8-6. [Global Change and Resilience. Brno (CZ), 22.05.2013-24.05.2013] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : granite * amphibolite * serpentinite * Norway spruce * soil water * stream water * acidification * weathering Subject RIV: EH - Ecology, Behaviour

  17. Does stream water chemistry reflect watershed characteristics?

    Czech Academy of Sciences Publication Activity Database

    Chuman, Tomáš; Hruška, Jakub; Oulehle, Filip; Gürtlerová, P.; Majer, V.

    2013-01-01

    Roč. 185, č. 7 (2013), s. 5683-5701. ISSN 0167-6369 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : Anions * Cations * Land cover * Water quality * Geochemical reactivity * Czech Republic Subject RIV: EH - Ecology, Behaviour Impact factor: 1.679, year: 2013

  18. Hydrological Controls on Water Chemistry that Supports Freshwater Mussel Populations

    Science.gov (United States)

    Prestegaard, K. L.

    2012-12-01

    Native freshwater mussel species ranges and population sizes have been declining throughout N. America. Due to their sedentary nature, adult mussels are vulnerable to both local habitat changes (often associated with land-use changes, contaminants, and biological invaders) and to climate changes that can alter river flow regimes, bed stability, and water chemistry. The purpose of this study is to examine the relationship between water chemistry and hydrological events in rivers that support native mussel populations. USGS ion concentration and water quality (pH, temperature, conductivity) data were used to calculate saturation indices for aragonite. For some sites, electrical conductivity was highly correlated with calcium and bicarbonate concentrations and could be used to estimate concentrations when ion chemistry was not measured. Continuous water quality data from datasondes could thus be used to evaluate saturation indices for aragonite on a daily basis for 10-15 year periods. For the Delaware River, which has relatively few carbonate rocks in its watershed, tributary aragonite saturation tended to reflect local geological conditions. The lower main stem of the river integrates the water chemistry of the basin and also responds to climatic conditions. The lower Delaware supports aragonite precipitation approximately 50 days per year, with considerable inter-annual variability. During most years, aragonite precipitation could occur during both the spring and late summer periods, but years with heavy spring rains rather than snowmelt shifts aragonite precipitation to late summer periods. In 2011 when several major tropical storms hit the Delaware basin, streamflow was too dilute for aragonite precipitation for most of the summer period. These data suggest that hydrological changes associated with climatic changes may influence the water chemistry and affect the suitability of some rivers as mussel habitat.

  19. Dynamic combinatorial chemistry with diselenides and disulfides in water

    DEFF Research Database (Denmark)

    Rasmussen, Brian; Sørensen, Anne; Gotfredsen, Henrik;

    2014-01-01

    Diselenide exchange is introduced as a reversible reaction in dynamic combinatorial chemistry in water. At neutral pH, diselenides are found to mix with disulfides and form dynamic combinatorial libraries of diselenides, disulfides, and selenenylsulfides. This journal is © the Partner Organisations...

  20. Proceedings of the water chemistry and materials performance conference

    International Nuclear Information System (INIS)

    The proceedings contain 11 papers dealing with primary and secondary side water chemistry in CANDU reactors, with the associated problems of activity transport and steam generator corrosion, and also with the use of decontaminating solutions. The individual papers have been abstracted separately

  1. The impact of water radiolysis on the ECP in PWR primary coolant circuits

    International Nuclear Information System (INIS)

    A chemistry/radiolysis/mixed potential model has been developed to calculate radiolytic species concentrations and corrosion potential at closely spaced points around the primary coolant circuit of a pressurized water reactor (PWR). The pH, as a function of temperature of the coolant, is calculated at each point of the primary loop using a chemical equilibrium model. The radiolysis model is a modified version of the code developed to previously model the radiochemistry and corrosion properties of Boiling Water Reactor (BWR) primary coolant circuits by Macdonald. The modifications include additional species and reactions taken from other models for describing the radiolysis of water. The model offers the possibility of choosing up to 48 different sets of reactions when calculating species concentrations. The set of 34 reactions used to calculate the ECP in a BWR by Macdonald was completed up to 48 reactions. Six different modified subsets were obtained from that original set as indicated. In this paper, we explore (1) the impact of choosing different sets in the calculation of the ECP and (2) the impact on the ECP calculations when 14 additional authors' data for the 48 reactions were used (in addition to the original 34 reaction sets used by Macdonald and the set of 48 reactions obtained by adding 14 additional reactions to the original 34 reactions set; data on the 48 reactions from the 14 authors was compiled and shown in Table 4. The radiolytic yields for the primary species (14 different species as this paper we selected to work with the set shown in Table 2. It is important to recognize the dictions due to the fact that we currently have electrochemical kinetic data for only a limited number of redox species (H2, O2, H2O2) on Type 304 SS, so only this substrate could be modeled with respect to the ECP. However, it is believed that Type 304 SS serves as a good analog for other stainless steels and, perhaps, for nickel-based alloys, such as Alloys 600 and 718

  2. Water Chemistry and Clad Corrosion/Deposition Including Fuel Failures. Proceedings of a Technical Meeting

    International Nuclear Information System (INIS)

    Corrosion is a principal life limiting degradation mechanism in nuclear steam supply systems, particularly taking into account the trends in increasing fuel burnup, thermal ratings and cycle length. Further, many plants have been operating with varying water chemistry regimes for many years, and issues of crud (deposition of corrosion products on other surfaces in the primary coolant circuit) are of significant concern for operators. At the meeting of the Technical Working Group on Fuel Performance and Technology (TWGFPT) in 2007, it was recommended that a technical meeting be held on the subject of water chemistry and clad corrosion and deposition, including the potential consequences for fuel failures. This proposal was supported by both the Technical Working Group on Advanced Technologies for Light Water Reactors (TWG-LWR) and the Technical Working Group on Advanced Technologies for Heavy Water Reactors (TWG-HWR), with a recommendation to hold the meeting at the National Nuclear Energy Generating Company ENERGOATOM, Ukraine. This technical meeting was part of the IAEA activities on water chemistry, which have included a series of coordinated research projects, the most recent of which, Optimisation of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC) (IAEATECDOC-1666), concluded in 2010. Previous technical meetings were held in Cadarache, France (1985), Portland, Oregon, USA (1989), Rez, Czech Republic (1993), and Hluboka nad Vltavou, Czech Republic (1998). This meeting focused on issues associated with the corrosion of fuel cladding and the deposition of corrosion products from the primary circuit onto the fuel assembly, which can cause overheating and cladding failure or lead to unplanned power shifts due to boron deposition in the clad deposits. Crud deposition on other surfaces increases radiation fields and operator dose and the meeting considered ways to minimize the generation of crud to avoid

  3. Primary water chemistry for NPP with VVER-TOI

    International Nuclear Information System (INIS)

    Nowadays within the framework of development of the nuclear power industry in Russia the VVER-TOI reactor is under designing (Standard optimized design). The given design provides for improvement of operation safety level, of technical-economic, operational and load-follow characteristics, and for the raise of competitive capacity of reactor plant and NPP as a whole. In VVER-TOI reactor plant design the primary water chemistry has been improved considering operation experience of VVER reactor plants and a possibility of RP operation under load-follow modes from the viewpoint of meeting the following requirements: - suppression of generation of oxidizing radiolytic products under power operation; - assurance of corrosion resistance of structural materials of equipment and pipelines throughout the NPP design service life; - minimization of deposits on surfaces of the reactor core fuel rods and on heat exchange surface of steam generators; - minimization of accumulation of activated corrosion products; - minimization of the amount of radioactive processing waste. In meeting these requirements an important role is devoted to suppression of generation of oxidizing radiolytic products owing to accumulation of hydrogen in the primary coolant. At NPP with VVER-1000 reactor the ammonia-potassium water chemistry is used wherein the hydrogen accumulation is provided at the expense of ammonia proportioning. Usage of ammonia leads to generation of additional amount of radioactive processing waste and to increased irregularity of maintaining the water chemistry under the daily load-follow modes. In VVER TOI design the primary water chemistry is improved by replacing the proportioning of ammonia with the proportioning of gaseous hydrogen. Different process schemes were considered that provide for a possibility of hydrogen accumulation and maintaining owing to direct proportioning of gaseous hydrogen. The obtained results showed that transition to the potassium water chemistry

  4. Adaptation of Coccolith Calcification to Sea Water Carbonate Chemistry

    Science.gov (United States)

    Ziveri, P.; Langer, G.; Probert, I.; Young, J.

    2008-12-01

    Coccolithophores are major calcifiers and through calcification cause feedbacks to atmospheric CO2 cycling. The formation of CaCO3 in seawater, in fact, causes a shift of the carbonate system towards CO2, which in turn affects atmosphere / ocean CO2 exchange. A change in marine calcification provides a concomitant feedback in organic carbon export and would lead to a change in the drawdown of atmospheric CO2. Coccolithophore culture experiments and field observations showed controversial results regarding the response of calcification to high CO2. The three strains of Emiliania huxleyi (the most abundant living coccolithophore species) tested so far show both increased and decreased calcification at high CO2 levels (lower pH). Living E. huxleyi is known to have a large variability in both size and carbonate content. The hypothesis that we want to test in this work is the importance of adaptation of calcification to the seawater carbonate chemistry where coccolithophores calcify. We selected 4 strains of E. huxleyi maintained at the Roscoff culture collection, collected from different oceanographic settings with different carbon speciation. The selected strains are collected from environments with very different water carbonate chemistry and they have different carbonate mass. They have been experimentally grown at different CO2 levels to test the strain calcification response to sea water carbonate chemistry. . With these experiments we test the importance of the calcification strain adaptation to carbonate chemistry. Size and possibly different responses to carbonate chemistry variations will also be discussed.

  5. Data processing technologies and diagnostics for water chemistry and corrosion control in nuclear power plants (DAWAC). Additional information. Report of a coordinated research project 2001-2005

    International Nuclear Information System (INIS)

    The CD-ROM attached to the printed version of TECDOC 1505 'Data Processing Technologies and Diagnostics for Water Chemistry and Corrosion Control in Nuclear Power Plants (DAWAG)' includes the report itself, detailed progress reports of three research coordination meetings (Annexes I-III) and the final country reports. This publication provides information on the current status and development trends in monitoring, diagnostics and control of water chemistry and corrosion of core and primary circuit materials in water cooled power reactors. It summarizes the results of an IAEA Coordinated Research Project and focuses on the methods for development, qualification and implementation of water chemistry expert systems at nuclear power plants. These systems are needed to have full benefit from using on-line sensors in real time mode when sensor signals, and other chemistry and operational data, are collected and continuously analysed with data acquisition and evaluation software. Technical knowledge was acquired in water chemistry control techniques (grab sampling, on-line monitoring, data collecting and processing, etc), plant chemistry and corrosion diagnostics, plant monitoring (corrosion, chemistry, activity)and plant chemistry improvement (analytical models and practices). This publication covers contributions from leading experts in water chemistry/corrosion, representing organizations from 16 countries with the largest nuclear capacities

  6. Geothermal energy : settlement and water chemistry in Cork, Ireland

    OpenAIRE

    Hemmingway, Phil; Long, Michael

    2011-01-01

    Detailed analysis of potential water chemistry and settlement issues associated with the installation of open-loop geothermal systems is infrequently carried out. This has led to the failure of several previously installed systems. Chemical analysis of water extracted from beneath the Cork docklands, Ireland has been performed by the authors in order to assess the suitability of the area for the exploitation of open-loop geothermal energy. The possibility of settlement induced by pum...

  7. Modeling UTLS water vapor: Transport/Chemistry interactions

    International Nuclear Information System (INIS)

    This thesis was initially meant to be a study on the impact on chemistry and climate from UTLS water vapor. However, the complexity of the UTLS water vapor and its recent changes turned out to be a challenge by it self. In the light of this, the overall motivation for the thesis became to study the processes controlling UTLS water vapor and its changes. Water vapor is the most important greenhouse gas, involved in important climate feedback loops. Thus, a good understanding of the chemical and dynamical behavior of water vapor in the atmosphere is crucial for understanding the climate changes in the last century. Additionally, parts of the work was motivated by the development of a coupled climate chemistry model based on the CAM3 model coupled with the Chemical Transport Model Oslo CTM2. The future work will be concentrated on the UTLS water vapor impact on chemistry and climate. We are currently studying long term trends in UTLS water vapor, focusing on identification of the different processes involved in the determination of such trends. The study is based on natural as well as anthropogenic climate forcings. The ongoing work on the development of a coupled climate chemistry model will continue within our group, in collaboration with Prof. Wei-Chyung Wang at the State University of New York, Albany. Valuable contacts with observational groups are established during the work on this thesis. These collaborations will be continued focusing on continuous model validation, as well as identification of trends and new features in UTLS water vapor, and other tracers in this region. (Author)

  8. Study of water radiolysis in relation with the primary cooling circuit of pressurized water reactors

    International Nuclear Information System (INIS)

    This memorandum shows a fundamental study on the water radiolysis in relation with the cooling primary circuit of PWR type reactors. The water of the primary circuit contains boric acid a soluble neutronic poison and also hydrogen that has for role to inhibit the water decomposition under radiation effect. In the aim to better understand the mechanism of dissolved hydrogen action and to evaluate the impact of several parameters on this mechanism, aqueous solutions with boric acid and hydrogen have been irradiated in a experimental nuclear reactor, at 30, 100 and 200 Celsius degrees. It has been found that, with hydrogen, the water decomposition under irradiation is a threshold phenomenon in function of the ratio between the radiation flux '1' B(n, )'7 Li and the gamma flux. When this ratio become too high, the number of radicals is not sufficient to participate at the chain reaction, and then water is decomposed in O2 and H2O2 in a irreversible way. The temperature has a beneficial part on this mechanism. The iron ion and the copper ion favour the water decomposition. (N.C.)

  9. Linking variability in brain chemistry and circuit function through multimodal human neuroimaging

    DEFF Research Database (Denmark)

    Fisher, Patrick M; Hariri, A R

    2012-01-01

    assay in vivo regional brain chemistry and function, respectively. Typically, these neuroimaging modalities are implemented independently despite the capacity for integrated data sets to offer unique insight into molecular mechanisms associated with brain function. Through examples from the serotonin...

  10. Corrosion Products Identification at Normal Water and Hydrogen Water Chemistry in Boiling Water Reactors

    International Nuclear Information System (INIS)

    The corrosion products sampled from condensate and feedwater systems of boiling water reactors (BWRs) at normal water chemistry (NWC) and hydrogen water chemistry (HWC) operating condition were analyzed with dissolution and instrumental simulation methods. The crystallite and amorphous of iron oxides were separated by means of dissolving method with appropriate chemical solution. The iron oxide composition and content were analyzed by X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectrometer (ICP-AES) in this study. The insoluble iron oxides were obtained in influent and effluent of condensate demineralizer comprised mostly crystalline structure of hematite, magnetite and non-crystallite form of amorphous at NWC and HWC environments. Both goethite and lepidocrocite compositions are of minor importance in feed water system. Crystallite and amorphous compositions in the samples will be calculated from the new developing dissolution method. The crystalline phase of corrosion products are varied with water chemistry conditions in BWRs. The oxide characterization of system corrosion products includes compositions, morphology and particle size can effectively provide the ways of solving crud removal problem in different condition for the performance of condensate demineralizer. The feasibility of identifying other iron oxides and hydroxides in corrosion products is briefly discussed and the mechanisms of iron oxide formation formed around BWR piping will also be shown in detail in this report. Moreover, it will be figured out the properties of radioactive corrosion products growing in different operation periods. The results can also assist in plant units to improve the crud reduction countermeasures and to optimize the system water chemistry. (authors)

  11. Improved primary water chemistry control of PWR plant in Japan

    International Nuclear Information System (INIS)

    Elevated pH operation to the pH value of 7.3 at 285degC is known to be effective for the reduction of radiation source in the primary water system of PWRs. A research project was started in 1989 and concluded in 1996 to study and verify the optimum pH and/or Li concentration from the viewpoint of radiation source reduction and materials integrity under improved water chemistry. This research project is sponsored by the Ministry of International Trade and Industries (MITI) in Japan and has two programs; high pH and high Li. The high Li program was conducted to establish the optimum Li concentration for the high boron concentration region (1100 - 1800 ppm) of the high burn up operation. In this paper, we shall discuss radiation source behavior under high pH conditions and PWSCC (Primary Water Stress Corrosion Cracking) susceptibility of materials with change of primary water chemistry conditions and the improved water chemistry control based on these tests results. (author)

  12. Radiation chemistry in ammonia-water ices

    International Nuclear Information System (INIS)

    We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2, NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (∼97% destroyed) after a fluence of 1016 ions/cm2. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2, which are seen to be ejected from the ice at all temperatures.

  13. Modifications in secondary circuit chemistry of Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    The CNA I secondary circuit presents, by design, some materials which are difficult to be compatible from the corrosion point of view. The presence of Cu alloys limits the use of ammonia (or products that for decomposition generates it) as pH regulator substance which would be convenient to minimize the corrosion processes. The pH limit value in agreement with the operative experience is 9.2. This value is below the one required to minimize the effects of corrosion on the carbon steel, which is present inside the secondary circuit with a considerable exposed area and under hydrodynamic and hydrothermal conditions that favor those processes. This corrosive effect diminishes below certain limits, i. d. if the pH value is increased. The realization of this study involves three stages at least: a)- Independent measurements and description of the circuit current state; b)- Laboratory experiences of the possible alternatives into replace NH3 as alkaline agent and to provide better control of the corrosion process, on Cu alloys as well as steel alloys; c)- Plant implementations of the actions that are feasible from the point of view of power station operation, in such a way that in the secondary circuit it minimizes the presence of ammonia in the vapor phase and at the same time, the possibility of increasing the pH of the liquid phase, to diminish the corrosion phenomena of carbon steel. (author)

  14. Apparatus for ground water chemistry investigations in field caissons

    International Nuclear Information System (INIS)

    Los Alamos is currently in its second season of ground water chemistry and hydrology experimentation in a field facility that incorporates clusters of six, 3-meter-diameter by 6-meter-deep, soil-filled caissons and required ancillaries. Initial experience gained during the 1983 field season indicated the need for further development of the technology of this type of experimentation supporting hydrologic waste management research. Uniform field application of water/matrix solutions to the caisson, matrix and tracer solution blending/storage, and devices for ground water sampling are discussed

  15. Deflection circuit monitors force on object under water

    Science.gov (United States)

    Roller, R.; Yaroshuk, N.

    1968-01-01

    Capsule containing samples for radiation testing is guided under through a seal to an exact position within a nuclear reactor. A Linear Variable Differential Transformer /LVDT/ flexplate deflection circuit monitors the force on the capsule as it is positioned within the reactor.

  16. Ground water flow analysis of potential low level radioactive waste disposal sites using electrical circuit analogies

    International Nuclear Information System (INIS)

    The analogy between electrical circuits and ground water flow systems is developed. The analogy previously required an extensive electrical network to obtain the desired results. This paper deals with adapting the analogy to a computer based electrical circuit analysis program. The application of the analogy is then demonstrated through a preliminary ground water modeling of a proposed Low-Level Radioactive Waste Disposal Site in Illinois, USA. (orig.)

  17. Modelling of Transport of Radioactive Substances in the Primary Circuit of Water Cooled Reactors

    International Nuclear Information System (INIS)

    coordinated research project (CRP) was proposed to determine the accuracy of existing computer codes and to identify how they could be improved through application of this body of work. Specifically, the CRP was expected to: - Build a database for selected pressurized water reactor (PWR) plants that would contain the design information suitable for their description within a computer code, as well as give the operating history of the plant, which would include the water chemistry data over several refuelling cycles; - Show the contamination of selected out-of-core surfaces such as circulating loops and steam generator channel heads versus operating history and compare the prediction of surface contamination versus time from modern radioactivity transport codes with actual plant data in a blind benchmarking exercise; - Determine how current codes, as well as new ones, could be improved and encourage the development of accurate new codes in Member States using the recommendations from the present work. This report uses as its basis the results of this CRP on 'Modelling of Transport of Radioactive Substances in the Primary Circuit of Water Cooled Reactors', which was conducted over the period 1996-2001 for PWR type reactors. The report also describes the significant progress demonstrated in this field in the period that followed.

  18. Determining water chemistry conditions in nuclear reactor coolants

    International Nuclear Information System (INIS)

    The chemistry of the process and coolant systems in water-cooled nuclear reactors is tightly controlled to minimise material degradation and, for some systems, to regulate reactor power. Tight control entails monitoring the systems and making appropriate adjustments. Online monitoring can be utilised where instruments are available but otherwise samples must be taken and measurements made offline. This paper reviews the current technologies for monitoring and sampling. (author)

  19. Activity of Water Chemistry Division of the Atomic Energy Society of Japan

    International Nuclear Information System (INIS)

    A water chemistry group in Japan started in 1982 as a special committee of the Atomic Energy Society of Japan (AESJ). In 2007 the committee has been upgraded as Water Chemistry Division. Current status of the Water Chemistry Division is briefly summarized. (author)

  20. Impacts of simulated drought on pore water chemistry of peatlands

    International Nuclear Information System (INIS)

    Northern peatlands are increasingly threatened by climate change and industrial activities. This study examined the impact of simulated droughts on pore water chemistry at six peatlands in Sudbury, Ontario, that differ in copper (Cu), nickel (Ni) and cobalt (Co) contamination, including a site that had been previously limed. All sites responded similarly to simulated drought: pore water pH declined significantly following the 30 day drought and the decline was greater following the 60 day drought treatment. The decline in pore water pH was due to increasing sulphate concentrations, whereas nitrate increased more in the 60 day drought treatment. Decreases in pH were accompanied by large increases in Ni and Co that greatly exceeded provincial water quality guidelines. In contrast, dissolved organic carbon (DOC) concentrations decreased significantly following drought, along with concentrations of Cu and Al, which are strongly complexed by organic acids. -- Highlights: • Assessed impact of simulated 30 and 60 day droughts on peatland pore water chemistry. • Release of SO4 and NO3 induces peatland acidification. • Release of Ni and Co increases with drought duration. • Dissolved organic carbon decreases with drought along with Cu and Al. • Historical liming does not greatly reduce drought impact. -- Simulated drought acidifies pore water of peatlands and increases Ni and Co but decreases DOC, Cu and Al concentration

  1. PWR-440 water chemistry optimization to reduce AOA effect

    International Nuclear Information System (INIS)

    The pressure drop increase in PWR-440 is mainly caused by the fact that the coolant contains numerous corrosion products, which are generated after decontamination and deposited in the top part of the fuel assembly as well as by coolant nucleate boiling that under standard water chemistry conditions leads to acceleration of corrosion products deposition and coolant radioactivity growth respectively. The modeling of the pressure drop changes were based on standard data of water chemistry, reactor operating characteristics and fundamental thermodynamic parameters to predict the pressure drop growth. The results of the performed research and modeling of the corrosion products mass transfer processes allowed to qualify relative contribution of thermohydraulic and chemical parameters in the processes and to fulfill the activities as follows: To perform power units operation at water chemistry with maximum permissible alkali metals content. To increase the coolant flow rate through the core; to do so, throttling orifices were replaced and canister-shields were removed. To reduce the number of steam generators to be decontaminated to 2 per year in a single power unit. As a result deposits accumulation in fuel assemblies has been minimized and there is no leakage in the fuel element; reactor thermal output limitation has been eliminated. (author)

  2. Corrosion of primary circuits in pressurized water reactors - Historical analysis

    International Nuclear Information System (INIS)

    After an introduction which proposes a simplified description of the PWR operating principles, and discusses some peculiarities of nuclear components, the author presents the characteristics of the heat transfer medium (characteristics, radiolysis efficiency, recombination reactions, and quantification). The next part addresses the uniform corrosion of austenitic materials: generalized or uniform corrosion of austenitic materials and steels (corrosion models, stainless steel corrosion, corrosion in saturated media, elements other than iron in austenitic materials, influence of boron concentration, oxide protection quality, corrosion and release rate). Then, the author addresses the consequences of corrosion in the primary circuit, the stress corrosion of austenitic materials, the corrosion of fuel cans, and the contamination by fission products (origin of fission products in the primary circuit of PWR and their consequences, fission product release mechanisms, diagnosis of sheath status). A chapter briefly addresses BWRs, notably the process of zinc injection. The last chapter proposes an overview of recent evolutions regarding various issues: wall thinning, stress corrosion, generalized corrosion, transport and contamination models, circuit contamination, sheath corrosion

  3. Water Formation and Oxygen Chemistry on Dust Grains

    Science.gov (United States)

    Vidali, Gianfranco; He, Jiao

    Water plays an important role in space. As ice on cold dust grains, it provides the medium for a rich chemistry; in the gas-phase, it gives information on the particular environment it is in. It is understood that the formation of water occurs both in the gas-phase and on grains. While the importance of water formation on dust grain surfaces has been recognized for a long time (1) , it is only recently that laboratory investigations have been undertaken to characterize the network of reactions (2) . Closely connected to this work on water formation, is the study of oxygen chemistry on dust grains. Of particular importance is the characterization of the energetics of adsorption, diffusion and desorption of oxygen-containing molecules. I will present data from recent experiments on the interaction of oxygen and hydroxyls with silicate surfaces and on the formation of water on warm (T>30K) amorphous silicates. Such results provide new values to parameters used in simulation codes of the chemical evolution of interstellar space environments. 1. A.G.G.M Tielens & W. Hagen, Astron. & Astrophys. 114, 245 (1982). 2. G. Vidali, J. Low Temp. Phys. 170,1 (2013). This work is supported by the NSF, Astronomy & Astrophysics Division (Grants No. 0908108 and 1311958), and NASA (Grant No. NNX12AF38G). We thank Dr. J.Brucato of the Astrophysical Observatory of Arcetri for providing the samples used in these experiments.

  4. A robust model for pore-water chemistry of clayrock

    Science.gov (United States)

    Gaucher, E. C.; Tournassat, C.; Pearson, F. J.; Blanc, P.; Crouzet, C.; Lerouge, C.; Altmann, S.

    2009-11-01

    The chemistry of pore water is an important property of clayrocks being considered as host rocks for long-term storage of radioactive waste. It may be difficult, if not impossible, to obtain water samples for chemical analysis from such rocks because of their low hydraulic conductivity. This paper presents an approach for calculating the pore-water compositions of clayrocks from laboratory-measured properties of core samples, including their leachable Cl and SO 4 concentrations and analysed exchangeable cations, and from mineral and cation exchange equilibria based on the formation mineralogy. New core sampling and analysis procedures are presented that reduce or quantify side reactions such as sample oxidation (e.g. pyrite) and soluble mineral dissolution (celestite, SrSO 4) that affect measured SO 4 concentrations and exchangeable cation distributions. The model considers phase equilibria only with minerals that are observed in the formation including the principal clay phases. The model has been used to calculate the composition of mobile pore water in the Callovo-Oxfordian clayrock and validated against measurements of water chemistry made in an underground research laboratory in that formation. The model reproduces the measured, in situ pore-water composition without any estimated parameters. All required parameters can be obtained from core sample analysis. We highlight the need to consider only those mineral phases which can be shown to be in equilibrium with contacting pore water. The consequence of this is that some conceptual models available in the literature appear not to be appropriate for modelling clayrocks, particularly those considering high temperature and/or high pressure detrital phases as chemical buffers of pore water. The robustness of our model with respect to uncertainties in the log K values of clay phases is also demonstrated. Large uncertainties in log K values for clay minerals have relatively small effects on modelled pore-water

  5. The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry Class

    Science.gov (United States)

    Keaffaber, Jeffrey J.; Palma, Ramiro; Williams, Kathryn R.

    2008-01-01

    Water chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. Marine aquaria and their life support systems feature many chemical processes. A life support system consists of the entire recirculation system, as well as the habitat tank and all ancillary…

  6. Water chemistry management of research reactor in JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Yoshijima, Tetsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    The JRR-3M cooling system consists of four systems, namely; (1) primary cooling system, (2) heavy water cooling system, (3) helium system and (4) secondary cooling system. The heavy water is used for reflector and pressurized with helium gas. Water chemistry management of the JRR-3M cooling systems is one of the important subject for the safety operation. The main objects are to prevent the corrosion of cooling system and fuel elements, to suppress the plant radiation build-up and to minimize the generation of radioactive waste. All measured values were within the limits of specifications and JRR-3M reactor was operated with safety in 1996. Spent fuels of JRR-3M reactor are stored in the spent fuel pool. This pool water has been analyzed to prevent corrosion of aluminum cladding of spent fuels. Water chemistry of spent fuel pool water is applied to the prevention of corrosion of aluminum alloys including fuel cladding. The JRR-2 reactor was eternally stopped in December 1996 and is now under decommissioning. The JRR-2 reactor is composed of heavy water tank, fuel guide tube and horizontal experimental hole. These are constructed of aluminum alloy and biological shield and upper shield are constructed of concrete. Three types of corrosion of aluminum alloy were observed in the JRR-2. The Alkaline corrosion of aluminum tube occurred in 1972 because of the mechanical damage of the aluminum fuel guide tube which is used for fuel handling. Modification of the reactor top shield was started in 1974 and completed in 1975. (author)

  7. NRI Position in the Water Chemistry Research and Fuel Inspection for Czech WWER-1000 Reactors

    International Nuclear Information System (INIS)

    Fuel failures and other fuel related issues can have significant operational impacts on nuclear power plants. Some nuclear power plants lost several millions per event to cover replacement power costs and the costs of a fuel reload due to fuel failures. Efforts to increase fuel utilization (longer cycles) and burnup are faced with real technical problems with facilities and components such as facility aging, fuel cladding corrosion, crud deposition and fuel fretting, the transport of activated crud from the active zone to other parts of the primary circuit and the subsequent need for frequent decontamination. While the industry has made substantial progress in reducing the frequency of fuel failures, continued attention to technical gaps impacting fuel reliability is needed. Since first reload, NPP Temelin, together with the fuel vendor, is performing post irradiation inspection on the fuel assemblies. However, the fuel vendor is changing and new plans for the fuel inspection are ready. The report describes past experiences with fuel inspections and repairs at the NPP Temelin and the role of Nuclear Research Institute (NRI) in the future cooperation with the new fuel vendor. In addition, NRI plays an important role in the Czech nuclear research market. The reactor services division carries out material irradiation and radioisotopes research and is involved in water chemistry research for PWR, BWR and WWER reactors and its impact on the crud deposition and fuel reliability. The main experimental loops and their utilization for water chemistry recommendations for Czech NPPs are also presented in paper. (author)

  8. Expert system for diagnostics and status monitoring of NPP water chemistry condition

    International Nuclear Information System (INIS)

    Water chemistry condition (WCC) has been the subject of constant study and improvement up to the present day. It is connected with the presence of a direct relationship between the violation of water chemistry regulation on the one hand and components reliability of the circuit's equipment and cost-effectiveness of their operation on the other. It dictates the necessity to apply different optimization methods in the field of monitoring and use of information analytical and diagnostic systems to assess WCC quality, control and support. LI ''VNIPIET'' employees have, for several years, been developing an expert diagnostic system for supporting WCC and status monitoring of RBMK - reactor NPPs [2]. This system has not only conveniently organized the traditional functions of information acquisition and storage, a complete presentation of information in the form of tables, graphs of a dynamical changes of parameters and formation regular reports, diagnostic functions and issuing recommendations on WCC correction, but it also allows the assessment of confidence in the diagnosis made, relying on a wide range of numerical estimates, which were calculated by the use of expert data, and to make a credible prediction of an existing situation development. (authors)

  9. Expert system for diagnostics and status monitoring of NPP water chemistry condition

    Energy Technology Data Exchange (ETDEWEB)

    Shvedova, M.N.; Kritski, V.G.; Zakharova, S.V.; Benediktov, V.B.; Nikolaev, F.V. [All-Russian Scientific Research and Design Inst. of Complex Power Technology (LI ' VNIPIET), St. Petersburg (Russian Federation)

    2002-07-01

    Water chemistry condition (WCC) has been the subject of constant study and improvement up to the present day. It is connected with the presence of a direct relationship between the violation of water chemistry regulation on the one hand and components reliability of the circuit's equipment and cost-effectiveness of their operation on the other. It dictates the necessity to apply different optimization methods in the field of monitoring and use of information analytical and diagnostic systems to assess WCC quality, control and support. LI ''VNIPIET'' employees have, for several years, been developing an expert diagnostic system for supporting WCC and status monitoring of RBMK - reactor NPPs [2]. This system has not only conveniently organized the traditional functions of information acquisition and storage, a complete presentation of information in the form of tables, graphs of a dynamical changes of parameters and formation regular reports, diagnostic functions and issuing recommendations on WCC correction, but it also allows the assessment of confidence in the diagnosis made, relying on a wide range of numerical estimates, which were calculated by the use of expert data, and to make a credible prediction of an existing situation development. (authors)

  10. In-pile loop experiments in water chemistry and corrosion

    International Nuclear Information System (INIS)

    Methods and techniques used were as follows: (a) Method of polarizing resistance for remote monitoring of instantaneous rate of uniform corrosion. (b) Out-of-pile loop at the temperature 350 degC, pressure 19 MPa, circulation 20 kgs/h, testing time 1000 h. (c) High temperature electromagnetic filter with classical solenoid and ball matrix for high pressure filtration tests. (d) High pressure and high temperature in-pile water loop with coolant flow rate 10 000 kgs/h, neutron flux in active channel 7x1013 n/cm2.s, 16 MPa, 330 degC. (e) Evaluation of experimental results by chemical and radiochemical analysis of coolant, corrosion products and corrosion layer on surface. The results of measurements carried out in loop facilities can be summarized into the following conclusions: (a) In-pile and out-of-pile loops are suitable means of investigating corrosion processes and mass transport in the nuclear power plant primary circuit. (b) In studying transport phenomena in the loop, it is necessary to consider the differences in geometry of the loop and the primary circuit, mainly the ratio of irradiated and non-irradiated surfaces and volumes. (c) In the experimental facility simulating the WWER-type nuclear power plant primary circuit, solid suspended particles of a chemical composition corresponding most frequently to magnetite or nickel ferrite, though with non-stoichiometric composition Mex2+Fe3-x3+O4, were found. (d) Continuous filtration of water by means of an electromagnetic filter removing large particles of corrosion products leads to a decrease in radioactivity of the outer epitactic layer only. The effect of filtration on the inner topotactic layer is negligible

  11. On catholyte application for hydrogen water chemistry in PWR

    International Nuclear Information System (INIS)

    Considering liquid water as a chemical compound with a wide band gap shows that its Redox potential as Fermi level in the band gap is the measurable characteristic of a non-stoichiometric aqueous coolant in recirculation system of PWR. The hypo-stoichiometric state with the negative Redox potential is realized when Fermi level is shifted to the bottom of conduction band. This state can be fixed by the electro-reduced water (catholyte) of the alkaline solution. Then, the hydride anions (H3O-) as proton acceptors and the hydrox-onium radicals (H3O) as electron donors are emerged in the alkaline catholyte and form hydrated clusters (AH)n(H2O)m of alkaline hydride. These particles as very strong reducers have a molar portion more than the gaseous hydrogen in the aqueous coolant and are the effective remedy for holding the negative Redox potential as an effect of hydrogen water chemistry in PWR. (authors)

  12. Water quality keeping system for reactor primary coolant circuit

    International Nuclear Information System (INIS)

    Sampled water at the exit of a condensate desalting tower taken out from a sampling pipe of an inline specimen sampling system is analyzed and evaluated by an organic impurity analyzer as to ions formed therein in a reactor pressure vessel. For example, when an aromatic sulfonic acid as main effluents from cation resins is present, it is converted to sulfuric acid then applied with quantitative analysis and electroconductivity measurement. These measured values are cross checked with calculation values from an equivalent ionic conductivity, further, a reactor water conductivity and a reactor water sulfuric acid concentration are forecast by introducing values such as of the reactor water flow rate, condensate flow rate, reactor water cleanup system flow rate and reactor water cleanup system removing rate. When the forecast value does not satisfy a standard reactor water quality control value, an exit valve is closed automatically by a system control/driving device and an inlet valve is opened, to isolate the condensate desalting tower. In such a system, presence of organic impurities can be forecast based on the water quality monitor of a condensate system before the organic impurities are charged into the reactor core to change the water quality of primary coolants. (I.S.)

  13. Field experience with advanced methods of on-line monitoring of water chemistry and corrosion degradation in nuclear power stations

    International Nuclear Information System (INIS)

    Advanced methods for on-line, in-situ water chemistry and corrosion monitoring in nuclear power stations have been developed during the past decade. The terms ''on-line'' and ''in-situ'' characterize approaches involving continuous measurement of relevant parameters in high temperature water, preferably directly in the systems and components and not in removed samples at room temperature. This paper describes the field experience to-date with such methods in terms of three examples: (1) On-line chemistry monitoring of the primary coolant during shutdown of a Type WWER-440 PWR. (2) Redox and corrosion potential measurements in final feedwater preheaters and steam generators of two large KWU PWRs over several cycles of plant operation. (3) Real-time, in-situ corrosion surveillance inside the calundia vault of a CANDU reactor. The way in which water chemistry sensors and corrosion monitoring sensors complement each other is outlined: on-line, in-situ measurement of pH, conductivity and redox potential gives information about the possible corrosivity of the environment. Electrochemical noise techniques display signals of corrosion activity under the actual environmental conditions. A common experience gained from separate use of these different types of sensors has been that new and additional information about plants and their actual process conditions is obtained. Moreover, they reveal the intimate relationship between the operational situation and its consequences for the quality of the working fluid and the corrosion behaviour of the plant materials. On this basis, the efficiency of the existing chemistry sampling and control system can be checked and corrosion degradation can be minimized. Furthermore, activity buildup in the primary circuit can be studied. Further significant advantages can be expected from an integration of these various types of sensors into a common water chemistry and corrosion surveillance system. For confirmation, a complete set of sensors

  14. Water chemistry control practices and data of the European BWR fleet

    International Nuclear Information System (INIS)

    Nineteen BWR plants are in operation in Europe, nine built by ASEA Atom, six by Siemens KWU and four by General Electric. This paper gives an overview of water chemistry operation practices and parameters of the European BWR plants. General design characteristics of the plants are described. Chemistry control strategies and underlying water chemistry guidelines are summarized. Chemistry data are presented and discussed with regard to plant design characteristics. The paper is based on a contract of the European BWR Forum with AREVA on a chemistry sourcebook for member plants. The survey of chemistry data was conducted for the years 2002 to 2008. (author)

  15. Tentative design basis new 100 Area water plant embodying a close cooling water circuit

    Energy Technology Data Exchange (ETDEWEB)

    1951-11-14

    The attached document includes a plot plan, flow diagram and delineation of basic assumptions upon which the report was developed. It summarizes the work which has been accomplished to date under RDA No. DC-6 in developing a recirculating water system to serve a new reactor. In order to proceed with the work under RDA No. DC-6 it has been necessary to make certain basic assumptions relative to the primary circuit requirements of RDA No. DC-3. These assumptions are explained in the report and are presented by the exhibits contained therein. Subsequent to the compilation of the basic report certain additional considerations have come to the authors attention and are included in the addendum.

  16. Influence of water chemistry on fuel cladding behaviour. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    For the purpose of the meeting water chemistry included the actual practice, the water chemistry monitoring and the on-going research. Corrosion included also hydriding, recent observations made in reactors, modelling and the recent research carried out. Fifty seven participants representing twenty countries attended the thirty formal presentations and the subsequent discussions. The thirty papers presented were split into five sessions covering, Reactor experience, Mechanism and Modelling, Oxidation and hydriding, On-line monitoring of water chemistry and the review of existing and advanced water chemistries. Four panel discussions including ''Corrosion mechanism and Modelling'', ''Corrosion and Hydriding'', ''Plant Experience and Loop Experiments'', Water Chemistry, Current Practice and Emerging Solutions'' and ''On-line Monitoring of Water Chemistry and Corrosion'' were organized. The main points of discussion focussed on the optimization of water chemistry, the compatibility of potassium water chemistry with the utilization of Zircaloy 4 or the utilization of zirconium niobium cladding with lithium water chemistry. The effect of the fabrication route and of the cladding composition (Sn content) on the corrosion kinetics, the state of the art and the correlative gaps in cladding corrosion modelling and the recent developments of on-line monitoring of water chemistry together with examination of suitable developments, were also discussed. Refs, figs, tabs

  17. Irradiation assisted stress corrosion cracking of stainless alloys in BWR normal water chemistry and hydrogen water chemistry

    International Nuclear Information System (INIS)

    Results are reported from a research project with the objectives to investigate the conditions for irradiation assisted stress corrosion cracking (IASCC), and to explore possible remedies. Constant extension rate tensile (CERT) tests were run on specimens of Type 304 stainless steel (SS), Type 316 SS and Alloy 800, which were irradiated in a commercial BWR to fast neutron fluences ranging from 3·1020 to 4·1021 n/cm2 (E>1 MeV). Some of the specimens were under tensile stress during irradiation. Tests were performed in a test loop using reactor water at a high flow rate. The tests were made with normal BWR water chemistry (NWC), BWR hydrogen water chemistry (HWC) and hydrogen peroxide dope NWC or HWC. In oxidizing environment (NWC or H2O2) doped environments Type 316 SS, and possibly Alloy 800, was much less susceptible to IASCC than the Type 304 SS materials. There was no susceptibility to IASCC below a fluence of 5·1020 n/cm2 (E>1 MeV). At approximately 1·1021 n/cm2 (E>1 MeV) a sharp increase in IASCC susceptibility for Type 304 SS was found. The effects of load during irradiation and flux at constant fluence were also investigated

  18. Comparison of French and German NPP water chemistry programs

    International Nuclear Information System (INIS)

    PWRs in the western hemisphere obey basically the same rules concerning design, choice of material and operational mode. In spite of these basic similarities, the manufacturers of PWRs in different countries developed different solutions in respect to single components in the steam/water cycle. Looking specifically at France and Germany, the difference in the tubing material of the steam generators (Inconel 600/690 chosen by Framatome and Incoloy 800 chosen by the former Siemens KWU) led to specific differences in the respective chemistry programs and in some respect to different 'philosophies' in operating the water/steam cycle. Compared to this, basic differences in operating the reactor coolant system cannot be observed. Nevertheless specific solutions as zinc injection and the use of enriched B-10 are applied in German PWRs. The application of such measures arises from a specific dose rate situation in older PWRs (zinc injection) or from economic reasons mainly (B-10). (authors)

  19. Modeling and management of pit lake water chemistry 1: Theory

    International Nuclear Information System (INIS)

    Highlights: • Review of pit lake literature in the context of pit lake predictions. • Review of approaches used to predict pit wall-rock runoff and leachate. • Review of approaches used to generate a pit lake water balance. • Review of approaches used to generate a hydrodynamic prediction. • Review of approaches used to generate a geochemical prediction of a future pit lake. - Abstract: Pit lakes are permanent hydrologic/landscape features that can result from open pit mining for metals, coal, uranium, diamonds, oil sands, and aggregates. Risks associated with pit lakes include local and regional impacts to water quality and related impacts to aquatic and terrestrial ecosystems. Stakeholders rely on predictive models of water chemistry to prepare for and manage these risks. This paper is the first of a two part series on the modeling and management of pit lakes. Herein, we review approaches that have been used to quantify wall-rock runoff geochemistry, wall-rock leachate geochemistry, pit lake water balance, pit lake limnology (i.e. extent of vertical mixing), and pit lake water quality, and conclude with guidance on the application of models within the mine life cycle. The purpose of this paper is to better prepare stakeholders, including future modelers, mine managers, consultants, permitting agencies, land management agencies, regulators, research scientists, academics, and other interested parties, for the challenges of predicting and managing future pit lakes in un-mined areas

  20. U.S. experience with hydrogen water chemistry in boiling water reactors

    International Nuclear Information System (INIS)

    Hydrogen water chemistry in boiling water reactors is currently being adopted by many utilities in the U.S., with eleven units having completed preimplementation test programs, four units operating permanently with hydrogen water chemistry, and six other units in the process of installing permanent equipment. Intergranular stress corrosion cracking protection is required for the recirculation piping system and other regions of the BWR systems. The present paper explores progress in predicting and monitoring hydrogen water chemistry response in these areas. Testing has shown that impurities can play an important role in hydrogen water chemistry. Evaluation of their effects are also performed. Both computer modeling and in plant measurements show that each plant will respond uniquely to feedwater hydrogen addition. Thus, each plant has its own unique hydrogen requirement for recirculation system protecion. Furthermore, the modeling, and plant measurements show that different regions of the BWR respond differently to hydrogen injection. Thus, to insure protection of components other than the recirculation systems may require more (or less) hydrogen demand than indicated by the recirculation system measurements. In addition, impurities such as copper can play a significant role in establishing hydrogen demand. (Nogami, K.)

  1. Experience in performing the commissioning procedures for meeting the requirements of water chemistry at NPP With VVER

    International Nuclear Information System (INIS)

    The integrity of NPP Unit equipment and pipelines is assured by strict following the requirements of rules and regulations by the NPP personnel in the field of nuclear power engineering and other regulatory documents. But all efforts of NPP personnel are unavailing in case of violation of the requirements of design documentation during Unit commissioning. Here the surface cleanness of equipment and pipelines during mounting, the post-mounting cleaning and assurance of water chemistry quality figures during commissioning procedures are of importance. During commissioning activities at the Unit of NPP with VVER a number of procedures are performed and the important place belongs to the procedures on water chemistry coordination. Post-mounting washing of steam generators is intended for cleaning and washing the steam generator internal surfaces against corrosion products, corrosive impurities, preservative residue and mounting fouling. During circulation washing of the reactor plant primary circuit the final cleaning of the internal surfaces is performed as well as preparing for formation of the protective oxide film. During reactor plant «hot» running-in the homogeneous solid protective oxide film is formed during a long-term interaction of the primary circuit internal surfaces with the alkaline reducing medium created due to proportioning of hydrazine and potassium hydroxide into the primary water. The composition and structure of the protective oxide film, formed on the internal surfaces, is such that its safe keeping is assured during Unit further operation. (author)

  2. Alternative water chemistry for the primary loop of PWR plants

    International Nuclear Information System (INIS)

    Advanced fuel element concepts (longer cycles, higher burnup, increased rod power) call for more reactivity binding capacity and, moreover, might produce higher void fractions, particularly in the hot channel. Thus, on the one hand, more alcalizing agent is needed to maintain a high coolant pH according to the approved ''modified boron-lithium mode of operation'' in the presence of more boric acid (chemical shim); on the other hand, increasing enrichment of coolant constituents due to local boiling (higher void fraction), which must not result in accelerated corrosion of fuel cladding and structural materials, imposes enhanced requirements on both, materials technology and water chemistry. At present, the use of boric acid enriched in B10 (the isotope effective in terms of reactivity control) appears to advantageously compromise in capturing more neutrons with less total boron while maintaining or even slightly reducing lithium concentrations at the same time. There is no feasible alternative for boric acid used as the chemical shim and for hydrogen gas as the reducing agent used to suppress oxygen formation by water radiolysis. Systematic screening as performed in phase 1 of a recent project proved potassium hydroxide to be the only potential candidate to favourably replace lithium 7 hydroxide as an alcalizing agent. Unfortunately, the results of pertinent comparative corrosion tests are not unambiguous, and available operational experience with potassium hydroxide in WWER plants is not readily applicable to western world-type PWR plants. Therefore, a switch-over from lithium to potassium can be envisaged only subsequent to a comprehensive qualification program which is planned to be the objective of phase 2 of the project. This program should also comprise zinc addition tests in order to confirm the alleged positive impact of this element on corrosion rates and activity buildup. Supplementary, it is recommended to consider amendments to existing water chemistry

  3. Present and future activities of the water chemistry research committees in JAES

    International Nuclear Information System (INIS)

    Research committee on water chemistry was established in 1982 in Japan Atomic Energy Society (JAES) and has continued its activities. Many internal and international activities of the water chemistry groups have been based on the Committee. The activity so far and the future prospect are described. As internal activities within the JAES, research committees and the resulting reports are enumerated. International activities, including supporting of the JAIF (Japan Atomic Industrial Forum) Conferences on Water Chemistry, are also mentioned. (Yamamoto, A.)

  4. Radiation Protection Aspects of Primary Water Chemistry and Source-term Management Report

    International Nuclear Information System (INIS)

    Since the beginning of the 1990's, occupational exposures in nuclear power plant has strongly decreased, outlining efforts achieved by worldwide nuclear operators in order to reach and maintain occupational exposure as low as reasonably achievable (ALARA) in accordance with international recommendations and national regulations. These efforts have focused on both technical and organisational aspects. According to many radiation protection experts, one of the key features to reach this goal is the management of the primary system water chemistry and the ability to avoid dissemination of radioactivity within the system. It outlines the importance for radiation protection staff to work closely with chemistry staff (as well as operation staff) and thus to have sufficient knowledge to understand the links between chemistry and the generation of radiation field. This report was prepared with the primary objective to provide such knowledge to 'non-chemist'. The publication primarily focuses on three topics dealing with water chemistry, source term management and remediation techniques. One key objective of the report is to provide current knowledge regarding these topics and to address clearly related radiation protection issues. In that mind, the report prepared by the EGWC was also reviewed by radiation protection experts. In order to address various designs, PWRs, VVERs, PHWRs and BWRs are addressed within the document. Additionally, available information addressing current operating units and lessons learnt is outlined with choices that have been made for the design of new plants. Chapter 3 of this report addresses current practices regarding primary chemistry management for different designs, 'how to limit activity in the primary circuit and to minimise contamination'. General information is provided regarding activation, corrosion and transport of activated materials in the primary circuit (background on radiation field generation). Primary chemistry aspects that

  5. Physical treatment of water from heater circuit by magnetic fields

    International Nuclear Information System (INIS)

    Magnetic scale control technologies can be used as a replacement for most water-softening equipment. Specifically, chemical softening, ion exchange and reverse osmosis, when used for control of hardness, could be replaced by magnetic water treatment technologies which use a magnetic field to alter the reaction between scale-forming ions in hard water. Hard water contains high levels of calcium, and other divalent cations. When subjected to heating, the divalent ions forms insoluble compounds with anions such as carbonate. These insoluble compounds have a much lower heat transfer capability than the metal. Because they are insulators, additional fuel consumption would be required to transfer on equivalent amount of energy. The general principle for the magnetic technology is a result of physical interaction between a magnetic field and a moving electric charge, in this case in the form of ions. When ions pass through the magnetic field, a force is exerted on each ion. The forces on ions of opposite charges are in opposite directions. The redirection of the particles tends to increase the frequency with which ions of opposite charge collide and combine to form a mineral precipitate, or insoluble compound. Since this reaction takes place in a low temperature region of a heat exchange system, the scale formed is non-adherent. The magnetic field can be realized with permanent magnets or electromagnets. There are two electromagnetic devices: invasive and non-invasive. Invasive devices have parts or the whole operating equipment within the flow field. This device requires the removal of a pipe section for insertion. Non-invasive devices are completely external to pipe, and thus can be installed while the pipe is in operation. We have under study a non-invasive electromagnetic device. In the paper it is largely presented. (authors)

  6. Physical treatment of water from heater circuit by magnetic fields

    International Nuclear Information System (INIS)

    Magnetic scale control technologies can be used as a replacement for most water-softening equipment. Specifically, chemical softening, ion exchange and reverse osmosis, when used for control of hardness, could be replaced by magnetic water treatment technologies which use a magnetic field to alter the reaction between scale-forming ions in hard water. Hard water contains high levels of calcium, and other divalent cations. When subjected to heating, the divalent ions forms insoluble compounds with anions such as carbonate. These insoluble compounds have a much lower heat transfer capability than metal. Because they are insulators, additional fuel consumption would be required to transfer on equivalent amount of energy. The general principle for the magnetic technology is a result of physical interaction between a magnetic field and a moving electric charge, in this case in the form of ions. When ions pass through the magnetic field, a force is exerted on each ion. The forces on ions of opposite charges are in opposite directions. The redirection of the particles tends to increase the frequency with which ions of opposite charge collide and combine to form a mineral precipitate, or insoluble compound. Since this reaction takes place in a low temperature region of a heat exchange system, the scale formed is non-adherent. The magnetic field can be realized with permanent magnets or electromagnets. There are two electromagnetic devices: invasive and non-invasive. Invasive devices have parts or the whole operating equipment within the flow field. This device requires the removal of a pipe section for insertion. Non-invasive devices are completely external to pipe, and thus can be installed while the pipe is in operation. We have under study a non-invasive electromagnetic device. In the paper it is largely presented. (authors)

  7. Introduction to Chemistry for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.

    Science.gov (United States)

    South Dakota Dept. of Environmental Protection, Pierre.

    Presented are basic concepts of chemistry necessary for operators who manage drinking water treatment plants and wastewater facilities. It includes discussions of chemical terms and concepts, laboratory procedures for basic analyses of interest to operators, and discussions of appropriate chemical calculations. Exercises are included and answer…

  8. BWR plant-to-fleet water chemistry trends -- Past and present

    International Nuclear Information System (INIS)

    Good water chemistry control is important for the integrity and satisfactory performance of BWRs. A historical review of selected chemistry performance indicators (e.g., conductivity) illustrates the improved chemistry control today relative to that in the past as well as the ability to evaluate these operational indicators

  9. Intelligent monitoring of water chemistry - Diagnostic expert system DIWATM

    International Nuclear Information System (INIS)

    For fast and comprehensive evaluation of power plant water chemistry conditions and reliable diagnosis in the event of disturbances considerable advantages are provided by employment of the Diagnostic Expert System DIWA. The interface to the process control system (I and C) and the integration of the DIWA system in the office PC network are the preconditions that DIWA operates as a monitoring system in real time. The performance of diagnosis, which are processed by a fuzzy-logic-supported knowledge base ensures not only the detection of all disturbances but also different analyses of the plant operation mode. By editing the knowledge base the Al of the system can increase without system programming. (authors)

  10. Electrochemical potential measurements under simulated BWR water chemistry conditions

    International Nuclear Information System (INIS)

    This paper discusses electrochemical potentials (ECP) measured in a high-temperature test loop under various water chemistry conditions. Several types of reference electrodes were used in this study. Effects of chemical additives were systematically examined, and the shift of ECP was found to be relatively small (±50 mV) by the addition of most common chemicals studied. However, the effects of Cu ions on the ECP of stainless steel and other materials are more significant. The effect of H2O2 was semi-quantitatively determined. The increase of ECP, compared with the dissolved O2 at similar levels was found to range from ∼200 mV to ∼500 mV. The effect is attributed to the oxidizing radicals produced from the catalytic decomposition of H2O2 on the stainless steel surface

  11. Impact of reactor water chemistry on cladding performance

    International Nuclear Information System (INIS)

    Water chemistry may have a major impact on fuel cladding performance in PWRs. If the saturation temperature on the surface of fuel cladding is exceeded, either because of the thermal hydraulics of the system, or because of crud deposition, then LiOH concentration can occur within thick porous oxide films on the cladding. This can degrade the protective film and accelerate the corrosion rate of the cladding. If sufficient boric acid is also present in the coolant then these effects may be mitigated. This is normally the case through most of any reactor fuel cycle. Extensive surface boiling may disrupt this equilibrium because of the volatility of boric acid in steam. Under such conditions severe cladding corrosion can ensue. The potential for such effects on high burnup cladding in CANDU reactors, where bone acid is not present in the primary coolant, is discussed. (author)

  12. Actual problems of vibroacoustic diagnostics of the first circuit of water-water energetic reactors

    International Nuclear Information System (INIS)

    The analysis of features of development of resonant oscillatory processes in the first circuit of WWER-1000 reactors is made. The settlement acoustic scheme for determination of own frequencies of oscillatory pressure of a two-phase stream is considered. Typical ranges of pulsations of pressure, and also data on nature of destructions of elements of the first circuit are presented

  13. Expert System for Diagnostics and Status Monitoring of NPP Water Chemistry Condition

    International Nuclear Information System (INIS)

    Water chemistry condition (WCC) has been the subject of constant study and improvement up to the present day. It is connected with the presence of a direct relationship between the violation of water chemistry regulation on the one hand and components reliability of the circuit's equipment and cost-effectiveness of their operation on the other. It dictates the necessity to apply different optimization methods in the field of monitoring and use of information - analytical and diagnostic systems to assess WCC quality, control and support. By now NPP experts have broad experience in revealing and removing the causes of WCC disturbances. However this knowledge is often of an intuitive, non-classified nature, scattered among various working documents, which makes their transfer difficult. Based on what has been mentioned above, special attention is currently being paid to the problem of creating expert diagnostic systems for supporting the optimum WCC. The existing developments in this field (DIWA, Smart chem Works, the water quality control system at the Onagava NPP etc. [1,3,4,5] are based on wide use of experts' knowledge. Such expert diagnostic systems for supporting WCC refer to the new generation of intellectual control methods, which allow the incorporation of the latest achievements both in the field of water chemistry simulation and in the field of artificial intelligence and computer technologies. LI 'VNIPIET' employees have, for several years, been developing an expert diagnostic system for supporting WCC and status monitoring of RBMK - reactor NPPs [2]. This system has not only conveniently organized the traditional functions of information acquisition and storage, a complete presentation of information in the form of tables, graphs of a dynamical changes of parameters and formation regular reports, diagnostic functions and issuing recommendations on WCC correction, but it also allows the assessment of confidence in the diagnosis made, relying on a wide

  14. Evaluation of the corrosion, reactivity and chemistry control aspects for the selection of an alternative coolant in the secondary circuit of sodium fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Brissonneau, L.; Simon, N. [CEA Cadarache, Nuclear Energy Division, DTN/STPA/LPC, 13 - Saint-Paul-lez-Durance (France); Balbaud-Celerier, F.; Courouau, J.L.; Martinelli, L. [CEA Saclay, Nuclear Energy Division, DPC/SCCME/LECNA, 91 - Gif-sur-Yvette (France); Grabon, V. [Areva NP, NEEL - FM (France); Capitaine, A. [EdF SEPTEN, 69 - Lyon (France); Conocar, O. [CEA Marcoule, Nuclear Energy Division, DRCP/GEAT/GEDM, 30 (France); Blat, M. [EdF R and D, 78 - Chatou (France)

    2009-07-01

    Full text of publication follows: Sodium Fast Reactors are promising fourth generation reactors as they can contribute to reduce resource demand in uranium and considerably reduce waste level due to their fast spectrum. However, progress can be obtained for these reactors on the investment cost and on safety improvement. To achieve these goals, one of the innovative solutions consists in eliminating the reaction of sodium with water in the steam generators, by replacing the sodium in the secondary circuit by another coolant. A work group composed of experts from CEA, Areva NP and EdF was in charge to evaluate several alternative coolants as Heavy Liquid Metals (HLM), nitrate salts and hydroxide mixtures, through a multi-criteria analysis. Three important criteria for the selection of one coolant are its 'Interactions with the structures', and its 'chemistry control', and 'Reactivity with fluids' which are strongly correlated. The assessment, mainly based on the state-of-art from published literature on these points, is detailed in this paper. The mechanisms of corrosion of steels by the HLM depend on the oxygen content. For Pb-Bi, it has been modelled for oxidation and release domains. The corrosion of steels by nitrate salts presents similarity with the oxidation induced by HLM. The highly corrosive hydroxide mixture requires the use of nickel base alloys, for which oxidation and mass transfer are nevertheless significant. The HLM requires a fine regulation of oxygen content, through measurements and control systems, both to prevent lead oxide precipitation at high level and release corrosion at low level. Nitrate salts decompose into nitrites at sufficiently high temperature, which might induce pressure build-up in the circuit. The hydroxides must be kept under reducing atmosphere to lower the corrosion rate. Though these coolants are relatively inert to air and water, one of the main drawbacks of HLM and nitrate salts are their

  15. Erosion-corrosion tests on ITER copper alloys in high temperature water circuit with incident heat flux

    International Nuclear Information System (INIS)

    To investigate the erosion-corrosion behavior of the Cu-alloys, i.e. CuCrZr and CuAl25-candidate materials for the manufacture of the diverter cooling channels for ITER, a test loop has been developed for testing erosion-corrosion behavior under high heat flux conditions. The heat loads on the test specimen surface amounts to 10 MW/m2. Under adverse testing conditions in oxidizing water (5-10 ppm H2O2) at 100 deg. C, with a flow velocity of 10 m/s and intermittent heat loading, followed by cooling cycles under oxidizing conditions maintained, CuCrZr alloy has shown the formation of a thick surface oxide films (essentially cupric oxide, CuO). This surface layer seems loosely adhesive, and detachable by mechanical or thermal shocks, or by fluid flow velocity effects. Indicated with a rough morphology, surface attacks were somewhat observed in areas after the surface oxide layer spalled off. Present results suggest the necessity for, such as, strict hydrogen water chemistry (HWC), in order to limit the copper corrosion rate or at least the release of copper into the cooling water circuit

  16. VGB conference 'Power plant chemistry 1997' - VGB feed water meeting. Proceedings

    International Nuclear Information System (INIS)

    The papers in this proceedings volume report on developments in power plant chemistry, addressing the following subject fields and activities: water treatment, water chemistry and anti-corrosion protection, demineralisation and other cleaning measures in steam generator units, flue gas desulfurization, nitrogen oxide removal from flue gas, liquid effluents treatment, and minimization of wastes. Papers from the session on power plant chemistry present recennt methods for lowering radioactivity levels in the primary cycles of PWRs and BWRs. (orig./CB)

  17. Photosynthetic water oxidation: insights from manganese model chemistry.

    Science.gov (United States)

    Young, Karin J; Brennan, Bradley J; Tagore, Ranitendranath; Brudvig, Gary W

    2015-03-17

    Catalysts for light-driven water oxidation are a critical component for development of solar fuels technology. The multielectron redox chemistry required for this process has been successfully deployed on a global scale in natural photosynthesis by green plants and cyanobacteria using photosystem II (PSII). PSII employs a conserved, cuboidal Mn4CaOX cluster called the O2-evolving complex (OEC) that offers inspiration for artificial O2-evolution catalysts. In this Account, we describe our work on manganese model chemistry relevant to PSII, particularly the functional model [Mn(III/IV)2(terpy)2(μ-O)2(OH2)2](NO3)3 complex (terpy = 2,2';6',2″-terpyridine), a mixed-valent di-μ-oxo Mn dimer with two terminal aqua ligands. In the presence of oxo-donor oxidants such as HSO5(-), this complex evolves O2 by two pathways, one of which incorporates solvent water in an O-O bond-forming reaction. Deactivation pathways of this catalyst include comproportionation to form an inactive Mn(IV)Mn(IV) dimer and also degradation to MnO2, a consequence of ligand loss when the oxidation state of the complex is reduced to labile Mn(II) upon release of O2. The catalyst's versatility has been shown by its continued catalytic activity after direct binding to the semiconductor titanium dioxide. In addition, after binding to the surface of TiO2 via a chromophoric linker, the catalyst can be oxidized by a photoinduced electron-transfer mechanism, mimicking the natural PSII process. Model oxomanganese complexes have also aided in interpreting biophysical and computational studies on PSII. In particular, the μ-oxo exchange rates of the Mn-terpy dimer have been instrumental in establishing that the time scale for μ-oxo exchange of high-valent oxomanganese complexes with terminal water ligands is slower than O2 evolution in the natural photosynthetic system. Furthermore, computational studies on the Mn-terpy dimer and the OEC point to similar Mn(IV)-oxyl intermediates in the O-O bond

  18. Water chemistry of PHT system during hot conditioning of KAPP-2

    International Nuclear Information System (INIS)

    The formation of magnetite on the carbon steel surfaces of the primary heat transport (PHT) system depends primarily on the maintenance of good water chemistry of the system during hot conditioning. This paper describes experiences of maintaining water chemistry during the hot conditioning of Kakrapar Atomic Power Project 2 (KAPP-2). (author). 4 refs., 1 fig

  19. Pore water chemistry in the beach sands of central Tamil Nadu, India

    Digital Repository Service at National Institute of Oceanography (India)

    Chandrasekar, N.; Gujar, A.R.; Loveson, V.J.; Rajamanickam, G.V.; Moscow, S.; Manickaraj, D.S.; Chandrasekaran, R.; Chaturvedi, S.K.; Mahesh, R.; Sudha, V.; Josephine, P.J.; Deepa, V.

    As the pore water chemistry- has been considered as one of the prominent base parameters to infer the impact of coastal mining in introducing environmental deterioration, a study in pore water chemistry is planned here along the beaches for a length...

  20. History of the water chemistry for the few tube test model

    International Nuclear Information System (INIS)

    The water chemistry activities carried out in support of the Few Tube Test are described. This test was conducted to provide design confirmation data for the Clinch River Breeder Reactor Project (CRBRP) steam generators. Proposed CRBRP chemistry was followed; all volatile treatment (AVT) of water was carried out with on-line monitoring capability

  1. Update of the water chemistry effect on the flow-accelerated corrosion rate of carbon steel: influence of hydrazine, boric acid, ammonia, morpholine and ethanolamine

    International Nuclear Information System (INIS)

    The influence of the water chemistry on Flow-Accelerated Corrosion (FAC) affecting carbon steel components has been studied for many years and is relatively well known and taken into account by the models. Nonetheless, experimental studies were conducted in the last few years at EDF on the CIROCO loop in order to check the influence of the water chemistry parameters (hydrazine, boric acid, ammonia, morpholine and ethanolamine) on the FAC rate of carbon steel in one phase flow conditions. The hydrazine impact on the FAC rate was shown to be minor in EDF's chemistry recommendation range, compared to other parameters' effects such as the pH effect. The presence of boric acid in the nominal secondary circuit conditions was negligible. Finally, as expected, the nature of the chemical conditioning (ammonia, morpholine or ethanolamine) did not modify the FAC rate, the influencing chemical variable being the at-temperature pH in one-phase flow conditions. (author)

  2. Linking soil- and stream-water chemistry based on a Riparian Flow-Concentration Integration Model

    OpenAIRE

    J. Seibert; T. Grabs; Köhler, S; H. Laudon; Winterdahl, M.; Bishop, K.

    2009-01-01

    The riparian zone, the last few metres of soil through which water flows before entering a gaining stream, has been identified as a first order control on key aspects of stream water chemistry dynamics. We propose that the distribution of lateral flow of water across the vertical profile of soil water chemistry in the riparian zone provides a conceptual explanation of how this control functions in catchments where matrix flow predominates. This paper presents a mathematical implementation of ...

  3. Steam generator local water chemistry and SCC of austenitic steel

    International Nuclear Information System (INIS)

    The titanium stabilized austenitic steel similar to the type of 321 is sensitive to the stress corrosion cracking under horizontal steam generator operating condition. SCC was observed under crevice corrosion parameters and has resulted in the transgranular or intergranular cracking at the both, components primary collectors and heat exchange tubes. The crevice environment is characterized by aggressive impurities and 'non aggressive' compounds. Sulfates and chlorides as aggressive species and silicates and alumino-silicates as 'non aggressive' species on the other hand are present in significant amount in the crevice environment under operating condition. Local water chemistry parameters were evaluated with MULTEQ Code. As input data the measured operational values of local and bulk environments have been used. The determined parameters were compared with the results of thread hole environment analyses and tube surface investigations respectively. Results of the hideout return profiles measurement showed an increase of sulfate concentration by one order of magnitude. Increase of the chloride content was not been observed, its value remains at operation levels. Examination of surface layers showed the preferential accumulation of sulfates, silicates and alumino-silicates in the deposit at tube support plates and in thread holes comparing relative to free span surfaces. The content of species in the water and deposits and the crystallographic structure of deposits correspond to MULTEQ results. Rising displacement tests were carried out with 0.5T CT specimens at a temperature 275 degrees C in the model water environment which simulated the crevice conditions. The experimental values are presented for crack growth rate versus stress intensity factor. Corrosion damage of the titanium stabilized austenitic steel is likely to be determined by the presence of sulfates and chlorides and other aggressive agents, as Cu. It is supposed that other decisive factor is the

  4. PWR water chemistry controls: a perspective on industry initiatives and trends relative to operating experience and the EPRI PWR water chemistry guidelines

    International Nuclear Information System (INIS)

    An effective PWR water chemistry control program must address the following goals: Minimize materials degradation (e.g., PWSCC, corrosion of fuel, corrosion damage of steam generator (SG) tubes); Maintain fuel integrity and good performance; Minimize corrosion product transport (e.g., transport and deposition on the fuel, transport into the SGs where it can foul tube surfaces and create crevice environments for the concentration of corrosive impurities); Minimize dose rates. Water chemistry control must be optimized to provide overall improvement considering the sometimes variant constraints of the goals listed above. New technologies are developed for continued mitigation of materials degradation, continued fuel integrity and good performance, continued reduction of corrosion product transport, and continued minimization of plant dose rates. The EPRI chemistry program, in coordination with other EPRI programs, strives to improve these areas through application of chemistry initiatives, focusing on these goals. This paper highlights the major initiatives and issues with respect to PWR primary and secondary system chemistry and outlines the recent, on-going, and proposed work to effectively address them. These initiatives are presented in light of recent operating experience, as derived from EPRI's PWR chemistry monitoring and assessment program, and EPRI's water chemistry guidelines. (author)

  5. Magnetite reactivity in representative conditions of the secondary circuit of pressurized water reactors

    International Nuclear Information System (INIS)

    In the secondary circuit of Pressurized Water Reactors (PWR), magnetite deposits lead to steam generators (SG) fouling, which decreases thermal performances and enhances stress corrosion cracking (SCC). The aim of this study is to improve the understanding of magnetite particles behaviour and their reactivity in the secondary circuit conditions. Experimental tests investigated the fast thermal decomposition of hydrazine, injected in the secondary circuit to eliminate oxygen. Temperature, pH, and catalytic properties of materials surfaces have an influence on the kinetics of hydrazine decomposition. A predictive model was proposed. Growing, transport and deposits of iron oxides, essentially formed with magnetite, responsible of the steam generator fouling, were studied in the experimental loop FORTRAND, Formation and Transport of Deposits. Surface characterizations show that magnetite is the corrosion product formed on carbon steel and stainless steel at 220 C, and goethite is formed at room temperature on stainless steel. Results indicate also that the effect of different amines, used in the secondary circuit, on the soluble iron is principally due to their effect on the pH. Performed tests highlight transport and deposition of magnetite particles in the loop. Deposits formed in the SG could promote SCC of tubes by sorption and reduction of sulfates. To reproduce secondary circuit conditions, studies of sorption were made in reducing medium imposed by hydrazine. At 275 C, the presence of hydrazine has an effect on the speciation of sulfates in solution but does not seem to influence the sorption nor to lead to H2S(g) emission predicted by thermodynamic calculations. These experimental results are used to predict sulfur and iron species behaviour in the secondary circuit. Low pH conditioning enhances soluble iron concentration, consequently iron transport in the SG. Sulfides are the most probable sulfur species in flow-restricted areas of SG, harmful for stress

  6. Assessment of EPRI water chemistry guidelines for new nuclear power plants

    International Nuclear Information System (INIS)

    Water chemistry control technologies for nuclear power plants have been significantly enhanced over the past few decades to improve material and equipment reliability and fuel performance, and to minimize radionuclide production and transport. Chemistry Guidelines have been developed by the Electric Power Research Institute (EPRI) for currently operating plants and have been intermittently revised over the past twenty-five years for the protection of systems and components and for radiation management. As new plants are being designed for improved safety and increased power production, it is important to ensure that the designs consider implementation of state-of-the-art, industry developed water chemistry controls. In parallel, the industry will need to consider and update water chemistry guidelines as well as plant startup and operational strategies based on the advanced plant designs. EPRI has performed assessments of water chemistry control guidance or assumptions provided in design and licensing documents for several advanced plant designs. These designs include: Westinghouse AP1000 Pressurized Water Reactor AREVA US-EPR Pressurized Water Reactor Mitsubishi Nuclear Energy Systems/Mitsubishi Heavy Industries Advanced Pressurized Water Reactor Korea Hydro and Nuclear Power APR1400 Pressurized Water Reactor Toshiba Advanced Boiling Water Reactor (ABWR) General Electric-Hitachi Economic Simplified Boiling Water Reactor (ESBWR) The intent of these assessments was to identify key design differences in each of the new plant designs relative to the current operating fleet and to identify differences in water chemistry specifications or design assumptions provided in design and licensing documents for the plants in comparison to current EPRI Water Chemistry Guidelines. This paper provides a summary of the key results of these assessments. The fundamental design and operation of the advanced plants is similar to the currently operating fleet. As such, the new plants are

  7. Handbook of green chemistry, green solvents, reactions in water

    CERN Document Server

    Anastas, Paul T

    2014-01-01

    There has been dramatic growth in the community of researchers and industrialists working in the area of Green Chemistry. There has been an increasing recognition by a wide-range of scientists and engineers in the chemical enterprise that the framework of Green Chemistry is relevant and enabling to their work. There has been a significant body of work that has accumulated over the past decade that details the breakthroughs, innovation and creativity within Green Chemistry and Engineering. While there have been edited volumes on Green Chemistry that collect a limited number of papers often o

  8. Influence of Operating and Water-Chemistry Parameters on Fuel Cladding Corrosion and Steel Corrosion Products Deposition on Cladding Surfaces (2nd RCM Abstract)

    International Nuclear Information System (INIS)

    The deposits of crud is to be proportional to the amount of corrosion products circulating in the circuit, therefore all models of mass transfer in the circuit include the change of corrosion products concentration and the corrosion rate in time, removing these products by filters and deposition. During decontamination of the circuit segments and equipment replacement local change of corrosion rate occurs which results in the increase of corrosion products concentration in the circuit and the increase of deposits on surfaces. If due to incorrect water chemistry conditions for corrosion products deposition in the core are created not only the activity of the coolant increases but the hydraulic resistance of the reactor also grows which results in the increase of the pressure drop at the reactor. The problem was studied on the example of WWER-440 units. The influence was established not only of water-chemistry parameters, but also of units characteristics such as pressure drop at the beginning of cycle, number of decontaminations, the age of fuel assemblies (FA) and their alignment. The mathematical model of rate rise of pressure drop through reactor (PDR) during cycle was made. (author)

  9. Operational experience, evolution and developments in water chemistry in Indian Nuclear Power Plants - an overview

    International Nuclear Information System (INIS)

    Lessons learnt from the experiences at nuclear power plants have enriched the understanding of corrosion behaviour in water systems. The need for proper water chemistry control not only during operation but also during fabrication and preoperational tests is clearly seen. It should not be construed that maintenance of proper water chemistry is a panacea for all corrosion and other associated problems. Unless adequate care is taken in selection of material and sound design and fabrication practices are followed, no regime of water chemistry can help in eliminating failure due to corrosion

  10. Applications of the radiation chemistry of water: acid rain and nuclear power

    International Nuclear Information System (INIS)

    The radiation chemistry of water is sufficiently well known under ambient conditions that it is widely used to study the chemistry of free radicals in aqueous solution. One topical application described here is the hydroxyl radical-driven oxidation of sulphur dioxide to sulphuric acid in cloudwater to form acid rain. Another area of current interest is the effects of radiation on the cooling water of pressurized water reactors at ca. 3000C. In studying these effects new information is also being gained on the fundamental processes in the radiation chemistry of water and on the kinetics of fast reactions. (author)

  11. Water chemistry and microbial corrosion in oilfield water handling facilities: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jack, T.; Bramhill, B.

    1992-01-01

    This study was carried out in an oilfield waterflood operation in which produced brine is reinjected to displace more oil from the reservoir. Significant corrosion problems are associated with bacterial colonization of the water handling system. This report describes results of an audit of chemical, biological and corrosion parameters measured across the Wainwright waterflood operation over 30 months. Based on the insights obtained and previous observation of shifts in microbial populations with variations in water chemistry, a series of runs was conducted in the field test facility at unit 13 waterplant to investigate the effect of specific chemical additions.

  12. Effect of water chemistry on deposition for PWR plant operation

    International Nuclear Information System (INIS)

    For Pressurized Water Reactor (PWR) operation, water chemistry guidelines, specifications and associated surveillance programs are key to avoid deposition of oxides. Deposition of oxides can be detrimental by disrupting results of flow measurements, decreasing the thermal exchange capacity, or even by impairing safety. This paper describes the most important cases of deposition, their consequences for operation, and the implemented improvements to avoid their reoccurrence. Deposition that led to a Crud Induced Power Shift (CIPS) is also described. In the primary and in the secondary sides, orifice plates are typically used for measuring feedwater flow rate in nuclear power plants. Feedwater flow rates are used for control purposes and are important safety parameters as they are used to determine the plant's operating power level. Fouling of orifice plates in the primary side has been found during surveillance testing. For reactor coolant pumps, the formation of deposits on the seal No.1 can cause abnormally high or low leak rates through the seal. The leak rate through this seal must be carefully maintained within a prescribed range during plant operation. In the secondary side, orifice plate fouling has been the cause of feedwater flow/reference thermal power drift. For the steam generators (SG), magnetite deposition has led to fouling of the tube bundle, clogging of the quadri-foiled support plate holes and hard sludge formation on the base plate. For the generators, copper hollow conductors are widely used. Buildup of copper oxides on the interior walls of copper conductors has caused insufficient heat transfer. All these deposition cases have received adequate attention, understanding and response via improvement of our surveillance programs. (authors)

  13. Influence of operating and water-chemistry parameters on fuel cladding corrosion and deposition of corrosion products on cladding surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kritsky, V.G.; Berezina, I.G.; Rodionov, Y.A., E-mail: kritsky@givnipiet.spb.ru, E-mail: alemaskina@givnipiet.ru [Leading Inst. ' VNIPIET' , Saint Petersburg (Russian Federation)

    2010-07-01

    A description of mass transfer mechanism of corrosion products in the primary coolant circuit is a complicated problem. The deposits of crud is to be proportional to the amount of corrosion products circulating in the primary coolant circuit, therefore all models of mass transfer in the circuit include the change of corrosion products concentration and the corrosion rate in time, removing these products by filters and deposition. Decontamination of the circuit equipment and replacement work needs lead to a local change of corrosion rate which results in the increase of corrosion products concentration in the circuit and the increase of deposits on surfaces. If due to incorrect water chemistry conditions for corrosion products deposition in the core are created not only the activity of the coolant increases but the hydraulic resistance of the reactor also grows which results in the increase of the pressure drop at the reactor. The phenomenon of 'pressure drop' which takes place in NPP with VVER reactors was considered. The reasons of this phenomenon are the following: the great removal of corrosion products (CP) from steam generator surfaces after decontamination, change of CP behavior and then consequent deposit of CP on the fuel element surfaces; and, sub-cooled boiling takes place on the some of fuel element and results in the acceleration of corrosion products deposit, the increase of nuclide activation period and coolant radioactivity. A model was developed to explain pressure drop rise in-core and deposits redistribution in the core and in the primary circuit of NPP with VVER-440. The physical-chemical basis of the model is the transport corrosion products dependence on temperature, pH{sub T} value of coolant, and correlation between rates of corrosion products (Fe) formation (after steam generators decontamination) and their removing from the circuit. The aim of our modeling is to predict the growth of pressure difference on the basis of regular

  14. TRANP - a computer code for digital simulation of steady - state and transient behavior of a pressurizer water reactor primary circuit

    International Nuclear Information System (INIS)

    A digital computer code TRANP was developed to simulate the steady-state and transient behavior of a pressurizer water reactor primary circuit. The development of this code was based on the combining of three codes already developed for the simulation of a PWR core, a pressurizer, a steam generator and a main coolant pump, representing the primary circuit components. (Author)

  15. Chemistry

    International Nuclear Information System (INIS)

    The chemical research and development efforts related to the design and ultimate operation of molten-salt breeder reactor systems are concentrated on fuel- and coolant-salt chemistry, including the development of analytical methods for use in these systems. The chemistry of tellurium in fuel salt is being studied to help elucidate the role of this element in the intergranular cracking of Hastelloy N. Studies were continued of the effect of oxygen-containing species on the equilibrium between dissolved UF3 and dissolved UF4, and, in some cases, between the dissolved uranium fluorides and graphite, and the UC2. Several aspects of coolant-salt chemistry are under investigation. Hydroxy and oxy compounds that could be formed in molten NaBF4 are being synthesized and characterized. Studies of the chemistry of chromium (III) compounds in fluoroborate melts were continued as part of a systematic investigation of the corrosion of structural alloys by coolant salt. An in-line voltammetric method for determining U4+/U3+ ratios in fuel salt was tested in a forced-convection loop over a six-month period. (LK)

  16. Analysis of water hammer phenomena in RBMK-1500 reactor main circulation circuit

    International Nuclear Information System (INIS)

    Water hammer can occur in any thermal-hydraulic systems. Water hammer can reach pressure levels far exceeding the pressure range of a pipe given by the manufacturer, and it can lead to the failure of the pipeline integrity. In the past three decades, since a large number of water hammer events occurred in the light-water- reactor power plants, a number of comprehensive studies on the phenomena associated with water hammer events have been performed. There are three basic types of severe water hammer occurring at power plants that can result in significant plant damage: rapid valve operation events; void-induced water hammer; condensation-induced water hammer. Correct prediction of water hammer transients, is therefore of paramount importance for the safe operation of the plant. Therefore verifying of computer codes capability to simulate water hammer type transients is very important issue at performing of safety analyses for nuclear power plants. Verification of RELAP5/MOD3.3 code capability to simulate water hammer type transients employing the experimental investigations is presented. Experience gained from benchmarking analyses has been used at development of the detail RELAP5 code RBMK-1500 model for simulation of water hammer effects in reactor main circulation circuit. Analysis of reactor cooling system shows, that water hammers can occur in main circulation circuit of RBMK-1500 reactor in cases of: (1) Guillotine break of the inlet piping upstream of the Group Distribution Header and (2) Guillotine break of the pressure piping upstream the Main Circulation Pump check valve. Analysis of above mentioned accident scenarios is presented in this paper. First scenario of the accident potentially is more dangerous, because the pressure pulses influence not only the reactor cooling circuit, but also the piping of safety related system (Emergency Core Cooling System pipeline) connected to affected Group Distribution Header. The performed analysis using RELAP5 code

  17. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore Supra

    International Nuclear Information System (INIS)

    Full text of publication follows: Tore supra (TS) has used from the beginning of operation in 1989 actively cooled plasma facing components. Since the operation and baking temperature of all in vessel components has been defined to be up to 230 deg. C at 40 bars, a special water chemistry of the cooling water plant was suggested in order to avoid eventual water leaks due to corrosion (general corrosion, galvanic corrosion, stress corrosion, etc.) at relative high temperatures and pressures in tubes, pipes, bellows, water boxes, coils, etc. From the beginning of TS operation, in vessel components (e.g. wall protection panels, limiters, ergodic divertor coils, neutralisers and diagnostics) represented a unique combination of metals in the hydraulic circuit mainly such as stainless steel, Inconel, CuCrZr, Nickel and Copper. These different materials were joined together by welding (St to St, Inconel to Inconel, CuCrZr to CuCrZr and CuCrZr to St-St via a Ni sleeve adapter), brazing (St-St to Cu and Cu-LSTP), friction (CuCrZr and Cu to St-St), explosion (CuCrZr to St-St) and memory metal junction (Cryo-fit to Cu - only test sample). Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralized water with adjustment of the pH value to about 9.0/ 7.0 (25 deg. C/ 200 deg. C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 deg. C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal

  18. Effect of water chemistry on the oxide film on Alloy 690 during simulated hot functional testing of a pressurised water reactor

    International Nuclear Information System (INIS)

    Highlights: ► Influence of hot functional test chemistry on Alloy 690 oxidation studied by EIS/XPS. ► Increase in LiOH concentration leads to a higher dissolution rate of the oxide. ► Higher boric acid content leads to more efficient passivation of the surface. ► Oxidation parameters estimated by comparison of results to the Mixed-Conduction Model. - Abstract: Electrochemical impedance spectroscopic measurements to follow the oxidation of Alloy 690 in high-temperature water environments simulating hot functional test (HFT) chemistries are presented and discussed. The thickness and in-depth composition of the formed oxides is estimated by X-ray photoelectron spectroscopy. Kinetic and transport parameters of the oxidation process are estimated by quantitative comparison of the results with the mixed-conduction model for oxide films. Based on the influence of LiOH and H3BO3 concentrations on the parameter values, conclusions for the relationship between HFT water chemistry and the electrical and electrochemical properties of the passive layer on reactor coolant circuit surfaces are drawn.

  19. Characterisation of the inorganic chemistry of surface waters in South Africa

    OpenAIRE

    Huizenga, Jan Marten

    2011-01-01

    The main purpose of this study was to determine a simple inorganic chemistry index that can be used for all surface waters in South Africa, in order to characterise the inorganic chemistry of surface waters. Water quality data collected up until 1999 from all sample monitoring stations (2 068 monitoring stations, 364 659 samples) in South Africa were transformed into an Excel dataset and subsequently quality screened using the stoichiometric charge balance, after which 196 570 (41%) of the wa...

  20. Hydrogen water chemistry: can it work in a supercritical water reactor?

    International Nuclear Information System (INIS)

    Hydrogen water chemistry-the addition of a small amount of H2 to the reactor cooling water-is a spectacularly successful strategy for controlling water radiolysis and maintaining a corrosion potential low enough to inhibit stress corrosion cracking of primary cooling loop structural materials. It has become very clear from kinetic modeling with recently measured reaction rates, that the key reaction equilibrium is H2 + OH <==> H + H2O. A very small excess of H2 converts the oxidizing OH radical to reducing H atom, preventing formation of H2O2 and O2. The minimum amount of H2 which can prevent net radiolysis of water is referred to as the critical hydrogen concentration (CHC). As supercritical water is considered as the fluid of the primary cooling loops in advanced reactor designs, it is an obvious question to ask whether hydrogen water chemistry can work at the higher temperatures and large range of densities expected in such a reactor. To answer this simple question, we undertook experiments to measure the CHC in a small-scale flow experiment, using a 3MeV van de Graaff accelerator as the source of radiation. Surprising results were obtained. At 300oC, we could indeed suppress radiolysis in the water, but at supercritical temperatures, it seems that the addition of H2 actually stimulates further production of hydrogen. The talk will explore these results, examine the mechanism of corrosion of steel by H2O2, and consider the equilibrium H2 + OH <==> H + H2O in supercritical water.

  1. Ecology of Legionella within water cooling circuits of nuclear power plants along the French Loire River

    International Nuclear Information System (INIS)

    The cooling circuits of nuclear power plants, by their mode of operating, can select thermophilic microorganisms including the pathogenic organism Legionella pneumophila. To control the development of this genus, a disinfection treatment of water cooling systems with monochloramine can be used. To participate in the management of health and environmental risks associated with the physico-chemical and microbiological modification of water collected from the river, EDF is committed to a process of increasing knowledge about the ecology of Legionella in cooling circuits and its links with its environment (physical, chemical and microbiological) supporting or not their proliferation. Thus, diversity and dynamics of culturable Legionella pneumophila were determined in the four nuclear power plants along the Loire for a year and their links with physico-chemical and microbiological parameters were studied. This study revealed a high diversity of Legionella pneumophila subpopulations and their dynamic seems to be related to the evolution of a small number of subpopulations. Legionella subpopulations seem to maintain strain-specific relationships with biotic parameters and present different sensitivities to physico-chemical variations. The design of cooling circuits could impact the Legionella community. The use of monochloramine severely disrupts the ecosystem but does not select biocide tolerant subpopulations. (author)

  2. Operating experience in correcting severe secondary chemistry upsets by controlling makeup water organics (TOC)

    International Nuclear Information System (INIS)

    In this paper following observations are presented: conductivity and chloride excursions in steam condensate were directly linked to makeup water quality. Data strongly suggests that the breakdown of makeup water organics was responsible for substandard condensate water quality; although the short-term effects of gross organic contamination have been documented, the longer term consequences of continuous exposure by moderate organic levels needs to be addressed; a greater understanding of the organic removal efficiency of the various water purification technologies is essential to controlling TOC contamination; and a much better understanding of makeup plant chemistry and the interrelationship of makeup water contamination and plant chemistry has proven essential to optimizing plant performance and guaranteeing the best possible steam chemistry. The role of the chemistry group as an active participant in operations has been proven at Kewaunee Nuclear Plant

  3. Evolution of the water chemistry of Lake Orta after liming

    Directory of Open Access Journals (Sweden)

    Gabriele A. TARTARI

    2001-02-01

    Full Text Available Since 1963 Lake Orta has been an emblematic case of industrial pollution by heavy metals and acidifying compounds (ammonium sulphate, to the extent that up to 1989 it was the largest acidified deep lake in the world. The low pH values of between 3.9 and 4.4 helped to keep high the levels of toxic compounds in solution, such as copper, aluminium, zinc and nickel. The liming performed in 1989-1990 brought the pH back to neutral values, determining the precipitation of the metals and the recovery of normal chemical conditions. The main results of researches conducted continuously on the lake water chemistry from 1988 to March 2000 are as follows. The whole water mass has been completely neutralised since the beginning of 1991; pH subsequently rose until in 1999-2000 it reached the values (6.7-6.9 units of the years when the lake was in a natural condition. The alkaline reserve showed a continuous increase after the lake water was neutralised, until March 2000, when total alkalinity values levelled off at 0.19 meq l-1. The increase in pH has allowed a full recovery of nitrification processes; in fact, during the liming period the concentration of ammonium was drastically reduced, by over 80%; ammonium has been practically absent since the end of 1992, and it may be affirmed that the primary cause of the acidification of the lake has been completely removed. The nitrate content in the lake has almost halved compared with the mean concentrations measured before the liming; in March 2000 mean values of 2.0 mg N l-1 were measured, and it is likely that these values will fall further in the next few years, to below 1.5 mg N l-1. The concentrations of toxic metals have shown a progressive reduction, to the extent that in 1999 the content of copper and aluminium was close to zero in the whole water mass. The situation of Lake Orta has therefore improved enormously, and is now very similar to the original condition of the lake before it was polluted

  4. Chemical aspects of fission product transport in the primary circuit of a light water reactor

    International Nuclear Information System (INIS)

    The transport and fission products in the primary circuit of a light water reactor are of fundamental importance in assessing the consequences of severe accidents. Recent experimental studies have concentrated upon the behaviour of simulant fission product species such as caesium iodide, caesium hydroxide and tellurium, in terms of their vapour deposition characteristics onto metals representative of primary circuit materials. An induction furnace has been used to generate high-density/structural materials aerosols for subsequent analysis, and similar equipment has been incorporated into a glove-box to study lightly-irradiated UO/sub 2/ clad in Zircaloy. Analytical techniques are being developed to assist in the identification of fission product chemical species released from the fuel at temperatures from 1000 to 25000C. Matrix isolation-infrared spectroscopy has been used to identify species in the vapour phase, and specific data using this technique are reported

  5. Parameter Identification for a New Circuit Model Aimed to Predict Body Water Volume

    Directory of Open Access Journals (Sweden)

    GHEORGHE, A.-G.

    2012-11-01

    Full Text Available Intracellular and extracellular water volumes in the human body have been computed using a sequence of models starting with a linear first order RC circuit (Cole model and finishing with the De Lorenzo model. This last model employs a fractional order impedance whose parameters are identified using the frequency characteristics of the impedance module and phase, the latter being not unique. While the Cole model has a two octaves frequency validity range, the De Lorenzo model can be used for three decades. A new linear RC model, valid for a three decades frequency range, is proposed. This circuit can be viewed as an extension of the Cole model for a larger frequency interval, unlike similar models proposed by the same authors.

  6. Thermal-hydraulics analyses and external circuits layout for the EU DEMO water-cooled Pb-17Li blanket concept

    International Nuclear Information System (INIS)

    This paper describes the detailed thermal-hydraulics analyses performed on the EU reference design for DEMO water-cooled Pb-17Li blanket. It includes the calculation of pressure drops and flow-rates in the main fluid circuits (first-wall and Pb-17Li-pool water-cooling circuits and Pb-17Li circuit, for both inboard and outboard segments), and an Out-of-Vessel Loss-Of-Coolant Accident (LOCA) analysis showing that a LOCA in one of the two independent cooling-circuits does not lead to unacceptable temperatures in all parts of the blanket. A preliminary description of the external circuits layout (out-of-vessel) is also given in the paper. (orig.)

  7. Thermal-hydraulics analyses and external circuits layout for the EU DEMO water cooled Pb-17Li blanket concept

    International Nuclear Information System (INIS)

    This paper describes the detailed thermal-hydraulics analyses performed on the EU reference design for DEMO water-cooled Pb-17Li blanket. It includes the calculation of pressure drops and flow-rates in the main fluid circuits (first-wall and Pb-17Li-pool water-cooling circuits and Pb-17Li circuit, for both inboard and outboard segments), and an Out-of-Vessel Loss-Of-Coolant Accident (LOCA) analysis showing that a LOCA in one of the two independent cooling-circuits does not lead to unacceptable temperatures in all parts of the blanket. A preliminary description of the external circuits layout (out-of-vessel) is also given in the paper. (author) 6 refs.; 2 figs.; 5 tabs

  8. Present status and recent improvements of water chemistry at Russian VVER plants

    International Nuclear Information System (INIS)

    Water chemistry is an important contributor to reliable plant operation, safety barrier integrity, plant component lifetime, radiation safety, environmental impact. Primary and secondary water chemistry guidelines of Russian VVER plants have been modified to meet the new safety standards. At present 14 VVER units of different generation are in operation at 5 Russian NPPs. There are eight 4-loop pressurised water reactors VVER-1000 (1000 MWe) and six 6-loop pressurised water reactors VVER-440 (440 MWe). Generally, water chemistry at East European VVER plants (about 40 VVER-440 and VVER-1000 units in Ukraine, Bulgaria, Slovakia, Czech Republic, Hungary, Finland and Armenia) is similar to water chemistry at Russian VVER plants. Due to similar design and structural materials some water chemistry improvements were introduced at East European plants after they has been successfully implemented at Russian plants and vice versa. Some water chemistry improvements will be implemented at modern VVER plants under construction in Ukraine, Slovakia, Czech Republic, Iran, China, India. (R.P.)

  9. Water chemistry improvements in an operating boiling water reactor (BWR) and associated benefits

    International Nuclear Information System (INIS)

    Kernkraft Muhleberg (KKM) nuclear power plant is a BWR/4, the older of the two BWRs in Switzerland located in the outskirts of Bern. The plant is currently in its 37th year of continuous power operation, and has implemented major water chemistry improvements, including, hydrogen water chemistry (HWC), depleted zinc oxide (DZO) addition, NobleChem™, and On-Line NobleChem™ applications. In addition, the KKM plant has also performed other improvements such as maintaining low reactor water conductivity to mitigate intergranular stress corrosion crack (IGSCC) initiation and growth, as well as taking numerous actions to control radiation source term reduction. The actions taken to control the latter include replacement of the brass condenser tubes and an active cobalt source term reduction plan by eliminating the stellite control rod pins and rollers. These water chemistry improvements at the KKM plant have resulted in lower operating dose rates, lower drywell (shut down) dose rates and mitigation of shroud cracks. It is important to note that KKM is the only plant in the BWR industry that has monitored shroud internal diameter (ID) crack growth rates on a consistent basis using ultrasonic testing (UT) since 1993, thus providing an enormously valuable contribution to the BWR industry's in-plant crack growth rate data base. KKM plant has also installed tie rods in the shroud in 1996, an industry accepted approach. In addition, KKM also implemented NobleChem™ and On-Line NobleChem™ (OLNC) along with low hydrogen injection as additional proactive measures in 2000 and 2005 respectively to mitigate the growth of shroud cracks. There is reasonably clear evidence that since the implementation of OLNC, there is a consistent reduction in shroud crack growth rates showing mitigation of existing cracks. It is also evident that the drywell dose rates are showing a continuing decrease following 60Co source term reductions, DZO and OLNC implementations. This paper

  10. Malheur NWR: Initial Survey Instructions for Water Chemistry/Quality Collection of Water Bodies in Malheur National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This survey provides the baseline understanding of aquatic health in our rivers, lakes, and marshes. The Refuge staff lacks consistent water chemistry measurements,...

  11. Chemistry

    International Nuclear Information System (INIS)

    Research progress is reported in programs on fuel-salt chemistry, properties of compounds in the Li--Te system, Te spectroscopy UF4--H equilibria, porous electrode studies of molten salts, fuel salt-coolant salt reactions, thermodynamic properties of transition-metal fluorides, and properties of sodium fluoroborate. Developmental work on analytical methods is summarized including in-line analysis of molten MSBR fuel, analysis of coolant-salts for tritium, analysis of molten LiF--BeF2--ThF4 for Fe and analysis of LiF--BeF--ThF4 for Te

  12. Secondary side water chemistry pH control strategy improvements

    International Nuclear Information System (INIS)

    Over the years the PWR plant operators were aware of the need of optimizing the pH control strategy in the water-steam cycle with the focus on improvement of steam generator performance with the main goal of reducing the corrosion product ingress into the steam generators and their consequences: SG fouling, SG tube corrosion beneath deposits. To achieve this goal, it becomes necessary to harmonize three requirements: a. High overall pH along the circuit for suppression of general corrosion, requiring a volatile amine to ensure a suitable distribution in steam areas and condenser, and b. High local pH at the water phase of two-phase flow areas, requiring an either rather low volatile amine to ensure high pH in the wet steam water film, or larger amounts of a volatile amine. c. Sufficient amount of hydrazine to ensure reducing conditions in the steam generators. The basic strategy of AREVA NP GmbH (formerly KWU), successfully applied in German nuclear power plants since the late seventies consisted on the achievement of the necessary pH by means of ammonia, as generated by thermal decomposition of hydrazine. By dosing of hydrazine at the necessary amounts to ensure reducing conditions, also sufficient ammonia is generated to achieve a high overall pH along the cycle, being the target pH (25 deg. C) ≥ 9.8 resulting in < 1 ppb Fe in final feed water. This treatment is known as H-AVT (High pH - All Volatile Treatment). Main prerequisite for its application is to have a copper-free system. Eventually, H-AVT started to be applied later at some other western nuclear power plants. In some units, the high condenser exhaust flow rate applied caused a considerable amount of ammonia being removed from the cycle, resulting in too low ammonia concentrations to maintain a sufficiently high pH, making the addition of ammonia necessary. AREVA NP GmbH together with plant operators investigated the possibility of complementing the applied classical H-AVT by addition of an advanced

  13. A Series RCL Circuit Theory for Analyzing Non-Steady-State Water Uptake of Maize Plants

    Science.gov (United States)

    Zhuang, Jie; Yu, Gui-Rui; Nakayama, Keiichi

    2014-10-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths.

  14. Safety regulations regarding to water chemistry in Russia's NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Sharafutdinov, R.B.; Kharitonova, N.L.; Denisova, L.G. [Federal State Institution Scientific and Engineering Centre for Nuclear and Radiation Safety (SEC NRS), Federal Environmental, Industrial and Nuclear Supervision Service of Russia, Moscow (Russian Federation)

    2010-07-01

    The basic directions of further improvement of the regulatory documents with respect to NPP water chemistry (WC) in Russia are considered. Necessity of optimizing of water chemistry regulation is caused by the requirement to ensure the integrity, reliability and availability of the main plant structures, systems and components that have a bearing on safety. For Russia's NPP are determined the limits of safe operation related to coolant quality. These limits for NPP with WWER-1000, WWER-440 and RBMK-1000 are regulated by WC standards and norms prepared by operating organization. The principles, which are used as the basis for regulation of WC quality indicators and main quality standards of coolant for NPPs are considered. Performance data are also provided on chemical indicators of water chemistry quality of operating NPP units. The issues of justification and application of most advanced water chemistries are dealt with. The report describes the current state of Russia's NPP operation safety regulation with regard to water chemistry. The paper describes a tendency of development of regulatory document requirements related to maintenance of NPP unit WC. The Russia Federal Rules and Regulations (FRRs) in the field of nuclear energy use establish a number of requirements to NPP water chemistry (WC) and to systems required for WC maintenance. The objective of these FRRs includes supporting the integrity of various barriers due to the potential corrosion of components, reducing occupational exposures and limiting releases of radioactivity and chemicals into the environment. The structure of documents specifying requirements to water chemistry at nuclear power plants is considered. It's shown, that the realization of the Program of power generation increasing at the nuclear power plants, adopted by Federal Atomic Energy Agency of Russia, including power up rating, life extension and the prospects of commissioning of the advanced power units with WWER-1200

  15. Safety regulations regarding to water chemistry in Russia's NPPs

    International Nuclear Information System (INIS)

    The basic directions of further improvement of the regulatory documents with respect to NPP water chemistry (WC) in Russia are considered. Necessity of optimizing of water chemistry regulation is caused by the requirement to ensure the integrity, reliability and availability of the main plant structures, systems and components that have a bearing on safety. For Russia's NPP are determined the limits of safe operation related to coolant quality. These limits for NPP with WWER-1000, WWER-440 and RBMK-1000 are regulated by WC standards and norms prepared by operating organization. The principles, which are used as the basis for regulation of WC quality indicators and main quality standards of coolant for NPPs are considered. Performance data are also provided on chemical indicators of water chemistry quality of operating NPP units. The issues of justification and application of most advanced water chemistries are dealt with. The report describes the current state of Russia's NPP operation safety regulation with regard to water chemistry. The paper describes a tendency of development of regulatory document requirements related to maintenance of NPP unit WC. The Russia Federal Rules and Regulations (FRRs) in the field of nuclear energy use establish a number of requirements to NPP water chemistry (WC) and to systems required for WC maintenance. The objective of these FRRs includes supporting the integrity of various barriers due to the potential corrosion of components, reducing occupational exposures and limiting releases of radioactivity and chemicals into the environment. The structure of documents specifying requirements to water chemistry at nuclear power plants is considered. It's shown, that the realization of the Program of power generation increasing at the nuclear power plants, adopted by Federal Atomic Energy Agency of Russia, including power up rating, life extension and the prospects of commissioning of the advanced power units with WWER-1200

  16. Formation of calcium naphthenate in water/oil systems, naphthenic acid chemistry and emulsion stability

    OpenAIRE

    Havre, Trond Erik

    2002-01-01

    In recent years the production of crude oils with high amounts of naphthenic acids has increased. Certain problems are related to this type of crudes and a better understanding of the chemistry of the naphthenic acids is therefore of interest.Synthetic model naphthenic acids, as well as commercial mixtures and crude oil naphthenic acids have been utilized to study the chemistry of naphthenic acids. Partitioning of naphthenic acids between oil and water and the dissociation equilibria in water...

  17. Progress and current status in water radiolysis calculation for BWR primary circuit

    International Nuclear Information System (INIS)

    In order to assess the material integrity of the BWR primary components from the viewpoint of material degradation, it has been widely recognized that the radiolysis modeling and the corrosion potential modeling are of vital use for the environmental evaluation of the BWR primary systems. At the last Workshop on LWR Coolant Water Radiolysis and Electrochemistry, summary papers on both modeling discussions were presented. The Hydrogen Water Chemistry Task Team of the Atomic Energy Society of Japan is now discussing standard evaluation procedures of hydrogen water chemistry to guarantee mitigating corrosive conditions for core internals in aged BWRs. This time the progress and current status on the procedures are reported. The radiolysis model should include G-values and reaction rate constants as essential parameters and also deal with plant related parameters such as radiation dose rates. A kind of a sensitivity analysis was performed and the key parameters have been identified. It has been rather a consensus that the radiolysis modeling technique has been well acknowledged as a useful tool. The mixed potential model has been widely used to predict the electrochemical corrosion potential as an important index to evaluate the SCC susceptibility of the materials. In this model the corrosion potential is calculated based on the concentrations of the water radiolysis products and other fluid dynamics parameters as flow velocity, equivalent diameter, etc. Since ECPs at all the necessary points in the BWR primary system are not available, the model calculation is regarded as a necessary tool to predict the effectiveness of environmental mitigation measures such as hydrogen water chemistry. Therefore it is necessary to establish a standard procedure for the evaluation of radiolysis product and the ECP. Recently AECL has issued a data base on the rate constants and G-values. The adoption of those data will be discussed and the comparison of the results to the previous ones

  18. Nondestructive elemental analysis of corrosion and wear products from primary and secondary CANDU water circuits

    International Nuclear Information System (INIS)

    The application of X-ray fluorescence (XRF) for off-line and on-line analysis of corrosion-product transport (CPT) specimens is being evaluated, to monitor corrosion and wear products in CANDU water circuits. The method is suitable for nondestructive analysis of CPT filters from both primary and secondary sides (i.e., radioactive and nonradioactive specimens). The XRF method, the portable analyzer, and the work required to optimize their performance for CPT specimens are described. Measurements performed on station CPT specimens are discussed. Data on crud transport and composition were obtained, in particular iron and lead transport in secondary-side water and iron and zirconium in primary-side water. The possibility and requirements for quasi in-line analysis under operating conditions are also considered. (author)

  19. Numerical simulation of water hammer characteristics for integral reactor primary circuit

    International Nuclear Information System (INIS)

    Based on the method of characteristic line, a set of closed mathematic expressions with reasonable boundary conditions of the nuclear reactor primary circuit has been established. WAHAP program has been developed, and numerical calculation is carried out on the check valve-induced water hammer phenomena in a four pumps paralleled feedwater system during the alternating startup process of parallel pumps. In this paper, we found that the valve disc stroke the valve seat at two different periods and there were two kinds of pressure vibration existed. (authors)

  20. VVER operational experience - effect of preconditioning and primary water chemistry on radioactivity build-up

    International Nuclear Information System (INIS)

    The primary coolant technology approaches currently used in VVER units are reviewed and compared with those used in PWR units. Standard and modified water chemistries differing in boron-potassium control are discussed. Preparation of the VVER Primary Water Chemistry Guidelines in the Czech Republic is noted. Operational experience of some VVER units, operated in the Czech Republic and Slovakia, in the field of the primary water chemistry, and radioactivity transport and build-up are presented. In Mochovce and Temelin units, a surface preconditioning (passivation) procedure has been applied during hot functional tests. The main principles of the controlled primary water chemistry applied during the hot functional tests are reviewed and importance of the water chemistry, technological and other relevant parameters is stressed regarding to the quality of the passive layer formed on the primary system surfaces. The first operational experience obtained in the course of beginning of these units operation is presented mainly with respect to the corrosion products coolant and surface activities. Effect of the initial passivation performed during hot functional tests and the primary water chemistry on corrosion products radioactivity level and radiation situation is discussed. (author)

  1. Water Chemistry Control Technology to Improve the Performance of Nuclear Power Plants for Extended Fuel Cycles

    International Nuclear Information System (INIS)

    Ο To Develop the technology to manage the problems of AOA and radiation, corrosion as long term PWR operation. Ο To Establish the advanced water chemical operating systems. - Development of the proper water chemistry guidelines for long term PWR operation. AOA(Axial Offest Anomaly) has been reported in many PWR plants in the world, including Korea, especially in the plants of higher burn-up and longer cycle operation or power up-rate. A test loop has been designed and made by KAERI, in order to investigate and mitigate AOA problems in Korea. This project included the study of hydrodynamic simulation and the modeling about AOA. The analysis of radioactive crud was performed to investigate of NPPs primary water chemical effect on AOA and to reduce the radioactive dose rate. The high temperature measurement system was developed to on-line monitor of water chemistry in nuclear power plants. The effects of various environmental factors such as temperature, pressure, and flow rate on YSZ-based pH electrode were evaluated for ensuring the accuracy of high-temperature pH measurement. The inhibition technology for fouling and SCC of SG tube was evaluated to establish the water chemistry technology of corrosion control of nuclear system. The high temperature and high pressure crevice chemistry analysis test loop was manufactured to develop the water chemistry technology of crevice chemistry control

  2. Experience with primary hydrazine water chemistry at WWER-440 units of Paks nuclear power plant

    International Nuclear Information System (INIS)

    1. Control measurements during application of hydrazine water chemistry have shown that, after a brief initial rise, the concentration of corrosion products stabilises at a level lower than that observed with the ammonia cycle. 2. In the case of transitional operating conditions, the rise in insoluble corrosion products is lower with hydrazine water chemistry applied than with the ammonia water chemistry. 3. Lowering of the measured values of radioactive surface contamination and of the dose rates measured in the various primary loops of course proceeds on dissimilar levels, but measured values show a distinct downward trend, both for the case of high and low initial values. 4. The amount of liquid radioactive wastes can be reduced by delaying chemical contamination. 5. Using hydrazine water chemistry also considerably reduces re-contamination through radioactive isotopes, as compared to the effects of chemical decontamination or even ammonia water chemistry. 6. Another important financial profit can be gained by hydrazine water chemistry, as it reduces the collective dose. (orig./CB)

  3. Analysis of radionuclide generation in primary circuit water of LVR-15 reactor

    International Nuclear Information System (INIS)

    The LVR-15 reactor is a light water research type reactor, which is situated in Nuclear Research Institute, Rez near Prague. At present the IRT-2M fuel of Russian production with enrichment of 36% is used. In the reactor core there are usually from 28 to 32 fuel assemblies with the total mass about 5 kg of 235U. Reactor is cooled by demineralized water. The maximum thermal power is 10 MW and the reactor is operated in 21-days irradiation cycles, with 8 to 10 cycles per year. The early detection of a damaged fuel assembly in reactor core is one of the most important aspects for safety operation of the reactor and radiation protection of the reactor staff. The indication of damaged fuel assembly can be made e.g. from gas effluents. This paper deals with the method based on the primary circuit water activity measurement. The measurement of primary circuit water is made regularly (weekly) since 1996. Radionuclides in the water are produced by activation of stable nuclides and by fission of fissile nuclides, mainly 235U. From activity values of fission products of 235U and activity of 239Np (activation product of 238U) the enrichment (mass ratio of 235U and 238U) of the irradiated Uranium can be estimated. Finally , from the enrichment one can conclude if the source of fission products is mainly natural Uranium (from demineralized water) or Uranium from fuel assemblies ( contamination of fuel cladding or damage of fuel assembly). During 9 years of measurement, the activities of fission products in primary circuit water have been decreasing, in average. From comparison of theoretical results and measured values of volume activities of fission products and 239Np the enrichment of the irradiated uranium have been estimated. The resulted 39 % enrichment has high uncertainty due to complicated chemical and physical processes inside of the reactor. Despite of this uncertainty ( estimated of factor 2 to 5) the enrichment is much closer to value of fuel enrichment (36 %) than

  4. Characteristics of meaningful chemistry education - The case of water quality

    NARCIS (Netherlands)

    Westbroek, Hanna Barbara

    2005-01-01

    This thesis addresses the question of how to involve students in meaningful chemistry education by a proper implementation of three characteristics of meaningful: a context, a need-to-know approach and attention for student input. The characteristics were adopted as solution strategies for problemat

  5. Water chemistry management in cooling system of research reactor in JAERI

    International Nuclear Information System (INIS)

    The department of research reactor presently operates three research reactors (JRR-2, JRR-3M and JRR-4). For controlling and management of water and gas in each research reactor are performed by the staffs of the research reactor technology development division. Water chemistry management of each research reactor is one of the important subject. The main objects are to prevent the corrosion of water cooling system and fuel elements, to suppress the plant radiation build-up and to minimize the radioactive waste. In this report describe a outline of each research reactor facilities, radiochemical analytical methods and chemical analytical methods for water chemistry management. (author)

  6. PWR Secondary Water Chemistry Control Status: A Summary of Industry Initiatives, Experience and Trends Relative to the EPRI PWR Secondary Water Chemistry Guidelines

    International Nuclear Information System (INIS)

    The latest revision of the EPRI Pressurized Water Reactor (PWR) Secondary Water Chemistry Guidelines was issued in February 2009. The Guidelines continue to focus on minimizing stress corrosion cracking (SCC) of steam generator tubes, as well as minimizing degradation of other major components / subsystems of the secondary system. The Guidelines provide a technically-based framework for a plant-specific and effective PWR secondary water chemistry program. With the issuance of Revision 7 of the Guidelines in 2009, many plants have implemented changes that allow greater flexibility on startup. For example, the previous Guidelines (Revision 6) contained a possible low power hold at 5% power and a possible mid power hold at approximately 30% power based on chemistry constraints. Revision 7 has established a range over which a plant-specific value can be chosen for the possible low power hold (between 5% and 15%) and mid power hold (between 30% and 50%). This has provided plants the ability to establish significant plant evolutions prior to reaching the possible power hold; such as establishing seal steam to the condenser, placing feed pumps in service, or initiating forward flow of heater drains. The application of this flexibility in the industry will be explored. This paper also highlights the major initiatives and industry trends with respect to PWR secondary chemistry; and outlines the recent work to effectively address them. These will be presented in light of recent operating experience, as derived from EPRI's PWR Chemistry Monitoring and Assessment (CMA) program (which contains more than 400 cycles of operating chemistry data). (authors)

  7. Chemistry variations of the secondary circuit aqueous environment reflected in the characteristics of the superficial films formed on the carbon steel components

    International Nuclear Information System (INIS)

    The aim of this paper is to establish correlations between the characteristics of the superficial films formed on the carbon steel components in operation conditions of the secondary circuit of the Cernavoda Nuclear Power Station (NPS) and the specific parameters of the aqueous environment in which these films were formed. The main parameters studied in this paper, specific to a secondary circuit environment, are: the value of pH and the substances used to control it and the oxygen concentration dissolved in the aqueous environment, respectively. These filmed samples by autoclaving were studied by: 1. X rays diffraction method; 2. metallographic microscopy and 3. electrochemical methods such as: potentiodynamic and electrochemical impedance spectroscopy (E.I.S). to establish the correlations between the characteristics of the superficial films and the chemistry of the aqueous environment from the secondary circuit. To create films on the carbon steel samples similarly with those formed on the components during the operation of the NPS secondary circuit, some samples of three types of carbon steel - SA106, SA508 and SA516 - were filmed by autoclaving at 260 deg. C (51 atm) in aqueous environments with given physical and chemical characteristics. Using descaling and gravimetric method, there were established the corrosion kinetics of the carbon steel samples, which include: 1. the global corrosion rate (mg/dm2/day); 2. the global corrosion products formed (mg/dm2); 3. the adherent corrosion film (mg/dm2); 4. the non-adherent corrosion products (mg/dm2), etc. (authors)

  8. Major ion chemistry of the Son River, India: Weathering processes, dissolved fluxes and water quality assessment

    Indian Academy of Sciences (India)

    Chinmaya Maharana; Sandeep Kumar Gautam; Abhay Kumar Singh; Jayanth K Tripathi

    2015-08-01

    River Son, draining diverse lithologies in the subtropical climate of the peninsular sub-basin of the Ganga basin, is one of the major tributaries of the Ganga River. The chemistry of major ions in the surface water of the Son River was studied in detail to determine various source(s) and processes controlling its water chemistry, seasonal and spatial variations in water chemistry, dissolved fluxes and chemical denudation rate (CDR). The study shows that Ca2+, Mg2+ and HCO$^{-}_{3}$ are major ionic species in the river water. Most of the measured parameters exhibit a relatively lower concentration in the post-monsoon as compared to pre-monsoon season. The water chemistry highlights the influence of continental weathering aided by secondary contributions from ground water, saline/alkaline soils and anthropogenic activities in the catchment. Results also reflect the dominance of carbonate weathering over silicate weathering in controlling water composition. The Son River delivers about 4.2 million tons of dissolved loads annually to the Ganga River, which accounts for ∼6% of the total annual load carried by the Ganga River to the Bay of Bengal. The average CDR of the Son River is 59.5 tons km−2 yr−1, which is less than the reported 72 tons km−2 yr−1 of the Ganga River and higher than the global average of 36 tons km−2 yr−1. The water chemistry for the pre-monsoon and post-monsoon periods shows a strong seasonal control on solute flux and CDR values. The water chemistry indicates that the Son River water is good to excellent in quality for irrigation and also suitable for drinking purposes.

  9. Water chemistry and endangered white-clawed Crayfish: a literature review and field study of water chemistry association in Austropotamobius pallipes

    Directory of Open Access Journals (Sweden)

    Haddaway N.R.

    2015-01-01

    Full Text Available Populations of the endangered white-clawed crayfish (Austropotamobius pallipes have rapidly declined in distribution and density in recent decades as a result of invasive crayfish, disease and habitat degradation. The species is thought to be particularly sensitive to water chemistry, and has been proposed as a bio-indicator of water quality. Here we detail the results of a systematic review of the literature regarding the chemistry of waterbodies inhabited by white-clawed crayfish, along with a wide-scale field study of the chemistry of crayfish-inhabited waterbodies in the UK. We use these data to examine potentially significant variables influencing crayfish distribution. Several variables appear to have thresholds that affect crayfish distribution; crayfish presence was associated with high dissolved oxygen, low conductivity, ammonium, sodium, and phosphate, and to a lesser extent low sulphate, nitrate, and total suspended solids. Some variables (magnesium, potassium, sodium, sulphate, nitrate, and total suspended solids may be tolerated at moderate to high concentrations in isolation (indicated by the presence of some populations in high levels of these variables, but suites of chemical conditions may act synergistically in situ and must be considered together. Recent efforts to conserve white-clawed crayfish have included relocations to Ark Sites; novel protected habitats with reduced risk of the introduction of disease, invasive crayfish and habitat degradation. We use our findings to propose the first detailed guidelines for common water chemistry variables of potential Ark Sites for the conservation of the species throughout its European range.

  10. Water chemistry of surface waters affected by the Fourmile Canyon wildfire, Colorado, 2010-2011

    Science.gov (United States)

    McCleskey, R. Blaine; Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    In September 2010, the Fourmile Canyon fire burned about 23 percent of the Fourmile Creek watershed in Boulder County, Colo. Water-quality sampling of Fourmile Creek began within a month after the wildfire to assess its effects on surface-water chemistry. Water samples were collected from five sites along Fourmile Creek (above, within, and below the burned area) monthly during base flow, twice weekly during snowmelt runoff, and at higher frequencies during storm events. Stream discharge was also monitored. Water-quality samples were collected less frequently from an additional 6 sites on Fourmile Creek, from 11 tributaries or other inputs, and from 3 sites along Boulder Creek. The pH, electrical conductivity, temperature, specific ultraviolet absorbance, total suspended solids, and concentrations (dissolved and total) of major cations (calcium, magnesium, sodium, and potassium), anions (chloride, sulfate, alkalinity, fluoride, and bromide), nutrients (nitrate, ammonium, and phosphorus), trace metals (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, strontium, vanadium, and zinc), and dissolved organic carbon are here reported for 436 samples collected during 2010 and 2011.

  11. Effect of Water Chemistry Variations on Corrosion of Zr-Alloys for BWR Applications

    International Nuclear Information System (INIS)

    Two reference water chemistry conditions (60 ppb Zn and 60 μg/cm2 Pt/Rh with either 500 ppb O2 and 500 ppb H2O2, or 150 ppb H2) were chosen for testing at 300 deg. C in refreshed autoclaves. For each reference water chemistry, the potential effects due to three chemical impurities of interest to BWRs (33 ppm Na, 10 ppm Li, and 10 ppm EHC fluid) were evaluated. Zircaloy-2 and GNF-Ziron (a Zr-based alloy with higher Fe additions than Zircaloy-2) cladding tubes were tested and the effects of tubing process variation and pre-filming were investigated. Tested channel materials included Zircaloy-2, Zircaloy-4, GNF-Ziron and NSF (a Zr-based alloy with Sn, Nb and Fe additions). The corrosion weight gain and hydrogen absorption were measured up to 12 months of exposure for a given water chemistry condition. Tests under 150 ppb H2 based water chemistry, with or without chemical impurities, generally resulted in greater amounts of corrosion after 12 month exposure compared with 500 ppb O2 and 500 ppb H2O2 based water chemistries. Of the added chemical impurities, only 33 ppm Na addition produced slightly increased corrosion. Under various test conditions, the presence of a thin pre-film resulted in some initial corrosion benefits, but the benefits were no longer evident after 12 months exposure; however, slight hydrogen benefits remained. For GNF-Ziron cladding, hydrogen absorption was generally lower compared with similarly processed Zircaloy-2 under 150 ppb H2 based water chemistry, when corrosion was generally higher. Of the channel material tested, NSF developed the lowest level of hydrogen absorption, particularly under 150 ppb H2 based water chemistries. (authors)

  12. Assessment of EPRI water chemistry guidelines for new nuclear power plants

    International Nuclear Information System (INIS)

    Water chemistry control technologies for nuclear power plants have been significantly enhanced over the past few decades to improve material and equipment reliability and fuel performance, and to minimize radionuclide production and transport. Chemistry Guidelines have been developed by the Electric Power Research Institute (EPRI) for current operating plants and have been intermittently revised over the past twenty-five years for the protection of systems and components and for radiation management. As new plants are being designed for improved safety and increased power production, it is important to ensure that the designs consider implementation of industry approved water chemistry controls. In parallel, the industry will need to consider and develop updated water chemistry guidelines as well as plant startup and operational strategies based on the advanced plant designs. In 2010, EPRI began to assess chemistry control strategies at advanced plants, based on the Design Control Documents (DCDs), Combined Construction and Operating License Applications (COLA), and operating experiences (where they exist) against current Water Chemistry Guidelines. Based on this assessment, differences between planned chemistry operations at new plants and the current Guidelines will be identified. This assessment will form the basis of future activities to address these differences. The project will also assess and provide, as feasible, water chemistry guidance for startup and hot functional testing of the new plants. EPRI will initially assess the GE-Hitachi/Toshiba ABWR and the Westinghouse AP1000 designs. EPRI subsequently plans to assess other plant designs such as the AREVA U.S. EPR, Mitsubishi Heavy Industries (MHI) U.S. APWR, and GE-Hitachi (GE-H) ESBWR. This paper discusses the 2010 assessments of the ABWR and AP1000. (author)

  13. Chemistry

    International Nuclear Information System (INIS)

    Research and development activities dealing with the chemical problems related to design and ultimate operation of molten-salt reactor systems are described. An experimental test stand was constructed to expose metallurgical test specimens to Te2 vapor at defined temperatures and deposition rates. To better define the chemistry of fluoroborate coolant, several aspects are being investigated. The behavior of hydroxy and oxy compounds in molten NaBF4 is being investigated to define reactions and compounds that may be involved in corrosion and/or could be involved in methods for trapping tritium. Two corrosion products of Hastelloy N, Na3CrF6 and Na5Cr3F14, were identified from fluoroborate systems. The evaluation of fluoroborate and alternate coolants continued. Research on the behavior of hydrogen and its isotopes is summarized. The solubilities of hydrogen, deuterium, and helium in Li2BeF4 are very low. The sorption of tritium on graphite was found to be significant (a few milligrams of tritium per kilogram of graphite), possibly providing a means of sequestering a portion of the tritium produced. Development of analytical methods continued with emphasis on voltammetric and spectrophotometric techniques for the in-line analysis of corrosion products such as Fe2+ and Cr3+ and the determination of the U3+/U4+ ratio in MSBR fuel salt. Similar studies were conducted with the NaBF4--NaF coolant salt. Information developed during the previous operation of the CSTF has been assessed and used to formulate plans for evaluation of in-line analytical methods in future CSTF operations. Electroanalytical and spectrophotometric research suggests that an electroactive protonic species is present in molten NaBF4--NaF, and that this species rapidly equilibrates with a volatile proton-containing species. Data obtained from the CSTF indicated that tritium was concentrated in the volatile species. (JGB)

  14. Water chemistry during startup testing at the latest PWR. Genkai Unit No. 4

    International Nuclear Information System (INIS)

    In Genkai Unit No. 4, the biggest output nuclear plant in Japan with generation capacity of 1,180 MWe, various countermeasures to reduce radiation exposure have been adopted from the design and construction stages, including the use of Alloy TT690. The countermeasures indicated here were designed to reduce the generation of corrosion products and facilitate their removal during shutdown. Improvement of water chemistry during hot functional test (HFT) with H2 and LiOH additives led to form an oxide film in the initial stage of corrosion and metal release. Thus, the concentration of corrosion product was minimized, indicating that the improved HFT water chemistry was effective to radiation source reduction. Both radiation source on primary water system and secondary water chemistry condition of the Genkai Unit No. 4 were thought to have kept very excellent condition even in the startup test stage. These would become more excellent quality in commercial operation through further efforts. (M.N.)

  15. A new concept sensor to determine water chemistry conditions in high temperature water

    International Nuclear Information System (INIS)

    In order to confirm the concept of sensor, responses of the redox potentials of pure metals to the changes in O2 concentration were measured under non-irradiated condition. The obtained results are in follows. 1. The different responses of redox potentials to DO concentrations were obtained for the pure Fe, Zr and Pt electrodes. 2. The possibility of the concept of new array-type sensor to determine the DO concentration was confirmed using Pt, Zr and Fe electrodes. 3. The oxide film might affect the response of array-type sensor. The combination of inert electrodes was required to develop the array-type sensor. 4. In order to evaluate the availability of array-type sensor for the determination of water chemistry condition in reactor coolant, more data is required. (author)

  16. Water Chemistry Control in Reducing Corrosion and Radiation Exposure at PWR Reactor

    International Nuclear Information System (INIS)

    Water chemistry control plays an important role in relation to plant availability, reliability and occupational radiation exposures. Radiation exposures of nuclear plant workers are determined by the radiation rate dose and by the amount maintenance and repair work time Water chemistry has always been, from beginning of operation of power Pressurized Water Reactor, an important factor in determining the integrity of reactor components, fuel cladding integrity and minimize out of core radiation exposures. For primary system, the parameters to control the quality of water chemistry have been subject to change in time. Reactor water coolant pH need to be optimally controlled and be operated in range pH 6.9 to 7.4. At pH lower than 6.9, cause increasing the radiation exposure level and increasing coolant water pH higher than 7.4 will decrease radiation exposure level but increasing risk to fuel cladding and steam generator tube. Since beginning 90 decade, PWR water coolant pH tend to be operated at pH 7.4. This paper will discuss concerning water chemistry development in reducing corrosion and radiation exposure dose in PWR reactor. (author)

  17. Experience with maintenance of feed-water chemistry for FBTR once through steam generator

    International Nuclear Information System (INIS)

    Once through steam generators utilised for fast reactors are critical components requiring stringent control on water quality. This paper details the experience in maintenance of feed water chemistry during various phases of power operation in fast breeder test reactor (FBTR). (author). 1 ref., 2 figs., 1 tab

  18. An Environmental Chemistry Experiment: The Determination of Radon Levels in Water.

    Science.gov (United States)

    Welch, Lawrence E.; Mossman, Daniel M.

    1994-01-01

    Describes a radiation experiment developed to complement a new environmental chemistry laboratory curriculum. A scintillation counter is used to measure radon in water. The procedure relies on the fact that toluene will preferentially extract radon from water. Sample preparation is complete in less than 90 minutes. Because the level of…

  19. Radiation chemistry of high temperature and supercritical water

    International Nuclear Information System (INIS)

    The progresses of the studies on water radiolysis at elevated temperatures and supercritical water are reviewed, with the emphasis on the temperature and density effects on the radiolytic yields of water decomposition products, the reaction rate constants and the spectral properties of hydrated electron. (author)

  20. Water and Life in the International Year of Chemistry

    Science.gov (United States)

    Bernal, Pedro J.

    2011-01-01

    This commentary talks about the worldwide health impact of lack of access to potable water. Household water treatment and storage (HWTS) is described as one approach to improving potable water accessibility in which students and educators can make a contribution to alleviate the problem of lack of access. The author suggests that, as chemists,…

  1. Water chemistry of supercritical pressure water under radiation field. Electrochemical monitoring and thermodynamics calculation

    International Nuclear Information System (INIS)

    This paper describes the program scope of national project, the research plan of electrochemical monitoring and thermodynamics calculation for potential (E)-pH diagrams. Examples of E-pH diagrams are introduced in this paper for Fe/H2O system and Cr/H2O system at supercritical temperatures. 1. A national project for the study on SCW water chemistry under radiation field started under the MEXT fund, including the following three sub-theme: 1) Radiolysis and kinetics of supercritical pressure water, 2) Influence of radiolysis and radiation damage on corrosion, 3) Behavior of corrosion products (CP) on the interface between water and materials. 2. In the sub-theme of CP behavior on the interface, the detailed design of electrochemical monitoring facility and electrochemical cell consists of two flow-through platinum hydrogen electrodes are determined. 3. The review on thermodynamics calculation models for SCW condition revealed the applicability of the revised HKF model and its modified version. The E-pH diagrams drawn with the HKF model exhibited the effect of pressure on solubility at 400degC in consistent with the reported corrosion test. (J.P.N.)

  2. Stable solid state reference electrodes for high temperature water chemistry

    International Nuclear Information System (INIS)

    A solid state electrode capable of providing a stable reference potential under a wide range of temperatures and chemical conditions has been demonstrated. The electrode consists of a zirconia or yttria-stabilized zirconia tube packed with an inorganic polymer electrolyte and a silver/silver chloride sensing element. The sensing element is maintained near room temperature by a passive cooling heat sink. The electrode stability was demonstrated by testing it in high temperature (280 C) aqueous solutions over extended periods of time. This reference electrode is useful in many applications, particularly for monitoring the chemistry in nuclear and fossil power plants

  3. Chemistry and origin of deep ground water in crystalline rocks

    International Nuclear Information System (INIS)

    This report discusses the interactions between water and crystalline rocks and its consequences for the chemical composition of the water. It also treats how flows of different types of water are modified by the rock, and the possible consequences for the ground water near a nuclear waste repository. The focus of the work is the changes in composition that ground water gets at deep levels in the rock. Data from Finnsjoen and Aespoe in Sweden show higher salinity in deep rock, which has been interpreted as a result of marine inflow of water during glaciation. Data from other, deeper boreholes in Finland, Canada, Russia, England and Sweden show that the increasing salinity is a rule and very high at great depths, higher than marine water can produce. Therefore, the deep waters from Finnsjoen and Aespoe are probably very old, and the high salinity a result from geological processes. Differing cation and isotopic composition than seawater also indicate geologic water. Differing theories on the origin of the ground water should be regarded in the safety analysis for a repository. 36 refs, 3 figs, 1 tab

  4. Water chemistry characteristics in small reservoirs of semiarid Tunisia

    OpenAIRE

    Rahaingomanana, Nathalie

    1999-01-01

    The variation of water quality in 24 small reservoirs of semiarid Tunisia was studied in relation to catchment and hydrological context duing two successive and contrasting hydrological years. Measured salinities generally satisfied the various uses. Three geochemical groups were identified based on the water quality during the inflow period. Calcium sulphate water types charachterize reservoirs located in Zeroud and Merguellil catchments. They have the greatest dissolved salt contents and an...

  5. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona--2003-04

    Science.gov (United States)

    Truini, Margot; Macy, Jamie P.; Porter, Thomas J.

    2005-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in the Black Mesa area has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2003, total ground-water withdrawals were 7,240 acre-feet, industrial withdrawals were 4,450 acre-feet, and municipal withdrawals were 2,790 acre-feet. From 2002 to 2003, total withdrawals decreased by 10 percent, industrial withdrawals decreased by 4 percent, and municipal withdrawals decreased by 20 percent. Flowmeter testing was completed for 24 municipal wells in 2004. The median difference between pumping rates for the permanent meter and a test meter for all the sites tested was -2.9 percent. Values ranged from -10.9 percent at Forest Lake NTUA 1 to +7.8 percent at Rough Rock NTUA 2. From 2003 to 2004, water levels declined in 6 of 12 wells in the unconfined part of the aquifer, and the median change was -0.1 foot. Water levels declined in 7 of 11 wells in the confined part of the aquifer, and the median change was -2.7 feet. From the prestress period (prior to 1965) to 2003, the median water-level change for 26 wells was -23.2 feet. Median water-level change were -6.1 feet for 14 wells in the unconfined parts of the aquifer and and -72.1 feet for 12 wells in the confined part. Discharges were measured once in 2003 and once in 2004 at four springs. Discharge stayed the same at Pasture Canyon Spring, increased 9 percent at

  6. Zooplankton mortality due to entrainment in the cooling water circuit of a power station

    International Nuclear Information System (INIS)

    Zooplankton mortality, both the instant (0 h) and delayed (24 h) due to entrainment has been studied at two different locations in the cooling water circuit of Madras Atomic Power Station at Kalpakkam. Among the four dominant groups of zooplankton studied, calanoids the largest organisms (average length 1036±246 μm) with regards to the size as compared to other groups, registered the highest mortality (70.63%). However, the barnacle larvae with their smallest average size (408±105 μm), suffered the lowest mortality. Thus, the mortality occurred corresponded to the average size of the zooplankton groups. The mortality showed significant difference among the four different groups of zooplankton (p=6 ml/day (in terms of displacement volume) is equivalent to 116.2 kg C/Day. (author)

  7. Chemistry of Water Collected From an Unventilated Drift, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Water samples (referred to as puddle water samples) were collected from the surfaces of a conveyor belt and plastic sheeting in the unventilated portion of the Enhanced Characterization of the Repository Block (ECRB) Cross Drift in 2003 and 2005 at Yucca Mountain, Nevada. The chemistry of these puddle water samples is very different than that of pore water samples from borehole cores in the same region of the Cross Drift or than seepage water samples collected from the Exploratory Studies Facility tunnel in 2005. The origin of the puddle water is condensation on surfaces of introduced materials and its chemistry is dominated by components of the introduced materials. Large CO2 concentrations may be indicative of localized chemical conditions induced by biologic activity. (authors)

  8. Recovery of metals from waste printed circuit boards by a mechanical method using a water medium.

    Science.gov (United States)

    Duan, Chenlong; Wen, Xuefeng; Shi, Changsheng; Zhao, Yuemin; Wen, Baofeng; He, Yaqun

    2009-07-15

    Research on the recycling of waste printed circuit boards (PCB) is at the forefront of environmental pollution prevention and resource recycling. To effectively crush waste PCB and to solve the problem of secondary pollution from fugitive odors and dust created during the crushing process, a wet impacting crusher was employed to achieve comminution liberation of the PCB in a water medium. The function of water in the crushing process was analyzed. When using slippery hammerheads, a rotation speed of 1470 rpm, a water flow of 6m(3)/h and a sieve plate aperture of 2.2mm, 95.87% of the crushed product was sized less than 1mm. 94.30% of the metal was in this grade of product. Using smashed material graded -1mm for further research, a Falcon concentrator was used to recover the metal from the waste PCB. Engineering considerations were the liberation degree, the distribution ratio of the metal and a way to simplify the technology. The separation mechanism for fine particles of different densities in a Falcon concentrator was analyzed in detail and the separation process in the segregation and separation zones was deduced. Also, the magnitude of centrifugal acceleration, the back flow water pressure and the feed slurry concentration, any of which might affect separation results, were studied. A recovery model was established using Design-Expert software. Separating waste PCB, crushed to -1mm, with the Falcon separator gave a concentrated product graded 92.36% metal with a recovery of 97.05%. To do this the reverse water pressure was 0.05 MPa, the speed transducer frequency was set at 30 Hz and the feed density was 20 g/l. A flow diagram illustrating the new technique of wet impact crushing followed by separation with a Falcon concentrator is provided. The technique will prevent environmental pollution from waste PCB and allow the effective recovery of resources. Water was used as the medium throughout the whole process. PMID:19121892

  9. Effects of hydrogen water chemistry on radiation field buildup in BWRs

    International Nuclear Information System (INIS)

    A number of boiling water reactor (BWR) plants worldwide are currently operating under hydrogen water chemistry (HWC). In some reactors, when switching from normal water chemistry (NWC) to HWC, an increase in the recirculation piping dose rates has been observed. Understanding the key factors which affect the dose rate increase is the subject of our current investigation. Laboratory experiments have been conducted under controlled chemistry conditions to examine the rates of 60Co deposition and the characteristic of oxide films formed on stainless steel surfaces. The activity buildup data obtained from two operating BWRs are carefully reviewed and discussed in this paper. Based on both laboratory and reactor data, a plausible mechanism of enhanced activity buildup under HWC conditions is hypothesized. (orig.)

  10. Development of High Temperature Chemistry Measurement System for Establishment of On-Line Water Chemistry Surveillance Network in Nuclear Power Plant

    International Nuclear Information System (INIS)

    An integrated high-temperature water chemistry sensor (pH, Eredox) was developed for the establishment of the on-line water chemistry surveillance system in nuclear power plants. The basic performance of the integrated sensor was confirmed in high-temperature (280 .deg. C, 150kg/m2) lithium borate solutions by using the relationship between the concentration of lithium ion and pH-Eredox values. Especially, the effects of various environmental factors such as temperature, pressure, and flow rate on YSZ-based pH electrode were evaluated for ensuring the accuracy of high-temperature pH measurement. And the relationships between each water chemistry factor (pH, redox potential, electrical conductivity) were induced for enhancing the credibility of water chemistry measurement. In addition, on the basis of the evaluation of a nuclear plant design company, we suggested potential installation positions of the measurement system in a nuclear power plant

  11. Interpretation of corrosion potential data from boiling-water reactors under hydrogen water chemistry conditions

    International Nuclear Information System (INIS)

    A method was devised to estimate electrochemical conditions at the entrance to the recirculation piping of a boiling water reactor under hydrogen water chemistry (HWC) conditions from electrochemical corrosion potential (ECP) measurements made in remote autoclaves. The technique makes use of the mixed potential model to estimate ECP in the autoclaves and compares estimates to measured values in an optimization on the concentrations of hydrogen peroxide and oxygen in the recirculation system. The algorithm recognizes that H2O2 decomposes in sampling lines and that transit times between the recirculation system and monitoring points depend upon flow rates and sampling line diameters. An analysis was made of ECP data from three monitoring locations in the Barseback BWR in Sweden, as a function of H2 concentration in the feedwater for two flow rates (5,500 kg/s and 6,300 kg/s for the four recirculation loops). HWC did not displace ECP below a critical value of -0.23 VSHE at the lower flow rate until the reactor water [H2] exceeded 0.15 ppm, corresponding to a feedwater H2 level of > 0.93 ppm. At the higher flow rate of 6,300 kg/s (divided equally between four recirculation loops), protection was not predicted until the feedwater [H2] exceeded 1.2 ppm, corresponding to a reactor water [H2] of ∼ 0.195 ppm. The difference was attributed to the greater persistence of H2O2 at high feedwater [H2] at the higher flow rate, possibly because of the lower transit time from the core to the recirculation system

  12. Chemistry and radiative transfer of water in cold, dense clouds

    OpenAIRE

    Keto, E.; Rawlings, J.; Caselli, P.

    2014-01-01

    The Herschel Space Observatory's recent detections of water vapor in the cold, dense cloud L1544 allow a direct comparison between observations and chemical models for oxygen species in conditions just before star formation. We explain a chemical model for gas phase water, simplified for the limited number of reactions or processes that are active in extreme cold ($

  13. Water chemistry and antimicrobial treatment in poultry processing

    Science.gov (United States)

    This study examined the influence of calcium and magnesium ions in process water on the solubility of trisodium phosphate. Water used in poultry processing operations may be treated with sanitizers such as trisodium phosphate to reduce microbial activity and the risk of contamination. This occurs wh...

  14. Analysis of changes in stream water chemistry following forest management practices in Darabkola forest

    OpenAIRE

    Mananeh Akbarimehr; Seyed Ataollah Hosseini; Seyed Mohammad Hodjati; Fatemeh Shariati

    2016-01-01

    Analysis of changes in stream water chemistry following forest management practices in Darabkola forestAbstract: Forest management practices such as road construction and harvesting may substantially alter the quality of water. The main concern of this investigation was to consider the influence of passed time from logging operation on stream water quality parameters. Six Stream crossings (culverts) with two logging treatments were implemented in three replications on permanent haul roads for...

  15. Comprehensive evaluation of primary circuit water regime of Paks VVER-440 units

    International Nuclear Information System (INIS)

    Analyses of nearly in total 70 operation year experiences of primary circuit water regimes of the four VVER 440 types nuclear units of Paks Nuclear Power Plant had been performed by us. The units started to operate with K / NH3 water regime developed for this type of reactor, on which improvements was performed in the years between 1992-95. As the results of the development instead of ammonia we dose hydrazine into the coolant. From one part of the hydrazine through a thermal and radiolytic decay N2H4→NH3→H2 we maintain the desired H2 level, on the other hand the hydrazine excesses is suitable for supporting the reduction of physical - chemical conditions stability. The radioactive contamination of units' out-of-core surfaces with this can be reduced and the corrosion products in case of transient periods (unit starting, shutdown) are increasing in lower level. In our study we are presenting the operation history of the units and we are performing the evaluation of the coolant and surfaces chemical-radiochemical conditions. We are giving comparison for characteristics which is typical for this type water regime. We are using the correlation for the evaluation which are being between measurable ratio of corrosion products on the surfaces and that of the measured ones in the coolant during output of operation and during the shutdowns. (author)

  16. Corrosion-erosion in secondary circuits. Investigations and remedies

    International Nuclear Information System (INIS)

    The corrosion-erosion phenomenon of EDF PWR units operating involved the study of the roles of water chemistry, temperature and flow conditions on the phenomenon. The nature of the material has also been taken into account. The solutions chosen are the secondary circuit water conditioning (morpholine) and the material used (Z2CN18-10). 8 refs

  17. Analytical chemistry in water quality monitoring during manned space missions

    Science.gov (United States)

    Artemyeva, Anastasia A.

    2016-09-01

    Water quality monitoring during human spaceflights is essential. However, most of the traditional methods require sample collection with a subsequent ground analysis because of the limitations in volume, power, safety and gravity. The space missions are becoming longer-lasting; hence methods suitable for in-flight monitoring are demanded. Since 2009, water quality has been monitored in-flight with colorimetric methods allowing for detection of iodine and ionic silver. Organic compounds in water have been monitored with a second generation total organic carbon analyzer, which provides information on the amount of carbon in water at both the U.S. and Russian segments of the International Space Station since 2008. The disadvantage of this approach is the lack of compound-specific information. The recently developed methods and tools may potentially allow one to obtain in-flight a more detailed information on water quality. Namely, the microanalyzers based on potentiometric measurements were designed for online detection of chloride, potassium, nitrate ions and ammonia. The recent application of the current highly developed air quality monitoring system for water analysis was a logical step because most of the target analytes are the same in air and water. An electro-thermal vaporizer was designed, manufactured and coupled with the air quality control system. This development allowed for liberating the analytes from the aqueous matrix and further compound-specific analysis in the gas phase.

  18. VGB water chemistry guideline for LWR type reactors

    International Nuclear Information System (INIS)

    The guideline for LWRs explains the quality standards to be met by the reactor feedwater and the primary water of BWR type reactors, and by the cooling water, steam generator feedwater and steam generator primary water of PWR type reactors. It also specifies quality standards for make-up water and steam used for the operation of turbines in LWR type power plant, which are subject to the same water purity requirements as fossil fueled power plant. The quality criteria are given as reference values, sometimes accompanied by values referring to specified normal operation, or limit values. The guideline applies to long-term operation, i.e. to the operating conditions at constant load. According to current knowledge and data, observation of the reference data given will exclude disturbance in the water or steam systems of reactors, steam generators and steam turbines. Certain operating conditions, such as load change or start-up and shut-down, may have effects on the water or steam quality which must not exceed the limit values. (orig./HP)

  19. Radon, volatile organic compounds and water chemistry in springs around Popocatepetl volcano, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, N.; Pena, P.; Lopez, M.B.E.; Cisniega, G. [Inst. Nacional de Investigaciones Nucleares, Mexico D.F. (Mexico); Valdes, C.; Armienta, M.A.; Mena, M. [Inst. de Geofisica, UNAM, Ciudad Univ., Mexico D.F. (Mexico)

    2003-07-01

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs is analysed as a function of the 2002-2003 volcanic activity. Soil radon indicated fluctuations related both to the meteorological and sporadic explosive events. Groundwater radon showed essentially differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period indicating differences between springs. No anthropogenic pollution from volatile organic compounds was observed. (orig.)

  20. Radon, volatile organic compounds and water chemistry in springs around Popocatepetl volcano, Mexico

    International Nuclear Information System (INIS)

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs is analysed as a function of the 2002-2003 volcanic activity. Soil radon indicated fluctuations related both to the meteorological and sporadic explosive events. Groundwater radon showed essentially differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period indicating differences between springs. No anthropogenic pollution from volatile organic compounds was observed. (orig.)

  1. Study on the influence of water chemistry on fuel cladding behaviour of LWR in Japan

    International Nuclear Information System (INIS)

    This article presents the results of the study on the influence of water chemistry on fuel cladding behaviour, which has been performed for more than ten years on BWRs and PWRs in Japan. The post irradiation examination (P.I.E.) program of commercial reactor fuel assembly which was explained at Tokyo meeting in 1981 includes an investigation of the characteristics and build-up conditions of crud deposited on mainly BWR fuel cladding. This article also provides a summary of the results of the investigation and shows how the results are utilized for establishing effective water chemistry measures

  2. High pressure reactor water loop for the experimental studies in the field of water chemistry and corrosion

    International Nuclear Information System (INIS)

    At the Nuclear Research Institute in Rez, an experimental reactor pressurized-water loop was built up on basis of a plan of technical development of nuclear power stations with PWR's. This loop is intended for further research and control of conditions in reactor circuits exposed to radiation. The loop (RVS-3) comprises a closed pressurized-water circuit with forced circulation and has a test section located in the core of the VVR-S type reactor, and filtration and measuring circuits. The loop is so equipped that it is possible to operate the loop with the following nominal parameters: working overpressure 15.7 MPa; working temperature 350 deg. C; working medium chemically treated water; flowrate 10,000 kg/hr. The paper summarizes some results of experimental work carried out in NRI during the recent period in the field of electromagnetic filter development, technology of boric acid control and remote electro-chemical methods of measurement of instantaneous corrosion rate of materials. The results of the electromagnetic filter efficiency testing and the development work on the boric acid control by the thermal regeneration of strong base anion resins are presented. The results of the preliminary tests of corrosion of fuel cladding material (zirconium alloy Zr-Nb) in an out-of-pile loop with parameters corresponding to PWR primary circuit is also included. (author)

  3. A case study of water chemistry and design of de-mineralized water plant at HWP-Kota

    International Nuclear Information System (INIS)

    This paper deals with the development of the chemistry parameters of process feed water used for exchange unit (XU) for initial enrichment of heavy water as part of production process at HWP-K. It also highlights the benefits accrued by the effective control of chemistry parameters in the form of improved feed processing rate, sustained and trouble free operation resulting in higher heavy water production at lower energy and production cost. Further reduction in cost of producing de-mineralized quality water can be achieved by adopting layered resin bed which is a new concept where a layer of weak resin is put on top of strong resin with similar characteristics in a single vessel. The benefit of stoichiometric efficiency of regeneration of weak resins is fully utilised in reducing the consumption of regenerants while retaining ability of strong resin to remove weak ions thus maintaining quality of processed water as same. (author)

  4. Concrete durability: physical chemistry of the water attack

    International Nuclear Information System (INIS)

    Cement paste constitutes an basic medium, thermodynamically stable for high pH's. For this reason, water constitutes an aggressive environment. For hydraulic structures, or nuclear waste disposal, water must be considered as a 'chemical loading'. In the short- and medium-term water-degradation of cement paste is principally due to transport of matter between the healthy zone and the aggressive solution through diffusion of ionic species from the interstitial solution of the cement paste. In the long-term, dissolution of the surface may occur. Various cement pastes were prepared and leached with continually demineralized water. After a critical time, which depends on the type of paste, the dissolution of the surface layer in contact with water will control the degradation kinetics. The diffusive and chemical properties of the degraded layer are therefore fundamental for the prediction of the long-term behaviour of concrete in water. 29Si Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) combined with 27A1 MAS NMR and 57Fe Moessbauer spectroscopy indicate that the superficial layer is formed by a CSH with a molecular structure near from the tobermorite mineral. Nuclear magnetic resonance techniques allow us to demonstrate the fundamental role of cationic substitutions occurring in the CSH during degradation on the superficial layer solubility. Our experimental results were used to model the cement paste behaviour taking into account the diffusion and the dissolution of the material. (author)

  5. Removal of sediment and bacteria from water using green chemistry.

    Science.gov (United States)

    Buttice, Audrey L; Stroot, Joyce M; Lim, Daniel V; Stroot, Peter G; Alcantar, Norma A

    2010-05-01

    Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl(2) was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>10(8) cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available. PMID:20369814

  6. Chemistry and Radiative Transfer of Water in Cold, Dense Clouds

    CERN Document Server

    Keto, Eric; Caselli, Paola

    2014-01-01

    The Herschel Space Observatory's recent detections of water vapor in the cold, dense cloud L1544 allow a direct comparison between observations and chemical models for oxygen species in conditions just before star formation. We explain a chemical model for gas phase water, simplified for the limited number of reactions or processes that are active in extreme cold ($<$ 15 K). In this model, water is removed from the gas phase by freezing onto grains and by photodissociation. Water is formed as ice on the surface of dust grains from O and OH and released into the gas phase by photodesorption. The reactions are fast enough with respect to the slow dynamical evolution of L1544 that the gas phase water is in equilibrium for the local conditions thoughout the cloud. We explain the paradoxical radiative transfer of the H$_2$O ($1_{10}-1_{01}$) line. Despite discouragingly high optical depth caused by the large Einstein A coefficient, the subcritical excitation in the cold, rarefied H$_2$ causes the line brightnes...

  7. Coagulation chemistries for silica removal from cooling tower water.

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  8. Chemistry of snow and lake water in Antarctic region

    Indian Academy of Sciences (India)

    Kaushar Ali; Sunil Sonbawane; D M Chate; Devendraa Siingh; P S P Rao; P D Safai; K B Budhavant

    2010-12-01

    Surface snow and lake water samples were collected at different locations around Indian station at Antarctica, Maitri, during December 2004-March 2005 and December 2006-March 2007.Samples were analyzed for major chemical ions. It is found that average pH value of snow is 6.1. Average pH value of lake water with low chemical content is 6.2 and of lake water with high chemical content is 6.5.The Na+ and Cl− are the most abundantly occurring ions at Antarctica. Considerable amount of SO$^{2-}_{4}$ is also found in the surface snow and the lake water which is attributed to the oxidation of DMS produced by marine phytoplankton.Neutralization of acidic components of snow is mainly done by NH$^{+}_{4}$ and Mg2+. The Mg2+, Ca2+ and K+ are nearly equally effective in neutralizing the acidic components in lake water.The NH$^{+}_{4}$ and SO$^{2-}_{4}$ occur over the Antarctica region mostly in the form of (NH4)2SO4.

  9. Efficacy of biofouling control measures in cooling water circuits of MAPS

    International Nuclear Information System (INIS)

    The Madras Atomic Power Station (MAPS) operates on a once through mode using seawater at the rate of 35 m3s-1 for condenser cooling purposes. Low level continuous chlorination (0.2 ± 0.1 mg L-1 TRO) and twice a week booster dosing (0.4 ± 0.2 mg L-1 TRO) for eight hours is practiced. In addition active bromide is being dosed ahead of the process seawater heat exchangers, 0.15 - 0.2 mg L-1for fouling control. Biofouling load in the cooling water circuits of UNIT-2 after a period of 24 months of operation was assessed during maintenance shutdown with a view to assess the efficacy of present chlorination regime. Different sections of the cooling circuit have unique geometries, structural materials, flow paths and environmental conditions (velocity, temperatures and concentration of biocides). The fouling community at the offshore intake well comprised of green mussels (Perna viridis) with a loading of 11.1 kg m2 y-1. Fouling load in the pump chamber (suction end) was found to be 8.7 kg m2 y-2, whereas the load in the discharge conduit of the pumps was 4.1 kg m2 y-2. From the pump house the water is pumped through circular concrete conduits (9.9 kg m2 y-2) to the main condensers. Before reaching the main condensers the water passes through a valve pit comprising of circular mild steel sections (7.6 kg m2 y-2). The main condenser inlet water box was relatively less fouled and was found to be dominated by the barnacle B. reticulatus with a load of 1.0 kg m2 y-2. Compared to the main condenser section, the load in concrete conduits feeding the process water heat exchangers was marginally less (8.3 kg m2 y-2) with barnacle Megabalanus tintinnabulum recorded in addition to those observed in the main condenser conduits. The loads in the mild steel pipe sections (after bromide dosing) were about 8.5 kg m2 y-2, indicating the inadequacy of the biocide in combating fouling. From this point the water passes through a rectangular concrete conduit (header) before entering the

  10. SPENT NUCLEAR FUEL STORAGE BASIN WATER CHEMISTRY: ELECTROCHEMICAL EVALUATION OF ALUMINUM CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Hathcock, D

    2007-10-30

    The factors affecting the optimal water chemistry of the Savannah River Site spent fuel storage basin must be determines in order to optimize facility efficiency, minimize fuel corrosion, and reduce overall environmental impact from long term spent nuclear fuel storage at the Savannah River Site. The Savannah River National Laboratory is using statistically designed experiments to study the effects of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, and Cl{sup -} concentrations on alloys commonly used not only as fuel cladding, but also as rack construction materials The results of cyclic polarization pitting and corrosion experiments on samples of Al 6061 and 1100 alloys will be used to construct a predictive model of the basin corrosion and its dependence on the species in the basin. The basin chemistry model and corrosion will be discussed in terms of optimized water chemistry envelope and minimization of cladding corrosion.

  11. Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide.

    Science.gov (United States)

    Jin, Sung Hun; Kang, Seung-Kyun; Cho, In-Tak; Han, Sang Youn; Chung, Ha Uk; Lee, Dong Joon; Shin, Jongmin; Baek, Geun Woo; Kim, Tae-il; Lee, Jong-Ho; Rogers, John A

    2015-04-22

    This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants. PMID:25805699

  12. Analysis based on the diffusion model for saturation silica gel with water vapor at conservation units steam circuit TPP

    Science.gov (United States)

    Goldaev, Sergey; Khushvaktov, Alisher

    2015-01-01

    A quantitative analysis of the diffusion model dehumidifying air in the steam circuit of TPP, with a layer of silica gel. Showed that such an approximation, supplemented the experimental value of the coefficient of free diffusion identified by the developed method gives reliable values for the concentration of water vapor absorption over time.

  13. Analysis based on the diffusion model for saturation silica gel with water vapor at conservation units steam circuit TPP

    Directory of Open Access Journals (Sweden)

    Goldaev Sergey

    2015-01-01

    Full Text Available A quantitative analysis of the diffusion model dehumidifying air in the steam circuit of TPP, with a layer of silica gel. Showed that such an approximation, supplemented the experimental value of the coefficient of free diffusion identified by the developed method gives reliable values for the concentration of water vapor absorption over time.

  14. Photocatalytic water splitting with acridine dyes: Guidelines from computational chemistry

    Science.gov (United States)

    Liu, Xiaojun; Karsili, Tolga N. V.; Sobolewski, Andrzej L.; Domcke, Wolfgang

    2016-01-01

    The photocatalytic splitting of water into Hrad and OHrad radicals in hydrogen-bonded chromophore-water complexes has been explored with computational methods for the chromophores acridine orange (AO) and benzacridine (BA). These dyes are strong absorbers within the range of the solar spectrum. It is shown that low-lying charge-transfer excited states exist in the hydrogen-bonded AOsbnd H2O and BAsbnd H2O complexes which drive the transfer of a proton from water to the chromophore, which results in AOHradsbnd OHrad or BAHradsbnd OHrad biradicals. The AOHrad and BAHrad radicals possess bright ππ∗ excited states with vertical excitation energies near 3.0 eV which are predissociated by a low-lying repulsive πσ∗ state. The conical intersections of the πσ∗ state with the ππ∗ excited states and the ground state provide a mechanism for the photodetachment of the H-atom by a second photon. Our results indicate that AO and BA are promising chromophores for water splitting with visible light.

  15. Corrosion induced clogging and plugging in water-cooled generator cooling circuit

    International Nuclear Information System (INIS)

    Water-cooled electrical generators have been experienced corrosion-related problems that are restriction of flow through water strainers caused by collection of excessive amounts of copper corrosion products (''clogging''), and restriction of flow through the copper strands in the stator bars caused by growth or deposition of corrosion products on the walls of the hollow strands (''plugging''). These phenomena result in unscheduled shutdowns that would be a major concern because of the associated loss in generating capacity. Water-cooled generators are operated in one of two modes. They are cooled either with aerated water (dissolved oxygen >2 ppm) or with deaerated water (dissolved oxygen <50 ppb). Both modes maintain corrosion rates at satisfactorily low levels as long as the correct oxygen concentrations are maintained. However, it is generally believed that very much higher copper corrosion rates result at the intermediate oxygen concentrations of 100-1000 ppb. Clogging and plugging are thought to be associated with these intermediate concentrations, and many operators have suggested that the period of change from high-to-low or from low-to-high oxygen concentration is particularly damaging. In order to understand the detailed mechanism(s) of the copper oxide formation, release and deposition and to identify susceptible conditions in the domain of operating variables, a large-scale experiments are conducted using six hollow strands of full length connected with physico-chemically scaled generator cooling water circuit. To ensure a close simulation of thermal-hydraulic conditions in a generator stator, strands of the loop will be ohmically heated using AC power supply. Experiments is conducted to cover oxygen excursions in both high dissolved oxygen and low dissolved oxygen conditions that correspond to two representative operating condition at fields. A thermal upset condition is also simulated to examine the impact of thermal stress. During experiments

  16. The chemistry of feedwater for boiling-water and pressurized-water reactors

    International Nuclear Information System (INIS)

    In a nuclear power plant the purity of the feedwater depends largely on whether a condensate polishing plant is provided, whether the loop is conditioned and on the presence of corrosion products originating in the materials from which the loop is made. The feedwater specification depends on the type of steam generator used. The article defines the characteristic parameters of a condensate polishing plant (CPP), such as the 'degree of polishing' and 'practical exchange capacity of the resins' and indicates how they can be determined. In pressurized-water reactors (PWR) the feedwater is normally conditioned with hydrazine. Measurements are quoted to demonstrate that, in contrast to conventional plants, the point of injection is immaterial as regards the copper content of the feedwater. Moreover, the iron content of the feedwater of a PWR can be reduced by using cyclic amines. The feedwater chemistry of a BWR is discussed by referring to oxygen, iron and copper measurements. The authors show that in loops in which the feed-heater condensate is pumped forwards and where a feedwater tank is provided, the stipulated purity of the feedwater can be attained by suitable measures (such as mechanical filtration, prevention of erosion-corrosion, and so on). (Auth.)

  17. Water chemistry in secondary side of cne candu steam generators and their related degradation processes

    International Nuclear Information System (INIS)

    This paper presents a brief overview of steam generator functional parameters of nuclear power plants how use PWR (Pressurized Water Reactor) and PHWR (Pressurized Heavy Water Reactor) reactors, followed by a description of fundamental aspects on steam generator degradation and water chemistry in the secondary side, and also, water chemistry improvement by controlling ph. During operating life, cooling radioactive contamination occurs, but water conditions must be maintained inside specific ranges. Feedwater must be maintained as free from impurities as possible. This requirement involves careful attention to the entire system through which the water flows, either in the form of steam or water, for even though water is used as feedwater be pure at the same time of its entry into the system, it may absorb impurities from the various parts of the installation. Specific attention should be directed to possible points of water leakage from the service water system, as in the main and auxiliary condensers. Feedwater must be treated to maintain the required water conditions. As the concentration of the impurities in deposits increase, the ph can shift locally in these areas to acidic or alkaline conditions, entering in a ph range where initiation of corrosion phenomena cannot be longer excluded. By maintaining of sufficiently reducing conditions, the occurrence of certain corrosion mechanisms will be excluded (like pitting), but certain forms of steam generator tube corrosion may still occur. (authors)

  18. Role(s) of adsorbed water in the surface chemistry of environmental interfaces.

    Science.gov (United States)

    Rubasinghege, Gayan; Grassian, Vicki H

    2013-04-18

    The chemistry of environmental interfaces such as oxide and carbonate surfaces under ambient conditions of temperature and relative humidity is of great interest from many perspectives including heterogeneous atmospheric chemistry, heterogeneous catalysis, photocatalysis, sensor technology, corrosion science, and cultural heritage science. As discussed here, adsorbed water plays important roles in the reaction chemistry of oxide and carbonate surfaces with indoor and outdoor pollutant molecules including nitrogen oxides, sulfur dioxide, carbon dioxide, ozone and organic acids. Mechanisms of these reactions are just beginning to be unraveled and found to depend on the details of the reaction mechanism as well as the coverage of water on the surface. As discussed here, adsorbed water can: (i) alter reaction pathways and surface speciation relative to the dry surface; (ii) hydrolyze reactants, intermediates and products; (iii) enhance surface reactivity by providing a medium for ionic dissociation; (iv) inhibit surface reactivity by blocking sites; (v) solvate ions; (vi) enhance ion mobility on surfaces and (vii) alter the stability of surface adsorbed species. In this feature article, drawing on research that has been going on for over a decade on the reaction chemistry of oxide and carbonate surfaces under ambient conditions of temperature and relative humidity, a number of specific examples showing the multi-faceted roles of adsorbed water are presented. PMID:23417201

  19. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    Directory of Open Access Journals (Sweden)

    S. W. Lyon

    2008-10-01

    Full Text Available Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State. Three distance definitions (or metrics were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  20. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    Directory of Open Access Journals (Sweden)

    S. W. Lyon

    2008-06-01

    Full Text Available Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State. Three distance definitions (or metrics were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  1. Water chemistry and phytoplankton field and laboratory procedures

    Energy Technology Data Exchange (ETDEWEB)

    Davis, C.O.; Simmons, M.S. (eds.)

    1979-12-01

    The purpose of this manual is to serve as a guide for persons using these techniques in water quality studies and as a written record of the methods used in this laboratory at this time. It is anticipated that the manual will be updated frequently as new methods are added and the present ones are further refined. The present methods are all used routinely and have been in regular use for a year or longer. This manual is specifically written as a guide for the collection and analysis of lake water samples from the Laurentian Great Lakes. However, all of the analytical methods are easily adapted for laboratory culture or small lake studies. The descriptions contained in this manual are designed primarily as users guides oriented to the equipment available at the Great Lakes Research Division, and as most of the methods are taken from the literature, the reader is referred to the original articles for a more detailed discussion of the methods.

  2. Water chemistry responses to hydraulic manipulation of an agricultural wetland

    Science.gov (United States)

    Powers, S.; Stanley, E. H.

    2011-12-01

    Small impoundments are often crucial factors for the movement of sediment, organic matter, water-borne nutrients, and toxic materials through river networks. By recent accounting, at least 2.6 million small artificial water bodies exist in the US alone. A large proportion of those structures occur in regions with high intensity of agriculture, such as in the Midwestern grain belt. While small impoundments are aging structures which appear to serve few purposes, some hold ecological and biogeochemical value as artificial wetlands. We documented instantaneous net fluxes of solute (chloride, sulfate, nitrate, ammonium, and soluble reactive phosphorus) through an artificial flow-through wetland in agricultural southern Wisconsin over 6 years which spanned removal of a small dam. Phased dewatering and dam removal ultimately converted the artificial wetland to a canal-like state (increase in mean water velocity from 0.08 to 0.22 m s-1). Mean net flux for chloride across the system averaged nearly 0 g d-1, indicating conservative transport and successful characterization of hydrology. In contrast, net fluxes for other solute forms were altered following loss of the wetland: a persistent net sulfate sink (5-10% of inputs retained), suggestive of sulfate-reducing bacteria, was reduced; seasonal (summer) net sinks for nitrate and ammonium, suggestive of uptake by algae and denitrifying bacteria, were reduced; temporal variability for the net flux of soluble reactive phosphorus was reduced. Overall, loss of the artificial wetland caused by dam removal shifted seasonal and annual net fluxes of biologically available solute toward export. Nutrient retention by artificial wetlands could be important for elemental budgets in regions which have high nutrient loading to surface and ground water.

  3. Kinugasa Reactions in Water: From Green Chemistry to Bioorthogonal Labelling

    OpenAIRE

    Mariya Chigrinova; Douglas A. MacKenzie; Allison R. Sherratt; Lawrence L. W. Cheung; John Paul Pezacki

    2015-01-01

    The Kinugasa reaction has become an efficient method for the direct synthesis of β-lactams from substituted nitrones and copper(I) acetylides. In recent years, the reaction scope has been expanded to include the use of water as the solvent, and with micelle-promoted [3+2] cycloadditions followed by rearrangement furnishing high yields of β-lactams. The high yields of stable products under aqueous conditions render the modified Kinugasa reaction amenable to metabolic labelling and bioorthogona...

  4. Random Phase Approximation in Surface Chemistry: Water Splitting on Iron.

    Science.gov (United States)

    Karlický, František; Lazar, Petr; Dubecký, Matúš; Otyepka, Michal

    2013-08-13

    The reaction of water with zero-valent iron (anaerobic corrosion) is a complex chemical process involving physisorption and chemisorption events. We employ random phase approximation (RPA) along with gradient-corrected and hybrid density functional theory (DFT) functionals to study the reaction of water with the Fe atom and Fe(100) surface. We show that the involvement of the exact electron exchange and nonlocal correlation effects in RPA improves the description of all steps of the reaction on the Fe surface with respect to standard [meaning local density approximation (LDA) or generalized gradient approximation (GGA)] DFT methods. The reaction profile calculated by range-separated hybrid functional HSE06 agrees reasonably well with the RPA profile, which makes HSE06 a computationally less demanding alternative to RPA. We also investigate the reaction of the Fe atom with water using DFT, RPA, and coupled-cluster through the perturbative triples complete basis set [CCSD(T)-3s3p-DKH/CBS] method. Local DFT methods significantly underestimate reaction barriers, while the reaction kinetics and thermodynamics from RPA agree with the reference CCSD(T) data. Both systems, i.e., the Fe atom and Fe(100), provide the same reaction mechanism, indicating that anaerobic corrosion is a stepwise process involving one-electron steps, with the first reaction step (formation of the HFeOH intermediate) representing the rate-limiting step. PMID:26584120

  5. Advanced analytical techniques for boiling water reactor chemistry control

    International Nuclear Information System (INIS)

    The analytical techniques applied can be divided into 5 classes: OFF-LINE (discontinuous, central lab), AT-LINE (discontinuous, analysis near loop), ON-LINE (continuous, analysis in bypass). In all cases pressure and temperature of the water sample are reduced. In a strict sense only IN-LINE (continuous, flow disturbance) and NON-INVASIVE (continuous, no flow disturbance) techniques are suitable for direct process control; - the ultimate goal. An overview of the analytical techniques tested in the pilot loop is given. Apart from process and overall water quality control, standard for BWR operation, the main emphasis is on water impurity characterization (crud particles, hot filtration, organic carbon); on stress corrosion crackling control for materials (corrosion potential, oxygen concentration) and on the characterization of the oxide layer on austenites (impedance spectroscopy, IR-reflection). The above mentioned examples of advanced analytical techniques have the potential of in-line or non-invasive application. They are different stages of development and are described in more detail. 28 refs, 1 fig., 5 tabs

  6. Governing chemistry of cellulose hydrolysis in supercritical water.

    Science.gov (United States)

    Cantero, Danilo A; Bermejo, M Dolores; Cocero, M José

    2015-03-01

    At extremely low reaction times (0.02 s), cellulose was hydrolyzed in supercritical water (T=400 °C and P=25 MPa) to obtain a sugar yield higher than 95 wt%, whereas the 5-hydroxymethylfurfural (5-HMF) yield was lower than 0.01 wt %. If the reaction time was increased to 1 s, the main product was glycolaldehyde (60 wt%). Independently of the reaction time, the yield of 5-HMF was always lower than 0.01 wt%. To evaluate the reaction mechanism of biomass hydrolysis in pressurized water, several parameters (temperature, pressure, reaction time, and reaction medium) were studied for different biomasses (cellulose, glucose, fructose, and wheat bran). It was found that the H(+) and OH(-) ion concentration in the reaction medium as a result of water dissociation is the determining factor in the selectivity. The reaction of glucose isomerization to fructose and the further dehydration to 5-HMF are highly dependent on the ion concentration. By an increase in the pOH/pH value, these reactions were minimized to allow control of 5-HMF production. Under these conditions, the retroaldol condensation pathway was enhanced, instead of the isomerization/dehydration pathway. PMID:25704124

  7. Variability of Water Chemistry in Tundra Lakes, Petuniabukta Coast, Central Spitsbergen, Svalbard

    OpenAIRE

    Małgorzata Mazurek; Renata Paluszkiewicz; Grzegorz Rachlewicz; Zbigniew Zwoliński

    2012-01-01

    Samples of water from small tundra lakes located on raised marine terraces on the eastern coast of Petuniabukta (Ebbadalen, Central Spitsbergen) were examined to assess the changes in water chemistry that had occurred during the summer seasons of 2001–2003 and 2006. The unique environmental conditions of the study region include the predominance of sedimentary carbonate and sulphate rocks, low precipitation values, and an active permafrost layer with a maximum thickness of 1.2 m. The average ...

  8. Water chemistry characterization and component performance of a recirculating aquaculture system producing hybrid striped bass

    OpenAIRE

    Easter, Christopher

    1992-01-01

    Eight identical and independent pilot scale recirculating aquaculture production systems were populated with fingerling hybrid striped bass (Morone chrysops female x Morone saxatilis male). Three population densities were established with two replicates at 132 fishlm3 and three replicates each at 66 and 33 fishlm3. Water chemistry and water quality characteristics were monitored throughout the 228 day growth trial for all eight systems. A system component performance analys...

  9. The chemistry and activity build up in the primary systems of pressurized water nuclear plants

    International Nuclear Information System (INIS)

    After giving a background information on the present standards for the primary coolant in pressurized water nuclear reactors, the choice of particular chemical additives to the water is presented and their main properties are given; the various radioactivated products that are derived from these additives are also considered. The corrosion products transport through the whole primary circuit is then investigated. Two basically different types of processes, particularly about surface deposits, are characterized: that of suspended solids and that of soluble species, which are both carried by water. The physico-chemical data that rule the variations of solubilities for the more important elements are reviewed with details. From these data, the relation between corrosion products transport and radioactive contamination in primary circuits are examined, and this in the complex physico-chemical conditions of plant operation. Characteristic measurements, from operating power reactors, are also presented to illustrate the preceeding phenomena. Finally a chapter reviews the possible solutions against the radioactive contamination of the circuits and their surroundings: - a more adequate choice of materials, - a search for better surface treatment and application methods, - a better evaluation of the existing water conditioning, - an efficient filtration of the fluid, - the use of decontaminating processes

  10. Kinugasa Reactions in Water: From Green Chemistry to Bioorthogonal Labelling

    Directory of Open Access Journals (Sweden)

    Mariya Chigrinova

    2015-04-01

    Full Text Available The Kinugasa reaction has become an efficient method for the direct synthesis of β-lactams from substituted nitrones and copper(I acetylides. In recent years, the reaction scope has been expanded to include the use of water as the solvent, and with micelle-promoted [3+2] cycloadditions followed by rearrangement furnishing high yields of β-lactams. The high yields of stable products under aqueous conditions render the modified Kinugasa reaction amenable to metabolic labelling and bioorthogonal applications. Herein, the development of methods for use of the Kinugasa reaction in aqueous media is reviewed, with emphasis on its potential use as a bioorthogonal coupling strategy.

  11. Technical Note: Linking soil – and stream-water chemistry based on a riparian flow-concentration integration model

    OpenAIRE

    J. Seibert; T. Grabs; Köhler, S; H. Laudon; Winterdahl, M.; Bishop, K.

    2009-01-01

    The riparian zone, the last few meters of soil through which water flows before entering the stream, has been identified as a first order control on key aspects of stream water chemistry dynamics. We propose that the vertical distribution of lateral water flow across the profile of soil water chemistry in the riparian zone provides a conceptual explanation of how this control functions in catchments where matrix flow predominates. This paper presents a mathematical implementation of this conc...

  12. In-pile loop experiments in water chemistry and corrosion

    International Nuclear Information System (INIS)

    Results on the study of Zr-1% Nb alloy corrosion, in out-of and in-pile loops simulating the working conditions of the VVER-440 reactor (Soviet, PWR type), covered the time period May 1982-April 1986 were reported, as well as, results on transport and filtration of corrosion products. Methods and techniques used in the study included remote measurement of corrosion rate by polarizing resistance, out-of-pile loop at the temperature 350 deg. C, pressure 19 MPa, circulation 20 kgs/h and in-pile water loop with constant flow rate 10,000 kgs/h, pressure 16 MPa, temperature 330 deg. C and neutron flux 7x1013 n/cm2.s. It was shown that solid suspended particles with chemical composition corresponding most frequently to magnetite or nickelous ferrite, though with non-stoichiometric composition Mex2+ Fe3-x3+O4 were found. Continuous filtration of water by means of electromagnetic filter leads to a decrease of radioactivity of the outer epitactic layer only. Effect of filtration on the inner topotactic layer is negligible. The corrosion rates for the above-mentioned parameters are given

  13. Irradiation capability of Japanese materials test reactor for water chemistry experiments

    International Nuclear Information System (INIS)

    Appropriate understanding of water chemistry in the core of LWRs is essential as chemical species generated due to water radiolysis by neutron and gamma-ray irradiation govern corrosive environment of structural materials in the core and its periphery, causing material degradation such as stress corrosion cracking. Theoretical model calculation such as water radiolysis calculation gives comprehensive understanding of water chemistry at irradiation field where we cannot directly monitor. For enhancement of the technology, accuracy verification of theoretical models under wide range of irradiation conditions, i.e. dose rate, temperature etc., with well quantified in-pile measurement data is essential. Japan Atomic Energy Agency (JAEA) has decided to launch water chemistry experiments for obtaining data that applicable to model verification as well as model benchmarking, by using an in-pile loop which will be installed in the Japan Materials Testing Reactor (JMTR). In order to clarify the irradiation capability of the JMTR for water chemistry experiments, preliminary investigations by water radiolysis / ECP model calculations were performed. One of the important irradiation conditions for the experiments, i.e. dose rate by neutron and gamma-ray, can be controlled by selecting irradiation position in the core. In this preliminary study, several representative irradiation positions that cover from highest to low absorption dose rate were chosen and absorption dose rate at the irradiation positions were evaluated by MCNP calculations. As a result of the calculations, it became clear that the JMTR could provide the irradiation conditions close to the BWR. The calculated absorption dose rate at each irradiation position was provided to water radiolysis calculations. The radiolysis calculations were performed under various conditions by changing absorption dose rate, water chemistry of feeding water etc. parametrically. Qualitatively, the concentration of H2O2, O2 and H2 at

  14. Pore water chemistry of Rokle Bentonite (Czech Republic)

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. With inflowing the groundwater to Deep Geological Repository (DGR), the interaction of this water with engineering barrier materials will alter both, barrier materials and also the groundwater. One of the most important alterations represents the formation of bentonite pore water that will affect a number of important processes, e.g. corrosion of waste package materials, solubility of radionuclides, diffusion and sorption of radionuclides. The composition of bentonite pore water is influenced primarily by the composition of solid phase (bentonite), liquid phase (inflowing groundwater), the gaseous phase (partial pressure of CO2), bentonite compaction and the rate of groundwater species diffusion through bentonite. Also following processes have to be taken into account: dissolution of admixtures present in the bentonite (particularly well soluble salts, e.g. KCl, NaCl, gypsum), ion exchange process and protonation and deprotonation of surface hydroxyl groups on clay minerals. Long-term stability of mineral phases and possible mineral transformation should not be neglected as well. In the Czech Republic, DGR concept takes local bentonite into account as material for both buffer and backfill. The candidate bentonite comes from the Rokle deposit (NW Bohemia) and represents complex mixture of (Ca,Mg)-Fe-rich montmorillonite, micas, kaolinite and other mineral admixtures (mainly Ca, Mg, Fe carbonates, feldspars and iron oxides). The mineralogical and chemical characteristics were published previously. This bentonite is different in composition and properties from worldwide studied Na-bentonite (e.g. MX-80, Volclay) or Na-Ca bentonite (e.g. Febex). This fact leads to the need of investigation of Rokle bentonite in greater detail to verify its suitability as a buffer and backfill in DGR. Presented task is focused on the study of pore water evolution. Our approach for this study consists in modeling the pore water using

  15. Primary water chemistry control at units of Paks Nuclear Power Plant

    International Nuclear Information System (INIS)

    The primary water chemistry of the four identical units of Paks Nuclear Power Plant has been developed based on Western-type PWR units, taking into consideration some Soviet-Russian modifications. The political changes in 90s have also influenced the water chemistry specifications and directions. At PWR units the transition operational modes have been developed while in case of VVER units - in lack of central uniform regulation - this question has become the competence and responsibility of each individual plant. This problem has resulted in separate water chemistry developments with a considerable time delay. The needs for life-time extensions all over the World have made the development of start-up and shut-down chemistry procedures extremely important, since they considerably influence the long term and safe operation of plants. The uniformly structured limit value system, the principles applied for the system development, and the logic schemes for actions to be taken are discussed in the paper, both for normal operation and transition modes. (author)

  16. Spatial learning of the water maze: progression of brain circuits mapped with cytochrome oxidase histochemistry.

    Science.gov (United States)

    Conejo, N M; González-Pardo, H; Gonzalez-Lima, F; Arias, J L

    2010-03-01

    The progression of brain circuits involved in spatial learning tasks is still a matter of debate. In addition, the participation of individual regions at different stages of spatial learning remains a controversial issue. In order to address these questions, we used quantitative cytochrome oxidase histochemistry as a metabolic brain mapping method applied to rats (Rattus norvegicus) trained in a water maze for 1, 3 or 5 days of training. Sustained changes throughout training were found in the lateral septal nucleus and anteroventral thalamic nucleus. As compared to naïve or habituation groups, rats with 1 day of training in the spatial learning task showed involvement of the lateral mammillary nucleus, basolateral amygdala and anterodorsal thalamic nucleus. By 5 days of training, there were mean changes in the hippocampal CA3 field and the prefrontal cortex. The regions involved and their pattern of network interactions changed progressively over days of training. At 1-day there was an open serial network of pairwise correlations. At 3-days there was a more closed reciprocal network of intercorrelations. At 5-days there were three separate parallel networks. In addition, brain-behavior correlations showed that CA1 and CA3 hippocampal fields together with the parietal cortex are related to the mastery of the spatial learning task. The present study extends previous findings on the progressive contribution of neural networks to spatial learning. PMID:19969098

  17. Secondary water chemistry control practices and results of the Japanese PWR plants

    International Nuclear Information System (INIS)

    In Japan, since the start of the operation of the first PWR plant, Mihama Unit-1 in 1970, 24 PWR plants have been built by 2010, and all of them are in operation. Due to the plant-specific needs of management, and by flexibly incorporating the state-of-the-art insights into the design, the system configurations of the plants vary so many as 15 types. Meanwhile, the geographical feature of Japan makes all the Japanese PWR plants to have condensers cooled by sea water, and all the plants have a common system with a full-flow Condensate Polisher System (CPS). To prevent corrosion, continued improvements of the secondary water chemistry management has been performed like other countries, and one of the major features of the Japanese PWR plants is an enhanced provision for the condenser leakage. The water quality of SG (Steam Generator) has been significantly improved by the provision for the sea water leakage, in combination with other improvements in water chemistry management. Also in Japan, almost all of the treatments of the spent polisher resin and the wastewater are performed within the power plant sites. To facilitate the treatment of the waste water and the regeneration of the spent resins, either ammonia or ETA (Ethanol Amine) is selected as the pH adjustment agent for the secondary system water. Also at the ammonia treatment, high pH accomplishes the inhibition of the piping wall thinning and the lower iron transportation into SGs. In addition, the iron transported into the SG is removed by the chemical conditioning treatment called ASCA (Advanced Scale Conditioning Agent). This provides the effective recovery of the SG heat-transfer performance, and the improved SG support plate BEC (Broached Egg Crate) hole blockage rates. Basically in Japan, the secondary water chemistry management has been improved based on a single basic specification, for the variety of the plant configurations, with the plant-specific investigations and analyses. This paper summarizes

  18. Water chemistry control for the target/blanket region of the accelerator production of tritium

    International Nuclear Information System (INIS)

    High-energy particle interactions in the various components of the target/blanket region of the Accelerator Production of Tritium lead to heat generation and deposition. Heavy-water and light-water systems are used to cool the target/blanket system and associated equipment. Structural materials include Inconel alloy 718, aluminum-clad lead rods, aluminum tubes containing helium-3 and tritium gas, and stainless steel components. Proper coolant chemistry is required to maximize neutron production, minimize corrosion of components, and minimize activity buildup. Corrosion-related phenomena and development of coolant and moderator corrosion control for both power and defense fission reactors has been studied extensively over the past 50 years. Less is known, however, about cooling systems for accelerators where a variety of transient chemical species and spallation products may be formed. The following provides a discussion on the issues that need to be addressed for proper water chemistry control for the APT system

  19. The key to superior water chemistry at a PWR nuclear station

    International Nuclear Information System (INIS)

    This paper demonstrates how a condensate polishing unit can be successfully used to treat the feedwater for circulating-type pressurized water reactors (PWRs). Water chemistry at the Salem Generating Station, a two-unit, four-loop Westinghouse PWR located in New Jersey, is discussed. Topics considered include a plant description and the history of early operation, the role of constant surveillance, makeup water quality, the effect of freezing on gel-type anion exchange resin, a total organic carbon (TOC) survey, steam generator chemistry, steam generator inspection, condensate polisher operation, and management philosophy. The SEPREX condensate polishing process, in which the complete separation of the anion exchange resin from the cation exchange resin is achieved by flotation separation, is examined. It is concluded that the utilization of a condensate polishing process such as SEPREX provides the operating personnel at the plant with the necessary means to maintain the minimum desired level of contaminants within the steam generator

  20. Dominant processes controlling water chemistry of the Pecos River in American southwest

    Science.gov (United States)

    Yuan, Fasong; Miyamoto, Seiichi

    2005-09-01

    Here we show an analysis of river flow and water chemistry data from eleven gauging stations along the Pecos River in eastern New Mexico and western Texas, with time spanning 1959-2002. Analysis of spatial relationship between the long-term average flow and total dissolved solids (TDS) concentration allows us to illuminate four major processes controlling river chemistry, namely saline water addition, evaporative concentration with salt gain or loss, dilution with salt gain or loss, and salt storage. Of the 10 river reaches studied, six reaches exhibit the process dominated by evaporative concentration or freshwater dilution with little change in salt load. Four reaches show considerable salt gains or losses that are induced by surface-ground water interactions. This analysis suggests that the evaporative concentration and freshwater dilution are the prevailing mechanisms, but local processes (e.g., variations in hydrologic flowpath and lithologic formation) also play an important role in regulating the hydrochemistry of the Pecos River.

  1. Effects of hydrogen water chemistry on radiation field buildup in BWRs

    International Nuclear Information System (INIS)

    Boiling Water Reactors (BWRs) use high purity water as the neutron moderator and primary coolant in the production of steam. As a result of water radiolysis the coolant in the BWR under normal water chemistry (NWC) operation conditions contains approximately 200 ppb of oxidant (O2 + H2O2) in the recirculation line and several hundred ppb of oxidant in the core region. This range of the oxidant concentration increases the potential susceptibility of austenitic stainless steel and certain nickel base alloys to intergranular stress corrosion cracking (IGSCC) when other requisite factors such as stress and sensitization are present. Modification of coolant chemistry by feedwater hydrogen addition is a viable option to mitigate SCC in operating plants. Currently, there are more than 20 BWRs worldwide operating under hydrogen water chemistry (HWC) conditions. In some reactors after switching from NWC to HWC, an increase in recirculation piping dose rates has been observed, but other plants have shown very minimal or no effect. Earlier laboratory test results have shown that Co-60 deposition on stainless steel is slightly enhanced by switching from NWC to HWC, and more recent experiments have shown that the activity buildup rate is more profound under cyclic HWC/NWC conditions. Both the reactor and laboratory data will be evaluated with the aid of oxide film characterization, and a plausible mechanism of enhanced activity buildup under HWC conditions will be hypothesized. (authors). 4 figs., 4 refs

  2. Processes controlling groundwater chemistry and identification of water resource vulnerability: Yarra catchment, Victoria

    International Nuclear Information System (INIS)

    Full text: Assessment of processes controlling groundwater chemistry is essential for water resource management and identification of water resource vulnerability. The Yarra Catchment (4045 km2) extends 120 km east of Melbourne and is considered a significant area for Melbourne's water resources. This catchment is characterised by fractured rock aquifers, a high baseflow component, high, localised recharge, and diverse land use. Therefore, identification of processes controlling groundwater chemistry is important for determining areas where groundwater, and inevitably surface water, are most vulnerable to contamination. The regional groundwater flow system is affected by high, localised recharge in areas of high surface elevations. Hence, a local groundwater flow system is investigated in detail to aid regional interpretation. Processes causing spatial heterogeneity of groundwater chemistry include the extent of recharge, water-rock interaction and land use processes. At high surface elevations Na:CI = 1, and direct recharge of precipitation into sedimentary or granitic aquifers results in groundwater with lower TDS values (∼ 50 to 100 mg/L), compared to groundwater where precipitation directly recharges younger basaltic aquifers (TDS ∼ 100 to 150 mg/L). At lower surface elevations Na:CI ratios decrease, and major ion concentrations, pH and TDS are significantly higher (TDS ∼ 400 to 500 mg/L) reflecting cumulative effects of water-rock interaction and agricultural land use lower in the catchment. Groundwater samples were also analysed for stable isotopes, the 180 and 2H values (-6.2 to 5.50, and -38.1 to 32.20 VSMOW respectively) lie on the Melbourne Meteoric Water Line, indicating that groundwater has not been subjected to evaporation or high-temperature water rock interaction. Slightly lower 180 and 2H values for groundwater compared to nearby surface water indicates that recharge of colder rains occurs preferentially, both on local and more regional scales

  3. Spatiotemporal dynamics of spring and stream water chemistry in a high-mountain area

    International Nuclear Information System (INIS)

    The present study deals with the application of the self-organizing map (SOM) technique in the exploration of spatiotemporal dynamics of spring and stream water samples collected in the Chocholowski Stream Basin located in the Tatra Mountains (Poland). The SOM-based classification helped to uncover relationships between physical and chemical parameters of water samples and factors determining the quality of water in the studied high-mountain area. In the upper part of the Chocholowski Stream Basin, located on the top of the crystalline core of the Tatras, concentrations of the majority of ionic substances were the lowest due to limited leaching. Significantly higher concentration of ionic substances was detected in spring and stream samples draining sedimentary rocks. The influence of karst-type springs on the quality of stream water was also demonstrated. - Highlights: → We use SOM approach to explore physiochemical data for mountain waters. → Geologic structure and hydrological events impact water chemistry. → Limited leaching, typical of crystalline core, reflects in low water mineralization. → Sedimentary rocks are susceptible for leaching. → Eutrophication has not been shown to be a threat in the Chocholowska Valley. - Spatiotemporal dynamics of spring and stream water chemistry in unique high-mountain area was evaluated by the self-organizing map technique.

  4. Carbon key-properties for microcystin adsorption in drinking water treatment: structure or surface chemistry?

    OpenAIRE

    Júlio, Maria de Fátima de Jesus Leal

    2011-01-01

    The carbon key-properties (structure and surface chemistry) for microcystin-LR (MC-LR) adsorption onto activated carbon were investigated. Waters with an inorganic background matrix approaching that of the soft natural water (2.5 mM ionic strength) were used. Also, model waters with controlled ionic make-up and NOM surrogate with similar size of MC-LR (tannic acid - TA) with MC-LR extracts were tested with activated carbon NORIT 0.8 SUPRA. For this AC, two particle sizes, 125-180 μm and 63-90...

  5. Study on the application of enriched boric acid in PWR primary water chemistry

    International Nuclear Information System (INIS)

    Natural boric acid is used in PWRs as chemical shim to control excess reactivity. After the implement of long-cycle fuel management, boron concentration will be increased, and water chemistry controlling will become more difficult. The paper analyzes the feasibility of enriched boric acid (EBA) used in the primary system of the nuclear power plants (NPPs) and the influence to correlative water chemical treatment systems. The study shows the EBA can reduce the corrosion rate of the primary system materials and radiation field, improve the economy of the in-service NPPs. It will be important to improve the technology of NPP primary water treatment. (authors)

  6. Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2005-01-01

    Full Text Available A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM ECHAM4.L39(DLR/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run

  7. Proposal for the modernization of CDTN's Air-Water CCFL experimental test circuit

    Energy Technology Data Exchange (ETDEWEB)

    Pessoa, Marcio Araujo; Mesquita, Amir Zacarias; Navarro, Moyses A.; Santos, Andre A. Campagnole dos, E-mail: marcioaraujopessoa@gmail.com, E-mail: amir@cdtn.br, E-mail: moysesnavarro@yahoo.com.br, E-mail: aacs@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEM-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    The Counter Current Flow Limitation (CCFL) phenomenon, specifically the control that the gas exerts in a liquid flow in the opposite direction, is of real importance in the study of design and operation of various industrial sectors, particularly the nuclear industry. In nuclear engineering, such a phenomenon can occur in a loss of coolant accident (LOCA) of a Pressurized Water Reactor (PWR) when there is the need to re-flood the reactor core during an emergency cooling process. The CCFL phenomenon is being investigated at the Nuclear Technology Development Center (CDTN) thermo-hydraulics laboratory in order to better understand the flow and its limitations and thereby contribute to the improvement of its modeling for analysis of severe accidents. For this, a series of experiments were performed in CDTN in a reduced scale acrylic test section of the 'hot leg' of a PWR. In these tests, the countercurrent flow was established through the water injection by the upper end of the inclined pipe and the air addition at the end opposite to the entry of liquid flow. With the gradual increase of the air flow for predetermined water levels, the onset of the limitation of flow to the full blockage was determined. After full blockage, a gradual reduction of air flow was performed to evaluate the deflooding of the hot leg. The trials also evaluated CCFL behavior for various lengths of the horizontal section, the inclined duct slope influence and the dependence of the pipe's diameter. The infrastructure for CCFL analysis was built 14 years ago and has not been updated since. This paper describes the updates that are being performed to the existing setup. Hydraulic circuit and instrumentation upgrades and the implementation of modern control systems will allow new data to be collected and a new range of experiments to be performed with lower uncertainty. It is intended that the new data be used to validate CFD models that are also being developed by the research

  8. Proposal for the modernization of CDTN's Air-Water CCFL experimental test circuit

    International Nuclear Information System (INIS)

    The Counter Current Flow Limitation (CCFL) phenomenon, specifically the control that the gas exerts in a liquid flow in the opposite direction, is of real importance in the study of design and operation of various industrial sectors, particularly the nuclear industry. In nuclear engineering, such a phenomenon can occur in a loss of coolant accident (LOCA) of a Pressurized Water Reactor (PWR) when there is the need to re-flood the reactor core during an emergency cooling process. The CCFL phenomenon is being investigated at the Nuclear Technology Development Center (CDTN) thermo-hydraulics laboratory in order to better understand the flow and its limitations and thereby contribute to the improvement of its modeling for analysis of severe accidents. For this, a series of experiments were performed in CDTN in a reduced scale acrylic test section of the 'hot leg' of a PWR. In these tests, the countercurrent flow was established through the water injection by the upper end of the inclined pipe and the air addition at the end opposite to the entry of liquid flow. With the gradual increase of the air flow for predetermined water levels, the onset of the limitation of flow to the full blockage was determined. After full blockage, a gradual reduction of air flow was performed to evaluate the deflooding of the hot leg. The trials also evaluated CCFL behavior for various lengths of the horizontal section, the inclined duct slope influence and the dependence of the pipe's diameter. The infrastructure for CCFL analysis was built 14 years ago and has not been updated since. This paper describes the updates that are being performed to the existing setup. Hydraulic circuit and instrumentation upgrades and the implementation of modern control systems will allow new data to be collected and a new range of experiments to be performed with lower uncertainty. It is intended that the new data be used to validate CFD models that are also being developed by the research

  9. Study of water radiolysis in relation with the primary cooling circuit of pressurized water reactors; Etude sur la radiolyse de l`eau en relation avec le circuit primaire de refroidissement des reacteurs nucleaires a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Pastina, B

    1997-07-01

    This memorandum shows a fundamental study on the water radiolysis in relation with the cooling primary circuit of PWR type reactors. The water of the primary circuit contains boric acid a soluble neutronic poison and also hydrogen that has for role to inhibit the water decomposition under radiation effect. In the aim to better understand the mechanism of dissolved hydrogen action and to evaluate the impact of several parameters on this mechanism, aqueous solutions with boric acid and hydrogen have been irradiated in a experimental nuclear reactor, at 30, 100 and 200 Celsius degrees. It has been found that, with hydrogen, the water decomposition under irradiation is a threshold phenomenon in function of the ratio between the radiation flux `1` B(n, )`7 Li and the gamma flux. When this ratio become too high, the number of radicals is not sufficient to participate at the chain reaction, and then water is decomposed in O{sub 2} and H{sub 2}O{sub 2} in a irreversible way. The temperature has a beneficial part on this mechanism. The iron ion and the copper ion favour the water decomposition. (N.C.). 83 refs.

  10. Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

    Directory of Open Access Journals (Sweden)

    M. Mena

    2005-06-01

    Full Text Available Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period. No anthropogenic pollution from Volatile Organic Compounds (VOCs was observed. An overview of the soil radon behaviour as a function of the volcanic activity in the period 1994-2002 is also discussed.

  11. Effects of reduced nitrogen and sulphur deposition on the water chemistry of moorland pools

    International Nuclear Information System (INIS)

    To assess changes as a result of reduced acidifying deposition, water chemistry data from 68 Dutch moorland pools were collected during the periods 1983-1984 and 2000-2006. Partial recovery was observed: nitrate- and ammonium-N, sulphur and aluminium concentrations decreased, while pH and alkalinity increased. Calcium and magnesium concentrations decreased. These trends were supported by long term monitoring data (1978-2006) of four pools. Increased pH correlated with increases in ortho-phosphate and turbidity, the latter due to stronger coloration by organic acids. Increased ortho-phosphate and turbidity are probably the result of stronger decomposition of organic sediments due to decreased acidification and may hamper full recovery of moorland pool communities. In addition to meeting emission targets for NOx, NHx and SOx, restoration measures are still required to facilitate and accelerate recovery of acidified moorland pools. - Partial recovery of moorland pool water chemistry after reduction of nitrogen and sulphur deposition.

  12. Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

    OpenAIRE

    Mena, M.; G. Cisniega; Lopez, B.; M. A. Armienta; Valdés, C; Peña, P; N. Segovia

    2005-01-01

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration d...

  13. Water chemistry and soil radon survey at the Poas volcano (Costa Rica)

    OpenAIRE

    Seidel, J.L.; M. Monnin; Fernandez, E.; J. Barquero; N. Segovia

    2005-01-01

    Radon-in-soil monitoring at the Poas volcano (Costa Rica) has been performed together with water chemistry from the hot crater lake since 1981 and 1983 respectively. The results are discussed as a function of the eruptive evolution of the volcano over a 13 years period (1981-1994). It is shown that no definitely clear precursory radon signals have been recorded. On the contrary, ionic species concentrations are likely to be considered good precursors, together with the tem...

  14. Responses in tropospheric chemistry to changes in UV fluxes, temperatures and water vapour densities

    OpenAIRE

    Fuglestvedt, Jan S.; Jonson, J.E.; WANG, WEI-CHYUNG; Isaksen, Ivar S.A.

    1994-01-01

    A two-dimensional chemistry/transport model of the global troposphere is used to study the chemical response to i) increased UV-radiation from stratospheric ozone depletion and ii) increased temperatures and water vapour densities that follow from in-creased levels of greenhouse gases. Increased UV radiation increases the photolysis rates for several tropospheric gases, in particular ozone. This leads to enhanced levels of odd hydrogen and reduced concentrations of tropospheric ozone. Increas...

  15. Effects of iron on arsenic speciation and redox chemistry in acid mine water

    Science.gov (United States)

    Bednar, A.J.; Garbarino, J.R.; Ranville, J.F.; Wildeman, T.R.

    2005-01-01

    Concern about arsenic is increasing throughout the world, including areas of the United States. Elevated levels of arsenic above current drinking-water regulations in ground and surface water can be the result of purely natural phenomena, but often are due to anthropogenic activities, such as mining and agriculture. The current study correlates arsenic speciation in acid mine drainage and mining-influenced water with the important water-chemistry properties Eh, pH, and iron(III) concentration. The results show that arsenic speciation is generally in equilibrium with iron chemistry in low pH AMD, which is often not the case in other natural-water matrices. High pH mine waters and groundwater do not always hold to the redox predictions as well as low pH AMD samples. The oxidation and precipitation of oxyhydroxides deplete iron from some systems, and also affect arsenite and arsenate concentrations through sorption processes. ?? 2004 Elsevier B.V. All rights reserved.

  16. Stream water chemistry after two forest fertilizations with Skog Vital in central Sweden

    International Nuclear Information System (INIS)

    A study was made of the impact of forest fertilization (non-nitrogenous mix) on the water chemistry of two streams, which drain catchment areas in east Haerjedalen in Sweden. In summer 1990, part of one of the catchment areas was fertilized by tractor at a dose of 0.6 tonnes per hectare, and part of the other by helicopter at a dose of 0.5 tonnes per hectare. The fertilizer contained base cations, sulphur, phosphorus, zinc and boron. Water samples were taken at a water-sampling station upstream of the treated area and at a water-sampling station downstream of the treated area. A total of 30 samples were made and the water was analysed for pH, alkalinity, nitrogen, phosphorus, base cations, aluminium and sulphate. Discharge was both measured and simulated, the latter using a runoff model. An estimate was made of the additional leaching resulting from fertilization. 13 refs, 12 figs, 6 tabs

  17. Electrochemical study of galvanic corrosion inhibitors in water-based and ethylene glycol-based heat transfer circuits

    International Nuclear Information System (INIS)

    This research thesis reports the search for and the efficiency assessment of mixes of inhibitors for coolant circuits of motor cars. After a discussion of the general properties of water-alcohol solvents (chemical properties, acid-base equilibriums) and of parameters affecting corrosion in coolant circuits, the author proposes an overview of the main inhibitors which are used to protect these circuits against corrosion, and discusses their action mechanism and efficiency. The different methods used to study the corrosion of these circuits are described, and the advantages and drawbacks of test methods are commented. The second part proposes a synthesis of the different corrosion electromechanical mechanisms which may occur with respect to the used metallic materials and to possible galvanic couplings. The next part describes the experimental installations. The last part focuses on the different protections obtained with the different used inhibitor class in terms of results obtained by gravimetric tests and visual examination of samples, current-voltage curves in hydrodynamic regime, and galvanic corrosion tests performed in laboratory or in situ in motor cars

  18. Hydrogeochemical processes controlling water and dissolved gas chemistry at the Accesa sinkhole (southern Tuscany, central Italy

    Directory of Open Access Journals (Sweden)

    Franco Tassi

    2014-05-01

    Full Text Available The 38.5 m deep Lake Accesa is a sinkhole located in southern Tuscany (Italy that shows a peculiar water composition, being characterized by relatively high total dissolved solids (TDS values (2 g L-1 and a Ca(Mg-SO4 geochemical facies. The presence of significant amounts of extra-atmospheric gases (CO2 and CH4, which increase their concentrations with depth, is also recognized. These chemical features, mimicking those commonly shown by volcanic lakes fed by hydrothermal-magmatic reservoirs, are consistent with those of mineral springs emerging in the study area whose chemistry is produced by the interaction of meteoric-derived waters with Mesozoic carbonates and Triassic evaporites. Although the lake has a pronounced thermocline, water chemistry does not show significant changes along the vertical profile. Lake water balance calculations demonstrate that Lake Accesa has >90% of its water supply from sublacustrine springs whose subterranean pathways are controlled by the local structural assessment that likely determined the sinking event, the resulting funnel-shape being then filled by the Accesa waters. Such a huge water inflow from the lake bottom (~9·106 m3 yr-1 feeds the lake effluent (Bruna River and promotes the formation of water currents, which are able to prevent the establishment of a vertical density gradient. Consequently, a continuous mixing along the whole vertical water column is established. Changes of the drainage system by the deep-originated waters in the nearby former mining district have strongly affected the outflow rates of the local mineral springs; thus, future intervention associated with the ongoing remediation activities should carefully be evaluated to preserve the peculiar chemical features of Lake Accesa.

  19. Surface analytical and electrochemical characterization of oxide films formed on Incoloy-800 and carbon steel in simulated secondary water chemistry conditions of PHWRs

    International Nuclear Information System (INIS)

    The water chemistry in the Steam Generator (SG) Circuits of Indian Pressurized Heavy Water Reactors (PHWRs) is controlled by the all volatile treatment (AVT) procedure, wherein volatile amines are used to maintain the alkaline pH required for minimizing the corrosion of the structural materials. Earlier, Monel and morpholine were used as the Steam Generator material and the alkalizing agent respectively. However, currently they are replaced by Incoloy-800 and Ethanolamine (ETA). ETA was chosen because of its beneficial effects due to low pKb and Kd values, loading behaviour on condensate polishing unit (CPU) and also on cost comparison with other amines. Since we have Incoloy-800 on the tube side and Carbon steel(CS) on the shell side in the SG circuits, efforts were taken to study the nature of the oxide films formed on these surfaces and to evaluate the corrosion resistance and electrochemical properties of the same, under simulated secondary water chemistry conditions of PHWRs containing different dissolved oxygen (DO) concentration. In this context, experiments were carried out by exposing finely polished CS and Incoloy -800 coupons to ETA based medium in the presence and absence of Hydrazine (pH: 9.2) at 240 oC under two different DO conditions (< 10 ppb and 200 ppb) for 24 hours. Oxide films formed under these conditions were characterized using SEM, Raman spectroscopy, electrochemical impedance, polarization and Mott-Schottky techniques. Further, studies at a controlled DO level ( < 10 ppb) were carried out for different time durations viz., 7- and 30- days. The composition, surface morphology, oxide thickness, resistance, type of semi-conductivity and defect density of the oxide films were evaluated and correlated with the DO levels and discussed elaborately in this paper. (author)

  20. Surface analytical and electrochemical characterization of oxide film layers formed on Incoloy 800 and carbon steel in simulated secondary water chemistry conditions of PHWRs

    Energy Technology Data Exchange (ETDEWEB)

    Rangarajan, Srinivasan; Chandran, Sinu; Balaji, Vadivelu; Narasimhan, Sevilmedu V. [BARC Facilities, Kalpakkam, Tamil Nadu (India). Water and Steam Chemistry Div.

    2011-06-15

    The water chemistry in the steam generator (SG) circuits of Indian pressurized heavy water reactors (PHWRs) is controlled by the all-volatile treatment (AVT) procedure, wherein volatile amines are used to maintain the alkaline pH required for minimizing the corrosion of the structural materials. Earlier, Monel and morpholine were used as the steam generator material and the alkalizing agent respectively. However, currently they have been replaced by Incoloy 800 and ethanolamine (ETA). ETA was chosen because of its beneficial effects due to low pKb and Kd values, loading behavior on the condensate polishing unit (CPU), and also based on cost comparison with other amines. Since we have Incoloy 800 on the tube side and carbon steel (CS) on the shell side in the SG circuits, efforts were taken to study the nature of the oxide films formed on these surfaces and to evaluate the corrosion resistance and electrochemical properties of the same under simulated secondary water chemistry conditions of PHWRs containing different dissolved oxygen (DO) concentrations. In this context, experiments were carried out by exposing finely polished CS and Incoloy 800 coupons to ETA-based medium in the presence and absence of hydrazine (pH: 9.2) at 240 C under two different DO conditions (< 10 {mu}g . L{sup -1} and 300 {mu}g . L{sup -1}) for 24 hours. Oxide films formed under these conditions were characterized using scanning electron microscopy, Raman spectroscopy, electrochemical impedance, polarization and Mott-Schottky techniques. Further, studies at a controlled DO level (< 10 {mu}g . L{sup -1}) were carried out for different time durations, viz., 7 and 30 days. The composition, surface morphology, oxide thickness, resistance, type of semiconductivity and defect density of the oxide films were evaluated and correlated with the DO levels and are discussed elaborately in this paper. (orig.)

  1. Surface analytical and electrochemical characterization of oxide film layers formed on Incoloy 800 and carbon steel in simulated secondary water chemistry conditions of PHWRs

    International Nuclear Information System (INIS)

    The water chemistry in the steam generator (SG) circuits of Indian pressurized heavy water reactors (PHWRs) is controlled by the all-volatile treatment (AVT) procedure, wherein volatile amines are used to maintain the alkaline pH required for minimizing the corrosion of the structural materials. Earlier, Monel and morpholine were used as the steam generator material and the alkalizing agent respectively. However, currently they have been replaced by Incoloy 800 and ethanolamine (ETA). ETA was chosen because of its beneficial effects due to low pKb and Kd values, loading behavior on the condensate polishing unit (CPU), and also based on cost comparison with other amines. Since we have Incoloy 800 on the tube side and carbon steel (CS) on the shell side in the SG circuits, efforts were taken to study the nature of the oxide films formed on these surfaces and to evaluate the corrosion resistance and electrochemical properties of the same under simulated secondary water chemistry conditions of PHWRs containing different dissolved oxygen (DO) concentrations. In this context, experiments were carried out by exposing finely polished CS and Incoloy 800 coupons to ETA-based medium in the presence and absence of hydrazine (pH: 9.2) at 240 C under two different DO conditions (-1 and 300 μg . L-1) for 24 hours. Oxide films formed under these conditions were characterized using scanning electron microscopy, Raman spectroscopy, electrochemical impedance, polarization and Mott-Schottky techniques. Further, studies at a controlled DO level (-1) were carried out for different time durations, viz., 7 and 30 days. The composition, surface morphology, oxide thickness, resistance, type of semiconductivity and defect density of the oxide films were evaluated and correlated with the DO levels and are discussed elaborately in this paper. (orig.)

  2. Introduction of Mass Spectrometry in an First-Semester General Chemistry Laboratory Course: Quantification of Mtbe or Dmso in Water

    Science.gov (United States)

    Solow, Mike

    2004-01-01

    Quantification of a contaminant in water provides the first-year general chemistry students with a tangible application of mass spectrometry. The relevance of chemistry to assessing and solving environmental problems is highlighted for students when they perform mass spectroscopy experiments.

  3. Supercritical water in analytical chemistry: A green solvent to manipulate fused-silica capillaries for separation methods

    Czech Academy of Sciences Publication Activity Database

    Karásek, Pavel; Horká, Marie; Šlais, Karel; Planeta, Josef; Roth, Michal

    Nottingham, 2013. O86. [International Conference on Green and Sustainable Chemistry /6./. 04.08.2013-07.08.2013, Nottingham] R&D Projects: GA ČR(CZ) GAP106/12/0522; GA MV VG20102015023 Institutional support: RVO:68081715 Keywords : supercritical water * fused silica capillary * analytical separation methods Subject RIV: CB - Analytical Chemistry , Separation

  4. Optimisation of water chemistry to ensure reliable water reactor fuel performance at high burnup and in ageing plant (FUWAC): an International Atomic Energy Agency coordinated research project

    International Nuclear Information System (INIS)

    The IAEA project 'Optimisation of Water Chemistry to ensure Reliable Water Reactor Fuel Performance at High Burnup and in Aging Plant' (FUWAC) was initiated with the objectives of monitoring, maintaining and optimising water chemistry regimes in primary circuits of water cooled power reactors, taking into account high burnup operation, mixed cores and plant aging, including following issues and remedies. This report provides some highlights of the work undertaken by the project participants. Clad oxidation studies have been undertaken and include operational data from the South Ukraine WWER where no corrosion problems have been seen on either Westinghouse ZIRLO™ or Russian alloy E110 fuel cladding. Work on the Russian alloy E110 showed that potassium in the coolant is preferable to lithium for mitigating fuel cladding oxidation. Studies on crud behaviour in PWR have shown a dependence on crud thickness and pHT. The nature and mechanisms for boron deposition in fuel cladding cruds have been investigated which is the root cause of crud induced power shifts (CIPS). Operational experience at French PWRs shows no difference in the CIPS behaviour between units with Alloy 600 or 690 steam generators, whilst Korean experience provides information on the Ni/Fe ratio on fuel cladding crud and the occurrence of CIPS. Coolant additions have been studied, for example in BWR units using zinc addition, crud is more tenacious. Zinc is also added to PWR units, mainly for dose rate control and in some cases for PWSCC mitigation of Alloy 600. At low levels there has been no clear evidence of any effect of zinc on CIPS, but there is a benefit on fuel oxidation. It is suggested that zinc addition should be considered where there is SG replacement or fuel core management modification. One possibility for the elimination of fuel crud is decontamination. Such an operation is time consuming, expensive, includes several risks of corrosion and induces a large quantity of

  5. Wildfires and water chemistry: effect of metals associated with wood ash.

    Science.gov (United States)

    Cerrato, José M; Blake, Johanna M; Hirani, Chris; Clark, Alexander L; Ali, Abdul-Mehdi S; Artyushkova, Kateryna; Peterson, Eric; Bixby, Rebecca J

    2016-08-10

    The reactivity of metals associated with ash from wood collected from the Valles Caldera National Preserve, Jemez Mountains, New Mexico, was assessed through a series of laboratory experiments. Microscopy, spectroscopy, diffraction, and aqueous chemistry measurements were integrated to determine the chemical composition of wood ash and its effect on water chemistry. Climate change has caused dramatic impacts and stresses that have resulted in large-scale increases in wildfire activity in semi-arid areas of the world. Metals and other constituents associated with wildfire ash can be transported by storm event runoff and negatively affect the water quality in streams and rivers. Differences among ash from six tree species based on total concentrations of metals such as Ca, Al, Mg, Fe, and Mn were identified using non-metric multidimensional analysis. Metal-bearing carbonate and oxide phases were quantified by X-ray diffraction analyses and X-ray spectroscopy analyses. These metal-bearing carbonate phases were readily dissolved in the first 30 minutes of reaction with 18 MΩ water and 10 mM HCO3(-) in laboratory batch experiments which resulted in the release of metals and carbonates in the ash, causing water alkalinity to increase. However, metal concentrations decreased over the course of the experiment, suggesting that metals re-adsorb to ash. Our results suggest that the dissolution of metal-bearing carbonate and oxide phases in ash and metal re-adsorption to ash are relevant processes affecting water chemistry after wildfire events. These results have important implications to better understand the impact of wildfire events on water quality. PMID:27457586

  6. Activity transport models for PWR primary circuits

    International Nuclear Information System (INIS)

    The corrosion products activated in the primary circuit form a major source of occupational radiation dose in the PWR reactors. Transport of corrosion activity is a complex process including chemistry, reactor physics, thermodynamics and hydrodynamics. All the mechanisms involved are not known and there is no comprehensive theory for the process, so experimental test loops and plant data are very important in research efforts. Several activity transport modelling attempts have been made to improve the water chemistry control and to minimise corrosion in PWR's. In this research report some of these models are reviewed with special emphasis on models designed for Soviet VVER type reactors. (51 refs., 16 figs., 4 tabs.)

  7. Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Bruce C [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Colson, Steven D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Laufer, Allan H [US Department of Energy Office of Science Office of Basic Energy Sciences; Ray, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2003-06-10

    On September 26–28, 2002, a workshop entitled “Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry” was held to assess new research opportunities in electron-driven processes and radical chemistry in aqueous systems. Of particular interest was the unique and complex role that the structure of water plays in influencing these processes. Novel experimental and theoretical approaches to solving long-standing problems in the field were explored. A broad selection of participants from universities and the national laboratories contributed to the workshop, which included scientific and technical presentations and parallel sessions for discussions and report writing.

  8. Hydrogen chloride heterogeneous chemistry on frozen water particles in subsonic aircraft plume. Laboratory studies and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Persiantseva, N.V.; Popovitcheva, O.B.; Rakhimova, T.V. [Moscow State Univ. (Russian Federation)

    1997-12-31

    Heterogeneous chemistry of HCl, as a main reservoir of chlorine content gases, has been considered after plume cooling and ice particle formation. The HCl, HNO{sub 3}, N{sub 2}O{sub 5} uptake efficiencies by frozen water were obtained in a Knudsen-cell flow reactor at the subsonic cruise conditions. The formation of ice particles in the plume of subsonic aircraft is simulated to describe the kinetics of gaseous HCl loss due to heterogeneous processes. It is shown that the HCl uptake by frozen water particles may play an important role in the gaseous HCl depletion in the aircraft plume. (author) 14 refs.

  9. Steam water cycle chemistry of liquid metal cooled innovative nuclear power reactors

    International Nuclear Information System (INIS)

    selection of chemistry controls is vital for NPPs with liquid metal cooled reactors. This paper highlights principles and approaches to chemistry controls in steam/water cycles of future NPPs with innovative liquid metal cooled reactors. The recommendations on how to arrange chemistry controls in steam/water cycles of future NPPs with innovative liquid metal cooled reactors are based taking into account: - the experience with operation of fossil power industry; - secondary side water chemistry of lead-bismuth eutectics cooled nuclear reactors at submarines; - steam/water cycles of NPPs with sodium cooled fast breeders BN-350 and BN-600; - secondary water chemistry at conventional NPPs with WER, RBMK and some other reactors. (authors)

  10. Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

    International Nuclear Information System (INIS)

    The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific odometer cells were used allowing 'flushing' the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96. (authors)

  11. Investigating the pore-water chemistry effects on the volume change behaviour of Boom clay

    Science.gov (United States)

    Deng, Y. F.; Cui, Y. J.; Tang, A. M.; Nguyen, X. P.; Li, X. L.; Van Geet, M.

    The Essen site has been chosen as an alternative site for nuclear waste disposal in Belgium. The soil formation involved at this site is the same as at Mol site: Boom clay. However, owing to its geographical situation closer to the sea, Boom clay at Essen presents a pore water salinity 4-5 times higher than Boom clay at Mol. This study aims at studying the effects of pore water salinity on the hydro-mechanical behaviour of Boom clay. Specific oedometer cells were used allowing “flushing” the pore water in soil specimen by synthetic pore water or distilled water. The synthetic pore water used was prepared with the chemistry as that for the site water: 5.037 g/L for core Ess83 and 5.578 g/L for core Ess96. Mechanical loading was then carried out on the soil specimen after flushing. The results show that water salinity effect on the liquid limit is negligible. The saturation or pore water replacement under the in situ effective stress of 2.4 MPa does not induce significant volume change. For Ess83, hydro-mechanical behaviour was found to be slightly influenced by the water salinity; on the contrary, no obvious effect was identified on the hydro-mechanical behaviour of Ess96. This can be attributed to the higher smectite content in Ess83 than in Ess96.

  12. Evolution of water chemistry during Marcellus Shale gas development: A case study in West Virginia.

    Science.gov (United States)

    Ziemkiewicz, Paul F; Thomas He, Y

    2015-09-01

    Hydraulic fracturing (HF) has been used with horizontal drilling to extract gas and natural gas liquids from source rock such as the Marcellus Shale in the Appalachian Basin. Horizontal drilling and HF generates large volumes of waste water known as flowback. While inorganic ion chemistry has been well characterized, and the general increase in concentration through the flowback is widely recognized, the literature contains little information relative to organic compounds and radionuclides. This study examined the chemical evolution of liquid process and waste streams (including makeup water, HF fluids, and flowback) in four Marcellus Shale gas well sites in north central West Virginia. Concentrations of organic and inorganic constituents and radioactive isotopes were measured to determine changes in waste water chemistry during shale gas development. We found that additives used in fracturing fluid may contribute to some of the constituents (e.g., Fe) found in flowback, but they appear to play a minor role. Time sequence samples collected during flowback indicated increasing concentrations of organic, inorganic and radioactive constituents. Nearly all constituents were found in much higher concentrations in flowback water than in injected HF fluids suggesting that the bulk of constituents originate in the Marcellus Shale formation rather than in the formulation of the injected HF fluids. Liquid wastes such as flowback and produced water, are largely recycled for subsequent fracturing operations. These practices limit environmental exposure to flowback. PMID:25957035

  13. Hydrogen water chemistry for BWRs: A status report on the EPRI development program

    International Nuclear Information System (INIS)

    Many boiling water reactors (BWRs) have experienced extensive intergranular stress corrosion cracking (IGSCC) in their austenitic stainless steel reactor coolant system piping, resulting in serious adverse impacts on plant capacity factors, operating and maintenance costs, and personnel radiation exposures. A major research program to provide remedies for BWR pipe cracking was funded by Electric Power Research Institute, General Electric, and the BWR Owners Group for IGSCC Research between 1979 and 1988. Results from this program show that the likelihood of IGSCC depends on reactor water chemistry (particularly on the concentrations of ionic impurities and oxidizing radiolysis products) as well as on material condition and the level of tensile stress. Tests have demonstrated that the concentration of oxidizing radiolysis products in the recirculating reactor water of a BWR can be reduced substantially by injecting hydrogen into the feedwater. Recent plant data show that the use of hydrogen injection can reduce the rate of IGSCC to insignificant levels if the concentration of ionic impurities in the reactor water is kept sufficiently low. This approach to the control of BWR pipe cracking is called hydrogen water chemistry (HWC). This paper presents a review of the results of EPRI's HWC development program from 1980 to the present. In addition, plans for additional work to investigate the feasibility of adapting HWC to protect the BWR vessel and major internal components from potential stress corrosion cracking problems are summarized

  14. Complexes and clusters of water relevant to atmospheric chemistry: H2O complexes with oxidants.

    Science.gov (United States)

    Sennikov, Petr G; Ignatov, Stanislav K; Schrems, Otto

    2005-03-01

    Experimental observations and data from quantum chemical calculations on complexes between water molecules and small, oxygen-containing inorganic species that play an important role as oxidants in the atmosphere (O(1D), O(3P), O2(X3sigmag), O2(b1sigmag+), O3, HO, HOO, HOOO, and H2O2) are reviewed, with emphasis on their structure, hydrogen bonding, interaction energies, thermodynamic parameters, and infrared spectra. In recent years, weakly bound complexes containing water have increasingly attracted scientific attention. Water in all its phases is a major player in the absorption of solar and terrestrial radiation. Thus, complexes between water and other atmospheric species may have a perceivable influence on the radiative balance and contribute to the greenhouse effect, even though their concentrations are low. In addition, they can play an important role in the chemistry of the Earth's atmosphere, particularly in the oxidation of trace gases. Apart from gas-phase complexes, the interactions of oxidants with ice surfaces have also received considerable advertency lately due to their importance in the chemistry of snow, ice clouds, and ice surfaces (e.g., ice shields in polar regions). In paleoclimate--respectively paleoenvironmental--studies, it is essential to understand the transfer processes from the atmosphere to the ice surface. Consequently, special attention is being paid here to the intercomparison of the properties of binary complexes and the complexes and clusters of more complicated compositions, including oxidants adsorbed on ice surfaces, where ice is considered a kind of large water cluster. Various facts concerning the chemistry of the Earth's atmosphere (concentration profiles and possible influence on radical reactions in the atmosphere) are discussed. PMID:15799459

  15. Relationships between precipitation and surface water chemistry in three Carolina bays

    International Nuclear Information System (INIS)

    Carolina Bays are shallow freshwater wetlands, the only naturally occurring lentic systems on the southeastern coastal plain. Bays are breeding sites for many amphibian species, but data on precipitation/surface water relationships and long-term chemical trends are lacking. Such data are essential to interpret major fluctuations in amphibian populations. Surface water and bulk precipitation were sampled bi-weekly for over two years at three bays along a 25 km transect on the Savannah River Site in South Carolina. Precipitation chemistry was similar at all sites; average pH was 4.56, and the major ions were H+ (30.8 % of total), and SO4 (50.3% of total). H+ was positively correlated with SO4, suggesting the importance of anthropogenic acids to precipitation chemistry. All three bays, Rainbow Bay (RB), Thunder Bay (TB), and Ellenton Bay (EB), contained soft (specific conductivity 5--90 microS/cm), acidic water (pH 4.0--5.9) with DOM from 4--40 mg/L. The major cation for RB, TB, and EB, respectively, was: Mg (30.8 % of total); Na (27% of total); and Ca (34.2% of total). DOM was the major anion for all bays, and SO4 represented 13 to 28 % of total anions. H+ was not correlated to DOM or SO, in RB; H+ was positively correlated to DOM and SO4 in TB, and negatively correlated to DOM and SO4 in EB. Different biogeochemical processes probably control pH and other chemical variables in each bay. While surface water H+ was not directly correlated with precipitation H+, NO3, or SO4, precipitation and shallow groundwater are dominant water sources for these bays. Atmospheric inputs of anthropogenic acids and other chemicals are important factors influencing bay chemistry

  16. Corrosion product balances for the Ringhals PWR plants based on extensive fuel crud and water chemistry measurements

    International Nuclear Information System (INIS)

    The corrosion product balance in a PWR plant is of great importance for the fuel performance as well as for the radiation field buildup. This balance is of special concern in connection to steam generator replacement (SGR) and power uprate projects. The Ringhals PWRs are all of Westinghouse design. Two of the plants have performed Steam Generator Replacement (SGR) to I-690 SG tubes and such a replacement is being planned in the third and last unit in 2011. Two of the units are in different phases of power uprate projects. The plants are all on 10-14-months cycles operating with medium to high fuel duty. Water chemistry is controlled by a pH300 in the range ∼7.2 to 7.4 from beginning of cycle to end of cycle (BOC-EOC) in the units with new SGs while kept at a coordinated pH of 7.2 in the one still using I-600. The maximum Li content has recently been increased to about 4.5 to 5 ppm in all units. In order to be able to improve the assessment of corrosion product balances in the plants, comprehensive fuel crud measurements were performed in 2007. Improved integrated reactor water sampling techniques have also been introduced in order to make accurate mass balances possible. The corrosion products covered in the study are the main constituents, Ni, Fe and Cr in the primary circuit Inconel and stainless steel, together with Co. The activated corrosion products, Co-58, Co-60, Cr-51, Fe-59 and Mn-54, are all mainly produced through neutron irradiation of the covered corrosion products. The main results of the corrosion product balances are presented. Observed differences between the plants, indicating significant impact of pH control and SG tube materials, are presented and discussed. The importance of accurate sampling techniques is especially addressed in this paper. (author)

  17. INLAND DISSOLVED SALT CHEMISTRY: STATISTICAL EVALUATION OF BIVARIATE AND TERNARY DIAGRAM MODELS FOR SURFACE AND SUBSURFACE WATERS

    Science.gov (United States)

    We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models e...

  18. Developments of water chemistry management in the Fugen Nuclear Power Station

    International Nuclear Information System (INIS)

    With regards to the chemistry control of reactor coolant, a water chemistry control technique, which mainly aims to confirm and maintain the integrity of reactor construction material including fuel clad and aims to lower the exposure dose, has been adopted at Fugen NPS just like other LWRs. Fugen applied hydrogen injection from 1985 for the first time in Japan, until its operational termination, as a countermeasure against stress corrosion cracking with equipment and piping of reactor coolant system. Additionally, Fugen implemented full system chemical decontamination for the reactor coolant system in 1989 as a measure to reduce the dose of radiation to which workers are exposed. However, re-contamination was recognized and zinc injection was introduced as a technology to suppress the re-contamination. Zinc injection was carried out to the reactor coolant system from 1999, just after the third chemical decontamination of Fugen NPS. The establishment of these water chemistry control techniques ensured the suppression of stress corrosion cracking of the reactor coolant system. At the same time, it reduced the dose of radiation to which workers who are engaged in the periodical inspection outage at Fugen NPS are exposed. (author)

  19. Long-term changes in water and soil chemistry in spruce and beech forests, Solling, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Wesselink, L.G.; Meiwes, K.-J.; Matzner, E.; Stein, A. [Agricultural University Wageningen, Wageningen (Netherlands). Dept. of Soil Science and Geology

    1995-01-01

    With declining sulfur emissions in western Europe, the degree and time scales of reversibility of soil and freshwater acidification are of major interest. We analyzed long-term changes (1969-1991) in the chemistry of bulk precipitation, throughfall water, soil water, and exchangeable base cations in a beech and a spruce forest in Solling, Germany. Time trends in dissolved and exchangeable pools of base cations in the soils were compared with simulations from a simple mechanistic soil chemistry model to identify the processes controlling long-term changes in soil chemistry. In the early 1970s, profound acidification occurred in the spruce and beech soils due to increasing concentrations of dissolved SO{sub 4}. After 1976, atmospheric deposition of SO{sub 4} decreased significantly as a result of reduced industrial emission. Nevertheless, acidification continued in the spruce soil due to declining atmospheric inputs of Ca and Mg and continuously high dissolved SO{sub 4} in the soil. In the beech soil, with lower deposition levels, smaller declines of base cation deposition and a more diluted soil solution, reduced atmospheric inputs of SO{sub 4} in the 1980s started off a recovery of the soil`s base saturation. 23 refs., 3 figs., 4 tabs.

  20. Influence of flow on the synergistic effect of an inhibitive mixture used for water treatment in cooling circuits

    International Nuclear Information System (INIS)

    This work concerned an extensive study of the mechanism of inhibition of a carbon steel in a 200 mg l-1 NaCl solution by a non-toxic multicomponent inhibitor used for water treatment in cooling circuits. The inhibitive formulation was composed of 50 mg l-1 fatty amines associated with 200 mg l-1 phosphonocarboxylic acid salts. The influence of flow and immersion time was investigated by electrochemical impedance spectroscopy with a rotating disc electrode. The results were dependent on the experimental protocol used. Equivalent circuits were used to fit the experimental data. The properties of the protective layer were dependent on the electrode rotation rate and on the immersion time. This behaviour was related to the influence of flow on the anodic kinetics. (authors)

  1. Materials and fabrication sequences for water soluble silicon integrated circuits at the 90 nm node

    International Nuclear Information System (INIS)

    Tungsten interconnects in silicon integrated circuits built at the 90 nm node with releasable configurations on silicon on insulator wafers serve as the basis for advanced forms of water-soluble electronics. These physically transient systems have potential uses in applications that range from temporary biomedical implants to zero-waste environmental sensors. Systematic experimental studies and modeling efforts reveal essential aspects of electrical performance in field effect transistors and complementary ring oscillators with as many as 499 stages. Accelerated tests reveal timescales for dissolution of the various constituent materials, including tungsten, silicon, and silicon dioxide. The results demonstrate that silicon complementary metal-oxide-semiconductor circuits formed with tungsten interconnects in foundry-compatible fabrication processes can serve as a path to high performance, mass-produced transient electronic systems

  2. Bulgarian Experience with the Implementation of 235U Higher Enriched Fuel in WWER-1000 (Water Chemistry Aspects)

    International Nuclear Information System (INIS)

    Water chemistry and radiochemistry plant data from the WWER-1000 Units in NPP Kozloduy confirm that a realistic way for satisfactory implementation of 235U high enriched (up to 4.3%) fuel has been found. The main requirements are: implementation of solid neutron burnable absorbers; application of corrosion resistant fuel cladding; and the maintenance of suitable coolant water chemistry. The implementation at NPP Kozloduy is described. (author)

  3. Shippingport Atomic Power Station steam generator tube damage and water chemistry control (1965--1975)

    International Nuclear Information System (INIS)

    The four stainless steel tubed steam generators in the Shippingport Atomic Power Station were replaced in 1964 with larger, horizontal, NiCrFe Alloy 600 tubed units consistent with a power uprating of the plant. Each of the four Alloy 600 tubed units experienced tube leakage attributed to corrosion by water treatment chemicals (sodium phosphates) which concentrated locally on the tubes in inadequately flushed crevices. Corrective and preventive actions include tube plugging, flow blockage, conversion to all-volatile (hydrazine-morpholine) chemistry and replacement of the two steam generators with the straight tube design. Eddy current inspection after four years of all-volatile chemistry use showed a diminished rate of crevice corrosion and no tube denting

  4. Changing carbonate chemistry in ocean waters surrounding coral reefs in the CMIP5 ensemble

    Science.gov (United States)

    Ricke, K.; Schneider, K.; Cao, L.; Caldeira, K.

    2012-12-01

    Coral reefs comprise some of the most biodiverse ecosystems in the world. Today they are threatened by a number of stressors, including pollution, bleaching from global warming and ocean acidification. In this study, we focus on the implications of ocean acidification for the open ocean chemistry surrounding coral reefs. We use results from 13 Earth System Models included in the Coupled Model Intercomparison Project 5 (CMIP5) to examine the changing aragonite saturations (Ωa) of open ocean waters surrounding approximately 6,000 coral reefs. These 13 Earth System Models participating in CMIP5 each have interactive ocean biogeochemistry models that output state variables including DIC, alkalinity, SST, and salinity. Variation in these values were combined with values from the GLODAP database to calculate aragonite, the form of calcium carbonate that corals use to make their skeletons. We used reef locations from ReefBase that were within one degree (in latitude or longitude) of water masses represented both in the GLODAP database and in the climate models. Carbonate chemistry calculations were performed by Dr. James C. Orr (IPSL) as part of a separate study. We find that in preindustrial times, 99.9 % of coral reefs were located in regions of the ocean with aragonite saturations of 3.5 or more. The saturation threshold for viable reef ecosystems in uncertain, but the pre-industrial distribution of water chemistry surrounding coral reefs may nevertheless provide some indication of viability. We examine the fate of coral reefs in the context of several potential aragonite saturation thresholds, i.e., when Ωa_crit equals 3, 3.25, or 3.5. We show that under a business-as-usual scenario Representative Concentration Pathway (RCP) 8.5, the specific value of Ωa_crit does not affect the long-term fate of coral reefs -- by the end of the 21st century, no coral reef considered is surrounded by water with Ωa> 3. However, under scenarios with significant CO2 emissions

  5. Electrochemical corrosion of zircaloys under irradiation and different water chemistry conditions

    International Nuclear Information System (INIS)

    Shadow corrosion is observed in BWRs either on fuel cladding in contact with Inconel spacers or on channel in close proximity to 304 SS control blades. In order to understand the shadow corrosion mechanism, electrochemical corrosion behavior of Zircaloy-2, Alloy X-750 and 304 SS were previously investigated under UV radiation and published previously. In this study, effects of radiation (up to 300 keV photons) and water chemistry on the electrochemical corrosion behavior of Zircaloy-2, Alloy X-750, and 304 SS were investigated. Measurements of corrosion potential, galvanic corrosion and electrochemical impedance were carried out in 0.01M Na2SO4 at 25degC under UV illumination at 5 eV or photon energies from 2.5 keV to 300 keV using synchrotron radiation. Also, similar measurements were performed in high purity water under various water chemistry conditions at 290degC - 300degC by using UV illumination. The results show that the presence of radiation shifted the corrosion potential of Zircaloy-2 and Alloy X-750 in the anodic or cathodic direction, respectively, and increased anodic currents when Zircaloy-2 was galvanically coupled with Alloy X-750 in 0.01M Na2SO4 at 25degC, may cause accelerated corrosion of Zircaloy-2. In addition, the results showed that hydrogen peroxide increased the electrochemical kinetics at Zircaloy-2 surface in high temperature water under UV irradiation. (author)

  6. Evaluation of Main Compositions of Water Chemistry Data By Graphical Methods, Edremit (Balikesir) Alluvial Aquifer System

    Science.gov (United States)

    Ertekin, Can; Sedat Çetiner, Ziya

    2015-04-01

    This case study aims to characterize and compare hydrogeochemistry based on major ion composition belonging to the year of 1970's, 2007 and 2008 for Edremit alluvial aquifer system which lies on the northwestern coast of Anatolia. Graphical representations including Piper, Schoeller, Stiff and Durov diagrams are applied to ease a systematic interpretation of a wide range of well chemistry data sets. In Piper diagram, water types of the aquifer system are mainly dominated with calcium, carbonate-bicarbonate and sulphate ions. Water types of the site are separated as sulphate or carbonate-bicarbonate ion dominated zones for 1970's data. Comparing data of 1970's, 2007 and 2008 the newest data set is clustered into magnesium dominate zone. This is related to relatively deep groundwater chemistry affect probably resulting from long term groundwater withdrawal for irrigation in the aquifer system. The Schoeller diagram portrays differences of the data set of 1970's, 2007 and 2008 more clearly comparing the Piper diagram. In this diagram, higher portions of magnesium and sulphate composition of the well data belonging to the year of 2007 and 2008 are possibly related to deep routes of groundwater flow paths of the site and/or geothermal water mixing. In Durov diagram, the data set was projected to a rectangular shape and it was not immediately clear to differentiate ionic composition of the water. This is not coincidence because the fact that pH values do not change significantly over the years and its contribution is not substantial comparing to major ion chemistry. Finally, application of hydrogeochemical modeling as a further step was touched upon herein to further depict undergone processes and end-members in the whole aquifer system on Edremit Plain. Keywords: Edremit, groundwater, aquifer, hydrogeochemistry, facies

  7. Assessing Changes in Water Chemistry Along the Mountain to Urban Gradient

    Science.gov (United States)

    Gabor, R. S.; Brooks, P. D.; Neilson, B. T.; Barnes, M. L.; Stout, T.; Millington, M. R.; Gelderloos, A.; Tennant, H.; Eiriksson, D.

    2015-12-01

    Throughout the western US, growing population centers rely on mountain watersheds that are already sensitive to hydrologic stressors. We examined rivers along Utah's Wasatch Front over a range of spatial and discharge scales, confusing on the mountain-to-urban transition to identify how urbanization impacts water resources. The rivers we studied all originate in canyons with impact level ranging from minimal human disturbance to roads and open grazing cattle. Each river enters an urban area after leaving the canyon, where there is significantly more anthropogenic impact on the system. As part of an interdisciplinary effort with the iUTAH project, sample sites were selected at intervals along each river and a variety of measurements were made, including basic water chemistry along with discharge, water isotopes, nutrients, and organic matter analysis. By combining physical and chemical parameters we were able to quantify groundwater influence in gaining reaches and how those differ between the mountain and urban environments. We also identified how the urban system impacted hydrologic and biogeochemical processes in the catchment. For example, in Red Butte Creek discharge tripled through gaining reached in the canyon with only small corresponding changes in conductivity or nitrate levels. However in the urban stretch a gaining reach that tripled the discharge corresponded with a doubling in the conductivity and order of magnitude increase in nitrate. The fact that we first see this change in chemistry during a gaining reach, and not in an area full of storm culverts, suggests that urban impact to stream chemistry predominately occurs through the groundwater. Further work will incorporate ecological and climatic data along with the hydrologic and chemical datasets to identify how controls on water resources change along the mountain to urban gradient. By combining this physical information with sociological data we can identify green infrastructure solutions to

  8. Water chemistry and choice of materials for LWR plants; Die Bedeutung der Wasserchemie und Werkstoffwahl fuer Leichtwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, H. [Forschungszentrum Juelich (Germany). Inst. fuer Werkstoffe und Verfahren der Energietechnik

    1999-10-01

    Water Chemistry in a power plant first and foremost serves to avoid corrosion and depositions in the plant systems. The many varieties of corrosion occur at the phase boundary between a material and a plant medium and, later, between the metal-oxide-medium interfaces. In general, a high pH reduces the solubility of corrosion products and promotes the production of protective layers. Different chemical modes of operation are to minimize both corrosion and the production of interfering depositions. These modes include operation in the alkaline regime at a pH above 9.5, and the neutral mode in which oxygen dissolved in highly purified water promotes the production of stable protective oxide layers. The neutral mode of operation is employed in boiling water reactors which have very pure feedwater and reactor circuit water because of their additional condensate demineralizer system. The corrosion phenomena in LWR plants in recent years aroused particular interest in the cracks detected in pipes made of Ti-stabilized 1.4541 steel exposed to the hot reactor water. Most of them were found to be intergranular stress corrosion cracks in circumferential welds. All pipe systems exhibiting cracks were replaced by Nb-stabilized 1.4550 steel. A modified welding technique was employed with minimum heating of the base metal. (orig.) [German] Wichtigste Aufgabe der Wasserchemie in einem Kraftwerk ist die Vermeidung von Korrosion und Ablagerungen in den Betriebskreislaeufen. Korrosion in ihren verschiedenen Formen findet an der Phasengrenze zwischen Werkstoff und Betriebsmedium, spaeter zwischen den Grenzschichten Metall-Oxid-Medium statt. Allgemein gilt, dass ein hoher pH-Wert die Loeslichkeit von Korrosionsprodukten verringert und die Bildung von Schutzschichten foerdert. Mit unterschiedlichen chemischen Fahrweisen soll sowohl Korrosion als auch unerwuenschte Belagsbildung minimiert werden. Dazu gehoeren u.a. die alkalische Fahrweise mit einem ph-Wert ueber 9.5 und die Neutrale

  9. Chemistry and acidity of cloud water at Mount Washington, NH. Technical completion report

    International Nuclear Information System (INIS)

    Cloud water and mixed wet deposition samples were collected at the summit of Mount Washington during the summer months of 1987, 1988 and 1989. Cloud water deposition measurements were also conducted in a balsam fir krummholz community on the west slope of Mt. Washington from July to September, 1988. Acidity, major ion chemistry and organic acid analyses were conducted on cloud water and precipitation samples collected at the summit. Cloud water pH levels as low as 2.7 were recorded. It was found that vegetation at this high elevation site may be exposed to very acidic cloud water (pH2.7-3.5) deposition for continuous periods as long as 14 hours. The acidity and ionic content of cloud water samples was typically observed to be substantially greater than that of attendant rain. The pH of cloud water samples varied from 2.7-6.4. The high pH, low acidity samples were typically collected under conditions where orographic clouds formed close to the summit as air swept up the mountain and cooled, resulting in condensation and cloud formation. The SO4/NO3 ratio of cloud water changes drastically over short time periods

  10. Natural and anthropogenic sources and processes affecting water chemistry in two South Korean streams

    International Nuclear Information System (INIS)

    Acid mine drainage (AMD) in a watershed provides potential sources of pollutants for surface and subsurface waters that can deteriorate water quality. Between March and early August 2011, water samples were collected from two streams in South Korea, one dominantly draining a watershed with carbonate bedrock affected by coal mines and another draining a watershed with silicate bedrock and a relatively undisturbed catchment area. The objective of the study was to identify the sources and processes controlling water chemistry, which was dependent on bedrock and land use. In the Odae stream (OS), the stream in the silicate-dominated catchment, Ca, Na, and HCO3 were the dominant ions and total dissolved solids (TDS) was low (26.1–165 mg/L). In the Jijang stream (JS), in the carbonate-dominated watershed, TDS (224–434 mg/L) and ion concentrations were typically higher, and Ca and SO4 were the dominant ions due to carbonate weathering and oxidation of pyrite exposed at coal mines. Dual isotopic compositions of sulfate (δ34SSO4 and δ18OSO4) verified that the SO4 in JS is derived mainly from sulfide mineral oxidation in coal mines. Cl in JS was highest upstream and decreased progressively downstream, which implies that pollutants from recreational facilities in the uppermost part of the catchment are the major source governing Cl concentrations within the discharge basin. Dual isotopic compositions of nitrate (δ15NNO3 and δ18ONO3) indicated that NO3 in JS is attributable to nitrification of soil organic matter but that NO3 in OS is derived mostly from manure. Additionally, the contributions of potential anthropogenic sources to the two streams were estimated in more detail by using a plot of δ34SSO4 and δ15NNO3. This study suggests that the dual isotope approach for sulfate and nitrate is an excellent additional tool for elucidating the sources and processes controlling the water chemistry of streams draining watersheds having different lithologies and land

  11. Mercury cycling in stream ecosystems. 1. Water column chemistry and transport

    Science.gov (United States)

    Brigham, M.E.; Wentz, D.A.; Aiken, G.R.; Krabbenhoft, D.P.

    2009-01-01

    We studied total mercury (THg) and methylmercury (MeHg) in eight streams, located in Oregon, Wisconsin, and Florida, that span large ranges in climate, landscape characteristics, atmospheric Hg deposition, and water chemistry. While atmospheric deposition was the source of Hg at each site, basin characteristics appeared to mediate this source by providing controls on methylation and fluvial THg and MeHg transport. Instantaneous concentrations of filtered total mercury (FTHg) and filtered methylmercury (FMeHg) exhibited strong positive correlations with both dissolved organic carbon (DOC) concentrations and streamflow for most streams, whereas mean FTHg and FMeHg concentrations were correlated with wetland density of the basins. For all streams combined, whole water concentrations (sum of filtered and particulate forms) of THg and MeHg correlated strongly with DOC and suspended sediment concentrations in the water column. ?? 2009 American Chemical Society.

  12. WATER CHEMISTRY AND MICROBIAL ASSAY OF DOMESTIC WATER SUPPLY IN GULBARGA CITY, KARNATAKA

    Directory of Open Access Journals (Sweden)

    Zeba Perveen,

    2016-03-01

    Full Text Available The biological contamination in drinking water is a major problem of public health in developing world. WHO estimates that about 1.1 billion people globally drink unsafe water and the majority of diarrheal disease in the world (88% is attributable to unsafe water, sanitation and hygiene (WHO 2003.The pace of urbanization is increasing globally, pulling more pressure on local water quality .The study was conducted to assess the water quality values of different areas in Kalaburagi city Karnataka.different standard scientific test were conducted for each sample.

  13. Determination of water chemistry parameters which influence on failure intensity of RBMK equipment

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, S.M.; Kritski, V.G.; Berezina, I.G.; Stjazhkin, P.S.; Olejnik, P.V. [All-Russian Design and Scientific Research Inst. of Complex Power Technology (VNIPIET), St. Petersburg (Russian Federation)

    2002-07-01

    The coolant quality has an effect on intensity of austenitic stainless steel intergranular corrosion. The correlation between rate of intergranular stress corrosion cracking and water electro-conductivity (on generalized data) for non-stabilized stainless steel 304SS type and stabilized stainless steel X18H10T type is shown in Fig. 1. The cracking rate is increased with electro-conductivity rise and this is equivalently to reduction of pipelines lifetime, increase of amount and depth of cracks in welds. The increased values of water electro-conductivity correspond to high concentrations of iron corrosion product, corrosion-active anions (chlorides, sulphates et. al.), arrived to circulation circuit due to failure of equipment elements, for example, of condenser tubes or during start-up. (author)

  14. The Tests of Water Chemistry Effect on Corrosion Behaviour of Cladding

    International Nuclear Information System (INIS)

    To investigate the effect of improved primary water chemistry of PWR on corrosion behaviour of cladding, a project on compatibility of high content water chemistry and advanced cladding materials is in progress in NPIC during recent years. The modified Zr-4 and M5 alloys were tested in water with lithium at 3.50-6.48mg/L and boron at 983-3000mg/L for 3000 hours. For simulation of water-vapor environment around the surface of cladding, electrical heating elements were manufactured from modified Zr-4 and M5 cladding tubes. These elements were tested in water loops at 310oC and 15.5MPa with surface temperature of 346oC. The test results revealed that high concentration of lithium at same pH will accelerate the general corrosion rate and the hydrogen pick-up to a certain extent. Variation of pH300oC from 6.5 to 7.2 had no obvious influence on corrosion rate at 3.50 mg/l lithium. But the weight loss occurred when the boric acid content decreased to 6.48mg/l lithium. The weight gain difference between M5 and modified Zr-4 in single water phase was imperceptible. The thicker oxide layer with heavy deposits was formed on the boiling section of M5 elements; however the hydrogen absorption did not exceed that of modified Zr-4. It may imply that the M5 alloy is more sensitive to 'oxidation introduced deposition' under sub-cooled nucleate boiling condition, especially when oxygen is saturated. (author)

  15. Fog and rain water chemistry at Mt. Fuji: A case study during the September 2002 campaign

    Science.gov (United States)

    Watanabe, Koichi; Takebe, Yusaku; Sode, Nobuhiro; Igarashi, Yasuhito; Takahashi, Hiroshi; Dokiya, Yukiko

    2006-12-01

    Measurements of fog and rain water chemistry at the summit of Mt. Fuji, the highest peak in Japan, as well as at Tarobo, the ESE slope of Mt. Fuji in September 2002. The pH of fog and rain water sampled at Mt. Fuji varied over a range of 4.0-6.8. Acidic fogs (pH industrial regions on the Asian continent. The ratio of [SO 42-]/[NO 3-] in the fog water was lower at Tarobo than at the summit. High concentrations of Na + and Cl - were determined in the rain water sampled at the summit, possibly because of the long-range transport of sea-salt particles raised by a typhoon through the middle troposphere. The vertical transport of sea-salt particles would influence the cloud microphysical properties in the middle troposphere. Significant loss of Mg 2+ was seen in the rain water at the summit. The concentrations of peroxides in the fog and rain water were relatively large (10-105 μM). The potential capacity for SO 2 oxidation seems to be strong from summer to early autumn at Mt. Fuji. The fog water peroxide concentrations displayed diurnal variability. The peroxide concentrations in the nighttime were significantly higher than those in the daytime.

  16. Relationships between lake water chemistry and benthic macroinvertebrates in the Athabasca Oil Sands Region, Alberta

    Directory of Open Access Journals (Sweden)

    Keith M. SOMERS

    2010-08-01

    Full Text Available Sulphur and nitrogen emissions in the Athabasca Oil Sands Region (AOSR are a threat to regional lentic ecosystems. Benthic macroinvertebrates have been used successfully elsewhere to monitor the impacts of acid emissions on water bodies and the opportunity exists to implement a regional lentic biomonitoring program in the AOSR. Metrics are often used to assess the impacts of anthropogenic stressors because they describe biological conditions through a variety of measures. The selection of appropriate metrics is an integral component of any biomonitoring program and it depends on the in situ relationships between water chemistry and benthic macroinvertebrates. In order to establish these relationships we compared lake water chemistry parameters with benthic macroinvertebrate communities and metric scores from 32 lakes in the AOSR through Redundancy Analyses. Lake acidity correlates positively with Hyallelidae and negatively with Chironomidae and Oligochaeta while dissolved organic carbon is also an important determinant of benthic macroinvertebrate community composition. A number of metrics were strongly correlated with lake acidity and the following compositional metrics proved to be the most suitable for monitoring acidification in the AOSR: % Diptera, % Oligochaeta, % EPT, Total Ephemeroptera and Total Trichoptera.

  17. Effect of hydrogen water chemistry on ultrasonic response for intergranular stress corrosion cracking

    International Nuclear Information System (INIS)

    Hydrogen water chemistry (HWC) is one of the approaches to control BWR water chemistry, which reduces the oxidizing power of the water to a level at which intergranular stress corrosion cracking (IGSCC) (initiation and growth) is effectively suppressed. In this treatment, hydrogen gas is injected into the feedwater to lower the electrochemical corrosion potential (ECP) of stainless steel components. The objective of this work is to experimentally document the effect of HWC on IGSCC detectability. Two pipe samples (pipe sectors B, C) were fabricated from a 12-inch Type 304 stainless steel pipe weldment containing a range of circumferential and axial cracks induced by the Creviced Piped Test. Initial characterization of IGSCC was performed for both pipes by UT and PT prior to application of HWC treatments. For each sample two separate UT methods were used. One was a manual technique that represents field practice, and the other was a laboratory technique that produced ultrasonic images of each crack. Both samples were subjected to a normal BWR water chemistry (NWC) for 168 hours before the HWC treatments. After NWC, one IGSCC sample B was treated for a period of 500 hours with a normal HWC condition (HWC-1) having electrochemical potential (ECP) value of about -0.60 volts (SHE) with Pt reference electrode, water dissolved oxygen content of less than 20 ppb, and water conductivity of less than 0.3 micro-S/cm. The other IGSCC sample C was treated for a period of 500 hours with an off-normal HWC condition (HWC-2) having ECP value of about -0.30 volts (SHE) with Pt reference electrode, and water conductivity of less than 0.3 micro-S/cm. (same as HWC-1). After the HWC treatments, the two IGSCC pipe samples were ultrasonically characterized in the exact manner that was done in the initial characterization to determine if there were any noticeable changes in the UT response of the cracks as indicated by their sizes and signal amplitudes

  18. Rapid changes in surface water carbonate chemistry during Antarctic sea ice melt

    OpenAIRE

    Jones, Elizabeth M.; Bakker, Dorothee C. E.; Venables, Hugh J.; Whitehouse, Michael J.; Korb, Rebecca E.; Watson, Andrew J.

    2011-01-01

    The effect of sea ice melt on the carbonate chemistry of surface waters in the Weddell–Scotia Confluence, Southern Ocean, was investigated during January 2008. Contrasting concentrations of dissolved inorganic carbon (DIC), total alkalinity (TA) and the fugacity of carbon dioxide (fCO2) were observed in and around the receding sea ice edge. The precipitation of carbonate minerals such as ikaite (CaCO3·6H2O) in sea ice brine has the net effect of decreasing DIC and TA and increasing the fCO2 i...

  19. Settling and growth of D. polymorpha in the raw water circuits of the Cattenom nuclear power plant (Moselle, France)

    International Nuclear Information System (INIS)

    A''biological profile'' of the zebra mussels which are infesting certain circuits of the Cattenom nuclear power plant has been provided by data collected during a three-year measurement programme (1991-1993). The larval settlement periods and the growth of settled mussels were monitored. A simple mathematical model, which calculates the shell growth on the long term, was calibrated with the field data. It is based on three functions representing the effect of the initial size, water temperature and fool availability (plankton chlorophyll a). (authors). 13 refs., 7 figs., 4 tabs

  20. Glycol-Water Interactions and co-existing phases and Temperature Dependent Solubility. An Example Of Carbon-Hydrogen Chemistry In Water

    CERN Document Server

    Michael, Fredrick

    2010-01-01

    Recently there has been great interest in Glycol-Water chemistry and solubility and temperature dependent phase dynamics. The Glycol-Water biochemistry of interactions is present in plant biology and chemistry, is of great interest to chemical engineers and biochemists as it is a paradigm of Carbon-Hydrogen Water organic chemistry. There is an interest moreover in formulating a simpler theory and computation model for the Glycol-Water interaction and phase dynamics, that is not fully quantum mechanical yet has the high accuracy available from a fully quantum mechanical theory of phase transitions of fluids and Fermi systems. Along these lines of research interest we have derived a Lennard-Jones -like theory of interacting molecules-Water in a dissolved adducts of Glycol-Water system interacting by Hydrogen bonds whose validity is supported at the scale of interactions by other independent molecular dynamics investigations that utilize force fields dependent on their experimental fittings to the Lennard-Jones ...

  1. The millennium water vapour drop in chemistry-climate model simulations

    Science.gov (United States)

    Brinkop, Sabine; Dameris, Martin; Jöckel, Patrick; Garny, Hella; Lossow, Stefan; Stiller, Gabriele

    2016-07-01

    This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop") and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM) EMAC (ECHAM/MESSy Atmospheric Chemistry Model). The model simulations differ with respect to the prescribed sea surface temperatures (SSTs) and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer-Dobson circulation (BDC). We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST) changes due to a coincidence with a preceding strong El Niño-Southern Oscillation event (1997/1998) followed by a strong La Niña event (1999/2000) and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO) in 2000. Correct (observed) SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution) is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics. Our free

  2. Physical chemistry of water droplets in wafer cleaning with low water use

    NARCIS (Netherlands)

    Donck, J.C.J. van der; Bakker, J.; Smeltink, J.A.; Kolderweij, R.B.J.; Zon, B.C.M.B. van der; Kleef, M.H. van

    2015-01-01

    Reduction of water and energy consumption is of importance for keeping viable industry in Europe. In 2012 the Eniac project Silver was started in order to reduce water and energy consumption in the semiconductor industry by 10% [1]. Cleaning of wafers is one of the key process steps that require a h

  3. Microbiology of Broiler Carcasses and Chemistry of Chiller Water as Affected by Water Reuse

    Science.gov (United States)

    A study was conducted to determine the effects of treating and reusing poultry chiller water in a commercial poultry processing facility. Broiler carcasses and chiller water were obtained from a commercial processing facility which had recently installed a TOMCO Pathogen Management SystemJ to recyc...

  4. Development of water chemistry data management system and its operational experience

    International Nuclear Information System (INIS)

    The demands on the water chemistry data management in a nuclear power plant have increased every year to ensure the safe and stabilized operation of the nuclear power plant. To increase the reliability of the fuel and equipment, dose reduction, and reduce radioactive waste are some of its objectives. Chemical data evaluation and diagnosis have been conducted by personnel experienced in water chemistry management. In view of these, we planned the development of data processing system which diagnoses the plant by detecting minute indications at an early stage to support the plant operation division and the chemical engineering division. A prototype system has been introduced into Tsuruga Power Station No. 2 unit (PWR, 1.160 MWe), in 1986. Based on this experience, a new system has been developed for both Tsuruga Power Station No. 1 unit (BWR, 357 MWe) and Tokai Second Power Station (BWR, 1.100 MWe), which diagnose the plants by means of chemical symptoms in addition to the same functions as Tsuruga Power Station unit No. 2 has had. This system has been being under partial operation since Apr. 1993. The development and situation after the introduction are reported as follows. (authors). 1 fig., 1 tab., 2 refs

  5. The radiation chemistry of heterogeneous and homogeneous nitrogen and water systems

    International Nuclear Information System (INIS)

    Measurements were made of the radiation chemical products such as nitric acid formed when nitrogen gas mixtures in the presence of water vapour and liquid were irradiated with the mixed neutron/gamma field of the BEPO reactor to doses of ca 1021 to 1023 eVg-1. The water was analysed for NO3-, NO2- and NH4+ ions, also for H2O2, NH2OH and N2H4. The investigation was aimed at obtaining information relevant to the DIDO and PLUTO reactors, but the results are of more general interest. The results are discussed in terms of reactions to be expected, especially those of N atoms, and are compared with those of other work on radiation and gas discharge chemistry. (author)

  6. Modeling water chemistry change and contaminant transport in riverbank filtration systems

    Science.gov (United States)

    Mustafa, Shaymaa; Bahar, Arifah; Aziz, Zainal Abdul; Suratman, Saim

    2016-06-01

    Riverbank filtration system is river water treatment approach based on natural removal of contaminants due to physical, chemical and biological processes. In this article, an analytical model is developed by using Green's function method to simulate the effects of pumping well and microbial activity that occurs in riverbed sediments on contaminant transport and evolution of water chemistry. The model is tested with data collected previously for RBF site in France. The results are compared with numerical simulation conducted in the literature by using finite difference method. Graphically, it is noticed that both numerical and analytical results have almost the same behavior. Also it is found that the model can simulate the decreasing of one pollutant concentration at the zone where the bacteria starts to consume this pollutant.

  7. Water chemistry in heat and cold supply (district heating/cooling)

    Energy Technology Data Exchange (ETDEWEB)

    Deelen-Bremer, Marga van; Vos, Frank de; Heijboer, Rob [KEMA Nederland B.V. (Netherlands)

    2010-07-01

    District heating is seen as an important pillar in the CO{sub 2} reduction. Since the Kyoto protocol with the target for reduction of greenhouse gases, a renewed interest in district heating is visible. District heating and increasingly district cooling can be used for heating/cooling of houses, but also for large buildings and greenhouses. Combined heat and power (CHP), waste incinerator, but also rest heat of industry can provide the heat for district heating. On the other hand cold surface water, groundwater, but also rest heat can be used for district cooling. With the growing heat/cold supply market, also an even larger growth in cases of damages in district heating systems is wittnessed. Damages were chemistry can play an preventing role. A good conditioning of the district heating water, combined with proper monitoring, will safeguard the integrity of the system. (orig.)

  8. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2001-01-01

    Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

  9. Steam generator materials and secondary side water chemistry in nuclear power stations

    International Nuclear Information System (INIS)

    The main purpose of this work is to summarize the European and North American experiences regarding the materials used for the construction of the steam generators and their relative corrosion resistance considering the water chemestry control method. Reasons underlying decision for the adoption of Incoloy 800 as the material for the secondary steam generator system for Atucha I Nuclear Power Plant (Atucha Reactor) and Embalse de Rio III Nuclear Power Plant (Cordoba Reactor) are pointed out. Backup information taken into consideration for the decision of utilizing the All Volatil Treatment for the water chemistry control of the Cordoba Reactor is detailed. Also all the reasonswhich justify to continue with the congruent fosfatic method for the Atucha Reactor are analyzed. Some investigation objectives which would eventually permit the revision of the decisions taken on these subjects are proposed. (E.A.C.)

  10. Application of an industrial gas supply system to a hydrogen water chemistry installation

    International Nuclear Information System (INIS)

    Equipment for a hydrogen gas supply and an oxygen gas supply was adapted to meet operating safety criteria for a hydrogen water chemistry (HWC) application at a boiling water reactor (BWR) plant. The oxygen and hydrogen gases are supplied by vaporizing cryogenic liquid drawn from storage tanks. Cryogenic storage tanks consist of an inner vessel supported within an outer vessel, with insulation in the space between vessels. The supports and product lines on the inner container are small and flexible for heat transfer and thermal flexibility considerations. Cryogenic storage tank systems inherently have low natural frequencies and must be analyzed for dynamic response to site seismic criteria. Equipment modifications to meet application criteria were made without compromising performance. The guidelines for HWC installations were supplemented by a comprehensive design safety review to assess the equipment safeguards required to control potential product releases

  11. Water as Life, Death, and Power: Building an Integrated Interdisciplinary Course Combining Perspectives from Anthropology, Biology, and Chemistry

    Science.gov (United States)

    Willermet, Cathy; Mueller, Anja; Juris, Stephen J.; Drake, Eron; Upadhaya, Samik; Chhetri, Pratik

    2013-01-01

    In response to a request from a campus student organization, faculty from three fields came together to develop and teach an integrated interdisciplinary course on water issues and social activism. This course, "Water as Life, Death, and Power", brought together topics from the fields of anthropology, biology and chemistry to explore…

  12. Test of morpholine treatment of the water-steam circuit in the Fessenheim power station

    International Nuclear Information System (INIS)

    This report describes the comparative tests of chemical treatment by ammonia and morpholine carried out in the Fessenheim station, with the object of limiting the phenomena of erosion-corrosion of the carbon-steel circuits in contact with damp steam observed right from first start-up of the two units of the Fessenheim station. The conclusion is that treatment by morpholine with pH 9.2 to 9.3 in the steam appears to be the only treatment that avoids these erosion-corrosion problems. The theoretical reasons for the effectiveness of this treatment are discussed

  13. On the interaction between fuel crud and water chemistry in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Jiaxin Chen [Studsvik Material AB, Nykoeping (Sweden)

    2000-01-01

    This report has surveyed the current understanding about the characteristics of fuel crud, its deposition and dissolution behaviour, the influences of water chemistry, and the radioactivity transport in nuclear power plants. The references were mainly sought for from the International Nuclear Information System (INIS) database and some internal reports of Studsvik Material AB. The characteristics of fuel crud from discharged fuel rods have been extensively investigated over the last three decades. Fuel crud mainly consists of iron, nickel and chromium oxides. For BWR fuel crud the main phases are hematite and nonstoichiometric nickel ferrite spinels. For PWR fuel crud the main phases are nonstoichiometric nickel ferrite and nickel metal or nickel oxide. Fuel crud is usually thin and relatively porous in the outer layer but dense in the inner layer. Important information is lacking about the adhesion property of crud particles or agglomerates on fuel rods. Little, if any, information is reported about the characteristics of fuel crud before discharging in pool. It is uncertain if the fuel crud can, after pool discharge, largely preserve its characteristics appearing during reactor operation. Deposition behaviour of corrosion products on fuel rods, in both solid particles and ionic forms in reactor water, has been well studied in the simulated reactor water environments without irradiation. The influences on deposition rate of pH, heat flux, particle size, crud concentration, and flow rate have also been studied in detail. Most of the experimental observations may be qualitatively explained by the theories developed. However, the importance of each influencing parameter remains largely unknown in the complicated reactor water environments, because irradiation, among various influencing factors, may play an important role. The behaviour of crud dissolution has been extensively studied in various reactor water environments. Generally speaking, the more easily crud

  14. On the interaction between fuel crud and water chemistry in nuclear power plants

    International Nuclear Information System (INIS)

    This report has surveyed the current understanding about the characteristics of fuel crud, its deposition and dissolution behaviour, the influences of water chemistry, and the radioactivity transport in nuclear power plants. The references were mainly sought for from the International Nuclear Information System (INIS) database and some internal reports of Studsvik Material AB. The characteristics of fuel crud from discharged fuel rods have been extensively investigated over the last three decades. Fuel crud mainly consists of iron, nickel and chromium oxides. For BWR fuel crud the main phases are hematite and nonstoichiometric nickel ferrite spinels. For PWR fuel crud the main phases are nonstoichiometric nickel ferrite and nickel metal or nickel oxide. Fuel crud is usually thin and relatively porous in the outer layer but dense in the inner layer. Important information is lacking about the adhesion property of crud particles or agglomerates on fuel rods. Little, if any, information is reported about the characteristics of fuel crud before discharging in pool. It is uncertain if the fuel crud can, after pool discharge, largely preserve its characteristics appearing during reactor operation. Deposition behaviour of corrosion products on fuel rods, in both solid particles and ionic forms in reactor water, has been well studied in the simulated reactor water environments without irradiation. The influences on deposition rate of pH, heat flux, particle size, crud concentration, and flow rate have also been studied in detail. Most of the experimental observations may be qualitatively explained by the theories developed. However, the importance of each influencing parameter remains largely unknown in the complicated reactor water environments, because irradiation, among various influencing factors, may play an important role. The behaviour of crud dissolution has been extensively studied in various reactor water environments. Generally speaking, the more easily crud

  15. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome.

    Directory of Open Access Journals (Sweden)

    Pan Ji

    Full Text Available A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing. To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9-10 had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome.

  16. Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment

    Science.gov (United States)

    Angelidis, Christine

    2013-04-01

    Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment ANGELIDIS, C.1, STERLING, S.1, BREEN, A.2, BIAGI, K.1., and CLAIR, T.A.1 1Dalhousie University, christine.angelidis@dal.ca, 2Bluenose Coastal Action Foundation, andrew@coastalaction.org Southwestern Nova Scotia has some of the most acidic freshwaters in North America due to its location downwind of the major emission sources in eastern Canada and the US and due to a resistant geology which offers little acid buffering capacity (Clair et al. 2007). Because of the poor buffering and regionally high runoff values, hydrological events such as snowmelt and rain storms are frequent and can cause sudden changes in water chemistry which can have devastating effects on freshwater biota due to increases in acidity and metals (Dennis and Clair in press). Clair et al. (2001) have estimated the potential frequency of acidic episodes in this region based on a number of hydrological factors, though the technology available at the time to monitor short-term changes was not dependable. Recent advances in equipment have made the assessment of the frequency and severity of acidic episodes easier and more accurate, allowing better interpretation and prediction of hydrogeochemical changes with variations in weather and deposition patterns. Here we take advantage of these recent advances to monitor water chemistry in an experimental catchment, and explore the response to catchment liming. Catchment liming is one way of mitigating the effects of acid deposition in sensitive areas. We limed a 50 ha catchment at a rate of 5 t/ha in the Gold River watershed of southwest Nova Scotia to examine the interactions between application of lime with the geological and climatological conditions of this region and acid episode frequency. In order to assess changes of episode frequency caused by liming, we established two mobile environmental monitoring platforms in the catchment: a control site

  17. H02 WETLAND TREATMENT SYSTEM WATER CHEMISTRY SAMPLING AND RESULTS REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Bach, M; Michael Serrato, M; Eric Nelson, E

    2008-02-15

    The H-02 Wetland Treatment System (Figure 1) is used to remove heavy metals (e.g., copper and zinc) from the H-Area process and storm water discharge. Routine flow enters an equalization basin by inlets on either the east (Location 1) or west end (Location 2). The west end influent constitutes 75% of the average flow into the basin which has an average residence time of approximately 3 days at low pool (i.e., 120 gal/min. through a volume of 0.5 million gallons). The water then exits via the basin outlet on the east end. Next, the water flows to a splitter box (Location 3) which evenly separates the flow between two wetland cells for a design flow of 60 gal/min. per wetland cell with a residence time in the cell of approximately 2 days. The wetland effluent is then combined (Location 4) and flows through a spillway before reaching the National Pollution Discharge Elimination System (NPDES) measurement point near Road 4. During initial operation, it was observed that the pH of the water leaving the equalization basin was elevated compared to the influent pH. Furthermore, the elevated pH remained through the wetland cells so that there was an average pH of 10 leaving the wetland cells during the daytime which exceeds the upper NPDES limit of 8.5. The purpose of the current study was to evaluate the cause of the increase in pH within the equalization basin of the H-02 Wetland Treatment System. Possible mechanisms included algal activity and inorganic chemistry interactions (e.g., interactions with the clay and/or bentonite liner). Water quality parameters were evaluated throughout the H-02 Wetland Treatment system and over time in order to determine the cause of high pH values measured in the basin and wetland. Fluctuations in dissolved oxygen (DO) and accompanying changes in pH would be expected in systems where algae are an influencing factor. An unexpected increase or decrease in the concentration of inorganic substances may indicate operational changes or an

  18. Measuring circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for measuring circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listings

  19. Circuit theory

    International Nuclear Information System (INIS)

    This book is divided into fourteen chapters, which deals with circuit theory of basis, sinusoidal alternating current on cycle and frequency, basics current circuit about R.L, C circuit and resonant circuit, current power, general linear circuit, inductive coupling circuit and vector locus on an alternating current bridge and mutual inductance and coupling coefficient, multiphase alternating current and method of symmetrical coordinates, non-sinusoidal alternating current, two terminal network, four terminal network, transient of circuits, distributed line circuit constant, frequency characteristic and a filter and Laplace transformation.

  20. Hydrogeology, water chemistry, and subsidence of underground coal mines at Huntsville, Missouri, July 1987 to December 1988. Water Resources Investigation

    International Nuclear Information System (INIS)

    Underground coal mining in and near Huntsville, in Randolph County in north-central Missouri, began soon after 1831. Mining in the Huntsville area was at its peak during 1903 and continued until 1966 when the last underground mine was closed and the economically recoverable coals under Huntsville had been mostly, if not completely, removed. The now abandoned mines are of concern to the public and to various State and Federal agencies for two reasons: (1) mine drainage acidifies streams and leaves large, soft, dangerous deposits of iron oxyhydroxides at mine springs and on streambeds (data on file at the Missouri Department of Natural Resources, Land Reclamation Commission), and (2) collapse of mine cavities sometimes causes surface subsidence resulting in property damage or personal injury. To address these concerns, the U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, in 1987 initiated a study to: determine the location of mine springs, the seasonal variation of stream-water chemistry, and the effects of underground-mine water on flow and water quality of nearby ground water and receiving streams; and identify areas susceptible to surface subsidence because of mine collapse. The purpose of the report is to present the findings and data collected for the study

  1. Element mobilization from Bakken shales as a function of water chemistry.

    Science.gov (United States)

    Wang, Lin; Burns, Scott; Giammar, Daniel E; Fortner, John D

    2016-04-01

    Waters that return to the surface after injection of a hydraulic fracturing fluid for gas and oil production contain elements, including regulated metals and metalloids, which are mobilized through interactions between the fracturing fluid and the shale formation. The rate and extent of mobilization depends on the geochemistry of the formation and the chemical characteristics of the fracturing fluid. In this work, laboratory scale experiments investigated the influence of water chemistry on element mobilization from core samples taken from the Bakken formation, one of the most productive shale oil plays in the US. Fluid properties were systematically varied and evaluated with regard to pH, oxidant level, solid:water ratio, temperature, and chemical additives. Element mobilization strongly depended on solution pH and redox conditions and to a lesser extent on the temperature and solid:water ratio. The presence of oxygen and addition of hydrogen peroxide or ammonium persulfate led to pyrite oxidation, resulting in elevated sulfate concentrations. Further, depending on the mineral carbonates available to buffer the system pH, pyrite oxidation could lower the system pH and enhance the mobility of several metals and metalloids. PMID:26866966

  2. Mineralogical Diversity in Lake Pavin: Connections with Water Column Chemistry and Biomineralization Processes

    Directory of Open Access Journals (Sweden)

    Jennyfer Miot

    2016-03-01

    Full Text Available As biominerals are good tracers of microbial interactions with the environment, they may provide signatures of microbial evolution and paleoenvironmental conditions. Since modern analogues of past environments help with defining proxies and biosignatures, we explored microbe mineral interactions in the water column of a maar lake, located in France: Lake Pavin. This lake is considered as a potential Precambrian ocean analogue, as it is ferruginous and meromictic, i.e., stratified with a superficial O2-rich layer (mixolimnion and a deeper permanently anoxic layer (monimolimnion. We combined bulk chemical analyses of dissolved and particulate matter in combination with electron microscopy analyses of the particulate matter at different depths along the water column. The mineralogy changed along with water chemistry, and most of the minerals were intimately associated with microorganisms. Evolution of the redox conditions with depth leads to the successive precipitation of silica and carbonates, Mn-bearing, Fe-bearing and S-containing phases, with a predominance of phosphates in the monimolimnion. This scheme parallels the currently-assessed changes of microbial diversity with depth. The present results corroborate previous studies that suggested a strong influence of microbial activity on mineralogical diversity through extracellular and intracellular biomineralization. This paper reports detailed data on mineralogical profiles of the water column and encourages extended investigation of these processes.

  3. Water Balance Defines a Threshold in Soil Chemistry at a Global Scale

    Science.gov (United States)

    Slessarev, E.; Bingham, N.; Lin, Y.; Schimel, J.; Chadwick, O.

    2015-12-01

    Carefully constrained studies in model landscapes demonstrate the existence of pedogenic thresholds, where small changes in external forcing lead to large changes in soil properties. One important threshold defines the relationship between water balance, the availability of nutrient cations, and soil pH. Across rainfall gradients, the loss of alkali and alkaline earth cations occurs abruptly at a critical water-balance. At this threshold, the removal of exchangeable base cations by leaching outstrips their production from weathering, causing a drop in soil pH. This leaching threshold has never been characterized at a global scale, in part because of the tremendous sampling effort required to overcome the confounding effects of rock chemistry, soil age, and topography outside of carefully constrained environmental gradients. We compile an extensive database of soil pH measurements to show that there is a mean global leaching threshold near an annual water balance of zero. Where evaporative demand exceeds precipitation, soil pH is buffered near values of 8.1, but where precipitation exceeds evaporative demand, soil pH rapidly collapses to values near 5.0. Deviations from the threshold can be explained in terms of climatic variability, soil age, and rock chemistry. Regions with arid climates and acid soil pH correspond to zones of intense, periodic leaching (e.g. strongly monsoonal climates), or to highly weathered continental surfaces that have permanently lost their stock of cations (e.g. Australia). Regions with humid climates and neutral soil pH correspond to young landscapes, or to soils derived from base-rich rock (e.g. the Pacific Rim volcanic belt). These results demonstrate that the leaching threshold is a dominant feature of the Earth's surface, with the potential to affect both natural and human-dominated ecosystems. For instance: the leaching threshold might impose a step-function on the terrestrial response to CO2 fertilization, the capacity of soils to

  4. Electrochemical ion exchanger in the water circuit to measure cation conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Bengtsson, Bernt; Ingemarsson, Rolf; Settervik, Gustav [Ringhals AB, Vaeroebacka (Sweden); Velin, Anna [Vattenfall Research and Development AB, Stockholm (Sweden)

    2011-03-15

    At Ringhals Nuclear Power Plant (NPP), more than four years of successful operation with a full-scale electrode ionization (EDI) unit for the recycling of steam generator blowdown gave the inspiration to modify and scale down this EDI process. As part of this project, the possibility of replacing the cation exchanger columns used for cation conductivity analysis with some small and integrated electrochemical ion exchange cells was explored. Monitoring the cation conductivity requires the use of a small cation resin column upstream of the conductivity probe and is one of the most important analyses at power plants. However, when operating with high alkaline treatment in the steam circuit, there is the disadvantage of rapid exhaustion of the resins, necessitating frequent replacement or regeneration. This causes interruptions in the monitoring and gives rise to a high workload for the maintenance staff. This paper reports on the optimization and testing of two different two-compartment electrochemical cells for possible replacement of the cation resin columns for analyzing cation conductivity in the secondary steam circuit at Ringhals NPP. Field tests during start-up conditions and more than four months of steady operation together with real and simulated tests for impurity influences indicate that an electrical ion exchange (ELIX) process could be successfully used to replace the resin columns in Ringhals while operating with high-pH all-volatile treatment (AVT) using hydrazine and ammonia. Installation of an ELIX system downstream of a particle filter and upstream of a small cation resin column will introduce additional safety and further reduce the maintenance and possible interruptions. Performance of the ELIX process together with other chemical additives (morpholine, ethanolamine, 3-methoxypropylamine, dimethylamine) and dispersants may be further evaluated to qualify the ELIX process as well as steam generator blowdown electrodeionization for wider use in

  5. Electrochemical ion exchanger in the water circuit to measure cation conductivity

    International Nuclear Information System (INIS)

    In Ringhals NPP, more than four years of successful operation with a full-scale EDI for the recycling of steam generator blow down (SGBD) gave the inspiration to modify and 'scale down' this EDI process. This with purpose to explore the possibilities to replace the cation exchanger columns used for cation conductivity analysis, with some small and integrated electrochemical ion-exchange cells. Monitoring the cation conductivity requires the use of a small cation resin column upstream of the conductivity probe and is one of the most important analyses at power plants. However, when operating with high alkaline treatment in the steam circuit, it's connected to the disadvantage of getting the resins rapidly exhausted, with needs to be frequently replaced or regenerated. This is causing interruptions in the monitoring and giving rise to high workload for the maintenance. This paper reports about some optimization and tests of two different two-compartment electrochemical cells for the possible replacements of cation resin columns when analyzing cation conductivity in the secondary steam circuit at Ringhals NPPs. Field tests during start up condition and more than four months of steady operation together with real and simulated test for impurity influences, indicates that a ELectrical Ion Echange process (ELIX) could be successfully used to replace the resin columns in Ringhals during operating with high pH-AVT (All Volatile Treatment), using hydrazine and ammonia. Installation of an ELIX-system downstream a particle filter and upstream of a small cation resin column, will introduce additional safety and further reduce the maintenance with possible interruptions. Performance of the ELIX-process together with other chemical additives (Morpholine, ETA, MPA, DMA) and dispersants, may be further evaluated to qualify the ELIX-process as well as SGBD-EDI for wider use in nuclear applications. (author)

  6. Natural and anthropogenic sources and processes affecting water chemistry in two South Korean streams

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Woo-Jin [Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Ryu, Jong-Sik [Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Mayer, Bernhard [Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Lee, Kwang-Sik, E-mail: kslee@kbsi.re.kr [Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Lee, Sin-Woo [Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883 (Korea, Republic of); Department of Geology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2014-07-01

    Acid mine drainage (AMD) in a watershed provides potential sources of pollutants for surface and subsurface waters that can deteriorate water quality. Between March and early August 2011, water samples were collected from two streams in South Korea, one dominantly draining a watershed with carbonate bedrock affected by coal mines and another draining a watershed with silicate bedrock and a relatively undisturbed catchment area. The objective of the study was to identify the sources and processes controlling water chemistry, which was dependent on bedrock and land use. In the Odae stream (OS), the stream in the silicate-dominated catchment, Ca, Na, and HCO{sub 3} were the dominant ions and total dissolved solids (TDS) was low (26.1–165 mg/L). In the Jijang stream (JS), in the carbonate-dominated watershed, TDS (224–434 mg/L) and ion concentrations were typically higher, and Ca and SO{sub 4} were the dominant ions due to carbonate weathering and oxidation of pyrite exposed at coal mines. Dual isotopic compositions of sulfate (δ{sup 34}S{sub SO4} and δ{sup 18}O{sub SO4}) verified that the SO{sub 4} in JS is derived mainly from sulfide mineral oxidation in coal mines. Cl in JS was highest upstream and decreased progressively downstream, which implies that pollutants from recreational facilities in the uppermost part of the catchment are the major source governing Cl concentrations within the discharge basin. Dual isotopic compositions of nitrate (δ{sup 15}N{sub NO3} and δ{sup 18}O{sub NO3}) indicated that NO{sub 3} in JS is attributable to nitrification of soil organic matter but that NO{sub 3} in OS is derived mostly from manure. Additionally, the contributions of potential anthropogenic sources to the two streams were estimated in more detail by using a plot of δ{sup 34}S{sub SO4} and δ{sup 15}N{sub NO3}. This study suggests that the dual isotope approach for sulfate and nitrate is an excellent additional tool for elucidating the sources and processes

  7. Influence of aqueous chemistry on the chemical composition of fog water and interstitial aerosol in Fresno

    Science.gov (United States)

    Kim, Hwajin; Ge, Xinlei; Collier, Sonya; Xu, Jianzhong; Sun, Yele; Wang, Youliang; Herckes, Pierre; Zhang, Qi

    2015-04-01

    A measurement study was conducted in the Central Valley (Fresno) of California in January 2010, during which radiation fog events were frequently observed. Fog plays important roles in atmospheric chemistry by scavenging aerosol particles and trace gases and serving as a medium for various aqueous-phase reactions. Understanding the effects of fog on the microphysical and chemical processing of aerosol particles requires detailed information on their chemical composition. In this study, we characterized the chemical composition of fog water and interstitial aerosol particles to study the effects of fog processing on aerosol properties. Fog water samples were collected during the 2010 Fresno campaigns with a Caltech Active Strand Cloud water Collector (CASCC) while interstitial submicron aerosols were characterized in real time with an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a scanning Mobility Particle Sizer (SMPS). The fog water samples were later analyzed using the HR-ToF-AMS, ion chromatography, and a total carbon analyzer. The chemical composition and characteristics of interstitial particles during the fog events were compared to those of dissolved inorganic and organic matter in fog waters. Compared to interstitial aerosols, fog water is composed of a higher fraction of ammonium nitrate and oxygenated organics, due to aqueous formation of secondary aerosol species as well as enhanced gas-to-particle partitioning of water soluble species under water rich conditions. Sulfate is formed most efficiently in fog water although its contribution to total dissolved mass is relatively low. The HR-ToF-AMS mass spectra of organic matter in fog water (FOM) are very similar to that of oxygenated organic aerosols (OOA) derived from positive matrix factorization (PMF) of the HR-ToF-AMS spectra of ambient aerosol (r2 = 0.96), but FOM appears to contain a large fraction of acidic functional groups than OOA. FOM is also enriched of

  8. Influence of feed water distribution pipe replacement on the water chemistry in the steam generator at Loviisa NPP

    International Nuclear Information System (INIS)

    Imatran Voima Oy , (IVO) operates two Russian designed nuclear power plants of type VVER440/213. Unit 1 has been operating since 1977 and unit 2 since 1981. First damage of feed water distribution (FWD) pipes was observed in 1989. In closer examinations FWD-pipe T-connection and distribution nozzles suffered from severe erosion corrosion damage. Similar damages have been found also in other VVER-440 type NPPs. In 1994 the first FWD-pipe was replaced by a new design mounted over the tube bundle instead of the old FWD-pipe, which was located inside the tube bundle. The purpose of this paper is to describe the new FWD-pipe and discuss its effects on the steam generator chemistry. (author)

  9. Water Quality of NPP Secondary Side with Combined Water Chemistry of Ammonia and Ethanolamine

    International Nuclear Information System (INIS)

    Ammonia (AM) and Ethanolamine (ETA), as pH control additive agents, were injected to the secondary side in a Korean NPP for the even pH in the entire secondary system including the wet region and the condensate. Ammonia and ETA are dominant in the vapor and liquid phases, respectively, since the former and latter are more and less volatile than water in the temperature range of 30 to 300 . pH of 9.5 to 9.7 was maintained in the water-steam cycle at the concentrations of ammonia with ∼1.0 ppm and ETA of ∼1.8 ppm. From the standpoint of corrosion, i.g, concentration of Fe, the water quality of secondary side was improved by the combined water treatment of ammonia and ETA, compared to all volatile treatment of ammonia. The electrical conductivity was increased from 6 to 10 μS/cm due to the presence of organic carboxylates produced by the decomposition of ETA. ETA was broken down by <5% in steam generator and converted into formate, acetate, and glycolate, among which acetate was largely formed. But inorganic ions such as Na+, Cl-, and SO42- are not changed because their ingress was not made and the selectivity of resin over those ions was not fairly altered. The runtime of demineralizer in steam generator blowdown was shortened by a third for a mixture of ammonia and ETA. Most of Fe was originated from the shell side of heat exchangers including the condenser as a result of corrosion. Fe was only eliminated by ion exchange demineralizers, i.e., 46% at CPP and 3% at SG BD and 70% of Fe oxides were accumulated at the steam generator, on the basis of Fe concentration at the final feedwater. In conclusion, ETA is preferable to ammonia for the enhancement of pH in the liquid phase of water-steam mixture such as the shell side of heat exchanger and also the full-flow operation of CPP is more desirable than partial-flow operation for the improved removal of corrosion products, regardless of hydrogen- or amine-type operation. (authors)

  10. Dependence of Corrosion Behavior of SiC Ceramics on PWR Water Chemistry

    International Nuclear Information System (INIS)

    There have also been efforts on applying the SiCf/SiC composites to the light water reactor (LWR) fuel cladding and guide tubes as well as channel boxes for fuel assembly of the boiling water reactor (BWR). In spite of potential benefits of the SiC composite cladding, there are a lot of technical issues that need to be clarified for the LWR application because the previous research on the SiCf/SiC composite has mostly been focused on high-temperature application. Especially, the corrosion resistance in the PWR water is an important parameter to insure the cladding performance under normal operating condition. Generally, SiC ceramics are highly corrosion resistant by forming a protective SiO2 layer in an air atmosphere. However, the corrosion resistance of SiC is largely dependent on the fabrication route of SiC and the exact environmental condition. For example, in a high-temperature and high-pressure water or a steam environment, the corrosion resistance of SiC is decreased because the protectiveness of the SiO2 layer is deteriorated. Until now, the exact corrosion behavior of SiC in high temperature water is not clear due to the differences in the test samples and conditions. The kinetics of the SiC corrosion in an LWR condition, therefore, needs to be defined to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In this study, we evaluated the corrosion behavior of SiC-based ceramics fabricated by various routes. We also examined the effect of PWR water chemistry on the corrosion resistance of SiC

  11. Water Chemistry Control System for Recovery of Damaged and Degraded Spent Fuel

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) and the government of Serbia have led the project co-sponsored by the U.S, Russia, European Commission, and others to repackage and repatriate approximately 8000 spent fuel elements from the RA reactor fuel storage basins at the VINCA Institute of Nuclear Sciences to Russia for reprocessing. The repackaging and transportation activities were implemented by a Russian consortium which includes the Sosny Company, Tekhsnabeksport (TENEX) and Mayak Production Association. High activity of the water of the fuel storage basin posed serious risk and challenges to the fuel removal from storage containers and repackaging for transportation. The risk centered on personnel exposure, even above the basin water, due to the high water activity levels caused by Cs-137 leached from fuel elements with failed cladding. A team of engineers from the U.S. DOE-NNSA's Global Threat Reduction Initiative, the Vinca Institute, and the IAEA performed the design, development, and deployment of a compact underwater water chemistry control system (WCCS) to remove the Cs-137 from the basin water and enable personnel safety above the basin water for repackaging operations. Key elements of the WCCS system included filters, multiple columns containing an inorganic sorbent, submersible pumps and flow meters. All system components were designed to be remotely serviceable and replaceable. The system was assembled and successfully deployed at the Vinca basin to support the fuel removal and repackaging activities. Following the successful operations, the Cs-137 is now safely contained and consolidated on the zeolite sorbent used in the columns of the WCCS, and the fuel has been removed from the basins. This paper reviews the functional requirements, design, and deployment of the WCCS. (author)

  12. Determination of concentration of radon, volatile organic compounds (VOC) and water chemistry in springs near to Popocatepetl volcano

    International Nuclear Information System (INIS)

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs is analysed as a function of the 2002-2003 volcanic activity. Soil radon indicated fluctuations related both the meteorological parameters and sporadic explosive events. Groundwater radon showed essentially differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed stability along the monitoring period indicating also differences between springs. No anthropogenic pollution from volatile organic compounds was observed. (Author)

  13. Decontamination and Post-Decontamination Water Chemistry Treatment. Final Report on Renew Contract No. 13715/R0 Between IAEA and VNIPIET 2008/08/01-2009/07/31

    International Nuclear Information System (INIS)

    A description of the mass transfer mechanism of corrosion radionuclides in the primary coolant circuit is a complicated problem. Decontamination of the primary equipment due to inspection, repair and replacement work needs leads to a local change of corrosion rates, which results in the increase of corrosion products concentration in the circuit and then in increase of deposits on surfaces. If due to incorrect water chemistry conditions for corrosion products deposition in the core are created, in parallel with increasing activity of the corrosion producet in the coolant the hydraulic resistance of the reactor also grows, which results in the increase of the pressure drop at the reactor. The quantity content of components of deposits on fuel unit A depending on quality cycles is: for Fe from 12,9 to 819 mg/fuel assembly, for Cr from 0,95 to 36,0 mg/fuel assembly, for Ni from 0,75 to 66,0 mg/fuel assembly. The dependence of increase rate of pressure drop from pHT before decontamination and after decontamination is modified. The corrosion mechanism for Zr-Nb alloys shows complex character and depends on many parameters described in detail. The oxidation rate can be expressed as V = dS/dt = kT+kΦ where kT and kΦ are the heat and neutron radiation components respectively. Empirical study of Zr oxidation in water has shown that the temperature dependence on the oxidation rate under constant oxygen pressure in the environment can be described by the Arrenius equation. The radiation component of Zr uniform corrosion equation is a function of several factors such as neutron fluency, the temperature, the metallurgical composition and ets. We assume that the radiation effect on Zr alloy corrosion rate is in changing of coolant chemistry (concentrations of O2, H2, H2O2, NH4OH, LiOH, KOH, pHT and etc.). The general corrosion equation, which take into account the above-mentioned factors for producing a generalised model for calculating Zr alloys corrosion is presented. Model

  14. Water treatments in semi-closed cooling circuits and their impact on the quality of effluents discharged by CERN

    CERN Document Server

    Santos Leite Cima Gomes, J; Kleiner, S

    2008-01-01

    The main goal of this study is to assess the impact of the discharges of the semi-closed water cooling circuits of CERN (European Center for Nuclear Research) on the overall quality of CERN's effluents, taking as guidelines the international legislation supported on the knowledge of the water systems of CERN. In order to reach this goal, a thorough analysis of the functioning of the semi-closed water cooling systems of CERN's particle accelerators was done, as well as, an analysis of the treatment that is done to prevent the proliferation of bacteria such as Legionella. The products used in these water treatments, as well as their impact, were also researched. In addition, a study of the applicable regulation to CERN's effluent was done. This study considered not only the regulation of France and Switzerland (CERN's host states) but also the international regulation from the European community, Portugal Germany, Spain, U.S. and Canada, having in view a better understanding of the limit values of the parameter...

  15. Water chemistry and isotope data from a five year monitoring programme of Bunker Cave, NW Germany

    Science.gov (United States)

    Riechelmann, S.; Schröder-Ritzrau, A.; Spötl, C.; Riechelmann, D. F. C.; Richter, D. K.; Immenhauser, A.

    2012-04-01

    Water chemistry and isotope data from a five year monitoring programme of Bunker Cave, NW Germany Sylvia Riechelmann (1), Andrea Schröder-Ritzrau (2), Christoph Spötl (3), Dana F.C. Riechelmann (4), Detlev K. Richter (1), Adrian Immenhauser (1) (1) Ruhr-University Bochum, Institute for Geology, Mineralogy and Geophysics, Universitätsstraße 150, D-44801 Bochum, Germany (2) Heidelberg Academy of Sciences, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany (3) Leopold-Franzens-University Innsbruck, Institute for Geology and Palaeontology, Innrain 52, A-6020 Innsbruck, Austria (4) Johannes Gutenberg-University Mainz, Institute of Geography, Johann-Joachim-Becher-Weg 21, D-55128 Mainz, Germany Monitoring of cave environments is essential to understand the processes taking place in the soil, karst and cave zone and the interpretation of speleothem archives is increasingly based on monitoring data. A five year monitoring programme of Bunker Cave (NW Germany) included monthly sampling of rain, soil and drip water. The delta18O ratios of the drip waters reflect the mean annual delta18O composition of rain water. The weak seasonal pattern in drip water delta18O composition is overlain by a trend to increasing values (approximately 0.3‰ in the monitoring period between 2007 and 2011). Up to the year 2009, rain water delta18O values show an increasing trend. In 2010, the lowest yearly mean delta18O ratio of rain water (-9.20‰) was observed, probably due to cool summer air temperatures and significant amounts of snow fall during winter months 2010. A decrease of the drip water delta18O in the future will expectedly allow to stack both data series and to identify time delay between rain water and drip water series and allow for the quantification of the approximate transfer time of rain water from soil surface into the cave. The Mg2+-concentration of one drip site correlates positively with drip rate. High Mg2+-concentrations occur especially after dry periods (low

  16. Urban and Suburban Influences on Water Chemistry in Washington DC: Impervious Surfaces and Urban Stream Syndrome

    Science.gov (United States)

    MacAvoy, S. E.; Petersen, E.

    2015-12-01

    Among the challenges facing urban rivers are water stormwater runoff problems and changing water chemistry, not only from air and water pollution sources, but also from altered geology with the development of "urban karst". Seventy five percent of the Anacostia River in Washington, D.C. is urban or impervious. The Anacostia River experiences environmental challenges similar to those of other urban industrial rivers (heavy metal, PCB and PAH contamination). It also has Ca/Sr ratios above 200, and Na concentrations higher than Ca, and elevated ionic strength, all associated with extended chemical interaction with concrete. While these chemical characteristics have been documented in the urban areas within DC, they have not been examined in the largely suburban/mixed development tributaries of the Anacostia. Here we examine the base-flow geochemistry of the Anacostia River and its suburban tributaries (6 locations) over a year (November 2014- August 2015), concentrating on the following water chemistry variables: pH, hardness, SAR, alkalinity, Ca, Mg, Na, K, Fe, Mn, Zn, Al, Ba, Ni, total P, S, Sr, NO3-, NH4+, PO43-. NO3- and NH4+ were generally lowest in at all sites in January, but rose to between 0.5 and 2.4 mg/L in June, with highest NO3- concentrations in suburban areas. Na and Cl concentrations were 5x higher in suburban areas than urban areas during the winter months. Ca/Sr concentration ratios, were between 120 and 200 for suburban sites but increased as the sites became more urban (to a high of 240 for the most urban site). These trends have been observed in other urban streams, and correlate with percent impervious area. The data follow patterns expected for "urban stream syndrome" and dissolution of concrete. Suburban areas, with their relatively small streams, show greater winter salting effects than more urban areas down stream. Suburban areas also show higher NO3- (and occasionally higher NH4+) than urban areas except in winter. The data presented here

  17. Effect of water chemistry on corrosion of stainless steel and deposition of corrosion products in high temperature pressurised water

    International Nuclear Information System (INIS)

    temperatures between 200 and 300 deg. C. Finally, it has been recognised that there is an electrokinetic component to the deposition occurring within flow restrictions, but very few investigations have been performed to study the electrokinetic behaviour at a geometric flow restriction. Work that has been previously attempted has focused on electrokinetics of crud deposition in the secondary side water chemistry. This electrokinetic behaviour, manifested as a streaming current, is believed to be influential in the electrochemical reactions occurring at flow restrictions resulting in the formation of the observed crud deposits. As part of this programme a high velocity (up to 30 ms-1) flow rate loop operating at high temperature (up to 315 deg. C) and pressure (up to 150 bar) has been constructed to study the deposition of material at a flow restriction of known geometry under simulated primary side water chemistry, temperature and pressure conditions. Furthermore, to assist in the understanding of measured streaming currents present as a function of desired geometries, preliminary experiments utilising a second 'cold' loop will be performed, where water of up to 373 K will be flowed at high velocity through an instrumented sample section. (authors)

  18. Intelligent monitoring of water chemistry - Diagnostic expert system DIWA{sup TM}

    Energy Technology Data Exchange (ETDEWEB)

    Metzner, W.; Streit, K. [FRAMATOME ANP (France)

    2002-07-01

    For fast and comprehensive evaluation of power plant water chemistry conditions and reliable diagnosis in the event of disturbances considerable advantages are provided by employment of the Diagnostic Expert System DIWA. The interface to the process control system (I and C) and the integration of the DIWA system in the office PC network are the preconditions that DIWA operates as a monitoring system in real time. The performance of diagnosis, which are processed by a fuzzy-logic-supported knowledge base ensures not only the detection of all disturbances but also different analyses of the plant operation mode. By editing the knowledge base the Al of the system can increase without system programming. (authors)

  19. Radiation chemistry of water at low dose rates with emphasis on the energy balance

    International Nuclear Information System (INIS)

    There has been considerable interest in absorbed dose water calorimetry. In order to accurately relate the temperature change to the absorbed dose, the energy balance of the overall chemistry of the system must be known. The radiolytic products and their yields are affected by dose rate, dose and added solutes. The yields of the radiolytic products have been calculated using a computer program developed at Atomic Energy of Canada. The chemical energy balance was determined as a function of dose for various dose rates and initial concentrations of hydrogen (H2), oxygen (O2), and hydrogen peroxide (H2O2). In solutions containing H2O2 or O2 and H2 the chemical reactions were exothermic; in other cases they were endothermic. Approach to equilibrium and equilbrium conditions are discussed

  20. Effects of water chemistry on arsenic removal from drinking water by electrocoagulation.

    Science.gov (United States)

    Wan, Wei; Pepping, Troy J; Banerji, Tuhin; Chaudhari, Sanjeev; Giammar, Daniel E

    2011-01-01

    Exposure to arsenic through drinking water poses a threat to human health. Electrocoagulation is a water treatment technology that involves electrolytic oxidation of anode materials and in-situ generation of coagulant. The electrochemical generation of coagulant is an alternative to using chemical coagulants, and the process can also oxidize As(III) to As(V). Batch electrocoagulation experiments were performed in the laboratory using iron electrodes. The experiments quantified the effects of pH, initial arsenic concentration and oxidation state, and concentrations of dissolved phosphate, silica and sulfate on the rate and extent of arsenic removal. The iron generated during electrocoagulation precipitated as lepidocrocite (γ-FeOOH), except when dissolved silica was present, and arsenic was removed by adsorption to the lepidocrocite. Arsenic removal was slower at higher pH. When solutions initially contained As(III), a portion of the As(III) was oxidized to As(V) during electrocoagulation. As(V) removal was faster than As(III) removal. The presence of 1 and 4 mg/L phosphate inhibited arsenic removal, while the presence of 5 and 20 mg/L silica or 10 and 50 mg/L sulfate had no significant effect on arsenic removal. For most conditions examined in this study, over 99.9% arsenic removal efficiency was achieved. Electrocoagulation was also highly effective at removing arsenic from drinking water in field trials conducted in a village in Eastern India. By using operation times long enough to produce sufficient iron oxide for removal of both phosphate and arsenate, the performance of the systems in field trials was not inhibited by high phosphate concentrations. PMID:20800261

  1. Investigations into experimental steam generators for secondary water chemistry in pressurized water reactors

    International Nuclear Information System (INIS)

    Since 1981 investigations have been carried out on boiler models, which correspond in thermo-dynamic design to the boilers in nuclear power stations with Kraftwerk Union pressurized water reactors (PWR). The object of this experiment is to investigate in detail the effects of chemical operation in the secondary cycle of the PWR on the boilers and to test different conditioning procedures. Three test cycles have so far been undertaken over a three month period. The boilers have been operated using three different conditioning procedures, which were maintained for all cycles. This paper discusses the design of the experimental plant, its commissioning and the first three cycles. (orig.)

  2. Supramolecular organic frameworks: engineering periodicity in water through host-guest chemistry.

    Science.gov (United States)

    Tian, Jia; Chen, Lan; Zhang, Dan-Wei; Liu, Yi; Li, Zhan-Ting

    2016-05-11

    The development of homogeneous, water-soluble periodic self-assembled structures comprise repeating units that produce porosity in two-dimensional (2D) or three-dimensional (3D) spaces has become a topic of growing interest in the field of supramolecular chemistry. Such novel self-assembled entities, known as supramolecular organic frameworks (SOFs), are the result of programmed host-guest interactions, which allows for the thermodynamically controlled generation of monolayer sheets or a diamondoid architecture with regular internal cavities or pores under mild conditions. This feature article aims at propagating the conceptually novel SOFs as a new entry into conventional supramolecular polymers. In the first section, we will describe the background of porous solid frameworks and supramolecular polymers. We then introduce the self-assembling behaviour of several multitopic flexible molecules, which is closely related to the design of periodic SOFs from rigid multitopic building blocks. This is followed by a brief discussion of cucurbit[8]uril (CB[8])-encapsulation-enhanced aromatic stacking in water. The three-component host-guest pattern based on this stacking motif has been utilized to drive the formation of most of the new SOFs. In the following two sections, we will highlight the main advances in the construction of 2D and 3D SOFs and the related functional aspects. Finally, we will offer our opinions on future directions for both structures and functions. We hope that this article will trigger the interest of researchers in the field of chemistry, physics, biology and materials science, which should help accelerate the applications of this new family of soft self-assembled organic frameworks. PMID:27094341

  3. Use of an on-line Fuzzy-logic expert system for water chemistry

    International Nuclear Information System (INIS)

    The requirements for availability and operating economy of power plants have become steadily more stringent over the last few years. In addition to technological advances (e.g. in the form of new design measures, processes and materials), manufacturers have also increasingly applied secondary measures to enhance the safety and operating economy of power plant units. These include ever more sophisticated process monitoring and analytical systems and, (in recent times) diagnostic systems which perform continuous assessment of the plant condition to allow imminent changes that cam lead to damage and faults to be detected at the earliest possible time. The following paper presents an expert system, based on Fuzzy logic, which is used to perform a wide variety of tasks in the field of NPP water chemistry diagnostics. Thanks to the general nature of the approach selected, the system kernel is identical for all solutions which were implemented despite the wide variety of tasks and their diverse needs. This would not have been possible without the development and application of powerful and flexible engineering tools which can provide solutions to different types of problems at no extra effort. It will be shown in which way the system builds up diagnoses from the collected on-line data via a system -specific and easy- to-learn language and several tools. The presented module DIWA (Diagnostic System of Water Chemistry) was directly derived from the DIGEST system (diagnostic expert system for turbomachinery), which was developed over the last few years at the Power Generation Group (KWU) of the Siemens AG. (author)

  4. Experimental proposals for procedures to investigate the water chemistry, sorption and transport properties of marl

    International Nuclear Information System (INIS)

    The aim of this report is to describe a framework within which laboratory studies on groundwater chemistry, sorption and transport properties might be conducted on samples from rock formations being considered as potential 'host rocks' for the disposal of radioactive waste. Here, Valanginian marl, has been taken as a specific example, but the general principles should be applicable to other systems. Some brief notes are given on sampling and handling procedures and mineralogical characterisation. This is followed by a detailed discussion of the procedures considered necessary to determine a groundwater chemistry of a specific rock matrix. The methods described are particularly appropriate to rocks such as marl i.e. low water content rocks (essentially 'dry') with appreciable clay and carbonate contents. An important conclusion drawn is that simple aqueous phase extractions at different liquid to solid ratios, followed by extrapolation procedures, are not always appropriate and can lead to incorrect water compositions. Some of the uncertainties and difficulties inherently involved in determining sorption parameters from batch, infiltration and diffusion based methods are presented. These methods are then individually discussed in greater detail with some illustrative examples. In the relatively few studies where sorption has been measured in crushed rock tests and compared with the results from intact rock experiments, it is often found that there are discrepancies. An outline for an experiment is described in which results from the two types of test could be quantitatively related to one another via cation exchange capacity measurements. Using this method it might be possible to explain the reasons for such discrepancies. Finally, a brief discussion is given on the possible consequences for experimental studies of gas in Valanginian marl and the swelling of the clay rich components. (author) 8 figs., 4 tabs., 46 refs

  5. Fouling and corrosion problems of raw water circuits of FBTR and RAPS

    International Nuclear Information System (INIS)

    Fouling and corrosion are two major operational problems in the heat exchangers of power plant cooling system. Nuclear power plants are more susceptible to fouling induced corrosion than their thermal counterparts due to their inherent design characteristics like long gestation period, multiple standby systems etc. Problems such as flow blockage of pipes, pipe punctures and relatively high corrosion rates were experienced in the service water system of the Fast Breeder Test Reactor (FBTR) at Kalpakkam. Similarly about 1100 condenser tubes in Rajasthan Atomic Power Station (RAPS) II have failed during two years of operation resulting in leakage (80-2100 l/h) of condenser cooling water into the boiler feed water. As a result of this total dissolved solids (TDS), chloride, total hardness and silica content in the boiler water remained above the specified limit for a good amount of time. In view of the possible linkage between water quality and microbial activity resulting in material degradation, experiments on water quality (Palar subsoil, open reservoir, RAPS intake and out fall), corrosion rate measurements, microbiological counts and experiment on chlorination vs bacterial mortality were carried out with a view to study the effectiveness of existing treatment programme in FBTR cooling system and also to look for possible linkage between water quality and condenser tubes failures of RAPS. 10 refs., 2 tabs., 1 fig

  6. Role of Surface Water-Groundwater Interaction in Regulating Stream Water Chemistry in Urban Streams

    Science.gov (United States)

    Ledford, S. H.; Lautz, L. K.; Holdsworth, M.

    2012-12-01

    Urbanization is a major cause of stream degradation in the United States. Surface water -groundwater interaction may naturally mitigate impaired water quality associated with urbanization. Meadowbrook Creek, in Syracuse, New York, flows along a declining urbanization gradient, from headwaters that are highly channelized with armored banks to an outlet that is unconstrained and meanders through a broad, riparian floodplain. Biweekly, longitudinal stream samples were collected every 100 - 600 m in the summer and every 500 - 1000 m in the winter and analyzed for conductivity and major ions. A five well transect in the downstream floodplain was also sampled. A constant rate tracer test was used to quantify groundwater inflow longitudinally during summer baseflow. Specific conductivity decreased along the urban, channelized reach and then increased along the meandering, unconstrained section during the summer, while the opposite occurred during the winter. Nitrate concentrations along the channelized reach were low to below detection (flood plain during spring snowmelt, resulting in a year-round winter road salt contamination issue. Overall, the geochemistry of the channelized portion of the stream is primarily controlled by surface runoff, while the unconstrained section of Meadowbrook is strongly influenced by discharging groundwater, providing a buffering capacity during winter. Nitrate, however, increases with the presence of riparian vegetation, which has potential implications for stream restoration techniques that aim to increase organic carbon inputs to streams, as organic matter also adds nitrogen to the system.

  7. Water chemistry management of the spent-fuel pool in Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Suparit, Nitaya; Sukharn, Sumalee; Busamongkol, Arporn; Laoharojanaphand, Sirinart [Chemistry Division, Office of Atomic Energy for Peace, Bangkok (Thailand)

    1999-08-01

    Water chemistry of the OAEP spent-fuel pool has been closely monitored without any pre-treatment for its conductivity, pH, temperature, chloride ion, sulfate ion, nitrate ion, phosphate ion, silver ion, and copper ion as well as its gamma activity of Cs-137. Conductivity, pH and temperature were measured using a portable pH and conductivity meter with built in temperature probe. Chloride ion was monitored by an automatic micro-titrator with silver nitrate as titrant and platinum indicator electrode. Nitrate, sulfate and phosphate were analysed by ion-exchange chromatographic method using an anion separator column and salicylate buffer as eluant. Gamma activity of Cs-137 was measured using a Canberra gamma spectrometer with HpGe detector. Silver and copper were analysed by ICP-AES technique within 6 hours after collection. During the study period from March 1996-September 1998, the conductivity was between l.25-4.80 {mu}/cm, pH in the range of 5-8.1, and temperature from 26.4-29.6 degree celsius. Chloride ion was found between 0.l-0.8 ppm. Silver, copper, nitrate, sulfate and phosphate ions were undetectable. Overall chemical composition of the water shows that the water is kept in standard condition recommended for safety storage. However, the presence of gamma activity of Cs-137 (average value of 138 Bq/l) indicates a slight leak of the spent fuel. (author)

  8. Water chemistry management of the spent-fuel pool in Thailand

    International Nuclear Information System (INIS)

    Water chemistry of the OAEP spent-fuel pool has been closely monitored without any pre-treatment for its conductivity, pH, temperature, chloride ion, sulfate ion, nitrate ion, phosphate ion, silver ion, and copper ion as well as its gamma activity of Cs-137. Conductivity, pH and temperature were measured using a portable pH and conductivity meter with built in temperature probe. Chloride ion was monitored by an automatic micro-titrator with silver nitrate as titrant and platinum indicator electrode. Nitrate, sulfate and phosphate were analysed by ion-exchange chromatographic method using an anion separator column and salicylate buffer as eluant. Gamma activity of Cs-137 was measured using a Canberra gamma spectrometer with HpGe detector. Silver and copper were analysed by ICP-AES technique within 6 hours after collection. During the study period from March 1996-September 1998, the conductivity was between l.25-4.80 μ/cm, pH in the range of 5-8.1, and temperature from 26.4-29.6 degree celsius. Chloride ion was found between 0.l-0.8 ppm. Silver, copper, nitrate, sulfate and phosphate ions were undetectable. Overall chemical composition of the water shows that the water is kept in standard condition recommended for safety storage. However, the presence of gamma activity of Cs-137 (average value of 138 Bq/l) indicates a slight leak of the spent fuel. (author)

  9. Hydrograph Separation in the Headwaters of the Shule River Basin: Combining Water Chemistry and Stable Isotopes

    Directory of Open Access Journals (Sweden)

    Jiaxin Zhou

    2015-01-01

    Full Text Available The runoff components were identified in the headwater area of Shule River Basin, using isotopic and chemical tracing with particular focus on the temporal variations of catchment sources. A total of 95 samples, including precipitation, groundwater, and glacial meltwater, were collected and analyzed for stable water isotopes (18O and 2H and major chemical ion parameters (potassium, sodium, calcium, magnesium, sulfate, chloride, and bicarbonate. Based on the isotope and water chemistry data, we applied end member mixing analysis (EMMA to identify and quantify the major runoff generating sources and their contributions. The contributions of groundwater, precipitation, and glacial meltwater were 66.7%, 19.9%, and 13.4%, respectively. The study indicated that groundwater dominated runoff in the headwater area of Shule River Basin. The roles of glacier meltwater should be remarkable in water resource management in this basin. The uncertainties of the EMMA method were summarized and estimated via a classical Gaussian error propagation technique. Analyses suggested that the uncertainty in the measurement method was less important than that in the temporal and spatial variations of tracer concentrations. The uncertainty was sensitive when the difference between mixing components was small. Therefore, the variation of tracers and the difference of mixing components should be considered when hydrograph separation was applied in the basin.

  10. Photon and Water Mediated Sulfur Oxide and Acid Chemistry in the Atmosphere of Venus

    Science.gov (United States)

    Kroll, Jay A.; Vaida, Veronica

    2014-06-01

    Sulfur compounds have been observed in the atmospheres of a number of planetary bodies in our solar system including Venus, Earth, Mars, Io, Europa, and Callisto. The global cloud cover on Venus located at an altitude between 50 and 80 kilometers is composed primarily of sulfuric acid (H_2SO_4) and water. Planetary photochemical models have attempted to explain observations of sulfuric acid and sulfur oxides with significant discrepancies remaining between models and observation. In particular, high SO_2 mixing ratios are observed above 90 km which exceed model predictions by orders of magnitude. Work recently done in the Vaida lab has shown red light can drive photochemistry through overtone pumping for acids like H_2SO_4 and has been successful in explaining much of the sulfur chemistry in Earth's atmosphere. Water can have a number of interesting effects such as catalysis, suppression, and anti-catalysis of thermal and photochemical processes. We investigate the role of water complexes in the hydration of sulfur oxides and dehydration of sulfur acids and present spectroscopic studies to document such effects. We investigate these reactions using FTIR and UV/Vis spectroscopy and will report on our findings.

  11. Plasma Discharges in Gas Bubbles in Liquid Water: Breakdown Mechanisms and Resultant Chemistry

    Science.gov (United States)

    Gucker, Sarah M. N.

    The use of atmospheric pressure plasmas in gases and liquids for purification of liquids has been investigated by numerous researchers, and is highly attractive due to their strong potential as a disinfectant and sterilizer. However, the fundamental understanding of plasma production in liquid water is still limited. Despite the decades of study dedicated to electrical discharges in liquids, many physical aspects of liquids, such as the high inhomogeneity of liquids, complicate analyses. For example, the complex nonlinearities of the fluid have intricate effects on the electric field of the propagating streamer. Additionally, the liquid material itself can vaporize, leading to discontinuous liquid-vapor boundaries. Both can and do often lead to notable hydrodynamic effects. The chemistry of these high voltage discharges on liquid media can have circular effects, with the produced species having influence on future discharges. Two notable examples include an increase in liquid conductivity via charged species production, which affects the discharge. A second, more complicated scenario seen in some liquids (such as water) is the doubling or tripling of molecular density for a few molecule layers around a high voltage electrode. These complexities require technological advancements in optical diagnostics that have only recently come into being. This dissertation investigates several aspects of electrical discharges in gas bubbles in liquids. Two primary experimental configurations are investigated: the first allows for single bubble analysis through the use of an acoustic trap. Electrodes may be brought in around the bubble to allow for plasma formation without physically touching the bubble. The second experiment investigates the resulting liquid phase chemistry that is driven by the discharge. This is done through a dielectric barrier discharge with a central high voltage surrounded by a quartz discharge tube with a coil ground electrode on the outside. The plasma

  12. Interpreting Linkages among Landscape, Water Chemistry, and Diatom Communities to Better Understand Subarctic Paleoenvironmental Records

    Science.gov (United States)

    Shinneman, A.; Hobbs, W.; Edlund, M.; Umbanhowar, C. E.; Camill, P.; Geiss, C. E.

    2010-12-01

    Arctic ecosystem response to climate warming will likely be complex, with important linkages among terrestrial, wetland, and aquatic systems set within the context of geologically unique landscapes. Ecosystem responses to warming include: increased lake productivity, permafrost thaw, shrub expansion, and northward shifts in subarctic tree line. There have been many studies on freshwater aquatic responses to climate change in the Arctic, but few consider the role of the terrestrial landscape. As part of a three-year project to study the Holocene history of lakes and landscapes and their response to climate, we undertook a hydrobiological survey along the northern Manitoba boreal forest-tundra ecotone, with the aim of linking lake water chemistry with surrounding landscape and with the algal (diatom and chrysophyte) community composition in the lakes. Fossil algal assemblages from sediment cores can be better interpreted in terms of complex relationships between climate change, landscape change, and lake response if an understanding of modern linkages is developed. Using this modern study to develop quantitative calibration, sediment cores were used to focus on landscape-level biogeochemical changes in these systems at multiple time scales over the past 8,000 years. Forty-five lakes across the boreal-tundra transition were sampled for diatoms and physico-chemistry in 2008-2009 and their watersheds characterized using GIS. Diatoms were collected from the surface (top 1-cm) of a sediment core. Water quality measures included nutrients, anions and cations, pH, conductivity, Secchi depth, and dissolved carbon. Landscape variables including watershed area, watershed to lake area ratios, wetland area within 100 m of lake shore and percent cover of different vegetation types were calculated using GIS with on the ground verification. Primary gradients among the lakes are related to pH and water clarity. Among the landscape variables, distance to treeline, slope, wetland

  13. Results of water corrosion in static cell tests representing multi-metal assemblies in the hydraulic circuits of Tore supra

    International Nuclear Information System (INIS)

    Following experiences obtained with steam generator tubes of nuclear power plants, a cooling water quality of AVT (all volatile treatment) has been defined based on demineralised water with adjustment of the pH value to about 9.0/7.0 (25 C/200 C) by addiction of ammoniac, and hydrazine in order to absorb oxygen dissolved in water. At that time, a simplified water corrosion test program has been performed using static (no circulation) test cell samples made of above mentioned TS metal combinations. All test cell samples, prepared and filled with AVT water, were performed at 280 C and 65 bars in an autoclave during 3000 hours. The test cell water temperature has been chosen to be sufficient above the TS component working temperature, in order to accelerate an eventual corrosion process. Generally all above mentioned metal combinations survived the test campaign without stress corrosion cracking, with the exception of the memory metal junction (creep in Cu) and the bellows made of St-St 316L and Inconel 625 while 316 Ti bellows survived. In contrary to the vacuum brazed Cu-LSTP to St-St samples, some of flame brazed Cu to St-St samples failed either in the braze joint or in the copper structure itself. For comparison, a spot weld of an inflated 316L panel sample, filled voluntary with a caustic solution of pH 11.5 (25 C), failed after 90 h of testing (intergranular cracking at the spot weld), while an identical sample containing AVT water of pH 9.0 (25 C) survived without damage. The results of these tests, performed during 1986 and 1997, have never been published and therefore are presented more in detail in this paper since corrosion in hydraulic circuits is also an issue of ITER. Up to day, the TS cooling water plant operates with an above mentioned water treatment and no water leaks have been detected on in-vessel components originating from water corrosion at high temperature and high pressure. (orig.)

  14. Water chemistry in Kuji river. Its spatial and seasonal variations in major ions and organic substances

    Energy Technology Data Exchange (ETDEWEB)

    Niina, Toshiaki; Matsunaga, Takeshi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-02-01

    As a basic research with a aim to clarify the migration behavior of radionuclides in rivers, the characteristics of dissolved ions and organic substances in river water, which characteristics may affect the behavior, was investigated. The investigation was carried out for the Kuji river in the northern Kanto district (Japan) comprising four sampling campaigns in 1994 for 10 locations from the upstream to the downstream. Concentrations of major ions, iron and manganese species and organic substances were analyzed in laboratory. Values of temperature of the water, pH, conductivity, dissolved oxygen were measured in the field. This investigation was conducted mainly under low water flow conditions of the river, while a limited number of campaigns were under high flow conditions due to precipitation events. The concentrations of major inorganic ions increased steadily toward the down-stream, resulting in approximately two times increase for the traveling distance of 100 km. They showed a seasonal variation that they were highest in the spring and lowest in the autumn when there were most concentrated precipitation events in a year. The constituents were mainly Na{sup +}, Ca{sup 2+}, SO{sub 4}{sup 2-} and HCO{sub 3}{sup -}, and were similar for every sampling locations and seasons. Concentrations of dissolved organic substances (carbon compounds) were lowest in the upstream and increased about twice in the downstream as well as major inorganic ions. Their level was 1-3 mg/l, which can be ranked as relatively lower in general values for fresh water environments. They were highest in the spring (average over the locations: 2.2 mg/l) and lowest in the autumn (1.3 mg/l) and also in the winter (1.3 mg/l). These results will be useful as a basic understanding of spatial and seasonal variations of river water chemistry, especially related to the organic substances which can bind with radionuclides to make a mobile complex. (author).

  15. Water chemistry in Kuji river. Its spatial and seasonal variations in major ions and organic substances

    International Nuclear Information System (INIS)

    As a basic research with a aim to clarify the migration behavior of radionuclides in rivers, the characteristics of dissolved ions and organic substances in river water, which characteristics may affect the behavior, was investigated. The investigation was carried out for the Kuji river in the northern Kanto district (Japan) comprising four sampling campaigns in 1994 for 10 locations from the upstream to the downstream. Concentrations of major ions, iron and manganese species and organic substances were analyzed in laboratory. Values of temperature of the water, pH, conductivity, dissolved oxygen were measured in the field. This investigation was conducted mainly under low water flow conditions of the river, while a limited number of campaigns were under high flow conditions due to precipitation events. The concentrations of major inorganic ions increased steadily toward the down-stream, resulting in approximately two times increase for the traveling distance of 100 km. They showed a seasonal variation that they were highest in the spring and lowest in the autumn when there were most concentrated precipitation events in a year. The constituents were mainly Na+, Ca2+, SO42- and HCO3-, and were similar for every sampling locations and seasons. Concentrations of dissolved organic substances (carbon compounds) were lowest in the upstream and increased about twice in the downstream as well as major inorganic ions. Their level was 1-3 mg/l, which can be ranked as relatively lower in general values for fresh water environments. They were highest in the spring (average over the locations: 2.2 mg/l) and lowest in the autumn (1.3 mg/l) and also in the winter (1.3 mg/l). These results will be useful as a basic understanding of spatial and seasonal variations of river water chemistry, especially related to the organic substances which can bind with radionuclides to make a mobile complex. (author)

  16. Are fragment-based quantum chemistry methods applicable to medium-sized water clusters?

    Science.gov (United States)

    Yuan, Dandan; Shen, Xiaoling; Li, Wei; Li, Shuhua

    2016-06-28

    Fragment-based quantum chemistry methods are either based on the many-body expansion or the inclusion-exclusion principle. To compare the applicability of these two categories of methods, we have systematically evaluated the performance of the generalized energy based fragmentation (GEBF) method (J. Phys. Chem. A, 2007, 111, 2193) and the electrostatically embedded many-body (EE-MB) method (J. Chem. Theory Comput., 2007, 3, 46) for medium-sized water clusters (H2O)n (n = 10, 20, 30). Our calculations demonstrate that the GEBF method provides uniformly accurate ground-state energies for 10 low-energy isomers of three water clusters under study at a series of theory levels, while the EE-MB method (with one water molecule as a fragment and without using the cutoff distance) shows a poor convergence for (H2O)20 and (H2O)30 when the basis set contains diffuse functions. Our analysis shows that the neglect of the basis set superposition error for each subsystem has little effect on the accuracy of the GEBF method, but leads to much less accurate results for the EE-MB method. The accuracy of the EE-MB method can be dramatically improved by using an appropriate cutoff distance and using two water molecules as a fragment. For (H2O)30, the average deviation of the EE-MB method truncated up to the three-body level calculated using this strategy (relative to the conventional energies) is about 0.003 hartree at the M06-2X/6-311++G** level, while the deviation of the GEBF method with a similar computational cost is less than 0.001 hartree. The GEBF method is demonstrated to be applicable for electronic structure calculations of water clusters at any basis set. PMID:27263629

  17. Calculation of transport coefficients of air-water vapor mixtures thermal plasmas used in circuit breakers

    Directory of Open Access Journals (Sweden)

    KOHIO Niéssan

    2014-12-01

    Full Text Available In this paper we calculate the transport coefficients of plasmas formed by air and water vapor mixtures. The calculation, which assume local thermodynamic equilibrium (LTE are performed in the temperature range from 500 to 12000 K. We use the Gibbs free energy minimization method to determine the equilibrium composition of the plasmas, which is necessary to calculate the transport coefficients. We use the Chapman-Enskog method to calculate the transport coefficients. The results are presented and discussed according to the rate of water vapor. The results of the total thermal conductivity and electrical conductivity show in particular that the increasing of the rate of water vapor in air can be interesting for power cut. This could be improve the performance of plasma during current breaking in air contaminate by the water vapor.

  18. Effect of water chemistry on stress corrosion cracking of structural materials in high temperature water

    International Nuclear Information System (INIS)

    The effect of environmental factors, including concentration of chloride, content of dissolved oxygen (DO) and temperature, on the susceptibility to stress corrosion cracking (SCC) of type 304, 316Ti stainless steels (s.s.) and A533B pressure vessel steel in high temperature water (HTW) has been investigated using slow strain rate tests (SSRT) and/or U-bends, complemented by electrochemical measurements and AES analyses of the surface films. Increasing chloride concentration resulted in an increase in the susceptibility to SCC. The content of DO was a predominant factor affecting the susceptibility to SCC of A533B. The critical potential and DO content for the occurrence of SCC of 316Ti s.s. in HTW at 300 deg. C was experimentally estimated. (author)

  19. Industrial cleaning with Qlean Water : a case study of printed circuit boards

    OpenAIRE

    Lindahl, Mattias; Svensson, Niclas; Svensson, Bo; Sundin, Erik

    2013-01-01

    Many manufacturing companies are looking for ways to substitute environmentally problematic cleaning methods for surface treatments with more environmentally friendly ones. In this paper, one potential solution is described. The Qlean method, based on cleaning with highly pure water (in this paper defined as Qlean Water), is a novel cleaning method. This method, now utilized at one plant at a leading major international electronic company, has substituted previous chemical-based methods for c...

  20. Effects of materials and water chemistry factors on FAC rate of carbon steels

    International Nuclear Information System (INIS)

    Pipe wall thinning due to flow accelerated corrosion (FAC) is one of the most important degradation modes which can take place in nuclear power plants. Potential area of FAC is widespread in piping systems and probability of pipe failure due to FAC is relatively high compared to other causes. FAC is a complex phenomenon, where mass transfer under turbulent flow, chemical reactions at interfaces, and mass diffusion in oxide scales cooperatively or competitively interact. Among a number of influencing parameters for FAC rate, this paper focuses on Cr in carbon steels and pH of water. pH is the primary water chemistry parameter to manage FAC susceptibility of the whole piping systems. Small amount of Cr has a significant effect for improving resistance of the carbon steels to FAC. This fact offers an effective countermeasure for FAC mitigation by using Cr modified steels, but, at the same time, the Cr dependence could give difficult problems, when we manage pipe wall thinning with thickness inspections. In a procedure to sample piping lines and locations of thickness measurement, we may need to take into account Cr content of the pipes picked up for the inspection. We also need to pay attention on difference in Cr content between pipes and weld filler metal, even though the absolute Cr levels of the both steels are minor. In the cases that Cr content of weld metal is lower than that of pipe materials, circumferential grooving may form along the weld. Basically, effects of those material and water chemistry factors can be attributed to oxide scale properties, such as solubility to water, porosity, semiconductor property, etc. This paper briefly reviews experimental data of Cr, Ni, Cu effects and of pH effects, including both widely recognized 'historical' data and recent data on combined effects of Cr content and pH obtained by the authors. Characteristics of oxide scales formed in the FAC experiments, such as defect characteristics and Cr enrichment distribution, and

  1. Mineralogy and geochemistry of efflorescent minerals on mine tailings and their potential impact on water chemistry.

    Science.gov (United States)

    Grover, B P C; Johnson, R H; Billing, D G; Weiersbye, I M G; Tutu, H

    2016-04-01

    In the gold mining Witwatersrand Basin of South Africa, efflorescent mineral crusts are a common occurrence on and nearby tailings dumps during the dry season. The crusts are readily soluble and generate acidic, metal- and sulphate-rich solutions on dissolution. In this study, the metal content of efflorescent crusts at an abandoned gold mine tailings dump was used to characterise surface and groundwater discharges from the site. Geochemical modelling of the pH of the solution resulting from the dissolution of the crusts was used to better understand the crusts' potential impact on water chemistry. The study involved two approaches: (i) conducting leaching experiments on oxidised and unoxidised tailings using artificial rainwater and dilute sulphuric acid and correlating the composition of crusts to these leachates and (ii) modelling the dissolution of the crusts in order to gain insight into their mineralogy and their potential impact on receiving waters. The findings suggested that there were two chemically distinct discharges from the site, namely an aluminium- and magnesium-rich surface water plume and an iron-rich groundwater plume. The first plume was observed to originate from the oxidised tailings following leaching with rainwater while the second plume originated from the underlying unoxidised tailings with leaching by sulphuric acid. Both groups of minerals forming from the respective plumes were found to significantly lower the pH of the receiving water with simulations of their dissolution found to be within 0.2 pH units of experimental values. It was observed that metals in a low abundance within the crust (for example, iron) had a stronger influence on the pH of the resulting solutions than metals in a greater abundance (aluminium or magnesium). Techniques such as powder X-ray diffraction (PXRD) and in situ mineral determination techniques such as remote sensing can effectively determine the dominant mineralogy. However, the minerals or metals

  2. Multivariate Statistical Analysis of Water Chemistry in Evaluating the Origin of Contamination in Many Devils Wash, Shiprock, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-12-31

    This report evaluates the chemistry of seep water occurring in three desert drainages near Shiprock, New Mexico: Many Devils Wash, Salt Creek Wash, and Eagle Nest Arroyo. Through the use of geochemical plotting tools and multivariate statistical analysis techniques, analytical results of samples collected from the three drainages are compared with the groundwater chemistry at a former uranium mill in the Shiprock area (the Shiprock site), managed by the U.S. Department of Energy Office of Legacy Management. The objective of this study was to determine, based on the water chemistry of the samples, if statistically significant patterns or groupings are apparent between the sample populations and, if so, whether there are any reasonable explanations for those groupings.

  3. Derivatization Ion Chromatography for the Determination of Monoethanolamine in Presence of Hydrazine in PHWR Steam-Water Circuits

    Directory of Open Access Journals (Sweden)

    Ayushi D.

    2011-01-01

    Full Text Available A simple, rapid and accurate method for the determination of monoethanolamine (MEA in PHWR steam-water circuits has been developed. MEA is added in the feed water to provide protection against corrosion while hydrazine is added to scavenge dissolved oxygen. The quantitative determination of MEA in presence of hydrazine was accomplished using derivatization ion chromatography with conductometric detection in nonsuppressed mode. A Metrosep cation 1-2 analytical column and a Metrosep cartridge were used for cation separation. A mixture of 4 mM tartaric acid, 20% acetone and 0.05 mM HNO3 was used as eluent. Acetone in the mobile phase leads to the formation of different derivatives with MEA and hydrazine. The interferences due Na+ and NH4 + were eliminated by adopting a simple pretreatment procedure employing OnGuard-H cartridge. The limit of detection limit of MEA was 0.1 μg mL−1 and the relative standard deviation was 2% for the overall method. The recovery of MEA added was in the range 95%–102%. The method was applied to the determination of MEA in steam generator water samples.

  4. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    International Nuclear Information System (INIS)

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for 60Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.)

  5. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for {sup 60}Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.) 127 refs.

  6. Development of evaluation tool for radiation dose rate distribution in PCV of Hamaoka BWR plants based on water chemistry

    International Nuclear Information System (INIS)

    We have developed an evaluation tool for the radiation dose rate distribution of the work areas in the primary containment vessel (PCV) of Units 3, 4 (BWR5) and 5 (ABWR) at Hamaoka NPS. This tool has been constructed based on the transport behavior of radioactive corrosion products in the primary cooling water of BWR. This tool can be used to evaluate quantitatively the effects of the dose reduction methods by water chemistry control or radiation management. It is composed of two calculation codes; water chemistry code (ACTTUBE) and radiation dose rate code (RADTUBE). ACTTUBE calculates the piping dose rates based on the mass balance of corrosion products, 6 kinds of metal and 5 kinds of radionuclide, among the parts of primary cooling water, such as reactor water, feed water, fuel rod surface and out-of-core piping surface. RADTUBE calculates the dose rate distribution based on the radiation shielding calculation from a calculation result of ACTTUBE. Additionally, this tool has a visualization function of calculated radiation dose rate distribution in the PCV by using a wireless controller and 3D glasses/monitor in order to improve user convenience. The accuracy of the tool's calculation results was evaluated using the water chemistry data and radiation dose rate data of the Hamaoka plants. As a result, it was confirmed that this tool had sufficient accuracy to be used in the evaluation of radiation dose rates for the radiation management of actual plants. (author)

  7. Effect of water chemistry on crud deposition behavior on heated zircaloy-4 surface in simulated PWR primary water

    International Nuclear Information System (INIS)

    Japanese PWR utilities desire to employ long-term fuel cycle and high burn-up operations, in order to increase the plant utilization. Accordance with plant aging, employing the long-term fuel cycle and high burn-up operations, amounts of crud deposition on fuel cladding surface will be increased. The large amounts of crud deposition on the fuel cladding has led to an increase of the field radiation build-up in the primary coolant system and become a root cause of axial offset anomalies (AOA). Japanese PWRs has not been experienced in AOA, on the other hand, crud deposition on the PWR fuel cladding surface would become significant issue in Japanese PWRs. In order to clarify the contribution factors of the crud deposition related to the water chemistry, the effects of boron, nickel concentrations and nickel/iron ratio in the test solution on the crud deposition were investigated in a simulated Japanese PWR fuel cycle chemistry (1800ppm as B + 3.4ppm as Li + 25ml-STP/kg-H2O, 1200ppm as B + 2.2ppm as Li + 25ml-STP/kg-H2O, 350ppm as B + 2.2ppm as Li + 25ml-STP/kg-H2O solution) at 325oC under sub-cooled boiling and non-irradiated condition. The corrosion resistance of zircaloy-4 was also investigated in the simulated Japanese PWR primary chemistry. From the test results, it was revealed that the crud layer composed of NiFe2O4 and NiO was formed on the surface of zircaloy-4 fuel cladding. The oxide was easy to be formed on the heated surface of the fuel cladding. The amounts of deposited crud layer increased with increase of boron, nickel concentrations, pHT and nickel/iron ratio in the test solution. The formation of nickel borate (Ni2FeBO5) was not identified, however, boron was detected in the crud layer. Nickel and boron contents in the crud layer were increased with increase of nickel concentration in the test solution. The corrosion resistance of Zr-4 was maintained in the test condition. (author)

  8. Organic geochemistry and pore water chemistry of sediments from Mangrove Lake, Bermuda

    Science.gov (United States)

    Hatcher, P.G.; Simoneit, B.R.T.; MacKenzie, F.T.; Neumann, A.C.; Thorstenson, D.C.; Gerchakov, S.M.

    1982-01-01

    Mangrove Lake, Bermuda, is a small coastal, brackish-water lake that has accumulated 14 m of banded, gelatinous, sapropelic sediments in less than 104 yr. Stratigraphic evidence indicates that Mangrove Lake's sedimentary environment has undergone three major depositional changes (peat, freshwater gel, brackish-water gel) as a result of sea level changes. The deposits were examined geochemically in an effort to delineate sedimentological and diagenetic changes. Gas and pore water studies include measurements of sulfides, ammonia, methane, nitrogen gas, calcium, magnesium, chloride, alkalinity, and pH. Results indicate that sulfate reduction is complete, and some evidence is presented for bacterial denitrification and metal sulfide precipitation. The organic-rich sapropel is predominantly algal in origin, composed mostly of carbohydrates and insoluble macromolecular organic matter called humin with minor amounts of proteins, lipids, and humic acids. Carbohydrates and proteins undergo hydrolysis with depth in the marine sapropel but tend to be preserved in the freshwater sapropel. The humin, which has a predominantly aliphatic structure, increases linearly with depth and composes the greatest fraction of the organic matter. Humic acids are minor components and are more like polysaccharides than typical marine humic acids. Fatty acid distributions reveal that the lipids are of an algal and/or terrestrial plant source. Normal alkanes with a total concentration of 75 ppm exhibit two distribution maxima. One is centered about n-C22 with no odd/even predominance, suggestive of a degraded algal source. The other is centered at n-C31 with a distinct odd/even predominance indicative of a vascular plant origin. Stratigraphic changes in the sediment correlate to observed changes in the gas and pore water chemistry and the organic geochemistry. ?? 1982.

  9. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals

    Science.gov (United States)

    Grant, Rachel A.; Halliday, Tim; Balderer, Werner P.; Leuenberger, Fanny; Newcomer, Michelle; Cyr, Gary; Freund, Friedemann T.

    2011-01-01

    Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth’s crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O− in a matrix of O2−. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth’s surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L’Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals. PMID:21776211

  10. An Introduction to Boiler Water Chemistry for the Marine Engineer: A Text of Audio-Tutorial Instruction.

    Science.gov (United States)

    Schlenker, Richard M.; And Others

    Presented is a manuscript for an introductory boiler water chemistry course for marine engineer education. The course is modular, self-paced, audio-tutorial, contract graded and combined lecture-laboratory instructed. Lectures are presented to students individually via audio-tapes and 35 mm slides. The course consists of a total of 17 modules -…

  11. Ecology of subtropical, shallow water environments: chemistry of copper and chlorine introduced into marine systems during energy production

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    During the last three contract years, we have been involved in the study of the chemistry of the copper binding compounds occurring in coastal seawater. Initially our efforts were oriented towards the study of the complexing capacity of waters collected at various locations in the Miami, Florida area. Our study then shifted towards the concentration and the elucidation of these chelators.

  12. Enhanced Control of PWR Primary Coolant Water Chemistry Using Selective Separation Systems for Recovery and Recycle of Enriched Boric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Ken Czerwinski; Charels Yeamans; Don Olander; Kenneth Raymond; Norman Schroeder; Thomas Robison; Bryan Carlson; Barbara Smit; Pat Robinson

    2006-02-28

    The objective of this project is to develop systems that will allow for increased nuclear energy production through the use of enriched fuels. The developed systems will allow for the efficient and selective recover of selected isotopes that are additives to power water reactors' primary coolant chemistry for suppression of corrosion attack on reactor materials.

  13. Ecology of subtropical, shallow water environments: chemistry of copper and chlorine introduced into marine systems during energy production

    International Nuclear Information System (INIS)

    During the last three contract years, we have been involved in the study of the chemistry of the copper binding compounds occurring in coastal seawater. Initially our efforts were oriented towards the study of the complexing capacity of waters collected at various locations in the Miami, Florida area. Our study then shifted towards the concentration and the elucidation of these chelators

  14. The application of high pH operation to the secondary water chemistry at Genkai Nuclear Power Station

    International Nuclear Information System (INIS)

    PWR plants have made efforts to maintain the long-term integrity of the steam generators (SG) by reducing the amount of corrosion products entering the secondary side of the SG. Iron entered the SG can cause several problems: degraded heat conductivity of the SG tubes in locations where iron is deposited, water level oscillations in the SG due to tube support plate hole blockage, and initiation and propagation of inter-granular attacks (IGA) and stress corrosion cracking (SCC). One of the most effective measures, high all-volatile treatment (AVT) chemistry has been applied to actual plants to reduce the flow-accelerated corrosion (FAC) coming from the carbon steel piping. The secondary water chemistry at Genkai NPS 1 and 2 changed, from the Low AVT chemistry to the High AVT chemistry, in November 2006. In this paper, we will describe the results of experiments in applying the use of High pH water in the secondary water system at Genkai NPS. (author)

  15. Seasonal effects on ground water chemistry of the Ouachita Mountains. National Uranium Resource Evaluation Program

    International Nuclear Information System (INIS)

    Samples from 13 ground water sites (10 springs and 3 wells) in the Ouachita Mountains were collected nine times during a 16-month period. Daily sampling of six sites was carried out over an 11-day period, with rain during this period. Finally, hourly sampling was conducted at a single site over a 7-hour period. The samples were analyzed for pH, conductivity, temperature, total alkalinity, nitrate, ammonia, sulfate, phosphate, chloride, silica, Na, K, Li, Ca, Mg, Sr, Ba, Fe, Mn, Zn, Cu, Co, Ni, Pb, Hg, Br, F, V, Al, Dy, and U. Despite the dry season during late summer, and wet seasons during late spring and late fall in the Ouachita Mountain region, there was no significant change in the ground water chemistry with season. Likewise, there was no significant change due to rain storm events (daily sampling) or hourly sampling. The report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation. 9 figures, 19 tables

  16. Continuous high-temperature surveillance instrumentation for Dresden-2 hydrogen water chemistry program

    International Nuclear Information System (INIS)

    The objective of this program (under EPRI Contract RP1930-11) is to install and operate a high-temperature surveillance instrumentation system capable of monitoring the length of cracks in boiling water reactor (BWR) piping during plant operation. The ability to measure crack growth in BWR power plant piping welds is important to rapidly identify the effectiveness of repairs (such as the Hydrogen Water Chemistry Program). The feasibility of a system capable of continuous ultrasonic instrumentation at 6000F (2880C) was successfully demonstrated at the Dresden-2 suction line known as N1B. This intergranular stress corrosion cracking (IGSCC) surveillance instrumentation is sound in principal, because it survived on N1B for a time period of more than nine months from April 1985 to January 1986 (the last time data were recorded). The redesigned low-profile transducer system used for this system operated successfully for the same nine-month time period. This low profile transducer fits in the two-inch space normally occupied by insulation. As a result of poor routing of the coaxial cables running from the low-profile transducer to the electrical feed-throughs between the drywell and containment, these cables melted. Other instrument cables nearby were not damaged

  17. Interactions between hydrology and water chemistry shape bacterioplankton biogeography across boreal freshwater networks.

    Science.gov (United States)

    Niño-García, Juan Pablo; Ruiz-González, Clara; Del Giorgio, Paul A

    2016-07-01

    Disentangling the mechanisms shaping bacterioplankton communities across freshwater ecosystems requires considering a hydrologic dimension that can influence both dispersal and local sorting, but how the environment and hydrology interact to shape the biogeography of freshwater bacterioplankton over large spatial scales remains unexplored. Using Illumina sequencing of the 16S ribosomal RNA gene, we investigate the large-scale spatial patterns of bacterioplankton across 386 freshwater systems from seven distinct regions in boreal Québec. We show that both hydrology and local water chemistry (mostly pH) interact to shape a sequential structuring of communities from highly diverse assemblages in headwater streams toward larger rivers and lakes dominated by fewer taxa. Increases in water residence time along the hydrologic continuum were accompanied by major losses of bacterial richness and by an increased differentiation of communities driven by local conditions (pH and other related variables). This suggests that hydrology and network position modulate the relative role of environmental sorting and mass effects on community assembly by determining both the time frame for bacterial growth and the composition of the immigrant pool. The apparent low dispersal limitation (that is, the lack of influence of geographic distance on the spatial patterns observed at the taxonomic resolution used) suggests that these boreal bacterioplankton communities derive from a shared bacterial pool that enters the networks through the smallest streams, largely dominated by mass effects, and that is increasingly subjected to local sorting of species during transit along the hydrologic continuum. PMID:26849312

  18. REDOX CHEMISTRY OF MOLYBDENUM IN NATURAL WATERS AND ITS INVOLVEMENT IN BIOLOGICAL EVOLUTION

    Directory of Open Access Journals (Sweden)

    DeliWang

    2012-12-01

    Full Text Available The transition element molybdenum (Mo possesses diverse valances (+II to +VI, and is involved in forming cofactors in more than 60 enzymes in biology. Redox switching of the element in these enzymes catalyzes a series of metabolic reactions in both prokaryotes and eukaryotes, and the element therefore plays a fundamental role in the global carbon, nitrogen, and sulfur cycling. In the present oxygenated waters, oxidized Mo(VI predominates thermodynamically, whilst reduced Mo species are mainly confined within specific niches including cytoplasm. Only recently has the reduced Mo(V been separated from Mo(VI in sulfidic mats and even in some reducing waters. Given the presence of reduced Mo(V in contemporary anaerobic habitats, it seems that reduced Mo species were present in the ancient reducing ocean (probably under both ferrigenous and sulfidic conditions, prompting the involvement of Mo in enzymes including nitrogenase and nitrate reductase. During the global transition to oxic conditions, reduced Mo species were constrained to specific anaerobic habitats, and efficient uptake systems of oxidized Mo(VI became a selective advantage both for prokaryotic and eukaryotic cells. Some prokaryotes are still able to directly utilize reduced Mo if any exists in ambient environments. In total, this mini-review describes the redox chemistry and biogeochemistry of Mo over the Earth’s history.

  19. Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing.

    Science.gov (United States)

    Holmquist, H; Schellenberger, S; van der Veen, I; Peters, G M; Leonards, P E G; Cousins, I T

    2016-05-01

    Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (includes dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regards to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellence of non-fluorinated alternatives. It also shows that for all alternatives, impurities and/or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the

  20. Water chemistry and its correlation with Algae at Kawai of Kaghan Valley

    International Nuclear Information System (INIS)

    The study of water chemistry and correlation with Algae at Kawai from Kunhar River was carried out in June 2000 to October 2001. Water samples collected by Nansen bottles for studying the physico-chemical features using standard methods (APHA, 1985), some necessary parametres were recorded at the time of collection on collection spot. The water samples were brought in laboratory for further analyses. The physico-chemical parameters used in the study were temperature, pH, free carbondioxide, dissolved oxygen, ammonia nitrogen, humidity, total hardness, orthophosphate etc. 38 physico-chemical parametres were obtained. The biological samples were collected by phytoplankton net, slide cover, forceps, tooth brush, pipet, knife, hand picking etc. from different zones like mixed reactors, too old branches, basins, pools, dead zones at the back of tree, groynes, stones etc. The biological samples were preserved in 4% formaline solution. The biological samples were examined and found to contain the total number of 123 Algal species belonging to 61 genera of 7 Algal groups. Cyanophyceae (34 species 27.6% belonging to 17 genera), Chlorophyceae (32 species 26% belonging to 20 genera), Bacillariophyceae (45 species 36.6% belonging to 17 genera), Chrysophyceae (2 species 1.63% belonging to 1 genus), Xanthophyceae (2 species 1.63% belonging to 2 genera), Euglenophyceae (5 species 4.1% belonging to 3 genera), Charophyceae 3 species 2.44% belonging to 1 genus) were recorded. Water is rich in primary productivity and fish production so the several fish species are commonly found due to rich of Algal species. The abundance of Algal species as a result the ratio of DO was high through out the year, which is beneficial for aquatic organism fish and fauna etc. The water was alkaline recorded. While different species have various value from point of importance like some species are useful for medicine, nitrogen fixing, vitamins, toxic, very interesting, delicious food for aquatic

  1. Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process

    International Nuclear Information System (INIS)

    An effective and benign process for copper and lead recovery from waste printed circuit boards (PCBs) was developed. In the process, the PCBs was pre-treated in supercritical water, then subjected to electrokinetic (EK) process. Experimental results showed that supercritical water oxidation (SCWO) process was strong enough to decompose the organic compounds of PCBs, and XRD spectra indicated that copper and lead were oxidized into CuO, Cu2O and β-PbO2 in the process. The optimum SCWO treatment conditions were 60 min, 713 K, 30 MPa, and EK treatment time, constant current density were 11 h, 20 mA cm-2, respectively. The recovery percentages of copper and lead under optimum SCWO + EK treatment conditions were around 84.2% and 89.4%, respectively. In the optimized EK treatment, 74% of Cu was recovered as a deposit on the cathode with a purity of 97.6%, while Pb was recovered as concentrated solutions in either anode (23.1%) or cathode (66.3%) compartments but little was deposited on the electrodes. It is believed that the process is effective and practical for Cu and Pb recovery from waste electric and electronic equipments.

  2. Variability of Water Chemistry in Tundra Lakes, Petuniabukta Coast, Central Spitsbergen, Svalbard

    Directory of Open Access Journals (Sweden)

    Małgorzata Mazurek

    2012-01-01

    Full Text Available Samples of water from small tundra lakes located on raised marine terraces on the eastern coast of Petuniabukta (Ebbadalen, Central Spitsbergen were examined to assess the changes in water chemistry that had occurred during the summer seasons of 2001–2003 and 2006. The unique environmental conditions of the study region include the predominance of sedimentary carbonate and sulphate rocks, low precipitation values, and an active permafrost layer with a maximum thickness of 1.2 m. The average specific electric conductivity (EC values for the three summer seasons in the four lakes ranged from 242 to 398 μS cm−1. The highest EC values were observed when the air temperature decreased and an ice cover formed (cryochemical effects. The ion composition was dominated by calcium (50.7 to 86.6%, bicarbonates (39.5 to 86.4%, and sulphate anions. The high concentrations of HCO3−, SO42−, and Ca2+ ions were attributed to the composition of the bedrock, which mainly consists of gypsum and anhydrite. The average proportion of marine components in the total load found in the Ebbadalen tundra lake waters was estimated to be 8.1%. Precipitation supplies sulphates (as much as 69–81% and chlorides (14–36% of nonsea origin. The chief source of these compounds may be contamination from the town of Longyearbyen. Most ions originate in the crust, the active layer of permafrost, but some are atmospheric in origin and are either transported or generated in biochemical processes. The concentrations of most components tend to increase during the summer months, reaching a maximum during freezing and partially precipitating onto the bottom sediments.

  3. Application, chemistry, and environmental implications of contaminant-immobilization amendments on agricultural soil and water quality.

    Science.gov (United States)

    Udeigwe, Theophilus K; Eze, Peter N; Teboh, Jasper M; Stietiya, Mohammed H

    2011-01-01

    Contaminants such as nitrogen (N), phosphorus (P), dissolved organic carbon (DOC), arsenic (As), heavy metals, and infectious pathogens are often associated with agricultural systems. Various soil and water remediation techniques including the use of chemical amendments have been employed to reduce the risks associated with these contaminants. This paper reviews the use of chemical amendments for immobilizing principal agricultural contaminants, the chemistry of contaminant immobilization, and the environmental consequences associated with the use of these chemical products. The commonly used chemical amendments were grouped into aluminum-, calcium-, and iron-containing products. Other products of interest include phosphorus-containing compounds and silicate clays. Mechanisms of contaminant immobilization could include one or a combination of the following: surface precipitation, adsorption to mineral surfaces (ion exchange and formation of stable complexes), precipitation as salts, and co-precipitation. The reaction pH, redox potential, clay minerals, and organic matter are potential factors that could control contaminant-immobilization processes. Reviews of potential environmental implications revealed that undesirable substances such as trace elements, fluoride, sulfate, total dissolved solids, as well as radioactive materials associated with some industrial wastes used as amendment could be leached to ground water or lost through runoff to receiving water bodies. The acidity or alkalinity associated with some of the industrial-waste amendments could also constitute a substantial environmental hazard. Chemical amendments could introduce elements capable of inducing or affecting the activities of certain lithotrophic microbes that could influence vital geochemical processes such as mineral dissolution and formation, weathering, and organic matter mineralization. PMID:20832118

  4. Environmental water monitoring by capillary electrophoresis and result comparison with solvent chemistry techniques.

    Science.gov (United States)

    Sirén, Heli; Väntsi, Sirpa

    2002-05-24

    The aim of this work was to determine inorganic ions from natural waters by capillary electrophoresis (CE) and to compare the results obtained with those measured with conventional solvent chemistry techniques. The project was part of a larger CE study, during which we measured inorganic ions from some lake and river systems and groundwaters in Southern Finland. Results obtained from contaminated Finnish waters were compared with samples from the River Rhine in the Düsseldorf area. Two CE methods were used for analysis: one for determination of chloride, sulfate, nitrite and nitrate at pH 7.7 and the other for ammonium, potassium, calcium, sodium and magnesium at pH 3.6, both methods using identification based on indirect UV detection. Two separation methods were used in order to prevent complex formation of metals with sulfate, hydroxide and decomposed organic matter present in the environmental samples. On the basis of the CE studies dilution was needed for those samples having more than 100 mg/l of sulfate, chloride, calcium and sodium. On average, the natural waters in the study contained ammonium, magnesium, sodium, potassium and calcium below 0.3, 20, 200, 20, and 200 mg/l, respectively. The concentrations of chloride, sulfate, nitrite and nitrate were below 20, 100, 10, and 10 mg/l, respectively. Correlation of the CE results with those acquired by titration, atomic absorption spectrometry, ion chromatography and flow injection analysis were obtained; R2 values for the comparison tests varied from 0.8816 to 0.9994 depending on the ion. The repeatabilities of the anion and cation CE methods were tested using laboratory-made reference sample mixtures with high and low salt concentration. PMID:12102308

  5. Water chemistry in 179 randomly selected Swedish headwater streams related to forest production, clear-felling and climate.

    Science.gov (United States)

    Löfgren, Stefan; Fröberg, Mats; Yu, Jun; Nisell, Jakob; Ranneby, Bo

    2014-12-01

    From a policy perspective, it is important to understand forestry effects on surface waters from a landscape perspective. The EU Water Framework Directive demands remedial actions if not achieving good ecological status. In Sweden, 44 % of the surface water bodies have moderate ecological status or worse. Many of these drain catchments with a mosaic of managed forests. It is important for the forestry sector and water authorities to be able to identify where, in the forested landscape, special precautions are necessary. The aim of this study was to quantify the relations between forestry parameters and headwater stream concentrations of nutrients, organic matter and acid-base chemistry. The results are put into the context of regional climate, sulphur and nitrogen deposition, as well as marine influences. Water chemistry was measured in 179 randomly selected headwater streams from two regions in southwest and central Sweden, corresponding to 10 % of the Swedish land area. Forest status was determined from satellite images and Swedish National Forest Inventory data using the probabilistic classifier method, which was used to model stream water chemistry with Bayesian model averaging. The results indicate that concentrations of e.g. nitrogen, phosphorus and organic matter are related to factors associated with forest production but that it is not forestry per se that causes the excess losses. Instead, factors simultaneously affecting forest production and stream water chemistry, such as climate, extensive soil pools and nitrogen deposition, are the most likely candidates The relationships with clear-felled and wetland areas are likely to be direct effects. PMID:25260924

  6. Water-stable fac-{TcO(3)}(+) Complexes - A new field of technetium chemistry

    OpenAIRE

    Braband, H.

    2011-01-01

    The development of technetium chemistry has been lagging behind that of its heavier congener rhenium, primarily because the inherent radioactivity of all Tc isotopes has limited the number of laboratories that can study the chemistry of this fascinating element. Although technetium is an artificial element, it is not rare. Significant amounts of the isotope (99)Tc are produced every day as a fission byproduct in nuclear power plants. Therefore, a fundamental understanding of the chemistry of ...

  7. Haloalkanes at air-water and air-ice interfaces: A computational study with implications in atmospheric chemistry and water treatment

    Czech Academy of Sciences Publication Activity Database

    Roeselová, Martina; Habartová, Alena; Minofar, Babak; Toubin, C.

    Dallas: American Chemical Society, 2014. 214PHYS. ISSN 0065-7727. [National Spring Meeting of the American Chemical Society (ACS) /247./. 16.03.2014-20.03.2014, Dallas] Institutional support: RVO:61388963 Keywords : haloalkanes * air-water interfaces * air-ice interfaces Subject RIV: CF - Physical ; Theoretical Chemistry

  8. Investigating water purification system of primary coolant circuits of Russian WWER reactor using ion exchange resins

    International Nuclear Information System (INIS)

    The protection of environment from contamination, especially radioactive material is an important task. The operation of nuclear power plants is usually with production of radioactive elements in the first element cycle, Combined using Ion Exchange Resins, The Radioactive d elements will be Separated from coolant cycle. In this project, the decontamination system of first coolant cycle in WWER power plant is considered for the determination of decontamination factor of several ion exchange resins. Amberlite and Dowex were used and after the Passing of Atomic Energy Organization of Iran-Reactor coolant water, the capability of re mines were determined. The Results indicates that Amberlite Resin has better efficiency for absorption of radioactive elements. and can be used in the first coolant cycle of WWER nuclear power plants

  9. Plasma Discharges in Gas Bubbles in Liquid Water: Breakdown Mechanisms and Resultant Chemistry

    Science.gov (United States)

    Gucker, Sarah M. N.

    The use of atmospheric pressure plasmas in gases and liquids for purification of liquids has been investigated by numerous researchers, and is highly attractive due to their strong potential as a disinfectant and sterilizer. However, the fundamental understanding of plasma production in liquid water is still limited. Despite the decades of study dedicated to electrical discharges in liquids, many physical aspects of liquids, such as the high inhomogeneity of liquids, complicate analyses. For example, the complex nonlinearities of the fluid have intricate effects on the electric field of the propagating streamer. Additionally, the liquid material itself can vaporize, leading to discontinuous liquid-vapor boundaries. Both can and do often lead to notable hydrodynamic effects. The chemistry of these high voltage discharges on liquid media can have circular effects, with the produced species having influence on future discharges. Two notable examples include an increase in liquid conductivity via charged species production, which affects the discharge. A second, more complicated scenario seen in some liquids (such as water) is the doubling or tripling of molecular density for a few molecule layers around a high voltage electrode. These complexities require technological advancements in optical diagnostics that have only recently come into being. This dissertation investigates several aspects of electrical discharges in gas bubbles in liquids. Two primary experimental configurations are investigated: the first allows for single bubble analysis through the use of an acoustic trap. Electrodes may be brought in around the bubble to allow for plasma formation without physically touching the bubble. The second experiment investigates the resulting liquid phase chemistry that is driven by the discharge. This is done through a dielectric barrier discharge with a central high voltage surrounded by a quartz discharge tube with a coil ground electrode on the outside. The plasma

  10. The ARCHIMEDE-ARGILE project: acquisition and regulation of the water chemistry in a clay formation

    International Nuclear Information System (INIS)

    The first aim of the CEC/ANDRA project known as ARCHIMEDE-ARGILE is to gain an understanding on the mechanisms of acquisition and regulation of the water chemistry in a clay environment. This step is essential for predicting both the behaviour and the migration in solution of artificial elements which are initially absent in clay formation. The second aim is to assess sampling methodology and data collection techniques for key physico-chemical parameters (pH, Eh, pCO2, CEC, alkalinity...) which are the basis of the geochemical modelling of the behaviour of natural and artificial radioelements. Six drill holes have been performed in 1992 in the sliding ribs gallery in the Underground Research Facility (URF) at Mol. The study has demonstrated the importance of in situ measurements for key parameters that cannot be rigorously evaluated otherwise: redox, pH, pCO2. Fluid geochemistry can realistically be modelled using equilibrium models, in which cation exchange must be taken into account. Bacterial studies have revealed the importance of human activity on the microbial equilibrium of the formation. This paper presents the main results obtained during the first two years of the project with emphasis on determination of the hydrochemical characteristics of the Boom clay. (author). 12 refs., 4 figs., 1 tab

  11. Mineralogy and pore water chemistry of a boiler ash from a MSW fluidized-bed incinerator.

    Science.gov (United States)

    Bodénan, F; Guyonnet, D; Piantone, P; Blanc, P

    2010-07-01

    This paper presents an investigation of the mineralogy and pore water chemistry of a boiler ash sampled from a municipal solid waste fluidized-bed incinerator, subject to 18 months of dynamic leaching in a large percolation column experiment. A particular focus is on the redox behaviour of Cr(VI) in relation to metal aluminium Al(0), as chromium may represent an environmental or health hazard. The leaching behaviour and interaction between Cr(VI) and Al(0) are interpreted on the basis of mineralogical evolutions observed over the 18-month period and of saturation indices calculated with the geochemical code PhreeqC and reviewed thermodynamic data. Results of mineralogical analyses show in particular the alteration of mineral phases during leaching (e.g. quartz and metal aluminium grains), while geochemical calculations suggest equilibria of percolating fluids with respect to specific mineral phases (e.g. monohydrocalcite and aluminium hydroxide). The combination of leaching data on a large scale and mineralogical analyses document the coupled leaching behaviour of aluminium and chromium, with chromium appearing in the pore fluids in its hexavalent and mobile state once metal aluminium is no longer available for chromium reduction. PMID:20153161

  12. Advancing the Chemistry of CuWO4 for Photoelectrochemical Water Oxidation.

    Science.gov (United States)

    Lhermitte, Charles R; Bartlett, Bart M

    2016-06-21

    Photoelectrochemical (PEC) cells are an ongoing area of exploration that provide a means of converting solar energy into a storable chemical form (molecular bonds). In particular, using PEC cells to drive the water splitting reaction to obtain H2 could provide a clean and sustainable route to convert solar energy into chemical fuels. Since the discovery of catalytic water splitting on TiO2 photoelectrodes by Fujishima and Honda, significant efforts have been directed toward developing high efficiency metal oxides to use as photocatalysts for this reaction. Improving the efficiency of PEC cells requires developing chemically stable, and highly catalytic anodes for the oxygen-evolution reaction (OER). This water oxidation half reaction requires four protons and four electrons coupling in two bond making steps to form O2, which limits the rate. Our group has accelerated efforts in CuWO4 as a candidate for PEC OER chemistry. Its small band gap of 2.3 eV allows for using visible light to drive OER, and the reaction proceeds with a high degree of chemoselectivity, even in the presence of more kinetically accessible anions such as chloride, which is common to seawater. Furthermore, CuWO4 is a chemically robust material when subjected to the highly oxidizing conditions of PEC OER. The next steps for accelerating research using this (and other), ternary phase oxides, is to move beyond reporting the basic PEC measurements to understanding fundamental chemical reaction mechanisms operative during OER on semiconductor surfaces. In this Account, we outline the process for PEC OER on CuWO4 thin films with emphasis on the chemistry of this reaction, the reaction rate and selectivity (determined by controlled-potential coulometry and oxygen-detection experiments). We discuss key challenges with CuWO4 such as slow kinetics and the presence of an OER-mediating mid-gap state, probed by electrochemical impedance spectroscopy. We propose that this mid-gap state imparts the observed

  13. Airborne Observations of Urban-Derived Water Vapor and Potential Impacts on Chemistry and Clouds

    Science.gov (United States)

    Salmon, O. E.; Shepson, P. B.; Grundman, R. M., II; Stirm, B. H.; Ren, X.; Dickerson, R. R.; Fuentes, J. D.

    2015-12-01

    Atmospheric conditions typical of wintertime, such as lower boundary layer heights and reduced turbulent mixing, provide a unique environment for anthropogenic pollutants to accumulate and react. Wintertime enhancements in water vapor (H2O) have been observed in urban areas, and are thought to result from fossil fuel combustion and urban heat island-induced evaporation. The contribution of urban-derived water vapor to the atmosphere has the potential to locally influence atmospheric chemistry and weather for the urban area and surrounding region due to interactions between H2O and other chemical species, aerosols, and clouds. Airborne observations of urban-derived H2O, carbon dioxide (CO2), methane, nitrogen dioxide (NO2), ozone, and aerosols were conducted from Purdue University's Airborne Laboratory for Atmospheric Research (ALAR) and the University of Maryland's (UMD) Twin Cessna research aircraft during the winter of 2015. Measurements were conducted as part of the collaborative airborne campaign, Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER), which investigated seasonal trends in anthropogenic emissions and reactivity in the Northeastern United States. ALAR and the UMD aircraft participated in mass balance experiments around Washington D.C.-Baltimore to determine total city emission rates of H2O and other greenhouse gases. Average enhancements in H2O mixing ratio of 0.048%, and up to 0.13%, were observed downwind of the urban centers on ten research flights. In some cases, downwind H2O concentrations clearly track CO2 and NO2 enhancements, suggesting a strong combustion signal. Analysis of Purdue and UMD data collected during the WINTER campaign shows an average urban-derived H2O contribution of 5.3%, and as much as 13%, to the local boundary layer from ten research flights flown in February and March of 2015. In this paper, we discuss the potential chemical and physical implications of these results.

  14. Chesapeake Bay earth science study: interstitial water chemistry-chemical zonation, tributaries study, and trace metals. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hill, J.M.; Blakeslee, P.J.; Conkwright, R.D.; McKeon, G.

    1982-11-01

    The sediments of the Chesapeake Bay constitute a large reservoir of chemical species derived from natural and anthropogenic sources. The behavior of these materials in the estuary is determined by the physiochemical sedimentary environments in which they are found. Three major environments are identified, from the interstitial water chemistry as Northern Bay, Middle Bay, and Southern Bay. The chemical sedimentary environments of five tributaries to the main Bay were sampled for interstitial water. The data indicate the concentration of the metals are greater than coastal seawater and river water, and comparable to concentrations found in municipal waste.

  15. Study of streamflow processes within a mediterranean catchment. An approach by stable environmental isotopes and water chemistry

    International Nuclear Information System (INIS)

    Streamflow mechanisms using stable environmental isotopes and water chemistry have been studied in the Maurets catchment (Real Collobrier, massif des Maures) over 2 years. In mediterranean climate and metamorphic context, we identify, during flood events, an important contribution of shallow pre-event water. Hydrographic separations using the natural water borne tracers reveal the evolution with time of the different flow component proportions, in relation with saturation progression. A dynamic model of flow processes is proposed where the moisture conditions before the flood play a key role. (authors). 12 refs., 5 figs

  16. Degradation of Environmental Contaminants with Water-Soluble Cobalt Catalysts: An Integrative Inorganic Chemistry Investigation

    Science.gov (United States)

    Evans, Alexandra L.; Messersmith, Reid E.; Green, David B.; Fritsch, Joseph M.

    2011-01-01

    We present an integrative laboratory investigation incorporating skills from inorganic chemistry, analytical instrumentation, and physical chemistry applied to a laboratory-scale model of the environmental problem of chlorinated ethylenes in groundwater. Perchloroethylene (C[subscript 2]Cl[subscript 4], PCE) a common dry cleaning solvent,…

  17. Does water chemistry affect the dietary uptake and toxicity of silver nanoparticles by the freshwater snail Lymnaea stagnalis?

    International Nuclear Information System (INIS)

    Silver nanoparticles (AgNPs) are widely used in many applications and likely released into the aquatic environment. There is increasing evidence that Ag is efficiently delivered to aquatic organisms from AgNPs after aqueous and dietary exposures. Accumulation of AgNPs through the diet can damage digestion and adversely affect growth. It is well recognized that aspects of water quality, such as hardness, affect the bioavailability and toxicity of waterborne Ag. However, the influence of water chemistry on the bioavailability and toxicity of dietborne AgNPs to aquatic invertebrates is largely unknown. Here we characterize for the first time the effects of water hardness and humic acids on the bioaccumulation and toxicity of AgNPs coated with polyvinyl pyrrolidone (PVP) to the freshwater snail Lymnaea stagnalis after dietary exposures. Our results indicate that bioaccumulation and toxicity of Ag from PVP-AgNPs ingested with food are not affected by water hardness and by humic acids, although both could affect interactions with the biological membrane and trigger nanoparticle transformations. Snails efficiently assimilated Ag from the PVP-AgNPs mixed with diatoms (Ag assimilation efficiencies ranged from 82 to 93%). Rate constants of Ag uptake from food were similar across the entire range of water hardness and humic acid concentrations. These results suggest that correcting regulations for water quality could be irrelevant and ineffective where dietary exposure is important. - Highlights: • AgNP coated with polyvinyl pyrrolidone (PVP), PVP-AgNP were efficiently assimilated by Lymnaea stagnalis. • Water chemistry has no influence on the dietary uptake of PVP-AgNP by snails. - L. Stagnalis assimilated PVP-AgNPs efficiently from food and water chemistry had no influence on their uptake and toxicity

  18. A teacher as researcher study of high school chemistry student ideas about the particulate nature of water

    Science.gov (United States)

    Kruckeberg, Robert Fredrick

    The objective of this study was to advance the pedagogical content knowledge base for teaching high school chemistry by conducting qualitative research on students' scientific understanding of water prior to, during, and after formal instruction on the particulate nature of matter. The study was conducted within a constructivist theoretical framework, with an emphasis on John Dewey's pragmatic social constructivism. The teacher-as-researcher conducted three sets of clinical interviews based on three related contexts: representation of water in the liquid state, interaction of water with a solute, and water vaporizing and condensing. Interviews and class work were analyzed to determine the extent to which students used the particulate nature of matter to reorganize their understanding of water. Findings present student responses in terms of four different aspects of the particulate model, where students frequently emphasized certain aspects of the model to the exclusion of others. These aspects were identified as "Simple Particles," "Mechanical Kinetic," "Differential Chemical", and "Electrostatic Interactive." Students exhibited significant difficulty in extending micro-mechanical aspects of the model into an electrostatic-interactive understanding of water. Applications of the particulate model were often highly context dependent. Students showed a variety of unique, alternative interpretations of the particulate nature of water that were supported by rich qualitative interview responses. Student difficulties understanding the particulate nature of water were attributed to alternative conceptions prior to instruction as well as the content and sequencing of the traditional biology-chemistry-physics science curriculum. The study recommends changes in curriculum sequencing, improved instruction in the nature of science and scientific models, and the need for introducing students to ideas in physics, especially electrostatics, prior to the study of introductory

  19. Development status of nuclear power in China and fundamental research progress on PWR primary water chemistry in China

    International Nuclear Information System (INIS)

    China's non-fossil fuels are expected to reach 20% in primary energy ratio by 2030. It is urgent for China to speed up the development of nuclear power to increase energy supply, reduce gas emissions and optimize resource allocation. Chinese government slowed down the approval of new nuclear power plant (NPP) projects after Fukushima accident in 2011. At the end of 2012, the State Council approved the nuclear safety program and adjusted long-term nuclear power development plan (2011-2020), the new NPP's projects have been restarted. In June 2015, there are 23 operating units in mainland in China with total installed capacity of about 21.386 GWe; another 26 units are under construction with total installed capacity of 28.5 GWe. The main type of reactors in operation and under construction in China is pressurized water reactor (PWR), including the first AP1000 NPPs in the world (units 1 in Sanmen) and China self-developed Hualong one NPPs (units 5 and 6 in Fuqing). Currently, China's nuclear power development is facing historic opportunities and also a series of challenges. One of the most important is the safety and economy of nuclear power. The optimization of primary water chemistry is one of the most effective ways to minimize radiation field, mitigate material degradation and maintain fuel performance in PWR NPPs, which is also a preferred path to achieve both safety and economy for operating NPPs. In recent years, an increased attention has been paid to fundamental research and engineering application of PWR primary water chemistry in China. The present talk mainly consists of four parts: (1) development status of China's nuclear power industry; (2) safety of nuclear power and operating water chemistry; (3) fundamental research progress on Zn-injected water chemistry in China; (4) summary and future. (author)

  20. Solubility of the constituents of sea water under the conditions of the PWR secondary circuit

    International Nuclear Information System (INIS)

    In the case of a PWR reactor sited on the coast, a condensor leak can give rise to an influx of sea water and, as a result of the increase in temperature, to the precipitation of salts or their hydrolysis products. While the solubility of calcium compounds is known, little research has been done on that of magnesium compounds at high temperatures. The solubility of the following compounds has been measured at between 20 and 300 deg. C: Ca(OH)2 (subject to confirmation), Mg(OH)2, MgSO4 and MgCO3. For M(OH)2 hydroxides, the solubility product alone has been properly defined. This constant was calculated, for Mg(OH)2 from solubility and pH measurements. In areas where the present measurements overlap with data published earlier, the results are in good agreement. In the case of Mg(OH)2, a considerable difference between the solubility of freshly precipitated hydroxide and that of aged hydroxide was revealed. To determine the possible effect of a local concentration of NaCl, the soluble products of Ca(OH)2 and Mg(OH)2 were also measured in an environment of NaCl 0.5M. In the case of magnesium only, the formation of an MgCl+ complex was discovered, which significantly increases solubility at high temperatures. Measurements of the solubility of MgSO4 in which the magnesium and sulphate were analysed separately show that hydrolysis occurs at temperatures above 150 deg. C. From the measurements performed on MgCO3 solutions at different CO2 pressures, it can be concluded that the solid in equilibrium with the solution is either MgCO3 or Mg(OH)2, depending on the CO2 pressure. (author)

  1. Proceedings of the 13. International Conference on the Properties of Water and Steam : steam, water and hydrothermal systems : physics and chemistry meeting the needs of the industry

    Energy Technology Data Exchange (ETDEWEB)

    Tremaine, P.R. [ed.] [Memorial Univ. of Newfoundland, St. John' s, NF (Canada); Hill, P.G. [ed.] [British Columbia Univ., Vancouver, BC (Canada); Irish, D.E. [ed.] [Waterloo Univ., ON (Canada); Balakrishnan, P.V. [eds.] [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    2000-07-01

    This international conference focused on the physical and chemical properties of water, steam and aqueous systems. More than 140 presentations from nearly 200 scientists presented work in applied research in physics and chemistry of hydrothermal systems which are of particular importance to the thermal power industry. This year the conference expanded into new areas of pure and applied research related to water and aqueous solutions at temperature and pressure extremes. This application is useful to electric power cycle chemistry and other industrial technologies that involve the use of high-temperature and supercritical steam. The areas of basic science that were included were: spectroscopy, calorimetry, potentiometry, PVT measurements, molecular simulation studies of water, and solvated species in high-temperature or supercooled water. The areas of application were: power cycle chemistry, high-temperature aqueous technologies that apply to new steam cycles, use of high-temperature water and supercritical steam in chemical and metallurgical processes, supercritical destruction of toxic wastes, and hydrothermal geochemistry and hydrometallurgy. refs., tabs., figs.

  2. Adventures in STEM: Lessons in Water Chemistry From Elementary School to Graduate School

    Science.gov (United States)

    Dittrich, T. M.

    2014-12-01

    I will present the accumulation of over 10 years of experience teaching STEM subjects to students ranging from 1st grade to graduate school. I was fortunate to gain a lot of valuable teaching experience while in graduate school in Boulder, CO and so many of my experiences center on opportunities for connecting with students in the field in CO. 3rd-5th grade field hikes - While helping at Jamestown Elementary School, I led hikes with a 3-5th grade class to an abandoned flourospar mine where the students were able to pick up beautiful purple fluorite crystals from the ground while discussing how mining works. During the hike back, we used field meters to measure the pH and conductivity of the stream and discussed the need to balance society's need for metals with the harmful effects of acid mine drainage. 9th, 10th grade STEM Academy at Skyline High School - During an NSF-sponsored fellowship, I had the opportunity to teach a STEM class to 9th and 10th graders where we used the engineering design process to a) design a tool to help a handicapped 3rd grader use the drinking fountain by herself and b) design a treatment system for cleaning up acid mine drainage. Undergraduate and Graduate Environmental Water Chemistry Field Trip - Students had the opportunity to tour two local mine sites to collect contaminated water that would be used in class for alkalinity titrations and pH, sulfate, and hardness measurements. They also collected water samples upstream and at multiple points downstream of a wastewater treatment plan and measured and graphed the dissolved oxygen "sag" in the river. My main teaching philosophy has two parts: 1) assume the students know nothing and 2) assume the students are even smarter than you think you are. This informs my approach to field trips by always starting from the beginning, but also not oversimplifying the topic. 1st graders on their best day can be very similar to graduate students on their worst.

  3. Experimental indications of effects of surface deprotonation on Na-bentonite pore water chemistry in a geological repository

    International Nuclear Information System (INIS)

    Bentonite-water interaction was studied using a simple equilibrium model based on experimental measurements in order to describe bentonite porewater chemistry. Direct pH measurements for highly compacted bentonite and batch-type bentonite-water interaction experiments were performed under anaerobic conditions. In the direct pH measurements, resin particles doped with a pH indicator were sandwiched between a pair of bentonite columns immersed in a test solution. The experimental results showed that the solution compositions in equilibrium with bentonite depended on the bentonite to liquid ratio (B/L) and the initial solution composition. An equilibrium model assuming only fast equilibration processes between the bentonite minerals and the solution could be used to calculate the trends of pH and other ion concentrations with B/L. This study indicates that the surface deprotonation of smectite is a very important factor influencing the porewater chemistry in highly compacted bentonite. Copyright (2001) Material Research Society

  4. The use of chromatogenic chemistry for the conception and realization of cellulosic materials, barrier to water, greases and gas.

    OpenAIRE

    Stinga, Nicoleta Camelia

    2008-01-01

    Chromatogenic chemistry is a new chemical process which allows the molecular grafting of cellulosic materials with long chain fatty acids. In this study, it was applied to design and realize cellulosic materials with barrier properties required for food packaging (barrier to water, greases, gas ...). In a first step, to deepen our understanding of the mechanism of the grafting reaction of cellulosic materials, a simple test, the “Droplet Surface Migrating Test” was developed for viewing the p...

  5. Water physics and chemistry data from moored current meter and bottle casts in the Coastal Waters of New Jersey as part of the Mesa New York Bight (MESA - NYB) project, 28 April 1977 - 19 October 1977 (NODC Accession 7800053)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected using moored current meter and bottle casts in the Coastal Waters of New Jersey from April 28, 1977 to October 19,...

  6. The possible influences of fuel crud build-up and water chemistry on waterside corrosion of zirconium alloys

    International Nuclear Information System (INIS)

    The possible effects of fuel crud build-up and water chemistry on waterside corrosion of zirconium alloys have drawn a certain attention in fuel integrity evaluation programs. This article is an attempt to explore the possible causes for such effects, based on the presumption that diffusion of oxygen vacancies in the oxide barrier layer is the rate limiting process for corrosion in reactor water environments. It is shown that fuel crud build-up and water chemistry may influence corrosion through changing the chemical reactivity at the metal/oxide and oxide/water interfaces, the oxygen vacancy concentration and the diffusivity through the oxide layer. In particular, crud build-up may increase corrosion by enhancing, for example, the oxygen content of reactor water by radiolysis at the crud/water interface and the cladding surface temperature. The presence of fuel crud may also affect ZrO2 grain growth and its phase transformation, which are also closely related to the corrosion kinetics. (author)

  7. Primary processes in radiation chemistry. LET (Linear Energy Transfer) effect in water radiolysis

    International Nuclear Information System (INIS)

    The effect of ionizing radiations on aqueous solutions leads to water ionization and then to the formation of radical species and molecular products (e-aq, H., OH., H2O2, H2). It has been shown that the stopping power, characterized by the LET value (Linear Energy Transfer) becomes different when the nature of the ionizing radiations is different. Few data are nowadays available for high LET radiations such as protons and high energy heavy ions. These particles have been used to better understand the primary processes in radiation chemistry. The yield of a chemical dosimeter (the Fricke dosimeter) and those of the hydrogen peroxide have been determined for different LET. The effect of the dose rate on the Fricke dosimeter yield and on the H2O2 yield has been studied too. When the dose rate increases, an increase of the molecular products yield is observed. At very high dose rate, this yield decreases on account of the attack of the molecular products by radicals. The H2O2 yield in alkaline medium decreases when the pH reaches 12. This decrease can be explained by a slowing down of the H2O2 formation velocity in alkaline medium. Superoxide radical has also been studied in this work. A new detection method: the time-resolved chemiluminescence has been perfected for this radical. This technique is more sensitive than the absorption spectroscopy. Experiments with heavy ions have allowed to determine the O2.- yield directly in the irradiation cell. The experimental results have been compared with those obtained with a Monte Carlo simulation code. (O.M.)

  8. Trait modality distribution of aquatic macrofauna communities as explained by pesticides and water chemistry.

    Science.gov (United States)

    Ieromina, O; Musters, C J M; Bodegom, P M; Peijnenburg, W J G M; Vijver, M G

    2016-08-01

    Analyzing functional species' characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2-4 % to pesticides, and for 3-11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches. PMID:27209569

  9. The Irminger Sea and the Iceland Sea time series measurements of sea water carbon and nutrient chemistry 1983–2008

    Directory of Open Access Journals (Sweden)

    J. Olafsson

    2010-03-01

    Full Text Available This paper describes the ways and means of assembling and quality controling the Irminger Sea and Iceland Sea time-series biogeochemical data which are included in the CARINA data set. The Irminger Sea and the Iceland Sea are hydrographically different regions where measurements of sea water carbon and nutrient chemistry were started in 1983. The sampling is seasonal, four times a year. The carbon chemistry is studied with measurements of the partial pressure of carbon dioxide in seawater, pCO2, and total dissolved inorganic carbon, TCO2. The carbon chemistry data are for surface waters only until 1991 when water column sampling was initiated. Other measured parameters are salinity, dissolved oxygen and the inorganic nutrients nitrate, phosphate and silicate. Because of the CARINA criteria for secondary quality control, depth >1500 m, the IRM-TS could not be included in the routine QC and the IS-TS only in a limited way. However, with the information provided here, the quality of the data can be assessed, e.g. on the basis of the results obtained with the use of reference materials.

  10. The Irminger Sea and the Iceland Sea time series measurements of sea water carbon and nutrient chemistry 1983–2006

    Directory of Open Access Journals (Sweden)

    J. Olafsson

    2009-10-01

    Full Text Available This paper describes the ways and means of assembling and quality controling the Irminger Sea and Iceland Sea time-series biogeochemical data which are included in the CARINA data set. The Irminger Sea and the Iceland Sea are hydrographically different regions where measurements of sea water carbon and nutrient chemistry were started in 1983. The sampling is seasonal, four times a year. The carbon chemistry is studied with measurements of the partial pressure of carbon dioxide in seawater, pCO2, and total dissolved inorganic carbon, TCO2. The carbon chemistry data are for surface waters only until 1994 when water column sampling was initiated. Other measured parameters are salinity, dissolved oxygen and the inorganic nutrients nitrate, phosphate and silicate. Because of the CARINA criteria for secondary quality control, depth >1500 m, the IRM-TS could not be included in the routine QC and the IS-TS only in a limited way. However, with the information provided here, the quality of the data can be assessed e.g. on the basis of the results obtained with the use of reference materials.

  11. Measurement of in-core and recirculation system response to hydrogen water chemistry at Nine Mile Point 1

    International Nuclear Information System (INIS)

    The value of hydrogen water chemistry (HWC) as a mitigation technique for out-of-core piping systems susceptible to intergranular stress corrosion cracking (IGSCC) is well established. However, certain reactor internal components exposed to high levels of radiation are susceptible to a cracking mechanism referred to as irradiation assisted stress corrosion cracking (IASCC). Some of the components potentially affected by IASCC include the top guide, SRM/IRM housings, the core shroud, and control blades. Fortunately, laboratory data indicate that IASCC can be controlled by altering the coolant environment. Hot cell tests performed at GE's Vallecitos Nuclear Center (VNC) on highly irradiated material produced a fracture surface with 99% IGSCC under normal BWR water chemistry. However, under HWC conditions, only ductile failure occurred. With this background, a program was established to determine the chemistry and oxidizing potential of the core bypass coolant at Nine Mile Point-1 (NMP-1) under normal and HWC conditions. The objective of the program was to assess whether HWC could sufficiently modify the core bypass environment to mitigate IASCC. Results showed that with the addition of hydrogen to the feedwater, core bypass dissolved oxygen decreased very rapidly, compared to the recirculation water, indicating very efficient recombination of hydrogen and oxygen in the non-boiling core bypass region. Since low concentrations of dissolved oxygen have been shown to eliminate IASCC, these results are encouraging. 8 figs., 1 tab

  12. Experience with chemistry control of primary circuit and operation of high temperature and high pressure mechanical filtration at Temelin VVER-1000/320 NPP

    International Nuclear Information System (INIS)

    The primary circuit with the VVER1000-320V reactor installed in the nuclear power plant Temelin represents a world-unique technology in terms of reduction of concentration of corrosion products and activated corrosion products by means of mechanical, high-temperature and high-pressure filters. The technology uses continual filtration and its main advantage is cleaning of the primary coolant at operating parameters, i.e. without any adjustments of pressure and temperature of the filtered coolant. The filter is made of especially treated titanium, whose spongy form improves the required interception of undissolved corrosion products and activated corrosion products on its surface. It contributes to limitation of formation of radiation fields and it favorably affects reduction of the effective dose received by the plant's operating personnel. (author)

  13. NWFSC OA facility water chemistry - Ocean acidification species exposure experimental facility

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We have developed a unique facility for conducting high-quality experiments on marine organisms in seawater with controlled carbon chemistry conditions. The...

  14. Role and chemistry of catalyst in hydrogen based heavy water plants (Paper No. 6.2)

    International Nuclear Information System (INIS)

    The chemistry of homogeneous catalyst particularly of KNH2 in ammonia, based on which a number of plants are operating, is discussed. considering its importance and complexity. (author). 10 refs., 5 figs

  15. Impacts of the North Atlantic Oscillation on stream water chemistry in mid-Wales

    OpenAIRE

    L. Ness; Neal, C.; Davies, T.D.; Reynolds, B.

    2002-01-01

    Analysis of winter stream chemistry data from the Afon Hafren in mid-Wales reveals links between stream chemistry and the North Atlantic Oscillation (NAO). K, Y, Al and dissolved organic carbon (DOC) concentrations increase during high NAO index months (relatively warm and wet weather), while Ca, Mg and NO3 concentrations increase during low NAO months (relatively cold and dry conditions) with the increased concentrations lasting int...

  16. Impacts of the North Atlantic Oscillation on stream water chemistry in mid-Wales

    OpenAIRE

    L. Ness; Neal, C.; Davies, T.D.; Reynolds, B.

    2004-01-01

    Analysis of winter stream chemistry data from the Afon Hafren in mid-Wales reveals links between stream chemistry and the North Atlantic Oscillation (NAO). K, Y, Al and dissolved organic carbon (DOC) concentrations increase during high NAO index months (relatively warm and wet weather), while Ca, Mg and NO3 concentrations increase during low NAO months (relatively cold and dry conditions) with the increased concentrations lasting into the next month. The cause of the concentration c...

  17. High temporal resolution water chemistry information for catchment understanding and management

    Science.gov (United States)

    Reaney, S. M.; Deasy, C.; Ockenden, M.; Perks, M.; Quinton, J.

    2013-12-01

    Many rivers and lakes are currently not meeting their full ecological potential due to environmental pressures including non-point source pollution from the catchment. These pressures include sediment, nitrogen and phosphorus from agriculture and other sources. Each of these pollutants is transferred through the landscape with different hydrological processes and along different pathways. Therefore, to effectively select and spatially target mitigation actions in the landscape, an understanding of the dominant hydrological processes and dynamics which are causing the transfer of material is required. Recent advances in environmental monitoring have enabled the collection of new rich datasets with a high temporal sampling frequency. In the UK, these techniques have been implemented in the Defra Demonstration Test Catchments project and with Natural England for targeted site investigations. Measurements include weather, hydrological flows, sediment, oxygen isotopes, nitrogen and phosphorus from a combination of in-field labs, water chemistry sondes and storm samplers. The detailed time series data can then be analysed to give insights into catchment processes through the analysis of the measured process dynamics. For example, evidence of the transfer of material along surface (or pipe) flow paths can be found from the co-incident timing of the sediment and flow record, or the timing of temperature variations after a storm event can give insight into the contribution of shallow groundwater. Given this evidence of catchment hydrological dynamics it is possible to determine the probable pathways which are transferring pollutants and hence it is possible to select suitable mitigation options in the landscape to improve the river or lake. For example, evidence of a pollutant transfer occurring as shallow soil flows suggests that buffer strips would not be an effective solution since these measures intercept surface pathways. Information on catchment residence time not

  18. Approaches to enhancing early hydrogen water chemistry for IGSCC mitigation during BWR startups

    International Nuclear Information System (INIS)

    Boiling Water Reactors (BWRs) have been injecting hydrogen into the reactor coolant via the feedwater system for the purpose of controlling primary system intergranular stress corrosion cracking (IGSCC) for over 30 years. However, plant design limitations prevent hydrogen injection until there is sufficient steam flow to support operation of the Steam Jet Air Ejector (SJAE) system, which typically occurs at greater than 5% power. The time from when the reactor coolant temperature is heated up to 200°F (93.3°C) until hydrogen injection starts is counted as time when IGSCC is not mitigated. Laboratory data show that crack growth rates peak at intermediate temperatures. To address this gap, Early Hydrogen Water Chemistry (EHWC) was developed by EPRI/BWRVIP for plants that use GE Hitachi NobleChem™ to lower the electrochemical corrosion potential (ECP) during early startup. A demonstration of EHWC performed at Peach Bottom 3 in October 2011 showed that sufficient hydrogen could be injected, while condenser vacuum was being maintained using the Mechanical Vacuum Pump (MVP), before steam flow was sufficient to place the SJAE system in service, to lower the ECP to a level indicative of IGSCC mitigation. While this demonstration successfully showed that sufficient hydrogen can be injected safely to mitigate IGSCC during early startup when temperature was between 360°F and 460°F (182 – 238°C), a reactor coolant hydrogen:oxidants molar ratio >2 was not achieved during the initial heatup when the temperature reached 200°F (93.3°C). This paper provides the results of a BWRVIP investigation of options to mitigate IGSCC at all temperatures above 200°F (93.3°C) for BWRs that apply noble metals. Options investigated for plants that have applied noble metal include 1) plant capabilities to achieve conditions at which IGSCC can be mitigated from 200°F (93.3°C) and above through the use of hydrogen alone and 2) the use of other agents, including hydrazine or methanol

  19. Approach to mitigate intergranular stress corrosion cracking and dose rate reduction rate by water chemistry control in Tokai-2

    International Nuclear Information System (INIS)

    The Japan Atomic Power Company (JAPC) had been working on material replacement and measures to mitigate stress in order to maintain the integrity of the structural material of Tokai-Daini nuclear power plant (Tokai-2, BWR, 1,100 MWe; commercial operation started on November 28, 1978). In addition, as Stress Corrosion Cracking (SCC) environmental mitigation measures, we have been reducing the sulfate ion concentration in the reactor water by improving the regeneration method of the ion exchange resin at condensate purification system. Furthermore, in conducting the SCC environmental mitigation measures by applying hydrogen water chemistry (HWC) and HWC during start-up (HDS), we have been reducing the oxidizing agent concentration in the reactor water. On the other hand, as a plant that has not installed condensate filters, we have been working on feed water iron concentration reduction measures in Tokai-2 as part of the dose reduction measures. Therefore, we have improved condensate demineralizer's ion exchange resin and the ion exchange resin cleaning method using the ARCS (Advanced Resin Cleaning System) in order to improve the iron removal performance of condensate demineralizer. This document reports the improvement effect of the SCC environmental mitigation measures and the dose reduction measures by water chemistry management at Tokai-2. In addition, the dose reduction effect of the recently applied zinc injection, and the Electrochemical Corrosion Potential (ECP) monitoring plan under the On-Line Noble Chemical Addition (OLNC™) to be implemented later shall be introduced. (author)

  20. Dangerous Pressurization and Inappropriate Alarms during Water Occlusion of the Expiratory Circuit of Commonly Used Infant Ventilators

    Science.gov (United States)

    Perdomo, Aldo

    2016-01-01

    Background Non-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or ‘rainout’ from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected and excessive repetitive airway pressurisation in a Draeger VN500 prompted a systematic bench test examination of currently available ventilators. Objective To assess neonatal ventilator response to partial or complete expiratory limb occlusion when set to non-invasive continuous positive airway pressure mode. Design Seven commercially available neonatal ventilators connected to a test lung using a standard infant humidifier circuit with partial and/or complete expiratory limb occlusion were examined in a bench test study. Each ventilator was set to deliver 6 cmH2O in non-invasive mode and respiratory mechanics data for 75%, 80% and 100% occlusion were collected. Results Several ventilators responded inappropriately with complete occlusion by cyclical pressurisation/depressurisation to peak pressures of between 19·4 and 64·6 cm H2O at rates varying between 2 to 77 inflations per minute. Tidal volumes varied between 10·1 and 24·3mL. Alarm responses varied from ‘specific’ (tube occluded) to ‘ambiguous’ (Safety valve open). Carefusion Avea responded by continuing to provide the set distending pressure and displaying an appropriate alarm message. Draeger Babylog 8000 did not alarm with partial occlusions and incorrectly displayed airways pressure at 6·1cmH2O compared to the measured values of 13cmH2O. Conclusions This study found a potential for significant adverse ventilator response due to complete or near complete expiratory limb occlusion in CPAP mode. PMID:27116224

  1. Disentangling the effects of water chemistry and substratum structure on moss-dwelling unicellular and multicellular micro-organisms in spring-fens

    Directory of Open Access Journals (Sweden)

    Michal HORSÁK

    2011-09-01

    Full Text Available Water chemistry is known to be one of the most important factors controlling species composition of many macro-organisms in wetlands. It is unclear to what extent micro-organisms respond to water chemistry as compared to chemistry-mediated substratum structure. We explored how the assemblages of different groups of micro-organisms in bryophyte tufts of spring-fens were determined by water chemistry and substratum structure. The aim was to compare unicellular autotrophic diatoms, unicellular heterotrophic testate amoebae and multicellular heterotrophic monogonont rotifers. Assemblages of all three groups showed a strong compositional gradient correlated with water pH and conductivity, calcium concentration and dominance of Sphagnum. While a second strong gradient in species composition of diatoms and testate amoebae was explained by factors such as substratum structure and water content, that of rotifers remained unexplained. Unlike the other two groups, testate amoeba assemblages were significantly determined by phosphates. Nitrates and iron were important species composition determinants for diatoms. Rotifers differed from the other groups in that they did not respond significantly to silica, iron or nutrients. When variation caused by substratum characteristics and water chemistry were partitioned out, testate amoebae were controlled more by substratum, while rotifers and diatoms were controlled more by water chemistry. Variation explained by individual effects of substratum or water chemistry, as compared to shared effects, was much lower for rotifers than for testate amoebae and diatoms. Our results show that, in semi-terrestrial ecosystems, pH and calcium concentrations are generally the main drivers of variation in species composition of unicellular and multicellular microorganisms, mirroring well described patterns for macro-organisms, providing support for general ecological hypotheses. Other water chemistry variables differed between

  2. Effects of loading mode and water chemistry on stress corrosion crack growth behavior of 316L HAZ and weld metal materials in high temperature pure water

    International Nuclear Information System (INIS)

    The stress corrosion cracking (SCC) growth rates of 316L weld heat-affected zone (HAZ) and weld metal materials in high temperature pure water at 288deg. C were measured using contoured double cantilever beam (CDCB) specimens and an alternating current potential drop (ACPD) in situ crack-length monitoring system. The effects of loading mode and dissolved oxygen and hydrogen on crack growth rate (CGR) were experimentally quantified. Typical intergranular SCC was found in the HAZ specimen and interdendritic SCC was identified in the weld metal specimen. The HAZ specimen and the weld metal specimen showed quite a similar response to the applied loading modes and the water chemistry, even though their absolute CGR values were different. The crack growth rates under trapezoidal loading were moderately higher than those under constant loading by several tenths percent. Switching the water chemistry from the oxygen-bearing water to the hydrogen-bearing water drastically decreased the electrochemical potential and the crack growth rate, and vice versa. A time-lag period for crack growth was observed after switching the water chemistry back to the oxygen-bearing water, where the crack growth rate was low even the dissolved oxygen concentration and the electrochemical potential had become high. Strain hardening and the resultant uneven distribution of deformation contribute to the enhanced intergranular SCC growth behavior in the HAZ area. The crack growth kinetics is analyzed based on the deformation/oxidation interaction at the crack tip, considering the importance of the electric-charge transfer, mass transport kinetics and the crack tip strain rate

  3. Effects of runoff from agricultural catchments on fishpond water chemistry: A long-term study from Třeboň fishponds

    Czech Academy of Sciences Publication Activity Database

    Pechar, Libor; Bastl, J.; Hais, M.; Kröpfelová, L.; Pokorný, Jan; Štíchová, J.; Šulcová, J.

    Wageningen : Wageningen Academic Publishing, 2005 - (Dunne, E.; Reddy, K.; Carton, O.), s. 28-33 ISBN 90-76998612 Institutional research plan: CEZ:AV0Z60870520 Keywords : water chemistry * fishponds * Agricultural catchment Subject RIV: DA - Hydrology ; Limnology

  4. Investigation of primary cooling water chemistry following the partial meltdown of Pu-Be neutron source in Tehran Research Reactor Core (TRR)

    International Nuclear Information System (INIS)

    Research highlights: → Effect of Pu-Be neutron source meltdown in core on reactor water chemistry. → Water chemistry of primary cooling before, during and after of above incident was compared. → Training importance. → Management of nuclear incident and accident. - Abstract: Effect of Pu-Be neutron source meltdown in core on reactor water chemistry was main aim of this study. Leaving the neutron source in the core after reactor power exceeds a few hundred Watts was the main reason for its partial meltdown. Water chemistry of primary cooling before, during and after of above incident was compared. Activity of some radio-nuclides such as Ba-140, La-140, I-131, I-132, Te-132 and Xe-135 increased. Other radio-nuclides such as Nd-147, Xe-133, Sr-91, I-133 and I-135 are also detected which were not existed before this incident.

  5. Water physics and chemistry data from bottle casts from the AQUALAB from 14 October 1968 to 11 December 1968 (NODC Accession 7100270)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the AQUALAB from 14 October 1968 to 11 December 1968. Data were submitted by the Southern...

  6. Water physics and chemistry data from bottle casts from the DELAWARE from 10 May 1967 to 01 June 1967 (NODC Accession 7000769)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the DELAWARE from 10 May 1967 to 01 June 1967. Data were submitted by the National Marine...

  7. Water physics and chemistry data from bottle casts from the LITTLEHALES from 05 August 1959 to 10 August 1959 (NODC Accession 7000734)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the LITTLEHALES from 05 August 1959 to 10 August 1959. Data were submitted by the US Navy;...

  8. Water physics and chemistry data from bottle casts from the BLUE FIN from 26 February 1976 to 26 May 1976 (NODC Accession 7800050)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the BLUE FIN from 26 February 1976 to 26 May 1976. Data were submitted by the Skidaway...

  9. Water physics and chemistry data from bottle casts from the LANGLEY and other platforms from 27 November 1961 to 18 July 1963 (NODC Accession 7300511)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the LANGLEY and other platforms from 27 November 1961 to 18 July 1963. Data were submitted by...

  10. The corrosion behavior of Alloy 52 weld metal in cyclic hydrogenated and oxygenated water chemistry in high temperature aqueous environment

    International Nuclear Information System (INIS)

    Highlights: • Ecorr and film resistance in DO and DH periods differ largely. • Oxide film shows two types of semi conductivity in different potential ranges. • Electric and electrochemical properties are changeable during chemical fatigue. • The morphology and composition of the oxide film are unchangeable. - Abstract: The corrosion behavior of Alloy 52 weld metal in cyclic hydrogenated and oxygenated water chemistry in high temperature water is studied by in situ monitoring corrosion potential (Ecorr), contact electric resistance (CER) and electrochemical impedance measurements (EIS), and ex situ scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The Ecorr and film resistance show large change when the environment is changed from hydrogenated water to oxygenated water and changeable with changing environment while the morphology and composition only show obvious distinction in the first cycle. The main factor controlling the electric/electrochemical properties of the oxide film is Ecorr

  11. Calculation for the water chemistry condition in the spent fuel pool in Fukushima-Daiichi Nuclear Power Station

    International Nuclear Information System (INIS)

    The evaluation for the possibility of the occurrence of the leakage of cooling water and fuel by the localized corrosion of the structural materials of the spent fuel pool (SFP) and the cladding tube of the fuel assembly in the SFP is important. To evaluate the localized corrosion of these materials experimentally, the water chemistry condition in the SFP is needed. In this study, the water radiolysis calculation was performed for the water chemistry condition in SFP. The oxygen (O2) and nitrogen (N2) gas are dissolved in the cooling water in SFP due to the exposure to the air. And the hydrazine (N2H4) injection is carried out to mitigate the O2 concentration in SFP and suppress the microbiological corrosion. So, the secondary reactions for the dissolved N2 and the N2H4 were installed into the water radiolysis calculation in this study. In order to confirm the suitability of the calculation, the comparisons of calculated results with experimentally measured results were performed for the species with long life time. Major results are as follows; 1) The set of the secondary reactions containing dissolved N2 and N2H4 were prepared. The calculated results using the set relatively agreed with the measured results for the species with long life time. 2) The mitigation of dissolved O2 by the injection of N2H4 under gamma-ray irradiation was successfully reproduced. 3) The calculated change in pH by the generation of NO3- by the water radiolysis for the water containing dissolved N2 relatively agreed with measured results. 4) The dissolved O2 concentration was calculated for the N2H4 injection condition in SFP. It was confirmed that the dissolved O2 was enough mitigated near the fuel assemblies by the reaction of dissolved O2 with the injected N2H4 enhanced by the irradiation form the fuel assemblies. (author)

  12. THE EFFECT OF SEVERAL NON-OXIDIZING BIOCIDES ON FINE PAPER WET-END CHEMISTRY

    OpenAIRE

    Patrick Huber; Bruno Carré; Elisa Zeno

    2010-01-01

    Biocide programs have become necessary in most fine paper manufacturing circuits, as drastic reduction of fresh water consumption in the industry enhances microbial development. Depending on their chemical nature, biocides may interfere with typical wet-end chemistry additives and furnish. A reference wet-end chemistry was set (including fixing aid, dry strength aid, sizing agent, and retention system), then biocides were added to the furnish (bleached virgin fibres + mineral filler) prior to...

  13. Seasonal and spatial variabilities in the water chemistry of prairie pothole wetlands influence the photoproduction of reactive intermediates.

    Science.gov (United States)

    McCabe, Andrew J; Arnold, William A

    2016-07-01

    The hydrology and water chemistry of prairie pothole wetlands vary spatially and temporally, on annual and decadal timescales. Pesticide contamination of wetlands arising from agricultural activities is a foremost concern. Photochemical reactions are important in the natural attenuation of pesticides and may be important in limiting ecological and human exposure. Little is known, however, about the variable influence of wetland water chemistry on indirect photochemistry. In this study, seasonal water samples were collected from seven sites throughout the prairie pothole region over three years to understand the spatiotemporal dynamics of reactive intermediate photoproduction. Samples were classified by the season in which they were collected (spring, summer, or fall) and the typical hydroperiod of the wetland surface water (temporary or semi-permanent). Under photostable conditions, steady-state concentrations and apparent quantum yields or quantum yield coefficients were measured for triplet excited states of dissolved organic matter, singlet oxygen, hydroxyl radical, and carbonate radical under simulated sunlight. Steady-state concentrations and quantum yields increased on average by 15% and 40% from spring to fall, respectively. Temporary wetlands had 40% higher steady-state concentrations of reactive intermediates than semi-permanent wetlands, but 50% lower quantum yields. Computed quantum yields for reactive intermediate formation were used to predict the indirect photochemical half-lives of seven pesticides in average temporary and semi-permanent prairie pothole wetlands. As a first approximation, the predictions agree to within two orders of magnitude of previously reported half-lives. PMID:27174849

  14. SCC crack growth of cold-worked type 316 SS in simulated BWR oxidizing and hydrogen water chemistry conditions

    International Nuclear Information System (INIS)

    There is considerable interest in the stress corrosion cracking (SCC) susceptibility of austenitic stainless steels in low electrochemical potential (ECP), light water reactor (LWR) environments. Crack growth measurements are presented for ∼20% cold-worked, 316 and 316L stainless steels tested in 288oC high-purity water under oxidizing (2000 ppb O2) and hydrogen water chemistry (74-1560 ppb H2) conditions. High SCC crack-growth rates of ∼1x10-7 mm/s at constant K were observed in one heat at low ECP, hydrogen water chemistry conditions. Crack morphologies for this heat were mixed intergranular (IG) and transgranular (TG) for all environments but with less TG cracking at the lowest K level tested. Comparisons made to a larger set of data on cold-worked stainless steels indicate that the SCC crack-growth rates from PNNL on this heat are at the high end of test data under low ECP, LWR conditions. Possible reasons for the higher observed SCC propagation rates in the cold-worked 316LSS heat are discussed. (author)

  15. The ion chemistry of surface and ground waters in the Taklimakan Desert of Tarim Basin, western China

    Institute of Scientific and Technical Information of China (English)

    ZHU BingQi; YANG XiaoPing

    2007-01-01

    The physio-chemical and chemical features of water in natural conditions are controlled by the weathering of bedrocks, local climate, landforms and other geo-environmental parameters. In order to understand the characteristics of water and the origins of the dissolved loads in the rivers and in the ground waters of the Taklimakan Desert, western China, we studied the ions in the water samples collected from rivers and wells. We collected water samples from four rivers (Keriya River, Cele River, Tumiya River and Yulongkashi River) in the southern desert and ground water samples from many parts of the desert. Major cations and anions were measured using ion-chromatograph and titration with HCl. The total dissolved solids (TDS), pH and conductivity were examined on site by a portable multi-parameter analyzer. The data show that the water in the rivers of southern Taklimakan is still of fresh water quality and slight alkalinity, although the TDS is comparatively higher than that of many other rivers of the world. The ground water is fresh to slightly saline, with TDS a little higher than that of river water in the study area. The concentration of ions is slightly different between the four rivers in the southern Taklimakan. However, the chemistries of ground water in all samples are to a large degree controlled by sodium and chloride. The ions in the ground water are concluded to be mainly from dissolving of evaporites, consistent with the dry climate in the region, whereas the ions in the rivers are mainly from rock weathering. Low-level human imprints are recognized in the ground water samples also.

  16. Aespoe Hard Rock Laboratory. Prototype Repository. Analyses of microorganisms, gases and water chemistry in buffer and backfill, 2009

    International Nuclear Information System (INIS)

    The Prototype repository is an international project to build and study a full-scale model of the planned Swedish final repository for spent nuclear fuel. The Prototype repository differs from a real storage in that it is drained. For example, this makes the swelling pressure lower in the Prototype repository compared with a real storage. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and one of the specific aims is to monitor the microbial consumption of oxygen in situ in the Prototype repository. This document describes the results of the analyses of microbes, gases, and chemistry inside and outside the Prototype in 2009. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed in the following sampling points in the Prototype repository: KBU10001, KBU10002, KBU10004, KBU10006, KBU10008, KFA01 and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e., the biovolume), cultivable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), autotrophic acetogens (AA) and in some cases iron-reducing bacteria (IRB). Cultivation methods were also compared with qPCR molecular techniques to evaluate these before next year's decommission of the Prototype repository. The collected pore water from the Prototype repository was subject to chemistry analysis (as many analyses were conducted as the amount of water allowed). In addition, groundwater from two borehole sections in the rock surrounding the Prototype was analysed regarding its gas composition, microbiology and redox. Chemistry data from a previous investigation of the groundwater outside the Prototype repository were compared with the pore water chemistry

  17. Aespoe Hard Rock Laboratory. Prototype Repository. Analyses of microorganisms, gases and water chemistry in buffer and backfill, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Lydmark, Sara (Microbial Analytics Sweden AB (Sweden))

    2010-09-15

    The Prototype repository is an international project to build and study a full-scale model of the planned Swedish final repository for spent nuclear fuel. The Prototype repository differs from a real storage in that it is drained. For example, this makes the swelling pressure lower in the Prototype repository compared with a real storage. The project is being conducted at the Aespoe Hard Rock Laboratory (HRL) in crystalline rock at a depth of approximately 450 m. A monitoring programme is investigating the evolution of the water chemistry, gas, and microbial activity at the site, and one of the specific aims is to monitor the microbial consumption of oxygen in situ in the Prototype repository. This document describes the results of the analyses of microbes, gases, and chemistry inside and outside the Prototype in 2009. Hydrogen, helium, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, and ethene were analysed in the following sampling points in the Prototype repository: KBU10001, KBU10002, KBU10004, KBU10006, KBU10008, KFA01 and KFA04. Where the sampling points in the Prototype delivered pore water, the water was analysed for amount of ATP (i.e., the biovolume), cultivable heterotrophic aerobic bacteria (CHAB), sulphate-reducing bacteria (SRB), methane-oxidizing bacteria (MOB), autotrophic acetogens (AA) and in some cases iron-reducing bacteria (IRB). Cultivation methods were also compared with qPCR molecular techniques to evaluate these before next year's decommission of the Prototype repository. The collected pore water from the Prototype repository was subject to chemistry analysis (as many analyses were conducted as the amount of water allowed). In addition, groundwater from two borehole sections in the rock surrounding the Prototype was analysed regarding its gas composition, microbiology and redox. Chemistry data from a previous investigation of the groundwater outside the Prototype repository were compared with the pore water

  18. Molecular dynamics simulations of small halogenated organics at the air-water interface: implications in water treatment and atmospheric chemistry

    Czech Academy of Sciences Publication Activity Database

    Habartová, Alena; Valsaraj, K. T.; Roeselová, Martina

    2013-01-01

    Roč. 117, č. 38 (2013), s. 9205-9215. ISSN 1089-5639 R&D Projects: GA ČR GA13-06181S Institutional support: RVO:61388963 Keywords : aerosol * air bubbles * interfacial concentration Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.775, year: 2013

  19. Identification of key factors governing chemistry in groundwater near the water course recharged by reclaimed water at Miyun County, Northern China

    Institute of Scientific and Technical Information of China (English)

    Yilei Yu; Xianfang Song; Yinghua Zhang; Fandong Zheng; Ji Liang; Dongmei Han; Ying Ma

    2013-01-01

    Reclaimed water was successfully used to recover the dry Chaobai River in Northern China,but groundwater may be polluted.To ensure groundwater protection,it is therefore critical to identify the governing factors of groundwater chemistry.Samples of reclaimed water,river and groundwater were collected monthly at Chaobai River from January to September in 2010.Fifteen water parameters were analyzed.Two kinds of reclaimed water were different in type (Na-Ca-Mg-C1-HCO3 or Na-Ca-Cl-HCO3) and concentration of nitrogen.The ionic concentration and type in river were similar to reclaimed water.Some shallow wells near the river bed had the same type (Na-Ca-Mg-Cl-HCO3) and high concentration as reclaimed water,but others were consistent with the deep wells (Ca-Mg-HCO3).Using cluster analysis,the 9 months were divided into two periods (dry and wet seasons),and all samples were grouped into several spatial clusters,indicating different controlling mechanisms.Principal component analysis and conventional ionic plots showed that calcium,magnesium and bicarbonate were controlled by water-rock interaction in all deep and some shallow wells.This included the dissolution of calcite and carbonate weathering.Sodium,potassium,chloride and sulfate in river and some shallow wells recharged by river were governed by evaporation crystallization and mixing of reclaimed water.But groundwater chemistry was not controlled by precipitation.During the infiltration of reclaimed water,cation exchange took place between (sodium,potassium) and (calcium,magnesium).Nitrification and denitrification both happened in most shallow groundwater,but only denitrification in deep groundwater.

  20. Water-Chemistry Evolution and Modeling of Radionuclide Sorption and Cation Exchange during Inundation of Frenchman Flat Playa

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald; Cablk, Mary; LeFebre, Karen; Fenstermaker, Lynn; Decker, David

    2013-08-01

    valuable information about chemical processes occurring during inundation as the water disappeared. Important observations from water-chemistry analyses included: 1) total dissolved solids (TDS) and chloride ion (Cl-) concentrations were very low (TDS: < 200 mg/L and Cl-: < 3.0 mg/L, respectively) for all water samples regardless of time or areal extent; 2) all dissolved constituents were at concentrations well below what might be expected for evaporating shallow surface waters on a playa, even when 98 to 99 percent of the water had disappeared; 3) the amount of evaporation for the last water samples collected at the end of inundation, estimated with the stable isotopic ratios δ2H or δ18O, was approximately 60 percent; and 4) water samples analyzed by gamma spectroscopy did not show any man-made radioactivity; however, the short scanning time (24 hours) and relative chemical diluteness of the water samples (TDS ranged between 39 and 190 mg/L) may have contributed to none being detected. Additionally, any low-energy beta emitting radionuclides would not have been detected by gamma spectroscopy. From these observations, it was apparent that a significant portion of water on the playa did not evaporate, but rather infiltrated into the subsurface (approximately 40 percent). Consistent with this water chemistry-based conclusion is particle-size analysis of two archived Frenchman Flat playa soils samples, which showed low clay content in the near surface soil that also suggested infiltration. Infiltration of water from the playa during inundation into the subsurface does not necessarily imply that groundwater recharge is occurring, but it does provide a mechanism for moving residual radionuclides downward into the subsurface of Frenchman Flat playa. Water-mineral geochemical reactions were modeled so that changes in the water chemistry could be identified and the extent of reactions quantified. Geochemical modeling showed that evaporation; equilibrium with atmospheric carbon