Production of heavy water in India

International Nuclear Information System (INIS)

Deshpande, P.G.; Bimbhat, K.S.; Bhargava, R.K.

India's first heavy water plant, using electrolysis of water followed by liquid hydrogen distillation, has been operating in association with a fertilizer plant at Nangal since 1962. A dual-temperature process plant at Kota uses heat from the Rajasthan Atomic Power Station. The heavy water plants at Baroda and Tuticorin use ammonia-hydrogen exchange and are integrated with fertilizer ammonia plants. Choice of a particular process for heavy water production depends upon local conditions as well as the extent of the heavy water requirement

Canadian heavy water production

International Nuclear Information System (INIS)

Dahlinger, A.; Lockerby, W.E.; Rae, H.K.

1977-05-01

The paper reviews Canadian experience in the production of heavy water, presents a long-term supply projection, relates this projection to the anticipated long-term electrical energy demand, and highlights principal areas for further improvement that form the bulk of our research and development program on heavy water processes

Power control device for heavy water moderated reactor

International Nuclear Information System (INIS)

Matsushima, Hidesuke; Masuda, Hiroyuki.

1978-01-01

Purpose: To improve self controllability of a nuclear power plant, as well as enable continuous power level control by a controlled flow of moderators in void pipes provided in a reactor core. Constitution: Hollow void pipes are provided in a reactor core to which a heavy water recycle loop for power control, a heavy water recycle pump for power control, a heavy water temperature regulator and a heavy water flow rate control valve for power control are connected in series to constitute a heavy water recycle loop for flowing heavy water moderators. The void ratio in each of the void pipes are calculated by a process computer to determine the flow rate and the temperature for the recycled heavy water. Based on the above calculation result, the heavy water temperature regulator is actuated by way of a temperature setter at the heavy water inlet and the heavy water flow rate is controlled by the actuation of the heavy water flow rate control valve. (Kawakami, Y.)

Numerical analysis and optimisation of heavy water upgrading column

International Nuclear Information System (INIS)

Sankar, Rama; Ghosh, Brindaban; Bhanja, K.

2013-01-01

In the 'Pressurised Heavy Water' type of reactors, heavy water is used both as moderator and coolant. During operation of reactor downgraded heavy water is generated that needs to be upgraded for reuse in the reactor. When the isotopic purity of heavy water becomes less than 99.75%, it is termed as downgraded heavy water. Downgraded heavy water also contains impurity such as corrosion products, dirt, oil etc. Upgradation of downgraded heavy water is normally done in two steps: (i) Purification: In this step downgraded heavy water is first purified to remove corrosion products, dirt, oil, etc. and (ii) Upgradation of heavy water to increase its isotopic purity, this step is carried out by vacuum distillation of downgraded heavy water after purification. This project is aimed at mathematical modelling and numerical simulation of heavy water upgrading column. Modelling and simulation studies of the upgradation column are based on equilibrium stage model to evaluate the effect of feed location, pressure, feed composition, reflux ratio in the packed column for given reboiler and condenser duty of distillation column. State to stage modelling of two-phase two-component flow has constitutes the overall modelling of the column. The governing equations consist of stage-wise species and overall mass continuity and stage-wise energy balance. This results in tridigonal matrix equation for stage liquid fractions for heavy and light water. The stage-wise liquid flow rates and temperatures are governed by stage-wise mass and energy balance. The combined form of the corresponding governing equations, with the incorporation of thermodynamic equation of states, form a system of nonlinear equations. This system have been resolved numerically using modified Newton-Raphson method. A code in the MATLAB platform has been developed by on above numerical procedure. The optimisation of the column operating conditions is to be carried out based on parametric studies and analysis of different

Assessment of irradiation effects on beryllium reflector and heavy water tank of JRR-3M

Energy Technology Data Exchange (ETDEWEB)

Murayama, Yoji; Kakehuda, Kazuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-10-01

The JRR-3M, a swimming pool type research reactor with beryllium and heavy water reflectors, has been operated since 1990. Since the beryllium reflectors are close to fuel and receive high fast neutron fluence in a relatively short time, they may be subject to change their dimensions by swelling due mostly to entrapped helium gaseous. This may bend the reflectors to the outside and narrow gaps between the reflectors and the fuel elements. The gaps have been measured with an ultrasonic thickness gage in an annual inspection. The results in 1996 show that the maximum of expansion in the diametral directions was 0.6 mm against 1.6 mm of a managed value for replacement of the reflector. A heavy water tank of the JRR-3M is made of aluminum alloy A5052. Surveillance tests of the alloy have been conducted to evaluate irradiation effects of the heavy water tank. Five sets of specimens of the alloy have been irradiated in the beryllium reflectors where fast neutron flux is higher than that in the heavy water tank. In 1994, one set of specimens had been unloaded and carried out the post-irradiation tests. The results show that the heavy water tank preserved satisfactory mechanical properties. (author)

Survival of tumor-bearing mice exposed to heavy water or heavy water plus methotrexate

International Nuclear Information System (INIS)

Laissue, J.A.; Buerki, H.; Berchtold, W.

1982-01-01

Moderate body deuteration combined with a cytostatic drug [methotrexate (MTX)] significantly increases the survival time of young adult DBA/2 mice bearing transplantable P815. L5178Y, or L1210 tumors. Neoplastic cells were grown in vitro from tumor stock and injected i.p. into mice from two groups, one drinking tap water, and other drinking 30% heavy water in tap water. One-half of the animals in each of these two groups was given a single injection of MTX (4 mg/kg body weight) on 3 consecutive days per week. At death, extension of primary and metastatic tumors was examined and was found to be macro- and microscopically comparable in the corresponding groups. The mean survival time of untreated mice drinking tap water was about 2 weeks following injection of the fast-growing P815, L5178Y, or L1210 (V) tumors and approximately 5 weeks after injection of cells from a slower-growing L1210 subline. Body deuteration alone roughly doubled the survival time solely of mice bearing this L1210 subline. Treatment with MTX approximately doubled the mean survival time of hosts bearing one of the fast-growing tumors. Combined treatment with heavy water and MTX increased the mean survival time of the mice in all groups by 15 to 125% as compared to control values. The reasons for this effect are unknown. However, heavy water has been shown to exert antimitotic activity and to depress the incorporation of radioactive precursors into DNA of proliferating mammalian cells. The depression of antibody formation following antigenic stimulation and the reduction in numbers of nonneoplastic lymphoid cells of mice following moderate body deuteration may have contributed to the enhancement of MTX activity in addition to other effects of deuterium

[Effect of Recycled Water Irrieation on Heavy Metal Pollution in Irrigation Soil].

Science.gov (United States)

Zhou, Yi-qi; Liu, Yun-xia; Fu, Hui-min

2016-01-15

With acceleration of urbanization, water shortages will become a serious problem. Usage of reclaimed water for flushing and watering of the green areas will be common in the future. To study the heavy metal contamination of soils after green area irrigation using recycled wastewater from special industries, we selected sewage and laboratory wastewater as water source for integrated oxidation ditch treatment, and the effluent was used as irrigation water of the green area. The irrigation units included broad-leaved forest, bush and lawn. Six samples sites were selected, and 0-20 cm soil of them were collected. Analysis of the heavy metals including Cr, Mn, Ni, Cu, Zn, As, Cd and Pb in the soil showed no significant differences with heavy metals concentration in soil irrigated with tap water. The heavy metals in the soil irrigated with recycled water were mainly enriched in the surface layer, among which the contents of Cr, Ni, Cu, Zn and Pb were below the soil background values of Beijing. A slight pollution of As and Cd was found in the soil irrigated by recycled water, which needs to be noticed.

Alternate applications of heavy water in biological and technological fields

International Nuclear Information System (INIS)

Bhaskaran, M.; Prakash, R.

2005-01-01

Deuterium and its various compounds like heavy water exhibit distinctly different properties when compared to hydrogen and its compounds. The differences in properties are due to the primary and secondary isotopic effects. Though heavy water has been used solely for nuclear applications so far, its applications in life sciences and high technology areas are fast emerging. Heavy Water Board has taken up development of alternate applications of heavy water. The study taken up has indicated superior thermal stability for oral polio vaccine prepared in heavy water. This study has revealed various opportunities for application of heavy water or deuterium in life sciences and the paper dwells on these possibilities. The higher stability of compounds with deuterium has also brought in its applications in various high technology areas. These are mainly in micro electronics. Use of deuterium in manufacture of high quality optical fibres has already been established. These are also included in the paper. (author)

Thermal conductivity coefficients of water and heavy water in the liquid state up to 3700C

International Nuclear Information System (INIS)

Le Neindre, B.; Bury, P.; Tufeu, R.; Vodar, B.

1976-01-01

The thermal conductivity coefficients of water and heavy water of 99.75 percent isotopic purity were measured using a coaxial cylinder apparatus, covering room temperature to their critical temperatures, and pressures from 1 to 500 bar for water, and from 1 to 1000 bar for heavy water. Following the behavior of the thermal conductivity coefficient of water, which shows a maximum close to 135 0 C, the thermal conductivity coefficient of heavy water exhibits a maximum near 95 0 C and near saturation pressures. This maximum is displaced to higher temperatures when the pressure is increased. Under the same temperature and pressure conditions the thermal conductivity coefficient of heavy water was lower than for water. The pressure effect was similar for water and heavy water. In the temperature range of our experiments, isotherms of thermal conductivity coefficients were almost linear functions of density

Method of controlling power of a heavy water reactor

International Nuclear Information System (INIS)

Masuda, Hiroyuki.

1975-01-01

Object: To adjust a level of heavy water in a region of reflection body to control power in a heavy water reactor. Structure: The interior of a core tank filled with heavy water is divided by a partition into a core heavy water region and a reflection body region formed by surrounding the core heavy water region, and a level of heavy water within the reflection body region is adjusted to control power. Preferably, it is desirable to communicate the core heavy water region with the reflection body heavy water region at their lower portion, and gas pressure applied to an upper portion within at least one of said regions is adjusted to adjust the level of heavy water within the reflection body heavy water region. Thereby, the heavy water within the reflection body heavy water region may be introduced into the core region, thus requiring no tank which stores heavy water within the reflection body region. (Kamimura, M.)

Measurement of concentration of heavy water

International Nuclear Information System (INIS)

Tsukamoto, Yuichi; Kondo, Mitsuo; Sakurai, Naoyuki

1979-01-01

The concentration of heavy water is measured as one of the technical management in the Fugen plant. The heavy water is used as the moderator in the reactor. The measuring method depends on the theory of light absorption. The light absorption range of heavy water spreads from near infrared to infrared zone. The near infrared absorption was adopted for the purpose, as the absorption is much larger in infrared zone, and the measurement has to be conducted, limiting the apparent absorption. This measuring method is available to determine the concentration of heavy water in the broad range exactly. The preparation of heavy water sample and the measurement of the absorption spectra of near infrared ray are explained, as the experimental procedure. The sample cell was made of quartz, and the spectroscope was the Hitachi 323 type. The resolving power is 100 nm and 27 nm for the wave length of 1000 nm and 2500 nm, respectively. Concerning the measured results, the absorption was recorded in the wave length range from 600 nm to 2600 nm, and for the heavy water concentration range from 0 to 99.77 wt. %. The peaks of absorption were located at the wave length of 1450, 1660, 1920, 1970, 2020 and 2600 nm. The three kinds of fundamental vibration mode of the molecules of both light and heavy water are shown, and the peaks belong to H 2 O, HDO and D 2 O, respectively. The relation between the absorption and the heavy water concentration, and that between the transmissivity and the wave length are shown, when the cell thickness was varied to 5 mm and 20 mm, and the heavy water concentration to 21%, 62% and 99.85%. (Nakai, Y.)

Heavy Metals Pollution on Surface Water Sources in Kaduna ...

African Journals Online (AJOL)

This study examine the effects of heavy metal pollutants to aquatic ecosystems and the environment by considering the role of urban, municipal, agricultural, industrial and other anthropogenic processes as sources of heavy metal pollution in surface water sources of Kaduna metropolis. Samples of the polluted water were ...

Water chemistry features of advanced heavy water reactor

International Nuclear Information System (INIS)

Sriram, Jayasree; Vijayan, K.; Kain, Vivekanad; Velmurugan, S.

2015-01-01

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)

Study of the heavy water regeneration processes

International Nuclear Information System (INIS)

Cavcic, E.

1965-11-01

Experience derived from heavy water reactor operation showed degradation and dilution of heavy water to be inevitable and depends on the type of reactor. Dilution of heavy water during operation of the RA and the RB reactors is shown in this report. Principles and procedures of heavy water regeneration by electrolysis, fractional distillation, cleaning, prevention of tritium contamination are described as well as separation columns

Heavy Water - Industrial Separation Processes

International Nuclear Information System (INIS)

Peculea, M.

1984-01-01

This monograph devoted to the heavy water production mainly presents the Romanian experience in the field which started in early sixties from the laboratory scale production and reached now the level of large scale industrial production at ROMAG-Drobeta, Romania. The book is structured in eleven chapters entitled: Overview, The main physical properties, Sources, Uses, Separation factor and equilibrium constant, Mathematical modelling of the separation process, Thermodynamical considerations on the isotope separation, Selection criteria for heavy water separation processes, Industrial installations for heavy water production, Prospects, Acknowledgements. 200 Figs., 90 Tabs., 135 Refs

Detection of gaseous heavy water leakage points in CANDU 6 pressurized heavy water reactors

International Nuclear Information System (INIS)

Park, T-K.; Jung, S-H.

1996-01-01

During reactor operation, the heavy water filled primary coolant system in a CANDU 6 Pressurized Heavy Water (PHWR) may leak through routine operations of the plant via components, mechanical joints, and during inadvertent operations etc. Early detection of leak points is therefore important to maintain plant safety and economy. There are many independent systems to monitor and recover heavy water leakage in a CANDU 6 PHWR. Methodology for early detection based on operating experience from these systems, is investigated in this paper. In addition, the four symptoms of D 2 O leakage, the associated process for clarifying and verifying the leakage, and the probable points of leakage are discussed. (author)

WHO water quality standards Vs Synergic effect(s) of fluoride, heavy metals and hardness in drinking water on kidney tissues

Science.gov (United States)

Wasana, Hewa M. S.; Perera, Gamage D. R. K.; Gunawardena, Panduka De S.; Fernando, Palika S.; Bandara, Jayasundera

2017-02-01

Despite WHO standards, waterborne diseases among the human being are rising alarmingly. It is known that the prolong exposure to contaminated water has major impact on public health. The effect of chemical contaminations in drinking water on human being is found to be chronic rather than acute and hence can be defined “consumption of contaminated drinking water could be a silent killer”. As the WHO recommended water quality standards are only for individual element and synergic effects of trace metals and anions have not been considered, investigation of synergic effects of trace metals and anions and their effect on human being is of prime important research. By an animal trial, we investigated the synergic effect(s) of heavy metals, aluminium, arsenic, fluoride and hardness in drinking water on kidney tissues of mice. Our investigation strongly suggests existing of a synergic effect especially among Cd, F and hardness of water which could lead to severe kidney damage in mice, even at WHO maximum recommended levels. Hence, the synergic effect(s) of trace metals, fluoride and hardness present in drinking water should be investigated meticulously when stipulating the water quality at WHO maximum recommended levels.

Effect of operation of ammonia plants on the performance of heavy water plants (Paper No. 2.7)

International Nuclear Information System (INIS)

Anon.

1992-01-01

Heavy Water Plant, Hazira has two streams and each stream is designed to process 48 MT/hr of synthesis gas to produce the rated quantity of heavy water. However in actual practice, it is observed that actual gas composition is different from the above due to various reasons. This article describes effects of various parameters of ammonia plant on the functioning of heavy water plants, such as concentration of D/D+H in synthesis gas, concentration of hydrogen in synthesis gas, concentration of inerts in synthesis gas, pressure of synthesis gas, on stream days of ammonia plant, and concentration of impurities like CO/CO 2 in synthesis gas. (author). 2 figs

Finishing and upgrading of heavy water

International Nuclear Information System (INIS)

Butler, J.P.; Hammerli, M.

1981-01-01

This invention provides a process and apparatus for deuterium enrichment as a final stage in a heavy water plant, for continuous on-line enrichment of the heavy water in moderator and heat transfer systems in heavy water nuclear reactors, and for enrichment of hevy water that has been downgraded with natural water during the course of operating a heavy water nuclear reactor. The method comprises contacting partially-enriched heavy water feed in a catalyst column with hydrogen gas (essentially D 2 ) orginating in an electrolysis cell so as to enrich the feed water with deuterium extracted from the electrolytic hydrogen gas and passing the deuterium-enriched water to the electrolysis cell. The apparatus comprises a catalyst isotope exchange column with hydrogen gas and liquid water passing through in countercurrent isotope exchange, an electrolysis cell, a dehumidifer-scrubber; and means for passing the liquid water enriched in deuterium from the catalyst column through the dehumidifer-scrubber to the electrolysis cell, for passing the hydrogen gas evolved in the cathode side of the cell through the dehumidifier-scrubber to the catalyst column, for passing the hydrogen gas from the catalyst column to an output, for introducing an input water feed to the upper portion of the catalyst column, and for taking a product enriched in deuterium from the system. (LL)

Assessment of Loss-of-Coolant Effect on Pressurized Heavy Water Reactors

International Nuclear Information System (INIS)

Kim, Won Young; Park, Joo Hwan; Kim, Bong Ghi

2009-01-01

A CANDU reactor is a heavy-water-moderated, natural uranium fuelled reactor with a pressure tube. The reactor contains a horizontal cylindrical vessel (calandria) and each pressure tube is isolated from the heavy-water moderator in a calandria. This allows the moderator system to be operated of a high-pressure and of a high-temperature coolant in pressure tube. This causes the pressurized liquid coolant in the channel to void and therefore give rise to a reactivity transient in the event of a break or fault in the coolant circuit. In particular, all CANDU reactors are well known to have a positive void reactivity coefficient and thus this phenomenon may lead to a positive feedback, which can cause a large power pulse. We assess the loss-of-coolant effect by coolant void reactivity versus fuel burnup, four factor parameters for fresh fuel and equilibrium fuel, reactivity change due to the change of coolant density and reactivity change in the case of half- and full-core coolant

Cell growth and protein synthesis of unicellular green alga Chlamydomonas in heavy water

International Nuclear Information System (INIS)

Ishida, M.R.

1983-01-01

The effects of heavy water on the cell growth and protein synthesis of the photoautotrophically growing Chlamydomonas cells were studied. The growth rate of the cells is inversely proportional to the concentrations of heavy water. The cells can barely live in 90% heavy water, but they die in 99.85% heavy water within a few days. Incorporation of 14 Cleucine into cells is markedly stimulated by heavy water of various concentrations between 30 and 99.85% in the case of the short time incubation. Contrary to this, in the long time incubation as several days, heavy water inhibits the protein synthesis. Such two modes of the protein synthetic activities are dependent upon the incubation time of the cells grown photoautotrophically in the heavy water media. (author)

Effects of sulfate on heavy metal release from iron corrosion scales in drinking water distribution system.

Science.gov (United States)

Sun, Huifang; Shi, Baoyou; Yang, Fan; Wang, Dongsheng

2017-05-01

Trace heavy metals accumulated in iron corrosion scales within a drinking water distribution system (DWDS) could potentially be released to bulk water and consequently deteriorate the tap water quality. The objective of this study was to identify and evaluate the release of trace heavy metals in DWDS under changing source water conditions. Experimental pipe loops with different iron corrosion scales were set up to simulate the actual DWDS. The effects of sulfate levels on heavy metal release were systemically investigated. Heavy metal releases of Mn, Ni, Cu, Pb, Cr and As could be rapidly triggered by sulfate addition but the releases slowly decreased over time. Heavy metal release was more severe in pipes transporting groundwater (GW) than in pipes transporting surface water (SW). There were strong positive correlations (R 2  > 0.8) between the releases of Fe and Mn, Fe and Ni, Fe and Cu, and Fe and Pb. When switching to higher sulfate water, iron corrosion scales in all pipe loops tended to be more stable (especially in pipes transporting GW), with a larger proportion of stable constituents (mainly Fe 3 O 4 ) and fewer unstable compounds (β-FeOOH, γ-FeOOH, FeCO 3 and amorphous iron oxides). The main functional iron reducing bacteria (IRB) communities were favorable for the formation of Fe 3 O 4 . The transformation of corrosion scales and the growth of sulfate reducing bacteria (SRB) accounted for the gradually reduced heavy metal release with time. The higher metal release in pipes transporting GW could be due to increased Fe 6 (OH) 12 CO 3 content under higher sulfate concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heavy water at Aswan

International Nuclear Information System (INIS)

1959-01-01

A fertilizer factory is being built by Egyptian Chemical Industries (Kima) at Aswan on the upper Nile; it will produce a mixture of ammonium nitrate and calcium carbonate adjusted to contain 20.5% nitrogen. It is also proposed to construct a heavy water plant to be located at and integrated with the fertilizer factory. At the request of the Government of the United Arab Republic, the International Atomic Energy Agency sent an expert to carry out investigation of the technical, economic and other related aspects of the proposed production of heavy water. A report was submitted to the IAEA Director General. Its main conclusions can be summarized as follows: (1) Production of heavy water as a by-product of fertilizer manufacture at Aswan is technically feasible. Separation of deuterium from industrial hydrogen for this purpose could be done either by catalytic exchange or by liquefaction and distillation; the choice should depend on economic considerations. (2) The heavy water produced at Aswan should be competitive in cost with that produced elsewhere; this, however, would depend on whether firm contracts are obtained for the delivery of equipment at guaranteed prices and with guaranteed performance, and whether such prices are in reasonable agreement with preliminary estimates. (3) The future market for heavy water is difficult to predict. For one thing, there is a very large production capacity in the USA, most of which is idle due to lack of demand. Secondly, there is a relatively small production outside the USA that is sold at prices higher than that charged by the US Government. The future of the market is necessarily contingent upon the possibility of future free sale by the US Government. At the end of his report, the expert has also given his comments on possible further assistance to the project by IAEA

Indian heavy water programme - challenges and opportunities

International Nuclear Information System (INIS)

Aruldoss Kanthiah, W.S.

2010-01-01

Discovery of fission of uranium in 1939 opened up hitherto unknown possibilities for utilising the fission energy for use of mankind, mainly for the production of and electrical energy. It was realised that this nuclear energy could be an ideal substitute for the fast depleting fossil fuels which would one day get exhausted. Two main concepts of nuclear power reactor got evolved, one enriched uranium fuelled, ordinary water moderated reactor and another natural uranium fuelled heavy water moderated reactor. The concentration of uranium 235 U needed for ordinary water moderated reactors is 3% but the naturally occurring uranium in India contains only 0.7% of 235 U. The reactors utilising natural uranium as fuel require Heavy Water as moderator. The processing of uranium ore to achieve from 0.7% to 3% is highly complex. Recognising the fact that India has limited uranium resources but rich thorium resources, Dr. Bhabha formulated a three stage nuclear power generation programme for our country. The first generation reactors can use natural uranium as fuel with heavy water as moderator. Since the technology to generate such large scale heavy water to match the urgent need for nuclear power generation was not indigenously available, the technology available with Canada and France was utilised for installation of first generation heavy water plants in India. However, the peaceful nuclear experiment conducted by India in 1974 caused resentment among the countries that supplied Heavy Water technology to India and they stopped all technological help and assistance in nuclear field. Thereafter, it was the story of India going alone in heavy water production. That made India meets successfully all challenges on the way to installation, commissioning and sustained operation of all plants. Today we have six operating Heavy Water plants, spread all over the country. We have reached a stage, a change from a situation of crunch to a level of not only self sufficiency but to a

Technical status study of heavy water enrichment

International Nuclear Information System (INIS)

Sukarsono; Imam Dahroni; Didik Herhady

2007-01-01

Technical status study of heavy water enrichment in Indonesia and also in the world has been done. Heavy water enrichment processes have been investigated were water distillation, hydrogen distillation, laser enrichment, electrolysis and isotop exchange. For the isotop exchange, the chemical pair can be used were water-hydrogen sulphite, ammonium-hydrogen, aminomethane-hydrogen, and water-hydrogen. For the isotope exchange, there was carried out by mono thermal or bi thermal. The highest producer of heavy water is Canada, and the other producer is USA, Norwegian and India. The processes be used in the world are isotope exchange Girdler Sulphide (GS), distillation and electrolysis. Research of heavy water carried out in Batan Yogyakarta, has a purpose to know the characteristic of heavy water purification. Several apparatus which has erected were 3 distillation column: Pyrex glass of 2 m tall, stainless steel column of 3 m tall and steel of 6 m tall. Electrolysis apparatus is 50 cell electrolysis and an isotope exchange unit which has catalyst: Ni- Cr 2 O 3 and Pt-Carbon. These apparatus were not ready to operate. (author)

Canadian heavy water production

International Nuclear Information System (INIS)

Dahlinger, A.; Lockerby, W.E.; Rae, H.K.

1977-01-01

The paper reviews Canadian experience in the production of heavy water, presents a long-term supply projection, relates this projection to the anticipated long-term electrical energy demand, and highlights principal areas for further improvement that form the bulk of the Canadian R and D programme on heavy water processes. Six Canadian heavy water plants with a total design capacity of 4000Mg/a are in operation or under construction. All use the Girdler-Sulphide (GS) process, which is based on deuterium exchange between water and hydrogen sulphide. Early operating problems have been overcome and the plants have demonstrated annual capacity factors in excess of 70%, with short-term production rates equal to design rates. Areas for further improvement are: to increase production rates by optimizing the control of foaming to give both higher sieve tray efficiency and higher flow rates, to reduce the incapacity due to deposition of pyrite (FeS 2 ) and sulphur (between 5% and 10%), and to improve process control and optimization of operating conditions by the application of mathematical simulations of the detailed deuterium profile throughout each plant. Other processes being studied, which look potentially attractive are the hydrogen-water exchange and the hydrogen-amine exchange. Even if they become successful competitors to the GS process, the latter is likely to remain the dominant production method for the next 10-20 years. This programme, when related to the long-term electricity demand, indicates that heavy water supply and demand are in reasonable balance and that the Candu programme will not be inhibited because of shortages of this commodity. (author)

Topical and working papers on heavy water requirements and availability

International Nuclear Information System (INIS)

The documents included in this report are: Heavy water requirements and availability; technological infrastructure for heavy water plants; heavy water plant siting; hydrogen and methane availability; economics of heavy water production; monothermal, water fed heavy water process based on the ammonia/hydrogen isotopic exchange; production strategies to meet demand projections; hydrogen availability; deuterium sources; the independent UHDE heavy water process

The heavy water accountancy for research reactors in JAERI

International Nuclear Information System (INIS)

Yoshijima, Tetsuo; Tanaka, Sumitoshi; Nemoto, Denjirou

1998-11-01

The three research reactors have been operated by the Department of Research Reactor and used about 41 tons heavy water as coolant, moderator and reflector of research reactors. The JRR-2 is a tank type research reactor of 10MW in thermal power and its is used as moderator, coolant and reflector about 16 tons heavy water. The JRR-3M is a light water cooled and moderated pool type research reactor with a thermal power of 20MW and its is used as reflector about 7.3 tons heavy water. In the JRR-4, which is a light water cooled swimming pool type research reactor with the maximum thermal power of 3.5MW, about 1 ton heavy water is used to supply fully thermalized neutrons with a neutron beam experiment of facility. The heavy water was imported from U.S.A., CANADA and Norway. Parts of heavy water is internationally controlled materials, therefore management of heavy water is necessary for materials accountancy. This report described the change of heavy water inventories in each research reactors, law and regulations for accounting of heavy water in JAERI. (author)

Energy conservation and management strategies in Heavy Water Plants

International Nuclear Information System (INIS)

Kamath, H.S.

2002-01-01

In the competitive industrial environment it is essential that cost of the product is kept at the minimum possible. Energy conservation is an important aspect in achieving this as energy is one of the key recourses for growth and survival of industry. The process of heavy water production being very complex and energy intensive, Heavy Water board has given a focussed attention for initiating various measures for reducing the specific energy consumption in all the plants. The initiative resulted in substantial reduction in specific energy consumption and brought in savings in cost. The cumulative reduction of specific energy consumption has been over 30% over the last seven years and the total savings for the last three years on account of the same has been about Rs. 190 crore. The paper describes the strategies adopted in the heavy water plants for effecting the above achievements. The paper covers the details of some of the energy saving schemes carried out at different heavy water plants through case studies. The case studies of schemes implemented at HWPs are general in nature and is applicable for any other industry. The case studies cover the modifications with re-optimisation of the process parameters, improvements effected in utility units like refrigeration and cooling water systems, improvements in captive power plant cycle and improved recycle scheme for water leading to reduced consumptions. The paper also mentions the innovative ammonia absorption refrigeration with improved coefficient of performance and HWB's efforts in development of the system as an integrated unit of the ammonia water deuterium exchange process for heavy water production. HWB also has taken up R and D on various other schemes for improvements in energy consumption for future activities covering utilisation of low grade energy for generation of refrigeration. (author)

Chemistry in production of heavy water and industrial solvents

International Nuclear Information System (INIS)

Thomas, P.G.

2015-01-01

Industries are the temples of modern science built on the robust foundation of science and technology. The genesis of giant chemical industries is from small laboratories where the scientific thoughts are fused and transformed into innovative technologies Heavy water production is an energy intensive giant chemical industry where various hazardous and flammable chemicals are handled, extreme operating conditions are maintained and various complex chemical reactions are involved. Chemistry is the back bone to all chemical industrial activities and plays a lead role in heavy water production also. Heavy Water Board has now mastered the technology of design, construction, operation and maintenance of Heavy Water plants as well as fine tuning of the process make it more cost effective and environment friendly. Heavy Water Board has ventured into diversified activities intimately connected with our three stages of Nuclear Power Programme. Process development for the production of nuclear grade solvents for the front end and back end of our nuclear fuel cycle is one area where we have made significant contributions. Heavy Water Board has validated, modified and fine-tuned the synthesis routes for TBP, D2EHPA, TOPO, TAPO TIAP, DNPPA, D2EHPA-II, DHOA etc and these solvents were accepted by end users. Exclusive campaigns were carried out in laboratory scale, bench scale and pilot plant scale before scaling up to industrial scale. The process chemistry is understood very well and chemical parameters were monitored in every step of the synthesis. It is a continual improvement cycle where fine tuning is carried out for best quality and yield of product at lowest cost. In this presentation, an attempt is made to highlight the role of chemistry in the production of Heavy Water and industrial solvents

Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries.

Science.gov (United States)

Chowdhury, Shakhawat; Mazumder, M A Jafar; Al-Attas, Omar; Husain, Tahir

2016-11-01

Heavy metals in drinking water pose a threat to human health. Populations are exposed to heavy metals primarily through water consumption, but few heavy metals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavy metals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavy metals, mainly due to their limited economic capacities to use advanced technologies for heavy metal removal. This paper aims to review the state of research on heavy metals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavy metals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavy metals in drinking water. Copyright © 2016 Elsevier B.V. All rights reserved.

The Canadian heavy water situation

International Nuclear Information System (INIS)

Dahlinger, A.

1975-08-01

Existing heavy water plants in Canada are producing at a satisfactory rate and currently planned capacity is in balance with projected needs. By 1980, we shall have Girdler-Sulphide plants installed with a design capacity of almost 600 kg/h. Effort is required to minimize production costs for heavy water and to ensure that costs do not increase faster than the current inflationary trend. (Author)

Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries

International Nuclear Information System (INIS)

Chowdhury, Shakhawat; Mazumder, M.A. Jafar; Al-Attas, Omar; Husain, Tahir

2016-01-01

Heavy metals in drinking water pose a threat to human health. Populations are exposed to heavy metals primarily through water consumption, but few heavy metals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavy metals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavy metals, mainly due to their limited economic capacities to use advanced technologies for heavy metal removal. This paper aims to review the state of research on heavy metals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavy metals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavy metals in drinking water. - Highlights: • Co-exposure to multiple heavy metals in drinking water needs better understanding • Low-cost technologies for arsenic removal needs urgent attention • Protonated alginate needs further research for drinking water applications • Community level and PoU devices need improvement and cost reduction • Developing countries are most affected by heavy metals in drinking water

Heavy metals in drinking water: Occurrences, implications, and future needs in developing countries

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Shakhawat, E-mail: Schowdhury@kfupm.edu.sa [Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Mazumder, M.A. Jafar [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Attas, Omar [Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Husain, Tahir [Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John’s, NL (Canada)

2016-11-01

Heavy metals in drinking water pose a threat to human health. Populations are exposed to heavy metals primarily through water consumption, but few heavy metals can bioaccumulate in the human body (e.g., in lipids and the gastrointestinal system) and may induce cancer and other risks. To date, few thousand publications have reported various aspects of heavy metals in drinking water, including the types and quantities of metals in drinking water, their sources, factors affecting their concentrations at exposure points, human exposure, potential risks, and their removal from drinking water. Many developing countries are faced with the challenge of reducing human exposure to heavy metals, mainly due to their limited economic capacities to use advanced technologies for heavy metal removal. This paper aims to review the state of research on heavy metals in drinking water in developing countries; understand their types and variability, sources, exposure, possible health effects, and removal; and analyze the factors contributing to heavy metals in drinking water. This study identifies the current challenges in developing countries, and future research needs to reduce the levels of heavy metals in drinking water. - Highlights: • Co-exposure to multiple heavy metals in drinking water needs better understanding • Low-cost technologies for arsenic removal needs urgent attention • Protonated alginate needs further research for drinking water applications • Community level and PoU devices need improvement and cost reduction • Developing countries are most affected by heavy metals in drinking water.

IR analyzer spots heavy water leaks

International Nuclear Information System (INIS)

Anon.

1978-01-01

A correlation spectrometer developed by Barringer Research Ltd. (in collaboration with Atomic Energy of Canada and Ontario Hydro) is used to measure HDO concentrations in DTO in the final (distillation) stage of heavy-water production. A unit has been installed at Bruce Heavy Water Plant. Previously, such spectrometers had been installed to detect heavy-water leaks in CANDU reactors. The principle on which the instrument works is explained, with illustrations. It works by comparing the absorption at 2.9 μm, due to HDO, with that at 2.6 μm, due to both HDO and D 2 O. (N.D.H.)

Moderator clean-up system in a heavy water reactor

International Nuclear Information System (INIS)

Sasada, Yasuhiro; Hamamura, Kenji.

1983-01-01

Purpose: To decrease the fluctuation of the poison concentration in heavy water moderator due to a heavy water clean-up system. Constitution: To a calandria tank filled with heavy water as poison-containing moderators, are connected both end of a pipeway through which heavy water flows and to which a clean-up device is provided. Strongly basic resin is filled within the clean-up device and a cooler is disposed to a pipeway at the upstream of the clean-up device. In this structure, the temperature of heavy water at the inlet of the clean-up device at a constant level between the temperature at the exit of the cooler and the lowest temperature for the moderator to thereby decrease the fluctuation in the poison concentration in the heavy water moderator due to the heavy water clean-up device. (Moriyama, K.)

Future trends in heavy water production

International Nuclear Information System (INIS)

Galley, M.R.

1983-10-01

World heavy water production has spanned nearly fifty years and, for much of that period, the commodity was often in short supply, but that situation has changed, at least in Canada. There are now adequate reserves of heavy water and sufficient installed production capacity to service Canadian domestic and export demands for the next ten years or beyond. More than 90 percent of the world's inventory of heavy water has been produced by the GS process but this may not be the method that is chosen when the time comes to expand heavy water production again. Other countries, such as India and Argentina, have already chosen ammonia-hydrogen exchange as an alternative technology for part of their domestic production programs. Despite the present surplus of heavy water, research and development of new technologies is very active, particularly in Canada and Japan, because it is recognized that there are still attractive opportunities for future production by processes that are both less expensive and environmentally more acceptable, than either the demonstrated GS process or ammonia-hydrogen alternative. This paper describes the prospects for some of these new processes, contrasts them with the present established methods and assesses the probable impact on the future supply situation

Water issues associated with heavy oil production.

Energy Technology Data Exchange (ETDEWEB)

Veil, J. A.; Quinn, J. J.; Environmental Science Division

2008-11-28

Crude oil occurs in many different forms throughout the world. An important characteristic of crude oil that affects the ease with which it can be produced is its density and viscosity. Lighter crude oil typically can be produced more easily and at lower cost than heavier crude oil. Historically, much of the nation's oil supply came from domestic or international light or medium crude oil sources. California's extensive heavy oil production for more than a century is a notable exception. Oil and gas companies are actively looking toward heavier crude oil sources to help meet demands and to take advantage of large heavy oil reserves located in North and South America. Heavy oil includes very viscous oil resources like those found in some fields in California and Venezuela, oil shale, and tar sands (called oil sands in Canada). These are described in more detail in the next chapter. Water is integrally associated with conventional oil production. Produced water is the largest byproduct associated with oil production. The cost of managing large volumes of produced water is an important component of the overall cost of producing oil. Most mature oil fields rely on injected water to maintain formation pressure during production. The processes involved with heavy oil production often require external water supplies for steam generation, washing, and other steps. While some heavy oil processes generate produced water, others generate different types of industrial wastewater. Management and disposition of the wastewater presents challenges and costs for the operators. This report describes water requirements relating to heavy oil production and potential sources for that water. The report also describes how water is used and the resulting water quality impacts associated with heavy oil production.

Experimental Study on Behavior of Bow-tie Tree Generation by Using Heavy Water

Science.gov (United States)

Kumazawa, Takao; Nakagawa, Wataru; Tsurumaru, Hidekazu

Bow-tie tree (BTT) generated from contaminant, e.g., metal, carbon, amber(over cured resin) or void in insulator is a significant deterioration factor of XLPE power cable. However, essential role of water in generation and progress of BTT is not yet sufficiently cleared. In order to investigate the role of water we paid attention to difference in chemical properties of light water (H2O) and heavy water (D2O), moreover we evaluated influence of isotopic effect due to hydrogen and deuterium on behavior of BTT generation. In accelerated aging test the number of BTT in XLPE sample, in which copper powder of 500ppm was contaminated as BTT cores, dipped in heavy water (D2O:100wt%) decreased to one third compared with light water(D2O:0wt%). Furthermore, the maximum length of BTT decreased with increase in concentration of heavy water. The experimental results show that heavy water exerted a depression effect on generation and progress of BTT. We considered that the depression effect due to hydrogen isotope appeared by inhibiting ionization and elution of BTT cores, because salt-solubility and ionic mobility of heavy water are about 15 to 20% smaller than those of light water. Therefore, the essential role of water seemed to be production and transport of ions in XLPE.

Ultrasonic relaxation studies associated with n-octylamine-heavy water

International Nuclear Information System (INIS)

Kor, S.K.; Singh, R.K.

1994-01-01

Ultrasonic absorption measurements have been carried out in lyotropic liquid crystalline system n-octylamine/heavy water in the frequency range 5-65 MHz and at temperatures 30 degC and 37 degC at different concentrations of heavy water in octylamine. Velocity has been measured using interferometric technique at 2 MHz at different concentrations of heavy water. Ultrasonic absorption coefficients at different concentrations in the concentration range 0.3-0.9 m.f. heavy water have been found to show a maxima in the absorption curve at critical concentration (∼0.85 m.f. heavy water). This peak has been found to shift towards lower concentrations of heavy water at higher frequencies. Results have been analysed and it has been found that single relaxation process takes place around 30 MHz and this has been attributed to aggregation of octylamine and heavy water molecules. (author). 8 refs., 6 figs., 3 tabs

Thorium in heavy water reactors

International Nuclear Information System (INIS)

Andersson, G.

1984-12-01

Advanced heavy water reactors can provide energy on a global scale beyond the foreseeable future. Their economic and safety features are promising: 1. The theoretical feasibility of the Self Sufficient Equilibrium Thorium (SSET) concept is confirmed by new calculations. Calculations show that the adjuster rod geometry used in natural uranium CANDU reactors is adequate also for SSET if the absorption in the rods is graded. 2. New fuel bundle designs can permit substantially higher power output from a CANDU reactor. The capital cost for fuel, heavy water and mechanical equipment can thereby be greatly reduced. Progress is possible with the traditional fuel material oxide, but the use of thorium metal gives much larger effects. 3. A promising long range possibility is to use pressure tanks instead of pressure tubes. Heat removal from the core is facilitated. Negative temperature and void coefficients provide inherent safety features. Refuelling under power is no longer needed if control by moderator displacement is used. Reduced quality demand on the fuel permits lower fuel costs. The neutron economy is improved by the absence of pressure and clandria tubes and also by the use of radial and axial blankets. A modular seed blanket design can reduce the Pa losses. The experience from construction of tank designs is good e.g. AAgesta, Attucha. It is now also possible to utilize technology from LWR reactors and the implementation of advanced heavy water reactors would thus be easier than HTR or LMFBR systems. (Author)

A study of Cirus heavy water system isotopic purity

International Nuclear Information System (INIS)

Thomas, Shibu; Sahu, A.K.; Unni, V.K.P.; Pant, R.C.

2000-01-01

Cirus uses heavy water as moderator and helium as cover gas. Approximately one tonne of heavy water was added to the system every year for routine make up. Isotopic purity (IP) of this water used for addition was always higher than that of the system. Though this should increase IP of heavy water in the system, it has remained almost at the same level, over the years. A study was carried out to estimate the extent of improvement in IP of heavy water in the system that should have occurred because of this and other factors in last 30 years. Reasons for non-occurrence of such an improvement were explored. Ion exchange resins used for purification of heavy water and air ingress into helium cover gas system appear to be the principal sources of entry of light water into heavy water system. (author)

Radiation safety experience in upgrading 2-5% heavy water wastes at Heavy Water Plant, Nangal (Preprint No. SA-7)

International Nuclear Information System (INIS)

Sadhukhan, H.K.; Behl, D.; Ramraj; Iyengar, T.S.; Sadarangani, S.H.; Vaze, P.K.; Soman, S.D.

1989-04-01

This paper describes the radiological safety experience in upgrading 2-5% heavy water wastes at Heavy Water Plant at Nangal at the third stage electrolysers. The feed water concentrations at the third stage electrolyer was determined after a safety analysis study and pilot plant experiment, which gave the optimal concentrations of 1 to 1.5 mCi (3.7 to 5.5 x 10 7 Bq) per litre per minute feed from a submerged SS tank containing 2-5% heavy water wastes. This process not only yielded an efficient recovery of reactor grade heavy water but contained the tritium activity in the third stage electrolysers and in the final product viz., heavy water. The tritium concentrations were continuously monitore d by liquid scintillation counting method at all the three stages of electrolysis plant, the distillation plant, the heavy water filling rooms, the drains, the ambient air, the product fertilizer (calcium ammonia nitrate) and the Sutlej River and found to be well within the safety limits set for general public at large. The HD and D 2 process streams in the palnt were monitored using fill-in type of ionization chambers designed for the purpose, which served a D 2 inventory check as well. There was no internal exposure to any personnel during the entire period of programme. (author). 2 tabs

The effects of fire temperatures on water soluble heavy metals.

Science.gov (United States)

Pereira, P.; Ubeda, X.; Martin, D. A.

2009-04-01

the heavy metals remaining in the ash are easily transported with unknown impacts on soil and water resources. Research is needed in the study at long term of the effects of fire in metals accumulation in soil resources, and all these aspects will be discussed. Keywords: Fire ash, heavy metals, Quercus suber, Quercus robur, Pinus pinea, Pinus pinaster, prescribed fire, pH, Calcite

Heavy water leak detection using diffusion sampler

International Nuclear Information System (INIS)

Joshi, M.L.; Hussain, S.A.

1990-01-01

In the Pressurrised Heavy Water Reactors (PHWRs) detection of the sources of heavy water leaks is importent both for the purpose of radiation hazard control as well as for the reduction of escape/loss of heavy water which, is an expensive nuclear material. This paper describes an application of tritium diffusion sampler for heavy water leak detection. The diffusion sampler comprises an usual tritium counting glass vial with a special orifice. The counting vial has water vapour, deficient in HTO concentration. The HTO present outside diffuses in the vial through the orifice, gets exchanged with water of the wet filter paper kept at the bottom and the moisture in the vial atmosphere which has HTO concentration lower than that outside. This results in continuation of net movement of HTO in the vial. The exchanged tritium is counted in liquid scintillation spectrometer. The method has a sensitivity of 10000 dpm/DAC-h. (author). 2 figs., 2 ta bs

Topical and working papers on heavy water accountability and safeguards

International Nuclear Information System (INIS)

This report contains the following papers: 1) Statement of IAEA concerning safeguarding of heavy water; 2) Preliminary Canadian Comments on IAEA document on heavy water safeguards; 3) Heavy water accountability 03.10.78; 4) Heavy water accountability 05.04.79

Heavy water lattices: Second panel report

International Nuclear Information System (INIS)

1963-01-01

The panel was attended by prominent physicists from most of the laboratories engaged in the field of heavy water lattices throughout the world. The participants presented written contributions and status reports describing the past history and plans for further development of heavy-water reactors. Valuable discussions took place, during which recommendations for future work were formulated. Refs, figs, tabs

Heavy water lattices: Second panel report

Energy Technology Data Exchange (ETDEWEB)

1963-09-15

The panel was attended by prominent physicists from most of the laboratories engaged in the field of heavy water lattices throughout the world. The participants presented written contributions and status reports describing the past history and plans for further development of heavy-water reactors. Valuable discussions took place, during which recommendations for future work were formulated. Refs, figs, tabs.

The Canadian heavy water supply program

International Nuclear Information System (INIS)

Dahlinger, A.; McNally, P.J.

1976-06-01

The performance to date of individual Canadian heavy water plants is described in detail as are the current plant construction plans. These data, when related to the long-term electricity demand indicate that heavy water supply and demand are in reasonable balance and that the CANDU program will not be inhibited because of shortages of the commodity. (author)

Heavy water. A production alternative for Venezuela

International Nuclear Information System (INIS)

A survey of heavy water production methods is made. Main facts about isotopic and distillation methods, reforming and coupling to a Hydrogen distillation plant are presented. A feasibility study on heavy water production in Venezuela is suggested

Heavy water physical verification in power plants

International Nuclear Information System (INIS)

Morsy, S.; Schuricht, V.; Beetle, T.; Szabo, E.

1986-01-01

This paper is a report on the Agency experience in verifying heavy water inventories in power plants. The safeguards objectives and goals for such activities are defined in the paper. The heavy water is stratified according to the flow within the power plant, including upgraders. A safeguards scheme based on a combination of records auditing, comparing records and reports, and physical verification has been developed. This scheme has elevated the status of heavy water safeguards to a level comparable to nuclear material safeguards in bulk facilities. It leads to attribute and variable verification of the heavy water inventory in the different system components and in the store. The verification methods include volume and weight determination, sampling and analysis, non-destructive assay (NDA), and criticality check. The analysis of the different measurement methods and their limits of accuracy are discussed in the paper

Removal of gadolinium nitrate from heavy water

Energy Technology Data Exchange (ETDEWEB)

Wilde, E.W.

2000-03-22

Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

Process for the extraction of tritium from heavy water

International Nuclear Information System (INIS)

Dombra, A.H.

1984-01-01

The object of the invention is achieved by a process for the extraction of tritium from a liquid heavy water stream comprising: contacting the heavy water with a countercurrent gaseous deuterium stream in a column packed with a water-repellent catalyst such that tritium is transferred by isotopic exchange from the liquid heavy water stream to the gaseous deuterium stream

Method of operating heavy water moderated reactors

International Nuclear Information System (INIS)

Masuda, Hiroyuki.

1980-01-01

Purpose: To enable stabilized reactor control, and improve the working rate and the safety of the reactor by removing liquid poison in heavy water while maintaining the power level constant to thereby render the void coefficient of the coolants negative in the low power operation. Method: The operation device for a heavy water moderated reactor comprises a power detector for the reactor, a void coefficient calculator for coolants, control rods inserted into the reactor, a poison regulator for dissolving poisons into or removing them out of heavy water and a device for removing the poisons by the poison regulator device while maintaining the predetermined power level or inserting the control rods by the signals from the power detector and the void coefficient calculator in the high temperature stand-by conditions of the reactor. Then, the heavy water moderated reactor is operated so that liquid poisons in the heavy water are eliminated in the high temperature stand-by condition prior to the start for the power up while maintaining the power level constant and the plurality of control rods are inserted into the reactor core and the void coefficient of the coolants is rendered negative in the low power operation. (Seki, T.)

Heavy water pumps; Pumpe D{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Zecevic, V; Nikolic, M

1963-12-15

Continuous increase of radiation intensity was observed on all the elements in the heavy water system during first three years of RA reactor operation. The analysis of heavy water has shown the existence of radioactive cobalt. It was found that cobalt comes from stellite, cobalt based alloy which was used for coating of the heavy water pump discs in order to increase resistance to wearing. Cobalt was removed from the surfaces due to friction, and transferred by heavy water into the reactor where it has been irradiated for 29 876 MWh up to 8-15 Ci/g. Radioactive cobalt contaminated all the surfaces of aluminium and stainless steel parts. This report includes detailed description of heavy water pumps repair, exchange of stellite coated parts, decontamination of the heavy water system, distillation of heavy water. [Serbo-Croat] U toku prve tri godine eksploatacije reaktora RA uocen je neprekidni porast intenziteta zracenja na svim elementima u teskovodnom sistemu. Analizom teske vode utvrdjeno je postojanje radioaktivnog kobalta. Ustanovljeno je da kobalt potice od stelita, legure na bazi kobalta kojim su presvuceni rukavci vratila teskovodnih pumpi radi otpornosi na habanje. Kobalt je trenjem skidan sa povrsina, u toku rada prenosen je teskom vodom u reaktor i ozracivan u toku 29 876 MWh do specificne aktivnosti 8-15 Ci/g. Radioaktivni kobalt je kontaminirao sve povrsine od aluminijuma i nerdjajuceg celika. Ovaj izvestaj sadrzi detaljan opis remonta pumpi, zamene delova teskovodnih pumpi novim delovima bez stelitnog sloja, dekontaminacije teskovodnog sistema, destilacije teske vode.

A Drinking Water Sensor for Lead and Other Heavy Metals.

Science.gov (United States)

Lin, Wen-Chi; Li, Zhongrui; Burns, Mark A

2017-09-05

Leakage of lead and other heavy metals into drinking water is a significant health risk and one that is not easily detected. We have developed simple sensors containing only platinum electrodes for the detection of heavy metal contamination in drinking water. The two-electrode sensor can identify the existence of a variety of heavy metals in drinking water, and the four-electrode sensor can distinguish lead from other heavy metals in solution. No false-positive response is generated when the sensors are placed in simulated and actual tap water contaminated by heavy metals. Lead detection on the four-electrode sensor is not affected by the presence of common ions in tap water. Experimental results suggest the sensors can be embedded in water service lines for long-time use until lead or other heavy metals are detected. With its low cost (∼$0.10/sensor) and the possibility of long-term operation, the sensors are ideal for heavy metal detection of drinking water.

Reactivity effect of a heavy water tank as reflector in the IPEN/MB-01 reactor

International Nuclear Information System (INIS)

Santos, Adimir dos; Fuga, Rinaldo

2013-01-01

This experiment comprises a set of experiments performed in the IPEN/MB-01 reactor and described in the International Handbook of Evaluated Reactor Physics Benchmark Experiments, specifically the experiment aim to evaluate the reactivity due to the heavy water tank placed at reflector region of the IPEN/MB-01 reactor. An aluminum tank was designed to be filled with heavy water and positioned at the west face of the IPEN/MB-01, additionally the experiment was also designed to allow variable heavy water height inside of this tank providing different neutron leakage rate in the west face of the IPEN/MB-01, consequently providing a series of interesting combinations. The measured quantities in the experiment are reactivities and critical control bank positions for several combinations of the control banks and an excess of reactivity of the heavy water tank. The experiment will be simulated using a Monte Carlo code MCNP in order to compare the different critical control bank position. (author)

Alkali metal and ammonium chlorides in water and heavy water (binary systems)

CERN Document Server

Cohen-Adad, R

1991-01-01

This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

Procedure for operating a heavy water cooled power reactor

International Nuclear Information System (INIS)

Rau, P.; Kumpf, H.

1981-01-01

Nuclear reactors cooled by heavy water usually have equipment for fuel element exchange during operation, with the primary circuit remaining contained. This fuel element exchange equipment is expensive and complicated in many respects. According to the invention, the heavy water is therefore replaced by light water after a certain time of operation in such way that light water is led in and heavy water is led off. After the replacement, at least a quarter of the fuel elements of the reactor core is exchanged with the reactor pressure vessel being open. Then the light water serving as a shielding is replaced by heavy water, with the reactor pressure vessel being closed. The invention is of interest particularly for high-conversion reactors. (orig.) [de

Phytoremediation of water bodies contaminated with radioactive heavy metal

International Nuclear Information System (INIS)

Yan Zhen; Yuan Shichao; Ling Hui; Xie Shuibo

2012-01-01

The sources of the radioactive heavy metal in the water bodies were analyzed. The factors that affect phyto remediation of water contaminated with radioactive heavy metal were discussed. The plant species, mechanism and major technology of phyto remediation of water contaminated with radioactive heavy metal were particularly introduced. The prospective study was remarked. (authors)

Fuel and heavy water availability

International Nuclear Information System (INIS)

1980-01-01

The general guidelines for the Working Group's evaluation of the availability of nuclear fuel and heavy water were set at the Organizing Conference of the International Nuclear Fuel Cycle Evaluation (INFCE), which was held in Washington, United States of America, 19-21 October 1977. The agreed technical and economic scope for the evaluation was to: (1) Estimate needs for nuclear energy and correlated needs for uranium and heavy water according to different fuel cycle strategies; (2) Review uranium availability with specific regard to: Assessment of resources and production capacities; policies and incentives for encouraging exploration and production including joint ventures; marketing policies and/or guarantees of sales for companies investing in exploration and production; marketing policies and/or guarantees of supply for utilities; technical development of exploration, mining and milling methods; (3) Review heavy water availability; (4) Review thorium availability; (5) Consider special needs of developing countries. The illustrations of availability and requirements developed in this report do provide a useful framework for considering future options and alternatives for the development of nuclear power

Production of heavy water by photodesorption

International Nuclear Information System (INIS)

Gangwer, T.; Goldstein, M.K.

1976-01-01

Research has recently brought attention to the laser as a tool for isotope enrichment. So far the main thrust of this effort has been toward uranium enrichment; however, numerous successes in other areas have been demonstrated. Isotopes of boron, sulfur, chlorine, and carbon have been separated. A new technique is proposed for laser isotope enrichment. The technique, referred to as photodesorption, involves selective isotopic excitation of molecules adsorbed on a surface such that an enrichment results from subsequent physical or chemical events undergone by the excited molecules. The specific processes of concern are the physical photodesorption enrichment of heavy water from light water and tritiated water from heavy water. The ability to work directly with water molecules has significant advantages for a commercial process. A photodesorption enrichment process has been forumulated and some analyses have been performed. This process is described and some preliminary cost estimates are made which assume successful accomplishment of the major R and D objectives of the new process. The results indicate that the process has the promise of a significant reduction in the cost of heavy water and that further study is warranted

Heavy water effects on the structure, functions and behavior of biological systems

International Nuclear Information System (INIS)

Buzgariu, Wanda; Caloianu, Maria; Moldovan, Lucia; Titescu, G.

2003-01-01

The H 2 O substitution for D 2 O either in environment or in the culture medium of the living systems generates changes in their main functions and composition. In this paper some of the heavy water effects in biological systems such as structural and functional changes were reviewed: normal cell architecture alterations, cell division and membrane functions disturbance, muscular contractility and the perturbations of biological oscillators such as circadian rhythm, heart rate, respiratory cycle, tidal and ultradian rhythm. (authors)

The heavy water production plant at Arroyito, Argentina

International Nuclear Information System (INIS)

Ecabert, R.

1984-01-01

The author describes the construction of an industrial heavy water production plant (Planta Industrial de Agua Pesada, PIAP) in Argentina. The heavy water enrichment is based on a hydrogen/ammonia isotope exchange. (Auth.)

Standards for heavy water concentration determinations in light water

International Nuclear Information System (INIS)

Varlam, M.; Steflea, D.; Pavelescu, M.

1995-01-01

The paper presents a method to prepare heavy water -light water standards within the range 144 ppm - 1%. A formula for computing standards concentration based on initial concentration of D 2 O and distilled water is given

Overcoming technology - obsolescence: a case study in Heavy Water Plant

International Nuclear Information System (INIS)

Gupta, O.P.; Sonde, R.R.; Wechalekar, A.K.

2002-01-01

Ammonia based Heavy Water Plants in India are set up essentially in conjunction with fertiliser plants for the supply of feed synthesis gas. Earlier ammonia was being produced in fertiliser plants using high-pressure technology which was highly energy intensive. However with fast developments in the field of production of ammonia, fertiliser plants are switching over to low pressure technology. Ammonia based heavy water plants have to operate on pressures corresponding to that of fertiliser plants. Due to low pressures in production of ammonia, heavy water plants would also be required to operate at low pressures than the existing operating pressures. This problem was faced at Heavy Water Plant at Baroda where GSFC supplying synthesis gas switched over to low pressure technology making it imperative on the part of Heavy Water Board to carry out modification to the main plant for continued operation of Heavy Water Plant, Baroda. Anticipating similar problems due to production of ammonia at lower pressures in other fertiliser plants linked to existing Heavy Water Plants, it became necessary for HWB to develop water ammonia front end. The feed in such a case would be water instead of synthesis gas. This would enable HWB to dispense with dependence on fertiliser plants especially if grass-root ammonia based heavy water plants are to be set up. Incorporation of water ammonia front end would enable HWB to de link ammonia based heavy water plants with fertiliser plants. This paper discusses the advantage of de linking heavy water plant respective fertiliser plant by incorporating water ammonia front end and technical issues related to front end technology. A novel concept of ammonia absorption refrigeration (AAR) was considered for the process integration with the front end. The incorporation of AAR with water ammonia front-end configuration utilizes liquid ammonia refrigerant to generate refrigeration without additional energy input which otherwise would have been

Electrolytic process for upgrading heavy water (Preprint No. PD-16)

International Nuclear Information System (INIS)

Rammohan, K.; Sadhukhan, H.K.

1989-04-01

In the reactor system the heavy water gets depleted in concentration due to leakages, intermixing and vapour collection in boiler vault system etc. Electrolysis of water was used as a secondary plant to enrich the dilute heavy water produced in the primery plant by hydrogen-sulfide-water exchange process. The studies made in the development of this process for the upgrading of downgra ded heavy water by setting up a full size Electrolyser Test Assembly are discussed a nd complete design of a heavy water upgrading plant based on electrolytic process for MAPS and NAPP is described. (author). 7 refs., 5 figs

Fluoride content in water in and around heavy water plant Manuguru colony

International Nuclear Information System (INIS)

Mohapatra, C.; Dubey, S.K.; Reddy, A.R.; Ravi Kumar, T.S.P.; Selvaraj, S.

1996-01-01

Fluoride concentration in water used for human consumption has significant importance with respect to its toxic effects. Hence there was a need for analysing fluoride concentration in drinking water primarily used at Heavy water Plant, Manuguru (HWP (M)) colony and its nearby villages. We found that at HWP (M) colony there is not much variation in the fluoride concentration. However, nearby villages are having wide variation from 0.79 to 5.1 ppm. (author). 5 refs., 1 tab

Characterization and treatment options for high TOC heavy water

International Nuclear Information System (INIS)

Evans, D.; Leilabadi, A.; Rudolph, A.; Williams, D.

2007-01-01

High total organic carbon (TOC) and high conductivity contamination in heavy water feed present serious problems for the operation of heavy water upgrader facilities. The authors describe the chemical analysis of a particular batch of contaminated heavy water which had resisted standard clean-up procedures. After chemical characterization, a special clean-up plan was developed and successfully tested in the laboratory, followed by its implementation at site. (author)

Assets optimization at Heavy Water Plants

International Nuclear Information System (INIS)

Hiremath, S.C.

2006-01-01

In the world where the fittest can only survive, manufacturing and production enterprises are under intense pressure to achieve maximum efficiency in each and every field related to the ultimate production of plant. The winners will be those that use their assets, i.e men, material, machinery and money most effectively. The objective is to optimize the utilization of all plant assets-from entire process lines to individual pressure vessels, piping, process machinery, and vital machine components. Assets of Heavy Water Plants mainly consist of Civil Structures, Equipment and Systems (Mechanical, Electrical) and Resources like Water, Energy and Environment

Electrolytic separation factors for oxygen isotopes in light and heavy water solutions

International Nuclear Information System (INIS)

Gulens, J.; Olmstead, W.J.; Longhurst, T.H.; Gale, K.L.; Rolston, J.H.

1987-01-01

The electrolytic separation factor, α, has been measured for /sup 17/O and /sup 18/O at Pt and Ni anodes in both light and heavy water solutions of 6M KOH as a function of current density. For oxygen-17, isotopic separation effects were not observed, within the experimental uncertainty of +-2%, under all conditions studied. For oxygen-18, there is a small difference of 2% in α values between Pt and Ni in both light and heavy water solutions, but there is no significant difference in α values between light and heavy water solutions. In light waters solutions, the separation factor at Pt is small, α(/sup 18/O) ≤ 1.02 for i ≥ 0.1 A/cm/sub 2/. This value agrees reasonably well with theoretical estimates

Status of advanced technology and design for water cooled reactors: Heavy water reactors

International Nuclear Information System (INIS)

1989-07-01

In 1987 the IAEA established the International Working Group on Advanced Technologies for Water-Cooled Reactors (IWGATWR). Within the framework of the IWGATWR the IAEA Technical Report on Status of Advanced Technology and Design for Water Cooled Reactors, Part I: Light Water Reactors and Part II: Heavy Water Reactors, has been undertaken to document the major current activities and trends of technological improvement and development for future water reactors. Part I of the report dealing with Light Water Reactors (LWRs) was published in 1988 (IAEA-TECDOC-479). Part II of the report covers Heavy Water Reactors (HWRs) and has now been prepared. This report is based largely upon submissions from Member States. It has been supplemented by material from the presentations at the IAEA Technical Committee and Workshop on Progress in Heavy Water Reactor Design and Technology held in Montreal, Canada, December 6-9, 1988. It is hoped that this part of the report, containing the status of advanced heavy water reactor technology up to 1988 and ongoing development programmes will aid in disseminating information to Member States and in stimulating international cooperation. Refs, figs and tabs

High purity heavy water production: need for total organic carbon determination in process water streams

International Nuclear Information System (INIS)

Ayushi; Kumar, Sangita D.; Reddy, A.V.R.; Vithal, G.K.

2009-01-01

In recent times, demand for high purity heavy water (99.98% pure) in industries and laboratories has grown by manifold. Its application started in nuclear industry with the design of CANDU reactor, which uses natural uranium as fuel. In this reactor the purest grade of heavy water is used as the moderator and the primary coolant. Diverse industrial applications like fibre optics, medicine, semiconductors etc. use high purity heavy water extensively to achieve better performance of the specific material. In all these applications there is a stringent requirement that the total organic carbon content (TOC) of high purity heavy water should be very low. This is because the presence of TOC can lead to adverse interactions in different applications. To minimize the TOC content in the final product there is a need to monitor and control the TOC content at each and every stage of heavy water production. Hence a simple, rapid and accurate method was developed for the determination of TOC content in process water samples. The paper summarizes the results obtained for the TOC content in the water samples collected from process streams of heavy water production plant. (author)

assessment of heavy metals concentration in drinking water ...

African Journals Online (AJOL)

userpc

guidelines (WHO 2005). Findings suggest that continues water quality monitoring should be carried out to check the concentration levels of heavy metals in that area, to prevent them from been above the limit of WHO. Keywords: Atomic Absorption Spectrophotometers, Heavy Metals, Water, Kauru Local. Government Area.

Chemical elimination of alumina in suspension in nuclear reactors heavy water

International Nuclear Information System (INIS)

Ledoux, A.

1967-02-01

Corrosion of aluminium in contact with moderating water in nuclear reactor leads to the formation of an alumina hydrosol which can have an adverse effect on the operation of the reactor. Several physical methods have been used in an attempt to counteract this effect. The method proposed here consists in the elimination of the aluminium by dissolution and subsequent fixation in the ionic form on mixed-bed ion-exchange resin. In order to do this, the parameters and the values of these parameters most favorable to the dissolution process have been determined. If the moderator is heavy water, the deuterated acid can be prepared by converting a solution in heavy water to a salt of the acid using a deuterated cationic resin. (author) [fr

Heavy water cycle in the CANDU reactor

International Nuclear Information System (INIS)

Nanis, R.

2000-01-01

Hydrogen atom has two isotopes: deuterium 1 H 2 and tritium 1 H 3 . The deuterium oxide D 2 O is called heavy water due to its density of 1105.2 Kg/m 3 . Another important physical property of the heavy water is the low neutron capture section, suitable to moderate the neutrons into natural uranium fission reactor as CANDU. Due to the fact that into this reactor the fuel is cooled into the pressure tubes surrounded by a moderator, the usage of D 2 O as primary heat transport (PHT) agent is mandatory. Therefore a large amount of heavy water (approx. 500 tons) is used in a CANDU reactor. Being a costly resource - it represents 20% of the initial plant capital cost, D 2 O management is required to preserve it. (author)

Heavy water radiolysis and chemistry control of the Fugen Nuclear Power Station

International Nuclear Information System (INIS)

Ibuki, Y.; Kitabata, T.; Kato, T.

1989-01-01

A computer analysis for heavy water radiolysis clarified the mechanism of the heavy water radiolysis rate change with impurities in the heavy water and cover gas, helium. The mechanism is supported by over ten years' operational data of the heavy water radiolysis in the Fugen nuclear power station. (author)

Impact of different moderator ratios with light and heavy water cooled reactors in equilibrium states

International Nuclear Information System (INIS)

Permana, Sidik; Takaki, Naoyuki; Sekimoto, Hiroshi

2006-01-01

As an issue of sustainable development in the world, energy sustainability using nuclear energy may be possible using several different ways such as increasing breeding capability of the reactors and optimizing the fuel utilization using spent fuel after reprocessing as well as exploring additional nuclear resources from sea water. In this present study the characteristics of light and heavy water cooled reactors for different moderator ratios in equilibrium states have been investigated. The moderator to fuel ratio (MFR) is varied from 0.1 to 4.0. Four fuel cycle schemes are evaluated in order to investigate the effect of heavy metal (HM) recycling. A calculation method for determining the required uranium enrichment for criticality of the systems has been developed by coupling the equilibrium fuel cycle burn-up calculation and cell calculation of SRAC 2000 code using nuclear data library from the JENDL 3.2. The results show a thermal spectrum peak appears for light water coolant and no thermal peak for heavy water coolant along the MFR (0.1 ≤ MFR ≤ 4.0). The plutonium quality can be reduced effectively by increasing the MFR and number of recycled HM. Considering the effect of increasing number of recycled HM; it is also effective to reduce the uranium utilization and to increase the conversion ratio. trans-Plutonium production such as americium (Am) and curium (Cm) productions are smaller for heavy water coolant than light water coolant. The light water coolant shows the feasibility of breeding when HM is recycled with reducing the MFR. Wider feasible area of breeding has been obtained when light water coolant is replaced by heavy water coolant

Assessment of heavy metal pollution in drinking water due to mining ...

African Journals Online (AJOL)

Mining and smelting activities are the main causes for the increasing pollution of heavy metals from water sources. The toxicity of these heavy metals from the mining, milling and smelting companies can cause harmful and even lethal effects on the human health. The objective of this study was to investigate the level of As, ...

Winter Maintenance Wash-Water Heavy Metal Removal Pilot Scale Evaluation

Directory of Open Access Journals (Sweden)

Christopher M. Miller

2016-01-01

Full Text Available To encourage sustainable engineering practices, departments of transportation are interested in reusing winter maintenance truck wash water as part of their brine production and future road application. Traffic-related metals in the wash water, however, could limit this option. The objective of this work was to conduct a pilot scale evaluation of heavy metal (copper, zinc, iron, and lead removal in a filtration unit (maximum flow rate of 45 L/minute containing proprietary (MAR Systems Sorbster® media. Three different trials were conducted and approximately 10,000 L of wash water collected from a winter maintenance facility in Ohio was treated with the pilot unit. Lab studies were also performed on six wash-water samples from multiple facilities to assess particle size removal and estimate settling time as a potential removal mechanism during wash-water storage. Pilot unit total metal removal efficiencies were 79%, 77%, 63%, and 94% for copper, zinc, iron, and lead, respectively. Particle settling calculation estimates for copper and zinc show that 10 hours in storage can also effectively reduce heavy metal concentrations in winter maintenance wash water in excess of 70%. These pilot scale results show promise for reducing heavy metal concentrations to an acceptable level for reuse.

Assessment of heavy metals in loose deposits in drinking water distribution system.

Science.gov (United States)

Liu, Quanli; Han, Weiqiang; Han, Bingjun; Shu, Min; Shi, Baoyou

2018-06-09

Heavy metal accumulation and potential releases from loose deposits in drinking water distribution system (DWDS) can have critical impacts on drinking water safety, but the associated risks have not been sufficiently evaluated. In this work, the potential biological toxicity of heavy metals in loose deposits was calculated based on consensus-based sediment quality guidelines, and the effects of some of the main water quality parameters, such as the pH and bicarbonate and phosphate content, on the release behaviors of pre-accumulated heavy metals were investigated. The results showed that heavy metals (Cu, As, Cr, Pb, and Cd) significantly accumulated in all the samples, but the contents of the heavy metals were multiple magnitudes lower than the Fe and Mn contents. The potential biotoxicity of As and Cu was relatively high, but the biotoxicity of Cd was negligible. The water quality can significantly influence the release of heavy metals from loose deposits. As the pH increased from 7.0 to 9.0, the release of As and Cr obviously increased. The release of As, Cu, Pb, and Cr also accelerated with the addition of phosphate (from 1 to 5 mg/L). In contrast to the trends for the pH and phosphate, variations in the bicarbonate content did not have a significant influence on the release of As and Cr. The release ratios of heavy metals in the samples were very low, and there was not a correlation between the release rate of the heavy metals in the loose deposits and their potential biotoxicity.

Heavy water isotopic rectification in the ''ORPHEE'' reactor. SACLAY studies Centre

International Nuclear Information System (INIS)

Lejeune, P.; Breant, P.

1993-01-01

ORPHEE reactor supplies neutron beams, which are got back in a heavy water reflector. The neutron beams intensity depends on the reflector quality which is determined by the isotopic content of the heavy water. The deuterium submitted to core irradiation changes in radioactive tritium which must be eliminated largely for reasons of safety. The column must keep the heavy water isotopic content of the reflector to a value higher than 99.8% by eliminating light water by fractional distillation or rectification. This column is also used for the tritium elimination of heavy water. 13 figs

Critical heat flux experiments in a circular tube with heavy water and light water. (AWBA Development Program)

International Nuclear Information System (INIS)

Williams, C.L.; Beus, S.G.

1980-05-01

Experiments were performed to establish the critical heat flux (CHF) characteristics of heavy water and light water. Testing was performed with the up-flow of heavy and of light water within a 0.3744 inch inside diameter circular tube with 72.3 inches of heated length. Comparisons were made between heavy water and light water critical heat flux levels for the same local equilibrium quality at CHF, operating pressure, and nominal mass velocity. Results showed that heavy water CHF values were, on the average, 8 percent below the light water CHF values

Process for the preparation of ammonia and heavy water

International Nuclear Information System (INIS)

Mandrin, C.

1980-01-01

A process for the production of ammonia and heavy water comprises the steps of enriching a flow of water with deuterium in a monothermal isotropic process; supplying a first portion of the deuterium-enriched water to a heavy water preparation plant to produce heavy water and hydrogen; storing a second portion of the deuterium-enriched water substantially without interruption during the colder half of a year; electrolytically dissociating the stored deuterium-enriched water substantially without interruption during the wamer half of a year to form hydrogen; storing a portion of the electrolytically-produced hydrogen during said warmer half of a year while supplying the remainder to a synthesis circuit of a synthesizing plant and subsequently supplying the stored hydrogen to the synthesis circuit during said colder half of a year; removing some of the synthesis gas mixture from the synthesis circuit of the synthesizing plant; burning the removed synthesis gas mixture with air to produce a mixture consisting mainly of water and nitrogen; thereafter condensing and separating the water from the mixture of water and nitrogen; supplying the nitrogen of the mixture of water and nitrogen, the hydrogen from the heavy water preparation plant and the electrolytically-produced hydrogen to the synthesis circuit of the synthesizing plant to produce ammonia; and collecting deuterium-depleted water resulting from said burning step and feeding the collected deuterium-depleted water into the monothermal process

Removal of Heavy Metals from Drinking Water by Magnetic Carbon Nanostructures Prepared from Biomass

OpenAIRE

Muneeb Ur Rahman Khattak, Muhammad; Zahoor, Muhammad; Muhammad, Bakhtiar; Khan, Farhat Ali; Ullah, Riaz; AbdEI-Salam, Naser M.

2017-01-01

Heavy metals contamination of drinking water has significant adverse effects on human health due to their toxic nature. In this study a new adsorbent, magnetic graphitic nanostructures were prepared from watermelon waste. The adsorbent was characterized by different instrumental techniques (surface area analyzer, FTIR, XRD, EDX, SEM, and TG/DTA) and was used for the removal of heavy metals (As, Cr, Cu, Pb, and Zn) from water. The adsorption parameters were determined for heavy metals adsorpti...

Heavy water at Trail, British Columbia

International Nuclear Information System (INIS)

Arsenault, J.E.

2006-01-01

Today Canada stands on the threshold of a nuclear renaissance, based on the CANDU reactor family, which depends on heavy water as a moderator and for cooling. Canada has a long history with heavy water, with commercial interests beginning in 1934, a mere two years after its discovery. At one time Canada was the world's largest producer of heavy water. The Second World War stimulated interest in this rather rare substance, such that the worlds largest supply (185 kg) ended up in Canada in 1942 to support nuclear research work at the Montreal Laboratories of the National Research Council. A year later commercial production began at Trail, British Columbia, to support work that later became known as the P-9 project, associated with the Manhattan Project. The Trail plant produced heavy water from 1943 until 1956, when it was shut down. During the war years the project was so secret that Lesslie Thomson, Special Liaison Officer reporting on nuclear matters to C.D. Howe, Minister of Munitions and Supply, was discouraged from visiting Trail operations. Thomson never did visit the Trail facility during the war. In 2005 the remaining large, tall concrete exchange tower was demolished at a cost of about $2.4 million, about the same as it cost to construct the facility about 60 years ago. Thus no physical evidence remains of this historic facility and another important artifact from Canada's nuclear history has disappeared forever. It is planned to place a plaque at the site at some point in the future. (author)

Heavy water at Trail, British Columbia

Energy Technology Data Exchange (ETDEWEB)

Arsenault, J.E. [Ontario (Canada)

2006-09-15

Today Canada stands on the threshold of a nuclear renaissance, based on the CANDU reactor family, which depends on heavy water as a moderator and for cooling. Canada has a long history with heavy water, with commercial interests beginning in 1934, a mere two years after its discovery. At one time Canada was the world's largest producer of heavy water. The Second World War stimulated interest in this rather rare substance, such that the worlds largest supply (185 kg) ended up in Canada in 1942 to support nuclear research work at the Montreal Laboratories of the National Research Council. A year later commercial production began at Trail, British Columbia, to support work that later became known as the P-9 project, associated with the Manhattan Project. The Trail plant produced heavy water from 1943 until 1956, when it was shut down. During the war years the project was so secret that Lesslie Thomson, Special Liaison Officer reporting on nuclear matters to C.D. Howe, Minister of Munitions and Supply, was discouraged from visiting Trail operations. Thomson never did visit the Trail facility during the war. In 2005 the remaining large, tall concrete exchange tower was demolished at a cost of about $2.4 million, about the same as it cost to construct the facility about 60 years ago. Thus no physical evidence remains of this historic facility and another important artifact from Canada's nuclear history has disappeared forever. It is planned to place a plaque at the site at some point in the future. (author)

Removal of Heavy Metals from Drinking Water by Magnetic Carbon Nanostructures Prepared from Biomass

Directory of Open Access Journals (Sweden)

Muhammad Muneeb Ur Rahman Khattak

2017-01-01

Full Text Available Heavy metals contamination of drinking water has significant adverse effects on human health due to their toxic nature. In this study a new adsorbent, magnetic graphitic nanostructures were prepared from watermelon waste. The adsorbent was characterized by different instrumental techniques (surface area analyzer, FTIR, XRD, EDX, SEM, and TG/DTA and was used for the removal of heavy metals (As, Cr, Cu, Pb, and Zn from water. The adsorption parameters were determined for heavy metals adsorption using Freundlich and Langmuir isotherms. The adsorption kinetics and effect of time, pH, and temperature on heavy metal ions were also determined. The best fits were obtained for Freundlich isotherm. The percent adsorption showed a decline at high pH. Best fit was obtained with second-order kinetics model for the kinetics experiments. The values of ΔH° and ΔG° were negative while that of ΔS° was positive. The prepared adsorbent has high adsorption capacities and can be efficiently used for the removal of heavy metals from water.

Method and apparatus for enrichment or upgrading heavy water

International Nuclear Information System (INIS)

Butler, J.P.; Hammerli, M.

1979-01-01

A method and apparatus for upgrading and final enrichment of heavy water are described, comprising means for contacting partially enriched heavy water feed in a catalyst column with hydrogen gas (essentially D 2 ) originating in an electrolysis cell so as to enrich the feed water with deuterium extracted from the electrolytic hydrogen gas and means for passing the deuterium enriched water to the electrolysis cell. (author)

The Canadian heavy water situation

International Nuclear Information System (INIS)

Dahlinger, A.

The Canadian heavy water industry is analyzed. Supply and demand are predicted through 1985. Pricing is broken down into components. Backup R and D contributes greatly to process improvements. (E.C.B.)

Tritium separation from heavy water using electrolysis

International Nuclear Information System (INIS)

Ogata, Y.; Sakuma, Y.; Ohtani, N.; Kodaka, M.

2001-01-01

A tritium separation from heavy water by the electrolysis using a solid polymer electrode (SPE) was specified on investigation. The heavy water (∼10 Bq g -1 ) and the light water (∼70 Bq g -1 ) were electrolysed using an electrolysis device (Tripure XZ001, Permelec Electrode Ltd.) with the SPE layer. The cathode was made of stainless steel (SUS314). The electrolysis was carried out at 20 A x 60 min, with the electrolysis temperature at 10, 20, or 30degC, and 15 A x 80 min at 5degC. The produced hydrogen and oxygen gases were recombined using a palladium catalyst (ND-101, N.E. Chemcat Ltd.) with nitrogen gas as a carrier. The activities of the water in the cell and of the recombined water were analyzed using a liquid scintillation counter. The electrolysis potential to keep the current 20 A was 2-3 V. The yields of the recombined water were more than 90%. The apparent separation factors (SF) for the heavy water and the light water were ∼2 and ∼12, respectively. The SF value was in agreement with the results in other work. The factors were changed with the cell temperature. The electrolysis using the SPE is applicable for the tritium separation, and is able to perform the small-scale apparatus at the room temperature. (author)

Improved method of degassing of feed water at Heavy Water Plant, Kota

International Nuclear Information System (INIS)

Krishnan, G.K.; Agrawal, A.K.

1994-01-01

Heavy Water Plant (Kota) processes 450 MT/hr of feed water as the source of deuterium using water/hydrogen sulphide exchange process for the production of heavy water. Plant design has limited the ingress of dissolved oxygen in feed water to 0.2 ppm. However, even this low limit on dissolved oxygen has been found unacceptable during plant operation as over an operational period of 3-4 years accumulation of sulphur due to oxidation of hydrogen sulphide on exchange tower trays poses major operational problems. This paper discusses the results of nitrogen injection used for reducing the ingress of dissolved oxygen in the feed water system of the plant. (author)

High resolution conductometry for isotopic assay of deuterium in mixtures of heavy water and light water

International Nuclear Information System (INIS)

Ananthanarayanan, R.; Sahoo, P.; Murali, N.

2014-01-01

A PC based high resolution conductivity monitoring technique has been deployed for determination of isotopic purity of heavy water in samples containing heavy water and light water mixtures using pulsating sensor based conductivity monitoring instrument. The technique involves accurate determination of conductivities of a series of specially treated heavy water and light water mixtures of various compositions at a constant solution temperature. The shift in conductivity (Δκ), which is the difference between conductivities of composite mixture after and before the formation of a typical complex compound (boric acid–mannitol complex in this case), shows a smooth and reproducible decreasing trend with increase in percentage composition of heavy water. This relation, which is obtained by appropriate calibration, is used in the software program for direct display of isotopic purity of heavy water. The technique is examined for determination of percentage composition of heavy water in the entire range of concentration (0-100 %) with reasonable precision (relative standard deviation, RSD ≤1.5 %). About 1 mL of sample is required for each analysis and analysis is completed within a couple of minutes after pretreatment of sample. The accuracy in measurement is ≤1.75 %. (author)

Canadian heavy water production - 1970 to 1980

International Nuclear Information System (INIS)

Galley, M.R.

1981-01-01

In the last decade, heavy water production in Canada has progressed from the commissioning of a single unit plant in Nova Scotia to a major production industry employing 2200 persons and operating three plants with an aggregate annual production capability in excess of 1800 Mg. The decade opened with an impending crisis in the supply of heavy water due to failure of the first Glace Bay Heavy Water Plant and difficulty in commissioning the second Canadian plant at Port Hawkesbury. Lessons learned at this latter plant were applied to the Bruce plant where the first two units were under construction. When the Bruce units were commissioned in 1973 the rate of approach to design production rates was much improved, renewing confidence in Canada's ability to succeed in large scale heavy water production. In the early 1970's a decision was made to rehabilitate the Glace Bay plant using a novel flowsheet and this rebuilt plant commenced production in 1976. The middle of the decade was marked by two main events: changes in ownership of the operating plants and initiation of a massive construction program to support the forecast of a rapidly expanding CANDU power station construction program. New production units embodying the best features of their predecessors were committed at Bruce by Ontario Hydro and at La Prade, Quebec, by AECL. The high growth rate in electrical demand did not continue and some new plant construction was curtailed. The present installed production capacity will now probably be adequate to meet anticipated demand for the next decade. Canadian plants have now produced more than 7800 Mg of heavy water at a commercially acceptable cost and with a high degree of safety and compliance with appropriate environmental regulations

Tritium concentration in the heavy water upgrading plants

International Nuclear Information System (INIS)

Croitoru, C.; Pop, F.; Titescu, Gh.; Dumitrescu, M.; Ciortea, C.; Stefanescu, I.; Peculea, M.; Pitigoi, Gh.; Trancota, D. . E-mail of corresponding author: croitoru@icsi.ro; Croitoru, C.)

2005-01-01

In the course of time heavy water used in CANDU nuclear power plants, as moderator or coolant, degrades, as a result of its impurification with light water and tritium. Concentration diminution below 99.8% mol for moderator and 99.75% mol for coolant causes an inefficient functioning of CANDU reactor. By isotopic distillation, light water is removed. Simultaneously tritium concentration takes place. The heavy water upgrading plant from Cernavoda is an isotopic separation cascade with two stages. The paper presents, for this plant, a theoretical study of the tritium concentration. (author)

High converter pressurized water reactor with heavy water as a coolant

International Nuclear Information System (INIS)

Ronen, Y.; Reyev, D.

1983-01-01

There is an increasing interest in water breeder and high converter reactors. The increase in the conversion ratio of these reactors is obtained by hardening the neutron spectrum achieved by tightening the reactor's lattice. Another way of hardening the neutron spectrum is to replace the light water with heavy water. Two pressurized water reactor fuel cycles that use heavy water as a coolant are considered. The first fuel cycle is based on plutonium and depleted uranium, and the second cycle is based on plutonium and enriched uranium. The uranium ore and separative work unit (SWU) requirements are calculated as well as the fuel cycle cost. The savings in uranium ore are about40 and 60% and about40% in SWU for both fuel cycles considered

Electromagnetic radiation during electrolysis of heavy water

International Nuclear Information System (INIS)

Koval'chuk, E.P.; Yanchuk, O.M.; Reshetnyak, O.V.

1994-01-01

The radiation in the visible and ultraviolet spectral regions during electrolysis of heavy water on nickel and palladium cathodes was determined for the first time. A sharp jump of the intensity photon flow was observed at a current density of higher than 125 mA/cm 2 . A hypothesis about the relation of the electrochemiluminescence phenomenon during electrolysis of heavy water with the formation of fresh surfaces in consequence of the hydrogenous corrosion of the cathode material is formulated. ((orig.))

Eliminating Heavy Metals from Water with NanoSheet Minerals as Adsorbents

Directory of Open Access Journals (Sweden)

Shaoxian Song

2017-12-01

Full Text Available Heavy metals usually referred to those with atomic weights ranging from 63.5 to 200.6. Because of natural-mineral dissolution and human activities such as mining, pesticides, fertilizer, metal planting and batteries manufacture, etc., these heavy metals, including zinc, copper, mercury, lead, cadmium and chromium have been excessively released into water courses, like underground water, lake and river, etc. The ingestion of the heavy metals-contaminated water would raise serious health problems to human beings even at a low concentration. For instance, lead can bring human beings about barrier to the normal function of kidney, liver and reproductive system, while zinc can cause stomach cramps, skin irritations, vomiting and anemia. Mercury is a horrible neurotoxin that may result in damages to the central nervous system, dysfunction of pulmonary and kidney, chest and dyspnea. Chromium (VI has been proved can cause many diseases ranging from general skin irritation to severe lung carcinoma. Accordingly, the World Health Organization announced the maximum contaminant levels (MCL for the heavy metals in drinking water. There are numerous processes for eliminating heavy metals from water in order to provide citizens safe drinking water, including precipitation, adsorption, ion exchange, membrane separation and biological treatment, etc. Adsorption is considered as a potential process for deeply removing heavy metals, in which the selection of adsorbents plays a predominant role. Nano-sheet minerals as the adsorbents are currently the hottest researches in the field. They are obtained from layered minerals, such as montmorillonite, graphite and molybdenite, through the processing of intercalation, electrochemical and mechanical exfoliation, etc. Nano-sheet minerals are featured by their large specific surface area, relatively low costs and active adsorbing sites, leading to be effective and potential adsorbents for heavy metals removal from water

Improved method of degassing of feed water at Heavy Water Plant, Kota

Energy Technology Data Exchange (ETDEWEB)

Krishnan, G K; Agrawal, A K [Heavy Water Plant, Kota (India)

1994-06-01

Heavy Water Plant (Kota) processes 450 MT/hr of feed water as the source of deuterium using water/hydrogen sulphide exchange process for the production of heavy water. Plant design has limited the ingress of dissolved oxygen in feed water to 0.2 ppm. However, even this low limit on dissolved oxygen has been found unacceptable during plant operation as over an operational period of 3-4 years accumulation of sulphur due to oxidation of hydrogen sulphide on exchange tower trays poses major operational problems. This paper discusses the results of nitrogen injection used for reducing the ingress of dissolved oxygen in the feed water system of the plant. (author). 1 fig.

Safety system in a heavy water detritiation plant

International Nuclear Information System (INIS)

Balteanu, O.; Stefan, I.; Retevoi, C.

2003-01-01

In a CANDU 6 type reactor a quantity of 55·10 15 Bq/year of tritium is generated, 95% being in the D 2 O moderator which can achieve a radioactivity of 2.5-3.5·10 12 Bq/kg. Tritium in heavy water contributes with 30-50% to the doses received by operation personnel and up to 20% to the radioactivity released in the environment. The large quantity of heavy water used in this type of reactors (500 tones) make storage very difficult, especially for environment. The extraction of tritium from tritiated heavy water of CANDU reactors solve the following problems: the radiation level in the operation area, the costs of maintenance and repair reduction due to reduction of personnel protection measures, the increase of NPP utilisation factor by shutdown time reduction for maintenance and repair, use the extracted tritium for fusion reactors and not for the last, lower costs and risk for storage heavy water waste. Heavy water detritiation methods, which currently are used in the industrial or experimental plant, are based on catalytic isotope exchange or electrolysis followed cryogenic distillation or permeation. The technology developed at Institute of Cryogenics and Isotope Separation is based upon catalytic exchange between tritiated water and deuterium, followed by cryogenic distillation of hydrogen isotopes. The nature of the fluids that are processed in detritiation requires the operation of the plant in safety conditions. The paper presents the safety system solution chose in order to solve this task, as well as a simulation of an incident and safety system response. The application software is using LabView platform that is specialised on control and factory automation applications. (author)

The effect of heavy water reactors and liquid fuel reactors on the long-term development of nuclear energy

International Nuclear Information System (INIS)

Brand, P.; Wiechers, W.K.

1974-01-01

The effects of the rates at which various combinations of power reactor types are installed on the long-range (to the year 2040) uranium and plutonium inventory requirements are examined. Consideration is given to light water reactors, fast breeder reactors, high temperature gas-cooled reactors, heavy water reactors, and thermal breeder reactors, in various combinations, and assuming alternatively a 3% and a 5% growth in energy demand

Modification of water treatment plant at Heavy Water Plant (Kota)

International Nuclear Information System (INIS)

Gajpati, C.R.; Shrivastava, C.S.; Shrivastava, D.C.; Shrivastava, J.; Vithal, G.K.; Bhowmick, A.

2008-01-01

Heavy Water Production by GS process viz. H 2 S - H 2 O bi-thermal exchange process requires a huge quantity of demineralized (DM) water as a source of deuterium. Since the deuterium recovery of GS process is only 18-19%, the water treatment plant (WTP) was designed and commissioned at Heavy Water Plant (Kota) to produce demineralized water at the rate of 680 m 3 /hr. The WTP was commissioned in 1980 and till 2005; the plant was producing DM water of required quality. It was having three streams of strong cation resin, atmospheric degasser and strong anion exchange resin with co-current regeneration. In 2001 a new concept of layered bed resin was developed and engineered for water treatment plant. The concept was attractive in terms of saving of chemicals and thus preservation of environment. Being an ISO 9000 and ISO 14000 plant, the modification of WTP was executed in 2005 during major turn around. After modification, a substantial amount of acid and alkali is saved

A review of the UKAEA interest in heavy water reactors

International Nuclear Information System (INIS)

Symes, R.J.

1983-01-01

The chapter commences with a brief account of the history of heavy water production and then begins the story of the British use of this moderator in power reactors. This is equated with the introduction and development of the tube reactor as a distinct and important form of reactor construction in contrast with the perhaps better known vessel design that has tended to dominate reactor engineering to date. The account thus includes a succession of reactor designs including the gas and steam cooled heavy water systems in addition to the steam-generating heavy water reactor. The SGHWR was demonstrated by the construction of a substantial prototype, which continues in operation as a flexible and reliable electricity-generating plant. It was also, for a time, identified as the system to be used for Britain's third reactor programme. Today the successful Canadian CANDU power reactors represent the only penetration of heavy water reactor technology into large scale electricity generation. The range of research and experimental reactors using heavy water in their cores is reviewed. (author)

Direction of Heavy Water Projects

International Nuclear Information System (INIS)

1984-07-01

Summary of the activities performed by the Heavy Water Projects Direction of the Argentine Atomic Energy Commission from 1950 to 1983. It covers: historical data; industrial plant (based on ammonia-hydrogen isotopic exchange); experimental plant (utilizing hydrogen sulfides-water process); Module-80 plant (2-3 tons per year experimental plant with national technology) and other related tasks on research and development (E.A.C.) [es

Decontamination of the RA reactor heavy water system, Annex 9

International Nuclear Information System (INIS)

Maksimovic, Z.B.; Nikolic, R.M.; Marinkovic, M.D.; Jelic, Lj.M.

1963-01-01

Both stainless steel and aluminium parts of the RA reactor heavy water system system were decontaminated as well as the heavy water itself. System was contaminated with 60 Co. Decontamination factor was determined by activity measurements during distillation. Concentration of the corrosion products in the heavy water was measured by spectrochemical analysis, and found to be 0.1 - 1 mg/l. Chemical analyses of the aluminium and stainless steel surfaces showed that cobalt was adsorbed on the aluminium oxide layer. Water solution of 7%H 3 PO 4 + 2% CrO 3 was used for decontamination of the heavy water system and distillation device. This was found to be the most efficient solvent which does not affect stainless steel corrosion. Decontamination factors achieved were from 60 - 100. Decontamination results enabled determining the distribution of cobalt in the system: 10 Ci on the stainless steel parts, 50 Ci in the heavy water; and above 600 Ci on the fuel and experimental channels. Specific activity of 60 Co was calculated to be 15 Ci/g on the reactor channels, 8 Ci/g on the stainless steel parts and 3 Ci/g in the heavy water. Decontamination of the aluminium parts was not done because it was considered it could initiate corrosion. Since the efficiency of distillation is increased it was expected that permanent distillation would remove most of the activity in the reactor channels

Performance of refractometry in quantitative estimation of isotopic concentration of heavy water in nuclear reactor

International Nuclear Information System (INIS)

Dhole, K.; Roy, M.; Ghosh, S.; Datta, A.; Tripathy, M.K.; Bose, H.

2013-01-01

Highlights: ► Rapid analysis of heavy water samples, with precise temperature control. ► Entire composition range covered. ► Both variations in mole and wt.% of D 2 O in the heavy water sample studied. ► Standard error of calibration and prediction were estimated. - Abstract: The method of refractometry has been investigated for the quantitative estimation of isotopic concentration of heavy water (D 2 O) in a simulated water sample. Feasibility of refractometry as an excellent analytical technique for rapid and non-invasive determination of D 2 O concentration in water samples has been amply demonstrated. Temperature of the samples has been precisely controlled to eliminate the effect of temperature fluctuation on refractive index measurement. The method is found to exhibit a reasonable analytical response to its calibration performance over the purity range of 0–100% D 2 O. An accuracy of below ±1% in the measurement of isotopic purity of heavy water for the entire range could be achieved

Isotope effect in heavy/light water suspensions of optically active gold nanoparticles

Science.gov (United States)

Kutsenko, V. Y.; Artykulnyi, O. P.; Petrenko, V. I.; Avdeev, M. V.; Marchenko, O. A.; Bulavin, L. A.; Snegir, S. V.

2018-04-01

Aqueous suspensions of optically active gold nanoparticles coated with trisodium citrate were synthesized in light (H2O) water and mixture of light and heavy (H2O/D2O) water using the modified Turkevich protocol. The objective of the paper was to verify sensitivity of neutron scattering methods (in particular, neutron reflectometry) to the potential isotope H/D substitution in the stabilizing organic shell around particles in colloidal solutions. First, the isotope effect was studied with respect to the changes in the structural properties of metal particles (size, shape, crystalline morphology) in solutions by electron microscopy including high-resolution transmission electron microscopy from dried systems. The structural factors determining the variation in the adsorption spectra in addition to the change in the optical properties of surrounding medium were discussed. Then, neutron reflectometry was applied to the layered nanoparticles anchored on a silicon wafer via 3-aminopropyltriethoxysilane molecules to reveal the presence of deuterated water molecules in the shell presumably formed by citrate molecules around the metallic core.

Consequences of potential accidents in heavy water plants

International Nuclear Information System (INIS)

Croitoru, C.; Lazar, R.E.; Preda, I.A.; Dumitrescu, M.

2002-01-01

Heavy water plants achieve the primary isotopic concentration by H 2 O-H 2 S chemical exchange. In these plants are stored large quantities of hydrogen sulphide (high toxic, corrosive, flammable and explosive) maintained in process at relative high temperatures and pressures. It is required an assessment of risks associated with the potential accidents. The paper presents adopted model for quantitative consequences assessment in heavy water plants. Following five basic steps are used to identify the risks involved in plants operation: hazard identification, accident sequences development, H 2 S emissions calculus, dispersion analyses and consequences determination. A brief description of each step and some information from risk assessment for our heavy water pilot plant are provided. Accident magnitude, atmospheric conditions and population density in studied area were accounted for consequences calculus. (author)

Water conservation by 3 R's - case histories of Heavy Water Plants

International Nuclear Information System (INIS)

Agarwal, A.K.; Hiremath, S.C.

2005-01-01

The basics of water conservation revolve around three R's of Reduce, Recycle, and Reuse. The Heavy Water Plants are an excellent example of water savings, and these case studies will be of interest to the chemical industry. The issues involved with water conservation and re-use in different Heavy Water Plants are of different nature. In H 2 S-H 2 O process plants the water consumption has been substantially decreased as compared to the design water needs. To quote the figures HWP (Kota) was designed to consume 2280 m 3 /hr water, which included 453 m 3 /hr water as feed for deuterium extraction. Today the plant operates with only 1250 m 3 /hr water while processing 500 m 3 /hr feed; and is headed to decrease the total water consumption to 700 m 3 /hr. Similarly at HWP (Manuguru) the design had provided 5600 m 3 /hr water consumption, which is today operating with only 1750 m 3 /hr and poised to operate with 1600 m 3 /hr. The issues of water conservation in Ammonia Hydrogen exchange plants have an additional dimension since water losses mean direct loss of heavy water production. In adjoining ammonia plants deuterium shifts to steam in the reformer and shift converter, and this excess steam is condensed as rich condensate. It becomes incumbent on the fertilizer plant to maintain a tight discipline for conserving and re-using the rich condensate so that deuterium concentration in the synthesis gas is maintained. Efforts are also underway to utilize rich condensate of GSFC in the newly developed technology of water ammonia exchange at HWP (Baroda) and we are targeting 20% production gains by implementation of this scheme and with no increase in the pollution load. These case histories will be of interest to Chemical Process Industry. (author)

Possibilities for reorientation the activity of heavy water plants

International Nuclear Information System (INIS)

Pop, F.; Croitoru, C.; Titescu, Gh.; Stefanescu, I.; Hodor, I.; Cuna, S. . E-mail of corresponding author: pop.floarea@icsi.ro; Pop, F.)

2005-01-01

In Romania heavy water is produced by H 2 O-H 2 S chemical exchange (GS process) and by water distillation, simultaneously working two lines. The distillation plants have high separation capacity, a distillation line being able to concentrate water from two GS lines. The paper presents data regarding possibilities to use one distillation line for oxygen 18 production, as pre-concentrates or finite products. Using a simulation program it was calculated oxygen 18 concentration in heavy water produced, maximum 18 O concentration of pre-concentrate obtained on distillation line and the separation cascade dimensions for obtain 95% 18 O, with first and second stage having same dimensions like a distillation plant from Romanian heavy water factory. Oxygen-18 separation factor is much lower than deuterium separation factor. For this reason, oxygen-18 is a very expensive product. (author)

Determination of selected heavy metals in inland fresh water of ...

African Journals Online (AJOL)

Agadaga

Key words: Heavy metals, freshwater, concentrations, quality, variation, distribution. ... prevalence of heavy metals in inland water of lower River. Niger drain are scarce ..... Niger waters at Ajaokuta were found to be low and within guideline.

Instrumentation and signal processing for the detection of heavy water using off axis-integrated cavity output spectroscopy technique

Science.gov (United States)

Gupta, A.; Singh, P. J.; Gaikwad, D. Y.; Udupa, D. V.; Topkar, A.; Sahoo, N. K.

2018-02-01

An experimental setup is developed for the trace level detection of heavy water (HDO) using the off axis-integrated cavity output spectroscopy technique. The absorption spectrum of water samples is recorded in the spectral range of 7190.7 cm-1-7191.5 cm-1 with the diode laser as the light source. From the recorded water vapor absorption spectrum, the heavy water concentration is determined from the HDO and water line. The effect of cavity gain nonlinearity with per pass absorption is studied. The signal processing and data fitting procedure is devised to obtain linear calibration curves by including nonlinear cavity gain effects into the calculation. Initial calibration of mirror reflectivity is performed by measurements on the natural water sample. The signal processing and data fitting method has been validated by the measurement of the HDO concentration in water samples over a wide range from 20 ppm to 2280 ppm showing a linear calibration curve. The average measurement time is about 30 s. The experimental technique presented in this paper could be applied for the development of a portable instrument for the fast measurement of water isotopic composition in heavy water plants and for the detection of heavy water leak in pressurized heavy water reactors.

Development and implementation of the heavy water program at Bruce Power

International Nuclear Information System (INIS)

Davloor, R.; Bourassa, C.

2014-01-01

Bruce Power operates 8 pressurized heavy water reactor units requiring more than 6000 mega grams (Mg) of heavy water. A Heavy Water Management Program that has been developed to administer this asset over the past 3 years. Through a corporate management system the Program provides governance, oversight and support to the stations. It is implemented through organizational structure, program and procedure documents and an information management system that provides benchmarked metrics, business intelligence and analytics for decision making and prediction. The program drives initiatives such as major maintenance activities, capital programs, detritiation strategies and ensures heavy water systems readiness for outages and rehabilitation of units. (author)

Development and implementation of the heavy water program at Bruce Power

Energy Technology Data Exchange (ETDEWEB)

Davloor, R.; Bourassa, C., E-mail: ram.davloor@brucepower.com, E-mail: carl.bourassa@brucepower.com [Bruce Power, Tiverton, ON (Canada)

2014-07-01

Bruce Power operates 8 pressurized heavy water reactor units requiring more than 6000 mega grams (Mg) of heavy water. A Heavy Water Management Program that has been developed to administer this asset over the past 3 years. Through a corporate management system the Program provides governance, oversight and support to the stations. It is implemented through organizational structure, program and procedure documents and an information management system that provides benchmarked metrics, business intelligence and analytics for decision making and prediction. The program drives initiatives such as major maintenance activities, capital programs, detritiation strategies and ensures heavy water systems readiness for outages and rehabilitation of units. (author)

Graphite-moderated and heavy water-moderated spectral shift controlled reactors

International Nuclear Information System (INIS)

Alcala Ruiz, F.

1984-01-01

It has been studied the physical mechanisms related with the spectral shift control method and their general positive effects on economical and non-proliferant aspects (extension of the fuel cycle length and low proliferation index). This methods has been extended to non-hydrogenous fuel cells of high moderator/fuel ratio: heavy water cells have been con- trolled by graphite rods graphite-moderated and gas-cooled cells have been controlled by berylium rods and graphite-moderated and water-cooled cells have been controlled by a changing mixture of heavy and light water. It has been carried out neutron and thermal analysis on a pre design of these types of fuel cells. We have studied its neutron optimization and their fuel cycles, temperature coefficients and proliferation indices. Finally, we have carried out a comparative analysis of the fuel cycles of conventionally controlled PWRs and graphite-moderated, water-cooled and spectral shift controlled reactors. (Author) 71 refs

Effect of resuspension on the release of heavy metals and water chemistry in anoxic and oxic sediments

Energy Technology Data Exchange (ETDEWEB)

Hwang, Kyung-Yup; Kim, Hong-Seok; Hwang, Inseong [School of Civil and Environmental Engineering, Pusan National University, Busan (Korea, Republic of)

2011-10-15

Two types of river sediments with contrasting characteristics (anoxic or oxic) were resuspended and the release of heavy metals and changes in water chemistry were investigated. During resuspension of the anoxic sediment, the dissolved oxygen (DO) concentration and redox potential of the water layer decreased abruptly within the first 1 min, followed by increases toward the end of the resuspension period. Heavy metals were released rapidly in the first 6 h, probably due to the oxidation of acid volatile sulfide (AVS) of the anoxic sediment, and then the aqueous phase concentrations of the heavy metals decreased due to resorption onto the sediment until the 12-h point. During resuspension of the oxic sediment, the DO concentration and redox potential remained relatively constant in the oxic ranges. The heavy metals were released from the oxic sediment gradually during a 24-h resuspension period. The temporal maximum concentrations of Ni, Cu, Zn, and Cd in the aqueous phases in both experiments frequently exceeded the USEPA water quality criteria or the water quality guidelines of Australia and New Zealand. This suggests that a resuspension event could bring about temporal water quality deterioration in the two sediment environments. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Bioaccumulation of heavy metals in water, sediment and fish ...

African Journals Online (AJOL)

Dr. Hnay

2012-09-25

Sep 25, 2012 ... these pollutants is the chemical substances that stay longer and become toxic in water columns. Within them, heavy metals have positive effects on the vital activities of several organisms and impairment in food chain by affecting biological activities of the living organisms in ecosystem (Gundogu and Erden ...

Heavy quark effective theory and heavy baryon transitions

International Nuclear Information System (INIS)

Hussain, F.

1992-01-01

The heavy quark effective theory (HQET) is applied to study the weak decay of heavy mesons and heavy baryons and to predict the form factors for heavy to heavy and heavy to light transitions. 28 refs, 10 figs, 2 tabs

Possibilities for reorientation of activity in Heavy Water Plants

International Nuclear Information System (INIS)

Pop, F.; Croitoru, C.; Titescu, Gh.; Stefanescu, I.; Hodor, I.; Cuna, S.

2004-01-01

In Romania heavy water is produced by H 2 O-H 2 S chemical exchange (GS process) and by water distillation, in two lines working simultaneously. The distillation plants have high separation capacity, a distillation line being able to concentrate water from two GS lines. The paper presents data regarding possibilities to use one distillation line for oxygen - 18 production, as pre-concentrates or finite products. A simulation program was used to calculate the oxygen - 18 concentration in the heavy water produced, maximum 18 O concentration of pre-concentrate obtained on distillation line and the separation cascade sizes to obtain 95% 18 O, with first and second stage having the same sizes like the distillation plant from the Romanian heavy water factory. Oxygen-18 separation factor is much lower than deuterium separation factor. For this reason, oxygen-18 is a very expensive product. (authors)

Study of the heavy water regeneration processes; Studija procesa za regeneraciju teske vode

Energy Technology Data Exchange (ETDEWEB)

Cavcic, E [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1965-11-15

Experience derived from heavy water reactor operation showed degradation and dilution of heavy water to be inevitable depends on the type of reactor. Dilution of heavy water during operation of the RA and the RB reactors is shown in this report. Principles and procedures of heavy water regeneration by electrolysis, fractional distillation, cleaning, prevention of tritium contamination are described as well as separation columns.

Conceptual designing of reduced-moderation water reactor with heavy water coolant

Energy Technology Data Exchange (ETDEWEB)

Hibi, Kohki; Shimada, Shoichiro; Okubo, Tsutomu E-mail: okubo@hems.jaeri.go.jp; Iwamura, Takamichi; Wada, Shigeyuki

2001-12-01

The conceptual designing of reduced-moderation water reactors, i.e. advanced water-cooled reactors using plutonium mixed-oxide fuel with high conversion ratios more than 1.0 and negative void reactivity coefficients, has been carried out. The core is designed on the concept of a pressurized water reactor with a heavy water coolant and a triangular tight lattice fuel pin arrangement. The seed fuel assembly has an internal blanket region inside the seed fuel region as well as upper and lower blanket regions (i.e. an axial heterogeneous core). The radial blanket fuel assemblies are introduced in a checkerboard pattern among the seed fuel assemblies (i.e. a radial heterogeneous core). The radial blanket region is shorter than the seed fuel region. This study shows that the heavy water moderated core can achieve negative void reactivity coefficients and conversion ratios of 1.06-1.11.

Heavy water production by alkaline water electrolysis

International Nuclear Information System (INIS)

Kamath, Sachin; Sandeep, K.C.; Bhanja, Kalyan; Mohan, Sadhana; Sugilal, G.

2014-01-01

Several heavy water isotope production processes are reported in literature. Water electrolysis in combination with catalytic exchange CECE process is considered as a futuristic process to increase the throughput and reduce the cryogenic distillation load but the application is limited due to the high cost of electricity. Any improvement in the efficiency of electrolyzers would make this process more attractive. The efficiency of alkaline water electrolysis is governed by various phenomena such as activation polarization, ohmic polarization and concentration polarization in the cell. A systematic study on the effect of these factors can lead to methods for improving the efficiency of the electrolyzer. A bipolar and compact type arrangement of the alkaline water electrolyzer leads to increased efficiency and reduced inventory in comparison to uni-polar tank type electrolyzers. The bipolar type arrangement is formed when a number of single cells are stacked together. Although a few experimental studies have been reported in the open literature, CFD simulation of a bipolar compact alkaline water electrolyzer with porous electrodes is not readily available.The principal aim of this study is to simulate the characteristics of a single cell compact electrolyzer unit. The simulation can be used to predict the Voltage-Current Density (V-I) characteristics, which is a measure of the efficiency of the process.The model equations were solved using COMSOL multi-physics software. The simulated V-I characteristic is compared with the experimental data

Conceptual design of a large heavy water reactor for US siting

International Nuclear Information System (INIS)

Shapiro, N.L.; Jesick, J.F.

1979-09-01

Information is presented concerning fuel management and safety and licensing assessment of the pressurized heavy water reactor; and commercial introduction of the pressurized heavy water reactor in the United States

Study on the Effect of Heavy metals toxicity according to changing Hardness concentration using D.magna

Science.gov (United States)

Chun Sang, H.

2016-12-01

n order to determine and prevent the number of ecological effects of heavy metals in the materials, we have to accurately measure the heavy metals present in the water-based protection ecosystems and may determine the effects to humans. Heavy metals occurred in the industrial effluent which is a state in which the monitor, based on the emission standards are made by the Ministry of Environment and managed and waste water contained Copper, Zinc, lead, etc. These heavy metals are able to express the toxic effects only when present in the free-ions in the aqueous condition, which appears differently affected by the degree to hardness change in accordance with the season, precipitation. Generally changing hardness concentration can not precisely evaluate toxic effects of heavy metals in the water system. Anderson announced a study on bioassay for heavy metals from industrial waste water using Daphnia magna(Anderson, 1944, 1948). Breukelman published study the resitivity difference for the mercury Chloride(HgCl2). Braudouin(1974) compared the zooplankton(Daphnia sp.) acute toxicity of the different heavy metals and confirmed the sensitivity. Shcherban(1979) presented for toxicity evaluation results for the heavy metal of the Daphnia magna according to different temperature conditions. In the United States Environmental Protection Agency(EPA) established a standard test method for water fleas, managed and supervised water ecosystems, and announced the adoption of a bioassay standard method. This study was performed to evaluate acute inhibition using the Daphnia magna for the biological effect of heavy metal ions in water-based toxicity in the hardness change. Evaluation methods were conducted in EPA Water Quality process test criteria. TU(Toxic Unit), NOEC (No Observable Effect Concentration), LOEC (Lowest Observable Effect Concentration), EC50 (Median Effective Concentration) was calculated by Toxcalc 5.0 Program. Keywords : D. magna, Hardness, Toxic Unit, Heavy metal

Effect of water-washing on the co-removal of chlorine and heavy metals in air pollution control residue from MSW incineration.

Science.gov (United States)

Yang, Zhenzhou; Tian, Sicong; Ji, Ru; Liu, Lili; Wang, Xidong; Zhang, Zuotai

2017-10-01

The present study systemically investigated the effect of a water-washing process on the removal of harmful chlorides, sulfates, and heavy metals in the air pollution control (APC) residue from municipal solid wastes incineration (MSWI), for sake of a better reuse and disposal of this kind of waste. In addition, the kinetic study was conducted to reveal the releasing mechanism of relevant element in the residue. The results show that, over 70wt.% of chlorides and nearly 25wt.% of sulfates in the residue could be removed by water washing. Based on an economical consideration, the optimal operation conditions for water washing of APC residue was at liquid/solid (L/S) ratio of 3mL:1g and extracting time of 5min. As expected, the concentrations of Co, Cr, Fe, Ni, V and Cu in the washing effluent increased with time during the washing process. However, the extracting regime differs among different heavy metals. The concentrations of Ba and Mn increased firstly but declined afterwards, and concentrations of Pb and Zn gradually declined while Cd and As kept constant with the increase of extracting time. It is worth mentioning that the bubbling of CO 2 into the washing effluent is promisingly effective for a further removal of Pb, Cu and Zn. Furthermore, kinetic study of the water washing process reveals that the extracting of heavy metals during water washing follows a second-order model. Copyright © 2017 Elsevier Ltd. All rights reserved.

76 FR 52994 - Application for a License To Export Heavy Water

Science.gov (United States)

2011-08-24

... NUCLEAR REGULATORY COMMISSION Application for a License To Export Heavy Water Pursuant to 10 CFR... (liters). producing an active water). pharmaceutical ingredient known as CTP-499, which incorporates heavy water as the source of deuterium to achieve the hydrogen-deuterium exchange. November 30, 2010 December...

Assessment of natural radioactivity and heavy metals in water and soil around seismically active area

International Nuclear Information System (INIS)

Oktay Baykara; Mahmut Dogru; Firat University, Elazig

2010-01-01

The natural radioactivity concentration and some heavy metals in various water and soil samples collected from seismically active area have been determined. Gross-alpha and beta concentrations of different 33 water samples and some heavy metal (Fe, Pb, Cu, K, Mn, Cr and Zn) concentration in 72 soil samples collected from two major fault systems (North and East Anatolian Active Fault Systems) in Turkey have been studied. This survey regarding gross-alpha and beta radioactivity and some heavy metals concentrations was carried out by means of Krieger method using a gross-alpha and beta-counting system and atomic absorption spectrometry (AAS), respectively. Also, gross annual effective dose from the average gross-alpha activity in waters were calculated. (author)

[Mapping Critical Loads of Heavy Metals for Soil Based on Different Environmental Effects].

Science.gov (United States)

Shi, Ya-xing; Wu, Shao-hua; Zhou, Sheng-lu; Wang, Chun-hui; Chen, Hao

2015-12-01

China's rapid development of industrialization and urbanization causes the growing problem of heavy metal pollution of soil, threatening environment and human health. Therefore, prevention and management of heavy metal pollution become particularly important. Critical loads of heavy metals are an important management tool that can be utilized to prevent the occurrence of heavy metal pollution. Our study was based on three cases: status balance, water environmental effects and health risks. We used the steady-state mass balance equation to calculate the critical loads of Cd, Cu, Pb, Zn at different effect levels and analyze the values and spatial variation of critical loads. In addition, we used the annual input fluxes of heavy metals of the agro-ecosystem in the Yangtze River delta and China to estimate the proportion of area with exceedance of critical loads. The results demonstrated that the critical load value of Cd was the minimum, and the values of Cu and Zn were lager. There were spatial differences among the critical loads of four elements in the study area, lower critical loads areas mainly occurred in woodland and high value areas distributed in the east and southwest of the study area, while median values and the medium high areas mainly occurred in farmland. Comparing the input fluxes of heavy metals, we found that Pb and Zn in more than 90% of the area exceeded the critical loads under different environmental effects in the study area. The critical load exceedance of Cd mainly occurred under the status balance and the water environmental effect, while Cu under the status balance and water environmental effect with a higher proportion of exceeded areas. Critical loads of heavy metals at different effect levels in this study could serve as a reference from effective control of the emissions of heavy metals and to prevent the occurrence of heavy metal pollution.

Spatiotemporal Analysis of Heavy Metal Water Pollution in Transitional China

Directory of Open Access Journals (Sweden)

Huixuan Li

2015-07-01

Full Text Available China’s socioeconomic transitions have dramatically accelerated its economic growth in last three decades, but also companioned with continuous environmental degradation. This study will advance the knowledge of heavy metal water pollution in China from a spatial–temporal perspective. Specifically, this study addressed the following: (1 spatial patterns of heavy metal water pollution levels were analyzed using data of prefecture-level cities from 2004 to 2011; and (2 spatial statistical methods were used to examine the underlying socioeconomic and physical factors behind water pollution including socioeconomic transitions (industrialization, urbanization, globalization and economic development, and environmental characteristic (natural resources, hydrology and vegetation coverage. The results show that only Cr pollution levels increased over the years. The individual pollution levels of the other four heavy metals, As, Cd, Hg, and Pb, declined. High heavy metal water pollution levels are closely associated with both anthropogenic activities and physical environments, in particular abundant mineral resources and industrialization prosperity. On the other hand, economic development and urbanization play important roles in controlling water pollution problems. The analytical findings will provide valuable information for policy-makers to initiate and adjust protocols and strategies for protecting water sources and controlling water pollution; thus improving the quality of living environments.

Radionuclides and heavy metal uptake by lolium italicum plant as affected by saline water irrigation

International Nuclear Information System (INIS)

Ramadan, A.A.; Aly, A.I.; Helal, M.H.

2001-01-01

The use of saline waters to grow crops on increasingly metal polluted soils is becoming a common practice in the arid regions. Nevertheless, the effects of soil and water salinity on radionuclides and heavy metal fluxes in polluted areas are not well understood. The aim of this study was to evaluate in pot experiments the plant uptake of cesium-137, Co-60, Mn-54, Zinc, cadmium and copper from a polluted alluvial aridisol as affected by salt water irrigation. Fertilized soil material was planted in pots with L. Italicum for 18 weeks under greenhouse conditions. The plants were irrigated either with water or with salt solution of variable variable Na/Ca ratio and harvested every 5-7 weeks. In addition to elemental analysis of plants and soil extracts root length was determined by a gridline intersect method and the viable part of the roots was estimated by a root protein inex. Saline (Na) water irrigation increased cobalt-60, manganese-54 and heavy metal solubility in soil, reduced root viability and enhanced the uptake of Co-60, Mn-54, Cd, Cu, Zn and Na by L.italicum and reduced the uptake of Cs-137. Ca counteracted these effects partly. The presented results demonstrated a dual effect of salinity on radiouclides and heavy metal availability to plants and suggest a relationship between root mortality and the enhanced Co-60, Mn-54, and heavy metake ny salt stressed plants

Extending the product variety at ROMAG-PROD Heavy Water Plant

International Nuclear Information System (INIS)

Preda, M.; Patrascu, M.; Achimescu, D.; Stroia, A.

2004-01-01

Full text: Having in mind that the prospects of operating the ROMAG-PROD Heavy Water Plant are conditioned by both the heavy water market demand and the wear of the equipment which is exposed to hydrogen sulfide-induced corrosion, some possibilities were considered to extend the assortment of products, the production of which could ensure the plant's operation on long term. The proposals here refer to promoting the efficient production of oxygen-isotope-based products which would optimize maximally the exploit of available raw materials, supply and utilities of the ROMAG compound. The market manifests a significant demand of water enriched in the 18 O isotope up to 95-97% purity that is used in Positron Emission Tomography (PET). This oxygen isotope is also used as a labelling agent in studies of reaction mechanisms and paleo-climatologic studies as well. Some research evidenced the superconducting properties of some oxygen compounds containing the 18 O isotope. The isotope 17 O has applications in Nuclear Magnetic Resonance (NMR) as being the sole oxygen isotope endowed with a nuclear magnetic moment. On the other hand, it was found that although the 16 O isotope has a natural abundance of 99.8%, applications exist that require the absolute purity of this isotope i.e. the elimination of the other oxygen isotopes as is the case of fission reactors with Plutonium dioxide as nuclear fuel. The methods applied on industrial scale for enriching the oxygen isotopes are based on distillation of some oxygen compounds such as water and nitrogen monoxide. The possibility of a supplementary distillation of the heavy water at a distillation line of ROMAG-PROD Heavy Water Plant was considered in order to enrich the heavy water in the 17 O and 18 O isotopes up to an upper limit of 2-5% for 18 O. Obtaining the heavy isotopes of oxygen by distillation of heavy water is characterized by several aspects as the following ones: a high specific consumption of steam due to both the low

Simulation of heavy metal contamination of fresh water bodies: toxic ...

African Journals Online (AJOL)

Michael Horsfall

www.bioline.org.br/ja. Simulation of heavy metal contamination of fresh water bodies: toxic effects in the ... 96 hours (though sampling was done at the 48th hour). Biochemical markers of ... silver, while enhancing the bioavailability of mercury in Ceriodaphnia ..... Biochemical and molecular disorders of bilirubin metabolism.

Cooling water treatment for heavy water project (Paper No. 6.9)

International Nuclear Information System (INIS)

Valsangkar, H.N.

1992-01-01

With minor exceptions, water is the preferred industrial medium for the removal of unwanted heat from process systems. The application of various chemical treatments is required to protect the system from water related and process related problems of corrosion, scale and deposition and biofouling. The paper discusses the cooling water problems for heavy water industries along with the impact caused by associated fertilizer units. (author). 6 figs

Effectiveness Study of Drinking Water Treatment Using Clays/Andisol Adsorbent in Lariat Heavy Metal Cadmium (Cd) and Bacterial Pathogens

Science.gov (United States)

Pranoto; Inayati; Firmansyah, Fathoni

2018-04-01

Water is a natural resource that is essential for all living creatures. In addition, water also caused of disease affecting humans. The existence of one of heavy metal pollutants cadmium (Cd) in the body of water is an environmental problem having a negative impact on the quality of water resources. Adsorption is one of the ways or methods that are often used for the treatment of wastewater. Clay and allophanic soil were used as Cd adsorbent by batch method. Ceramic filter was used to reduce Cd concentration in the ground water. This study aims to determine the effect of the composition of clay and Allophane, activation temperature and contact time on the adsorption capacity of Cd in the model solution. The optimum adsorption condition and the effectiveness of drinking water treatment in accordance with Regulation of the Minister of Health using clay/Andisol adsorbents in ensnare heavy metals Cd and bacterial pathogens. Identification and characterization of adsorbent is done by using NaF, Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), specific surface area and total acidity specific. The Cd metal concentrations were analysed by atomic absorption spectroscopy. Adsorption isotherms determined by Freundlich and Langmuir equations. Modified water purification technology using ceramic filters are made with a mixture of clay and Andisol composition. The results showed samples of clay and Andisol containing minerals. The optimum condition of adsorption was achieved at 200 °C of activation temperature, 60 minutes of contact time and the 60:40 of clay:Andisol adsorbent composition. Freundlich isotherm represented Cd adsorption on the clay/Andisol adsorbent with a coefficient of determination (R2=0.99) and constant (k=1.59), higher than Langmuir (R2=0.89). The measurement results show the water purification technology using ceramic filters effectively reduce E. coli bacterial and Cd content in the water.

Heavy water technology and its contribution to energy sustainability

International Nuclear Information System (INIS)

MacDiarmid, H.; Alizadeh, A.; Hopwood, J.; Duffey, R.

2009-01-01

Full text: As the global nuclear industry expands several markets are exploring avenues and technologies to underpin energy security. Heavy water reactors are the most versatile power reactors in the world. They have the potential to extend resource utilization significantly, to allow countries with developing industrial infrastructures access to clean and abundant energy, and to destroy long-lived nuclear waste. These benefits are available by choosing from an array of possible fuel cycles. Several factors, including Canada's early focus on heavy-water technology, limited heavy-industry infrastructure at the time, and a desire for both technological autonomy and energy self-sufficiency, contributed to the creation of the first commercial heavy water reactor in 1962. With the maturation of the industry, the unique design features of the now-familiar product-on-power refuelling, high neutron economy, and simple fuel design-make possible the realization of its potential fuel-cycle versatility. As resource constrains apply pressure on world markets, the feasibility of these options have become more attractive and closer to entering widespread commercial application

HEAVY METALS AS UNWANTED COMPONENTS OF BACKWASH WATER DERIVED FROM GROUNDWATER TREATMENT

Directory of Open Access Journals (Sweden)

Robert Nowak

2016-06-01

Full Text Available The paper presents some aspects of the problem of heavy metals presence in wastewater and sewage sludge from water treatment. In the first part, issues on quality of wastewaters and sludge produced during water treatment along with actions aimed at the neutralization of such wastes, were discussed. Subsequent parts of the work present the example of 12 groundwater treatment stations in a particular municipality, and the problem of backwash water quality, in particular, heavy metals contents. The analysis covered a period of three years: 2013, 2014, and 2015. The authors, using the discussed examples, have shown that besides hydrated iron and manganese oxides, also other toxic contaminants can be present in backwash water from groundwater treatment. In particular, the qualitative analysis of the backwash water revealed the presence of heavy metals, mainly zinc. The test results for backwash water were compared with those of filtrate qualitative assessment, wherein the heavy metals were not found. This fact indicated the metal retention in the filter bed and their unsustainable immobilization resulting in penetration of heavy metals from deposit to the backwash water along with other impurities, mainly iron and manganese oxides. The main conclusion from the study is to demonstrate the need for constant monitoring of the backwash water quality, including the presence of toxic heavy metals. This is also important because of the requirement to minimize the negative environmental impact of wastes generated during the water treatment process.

Irrigation water quality influences heavy metal uptake by willows in biosolids.

Science.gov (United States)

Laidlaw, W Scott; Baker, Alan J M; Gregory, David; Arndt, Stefan K

2015-05-15

Phytoextraction is an effective method to remediate heavy metal contaminated landscapes but is often applied for single metal contaminants. Plants used for phytoextraction may not always be able to grow in drier environments without irrigation. This study investigated if willows (Salix x reichardtii A. Kerner) can be used for phytoextraction of multiple metals in biosolids, an end-product of the wastewater treatment process, and if irrigation with reclaimed and freshwater influences the extraction process. A plantation of willows was established directly onto a tilled stockpile of metal-contaminated biosolids and irrigated with slightly saline reclaimed water (EC ∼2 dS/cm) at a wastewater processing plant in Victoria, Australia. Biomass was harvested annually and analysed for heavy metal content. Phytoextraction of cadmium, copper, nickel and zinc was benchmarked against freshwater irrigated willows. The minimum irrigation rate of 700 mm per growing season was sufficient for willows to grow and extract metals. Increasing irrigation rates produced no differences in total biomass and also no differences in the extraction of heavy metals. The reclaimed water reduced both the salinity and the acidity of the biosolids significantly within the first 12 months after irrigation commenced and after three seasons the salinity of the biosolids had dropped to metal extraction. Reclaimed water irrigation reduced the biosolid pH and this was associated with reductions of the extraction of Ni and Zn, it did not influence the extraction of Cu and enhanced the phytoextraction of Cd, which was probably related to the high chloride content of the reclaimed water. Our results demonstrate that flood-irrigation with reclaimed water was a successful treatment to grow willows in a dry climate. However, the reclaimed water can also change biosolids properties, which will influence the effectiveness of willows to extract different metals. Copyright © 2015 Elsevier Ltd. All rights

"Periodic-table-style" paper device for monitoring heavy metals in water.

Science.gov (United States)

Li, Miaosi; Cao, Rong; Nilghaz, Azadeh; Guan, Liyun; Zhang, Xiwang; Shen, Wei

2015-03-03

If a paper-based analytical device (μ-PAD) could be made by printing indicators for detection of heavy metals in chemical symbols of the metals in a style of the periodic table of elements, it could be possible for such μ-PAD to report the presence and the safety level of heavy metal ions in water simultaneously and by text message. This device would be able to provide easy solutions to field-based monitoring of heavy metals in industrial wastewater discharges and in irrigating and drinking water. Text-reporting could promptly inform even nonprofessional users of the water quality. This work presents a proof of concept study of this idea. Cu(II), Ni(II), and Cr(VI) were chosen to demonstrate the feasibility, specificity, and reliability of paper-based text-reporting devices for monitoring heavy metals in water.

Canned motor pumps at Heavy Water Project, Baroda

International Nuclear Information System (INIS)

Batra, R.K.; Waishampayan, S.C.

1981-01-01

Pumps to be used in heavy water plants must be reliable and should require negligible maintenance, because most of them are totally unapproachable under normal circumstances. Canned motor pumps fulfil these requirements. Their design features are described briefly. The details of: (1) the pumps in the isotopic exchange tower and (2) pumps for liquid ammonia and catalyst are given. Problems faced during commissioning of such pumps in Baroda Heavy Water Project were bulging of rotors of tower pumps, bulging of stators, jamming and failure of bearings. Solution of these problems is described. (M.G.B.)

Thermal neutron standard fields with the KUR heavy water facility

International Nuclear Information System (INIS)

Kanda, K.; Kobayashi, K.; Shibata, T.

1978-01-01

A heavy water facility attached to the KUR (Kyoto University Reactor, swimming pool type, 5 MW) yields pure thermal neutrons in the Maxwellian distribution. The facility is faced to the core of KUR and it contains about 2 tons of heavy water. The thickness of the layer is about 140 cm. The neutron spectrum was measured with the time of flight technique using a fast chopper. The measured spectrum was in good agreement with the Maxwellian distribution in all energy region for thermal neutrons. The neutron temperature was slightly higher than the heavy water temperature. The contamination of epithermal and fast neutrons caused by photo-neutrons of the γ-n reaction of heavy water was very small. The maximum intensity of thermal neutrons is 3x10 11 n/cm 2 sec. When the bismuth scatterer is attached, the gamma rays contamination is eliminated by the ratio of 0.05 of gamma rays to neutrons in rem. This standard neutron field has been used for such experiments as thermal neutron cross section measurement, detector calibration, activation analysis, biomedical purposes etc. (author)

Study of minor actinides transmutation in heavy water cooled tight-pitch lattice

International Nuclear Information System (INIS)

Xu Xiaoqin; Shiroya, S.

2002-01-01

Minor actinides inhere long half-life and high toxicity. It is an alternative technical pathway and helpful for reducing environmental impact to incinerate minor actinides in spent fuel of nuclear power plants. Because of its high neutron, γ and β emitting rates and heat generation rate, it is necessary to imply more severe control and shielding techniques in the chemical treatment and fabrication. From economic view-point, it is suitable to transmute minor actinides in concentrated way. A technique for MA transmutation by heavy water cooled tight-pitch lattice system is proposed, and calculated with SRAC95 code system. It is shown that tight-pitch heavy water lattice can transmute MA effectively. The accelerator-driven subcritical system is practical for MA transmutation because of its low fraction of effective delay neutrons

1000 tones of heavy water produced at ROMAG PROD, Drobeta-Turnu Severin

International Nuclear Information System (INIS)

2001-01-01

On May 25, 2001 the heavy water plant ROMAG PROD at Drobeta-Turnu Severin recorded the production of the 1000-th tone of nuclear purity heavy water. The heavy water plant ROMAG PROD makes use of a technology based on the results of isotopic deuterium separation research carried out at the Research and Design Institutes of Cluj, Craiova, Pitesti and Ploiesti during 1957-1970 and the separation technology tested at Ramnicu-Valcea pilot plant (at present the Cryogenics and Isotope Separation Institute). The first investments at ROMAG PROD were made in 1979 and on July 17, 1988 was produced the first amount of heavy water at the required parameters for CANDU type nuclear reactors. The period between 1990-1992 was dedicated to the project completion, upgrading the technological facilities and retrofitting the environmental protection and monitoring systems. Production was resumed in 1992. The first 500 t of heavy water required for the Cernavoda NPP first reactor operation were produced by summer 1997. The additional amount of 500 t of heavy water was produced between 1997-2001. ROMAG PROD obtained the ISO 9001/2001 certificate for the quality management system, the ISO 14001/1997 certificate for the environmental management system and the new environmental permit

Transformation of heavy metals in lignite during supercritical water gasification

International Nuclear Information System (INIS)

Chen, Guifang; Yang, Xinfei; Chen, Shouyan; Dong, Yong; Cui, Lin; Zhang, Yong; Wang, Peng; Zhao, Xiqiang; Ma, Chunyuan

2017-01-01

Highlights: • The transformations of heavy metals during lignite SCWG were investigated. • The risks of heavy metals in lignite and residues after SCWG were evaluated. • The effects of experimental conditions on corrosion during SCWG were studied. - Abstract: Transformation characteristics of heavy metals during lignite supercritical water gasification (SCWG) were studied. A sequential extraction procedure (modified Tessier method) was used to selectively extract different fractions of Pb, Cd, Cr, Mn, Cu, Ni, and Zn. Heavy metals transformed into more stable fractions after SCWG. For Pb, Cd, Mn, Cu, and Zn, SCWG reduced the bioavailability and the risks posed by heavy metals in lignite. Under the experimental conditions, the conversion rates for Pb and Cd were 16.0%–25.2% and 16.3%–23.4%, respectively, whereas those for Mn, Cu, and Zn were much lower. Solid products enriched with Pb, Cd, Mn, Cu, and Zn were obtained after SCWG; the contents of these metals varied slightly in the liquid products under different experimental conditions. Excess Cr and Ni that did not originate from lignite were found in the residues, owing to reactor corrosion during lignite SCWG. Higher temperatures alleviated corrosion, whereas higher pressures and equivalence ratios (ER) had the opposite effect. None of the heavy metals were detected in the gas phase under the experimental conditions used in the present study. The correlation between the distributions of heavy metals and the experimental conditions were also studied. The transformation pathways of Pb, Cd, Mn, Cu, and Zn during SCWG were deduced according to the experimental results.

Heat exchangers in heavy water reactor systems

International Nuclear Information System (INIS)

Mehta, S.K.

1988-01-01

Important features of some major heat exchange components of pressurized heavy water reactors and DHRUVA research reactor are presented. Design considerations and nuclear service classifications are discussed

Environmental assessment of ground water pollution by heavy ...

African Journals Online (AJOL)

The aim of this study was to investigate the relationship between the concentrations of heavy metals in well water and bioaccumulation of the most abundant metals in chicken tissues in some areas in the province of Mecca Almokaramah, Saudi Arabia. Among the heavy metals (Cd, Zn, Cr, Mn, Cu Hg, Pb and Ni) studied, ...

Effects of phytoextraction on heavy metal concentrations and pH of pore-water of biosolids determined using an in situ sampling technique.

Science.gov (United States)

Huynh, T T; Laidlaw, W S; Singh, B; Gregory, D; Baker, A J M

2008-12-01

Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salixxreichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S.xreichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process.

Solution enthalpies of alkali metal halides in water and heavy water mixtures with dimethyl sulfoxide

International Nuclear Information System (INIS)

Egorov, G.I.

1994-01-01

Solution enthalpies of CsF, LiCl, NaI, CsI and some other halides of alkali metals and tetrabutylammonium have been measured by the method of calorimetry. Standard solution enthalpies of all alkali metals (except rubidium) halides in water and heavy water mixtures with dimethylsulfoxide at 298.15 K have been calculated. Isotopic effects in solvation enthalpy of the electrolytes mentioned in aqueous solutions of dimethylsulfoxide have been discussed. 29 refs., 2 figs., 4 tabs

Evaluation of heavy metals level (arsenic, nickel, mercury and lead effecting on health in drinking water resource of Kohgiluyeh county using geographic information system (GIS

Directory of Open Access Journals (Sweden)

Abdolazim Alinejad

2016-08-01

Full Text Available This study was conducted to determine the amount of heavy metals (Arsenic, Nickel, Mercury, and Lead in drinking water resource of Kohgiluyeh County using Geographic Information System (GIS. This cross-sectional study was conducted on drinking water resource of Kohgiluyeh County (33 water supplies and 4 heavy metals in 2013. 264 samples were analyzed in this study. The experiments were performed at the laboratory of Water and Wastewater Company based on Standard Method. The Atomic Adsorption was used to evaluate the amount of heavy metals. The results were mapping by Geographic Information System software (GIS 9.3 after processing of parameters. Finally, the data were analyzed by SPSS 16 and Excel 2007. The maximum amount of each heavy metal and its resource were shown as follow: Nickel or Ni (Source of w12, 124ppb, Arsenic or As (w33, 42 ppb, Mercury or Hg (w22 and w30, 96ppb, Lead or Pb (w21, 1553ppb. Also, the GIS maps showed that Lead in the central region was very high, Mercury and Arsenic in the northern region were high and Nickel in the eastern and western regions was high. The Kriging method and Gauss model were introduced as best method for interpolation of these metals. Since the concentration of these heavy metals was higher than standard levels in most drinking water supplies in Kohgiluyeh County and these high levels of heavy metals can cause the adverse effects on human health; therefore, the environmental and geological studies are necessary to identify the pollution resource and elimination and removal of heavy metals

Operating experiences on ammonia water exchange system at Heavy Water Plant, Talcher (paper No. 6.12)

International Nuclear Information System (INIS)

Venkat Ram, D.; Sharma, A.K.

1992-01-01

The Heavy Water Plant at Talcher employs bithermal ammonia hydrogen exchange process for the production of heavy water. The paper describes about the existing ammonia water exchange column, its start-up, operating experience and the problems encountered in operation of the column. The operating experiences gained and the data collected over the last few years can be utilised for design and operation of new ammonia water exchange column. (V.R). 2 figs

Some environmental effects of emissions from CANDU nuclear generating stations and heavy water plants

International Nuclear Information System (INIS)

Effer, W.R.

Non-radioactive releases during normal operation of Ontario Hydro's nuclear generating stations and heavy water plants are summarized and related to existing regulations and guidelines. Low-grade heat in the circulating cooling water discharge is the most important of the non-radioactive effluents. Some of the hydrological, biological and water quality aspects of thermal discharges are discussed in relation to the operation of Ontario Hydro's thermal generating stations on the Great Lakes. Chemical releases to air or water include chlorine, hydrogen sulphide, water treatment plant effluents, oily waste water and sewage lagoon effluents. The significance of the first two of these releases to the environment is reviewed, particularly in relation to Great Lakes water quality and biological concerns. (author)

Heavy metal partitioning of suspended particulate matter-water and sediment-water in the Yangtze Estuary.

Science.gov (United States)

Feng, Chenghong; Guo, Xiaoyu; Yin, Su; Tian, Chenhao; Li, Yangyang; Shen, Zhenyao

2017-10-01

The partitioning of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) between the water, suspended particulate matter (SPM), and sediments in seven channel sections during three hydrologic seasons in the Yangtze Estuary was comprehensively investigated. Special attention was paid to the role of tides, influential factors (concentrations of SPM and dissolved organic carbon, and particle size), and heavy metal speciation. The SPM-water and sediment-water partition coefficients (K p ) of the heavy metals exhibited similar changes along the channel sections, though the former were larger throughout the estuary. Because of the higher salinity, the K p values of most of the metals were higher in the north branch than in the south branch. The K p values of Cd, Co, and As generally decreased from the wet season to the dry season. Both the diagonal line method and paired samples t-test showed that no specific phase transfer of heavy metals existed during the flood and ebb tides, but the sediment-water K p was more concentrated for the diagonal line method, owing to the relatively smaller tidal influences on the sediment. The partition coefficients (especially the K p for SPM-water) had negative correlations with the dissolved organic carbon (DOC) but positive correlations were noted with the particle size for most of the heavy metals in sediment. Two types of significant correlations were observed between K p and metal speciation (i.e., exchangeable, carbonate, reducible, organic, and residual fractions), which can be used to identify the dominant phase-partition mechanisms (e.g., adsorption or desorption) of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Change of deuterium volume content in heavy water during carbon dioxide dissolution in it

International Nuclear Information System (INIS)

Efimova, T.I.; Kapitanov, V.F.; Levchenko, G.V.

1985-01-01

Carbon dioxide solution density in heavy water at increased temperature and pressure is measured and the influence of carbon dioxide solubility in heavy water on volumetric content of deuterium in it is determined. Investigations were conducted in the temperature range of 303-473 K and pressure range of 3-20 MPa by the autoclave method. Volumetric content of deuterium in heavy water decreases sufficiently with CO 2 dissolved in it in comparison with pure D 2 O under the similar conditions, and this decrease becomes more sufficient with the pressure increase. With the temperature increase the volumetric content of deuterium both for heavy water and for saturated carbon solution in heavy water decreases

The future 700 MWe pressurized heavy water reactor

International Nuclear Information System (INIS)

Bhardwaj, S.A.

2006-01-01

The design of a 700 MWe pressurized heavy water reactor has been developed. The design is based on the twin 540 MWe reactors at Tarapur of which the first unit has been made critical in less than 5 years from construction commencement. In the 700 MWe design boiling of the coolant, to a limited extent, has been allowed near the channel exit. While making the plant layout more compact, emphasis has been on constructability. Saving in capital cost of about 15%, over the present units, is expected. The paper describes salient design features of 700 MWe pressurized heavy water reactor

Heavy baryon transitions and the heavy quark effective theory

International Nuclear Information System (INIS)

Hussain, F.

1992-01-01

Heavy baryon decays are studied in the context of the Bethe-Salpeter approach to the heavy quark effective theory. A drastic reduction, in the number of independent form factors, is found. Results are presented both for heavy to heavy and heavy to light baryon decays. (orig.)

Technologies for tritium control in fission reactors moderated with heavy water

International Nuclear Information System (INIS)

Ramilo, L.B.; Gomez de Soler, S.M.

1996-01-01

This study was done within a program one of whose objectives was to analyze the possible strategies and technologies, to be applied to HWR at Argentine nuclear power plants, for tritium control. The high contribution of tritium to the total dose has given rise to the need by the operators and/or designers to carry out developments and improvements to try to optimize tritium control technologies. Within a tritium control program, only that one which includes the heavy water detritiation will allow to reduce the tritium concentrations at optimum levels for safety and cost-effective power plant operation. The technology chosen to be applied should depend not only on the technical feasibility but also on the analysis of economic and juncture factors such as, among others, the quantity of heavy water to be treated. It is the authors' belief that AECL tendency concerning heavy water treatment in its future reactors would be to employ the CECE technology complemented with immobilization on titanium beds, with the 'on-line' detritiation in each nuclear power plant. This would not be of immediate application since our analysis suggests that AECL would assume that the process is under development and needs to be tested. (author). 21 refs

Development of a purification system at Dhruva to treat oil contaminated and chemically impure heavy water

International Nuclear Information System (INIS)

Suttraway, S.K.; Mishra, V.; Bitla, S.V.; Ghosh, S.K.

2006-01-01

Dhruva, a 100 MW (thermal) Research reactor uses Heavy Water as moderator, reflector and coolant. Normally during plant operation, the Heavy water from the system gets removed during operational and maintenance activities and this collected heavy water gets degraded and contaminated in the process. The degraded heavy water meeting the chemical specification requirement of the up gradation plant is sent for up gradation. Part of the Heavy water collected is contaminated with various organic and inorganic impurities and therefore cannot be sent for IP up gradation as it does not meet the chemical specification of the up gradation plant. This contaminated Heavy water was being stored in SS drums. Over the years of Reactor operation reasonable amount of contaminated Heavy water got collected in the plant. This Heavy water collected from leakages, during routine maintenance, operational activities and fuelling operation had tritium activity and variety of contamination including oil, chlorides, turbidity due to which the specific conductivity was very high. It was decided to purify this Heavy water in house to bring it up to up gradation plant chemical specification requirement. There were number of challenges in formulating a scheme to purify this Heavy water. The scheme needed to be simple and compact in design which could be set up in the plant itself. It should not pose radiological hazards due to radioactive Heavy water during its purification and handling. The contaminated Heavy water collected in drums had varying chemistry and IP. The purification plant should be able to do batch processing so that the different IP and chemical quality of Heavy water stored in different drums are not mixed during purification. It should be capable of removing the oil, chlorides, turbidity and decrease the conductivity to acceptable limits of the Up gradation plant. A purification plant was developed and commissioned after detail laboratory studies and trials. This paper explains

Neutrinos: Heavy water detector

International Nuclear Information System (INIS)

Anon.

1990-01-01

The proponents of the Sudbury Neutrino Observatory (SNO) received a welcome Christmas present when William Winegard, Canadian Minister for Science and Technology announced the final details of the funding for this project, totalling 48 million Canadian dollars and including contributions from the US and the UK. The SNO experiment will extend significantly the study of solar neutrinos, using some 1,000 tonnes of heavy water to be installed more than two kilometres below ground in a nickel mine at Sudbury, Ontario

Effects of moderation level on core reactivity and. neutron fluxes in natural uranium fueled and heavy water moderated reactors

International Nuclear Information System (INIS)

Khan, M.J.; Aslam; Ahmad, N.; Ahmed, R.; Ahmad, S.I.

2005-01-01

The neutron moderation level in a nuclear reactor has a strong influence on core multiplication, reactivity control, fuel burnup, neutron fluxes etc. In the study presented in this article, the effects of neutron moderation level on core reactivity and neutron fluxes in a typical heavy water moderated nuclear research reactor is explored and the results are discussed. (author)

A study of pollution extent in some drinking water resources by heavy elements in Hadramout governorate

International Nuclear Information System (INIS)

Barheyan, Saad Awadh

2001-01-01

The paper is considered as a preliminary study of pollution extent in some drinking water resources in Hadramout governorate by heavy elements which differ in their toxicity. The elements subjected to study are Cd, Pb, Fe, Cr, Mn, Zn, Co and Cu. Atomic absorption spectrometric method of analysis (AAS) is used for the determination of heavy elements concentrations. The elemental analysis of drinking water samples shows that the concentration of the above-mentioned elements in drinking water resources, lies in the permissible limit given by the WHO. Similarity of elements content is observed in Thela and Fuwah waters, bu the case is different for Ghail Bawzeer and Asshihir waters due to their different lithospheric structures. Drinking water used by the civilians is not subjected to physical, biological or chemical treatment which may lead to total or partial removal of heavy elements and other rejected impurities. Drinking water running in distribution nets is a hard water and has a weak base (Ph which explains the reason why heavy elements are absorbed and precipitated inside drinking water pipes before they reach consumers. This type of hard water causes accumulation of salt precipitates inside the water pipes which results in many economic and health disturbances to consumers. The slight increase of Cr, Mn, and Co concentration in drinking water flowing in the pipes may be due to the effect of some anions such as nitrates which form soluble compounds with the elements contained in the chemical composition of the drinking water pipes. This paper is a strong indicator for determination of heavy elements concentrations in different drinking water resources in Hadramout govemorate. Such approach seeks a further comprehensive work with special focus on the study of lithospheric structure of the feeding water regions of Hadramout aquifers. (author)

Stabilization of heavy oil-water emulsions using a bio/chemical emulsifier mixture

Energy Technology Data Exchange (ETDEWEB)

Farahbakhsh, A.; Taghizadeh, M.; Movagharnejad, K. [Chemical Engineering Department, Babol University of Technology, Babol (Iran, Islamic Republic of); Yakhchali, B. [National Institute of Genetic Engineering and Biotechnology, Tehran (Iran, Islamic Republic of)

2011-11-15

In this study, the viscosity reduction of heavy oil has been investigated through the formation of oil-water emulsion using a bio/chemical emulsifier mixture. Four bioemulsifiers from indigenous Rhodococcus ergthropolis and Bacillus licheniformis strains were used to stabilize a highly-viscous oil-in-water emulsion. The Taguchi method with an L{sub 9} orthogonal array design was used to investigate the effect of various control factors on the formation of the oil/water emulsions. An emulsion with lowest viscosity was formed using ACO4 strain. The substantial stability of the oil-in-water emulsion allows the heavy oil to be transported practically over long distances or remain stationary for a considerable period of time prior to utilization. As the result of Taguchi analysis, the temperature and concentration of the emulsifier had a significant influence on viscosity reduction of the emulsion. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Investigation of the heavy water distillation system at the RA reactor

International Nuclear Information System (INIS)

Zecevic, V.; Badrljica, R.

1963-01-01

The heavy water distillation system was tested because this was not done before the reactor start-up. Detailed inspection of the system components showed satisfactory results. Leak testing was done as well as the testing of the instrumentation which enables reliable performance of the system. Performance testing was done with ordinary water and later 2700 l of heavy water from the reactor was purified, decreasing the activity by 45%

Heavy metal contamination of soil and water in the vicinity of an abandoned e-waste recycling site: implications for dissemination of heavy metals.

Science.gov (United States)

Wu, Qihang; Leung, Jonathan Y S; Geng, Xinhua; Chen, Shejun; Huang, Xuexia; Li, Haiyan; Huang, Zhuying; Zhu, Libin; Chen, Jiahao; Lu, Yayin

2015-02-15

Illegal e-waste recycling activity has caused heavy metal pollution in many developing countries, including China. In recent years, the Chinese government has strengthened enforcement to impede such activity; however, the heavy metals remaining in the abandoned e-waste recycling site can still pose ecological risk. The present study aimed to investigate the concentrations of heavy metals in soil and water in the vicinity of an abandoned e-waste recycling site in Longtang, South China. Results showed that the surface soil of the former burning and acid-leaching sites was still heavily contaminated with Cd (>0.39 mg kg(-1)) and Cu (>1981 mg kg(-1)), which exceeded their respective guideline levels. The concentration of heavy metals generally decreased with depth in both burning site and paddy field, which is related to the elevated pH and reduced TOM along the depth gradient. The pond water was seriously acidified and contaminated with heavy metals, while the well water was slightly contaminated since heavy metals were mostly retained in the surface soil. The use of pond water for irrigation resulted in considerable heavy metal contamination in the paddy soil. Compared with previous studies, the reduced heavy metal concentrations in the surface soil imply that heavy metals were transported to the other areas, such as pond. Therefore, immediate remediation of the contaminated soil and water is necessary to prevent dissemination of heavy metals and potential ecological disaster. Copyright © 2014 Elsevier B.V. All rights reserved.

Effective integration between heavy water plant and fertilizer plant for higher production of heavy water (D2O) (Preprint No. PD-10)

International Nuclear Information System (INIS)

Periakaruppan, M.; Gupta, S.K.; Bhowmick, S.C.

1989-04-01

For smooth and efficient running of heavy water plants linked with fertilize r plants, it is necessary that certain factors must be taken into consideration right from the design stage of a fertilizer plant. These factors are: (1)preventing loss in D 2 concentration in syn gas, (2)keeping the level of CO 2 and CO in syn gas below 1 ppm, (3)operating the ammonia plant at highest pressure and (4)keeping the feed gas ammonia supply available without any interruption. Incorporation of these factors in the design is discussed. (M.G.B. )

Operating performance of the prototype heavy water reactor Fugen

International Nuclear Information System (INIS)

1984-01-01

Since the full scale operation was started in March, 1979, the ATR Fugen power station has been verifying the performance and reliability of the machinery and equipment, uranium-plutonium mixed oxide fuel and so on, and obtaining the technical prospect for putting ATRs in practical use by accumulating operation and maintenance techniques, through about five years of operation. In this report, the operational results of the Fugen power station are described. Fugen is a heavy water-moderated, boiling light water-cooled, pressure tube type reactor with 165 MWe output. As of the end of March, 1984, the total generated electric power was about 4.3 billion kWh, and the operation time was about 27,000 hours. The mean capacity ratio reached 58.8%. During the operation period, troubles including plant shutdown occurred eight times, but generally the performance and reliability of the machinery and equipment have been good. 580 fuels including 284 MOX fuels have been charged, but fuel breaking did not occur at all. The consumption of heavy water and the leak of tritium did not cause problem. The management of the core and fuel, the management of maintenance, the quality control of cooling water and heavy water, radiation control and the management of wastes are reported. (Kako, I.)

Light and heavy water replacing system in reactor container

International Nuclear Information System (INIS)

Miyamoto, Keiji.

1979-01-01

Purpose: To enable to determine the strength of a reactor container while neglecting the outer atmospheric pressure upon evacuation, by evacuating the gap between the reactor container and a biological thermal shield, as well as the container simultaneously upon light water - heavy water replacement. Method: Upon replacing light water with heavy water by vacuum evaporation system in a nuclear reactor having a biological thermal shield surrounding the reactor container incorporating therein a reactor core by way of a heat expansion absorbing gap, the reactor container and the havy water recycling system, as well as the inside of heat expansion absorbing gap are evacuated simultaneously. This enables to neglect the outer atmospheric outer pressure upon evacuation in the determination of the container strength, and the thickness of the container can be decreased by so much as the external pressure neglected. (Moriyama, K.)

Effects of phytoextraction on heavy metal concentrations and pH of pore-water of biosolids determined using an in situ sampling technique

Energy Technology Data Exchange (ETDEWEB)

Huynh, T.T. [Applied Ecology Research Group, School of Botany, University of Melbourne, Parkville, VIC 3010 (Australia)], E-mail: t.huynh11@pgrad.unimelb.edu.au; Laidlaw, W.S. [Applied Ecology Research Group, School of Botany, University of Melbourne, Parkville, VIC 3010 (Australia); Singh, B. [Faculty of Agriculture, Food and Natural Resources, University of Sydney, Sydney, NSW 2006 (Australia); Gregory, D. [Research and Technology Division, Melbourne Water, Melbourne, VIC 3001 (Australia); Baker, A.J.M. [Applied Ecology Research Group, School of Botany, University of Melbourne, Parkville, VIC 3010 (Australia)

2008-12-15

Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salix x reichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S. x reichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process. - Salix x reichardtii and Populus balsamifera extracted Ni, Zn and Cd and mobilized these metals in biosolids during phytoextraction.

Effects of phytoextraction on heavy metal concentrations and pH of pore-water of biosolids determined using an in situ sampling technique

International Nuclear Information System (INIS)

Huynh, T.T.; Laidlaw, W.S.; Singh, B.; Gregory, D.; Baker, A.J.M.

2008-01-01

Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salix x reichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S. x reichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process. - Salix x reichardtii and Populus balsamifera extracted Ni, Zn and Cd and mobilized these metals in biosolids during phytoextraction

The Bare Critical Assembly of Natural Uranium and Heavy Water

Energy Technology Data Exchange (ETDEWEB)

Popovic, D [Boris Kidric Institute of Nuclear Sciences, Vinca, Belgrade (Yugoslavia)

1958-07-01

The first reactor built in Yugoslavia was the bare zero energy heavy water and natural uranium assembly at the Boris Kidric Institute of Nuclear Sciences, Belgrade. The reactor went critical on April 29, 1958. The possession of four tons of natural uranium metal and the temporary availability of seven tons of heavy water encouraged the staff of the Institute to build a critical assembly. A critical assembly was chosen, rather than high flux reactor, because the heavy water was available only temporarily. Besides, a 10 MW, enriched uranium, research reactor is being built at the same Institute and should be ready for operation late this year. It was supposed that the zero energy reactor would provide experience in carrying out critical experiments, operational experience with nuclear reactors, and the possibility for an extensive program in reactor physics. (author)

Heavy rain effects

Science.gov (United States)

Dunham, R. Earl, Jr.

1994-01-01

This paper summarizes the current state of knowledge of the effect of heavy rain on airplane performance. Although the effects of heavy rain on airplane systems and engines are generally known, only recently has the potential aerodynamic effect of heavy rain been recognized. In 1977 the United States Federal Aviation Administration (FAA) conducted a study of 25 aircraft accidents and incidents which occurred between 1964 and 1976 in which low-altitude wind shear could have been a contributing factor. Of the 25 cases (23 approach or landing and 2 take-off) in the study, ten cases had occurred in a rain environment, and in five cases these were classified as intense or heavy rain encounters. These results led to the reconsideration of high-intensity, short-duration rainfall as a potential weather-related aircraft safety hazard, particularly in the take-off and/or approach phases of flight.

Neutron disadvantage factors in heavy water and light water reactors

International Nuclear Information System (INIS)

Pop-Jordanov, J.

1966-01-01

A number od heavy water and light water reactor cells are analyzed in this paper by applying analytical methods of neutron thermalization. Calculations done according to the one-group Amouyal-Benoist method are included in addition. Computer codes for ZUSE Z-23 computer were written by applying both methods. The obtained results of disadvantage factors are then compared to results obtained by one-group P 3 approximation and by multigroup K7-THERMOS code [sr

On-line/on-site analysis of heavy metals in water and soils by laser induced breakdown spectroscopy

Science.gov (United States)

Meng, Deshuo; Zhao, Nanjing; Wang, Yuanyuan; Ma, Mingjun; Fang, Li; Gu, Yanhong; Jia, Yao; Liu, Jianguo

2017-11-01

The enrichment method of heavy metal in water with graphite and aluminum electrode was studied, and combined with plasma restraint device for improving the sensitivity of detection and reducing the limit of detection (LOD) of elements. For aluminum electrode enrichment, the LODs of Cd, Pb and Ni can be as low as several ppb. For graphite enrichment, the measurement time can be less than 3 min. The results showed that the graphite enrichment and aluminum electrode enrichment method can effectively improve the LIBS detection ability. The graphite enrichment method combined with plasma spatial confinement is more suitable for on-line monitoring of industrial waste water, the aluminum electrode enrichment method can be used for trace heavy metal detection in water. A LIBS method and device for soil heavy metals analysis was also developed, and a mobile LIBS system was tested in outfield. The measurement results deduced from LIBS and ICP-MS had a good consistency. The results provided an important application support for rapid and on-site monitoring of heavy metals in soil. (Left: the mobile LIBS system for analysis of heavy metals in soils. Top right: the spatial confinement device. Bottom right: automatic graphite enrichment device for on0line analysis of heavy metals in water).

Heavy metals concentrations in water bodies around aquamarine ...

African Journals Online (AJOL)

Water samples from three streams in the mining area of Eggon Hill were analysed. The Physicochemical values obtained were compared with WHO permissible standards in drinking water. Except for Cu and Zn with levels within permissible limits, other heavy metals determined were found to have levels above the WHO ...

Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon.

Science.gov (United States)

Sounthararajah, Danious P; Loganathan, Paripurnanda; Kandasamy, Jaya; Vigneswaran, Saravanamuthu

2015-08-27

Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC) and suspended solids (SS) are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA) (DOC representative), they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal) was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS) had no effect on Pb and Cu, but it did on the other metals.

Method for separation of water from bituminous shales, etc. [water-free heavy product and water-containing light product

Energy Technology Data Exchange (ETDEWEB)

Hellsing, G H

1908-10-13

The method is characterized by conducting all the products of distillation, coming from the retorts, into a controllable system of condensation. This system of condensation is so constructed that the products of distillation are cooled to such a temperature that only the water-free heavy distillates are being condensed, and is furthermore so constructed that the other products of distillation, not yet condensed, are being condensed in an ordinary system of coolers. The purpose is to separate the distillates into a water-free heavy product and a water-containing lighter product. The patent includes an additional claim.

Uncertainties in gas dispersion at the Bruce heavy water plant

International Nuclear Information System (INIS)

Alp, E.; Ciccone, A.

1995-07-01

There have been concerns regarding the uncertainties in atmospheric dispersion of gases released from the Bruce Heavy Water Plant (BHWP). The concern arises due to the toxic nature of H 2 S, and its combustion product SO 2 . In this study, factors that contribute to the uncertainties, such as the effect of the shoreline setting, the potentially heavy gas nature of H 2 S releases, and concentration fluctuations, have been investigated. The basic physics of each of these issues has been described along with fundamental modelling principles. Recommendations have been provided on available computer models that would be suitable for modelling gas dispersion in the vicinity of the BHWP. (author). 96 refs., 4 tabs., 25 figs

Uncertainties in gas dispersion at the Bruce heavy water plant

Energy Technology Data Exchange (ETDEWEB)

Alp, E; Ciccone, A [Concord Environmental Corp., Downsview, ON (Canada)

1995-07-01

There have been concerns regarding the uncertainties in atmospheric dispersion of gases released from the Bruce Heavy Water Plant (BHWP). The concern arises due to the toxic nature of H{sub 2}S, and its combustion product SO{sub 2}. In this study, factors that contribute to the uncertainties, such as the effect of the shoreline setting, the potentially heavy gas nature of H{sub 2}S releases, and concentration fluctuations, have been investigated. The basic physics of each of these issues has been described along with fundamental modelling principles. Recommendations have been provided on available computer models that would be suitable for modelling gas dispersion in the vicinity of the BHWP. (author). 96 refs., 4 tabs., 25 figs.

Development of a portable heavy-water leak sensor based on laser absorption spectroscopy

International Nuclear Information System (INIS)

Lee, Lim; Park, Hyunmin; Kim, Taek-Soo; Kim, Minho; Jeong, Do-Young

2016-01-01

Highlights: • We developed a compact and portable laser sensor for a detection of heavy water leakage. • The sensor is wearable and also easy to use to search for the leak point. • It is sensitive enough to find invisible very tiny leaks. - Abstract: A compact and portable leak sensor based on cavity enhanced absorption spectroscopy has been newly developed for a detection of heavy water leakage which may happen in the facilities using heavy water such as pressurized heavy water reactor (PHWR). The developed portable sensor is suitable as an individual instrument for the measuring leak rate and finding the leak location because it is sufficiently compact in size and weight and operated by using an internal battery. In the performance test, the minimum detectable leak rate was estimated as 0.05 g/day from the calibration curve. This new sensor is expected to be a reliable and promising device for the detection of heavy water leakage since it has advantages on real-time monitoring and early detection for nuclear safety.

Sediment, water pollution indicators for heavy metals

International Nuclear Information System (INIS)

Cabaleiro, S.; Horn, A.

2010-01-01

The complexity of an aquatic system requires consideration of its dynamics: spatial and temporal variations of physical, chemical and biological. Heavy metals have peculiar behavior in the aquatic system and may not be available in the waters, but on sediments.The sub-basin of the Sarandi stream is responsible for the contamination of Pampulha Lake. The Instituto Mineiro das Águas – IGAM - uses tool for monitoring the quality of surface water for developing strategies for conservation, restoration and rational use of water resources. So through the indices: IQA ( Indice de qualidade de águas) Index of water quality, and TC- toxic contamination, reduces conflicts, implements the disciplining of the environmental economy.This study determined the monitoring of sediment and water of Sarandi Stream, so in the samples collected during dry and rainy seasons (2007- 2008) were analyzed heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb) and physical-chemical factors (conductivity, solids dissolved, temperature, turbidity). This allowed the determination of Hackanson factors of contamination and Muller Index geoaccumulation, indicating very high contamination in sediments regarding the elements Cr, Cu, and Cd, and high contamination for Pb, Zn, and Mn. The comparison with the indices of water quality- IQA (IGAM - 2006, 2007 and 2008), combined with exploratory data analysis and graphs of correlation between the variables indicated favorable conditions for metals contamination on water and sediment for these metals, besides allowing the identification of its source

Novel biopolymer-coated hydroxyapatite foams for removing heavy-metals from polluted water

International Nuclear Information System (INIS)

Vila, M.; Sanchez-Salcedo, S.; Cicuendez, M.; Izquierdo-Barba, I.; Vallet-Regi, Maria

2011-01-01

Highlights: → 3D-macroporous biopolymer-coated hydroxyapatite (HA) foams as potential devices for the treatment of heavy metal ions. → HA stable foams coated with biopolymers. → Feasible advance in development of new, easy to handle and low cost water purifying methods. - Abstract: 3D-macroporous biopolymer-coated hydroxyapatite (HA) foams have been developed as potential devices for the treatment of lead, cadmium and copper contamination of consumable waters. These foams have exhibited a fast and effective ion metal immobilization into the HA structure after an in vitro treatment mimicking a serious water contamination case. To improve HA foam stability at contaminated aqueous solutions pH, as well as its handling and shape integrity the 3D-macroporous foams have been coated with biopolymers polycaprolactone (PCL) and gelatine cross-linked with glutaraldehyde (G/Glu). Metal ion immobilization tests have shown higher and fast heavy metals captured as function of hydrophilicity rate of biopolymer used. After an in vitro treatment, foam morphology integrity is guaranteed and the uptake of heavy metal ions rises up to 405 μmol/g in the case of Pb 2+ , 378 μmol/g of Cu 2+ and 316 μmol/g of Cd 2+ . These novel materials promise a feasible advance in development of new, easy to handle and low cost water purifying methods.

Critical evaluation of heavy water project at Thal (Preprint No. PM-5)

International Nuclear Information System (INIS)

Jayakumar, N.S.

1989-04-01

The project known as Thal Ammonia Extension was a heavy water project successfully completed by Rashtriya Chemicals and Fertilizers (RCF) Ltd. The project consisted of erecting a heavy water plant of 110 tons/year capacity at Thal. The process Know-how and engineering of the plant was supplied by the Heavy Water Projects Division of the Department of Atomic Energy. Salient features of the project, management features which resulted in fast completion of erection, bottlenecks faced and engineering innovations adopted for efficient operation of the plant are described. Some modifications which can lead to smoother operation are listed. (M.G.B.)

Heavy baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Koerner, J.G.; Thompson, G.

1991-10-01

We give a mini-review of recent results on current-induced transitions between heavy baryons (and between heavy and light baryons) in the light of the new spin and flavour symmetries of the Heavy Quark Effective Theory (HQET). We discuss the structure of the 1/m corrections to the heavy mass limit and outline a diagrammatic proof that there are no 0(1/m) correction to the Voloshin-Shifman normalization condition at zero recoil. (orig.)

Turning the volume down on heavy metals using tuned diatomite. A review of diatomite and modified diatomite for the extraction of heavy metals from water

International Nuclear Information System (INIS)

Danil de Namor, Angela F.; El Gamouz, Abdelaziz; Frangie, Sofia; Martinez, Vanina; Valiente, Liliana; Webb, Oliver A.

2012-01-01

Highlights: ► Critical assessment of published work on raw and modified diatomites. ► Counter-ion effect on the extraction of heavy metal speciation by diatomite. ► Selection of the counter-ion by the use of existing thermodynamic data. ► Enrichment of diatomites by attaching heavy metal selective functionalities. ► Supramolecular chemistry for conferring selectivity to diatomites. - Abstract: Contamination of water by heavy metals is a global problem, to which an inexpensive and simple solution is required. Within this context the unique properties of diatomite and its abundance in many regions of the world have led to the current widespread interest in this material for water purification purposes. Defined sections on articles published on the use of raw and modified diatomite for the removal of heavy metal pollutants from water are critically reviewed. The capability of the materials as extracting agents for individual species and mixtures of heavy metals are considered in terms of the kinetics, the thermodynamics and the recyclability for both, the pollutant and the extracting material. The concept of ‘selectivity’ for the enrichment of naturally occurring materials such as diatomite through the introduction of suitable functionalities in their structure to target a given pollutant is emphasised. Suggestions for further research in this area are given.

Heavy quark effective theory and study of heavy hadron spectra

International Nuclear Information System (INIS)

Dong Yubing

1995-01-01

By employing the heavy quark effective theory, the spectra of heavy hadrons, such as heavy mesons (Q-barq), heavy baryons (QQq and Qqq) and heavy multiquark systems (Q-barQ-barqq) are studied systemically. The results are compared with the predictions for Q-barQ-barqq in potential model

Phytoremediation of heavy metal-contaminated water and sediment by eleocharis acicularis

Energy Technology Data Exchange (ETDEWEB)

Sakakibara, Masayuki; Ha, Nguyen Thi Hoang [Graduate School of Science and Engineering, Ehime University, Matsuyama (Japan); Ohmori, Yuko [Graduate School of Science and Engineering, Ehime University, Matsuyama (Japan); Taisei Kiso Sekkei Co., Ltd., Tokyo (Japan); Sano, Sakae [Faculty of Education, Ehime University, Matsuyama (Japan); Sera, Koichiro [Cyclotron Center, Iwate Medical University, Takizawa-mura (Japan)

2011-08-15

Phytoremediation is an environmental remediation technique that takes advantage of plant physiology and metabolism. The unique property of heavy metal hyperaccumulation by the macrophyte Eleocharis acicularis is of great significance in the phytoremediation of water and sediments contaminated by heavy metals at mine sites. In this study, a field cultivation experiment was performed to examine the applicability of E. acicularis to the remediation of water contaminated by heavy metals. The highest concentrations of heavy metals in the shoots of E. acicularis were 20 200 mg Cu/kg, 14 200 mg Zn/kg, 1740 mg As/kg, 894 mg Pb/kg, and 239 mg Cd/kg. The concentrations of Cu, Zn, As, Cd, and Pb in the shoots correlate with their concentrations in the soil in a log-linear fashion. The bioconcentration factor for these elements decreases log-linearly with increasing concentration in the soil. The results indicate the ability of E. acicularis to hyperaccumulate Cu, Zn, As, and Cd under natural conditions, making it a good candidate species for the phytoremediation of water contaminated by heavy metals. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Assessment of heavy metals concentration in drinking water ...

African Journals Online (AJOL)

The concentration of all the metals were considerably found to be below the limit permitted by WHO's drinking water guidelines (WHO 2005). Findings suggest that continues water quality monitoring should be carried out to check the concentration levels of heavy metals in that area, to prevent them from been above the limit ...

Analysis of hydrogen sulfide releases in heavy water production facilities

International Nuclear Information System (INIS)

Croitoru, Cornelia; Dumitrescu, Maria; Preda, Irina; Lazar, Roxana

1996-01-01

Safety analyses conducted at ICIS concern primarily the heavy water production installations. The quantitative risk assessment needs the frequency calculation of accident sequences and consequences. In heavy water plants which obtain primary isotopic concentration of water by H 2 O - H 2 S exchange, large amounts of hydrogen sulfide which is a toxic, inflammable and explosive gas, are circulated. The first stage in calculating the consequences consists in potential analysis of H 2 S release. This work presents a study of this types of releases for pilot installations of the heavy water production at ICIS (Plant 'G' at Rm. Valcea). The installations which contain and maneuver large quantities of H 2 S and the mathematical models for different types of releases are presented. The accidents analyzed are: catastrophic column, container, spy-hole failures or gas-duct rupture and wall cracks in the installation. The main results are given as tables while the time variations of the flow rate and quantities of H 2 O released by stack disposal are plotted

Parametric studies to establish natural circulation in advanced heavy water reactor

Energy Technology Data Exchange (ETDEWEB)

Bhatia, S K; Dhawan, M L [Reactor Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Design of Advanced Heavy Water Reactor (AHWR) is in progress. It consists of vertical pressure tubes with boiling light water coolant flowing through the tubes and heavy water moderator in the calandria. In PHWRs, core heat removal is through forced circulation of the coolant by PHT pumps. In AHWR, no PHT pumps are used and core heat is carried away by natural circulation of the coolant due to density difference between steam/water mixture inside the core and the water region outside the core. This passive means of core heat removal results in a number of benefits viz. (a) extra length of piping, valves, instruments, power supply and control systems for functioning of instruments are eliminated, (b) plant layout is simplified, (c) maintenance of valves and instruments is reduced. Natural circulation in AHWR is achieved by keeping the steam drum at a sufficient height above the core to get the required driving force. The loop height depends on many factors i.e. channel power, V{sub c}/V{sub f} ratio (ratio of coolant volume to fuel volume) and core height. The effect of these parameters on the loop height to establish natural circulation have been studied and presented. (author). 1 ref., 1 fig., 1 tab.

Supercritical water treatment of heavy metal and arsenic metalloid-bioaccumulating-biomass.

Science.gov (United States)

Li, Jianxin; Chen, Jinbo; Chen, Shan

2018-08-15

Hyperaccumulator biomass, as a promising resource for renewable energy that can be converted into valuable fuel productions with high conversion efficiency, must be considered as hazardous materials and be carefully treated before further reuse due to the high contents of heavy metals. In this study, Pteris vittata L., an As-hyperaccumulator biomass was treated by an effective and environmental friendly method-supercritical water gasification (SCWG) using a bench-scale batch reactor. The contents of heavy metals (Cd, Pb and Zn) and arsenic metalloid in solid, liquid and gaseous products during SCWG process were thoroughly investigated. The speciation fractions including exchangeable, reducible, oxidizable and residual fractions of each heavy metal as the proportion of the total contents in solid residue were presented and the transformations trend of these heavy metals during the SCWG process was especially demonstrated. The significant operating parameters, including reaction temperature (395-445 °C), pressure (21-27 MPa) and residence time (0-40 min) were varied to explore their effects on the contents and forms. Moreover, the environmental risks of heavy metals in solid residues were evaluated based on risk assessment code, taking into consideration the speciation fractions and bioavailability. It was highlighted that although heavy metals particularly Pb and Zn tended to accumulate in solid residues with a maximum increment of about 50% in the total content, they were mostly converted to more stable oxidizable and residual fractions, and thus the ecotoxicity and bioavailability were greatly mitigated with no obvious increase in direct toxicity fractions. Each tested heavy metal presented no or low risk to the environments after SCWG treatments, meaning that the environmental pollution levels were markedly reduced with no or low risk to the environment. This study highlights the remarkable ability of SCWG for the heavy metal stabilization. Copyright �

Thorium utilization in heavy water moderated Accelerator Driven Systems

International Nuclear Information System (INIS)

Bajpai, Anil; Degweker, S.B.; Ghosh, Biplab

2011-01-01

Research on Accelerator Driven Systems (ADSs) is being carried out around the world primarily with the objective of waste transmutation. Presently, the volume of waste in India is small and therefore there is little incentive to develop ADS based waste transmutation technology immediately. With limited indigenous U availability and the presence of large Th deposits in the country, there is a clear incentive to develop Th related technologies. India also has vast experience in design, construction and operation of heavy water moderated reactors. Heavy water moderated reactors employing solid Th fuels can be self sustaining, but the discharge burnups are too low to be economical. A possible way to improve the performance such reactors is to use an external neutron source as is done in ADS. This paper discusses our studies on Th utilization in heavy water moderated ADSs. The study is carried out at the lattice level. The time averaged k-infinity of the Th bundle from zero burnup up to the discharge burnup is taken to be the same as the core (ensemble) averaged k-infinity. For the purpose of the analysis we have chosen standard PHWR and AHWR assemblies. Variation of the pitch and coolant (H 2 O/D 2 O) are studied. Both, the once through cycle and the recycling option are studied. In the latter case the study is carried out for various enrichments (% 233 U in Th) of the recycled Th fuel bundles. The code DTF as modified for lattice and burnup calculations (BURNTRAN) was used for carrying out the study. The once through cycle represents the most attractive ADS concept (Th burner ADS) possible for Th utilization. It avoids reprocessing of Th spent fuel and in the ideal situation the use of any fissile material either initially or for sustaining itself. The gain in this system is however rather low requiring a high power accelerator and a substantial fraction of the power generated to be fed back to the accelerator. The self sustaining Th-U cycle in a heavy moderated ADS

Feasibility study and economic analysis on thorium utilization in heavy water reactors

International Nuclear Information System (INIS)

1978-07-01

Even though natural uranium is a more easily usable fuel in heavy water reactors, thorium fuel cycles have also been considered owing to certain attractive features of the thorium fuel cycle in heavy water reactors. The relatively higher fission neutron yield per thermal neutron absorption in 233 U combined with the very low neutron absorption cross section of heavy water make it possible to achieve breeding in a heavy water reactor operating on Th- 233 U fuel cycle. Even if the breeding ratio is very low, once a self-sustaining cycle is achieved, thereafter dependence on uranium can be completely eliminated. Thus, with a self-sustaining Th- 233 U fuel cycle in heavy water reactors, a given quantity of natural uranium will be capable of supporting a much larger installed generating capacity to significantly longer period of time. However, since thorium does not contain any fissile isotope, fissile material has to be added at the beginning. Concentrated fissile material is considerably more expensive than the 235 U contained in natural uranium. This makes the fuel cycle cost higher with thorium fuel cycle, at least during the initial stages. The situation is made worse by the fact that, because of its higher thermal neutron absorption cross section, thorium requires a higher concentration of fissile material than 238 U. Nevertheless, because of the superior nuclear characteristics of 233 U, once uranium becomes more expensive, thorium fuel cycle in heavy water reactors may become economically acceptable. Furthermore, the energy that can be made available from a given quantity of uranium is considerably increased with a self-sustaining thorium fuel cycle

Effects of Hyporheic Water Fluxes and Sediment Grain Size on the Concentration and Diffusive Flux of Heavy Metals in the Streambed.

Science.gov (United States)

Liu, Qi; Song, Jinxi; Zhang, Guotao; Wang, Weize; Guo, Weiqiang; Tang, Bin; Kong, Feihe; Huo, Aidi

2017-09-06

The hyporheic zone regulates physicochemical processes in surface-groundwater systems and can be an important source of heavy metals in fluvial systems. This study assesses the pore water concentrations and diffusive fluxes of heavy metals with respect to the vertical water exchange flux (VWEF) and sediment grain size. Water and sediment samples were collected on August 2016 from upstream Site 1 and downstream Site 2 along the Juehe River in Shaanxi Province, China. Streambed vertical hydraulic conductivity (Kv) and the VWEF were estimated via the standpipe permeameter test method and Darcy's law. The heavy metal concentrations in the pore water were measured and the diffusive fluxes were calculated using Fick's first law. The VWEF patterns were dominated by upward flow, and Site 1 featured higher values of Kv and VWEF. Higher Cu and Zn concentrations occurred near the channel centre with coarse sand and gravel and greater upward VWEFs because coarser sediment and greater upward VWEFs cause stronger metal desorption capacity. Additionally, Cu and Zn at the two sites generally diffused from pore water to surface water, potentially due to the upward VWEF. The VWEF and sediment grain size are likely crucial factors influencing the heavy metal concentrations and diffusive fluxes.

Numerical Simulation Study on Steam-Assisted Gravity Drainage Performance in a Heavy Oil Reservoir with a Bottom Water Zone

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Jun Ni

2017-12-01

Full Text Available In the Pikes Peak oil field near Lloydminster, Canada, a significant amount of heavy oil reserves is located in reservoirs with a bottom water zone. The properties of the bottom water zone and the operation parameters significantly affect oil production performance via the steam-assisted gravity drainage (SAGD process. Thus, in order to develop this type of heavy oil resource, a full understanding of the effects of these properties is necessary. In this study, the numerical simulation approach was applied to study the effects of properties in the bottom water zone in the SAGD process, such as the initial gas oil ratio, the thickness of the reservoir, and oil saturation of the bottom water zone. In addition, some operation parameters were studied including the injection pressure, the SAGD well pair location, and five different well patterns: (1 two corner wells, (2 triple wells, (3 downhole water sink well, (4 vertical injectors with a horizontal producer, and (5 fishbone well. The numerical simulation results suggest that the properties of the bottom water zone affect production performance extremely. First, both positive and negative effects were observed when solution gas exists in the heavy oil. Second, a logarithmical relationship was investigated between the bottom water production ratio and the thickness of the bottom water zone. Third, a non-linear relation was obtained between the oil recovery factor and oil saturation in the bottom water zone, and a peak oil recovery was achieved at the oil saturation rate of 30% in the bottom water zone. Furthermore, the operation parameters affected the heavy oil production performance. Comparison of the well patterns showed that the two corner wells and the triple wells patterns obtained the highest oil recovery factors of 74.71% and 77.19%, respectively, which are almost twice the oil recovery factors gained in the conventional SAGD process (47.84%. This indicates that the optimized SAGD process

Method of extracting tritium from heavy water

International Nuclear Information System (INIS)

Tsuchiya, Hiroyuki; Kikuchi, Makoto; Asakura, Yamato; Yusa, Hideo.

1979-01-01

Purpose: To extract tritium in heavy water by combining isotope exchange reaction with liquefaction distillation to increase the concentration of recovered tritium, thereby reducing the quantity of radioactive wastes recovered. Constitution: Heavy water containing tritium from a reactor is introduced into a tritium separator through a conduit pipe. On the other hand, a D 2 gas is introduced through the conduit pipe in the lower part of a tritium separator to transfer tritium into D 2 gas by isotope exchange. The D 2 gas containing DT is introduced into a liquefaction distillation tower together with an outlet gas of a converter supplied through a pipeline. The converter is filled with net-like metals of platinum group such as Pt, Ni, Pd and the like, and the D 2 gas affluent in DT, extracted from the distillation tower is converted into D 2 and T 2 . The gas which has been introduced into the liquefaction distillation tower is liquefied. The D 2 gas of low boiling point components reaches the tower top, and the T 2 gas of high boiling point components is concentrated at the tower bottom, and is rendered into tritium water in a recoupler and stored in a water storage apparatus. (Yoshino, Y.)

The projects for heavy water production of the Argentine National Atomic Energy Commission

International Nuclear Information System (INIS)

Garcia Bourg, J.M.; Garcia, E.E.

1982-01-01

The bases and scope of the projects for heavy water production that are being currently developed by the Argentine National Atomic Energy Commission (CNEA) are described. As an introduction, the following points are presented: a) the fundamentals of heavy water utilization in a nuclear reactor, with a mention of its properties and uses, b) a review of the physicochemical bases of the principal methods for heavy water production: chemical exchange (monothermal and bithermal processes), distillation and electrolysis, with tables summarizing the fundamental characteristics of the first two ones, and an evaluation of the different production methods from the viewpoint of their application in an industrial scale; and c) a synthetic information, in the form of tables, about the world's heavy water production. The subject of heavy water production in Argentina is treated in the principal section, describing the scope, location, main characteristics and chemical processes corresponding to the projects being developed by CNEA, which currently are the installation of an Industrial Plant in Arroyito (Province of Neuquen), purchased on a turnkey basis and using the NH 3 /H 2 isotopic exchange method; the installation of an Experimental Plant in Atucha (Province of Buenos Aires), for the development of the domestic technology of heavy-water production by the SH 2 /H 2 O isotopic exchange method, and the development of the engineering of an industrial plant (''Module 80''), based on the Experimental Plant's technology. (M.E.L.) [es

Safety Evaluation of Osun River Water Containing Heavy Metals and ...

African Journals Online (AJOL)

Summary: This study evaluated the pH, heavy metals and volatile organic compounds (VOCs) in Osun river water. It also evaluated its safety in rats. Heavy metals were determined by atomic absorption spectrophotometry (AAS) while VOCs were determined by gas chromatography coupled with flame ionization detector ...

Assessment of Heavy Metals in the Water of Sahastradhara Hill Stream at Dehradun, India

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Pawan Kumar Bharti

2014-09-01

Full Text Available A study on heavy metals assessment in the water of Sahastradhara hill-stream was conducted with different five sites at significant differences. The present paper deals with the water quality status of Sahastradhara stream by the assessment of heavy metals. Heavy Metals were found in fluctuated trend from first upstream to last downstream. The values of almost all Heavy Metals were found in increasing manner especially after the fourth sampling site. After the third sampling station, a solid waste dumping site was found. So, there may be a relation between heavy metals in stream water and solid waste dumping site. Concentrations of all Heavy Metals at fourth and fifth sampling site were found very high. DOI: http://dx.doi.org/10.3126/ije.v3i3.11076 International Journal of Environment Vol.3(3 2014: 164-172

Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon

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Danious P. Sounthararajah

2015-08-01

Full Text Available Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC and suspended solids (SS are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA (DOC representative, they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS had no effect on Pb and Cu, but it did on the other metals.

Pulse radiolysis studies of liquid heavy water at temperatures up to 250 degrees C

International Nuclear Information System (INIS)

Stuart, C.R.; Ouellette, D.C.; Elliot, A.J.

2002-09-01

This report documents the rate constants and associated activation energies for the reactions of the primary radical species, e aq - , ·OD and ·D, which are formed during the radiolysis of heavy water within the temperature range 20 to 250 o C. These heavy-water data have been compared with the corresponding information for light water. These kinetic data form part of the database that is required to model the aqueous radiation chemistry that occurs within the core of the heavy water cooled and moderated CANDU reactor. (author)

Pulse radiolysis studies of liquid heavy water at temperatures up to 250 degrees C

Energy Technology Data Exchange (ETDEWEB)

Stuart, C.R.; Ouellette, D.C.; Elliot, A.J

2002-09-01

This report documents the rate constants and associated activation energies for the reactions of the primary radical species, e{sub aq}{sup -}, {center_dot}OD and {center_dot}D, which are formed during the radiolysis of heavy water within the temperature range 20 to 250 {sup o}C. These heavy-water data have been compared with the corresponding information for light water. These kinetic data form part of the database that is required to model the aqueous radiation chemistry that occurs within the core of the heavy water cooled and moderated CANDU reactor. (author)

The Battle for Heavy Water Three physicists' heroic exploits

CERN Multimedia

2002-01-01

Up until the end of the 1970s you could still catch a glimpse of his massive silhouette in the corridors of CERN. Lew Kowarksi, one of the pioneers of the Laboratory, was not only a great physicist; he was also a genuine hero of World War II. In 1940, along with Frédéric Joliot and Hans von Halban, Lew Kowarski managed to get the entire world supply of heavy water away to safety from the Nazis after a fantastic escape from occupied France. At the end of the war, the three physicists played themselves in a film about their adventures entitled 'la Bataille de l'eau lourde'. This film, which has been loaned to us by the French National Film Library, will be shown at CERN for the first time next Thursday. At the beginning of the war, heavy water (D20, two atoms of deuterium and one oxygen atom) was of strategic importance. In 1939 Frédéric Joliot, aided by Hans von Halban and Lew Kowarski, demonstrated the nuclear chain reaction and the moderator role that heavy water plays in it. A few weeks before the inv...

The importance of heavy water in nuclear technology

International Nuclear Information System (INIS)

Gharib, A.G.

2004-01-01

Due to similarities of chemical and almost physical properties in H 2 O and D 2 O but differences in nuclear and particle peculiarities provide valuable application for D 2 O. To sustain a controlled chain reaction, the energy of neutrons produced by fission must be reduced through collisions with other nuclei, a process called moderation. A good moderator has a mass close to that of the neutron to maximize energy loss per collision and a very small neutron capture cross section to minimize unwanted nuclear reactions. Deuterium is far the best moderator, more than 80 times better than hydrogen and 30 times better than 12 C ir 18 O. Heavy water is almost as good as deuterium and has the distinct advantage of being a nonflammable liquid. Heavy water is also an excellent neutron reflector, and thus decreases the number of neutrons that escape the reactor core without participating in fission reactions. For this reason a feasibility study and subsequently a technical survey was carried out on engineering of a pilot scale plant. As the result of this studies, the know-how of heavy water production on basis of selected method including dual temperature isotopic exchange and distillation techniques developed. Subsequently the primary and almost detail engineering documents prepared on best knowledge of our own engineers without external contribution

Turning the volume down on heavy metals using tuned diatomite. A review of diatomite and modified diatomite for the extraction of heavy metals from water

Energy Technology Data Exchange (ETDEWEB)

Danil de Namor, Angela F., E-mail: A.Danil-De-Namor@surrey.ac.uk [Instituto Nacional de Tecnologia Industrial, Parque Tecnologico Industrial Miguelete, Buenos Aires (Argentina); Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); El Gamouz, Abdelaziz [Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Frangie, Sofia; Martinez, Vanina; Valiente, Liliana [Instituto Nacional de Tecnologia Industrial, Parque Tecnologico Industrial Miguelete, Buenos Aires (Argentina); Webb, Oliver A. [Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2012-11-30

Highlights: Black-Right-Pointing-Pointer Critical assessment of published work on raw and modified diatomites. Black-Right-Pointing-Pointer Counter-ion effect on the extraction of heavy metal speciation by diatomite. Black-Right-Pointing-Pointer Selection of the counter-ion by the use of existing thermodynamic data. Black-Right-Pointing-Pointer Enrichment of diatomites by attaching heavy metal selective functionalities. Black-Right-Pointing-Pointer Supramolecular chemistry for conferring selectivity to diatomites. - Abstract: Contamination of water by heavy metals is a global problem, to which an inexpensive and simple solution is required. Within this context the unique properties of diatomite and its abundance in many regions of the world have led to the current widespread interest in this material for water purification purposes. Defined sections on articles published on the use of raw and modified diatomite for the removal of heavy metal pollutants from water are critically reviewed. The capability of the materials as extracting agents for individual species and mixtures of heavy metals are considered in terms of the kinetics, the thermodynamics and the recyclability for both, the pollutant and the extracting material. The concept of 'selectivity' for the enrichment of naturally occurring materials such as diatomite through the introduction of suitable functionalities in their structure to target a given pollutant is emphasised. Suggestions for further research in this area are given.

Direct harvesting of Helium-3 (3He) from heavy water nuclear reactors

International Nuclear Information System (INIS)

Bentoumi, G.; Didsbury, R.; Jonkmans, G.; Rodrigo, L.; Sur, B.

2013-01-01

The thermal neutron activation of deuterium inside a heavy-water-moderated or -cooled nuclear reactor produces a build-up of tritium in the heavy water. The in situ decay of tritium can, for certain reactor types and operating conditions, produce potentially useable amounts of 3 He, which can be directly extracted via the heavy-water cover gas without first separating, collecting and storing tritium outside the reactor. It is estimated that the amount of 3 He available for recovery from the moderator cover gas of a 700 MWe class Pressurized Heavy Water Reactor (PHWR) ranges from 0.1 to 0.7 m 3 (STP) per annum, varying with the tritium activity buildup in the moderator. The harvesting of 3 He would generate approximately 12.7 m 3 (STP) of 3 He, worth more than $30M at current market rates, over a typical 25-year operating cycle of the PHWR. This paper discusses the production of 3 He in the moderator of a PHWR and its extraction from the 4 He moderator cover gas system using conventional methods. (author)

SURFACE WATER POLLUTION WITH HEAVY METALS IN THE LOWER CATCHMENT OF JIU RIVER BASIN, ACCORDING TO THE WATER FRAMEWORK DIRECTIVE (2000/60/EC

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ADINA SANDA ŞERBAN

2011-03-01

Full Text Available Surface water pollution with heavy metals in the lower catchment of Jiu river basin, according to the Water Framework Directive (2000/60/EC. The Water Framework Directive establishes a single transparent, effective and coherent water policy by defining a strategy to combat pollution by requiring specific action programs.Chemical pollution of surface water presents a threat to the aquatic environment with acute and chronic toxicity to aquatic organisms, accumulation in the ecosystem and losses of habitats and biodiversity, as well as a threat to human health (art.1 from Directive 2008/105/EC regarding the environmental quality standards for water policy.The purpose of this study is to evaluate the chemical status for surface water bodies in the lower catchment of Jiu river basin. The assessment was made taking into account the water impact of four heavy metals: cadmium (Cd, nickel (Ni, mercury (Hg and lead (Pb.

Special operations in the heavy water system, III-2; III-2 Posebne operacije u sistemu teske vode

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-07-01

Special operations in the heavy water system described in this chapter are as follows: treatment, drainage and pouring of heavy water, emptying of the heavy water system, cleaning and vacuuming of the heavy water system. [Serbo-Croat] Posebne operacije u sistemu teske vode opisane u ovom poglavlju su: tretiranje, dreniranje i razlivanje teske vode, praznjenje sistema teske vode, 'ispiranje' i vakumiranje sistema teske vode.

Improvements on heavy water separation technology by isotopic water-hydrogen sulfide exchange

International Nuclear Information System (INIS)

Peculea, M.

1987-01-01

A series of possible variance is presented for the heavy water separation technology by isotopic H 2 O-H 2 S exchange at dual temperatures. The critical study of these variants, which are considered as characteristic quantities for the isotopes transport (production) and the extraction level is related to a dual temperature plant fed by liquid and cold column, which is the up-to-date technology employed in all heavy water production plants as variants of following plants are studied: dual temperature plant with double feeding; dual-temperature plant with equilibrium column (booster); dual-temperature-dual-pressure plant. Attention is paid to the variant with equilibration column (booster), executed and tested at the State Committee for Nuclear Energy and to the dual-temperature-dual pressure plant which presents the highest efficiency. (author)

Surface Water Modeling Using an EPA Computer Code for Tritiated Waste Water Discharge from the heavy Water Facility

International Nuclear Information System (INIS)

Chen, K.F.

1998-06-01

Tritium releases from the D-Area Heavy Water Facilities to the Savannah River have been analyzed. The U.S. EPA WASP5 computer code was used to simulate surface water transport for tritium releases from the D-Area Drum Wash, Rework, and DW facilities. The WASP5 model was qualified with the 1993 tritium measurements at U.S. Highway 301. At the maximum tritiated waste water concentrations, the calculated tritium concentration in the Savannah River at U.S. Highway 301 due to concurrent releases from D-Area Heavy Water Facilities varies from 5.9 to 18.0 pCi/ml as a function of the operation conditions of these facilities. The calculated concentration becomes the lowest when the batch releases method for the Drum Wash Waste Tanks is adopted

Design of Heavy Metals Monitoring System in Water Based on WSN and GPRS

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Ke Lin

2014-04-01

Full Text Available In order to realize the real-time monitoring of heavy metals in water environment, a new type of heavy metal monitoring system was developed. The system was composed of monitoring terminal, gateway, GPRS network and upper computer monitoring center. The system detected the heavy metal ion concentrations by ion-selective electrode array and came into the system error automatic compensation method in the detection process. The collecting data was transported to the monitoring center through the cooperation between the wireless sensor network constituted by CC2530 and General Packet Radio Service network. The test result shows that the system can increased precision dramatically and strengthens the real-time transmission capacity effectively. The system is reliable in transmission, high real-time performance, flexible in networking and can be applied to continuous remote monitoring of heavy metals pollution.

Commissioning performance activities of Heavy Water Plant (Hazira) (Paper No. 1.4)

International Nuclear Information System (INIS)

Anon.

1992-01-01

Heavy Water Plant, Hazira is the fourth in the line of plants based on monothermal NH 3 -H 2 exchange process. The experience gained during operation of other heavy water plants is reflected in the construction, commissioning and operation of HWP, Hazira. This paper aims at outlining the strategy adopted for both commissioning and operation. (author)

Programmable logic controllers in Heavy Water Project, Manuguru (Paper No. 3.4)

International Nuclear Information System (INIS)

Gupta, S.C.; Bhaskar, R.; Maiti, A.; Venkatesu, G.; Satish, P.; Goel, R.K.

1992-01-01

Enhancement to plant operational flexibility has been achieved in Heavy Water Project, Manuguru by installing programmable logic controllers for its control equipment. The earlier sulfide based Heavy Water Plant, Kota is using relay logic and diode based program-matrix for binary controls. Performance improvement and advantages of PLC and experience in its operation are described. (author). 3 refs

Features in ammonia plant for maximising heavy water production (Paper No. 2.10)

International Nuclear Information System (INIS)

Tangri, N.N.; Singh, R.J.; Mukherjee, P.K.; Mishra, B.N.

1992-01-01

Whenever an ammonia plant is linked with heavy water production, a system should be foreseen in the design stage itself for total conservation of D 2 in synthesis gas and zero D 2 loss. The process should ensure recycle of D 2 rich condensate within the front end. This alone would be the single most important factor for improving heavy water production rate. The synthesis loop pressure should be chosen keeping in view the interest of heavy water plant (HWP). With vast experience in engineering NH 3 and HWP plants, it is possible to integrate HWP requirements at the design stage itself. (author)

Urban water pollution by heavy metals and health implication in ...

African Journals Online (AJOL)

Studies of common heavy metals were conducted at Onitsha, Anambra State, the most urbanized city in Southeastern Nigeria. It was discovered that both surface and subsurface water were heavily polluted. Seven (7) heavy metals namely: arsenic (As+2), cadmium (Cd+2), lead (Pb+2), mercury (Hg+2), zinc (Zn+2), copper ...

General description of advanced heavy water reactor

International Nuclear Information System (INIS)

Kakodkar, A.; Sinha, R.K.; Dhawan, M.L.

1999-01-01

Advanced Heavy Water Reactor is a boiling light water cooled, heavy water moderated and vertical pressure tube type reactor with its design optimised for utilisation of thorium for power generation. The core consists of (Th-U 233 )O 2 and (Th-Pu)O 2 fuel with a discharge burn up of 20,000 MWd/Te. This reactor incorporates several features to simplify the design, which eliminate certain systems and components. AHWR design is also optimised for easy replaceability of coolant channels, facilitation of in-service inspection and maintenance and ease of erection. The AHWR design also incorporates several passive systems for performing safety-related functions in the event of an accident. In case of LOCA, emergency coolant is injected through 4 accumulators of 260 m 3 capacity directly into the core. Gravity driven water pool of capacity 6000 m 3 serves to cool the core for 3 days without operator's intervention. Core submergence, passive containment isolation and passive containment cooling are the added features in AHWR. The paper describes the various process systems, core and fuel design, primary components and safety concepts of AHWR. Plant layout and technical data are also presented. The conceptual design of the reactor has been completed, and the detailed design and development is scheduled for completion in the year 2002. (author)

Heavy-water extraction from non-electrolytic hydrogen streams

International Nuclear Information System (INIS)

LeRoy, R.L.; Hammerli, M.; Butler, J.P.

1981-01-01

Heavy water may be produced from non-electrolytic hydrogen streams using a combined electrolysis and catalytic exchange process. The method comprises contacting feed water in a catalyst column with hydrogen gas originating partly from a non-electrolytic hydrogen stream and partly from an electrolytic hydrogen stream, so as to enrich the feed water with the deuterium extracted from both the non-electrolytic and electrolytic hydrogen gas, and passing the deuterium water to an electrolyser wherein the electrolytic hydrogen gas is generated and then fed through the catalyst column. (L.L.)

Environmental health scoping study at Bruce Heavy Water Plant

International Nuclear Information System (INIS)

Prior, M.; Mostrom, M.; Coppock, R.; Florence, Z.

1995-10-01

There are concerns that hydrogen sulfide released from the Heavy Water Plant near Kincardine, Ontario may be the cause of the mortalities and morbidities observed in a nearby flock of sheep. The Philosopher's Wool sheep farm is about four kilometres south-southeast of the Bruce Heavy Water Plant. Ontario Hydro, the owner and operator of the Bruce Heavy Water Plant, claims that hydrogen sulphide emissions from the Bruce Heavy Water Plant are within regulatory limits and well below levels that cause harm. Accordingly, the Atomic Energy Control Board commissioned the Alberta Environmental Centre, Alberta Department of Environmental Protection, to develop a scoping study for this environmental health issue. The first objective was to describe a field investigation model to define clearly the environmental health and operation of the sheep farm. The second objective was to describe possible exposure patterns and develop a holistic environmental pathway model. If appropriate, the third study objective was to describe animal models of the actual situation to elucidate specific aspects of the environmental health concerns. It was not the objective of this report to provide a definitive answer to the present environmental health issue. Ontario Hydro provided data to the Alberta Environmental Centre, as di the sheep farmer, the attending veterinarian, the University of Guelph study team, and the Atomic Energy Control Board. A six-tiered strategy of sequential evaluations of the ovine health problem is based on the multiple-response paradigm. It assumes the observed ovine health results are the result of multiple effector events. Each tier constitutes a separate, but inter-related, study. Sequential evaluation and feedback of each tier allow sound scientific judgements and efficient use of resources. (author). 59 refs., 11 tabs., 22 figs

Heavy metals in a degraded soil treated with sludge from water treatment plant

Directory of Open Access Journals (Sweden)

Teixeira Sandra Tereza

2005-01-01

Full Text Available The application of water treatment sludge (WTS to degraded soil is an alternative for both residue disposal and degraded soil reclaim. This study evaluated effects of the application of water treatment sludge to a Typic Hapludox soil degraded by tin mining in the National Forest of Jamari, State of Rondonia, Brazil, on the content of heavy metals. A completely randomized experimental design with five treatments was used: control (n = 4; chemical control, which received only liming (n = 4; and rates D100, D150 and D200, which corresponded to 100, 150 and 200 mg of N-sludge kg-1 soil (n = 20, respectively. Thirty days after liming, period in which soil moisture was kept at 70% of the retention capacity, soil samples were taken and analyzed for total and extractable Fe, Cu, Mn, Zn, Cd, Pb, Ni, and Cr. The application of WTS increased heavy-metal contents in the degraded soil. Although heavy metals were below their respective critical limits, sludge application onto degraded areas may cause hazardous environmental impact and thus must be monitored.

Solubilities of boric acid in heavy water

International Nuclear Information System (INIS)

Nakai, Shigetsugu; Aoi, Hideki; Hayashi, Ken-ichi; Katoh, Taizo; Watanabe, Takashi.

1988-01-01

A gravimetric analysis using meta-boric acid (HBO 2 or DBO 2 ) as a weighing form has been developed for solubility measurement. The method gave satisfactory results in preliminary measurement of solubilities of boric acid in light water. By using this method, the solubilities of 10 B enriched D 3 BO 3 in heavy water were measured. The results are as follows; 2.67 (7deg C), 3.52 (15deg C), 5.70 (30deg C), 8.87 (50deg C) and 12.92 (70deg C) w/o, respectively. These values are about 10% lower than those in light water. Thermodynamical consideration based on the data shows that boric acid is the water structure breaker. (author)

Pollution Status of Pakistan: A Retrospective Review on Heavy Metal Contamination of Water, Soil, and Vegetables

Directory of Open Access Journals (Sweden)

Amir Waseem

2014-01-01

Full Text Available Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water, soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health.

Natural uranium lattice in heavy water

International Nuclear Information System (INIS)

Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R.

1959-01-01

A group of Laplacian determinations have been made under critical running conditions in a heavy water pile specially constructed to this end using either complete lattices or samples of lattices employing a two-zone method. The experimental equipment is briefly described: it has been devised to allow rapid modifications of the charge. The methods of measurement employed are also summarily described one operates either by flux charts in the case of lattices which are then used as references, or by progressive replacement of the bars by concentric rings and measurements of the reactivity. In this case, one attempts to obtain the difference between the material laplacian of the central unknown lattice and that of the reference lattice. The method has been specially develop ped to give precision. Results of Laplacian measurements for all these lattice types are presented, allowing the construction of a set of curves as a function of the separation. Various other effects have also been measured: the equivalent reactivity of a mm of water - anisotropy - temperature effect, etc. However in this first attack on the problem, the measurement of a large variety of Laplacian has been carried out, rather than careful measurements in particular cases. It is in this spirit that the interpretation of the results has been made. As a large number of very complex phenomena still escape the possibilities of the calculation, it is considered that a certain number of adjustments are necessary; now these can only give the desired efficiency in forecasting results if they refer to a sufficiently great number of experimental data. It is necessary then to connect the measurements closely on with the other whilst, at the same time, subdividing them according to logically deduced formulae. The principal source of trouble has been that of coherence. The rules governing the calculations employed in the interpretation of the data are given. In the first instance simple formula are used: first of

Neutron moderation in heavy water

International Nuclear Information System (INIS)

Assis, J.T. de.

1980-03-01

The calculation of the energetic spectrum of thermic neutrons in heavy water, according to the models of the differential cross section; is presented. Simplifications in the Butler model are suggested for the diminution of computer time. The results obtained are compared with experimental data and with the Brown - St.John model. This calculation has been done in 30 energy groups and within our limit of precision, the results with the models and simplifications present satisfactory values, allowing its inclusion in reactor codes. (Author) [pt

Reactivity requirements and safety systems for heavy water reactors

International Nuclear Information System (INIS)

Kati, S.L.; Rustagi, R.S.

1977-01-01

The natural uranium fuelled pressurised heavy water reactors are currently being installed in India. In the design of nuclear reactors, adequate attention has to be given to the safety systems. In recent years, several design modifications having bearing on safety, in the reactor processes, protective and containment systems have been made. These have resulted either from new trends in safety and reliability standards or as a result of feed-back from operating reactors of this type. The significant areas of modifications that have been introduced in the design of Indian PHWR's are: sophisticated theoretical modelling of reactor accidents, reactivity control, two independent fast acting systems, full double containment and improved post-accident depressurisation and building clean-up. This paper brings out the evolution of design of safety systems for heavy water reactors. A short review of safety systems which have been used in different heavy water reactors, of varying sizes, has been made. In particular, the safety systems selected for the latest 235 MWe twin reactor unit station in Narora, in Northern India, have been discussed in detail. Research and Development efforts made in this connection are discussed. The experience of design and operation of the systems in Rajasthan and Kalpakkam reactors has also been outlined

Heavy-Water Power Reactors. Proceedings Of A Symposium

International Nuclear Information System (INIS)

1968-01-01

Proceedings of a Symposium organized by the IAEA and held in Vienna, 11-15 September 1967. The timeliness of the meeting was underlined by the large gathering of over 225 participants from 28 countries and three international organizations. Contents: Experience with heavy-water power and experimental reactors and projects (14 papers); New and advanced power reactor designs and concepts (8 papers); Development programmes and thorium cycle (9 papers); Economics and prospects of heavy-water power reactors (7 papers); Physics and fuel management (8 papers); Fuels (5 papers); Safety, control and engineering (6 papers); Panel discussion. Except for one Russian paper, which is published in English, each paper is in its original language (49 English and 8 French) and is preceded by an abstract in English with a second one in the original language if this is not English. Discussions are in English. (author)

Heavy-Water Power Reactors. Proceedings Of A Symposium

Energy Technology Data Exchange (ETDEWEB)

NONE

1968-04-15

Proceedings of a Symposium organized by the IAEA and held in Vienna, 11-15 September 1967. The timeliness of the meeting was underlined by the large gathering of over 225 participants from 28 countries and three international organizations. Contents: Experience with heavy-water power and experimental reactors and projects (14 papers); New and advanced power reactor designs and concepts (8 papers); Development programmes and thorium cycle (9 papers); Economics and prospects of heavy-water power reactors (7 papers); Physics and fuel management (8 papers); Fuels (5 papers); Safety, control and engineering (6 papers); Panel discussion. Except for one Russian paper, which is published in English, each paper is in its original language (49 English and 8 French) and is preceded by an abstract in English with a second one in the original language if this is not English. Discussions are in English. (author)

Decontamination and recycle of zirconium pressure tubes from Pressurized Heavy Water Reactor

International Nuclear Information System (INIS)

Gantayet, L.M.; Verma, R.; Remya Devi, P.S.; Banerjee, S.; Kotak, V.; Raha, A.; Sandeep, K.C.; Joshi, Shreeram W.; Lali, A.M.

2009-01-01

An ion exchange process has been developed for decontamination of zirconium pressure tubes from Pressurized Heavy Water Reactor and recycling of neutronically improved zirconium. Distribution coefficient, equilibrium isotherm, kinetic and breakthrough data were used to develop the separation process. Effect of gamma radiation on indigenous resins was also studied to assess their suitability in high radiation field. (author)

Heavy metals in water, sediments and submerged macrophytes in ponds around the Dianchi Lake, China.

Science.gov (United States)

Wang, Zhixiu; Yao, Lu; Liu, Guihua; Liu, Wenzhi

2014-09-01

Through retaining runoff and pollutants such as heavy metals from surrounding landscapes, ponds around a lake play an important role in mitigating the impacts of human activities on lake ecosystems. In order to determine the potential for heavy metal accumulation of submerged macrophytes, we investigated the concentrations of 10 heavy metals (i.e., As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in water, sediments, and submerged macrophytes collected from 37 ponds around the Dianchi Lake in China. Our results showed that both water and sediments of these ponds were polluted by Pb. Water and sediments heavy metal concentrations in ponds received urban and agricultural runoff were not significantly higher than those in ponds received forest runoff. This result indicates that a large portion of heavy metals in these ponds may originate from atmospheric deposition and weathering of background soils. Positive relationships were found among heavy metal concentrations in submerged macrophytes, probably due to the coaccumulation of heavy metals. For most heavy metals, no significant relationships were found between submerged macrophytes and their water and sediment environments. The maximum concentrations of Cr, Fe and Ni in Ceratophyllum demersum were 4242, 16,429 and 2662mgkg(-1), respectively. The result suggests that C. demersum is a good candidate species for removing heavy metals from polluted aquatic environments. Copyright © 2014 Elsevier Inc. All rights reserved.

A Management Strategy for the Heavy Water Reflector Cooling System of HANARO Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Jung, H. S.; Park, Y. C.; Lim, S. P. (and others)

2007-11-15

Heavy water is used as the reflector and the moderator of the HANARO research reactor. After over 10 years operation since first criticality in 1995 there arose some operational issues related with the tritium. A task force team(TFT) has been operated for 1 year since September 2006 to study and deduce resolutions of the issues concerning the tritium and the degradation of heavy water in the HANARO reflector system. The TFT drew many recommendations on the hardware upgrade, tritium containing air control, heavy water quality management, waste management, and tritium measurement system upgrade.

Effects of different cleaning treatments on heavy metal removal of Panax notoginseng (Burk) F. H. Chen.

Science.gov (United States)

Dahui, Liu; Na, Xu; Li, Wang; Xiuming, Cui; Lanping, Guo; Zhihui, Zhang; Jiajin, Wang; Ye, Yang

2014-01-01

The quality and safety of Panax notoginseng products has become a focus of concern in recent years. Contamination with heavy metals is one of the important factors as to P. notoginseng safety. Cleaning treatments can remove dust, soil, impurities or even heavy metals and pesticide residues on agricultural products. But effects of cleaning treatments on the heavy metal content of P. notoginseng roots have still not been studied. In order to elucidate this issue, the effects of five different cleaning treatments (CK, no treatment; T1, warm water (50°C) washing; T2, tap water (10°C) washing; T3, drying followed by polishing; and T4, drying followed by tap water (10°C) washing) on P. notoginseng roots' heavy metal (Cu, Pb, Cd, As and Hg) contents were studied. The results showed that heavy metal (all five) content in the three parts all followed the order of hair root > rhizome > root tuber under the same treatment. Heavy metal removals were in the order of Hg > As > Pb > Cu > Cd. Removal efficiencies of the four treatments were in the order of T2 > T1 > T3 > T4. Treatments (T1-T4) could decrease the contents of heavy metal in P. notoginseng root significantly. Compared with the requirements of WM/T2-2004, P. notoginseng roots' heavy metal contents of Cu, Pb, As and Hg were safe under treatments T1 and T2. In conclusion, the cleaning process after production was necessary and could reduce the content of heavy metals significantly. Fresh P. notoginseng root washed with warm water (T2) was the most efficient treatment to remove heavy metal and should be applied in production.

Accelerator driven heavy water blanket on circulating fuel

International Nuclear Information System (INIS)

Kazaritsky, V.D.; Blagovolin, P.P.; Mladov, V.R.; Okhlopkov, M.L.; Batyaev, V.F.; Stepanov, N.V.; Seliverstov, V.V.

1997-01-01

A conceptual design of a heavy water blanket with circulating fuel for an accelerator driven transmutation system is described. The hybrid system consists of a high-current linear accelerator of protons and 4 targets, each placed inside a subcritical blanket

Experimental study of heavy oil-water flow structure effects on relative permeabilities in a fracture filled with heavy oil

Energy Technology Data Exchange (ETDEWEB)

Shad, S.; Gates, I.D.; Maini, B.B. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering]|[Alberta Ingenuity Centre for In Situ Energy, Edmonton, AB (Canada)

2008-10-15

An experimental apparatus was used to investigate the flow of water in the presence of heavy oil within a smooth-walled fracture. Different flow patterns were investigated under a variety of flow conditions. Results of the experiments were used to determine the accuracy of VC, Corey, and Shad and Gates models designed to represent the behaviour of oil wet systems. The relative permeability concept was used to describe the behaviour of multiple phases flowing through porous media. A smooth-walled plexiglass Hele-Shaw cell was used to visualize oil and water flow. Changes in flow rates led to different flow regimes. The experiment demonstrated that water flowed co-currently in the form of droplets or slugs. Decreases in the oil flow rate enlarged the size of the water droplets as well as the velocity, until eventually the droplets coalesced and became water slugs. Droplet appearance or disappearance directly impacted the oil and water saturation levels. Changes in fluid saturation altered the pressure gradient. Darcy's law for the 2 liquid phases were used to calculate relative permeability curves. The study showed that at low water saturation, oil relative permeability reached as high as 2.5, while water relative permeability was lower than unity. In the presence of a continuous water channel, water drops formed in oil, and the velocity of the drops was lower than their velocity under a discontinuous water flow regime. It was concluded that the Shad and Gates model overestimated oil relative permeability and underestimated water relative permeability. 38 refs., 2 tabs., 9 figs.

Halden Boiling Water Reactor. Plant Performance and Heavy-Water Management

Energy Technology Data Exchange (ETDEWEB)

Aas, S.; Jamne, E.; Wullum, T.; Fjellestad, K. [Institutt for Atomenergi, OECD Halden Reactor Project, Halden (Norway)

1968-04-15

The Halden boiling heavy-water reactor, designed and built by the Norwegian Institutt for Atomenergi, has since June 1958 been operated as an international project. On its second charge the reactor was operated at power levels up to 25 MW and most of the time at a pressure of 28.5 kg/cm{sup 2}. During the period from July 1964 to December 1966 the plant availability was close to 64% including shutdowns because of test fuel failures and loading/unloading of fuel. Disregarding such stops, the availability was close to 90%. The average burnup of the core is about 6200 MWd/t UO{sub 2} : the most highly exposed elements have reached 10000 MWd/t UO{sub 2}. The transition temperature of the reactor tank has been followed closely. The results of the surveillance programme and the implication on the reactor operation are discussed. The reactor is located in a cave in a rock. Some experiences with such a containment are given. To locate failed test-fuel elements a fuel failure location system has been installed. A fission gas collection system has saved valuable reactor time during clean-up of the reactor system following test fuel failures. Apart from one incident with two of the control stations, the plant control and instrumentation systems have functioned satisfactorily. Two incidents with losses of 150 and 200 kg of heavy water have occurred. However, after improved methods for leakage detection had been developed, the losses have been kept better than 50 g/h . Since April 1962 the isotopic purity of the heavy water (14 t) has decreased from 99.75 to 99.62%. The tritium concentration is now slightly above 700 {mu}C/cm{sup 3}. This activity level has not created any serious operational or maintenance problems. An extensive series of water chemistry experiments has been performed to study the influence of various operating parameters on radiolytic gas formation. The main results of these experiments will be reported. Different materials such as mild steel, ferritic steel

Assessment of heavy metal concentration in water around the proposed Mkuju river uranium project in Tanzania

International Nuclear Information System (INIS)

Banzi, F.P.; Msaki, P.K.; Mohammed, N.K.

2015-01-01

Effective verification for compliance with water quality standards in uranium mining in Tanzania requires data sensitive to monitor heavy metal concentration in water around the Mkuju River Uranium Project before mining commences. The area susceptible for pollution by the project was estimated using AERMOD dispersion model and found to cover about 1300 km"2. Thirty one surface and groundwater samples were collected and analysed for heavy metals and physicochemical properties using ICP-MS and standards techniques, respectively. The physicochemical properties for water samples analysed ranges from 5.7 to 7.8 for pH, 2.8 to 80.2 mg/L for TDS and 15 to 534.5 mS/cm for EC. These values show that the water in the vicinity of the Mkuju River Uranium Project is normal. The ranges of concentration of heavy metals (µgL"-"1) determined in water ranges were: Al(2 to 9049), Cr(0.2 to 19.96), Mn (0.1 to 1452), Fe(2 to 53890), Co(0.02 to 27.63), Ni(0.2 to 9.7), Cu(2 to 17), Zn(2 to 62.94), As(0.4 to 19.17), Cd(0.02 to 0.14), Pb (0.02 to 78.68), Th (0.002 to 1.73), U(0.002 to 29.76). These values are below the tolerance levels of concentrations set by different International organisations. Therefore heavy metal toxicity in the study area is marginal. The parameters that could serve as baseline data because of their enhanced sensitivity to pollution were (i) concentration of chromium, cobalt, nickel, copper, zinc, arsenic, cadmium and lead in water (ii) pH, TDS and EC for water, (iii) TDS ratio for surface to ground water values and (iv) correlation coefficients between the heavy metals. However, since TDS values are season dependent, this indicator can serve as baseline data when measured during the dry season as was the case in the study. (author)

Advanced technology heavy water monitors offering reduced implementation costs

International Nuclear Information System (INIS)

Kalechstein, W.; Hippola, K.B.

1984-10-01

The development of second generation heavy water monitors for use at CANDU power stations and heavy water plants has been completed and the instruments brought to the stage of commercial availability. Applications of advanced technology and reduced utilization of custom manufactured components have together resulted in instruments that are less expensive to produce than the original monitors and do not require costly station services. The design has been tested on two prototypes and fully documented, including the inspection and test procedures required for manufacture to the CSA Z299.3 quality verfication program standard. Production of the new monitors by a commercial vendor (Barringer Research Ltd.) has begun and the first instrument is scheduled for delivery to CRNL's NRU reactor in late 1984

Concentration of Heavy Metals in Drinking Water from Urban Areas ...

African Journals Online (AJOL)

Bheema

drinking water treatment practices in the areas, which in turn have important human health implications. This study, therefore, recommends the government and other responsible authorities to take appropriate corrective measures. Key words: Drinking water quality, Heavy metals, Maximum admissible limit, World health.

Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

CERN Document Server

Dash, Monika

2013-01-01

Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

Heavy metal pollution in drinking water - a global risk for human ...

African Journals Online (AJOL)

Water resources in the world have been profoundly influenced over the last years by human activities, whereby the world is currently facing critical water supply and drinking water quality problems. In many parts of the world heavy metal (HM) concentrations in drinking water are higher than some international guideline ...

DEGRADATION EVALUATION OF HEAVY WATER DRUMS AND TANKS

Energy Technology Data Exchange (ETDEWEB)

Mickalonis, J.; Vormelker, P.

2009-07-31

Heavy water with varying chemistries is currently being stored in over 6700 drums in L- and K-areas and in seven tanks in L-, K-, and C-areas. A detailed evaluation of the potential degradation of the drums and tanks, specific to their design and service conditions, has been performed to support the demonstration of their integrity throughout the desired storage period. The 55-gallon drums are of several designs with Type 304 stainless steel as the material of construction. The tanks have capacities ranging from 8000 to 45600 gallons and are made of Type 304 stainless steel. The drums and tanks were designed and fabricated to national regulations, codes and standards per procurement specifications for the Savannah River Site. The drums have had approximately 25 leakage failures over their 50+ years of use with the last drum failure occurring in 2003. The tanks have experienced no leaks to date. The failures in the drums have occurred principally near the bottom weld, which attaches the bottom to the drum sidewall. Failures have occurred by pitting, crevice and stress corrosion cracking and are attributable, in part, to the presence of chloride ions in the heavy water. Probable degradation mechanisms for the continued storage of heavy water were evaluated that could lead to future failures in the drum or tanks. This evaluation will be used to support establishment of an inspection plan which will include susceptible locations, methods, and frequencies for the drums and tanks to avoid future leakage failures.

AECB staff annual report of Bruce Heavy Water Plant operation for the year 1991

International Nuclear Information System (INIS)

1992-11-01

Bruce Heavy Water Plant operation was acceptably safe in 1991. There were no breaches of any of the regulations issued under the authority of the Atomic Energy Control Act. There was one violation of the operating licence. For one hour on October 30, 1991, water leaving the plant contained more hydrogen sulphide than Ontario regulations allow. There was no threat to public health or safety or harm to the environment as a result of this violation. One worker was overcome by hydrogen sulphide. The worker did not lose consciousness, but had the symptoms of H 2 S poisoning. Ontario Hydro took actions to increase awareness of the Operating Policy and Principles at Bruce Heavy Water Plant during 1991. All personnel attended a training course, and Ontario Hydro is reviewing all Bruce Heavy Water Plant documentation to ensure it is consistent with the Operating Policies and Principles. Ontario Hydro met 13 of 15 safety-related system availability targets. The AECB is satisfied appropriate action is being taken to improve the performance of the other two systems. Ontario Hydro continued to put heavy emphasis on safety training; however, they did not meet some of their other training targets. Ontario Hydro completed all of the planned emergency exercises at Bruce Heavy Water Plant in 1991. (Author)

Significant Features of Warm Season Water Vapor Flux Related to Heavy Rainfall and Draught in Japan

Science.gov (United States)

Nishiyama, Koji; Iseri, Yoshihiko; Jinno, Kenji

2009-11-01

In this study, our objective is to reveal complicated relationships between spatial water vapor inflow patterns and heavy rainfall activities in Kyushu located in the western part of Japan, using the outcomes of pattern recognition of water vapor inflow, based on the Self-Organizing Map. Consequently, it could be confirmed that water vapor inflow patterns control the distribution and the frequency of heavy rainfall depending on the direction of their fluxes and the intensity of Precipitable water. Historically serious flood disasters in South Kyushu in 1993 were characterized by high frequency of the water vapor inflow patterns linking to heavy rainfall. On the other hand, severe draught in 1994 was characterized by inactive frontal activity that do not related to heavy rainfall.

Relativistic heavy-atom effects on heavy-atom nuclear shieldings

Science.gov (United States)

Lantto, Perttu; Romero, Rodolfo H.; Gómez, Sergio S.; Aucar, Gustavo A.; Vaara, Juha

2006-11-01

The principal relativistic heavy-atom effects on the nuclear magnetic resonance (NMR) shielding tensor of the heavy atom itself (HAHA effects) are calculated using ab initio methods at the level of the Breit-Pauli Hamiltonian. This is the first systematic study of the main HAHA effects on nuclear shielding and chemical shift by perturbational relativistic approach. The dependence of the HAHA effects on the chemical environment of the heavy atom is investigated for the closed-shell X2+, X4+, XH2, and XH3- (X =Si-Pb) as well as X3+, XH3, and XF3 (X =P-Bi) systems. Fully relativistic Dirac-Hartree-Fock calculations are carried out for comparison. It is necessary in the Breit-Pauli approach to include the second-order magnetic-field-dependent spin-orbit (SO) shielding contribution as it is the larger SO term in XH3-, XH3, and XF3, and is equally large in XH2 as the conventional, third-order field-independent spin-orbit contribution. Considering the chemical shift, the third-order SO mechanism contributes two-thirds of the difference of ˜1500ppm between BiH3 and BiF3. The second-order SO mechanism and the numerically largest relativistic effect, which arises from the cross-term contribution of the Fermi contact hyperfine interaction and the relativistically modified spin-Zeeman interaction (FC/SZ-KE), are isotropic and practically independent of electron correlation effects as well as the chemical environment of the heavy atom. The third-order SO terms depend on these factors and contribute both to heavy-atom shielding anisotropy and NMR chemical shifts. While a qualitative picture of heavy-atom chemical shifts is already obtained at the nonrelativistic level of theory, reliable shifts may be expected after including the third-order SO contributions only, especially when calculations are carried out at correlated level. The FC/SZ-KE contribution to shielding is almost completely produced in the s orbitals of the heavy atom, with values diminishing with the principal

Tritium separation from heavy water by electrolysis with solid polymer electrolyte

International Nuclear Information System (INIS)

Ogata, Y.; Ohtani, N.; Kotaka, M.

2003-01-01

A tritium separation from heavy water by electrolysis using a solid polymer electrode layer was specified. The cathode was made of stainless steel or nickel. The electrolysis was performed for 1 hour at 5, 10, 20, and 30 deg C. Using a palladium catalyst, generated hydrogen and oxygen gases were recombined, which was collected with a cold trap. The activities of the samples were measured by a liquid scintillation counter. The apparent tritium separation factors of the heavy and light water at 20 deg C were ∼2 and ∼12, respectively. (author)

Improvements done at Heavy Water Plant (Manuguru) to increase the standards of environmental protection

International Nuclear Information System (INIS)

Rama Rao, V.V.S.; Gupta, R.V.; Pandey, B.L.

1997-01-01

The Heavy Water Plant at Manuguru is designed to produce 185 MTY of nuclear grade heavy water based on bithermal H 2 S-H 2 O exchange process and handles large inventory of H 2 S gas (about 400 MT). As H 2 S gas is very toxic, corrosive and hazardous in nature, extreme care has been taken in the design of plant, selection of equipment and materials adhering to stringent fabrication procedures and codes to ensure the production of heavy water in a safe manner. This paper highlights the improvements done at Heavy Water Plant (Manuguru) to increase the standards of environmental protection. The safety assessment of a hazardous plant is a continuous process. Apart from the extreme care taken in the design, construction, commissioning and operation of the plant, review of each and every safety related unusual occurrence by various levels of review committees as stipulated and speedy implementation of the recommendations goes in a long way in increasing the standards of environmental protection

Physical and water properties of selected Polish heavy soils of various origins

Directory of Open Access Journals (Sweden)

Kaczmarek Zbigniew

2015-12-01

Full Text Available The paper presents the characteristics of selected physical, chemical, and water properties of four mineral arable soils characterized with heavy and very heavy texture. Soil samples from genetic horizons of black earths from areas near Kętrzyn, Gniew and Kujawy, and alluvial soils from Żuławy were used. The following properties were determined in the samples of undisturbed and disturbed structure: texture, particle density, bulk density, porosity, natural and hygroscopic moistures, maximal hygroscopic capacity, saturated hydraulic conductivity, potential of water bonding in soil, total and readily available water, total retention in the horizon of 0–50 cm, drainage porosity, content of organic carbon and total nitrogen Parent rocks of these soils were clays, silts and loams of various origin. High content of clay fraction strongly influenced the values of all the analyzed properties. All the examined soils had high content of organic carbon and total nitrogen and reaction close to neutral or alkaline. High content of mineral and organic colloids and, what follows, beneficial state of top horizons’ structure, determined – apart from heavy texture – low soil bulk density and high porosity. The investigated soils were characterized by high field water capacity and wide scopes of total and readily available water. The saturated hydraulic conductivity was low and characteristic to heavy mineral arable soils. The parameter which influenced the variability of analyzed parameters most was texture.

Health risks associated with heavy metals in the drinking water of Swat, northern Pakistan.

Science.gov (United States)

Lu, Yonglong; Khan, Hizbullah; Zakir, Shahida; Ihsanullah; Khan, Sardar; Khan, Akbar Ali; Wei, Luo; Wang, Tieyu

2013-10-01

The concentrations of heavy metals such as Cd, Cr, Cu, Mn, Ni, Pb and Zn were investigated in drinking water sources (surface and groundwater) collected from Swat valley, Khyber Pakhtunkhwa, Pakistan. The potential health risks of heavy metals to the local population and their possible source apportionment were also studied. Heavy metal concentrations were analysed using atomic absorption spectrometer and compared with permissible limits set by Pakistan Environmental Protection Agency and World Health Organization. The concentrations of Cd, Cr, Ni and Pb were higher than their respective permissible limits, while Cu, Mn and Zn concentrations were observed within their respective limits. Health risk indicators such as chronic daily intake (CDI) and health risk index (HRI) were calculated for adults and children separately. CDIs and HRIs of heavy metals were found in the order of Cr > Mn > Ni > Zn > Cd > Cu > Pb and Cd > Ni > Mn > Cr > Cu > Pb > Zn, respectively. HRIs of selected heavy metals in the drinking water were less than 1, indicating no health risk to the local people. Multivariate and univariate statistical analyses showed that geologic and anthropogenic activities were the possible sources of water contamination with heavy metals in the study area.

Development of backward equations T(p,h), T(p,s) and p(h,s) for heavy water liquid and vapor

International Nuclear Information System (INIS)

Nick P Petropoulos; Simos E Simopoulos

2005-01-01

Full text of publication follows: Backward equations for heavy water (a) temperature as a function of pressure and enthalpy T(p,h), (b) temperature as a function of pressure and entropy T(p,s) and (c) pressure as a function of enthalpy and entropy p(h,s) presented in this work, are based on the 'IAPS Formulation 1984 for the Thermodynamic Properties of Heavy Water Substance' [1], and also on the respective equations for the ordinary water substance as presented in 'The IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam' [2]. Heavy water and steam thermodynamic properties can be calculated using the basic equations and saturation equations that are included in [1]. However, [1] does not contain any backward functions T(p,h), T(p,s) and p(h,s), which are needed for heavy water thermodynamic process modeling. The development of the two temperature backward functions efficiently increases computational speed for temperature calculations more than three times as pointed out in the similar case problem for ordinary water, addressed successfully in [2]. Without these temperature backward functions calculations may be performed only iteratively using the heavy water state equations at a much greater computing cost. Moreover, the development of the pressure backward function saves even more computing time in modeling problems since two-dimensional iterations from the h(p,T) and s(p,T) heavy water functions may by effectively avoided. In addition, given the pressure function p(h,s), the heavy water temperature T(h,s) can be calculated by the temperature function T(p,h). The numerical consistencies of calculated T and p to the state equations included in [1] are sufficient for most applications in the heavy water nuclear reactors heat cycles. For applications, where the demands on numerical consistency and accuracy are rather high, iterations with the approved state equations may be necessary. In these cases both temperature and pressure

Long term assurance of supply of heavy water

International Nuclear Information System (INIS)

1978-01-01

The answer of Switzerland and Great Britain to a number of questions concerning the long-term assurance of the supply of heavy water are presented. The original problems are seen in the wider context of raw materials supply and its assurance in general. Non-proliferation aspects are touched

Visualization of viscous coupling effects in heavy oil reservoirs

Energy Technology Data Exchange (ETDEWEB)

Ortiz-Arango, J.D. [Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory; Kantzas, A. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory

2008-10-15

Some heavy oil reservoirs in Venezuela and Canada have shown higher than expected production rates attributed to the effects of foamy oil or enhanced solution gas drive. However, foamy oil 2-phase flow does not fully explain oil rate enhancement in heavy oil reservoirs. In this study, flow visualization experiments were conducted in a 2-D etched network micromodel in order to determine the effect of the viscosity ratio on oil mobility at the pore scale. The micromodel's pattern was characterized by macroscopic heterogeneities with a random network of larger pore bodies interconnected with a random network of smaller pore throats. Displacement tests were conducted with green-dyed distilled water as a wetting phase. N-octane, bromododecane and mineral oil were used as non-wetting phases. An unsteady-state method was used to obtain displacement data, and the Alternate method was used to calculate relative permeabilities. Results of the study showed that relative permeabilities depended on the viscosity ratio of the fluids flowing through the porous medium. Channel and annular flows co-existed, and water lubrication was stronger at higher water saturations. The results of the study explained the abnormally high production rates in heavier oil fields. 19 refs., 3 tabs., 14 figs.

On-line infrared heavy-water instruments: status, economics and prospects

International Nuclear Information System (INIS)

Lynch, G.F.

1978-06-01

An intensive program to rehabilitate and establish the reliability of on-line heavy-water monitors is now showing tangible results. After determining the operating specifications and characteristics of the infrared D 2 O analyzers manufactured by Barringer Research Limited, monitoring systems based on these instruments were installed and commissioned at reactors and heavy-water plants. Ten such systems are currently operating reliably in the field. Laboratory tests and field experience have identified design features which would make the analyzers more convenient to use and less sensitive to environmental conditions. The conceptual design of a new instrument which is less dependent on station services and more tolerant of plant conditions has been completed

CANDU - Canadian experience and expectations with the heavy-water reactor

International Nuclear Information System (INIS)

Foster, J.S.; Russell, S.H.

1977-05-01

The paper describes the evolution of the CANDU nuclear-power plants with particular reference to the objectives of safety, reliability and economy; the development of industrial capacity for the supply of fuel, components and heavy water; and the prospective development of advanced fuel cycles and the projected results. It provides data on radiation, releases, and exposures, internal and external to the power plants; plant availability, capacity factors and other performance data; heavy water production data with reference to safety, reliability, and economics; projections of the performance of CANDU reactors operating on a thorium-U-233 cycle and the development required to establish this cycle; and intent with respct to spent-fuel management and radioactive-waste storage. (author)

Benchmark testing of Canadol-2.1 for heavy water reactor

International Nuclear Information System (INIS)

Liu Ping

1999-01-01

The new version evaluated nuclear data library of ENDF-B 6.5 has been released recently. In order to compare the quality of evaluated nuclear data CENDL-2.1 with ENDF-B 6.5, it is necessary to do benchmarks testing for them. In this work, CENDL-2.1 and ENDF-B 6.5 were used to generated the WIMS-69 group library respectively, and benchmarks testing was done for the heavy water reactor, using WIMS5A code. It is obvious that data files of CENDL-2.1 is better than that of old WIMS library for the heavy water reactors calculations, and is in good agreement with those of ENDF-B 6.5

[Heavy metals in environmental media around drinking water conservation area of Shanghai].

Science.gov (United States)

Shi, Gui-Tao; Chen, Zhen-Lou; Zhang, Cui; Bi, Chun-Juan; Cheng, Chen; Teng, Ji-Yan; Shen, Jun; Wang, Dong-Qi; Xu, Shi-Yuan

2008-07-01

The levels of heavy metals in Shanghai drinking water conservation area were determined, and the spatial distributions and main sources of heavy metals were investigated. Moreover, the ecological risk assessment of heavy metals was conducted. Some conclusions can be drawn as follows: (1) The average concentrations of Cd, Hg, Pb, Cu, Zn, Ni, Cr and As in road dust were 0.80, 0.23, 148.45, 127.52, 380.57, 63.17, 250.38 and 10.37 mg x kg(-1) respectively. In terms of the pollution level, the values of soils were relatively lower, with the mean contents of 0.16 (Cd), 0.33 (Hg), 30.14 (Pb), 30.66 (Cu), 103.79 (Zn), 24.04 (Ni), 65.75 (Cr) and 6.31 mg x kg(-1) (As) severally; meanwhile the average levels of heavy metals in vegetables were 0.010 (Cd), 0.016 (Hg), 0.36 (Pb), 12.80 (Cu), 61.69 (Zn), 2.04 (Ni), 2.41 (Cr) and 0.039 mg x kg(-1) (As) respectively. (2) Semivariogram and multivariate analysis indicated that heavy metals pollution of soils was induced by anthropogenic activities mostly, and the pollutants produced by traffic were the major source of heavy metals in road dust. (3) The order for heavy metal enrichment coefficients of vegetables was as following: Zn (0.589) > Cu (0.412) > 0.102 (Ni) > Cd (0.059) > Cr (0.061) > Hg (0.056) > Pb (0.012) > As (0.007), and the results indicated that Cd and Zn in vegetables were mainly from the soils, and the other metals were probably from the pollutants in the atmosphere. (4) Sediments in drinking water conservation area were probably derived from soils around; however, there was no significant relationship between heavy metals contents of them. (5) The results of ecological risk assessment of heavy metals showed that heavy metals in soils were in no-warning to warning situation, and warning to light-warning situation for road dust and vegetables. The fuzzy synthesis judgment for all the environmental media around drinking water conservation area was warning to light-warning.

Growth scenarios with thorium fuel cycles in pressurised heavy water reactors

International Nuclear Information System (INIS)

Balakrishnan, M.R.

1991-01-01

Since India has generous deposits of thorium, the availability of thorium will not be a limiting factor in any growth scenario. It is fairly well accepted that the best system for utilisation of thorium is the heavy water reactor. The growth scenarios possible using thorium in HWRs are considered. The base has been taken as 50,000 tons of natural uranium and practically unlimited thorium. The reference reactor has been assumed to be the PHWR, and all other growth scenarios are compared with the growth scenario provided by the once-through natural cycle in the PHWR. Two reactor types have been considered: the heavy water moderated, heavy water cooled, pressure tube reactor, known as the PHWR; and the heavy water moderated and cooled pressure vessel kind, similar to the ATUCHA reactor in Argentina. For each reactor, a number of different fuel cycles have been studied. All these cycles have been based on thorium. These are: the self-sustaining equilibrium thorium cycle (SSET); the high conversion ratio high burnup cycle; and the once through thorium cycle (OTT). The cycle have been initiated in two ways: one is by starting the cycle with natural uranium, reprocessing the spent fuel to obtain plutonium, and use that plutonium to initiate the thorium cycle; the other is to enrich the uranium to about 2-3% U-235 (the so-called Low Enriched Uranium or LEU), and use the LEU to initiate the thorium cycle. Both cases have been studied, and growth scenarios have been projected for every one of the possible combinations. (author). 1 tab

Heavy metal contamination in stream water and sediments of gold ...

African Journals Online (AJOL)

This study assessed the seasonal variation in heavy metal contamination of stream water and sediments in the gold mining area of Atakunmosa West local Government, Osun State, Nigeria. Twelve villages of prominence in illegal gold mining were selected for the study covering dry and wet seasons of 2012. Stream water ...

The density behaviour of heavy oils in water

International Nuclear Information System (INIS)

Fingas, M.; Hollebone, B.; Fieldhouse, B.

2006-01-01

The recent concern regarding the difficulty of cleaning up Low API gravity oils (LAPIO) spilled in water was discussed. Sinking and overwashing are 2 phenomena related to the behaviour of these heavy oils in water. Sinking refers to the complete submergence of the oil to the bottom of a waterbody, while over-washing refers to the overflowing of a layer of water over dense oil at sea when the oil is still close to the surface. The latter is important because even a micron-layer of water could render the oil undetectable, particularly at acute viewing angles, such as from a ship. This paper reviewed the properties of heavy oil, the prediction of density changes and the sinking/over-washing of heavy oil. In particular, it discussed a spill which occurred in August 2005 when 11 tank cars from train derailment spilled 800,000 litres of Bunker fuel mixed with high PAH-containing pole-treating oil into Lake Wabamun, Alberta. The behaviour of the oil included submergence, neutral buoyancy, resurfacing and formation of several types of aggregates of oil. This study summarized the behaviours and processes that transformed the particles of oil into small tar balls, larger logs, sheets, and large lumps into a slick. Sediment uptake or loss was found to be the major process that caused the changes in density. The behaviour of the oils was compared with respect to density and uptake of various types of sediment. The paper also reviewed the literature on dense oil behaviour. Weathering experiments performed on dense oils to determine if extensive weathering could render oils heavier than water showed that rarely is weathering the only factor in the bulk sinking of oil. Once an oil is submerged, little weathering occurs, either by dissolution or volatilization. The uptake of particulate matter is the most important process in increasing density. This study reviewed over-washing experiments to develop a mathematical solution of the conditions required for oil to be covered by a

Effects of freshwater leaching on potential bioavailability of heavy metals in tidal flat soils.

Science.gov (United States)

Li, Hui; Lu, Jun; Li, Qu-Sheng; He, Bao-Yan; Mei, Xiu-Qin; Yu, Dan-Ping; Xu, Zhi-Min; Guo, Shi-Hong; Chen, Hui-Jun

2016-02-01

Leaching experiments were conducted to investigate the effects of desalination levels and sediment depths on potential bioavailability of heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in tidal flat soils. The data showed that both the desalination levels (p soil depths (p toxicity to benthic organisms than high desalination treatment. Since these reclaimed tidal flats with low desalinisation are suitable for saline water aquaculture, transforming the present land use of reclaimed tidal flats from fresh water aquaculture into saline water aquaculture may reduce health risk of heavy metals remained in sediments. These results will also contribute to our understanding of the dynamic behavior of heavy metals in the reclamation of tidal flats during leaching and the role of the ratio of SEM/AVS predictions on assessing the ecological risks of reclaimed tidal flats.

Neutron scattering of a floating heavy water bridge

International Nuclear Information System (INIS)

Fuchs, Elmar C; Bitschnau, Brigitte; Woisetschlaeger, Jakob; Maier, Eugen; Beuneu, Brigitte; Teixeira, Jose

2009-01-01

When high voltage is applied to distilled water filled into two beakers close to each other, a water connection forms spontaneously, giving the impression of a floating water bridge (Fuchs et al 2007 J. Phys. D: Appl. Phys. 40 6112-4, 2008 J. Phys. D: Appl. Phys. 41 185502). This phenomenon is of special interest, since it comprises a number of phenomena currently tackled in modern water science. In this work, the first data on neutron scattering of a floating heavy water bridge are presented and possible interpretations are discussed. D 2 O was measured instead of H 2 O because of the very strong incoherent scattering of H. The obtained data support the 'bubble hypothesis' suggested earlier (Fuchs et al 2008).

Water Quality in Surface Water: A Preliminary Assessment of Heavy Metal Contamination of the Mashavera River, Georgia

Science.gov (United States)

Urushadze, Teo

2018-01-01

Water quality contamination by heavy metal pollution has severe effects on public health. In the Mashavera River Basin, an important agricultural area for the national food system in Georgia (e.g., vegetable, dairy and wine production), water contamination has multiple influences on the regional and country-wide health. With new industrial activities in the region, sediment extraction, and discharge of untreated wastewater into the river, its tributaries and irrigation canals, a comprehensive study of water quality was greatly needed. This study examined sediment and water samples from 17 sampling sites in the Mashavera River Basin during the high and low precipitation seasons. The results were characterized utilizing the Geo-accumulation Index (Igeo), Enrichment Factor (EF), Pollution Load index (PLI), Contamination Factor (CF) and Metal Index (MI). According to the CFs, Cu > Cd > Zn > Pb > Fe > Mn > Ni > Cr > Hg is the descending order for the content of all observed heavy metals in sediments collected in both seasons. Fe and As were additionally examined in water samples. Overall, As, Cd and Pb, all highly toxic elements, were found in high concentrations in downstream sample sites. According to these results, comprehensive monitoring with narrow intervals between sampling dates, more sample sites along all waterways, and proximate observation of multiple trace metal elements are highly recommended. Moreover, as the part of the water quality governance system, an immediate and sustainable collective action by all stakeholders to control the pollution level is highly recommended, as this issue is linked to the security of the national food system and poses a local public health risk. PMID:29597320

Embalse nuclear power plant and heavy water valuation

International Nuclear Information System (INIS)

Martin, Daniel E.

2008-01-01

The author describes the nuclear power plant characteristics, the building work, the heavy water valuation criteria and the reasons why he considers that any capital good can be valued by the cash-flow method. The Embalse nuclear power plant replacement value is of U$S 1.593.538.000. (author) [es

Energy conservation measures adopted at Heavy Water Plant, Manuguru

International Nuclear Information System (INIS)

Gupta, R.V.; Venugopal, M.

1997-01-01

The importance of conservation of energy is well recognised all over the world as the world reserves of fossil fuels will eventually run out depending on the rate of their use. This paper deals with various energy conservation schemes adopted at Heavy Water Plant, Manuguru (HWPM). Most energy conservation measures offer large financial saving with very short pay back periods. This fact has been well recognised by the management of HWPM as well as Heavy Water Board and their wholehearted and enthusiastic approach to energy conservation and energy management yielded very good results in reducing the operating cost. The process of energy conservation is not a one time exercise. Persistent efforts are on to identify the areas like condition of heat exchangers, margins in control valves, steam and condensate leakages etc. for further reduction in energy consumption

A painless approach to use distributed digital-control system for Heavy Water Plant- Tuticorin

International Nuclear Information System (INIS)

Potti, V.S.; Krishnan, S.; Rao, V.C.; Lamba, D.S.

1994-01-01

Heavy Water Plant (Tuticorin) production is based on mono thermal process of ammonia-hydrogen exchange and is connected with a 1100 tons per day capacity ammonia plant of M/s Southern Petrochemical Industries Limited for getting its feed. The deuterium concentration in the syngas (N 2 + 3H 2 ) is extracted through ammonia-hydrogen exchange process and finally burnt with air in the final product unit to get heavy water. The depleted syngas is sent back to M/s SPIC's synthesis unit. The purpose of this paper is to highlight the instrumentation requirements of heavy water production, problems encountered in use of DDCS along with remedial action taken for the back up facility. (author)

Toenail as a biomarker of heavy metal exposure via drinking water: a systematic review.

Science.gov (United States)

Ab Razak, Nurul Hafiza; Praveena, Sarva Mangala; Hashim, Zailina

2015-01-01

Toenail is metabolic end product of the skin, which can provide information about heavy metal accumulation in human cells. Slow growth rates of toenail can represent heavy metal exposure from 2 to 12 months before the clipping. The toenail is a non-invasive biomarker that is easy to collect and store and is stable over time. In this systematic review, the suitability of toenail as a long-term biomarker was reviewed, along with the analysis and validation of toenail and confounders to heavy metal. This systematic review has included 30 articles chosen from a total of 132 articles searched from online electronic databases like Pubmed, Proquest, Science Direct, and SCOPUS. Keywords used in the search included "toenail", "biomarker", "heavy metal", and "drinking water". Heavy metal in toenail can be accurately analyzed using an ICP-MS instrument. The validation of toenail heavy metal concentration data is very crucial; however, the Certified Reference Material (CRM) for toenail is still unavailable. Usually, CRM for hair is used in toenail studies. Confounders that have major effects on heavy metal accumulation in toenail are dietary intake of food and supplement, smoking habit, and overall health condition. This review has identified the advantages and limitations of using toenail as a biomarker for long-term exposure, which can help future researchers design a study on heavy metal exposure using toenail.

Red cabbage yield, heavy metal content, water use and soil chemical characteristics under wastewater irrigation.

Science.gov (United States)

Tunc, Talip; Sahin, Ustun

2016-04-01

The objective of this 2-year field study was to evaluate the effects of drip irrigation with urban wastewaters reclaimed using primary (filtration) and secondary (filtration and aeration) processes on red cabbage growth and fresh yield, heavy metal content, water use and efficiency and soil chemical properties. Filtered wastewater (WW1), filtered and aerated wastewater (WW2), freshwater and filtered wastewater mix (1:1 by volume) (WW3) and freshwater (FW) were investigated as irrigation water treatments. Crop evapotranspiration decreased significantly, while water use efficiency increased under wastewater treatments compared to FW. WW1 treatment had the lowest value (474.2 mm), while FW treatments had the highest value (556.7 mm). The highest water use efficiency was found in the WW1 treatment as 8.41 kg m(-3), and there was a twofold increase with regard to the FW. Wastewater irrigation increased soil fertility and therefore red cabbage yield. WW2 treatment produced the highest total fresh yield (40.02 Mg ha(-1)). However, wastewater irrigation increased the heavy metal content in crops and soil. Cd content in red cabbage heads was above the safe limit, and WW1 treatment had the highest value (0.168 mg kg(-1)). WW3 treatment among wastewater treatments is less risky in terms of soil and crop heavy metal pollution and faecal coliform contamination. Therefore, WW3 wastewater irrigation for red cabbage could be recommended for higher yield and water efficiency with regard to freshwater irrigation.

Use of polarography for comparative assussment of water quality with respect to heavy metals

International Nuclear Information System (INIS)

Osyka, V.F.; Khejfets, L.Ya.; Maksimovskij, S.G.; Kabanenko, L.F.

1994-01-01

Behaviour and mutual influence of heavy metal ions in river waters were investigated. It was found that in the presence of Cr 3+ binding of Cu 2+ , Cd 2+ , Pb 2+ , Zn 2+ , Ni 2+ , Co 2+ , Mn 2+ ions in complexes accelerated markedly and became dependent on metal addition sequence and time interval between their addition. This effect may be used for comparative assessment of water quality and prediction of the possibility of their detoxication

Effect of design and operation of modern ammonia plants on the performance of integrated heavy water plants (Paper No. 2.1)

International Nuclear Information System (INIS)

Kumar, Manoj; Haldar, T.K.; Gupta, S.K.; Ramamurty, C.B.

1992-01-01

The heavy water plant being parasitic in nature, its design, operation and performance is affected to a great extent by the design, performance and operation of the ammonia plant. Some of the factors which affect the performance of heavy water plant such as on-stream hours and capacity utilisation of the ammonia plant, deuterium concentration (D/D+H) in feed synthesis gas, operating pressure of synthesis loop of ammonia plant, composition of feed synthesis gas, and level of oxygenated impurities in feed synthesis gas are described in this paper. (author). 3 tabs., 4 figs

Effects of heavy water on ultrastructural and functional status of Hep 2 and CHO cells lysosomes

International Nuclear Information System (INIS)

Buzgariu, Wanda; Caloianu, Maria; Zarnescu, Otilia; Cimpean, Anisoara; Titescu, Gh.; Stefanescu, I.

2002-01-01

The heavy water effects on the ultrastructure and function of Hep 2 and CHO lysosomal cell compartment were investigated using electron microscopy and enzymatic studies. The cell viability, measured by neutral red uptake assay, and the total protein content determination, have shown a dose dependent decrease in cell growth for both studied cell types. The electron microscopy study has revealed a progressive increase in number and size of lysosomes and autophagosomes after 96 h exposure to different deuterium concentration media in a dose dependent manner. The enzymatic determination in the lysosomal pellet revealed an increased acid phosphatase activity in both cell types (15% and 33% for Hep 2 and 24% and 52% for CHO, respectively) exposed to media with high (65%, 90%) D 2 O content. (authors)

D2O, Computation of Thermodynamic and Transport Properties of Heavy Water

International Nuclear Information System (INIS)

Durmayaz, Ahmet

2000-01-01

1 - Description of program or function: A computer program for the fast computation of the thermodynamic and transport properties of heavy water (D 2 O) at saturation, in subcooled liquid and superheated vapor states. Specific volume (or density), specific enthalpy, specific entropy, constant-pressure specific heat and temperature at saturation are calculated by a number of piecewise continuous approximation functions of (and their derivatives are calculated with respect to) pressure whereas pressure at saturation is calculated by a piecewise continuous approximation function of temperature for heavy water. Density in subcooled liquid state, specific volume in super-heated vapor state, specific enthalpy, specific entropy and constant-pressure specific heat in both of these states are calculated by some piecewise continuous approximation functions of pressure and temperature for heavy water. The correlations used in the calculation of these thermodynamic properties of heavy water were derived by fitting some appropriate curves to the data given in the steam tables by Hill et al (1981). The whole set of correlations and the approximation method used in their derivation are presented by Durmayaz (1997). Dynamic viscosity and thermal conductivity for heavy water are calculated as functions of temperature and density with the correlations given by Hill et al (1981), by Matsunaga and Nagashima (1983) and by Kestin et al (1984). Surface tension for heavy water is calculated as a function of temperature with the correlation given by Crabtree and Siman-Tov (1993). 2 - Methods: A group of pressure-enthalpy (P-h) pairs can be given in an input data file or assigned in the main program without knowing the state in which fluid takes place. In this case, first, the enthalpies at saturation corresponding to the given pressure are computed. Second, the state is determined by comparing the given enthalpy to the saturation enthalpies. Then, the properties are computed. Program D 2 O

Device and method to enrich and process heavy water

International Nuclear Information System (INIS)

Hammerli, M.M.; Butler, J.P.

1979-01-01

A device to process and enrich heavy water is proposed which is based on a combined electrolysis catalyst exchange system in which a D 2 O enrichment of more than 99.8% is achieved in the end stage. Water partly enriched with D 2 -containing hydrogen gas from an electrolysis cell is brought into contact in a catalyst column. The water is further enriched here with deuterium. It is then fed to the electrolysis cell. Details of the apparatus are closely described. (UWI) [de

Waste minimization through process optimization/integration and resource management at eco-friendly Heavy Water Plants

International Nuclear Information System (INIS)

Nageshri, Jagdish; Gupta, S.K.

2004-01-01

Heavy Water Board has celebrated 2003 as Environmental Conservation Year captivating a range of enviro-friendly measures. This article attempts to give a brief overview of the outcome of systems and adapted procedures for waste minimization through process integration and resource management at Heavy Water Plants

Advances in heavy water reactors

International Nuclear Information System (INIS)

1994-03-01

The current IAEA programme in advanced nuclear power technology promotes technical information exchange between Member States with major development programmes. The Technical Committee Meeting (TCM) on Advances in Heavy Water Reactors was organized by the IAEA in the framework of the activities of the International Working Group on Advanced Technologies for Water Cooled Reactors (IWGATWR) and hosted by the Atomic Energy of Canada Limited. Sixty-five participants from nine countries (Canada, Czech Republic, India, German, Japan, Republic of Korea, Pakistan, Romania and USA) and the IAEA attended the TCM. Thirty-four papers were presented and discussed in five sessions. A separate abstract was prepared for each of these papers. All recommendations which were addressed by the participants of the Technical Committee meeting to the IWGATWR have been submitted to the 5th IWGATWR meeting in September 1993. They were reviewed and used as input for the preparation of the IAEA programme in the area of advanced water cooled reactors. This TCM was mainly oriented towards advances in HWRs and on projects which are now in the design process and under discussion. Refs, figs and tabs

Poultry litter-based activated carbon for removing heavy metal ions in water.

Science.gov (United States)

Guo, Mingxin; Qiu, Guannan; Song, Weiping

2010-02-01

Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

Heavy metal contamination of water and fish in peri-urban dams ...

African Journals Online (AJOL)

Heavy metals were measured in water, sediment and fish in dams located downstream of effluent discharge zones in Bulawayo and were compared to those in a pristine upstream dam. Water conductivity indicated pollution of downstream dams. Levels of lead (0.13 – 0.28 ppm) and cadmium (0.02 – 0.06 ppm) in water from ...

Heavy water production benefits of a supporting r and d program

International Nuclear Information System (INIS)

Bancroft, A.R.; Chuang, K.T.; Dalrymple, D.G.

1981-01-01

Considerable economic benefit was obtained from an active R and D program while the Canadian heavy water plants were brought to mature operation during the 1970s. The introduction to Canada of this new chemical processing industry led to unexpected process, equipment and materials problems. Having a small team of technical experts already working on heavy water processes and a much larger R and D team working in related fields allowed a rapid response to the problems that limited production. The number of engineers and scientists working on the GS process rose rapidly from a skeleton team in 1970 to 54 during 1974. Effort declined steadily as the major problems were solved and reached 22 by 1980. Cumulative effort over the decade was 264 man-years at a cost of 3.3 percent of the value of the heavy water produced. The new production benefits have lagged behind the R and D expenditure by a few years and the current spending rate is 1.2 percent of product value. Important contributions were made in the areas of process simulation, process chemistry, materials of construction, sieve trays, and mechanical equipment

Heavy metal pollution in drinking water - a global risk for the human ...

African Journals Online (AJOL)

Fabian Fernandez

parts of the world heavy metal (HM) concentrations in drinking water are higher than some international guideline values. ..... become the basis for several drinking water treatment approaches ...... physiological and hygienic needs. Monitoring ...

Various analytical techniques used for the measurement of isotopic purity of heavy water at Madras Atomic Power Station

International Nuclear Information System (INIS)

Satyanarayanan, V.; Umapathy, P.; Bhaskaran, R.; Nagarajan, J.; Pradeep, Jeena; Ayyar, S.R.

2008-01-01

The paper deals with the various techniques used for the measurement of isotopic purity of heavy water samples received from different sources viz. reactor systems, heavy water upgrading plant and fresh consignment from heavy water production plants. Heavy water is used in PHWRs as moderator and primary coolant. Isotopic Purity is an important parameter to be monitored/analysed regularly for both the systems. There is a minimum isotopic purity level to be maintained in the moderator system due to neutron economy/fuel burnup and in the case of coolant system the measurement is of paramount importance due to its safety considerations. The selection of the method of analysis depends on the isotopic range. The techniques used to measure the isotopic purity of heavy water are a) Infrared Spectrophotometry b) Refractometry c) Densitometry. Infrared spectrometer uses the property of molecular absorption of IR radiation by HOD species and the absorbance is the measure of isotopic purity. This technique is generally used for measuring high isotopic (80-99.98%) and low isotopic samples. Refractometer uses the property of refractive index of heavy water. The difference in refractive indices of light water and heavy water is 0.0048. A 1 % change in D 2 O concentration would thus equal to 0.000048 refractive index units. This method is used for determining the approximate isotopic value of a sample. Density meter uses the property of difference in densities of light and heavy water. The difference in density of 99.999% D 2 O and light water is 0.107540 which covers the whole range of interest. The experience gained with these techniques in the measurements of isotopic purity of various samples are presented in this paper. (author)

Water Quality and Heavy Metal Concentrations in Sediment of Sungai Kelantan, Kelantan, Malaysia: A Baseline Study

International Nuclear Information System (INIS)

Ahmad, A.K.; Mushrifah, I.; Mohamad Shuhaimi Othman

2009-01-01

A study on water quality and heavy metal concentration in sediment at selected sites of Sungai Kelantan was carried out. Ten water samples were collected along the river for physical and chemical analysis and twenty-six water and sediment samples were collected for heavy metal analysis. Water was sampled at three different dates throughout the study period whereas sediments were collected once. In addition to heavy metal analysis, sediment samples were also analysed for texture, ph and organic content. The physical and chemical water quality analyses were carried out according to the ALPHA procedures. Result of water quality analysis (physico-chemical) indicated that Sungai Kelantan is characterised by excellent water quality and comparable to pristine ecosystems such as the National Park and Kenyir Lake. This river was classified into class I - class III based on Malaysian interim water quality standard criteria (INWQS). Heavy metals Pb, Zn, Cu and Cd was detected at low concentration in sediment samples, except for Fe and Mn. The presence of Fe and Mn in sediment samples was though to be of natural origin from the soil. Anthropogenic metal concentrations in sediment were low indicating that Sungai Kelantan has not experienced extreme pollution. (author)

A painless approach to use distributed digital-control system for Heavy Water Plant- Tuticorin

Energy Technology Data Exchange (ETDEWEB)

Potti, V S; Krishnan, S; Rao, V C; Lamba, D S [Heavy Water Project, Tuticorin (India)

1994-06-01

Heavy Water Plant (Tuticorin) production is based on mono thermal process of ammonia-hydrogen exchange and is connected with a 1100 tons per day capacity ammonia plant of M/s Southern Petrochemical Industries Limited for getting its feed. The deuterium concentration in the syngas (N{sub 2} + 3H{sub 2}) is extracted through ammonia-hydrogen exchange process and finally burnt with air in the final product unit to get heavy water. The depleted syngas is sent back to M/s SPIC`s synthesis unit. The purpose of this paper is to highlight the instrumentation requirements of heavy water production, problems encountered in use of DDCS along with remedial action taken for the back up facility. (author). 3 refs., 2 figs.

Heavy metals, PAHs and toxicity in stormwater wet detention ponds

DEFF Research Database (Denmark)

Wium-Andersen, Tove; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild

2011-01-01

Concentrations of 6 different heavy metals and total Polycyclic Aromatic Hydrocarbons (PAH) were determined in stormwater runoff and in the pond water of two Danish wet detention ponds. The pond water samples were analyzed for toxic effects, using the algae Selenastrum capricornutum as a test...... organism. Stormwater and pond water from a catchment with light industry showed high levels of heavy metals, especially zinc and copper. The pond water showed high toxic effects and copper were found to be the main toxicant. Additionally, a large part of the copper was suspected to be complex bound......, reducing the potential toxicity of the metal. Another catchment (residential) produced stormwater and pond water with moderate concentration of heavy metals. The pond water occasionally showed toxic effects but no correlation between heavy metals and toxicity was identified. PAHs concentrations were...

Process development, design and operation of off-line purification system for oil-contaminated impure heavy water

International Nuclear Information System (INIS)

Bose, H.; Rakesh Kumar; Gandhi, H.C.; Unny, V.K.P.; Ghosh, S.K.; Mishra, Vivek; Shukla, D.K.; Duraisamy, S.; Agarwal, S.K.

2004-01-01

A large volume of degraded, tritiated heavy water contaminated with mineral oil and ionic impurities have accumulated at Dhruva in the past years of reactor operation as a result of routine operation and maintenance activities. The need was felt for a simple and efficient process that could be set up and operated locally at site using readily available materials, to purify the accumulated impure heavy waters at Dhruva so as to make them acceptable at the up gradation facilities. After a detailed laboratory study, a three stage clean-up process was developed which could purify a highly turbid oil-water emulsion to yield clear, oil-free and de-mineralized heavy water at reasonable rates of volume through-put. Based on the laboratory data, a suitably scaled up purification unit has been designed and commissioned which in the past few months has processed a sizeable volume of oil-contaminated heavy water waste from Dhruva, with most satisfactory results

Investigations for heavy metals pollution in the Nile water in Khartoum area using XRF

International Nuclear Information System (INIS)

Salih, Saadia Elsir

1998-06-01

The purpose of this study was to perform measurements for heavy metals pollution in the Nile water in Khartoum area. Ten locations were selected for the study on the white Nile, the Blue Nile and the Nile. Standard methods were used for samples collection and preparation for the measurements using XRF. Nine elements were observed and their concentrations determined in the various locations. These Ti, Cr, Fe, Cu, Zn, As, Pb, Zr, and Se. From the performed measurements for heavy metals pollution in the Nile water in Khartoum area using the XRF method the following conclusions can be made: There is no heavy metal pollution in the Nile water in Khartoum area resulting from industrial activities. However, there are indications for possible Pb pollution resulting from automobile emission. - The concentrations for the observed heavy metals, except Fe, were much below the maximum permissible international levels provided by the USA, EEC and WHO. - The origin for the observed concentrations of heavy metals, except for Pb, was considered to be soil and silt carried by river in it's journey from the Ethiopian Highlands and lake Victoria. (Author)

Safety and environmental aspects of heavy water production (Paper No. 4.1)

International Nuclear Information System (INIS)

Singh, Mohinder

1992-01-01

Different processes are utilised for heavy water production in the heavy water plants in India. H 2 S is used in large quantities as carrier gas to extract deuterium content from water. The safe handling of such large quantities of H 2 S gas poses a major problem because of its toxicity, high corrosive nature and high flammability. Handling of large quantities of synthesis gas in ammonia based plants at high pressure and temperature poses a major problem because it is a mixture of hydrogen and nitrogen. H 2 is highly inflammable and explosive when mixed with air or oxygen. All the safety aspects considered while designing, fabricating, constructing and operating the plants are described. (author). 5 tabs

Heavy water jet target and a beryllium target for production of fast neutrons

International Nuclear Information System (INIS)

Logan, C.M.; Anderson, J.D.; Barschall, H.H.; Davis, J.C.

1975-01-01

A limitation on the neutron flux obtainable from proton or deuteron induced reactions is the heating of the target by the accelerated charged particles. The heat can be removed more easily if the target moves. The possibility of using a rotating Be target and a heavy water jet as a target for bombardment by 35-MeV deuterons was studied. In a thick Be metal target moving at 10 m/sec through such a beam of 1 cm diameter a temperature pulse of about 300 0 C will be produced by the 0.3 MW beam. The Be target should be able to withstand such a temperature pulse. A Be target suitable for 3 MW of power in a 1 cm diameter beam would require internal cooling and a higher velocity. A free jet of heavy water is also a possible target. Laser photographs of water jets in vacuum show small angles of divergence. The effect of heating by a 0.3 MW beam is probably not important because the temperature rise produced by the beam is small compared to the absolute temperature of the unheated jet. (auth)

Bioaccumulation of heavy metals in organs of fresh water fish Cyprinus carpio (Common carp)

International Nuclear Information System (INIS)

Vinodhini, R.; Narayanan, M.

2008-01-01

The objective of the present study is to determine the bioaccumulation of heavy metals in various organs of the fresh water fish exposed to heavy metal contaminated water system. The experimental fish was exposed to Cr. Ni, Cd and Pb at sublethal concentrations for periods of 32 days. The elements Cd, Pb, Ni and Cr were assayed using Shimadzu AA 6200 atomic absorption spectrophotometry and the results were given as μg/g dry wt. The accumulation of heavy metal gradually increases in liver during the heavy metal exposure period. All the results were statistically significant at p Pb > Ni > Cr and Pb > Cd > Ni > Cr. Similarly, in case of kidney and flesh tissues, the order was Pb > Cd > Cr > Ni and Pb > Cr > Cd > Ni. In all heavy metals, the bioaccumulation of lead and cadmium proportion was significantly increased in the tissues of Cyprinus carpio (Common carp)

Measurement of M{sup 3} and k{sub {infinity}} for heavy water natural uranium assembly

Energy Technology Data Exchange (ETDEWEB)

Popovic, D; Raisic, N; Markovic, H; Takac, S; Zdravkovic, Z; Lolic, B [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)

1959-03-15

The migration length M and the infinite multiplication factor k{sub {infinity}} of the heavy water-natural uranium bare assembly are determined by measuring the reactivity of the reactor as function of the heavy water level. Since the assembly is non reflected the results obtained are of relatively high accuracy. (author)

Heavy water. An original project in the Argentine Patagonia

International Nuclear Information System (INIS)

Conde Bidabehere, Luis F.

2000-01-01

The history of the heavy water production plant built in Arroyito, in the Argentine province of Neuquen is related. Details are given on the development of the project and on the operation of the plant. The possible complementary production of ammonia and fertilizers is analyzed

Health risk assessment of heavy metals and metalloid in drinking water from communities near gold mines in Tarkwa, Ghana.

Science.gov (United States)

Bortey-Sam, Nesta; Nakayama, Shouta M M; Ikenaka, Yoshinori; Akoto, Osei; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-07-01

Concentrations of heavy metals and metalloid in borehole drinking water from 18 communities in Tarkwa, Ghana, were measured to assess the health risk associated with its consumption. Mean concentrations of heavy metals (μg/L) exceeded recommended values in some communities. If we take into consideration the additive effect of heavy metals and metalloid, then oral hazard index (HI) results raise concerns about the noncarcinogenic adverse health effects of drinking groundwater in Huniso. According to the US Environmental Protection Agency's (USEPA) guidelines, HI values indicating noncarcinogenic health risk for adults and children in Huniso were 0.781 (low risk) and 1.08 (medium risk), respectively. The cancer risk due to cadmium (Cd) exposure in adults and children in the sampled communities was very low. However, the average risk values of arsenic (As) for adults and children through drinking borehole water in the communities indicated medium cancer risk, but high cancer risk in some communities such as Samahu and Mile 7. Based on the USEPA assessment, the average cancer risk values of As for adults (3.65E-05) and children (5.08E-05) indicated three (adults) and five (children) cases of neoplasm in a hundred thousand inhabitants. The results of this study showed that residents in Tarkwa who use and drink water from boreholes could be at serious risk from exposure to these heavy metals and metalloid.

Standards for deuterium analysis requirements of heavy water plants (Preprint No. CA-1)

Energy Technology Data Exchange (ETDEWEB)

Rathi, B N; Gopalakrishnan, V T; Alphonse, K P; Pawar, P L; Sadhukhan, H K [Bhabha Atomic Research Centre, Bombay (India). Heavy Water Div.

1989-04-01

Accurate analysis of deuterium, covering the entire range, is of great importance in production of heavy water. Most of the methods for determination of deuterium in gas or liquid samples require appropriate standards. Since density of pure protium oxide and pure deuterium oxide has been determined very accurately by a large number of workers and density of mixtures of H{sub 2}O and D{sub 2}O follows a linear relation, it is possible to use accurate density determination for measurement of deuterium content. Float method for density measurements was improved further and used for the preparation of primary heavy water standards in high and low deuterium ranges. Heavy water plant laboratories require gas standards (ammonia synthesis gas matrix), in addition to low deuterium water standards, for calibration of mass spectrometers. SLAP (Standard Light Antarctic Precipitation, D/D+H = 89.02+-0.05ppm) and SMOW (Standard Mean Ocean Water, D/D+H =155.76+-0.05ppm) available from IAEA, Vienna, along with water practically free from deuterium, were used as standards to prepare secondary liquid standards. These secondary standards were subsequently reduced and mixed with pure nitrogen to obtain D/D+H standards in syngas matrix. (author). 8 refs., 2 figs.

Radiation dose due to radon and heavy metal analysis in drinking water samples of Jammu District, Jammu and Kashmir, India

International Nuclear Information System (INIS)

Kumar, A.; Kaur, M.; Sharma, S.; Mehra, R.; Sharma, D.K.; Mishra, R.

2016-01-01

In the present investigation, radon concentration and heavy metal analysis were carried out in drinking water samples in Jammu district, Jammu and Kashmir, India. The radon concentration was measured by using RAD-7, portable alpha particle detector. The values of radon concentration in drinking water samples were also compared within the safe limit recommended by different health agencies. The total annual effective dose ranged from 53.04 to 197.29 μSv y -1 . The annual effective dose from few locations from the studied area was found to be greater than the safe limit (100 μSv y -1 ) suggested by World Health Organisation (WHO) and EU Council. Heavy metal concentration was determined by atomic absorption spectrophotometer. A total of eight elements were analysed, viz. arsenic, mercury, zinc, iron, copper, chromium, manganese and cadmium. Heavy metals are considered to be the major pollutants of water sources. The results were compared with the limits of WHO, EU and Indian organisations. The trace metal analysis is not on the exceeding side of the permissible limit in all the samples. (authors)

Determination of heavy metals and genotoxicity of water from an ...

African Journals Online (AJOL)

Determination of heavy metals and genotoxicity of water from an artesian well ... do Amaral, Vanessa Marques de Oliveira Moraes, Luciana Pereira Silva ... environmental interest because it is the most important zinc producer district of Brazil.

Monitoring of heavy metals in selected Water Supply Systems in Poland, in relation to current regulations

Science.gov (United States)

Szuster-Janiaczyk, Agnieszka; Zeuschner, Piotr; Noga, Paweł; Skrzypczak, Marta

2018-02-01

The study presents an analysis of water quality monitoring in terms of the content of heavy metals, which is conducted in three independent water supply systems in Poland. The analysis showed that the monitoring of heavy metals isn't reliable - both the quantity of tested water samples and the location of the monitoring points are the problem. The analysis of changes in water quality from raw water to tap water was possible only for one of the analysed systems and indicate a gradual deterioration of water quality, although still within acceptable limits of legal regulations.

Selective heavy metals removal from waters by amorphous zirconium phosphate: behavior and mechanism.

Science.gov (United States)

Pan, Bingcai; Zhang, Qingrui; Du, Wei; Zhang, Weiming; Pan, Bingjun; Zhang, Qingjian; Xu, Zhengwen; Zhang, Quanxing

2007-07-01

Selective removal of heavy metals from water has been of considerable concern for several decades. In the present study, the amorphous zirconium phosphate (ZrP) was synthesized and characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron micrography (SEM), thermogravimetric analysis (TGA) as well as pH-titration experiments. Uptake of heavy metals including lead, cadmium, and zinc onto ZrP was studied by using a polystyrene sulfonic-acid exchanger D-001 as a reference sorbent and Ca(2+) as a competing cation due to its ubiquity in natural or industrial waters. The results indicated that the uptake of heavy metals onto ZrP is essentially an ion-exchange process and dependent upon solution pH. In comparison with D-001, ZrP exhibited more favorable sorption of heavy metals particularly in terms of high selectivity, as indicated by the distribution coefficients of ZrP even several orders higher than D-001 towards heavy metals when calcium ion coexisted at a high level in solution. The Fourier transform-infrared (FT-IR) spectroscopic investigation indicated that the uptake of calcium, cadmium, and zinc ions onto ZrP is only driven by the electrostatic interaction, while that of lead ion is possibly dependent upon the inner-sphere complex formation with ZrP. XPS results further elucidated that ZrP displays different sorption affinity towards heavy metals in the same order as selectivity sequence of Pb(2+)>Zn(2+) approximately Cd(2+)>Ca(2+), which can be explained by hard and soft acids and bases (HASB) theory. Moreover, uptake of heavy metals onto ZrP approached to equilibrium quickly and the used ZrP could be readily regenerated for reuse by the dilute HCl solution. Thus, all the results suggest that amorphous ZrP has excellent potential as a sorption material for water treatment.

Combined electrolysis and catalytic exchange (CECE) technology - an economical alternative for heavy water upgraders using water distillation

International Nuclear Information System (INIS)

Ryland, D.K.; Sadhankar, R.R.

2003-01-01

Heavy water upgrading is a unique and crucial part of a CANDU power station. Water distillation (DW) systems are used for heavy water upgrading in all CANDU stations. The DW upgrader is designed to take advantage of the difference in relative volatility (a measure of separation of isotopes) between H 2 O and D 2 O. However, the low relative volatility of the H 2 O/D 2 O system requires large number of stages (long columns) and large reflux ratios (large reboiler loads) - thus resulting in significant capital and operating costs. Atomic Energy of Canada Limited (AECL) developed the Combined Electrolysis and Catalytic Exchange (CECE) technology as an economical alternative to the DW system. CECE-based upgraders have been demonstrated in pilot scale facilities at AECL Chalk River Laboratories and in Hamilton, Ontario. This design is based on catalytic hydrogen isotope exchange between water and hydrogen gas. (author)

Consequence of potential accidents in heavy water plants

International Nuclear Information System (INIS)

Croitoru, C.; Lazar, R.E.; Preda, I.A.; Dumitrescu, M.

1998-01-01

Heavy water plants realize the primary isotopic concentrations of water using H 2 O-H 2 S chemical exchange and they are chemical plants. As these plants are handling and spreading large quantities of hydrogen sulphide (high toxic, corrosive, flammable and explosive as) maintained in the process at relative high temperatures and pressures, it is required an assessing of risks associated with the potential accidents. The H 2 S released in atmosphere as a result of an accident will have negative consequences to property, population and environment. This paper presents a model of consequences quantitative assessment and its outcome for the most dangerous accident in heavy water plants. Several states of the art risk based methods were modified and linked together to form a proper model for this analyse. Five basic steps to identify the risks involved in operating the plants are followed: hazard identification, accident sequence development, H 2 S emissions calculus, dispersion analyses and consequences determination. A brief description of each step and some information of analysis results are provided. The accident proportions, the atmospheric conditions and the population density in the respective area were accounted for consequences calculus. The specific results of the consequences analysis allow to develop the plant's operating safety requirements so that the risk remain at an acceptable level. (authors)

A real-time tritium-in-water monitor for measurement of heavy water leak to the secondary coolant

International Nuclear Information System (INIS)

Rathnakaran, M.; Ravetkar, R.M.; Samant, R.K.; Abani, M.C.

2000-01-01

The paper describes the development and evaluation of on-line, real-time tritium in water monitor for detection and measurement of heavy water leak to the secondary coolant in a Pressurised Heavy Water Reactor. The detector used for this is a plastic scintillator film, made in the form of sponge and housed in a flow cell which is used for measurement of tritium activity present in heavy water. Two photomultiplier tubes are optically coupled on either face of the flow cell detector and measurement is done in coincidence mode. The sample water is continuously passed through the flow cell detector and a continuous measurement of tritium activity is carried out. It is observed that the impurities in the process water sample are gradually trapped in the flow cell, which affects the transparency of the detector with use. This reduces the sensitivity of the system. In addition, chlorine, which is added in the sample water, to arrest the fungus formation, creates chemiluminescence which interfere the measurement. To improve the sample quality as well as to eliminate the chemiluminescence created by chlorine, sample conditioner consisting of polypropylene candle, activated charcoal and glass fibre filter paper is developed. Polypropylene candle traps particulates above 5 μm pore size, activated charcoal absorbs organic compounds, free chlorine, fungus and turbidity and glass fibre filter paper stops submicron size particles. The measurement is also affected by the interference of dissolved argon-41 in the sample water. A bubbler system developed at BARC is used to strip the dissolved Ar-41 present in the sample which enables the system to measure tritium in presence of this interfering radioactive gas. The microprocessor based electronic system, used in the monitor provides the facility for selection of counting time and thereby improving the counting statistics. Alarm circuit is provided to give timely alarm when the tritium activity concentration exceeds the preset level

Problems connected with the production of heavy water in France; Problemes relatifs a la production d'eau lourde en France

Energy Technology Data Exchange (ETDEWEB)

Roth, E [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1956-07-01

The decision to study the nuclear energy in France in 1945 has seen the construction of the first natural uranium reactor for research purpose only, Zoe reactor. The utilization of heavy water as moderator was motivated by permitting the economical utilization of natural uranium oxides as fuel and a good handling. The five tons of heavy water required by the Zoe reactor were initially obtained from Norway production. With nuclear development and the construction of the first power reactors for electricity production, the demand in heavy water increased. The heavy water production by French industry became of a great interest. The first production started in the southwest of France using a fertilizers production plant and the electrolytic process used in Norway. The electrolytic process of hydrogen was quickly limited by the limited number of large fertilizers plants in France. Thus, in 1953, French nuclear research concentrated on the distillation of liquid hydrogen and water distillation for the heavy water production. The liquid hydrogen distillation presents a better yield in heavy water extraction than the electrolytic process but it was still depending from large fertilizers production plants. Although the water distillation process is simple, the high purity required for nuclear uses induced a high cost. The advantages and disadvantages of these two processes are discussed as well as others heavy water production processes using concentration process of already enriched water and the prospect of the use of the natural gas from the Lacq deposit. Economical aspect and cost production for each of heavy water production processes will be also discussed. (M.P.)

Operating experiences of Heavy Water Plant at Talcher using bithermal ammonia-hydrogen exchange process (Paper No. 1.9)

International Nuclear Information System (INIS)

Haldar, T.K.; Manoj Kumar; Ramamurty, C.B.

1992-01-01

A heavy water plant employing bithermal ammonia-hydrogen exchange process was set up at Talcher (India). The energy consumption in the process is lower as compared to monothermal process. The plant performance was affected by various problems and has resulted in low heavy water production. The problems are: (i)formation of solid deposits, (ii)inability of exchange towers to process design gas flow rates, (iii)inadequate exchange efficiency of the sieve trays provided as exchange trays, and (iv)differential amide concentration in different plant sections. These problems and their effect on the overall plant performance are discussed in detail and modifications to improve the performance are suggested. (author). 4 figs

Manufacturing opportunities in the Canadian CANDU and heavy water programs

International Nuclear Information System (INIS)

Reny, J.P.

The volume of business available to Canadian manufacturers of CANDU power plant and heavy water plant components is analyzed over about the next 10 years. Implications of exported nuclear technology and plants are explored. (E.C.B.)

The effect of using waste water for tomato

International Nuclear Information System (INIS)

Khan, M.J.; Jan, M.T.; Farahatullah; Khan, N.U.; Arif, M.; Perveen, S; Alam, S.; Jan, A.U.

2011-01-01

Field experiment near Palosi drain was conducted to study the effect of tube well (TW) and waste water (WW) with or without basal dose of NP and K on the yield and heavy metal uptake of tomato during 2008. The soil of the experimental site was sandy loam, slightly alkaline, moderately calcareous with phyto toxically high concentration of Cu, Fe and Mn while Cd, Cr, Ni, Pb and Zn were less than the levels considered toxic to the plants. The tomato biomass was significantly (p<0.05) affected by different treatments. Taller plants and higher biomass was produced in plots receiving WW with or without NP and K and TW water receiving basal dose of NP and K while lower biomass and shorter plants were produced in plots receiving only TW water indicating the nutritive value of WW application. The results of metal concentration in leaves and fruit showed that with exception of Cd, there were significant variation (p<0.05) in the plant uptake of metals when irrigated with different supply of irrigation water. The overall results showed that leaves accumulated higher concentration (with exception of Cu) of heavy metals studied compared to fruit. The concentration of Cr, Fe, Mn Pb and Zn in leaves was above the permissible limits when irrigated with waste water while waste water supplemented with fertilizers showed reduction in heavy metals uptake. The concentration of Fe and Pb was above the permissible limits in fruits indicating toxicity. It was also noted that plants receiving sole application of WW accumulated more heavy metals compared to WW plus half dose of NP and K while the TW irrigated plots accumulated less heavy metals indicating that their was no build up of heavy metals in the river bed soils because of its coarse texture. It can be concluded that tomato can be irrigated with effluents containing moderate supply of heavy metals on coarse textured soil. (author)

Coal consumption minimizing by increasing thermal energy efficiency at ROMAG-PROD Heavy Water Plant

International Nuclear Information System (INIS)

Preda, Marius Cristian

2006-01-01

ROMAG-PROD Heavy Water Plant is a large thermal energy consumer using almost all the steam output from ROMAG-TERMO Power Plant - the steam cost weight in the total heavy water price is about 40%. The steam consumption minimizing by modernization of isotopic exchange facilities and engineering development in ROMAG-PROD Heavy Water Plant results in an corresponding decrease of coal amount burned at ROMAG-TERMO boilers. This decrease could be achieved mainly by the followings ways: - Facility wrappings integrity; - High performance heat exchangers; - Refurbished heat insulations; - Modified condenser-collecting pipeline routes; - High performance steam traps; - Heat electric wire. When coal is burned in Power Plant burners to obtain thermal energy, toxic emissions results in flue gases, such as: - CO 2 and NO x with impact on climate warming; - SO 2 which results in ozone layer thinning effect and in acid rain falls. From the value of steam output per burned coal: 1 GCal steam = 1.41 tone steam = 0.86 thermal MW = 1.1911 tones burned coal (lignite), it is obvious that by decreasing the thermal energy consumption provided for ROMAG PROD, a coal amount decrease is estimated at about 45 t/h, or about 394,200 t/year coal, which means about 10% of the current coal consumption at ROMAG-TERMO PP. At the same time, by reducing the burned coal amount, an yearly decrease in emissions into air to about 400,000 tones CO 2 is expected

National symposium on commissioning and operating experiences in heavy water plants and associated chemical industries [Preprint volume

International Nuclear Information System (INIS)

1992-02-01

A symposium on commissioning and operating experiences in heavy water plants and associated chemical industries (SCOPEX-92) was organised to share the experience and exchange the ideas among plant operators, designers, consultants and vendors in the areas of operation, commissioning and equipment performance. This pre-print volume has been brought out as an integrated source of information on commissioning and operation of heavy water plants. The following aspects of heavy water plants are covered: commissioning and operation, instrumentation and control, and safety and environment. (V.R.)

The need for accurate deuterium analysis in a heavy water plant and its achievement

International Nuclear Information System (INIS)

Singh, R.R.; Pradhan, D.G.

1979-01-01

Importance of Mass Spectrometer as an analytical tool for deuterium analysis in heavy water plants is discussed. Some of the important requirements such as memory effect and H 3 + correction are described with reference to the Mass Spectrometer used at HWP (Talcher). For achieving the accuracy required, use of international deuterium standards and error estimation found by intercalibration are discussed. (auth.)

Heavy water GS process R and D achievements

International Nuclear Information System (INIS)

Bancroft, A.R.

1978-10-01

R and D support of Canadian heavy water production plants during the past five years has involved mainly AECL and Ontario Hydro, and their contractors. Testing has been done in the production plants, in two pilot plants and in research laboratories on topics that include sieve tray design, in-plant behaviour of oil and sulfur and choice of antifoam agent to control excessive foaming. The benefits are increased production through higher plant flows and higher extraction of deuterium from the feed, less down time because of process problems and lower cost for materials used to control water chemistry. (author)

Modeling Adsorption Kinetics (Bio-remediation of Heavy Metal Contaminated Water)

Science.gov (United States)

McCarthy, Chris

My talk will focus on modeling the kinetics of the adsorption and filtering process using differential equations, stochastic methods, and recursive functions. The models have been developed in support of our interdisciplinary lab group which is conducting research into bio-remediation of heavy metal contaminated water via filtration through biomass such as spent tea leaves. The spent tea leaves are available in large quantities as a result of the industrial production of tea beverages. The heavy metals bond with the surfaces of the tea leaves (adsorption). Funding: CUNY Collaborative Incentive Research Grant.

Modeling the transport of hydrogen in the primary coolant of pressurized heavy water reactors

International Nuclear Information System (INIS)

Subramanian, H.; Velmurugan, S.; Narasimhan, S.V.; Jain, A.K.; Dash, S.C.

2008-01-01

Heavy water (D 2 O) is used in primary heat transport systems of PHWRs. To suppress the radiolysis of heavy water and to control oxygen, hydrogen is added at regular intervals to the primary heat transport system. The added hydrogen finds it way to the heavy water storage tank after passing through the bleed condenser. Owing to the different temperatures and two phase region present in these systems, hydrogen gets redistributed. It is important to know the concentration of dissolved hydrogen in these regions in order to ensure a steady state dissolved hydrogen concentration in the primary system. Different power stations report variations in the frequency and quantity of hydrogen added to achieve the prescribed steady state level. This paper makes an attempt to account for the inventory of hydrogen and model its transport in PHT system. (author)

The effectiveness of spent coffee grounds and its biochar on the amelioration of heavy metals-contaminated water and soil using chemical and biological assessments.

Science.gov (United States)

Kim, Min-Suk; Min, Hyun-Gi; Koo, Namin; Park, Jeongsik; Lee, Sang-Hwan; Bak, Gwan-In; Kim, Jeong-Gyu

2014-12-15

Spent coffee grounds (SCG) and charred spent coffee grounds (SCG-char) have been widely used to adsorb or to amend heavy metals that contaminate water or soil and their success is usually assessed by chemical analysis. In this work, the effects of SCG and SCG-char on metal-contaminated water and soil were evaluated using chemical and biological assessments; a phytotoxicity test using bok choy (Brassica campestris L. ssp. chinensis Jusl.) was conducted for the biological assessment. When SCG and SCG-char were applied to acid mine drainage, the heavy metal concentrations were decreased and the pH was increased. However, for SCG, the phytotoxicity increased because a massive amount of dissolved organic carbon was released from SCG. In contrast, SCG-char did not exhibit this phenomenon because any easily released organic matter was removed during pyrolysis. While the bioavailable heavy metal content decreased in soils treated with SCG or SCG-char, the phytotoxicity only rose after SCG treatment. According to our statistical methodology, bioavailable Pb, Cu and As, as well as the electrical conductivity representing an increase in organic content, affected the phytotoxicity of soil. Therefore, applying SCG during environment remediation requires careful biological assessments and evaluations of the efficiency of this remediation technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Heavy water handbook. Evaluation of available thermophysical properties of heavy water (D2O) liquid and vapour

International Nuclear Information System (INIS)

Bukovsky, J.; Haack, K.; Wiig, P.

1993-01-01

Numerous publications on the thermophysical data of heavy water (D 2 O) have been published since D 2 O became commercially available in the 1930's. Some of these data are in mutual disagreement. This has led to confusion among the scientifical and technical staffs who needed the information on the D 2 O thermophysical data. Correct thermophysical data must be consistent, i.e. their mutual relations must be in accordance to the fundamental thermophysical laws. The work behind this publication has been focussed at collecting all avalilable D 2 O data and checking the data mutually by means of these fundamental thermophysical criteria. Depending on the various production methods, the oxygen content of the D 2 O is enriched more or less in the heavier oxygen isotopes 17 O and 18 O. This, together with the amount of impurities and dissolved gases in the D 2 O samples of the various references, might - to some extent - explain the discrepancies between the data sources. Only a few references contain information on these subjects. The D 2 O data sets which were found to be the most reliable are presented in chapter 9, in tables as well as in diagrams, together with the corresponding H 2 O data for comparison. The diagrams are commented for reliability where it was found necessary. Furthermore, the publication contains short descriptions on the heavy water sources, availability, production processes, economy, material and energy demands for production. A comprehensive list of references is enclosed. (author)

Study of heavy metal concentration (As, Ba, Cd, Hg, Pb, Crin water resources and river of Borujerd city in 2008-2009

Directory of Open Access Journals (Sweden)

bahram kamarehei

2010-02-01

Full Text Available with industrial and economic growth and different material production that humans gained from natural resources for their comfort and walfare, inwardly introduced toxic material and heavy metal entered environment that there created serious problems for themselves and environment. This study accomplished to determine heavy metal concentration (As, Ba, Cd, Hg, Pb, Crin water resources and river of Borujerd city in 2008-2009. Materials and Methods: This descriptive cross-sectional study was conducted to determine heavy metal concentration (As, Ba, Cd, Hg, Pb, Cr in water resources and river of Borujerd city. 54 samples of water were taken from 18 drinking water wells, and also in two times 8 samples of Borujerd river were taken from before and after the city. Then samples carried into the lab and were concentrated ten times using expressed methods and standard methods. Then heavy metal concentration determined by AAP (WFX 130 and results analyzed by SPSS and EXCEL software. Results: Heavy metal concentration average (As, Ba, Cd, Hg, Pb, Cr in drinking water wells were 0. 0, 0. 3222, 0. 0014, 0. 0002, 0. 0077 mg/l respectively. and heavy metal concentration in river water after the city has been increased than before the city. Conclusion: Results indicated that heavy metal concentration average in Borujerd drinking water wells were lower than standard amounts and drinking water wells didn’t pollute with heavy metal. But heavy metal concentration in river water after the city has been increased than the before of it because city waste water enters the city river.

New evaluation of thermal neutron scattering libraries for light and heavy water

Directory of Open Access Journals (Sweden)

Marquez Damian Jose Ignacio

2017-01-01

Full Text Available In order to improve the design and safety of thermal nuclear reactors and for verification of criticality safety conditions on systems with significant amount of fissile materials and water, it is necessary to perform high-precision neutron transport calculations and estimate uncertainties of the results. These calculations are based on neutron interaction data distributed in evaluated nuclear data libraries. To improve the evaluations of thermal scattering sub-libraries, we developed a set of thermal neutron scattering cross sections (scattering kernels for hydrogen bound in light water, and deuterium and oxygen bound in heavy water, in the ENDF-6 format from room temperature up to the critical temperatures of molecular liquids. The new evaluations were generated and processable with NJOY99 and also with NJOY-2012 with minor modifications (updates, and with the new version of NJOY-2016. The new TSL libraries are based on molecular dynamics simulations with GROMACS and recent experimental data, and result in an improvement of the calculation of single neutron scattering quantities. In this work, we discuss the importance of taking into account self-diffusion in liquids to accurately describe the neutron scattering at low neutron energies (quasi-elastic peak problem. To improve modeling of heavy water, it is important to take into account temperature-dependent static structure factors and apply Sköld approximation to the coherent inelastic components of the scattering matrix. The usage of the new set of scattering matrices and cross-sections improves the calculation of thermal critical systems moderated and/or reflected with light/heavy water obtained from the International Criticality Safety Benchmark Evaluation Project (ICSBEP handbook. For example, the use of the new thermal scattering library for heavy water, combined with the ROSFOND-2010 evaluation of the cross sections for deuterium, results in an improvement of the C/E ratio in 48 out of

New evaluation of thermal neutron scattering libraries for light and heavy water

Science.gov (United States)

Marquez Damian, Jose Ignacio; Granada, Jose Rolando; Cantargi, Florencia; Roubtsov, Danila

2017-09-01

In order to improve the design and safety of thermal nuclear reactors and for verification of criticality safety conditions on systems with significant amount of fissile materials and water, it is necessary to perform high-precision neutron transport calculations and estimate uncertainties of the results. These calculations are based on neutron interaction data distributed in evaluated nuclear data libraries. To improve the evaluations of thermal scattering sub-libraries, we developed a set of thermal neutron scattering cross sections (scattering kernels) for hydrogen bound in light water, and deuterium and oxygen bound in heavy water, in the ENDF-6 format from room temperature up to the critical temperatures of molecular liquids. The new evaluations were generated and processable with NJOY99 and also with NJOY-2012 with minor modifications (updates), and with the new version of NJOY-2016. The new TSL libraries are based on molecular dynamics simulations with GROMACS and recent experimental data, and result in an improvement of the calculation of single neutron scattering quantities. In this work, we discuss the importance of taking into account self-diffusion in liquids to accurately describe the neutron scattering at low neutron energies (quasi-elastic peak problem). To improve modeling of heavy water, it is important to take into account temperature-dependent static structure factors and apply Sköld approximation to the coherent inelastic components of the scattering matrix. The usage of the new set of scattering matrices and cross-sections improves the calculation of thermal critical systems moderated and/or reflected with light/heavy water obtained from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) handbook. For example, the use of the new thermal scattering library for heavy water, combined with the ROSFOND-2010 evaluation of the cross sections for deuterium, results in an improvement of the C/E ratio in 48 out of 65

Detection of heavy-water leaks in nuclear reactors : a novel method

International Nuclear Information System (INIS)

Murthy, M.S.; Gor, M.K.

2002-01-01

Technical Physics and Prototype Engineering Division, BARC has designed, developed and produced several high sensitivity mass spectrometer helium leak detectors over a period of two decades. Sometimes back, when there was a problem of detecting heavy water leaks in situ in one of the nuclear power reactors of the Department of Atomic Energy, it was referred to this division for a technical solution. After discussing with the site engineers, the various problems involved in the on-line detection of heavy water leaks especially near the end fittings of the coolant assemblies, a novel method of leak detection was developed. Some of the salient features of the method and the results obtained in the laboratory tests are given in this paper. (author)

The supply of steam from Candu reactors for heavy water production

International Nuclear Information System (INIS)

Robertson, R.F.S.

1975-09-01

By 1980, Canada's energy needs for D 2 O production will be 420 MW of electrical energy and 3600 MW of thermal energy (as steam). The nature of the process demands that this energy supply be exceptionally stable. Today, production plants are located at or close to nuclear electricity generating sites where advantage can be taken of the low cost of both the electricity and steam produced by nuclear reactors. Reliability of energy supply is achieved by dividing the load between the multiple units which comprise the sites. The present and proposed means of energy supply to the production sites at the Bruce Heavy Water Plant in Ontario and the La Prade Heavy Water Plant in Quebec are described. (author)

Heavy water handbook. Evaluation of presently available thermophysical properties of heavy water (D2O) liquid and vapour

International Nuclear Information System (INIS)

Bukovsky, J.; Haack, K.

1994-08-01

Many publication on the thermophysical properties of heavy water (D 2 O) have appeared since D 2 O became commercially available in the 1930's. Some for the data contradict one another and this has led to confusion when information is needed on D 2 O thermophysical data. Correct thermophysical data must be consistent, i.e. their mutual dependence must be consistent with fundamental thermophysical laws. The work behind this publication has focused on collecting all available D 2 O data and checking them against these fundamental thermophysical criteria. Depending on the various production methods for D 2 O, its oxygen content is enriched more or less by the heavier oxygen isotopes 17 O and 18 O. This, together with the amount of impurities and dissolved gases in the D 2 O samples of the various references, might - to some extent - explain the discrepancies found between the data. Only a few references contain information on these subjects. The D 2 O data sets found to be the most reliable are presented in Chapter 9, in tables as well as in diagrams, together with the corresponding H 2 O data for comparison. Comments on the reliability of the diagrams are given where necessary. Furthermore, short descriptions are given of heavy water sources, availability, production processes, economy, material and energy requirements for the production process. Finally a comprehensive list of references and an author index are included. (au)

Estimation of some heavy metals in polluted well water and mercury accumulation in broiler organs

OpenAIRE

Hussein, Hussein Khamis; Abu-Zinadah, Osama Abdullah; EL-Rabey, Haddad Abdulsameih; Meerasahib, Mohammed Fareez

2013-01-01

The aim of this study was to investigate the relationship between the concentrations of heavy metals in well water and bioaccumulation of the most abundant metals in chicken tissues in some areas in the province of Mecca Almokaramah, Saudi Arabia. Among the heavy metals (Cd, Zn, Cr, Mn, Cu Hg, Pb and Ni) studied, mercury (Hg) revealed highest in concentration in well waters. The concentration of mercury in the ground water, beside in liver, kidney, muscle and blood samples of ten chickens fro...

Heavy metal and radioactivity measurements in fish, water, plants and soils in tin-mining pool

International Nuclear Information System (INIS)

Muhammad Samudi Yasir; Norlaili Ahmad Kabir; Redzuwan Yahaya; Amran Abdul Majid

2008-01-01

Malaysia aggressively reclaimed most of their disused tin-mining pool especially for agricultural activities, freshwater fish farming area, recreational area, houses area and even as an industrial area. Past mining activities might induced the concentration of naturally occurring radionuclide (NORM) and heavy metal at the disused tin-mining pool ecosystem. A study has been conducted on the status of heavy metal (Hf, Zr, Mn, Cu, Zn, As, Cd, Sn, Sb, Ba, Hg and Pb) concentration and naturally occurring radionuclide activity in fish, water, plants and sediments at three different disused tin-mining pool near by Sepang and Puchong, Selangor Darul Ehsan. Sample of fish, water, plant and sediment being analyze using ICP-MS. The concentrations of heavy metal in sediment and plant are higher than its concentrations in fish and followed by water. The highest concentration of heavy metal in sediment and water is barium, whereas the highest concentration of heavy metal in fish and plant is zinc and manganese. The result also showed that only mercury level in fish collected in second disused tin-mining pool (0.53 ± 0.20 mg/ kg) is exceed the maximum limit (0.5 mg/ kg) prescribe by the Malaysian Food Act (Act 281). The activity of U-238 and Th-232 in sediment was found to be relatively higher than its activity in fish, plant or water (30.76 ± 2.71 to 35.34 ± 0.27 Bq/ kg) and (9.37 ± 2.30 - 18.86 ± 2.60 Bq/ kg). The determination of K-40 activity showed that it is highly contained in plant and fish than in sediment or water. (author)

Gas stripping and recirculation process in heavy water separation plant

International Nuclear Information System (INIS)

Nazzer, D.B.; Thayer, V.R.

1976-01-01

Hydrogen sulfide is stripped from hot effluent, in a heavy water separation plant of the dual temperature isotope separation type, by taking liquid effluent from the hot tower before passage through the humidifier, passing the liquid through one or more throttle devices to flash-off the H 2 S gas content, and feeding the gas into an absorption tower containing incoming feed water, for recycling of the gas through the process

The Influence of Industrial Waste on Pesticide and Heavy Metal Conetnts in Cipinang-Sunter River Water Jakarta

International Nuclear Information System (INIS)

Ulfa, T S; Mellawati, J; Sofni, M C

1996-01-01

The measurement of pesticide and heavy metal contents of river water in upperstream (around some factories), and downstream (housing area), along Cipinang-Sunter river Jakarta, on February-June 1996 had been done. The aim of the measurement was to get information about the influence of factories waste on pesticide and heavy metal contents in the Cipinang river water. Gas and liquid chromatographis were used to measure the pesticide content and X-ray fluorecence spectrometry was used to measure the heavy metals content. Result of the measurements showed that Cipinang river water has contained some organochlorin pesticides, i.e., BHC, a and b endosulfan, dieldrin, pp-DDE, and heavy metals, i.e., Ti, V, Cr, Fe, Ni, Cu, Zn, and Pb

Heavy metals and hydrocarbon concentrations in water, sediments and tissue of Cyclope neritea from two sites in Suez Canal, Egypt and histopathological effects.

Science.gov (United States)

Sharaf, Hesham M; Shehata, Abdalla M

2015-01-01

Heavy metals and hydrocarbons are of the most common marine pollutants around the world. The present study aimed to assess the concentration of petroleum hydrocarbons and heavy metals in tissues of the snail cyclope neritea, water and sediments from two sites of the study area (Temsah lake and Suez canal) represent polluted and unpolluted sites respectively. The results showed that, the levels of the heavy metals (Pb, Cd, Co, Mg and Zn) in the polluted area have reached harmful limits recorded globally. Lead in water, sediment and tissue of the snail reached to 0.95 ppm, 4.54 ppm and 7.93 ppm respectively. Cadmium reached 0.31 ppm, 1.15 ppm and 3.08 ppm in the corresponding samples. Cobalt was not detected in water, but it reached 1.42 ppm and 10.36 ppm in the sediment and snails tissue respectively. Magnesium in water, sediment and tissue of the snail reached 3.73 ppm, 9.44 ppm and12.6 ppm respectively. Zinc reached 0.11 ppm, 3.89 ppm and 12.60ppm in the corresponding samples. Meanwhile, hydrocarbons in the polluted area (site1) reached 110.10 μg/L, 980.15 μg/g and 228.00 μg/g in water sediment and digestive gland tissues of the snails respectively. Whereas, hydrocarbons in the unpolluted area (site2) were estimated as 14.20 μg/L, 55.60 μg/g and 22.66 μg/g in water, sediment and tissue of the snails respectively. The combination of histopathological image with monitoring of the metal level in the digestive gland of the present snail provides an important tool for early detection of impending environmental problems and potential public health issues. Petroleum hydrocarbons are toxic to the marine fauna when present above certain limit in the marine water. The major detoxification organ in molluscs is the digestive gland, which has been used as a bioindicator organ for toxicity assessment. The effect of high crude oil on the digestive gland tubules of exposed snails when examined microscopically reveals a series of histological changes which indicates that the

Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation

International Nuclear Information System (INIS)

Hong, Nian; Zhu, Panfeng; Liu, An

2017-01-01

Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. - Highlights: • A model was developed to simulate heavy metal build-up loads on urban roads. • This model is based on artificial neural networks. • Land use fractions was used to model build-up loads on different particle sizes. • The maps of heavy metal spatial distribution and ecological risk were generated. • This model can be used for effective stormwater reuse strategy implementation. - Development of a robust modelling approach to mapping heavy metals build-up and their ecological risks for stormwater reuse safety.

What is safe and clean water in rural Bolivian communities? A preliminary investigation of heavy metal contamination in rural community water systems in the Bolivian Altiplano

Science.gov (United States)

Borella, M.; Guido, Z.; Borella, P.; Ketron, T.

2009-12-01

A proliferation of potable water systems utilizing groundwater is currently underway in the Lake Titicaca region of the Bolivian Altiplano. With the aid of national and international organizations, rural communities are developing groundwater sources because the region’s surface water is highly contaminated with waterborne pathogens—the primary factor contributing to high child mortality rates in developing nations. According to UNICEF, 86 percent of Bolivian families have access to “improved” water systems, which predominantly take the form of deep groundwater wells or contained natural springs. While the water systems have worked well to reduce pathogens in drinking water systems that cause illnesses such as dysentery, the water is rarely tested for heavy metal contamination, such as arsenic and lead. While bacteria analysis is essential, it is not the only component of healthy drinking water. Testing for heavy metals is especially important in the Bolivian Altiplano because abundant volcanic deposits and massive sulfide deposits suggest that in some areas it is likely that the water contains elevated concentrations of heavy metals. In this study, Terra Resource Development International, A California-based 502(c)3 nonprofit organization, partnered with Stanford University, the Technical University of Bolivia, and the Bolivian Geologic and Mining Survey to collect water samples in 36 rural community situated in four watersheds feeding into Lake Titicaca. Water was collected from shallow, hand dug wells, deep groundwater wells, springs, and small rivers in the Tiwanku, Laja, Batallas, Achacachi watersheds and were analyzed for inorganic contaminants. Samples were analyzed at Stanford’s Environmental Measurements Facility using the Inductively Coupled Plasma (ICP) Spectrometer for major ions and heavy metals. Results will help determine which, if any, community water systems are at risk of heavy metal contamination, where more comprehensive sampling is

Studies on corrosion inhibitors for the cooling water system at the Heavy Water Project, Kota

International Nuclear Information System (INIS)

Pillai, B.P.; Mehta, C.T.; Abubacker, K.M.

1986-01-01

The Heavy Water Project at Kota uses the water from the Rana Pratap Sagar Lake as coolant in the open recirculation system. In order to find suitable corrosion inhibitors for the above system, a series of laboratory experiments on corrosion inhibitors were carried out using the constructional materials of the cooling water system and a number of proprietary formulations and the results are tabulated. From the data thus generated through various laboratory experiments, the most useful ones have been recommended for application in practice. (author)

Role of knowledge based engineering in Heavy Water Plants and its relevance to chemical industry

International Nuclear Information System (INIS)

Sonde, R.R.

2002-01-01

The development of heavy water technology under the Department of Atomic Energy in India is carried out based on a mission oriented programme and this was backed up by a committed and highly trained manpower with a single minded pursuit to achieve the goal of making India self-sufficient in this challenging area. The paper gives step by step methodology followed in completion of the above mission which has become a benchmark in the chemical industry. A large sized chemical industry (Heavy Water plant being once such industry) has many features which are similar. The process design typically includes design of reactors, distillation columns, heat exchange networks, fluid transfer machinery, support utility systems etc. Besides, there are other issues like safety engineering, selection of materials, commissioning strategies and operating philosophies which are quite common to almost all chemical industries. Heavy water board has engineered and set up large scale heavy water plants and the technology for production of heavy water is completely assimilated in India and this paper tries to bring about some of the strategies which were instrumental in achieving this. The story of success in this technology can most certainly be followed in development of any other process technology. The important factors in the development of this technology is based on integration of R and D, process design, engineering backup, safety features, role of good construction and project management and good operating practices. One more important fact in this technology development is continuous improvement in operation and use of knowledge based engineering for debottlenecking. (author)

Plutonium Recycle Test Reactor (PRTR). Operating Experience and Supporting R and D, Its Application to Heavy-Water Power Reactor Design and Operation

Energy Technology Data Exchange (ETDEWEB)

Harty, H. [Battelle Memorial Institute, Pacific Northwest Laboratories, Richland, WA (United States)

1968-04-15

on PRTR experience. 4. Only pressure-tube inspection and primary system decontamination operations require additional downtime to that anticipated for light-water reactors. An improved pressure-tube monitoring system is required. Decontamination requires reactor defuelling and heavy-water removal for those procedures which are most effective. (author)

A study on the establishment of component/equipment performance criteria considering Heavy Water Reactor characteristics

Energy Technology Data Exchange (ETDEWEB)

Chang, Keun Sun; Kwon, Young Chul; Lee, Min Kyu; Lee, Yun Soo [Sunmoon Univ., Asan (Korea, Republic of); Chang, Seong Hoong; Ryo, Chang Hyun [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Soong Pyung; Hwnag, Jung Rye; Chung, Chul Kee [Chosun Univ., Gwangju (Korea, Republic of)

2002-03-15

Foreign and domestic technology trends, regulatory requirements, design and researches for heavy water reactors are analyzed. Safety design guides of Canada industry and regulatory documents and consultative documents of Canada regulatory agency are reviewed. Applicability of MOST guidance 16 Revision 'guidance for technical criteria of nuclear reactor facility' is reviewed. Specific performance criteria are established for components and facilities for heavy water reactor.

Analytical performance of refractometry in quantitative estimation of isotopic concentration of heavy water in nuclear reactor

International Nuclear Information System (INIS)

Dhole, K.; Ghosh, S.; Datta, A.; Tripathy, M.K.; Bose, H.; Roy, M.; Tyagi, A.K.

2011-01-01

The method of refractometry has been investigated for the quantitative estimation of isotopic concentration of D 2 O (heavy water) in a simulated water sample. Viability of Refractometry as an excellent analytical technique for rapid and non-invasive determination of D 2 O concentration in water samples has been demonstrated. Temperature of the samples was precisely controlled to eliminate effect of temperature fluctuation on refractive index measurement. Calibration performance by this technique exhibited reasonable analytical response over a wide range (1-100%) of D 2 O concentration. (author)

Supercooling of natural water, heavy water and of the blends H2O-D2O

International Nuclear Information System (INIS)

Lafargue, C.; Babin, L.; Clausse, D.; Lere-Porte, M.; Broto, F.

1975-01-01

It is shown that the coherency of the results of various measurements on water freezing temperatures proves that freezing temperatures must be dependent on the structure of the supercooled liquid. Recent experiments that confirm this interpretation are described: study of the stability of supercooled water as a function of time at fixed temperature, study of the influence of various thermal treatments on the behavior of supercooled water, study of the supercooling of heavy water and of D 2 O-H 2 O blends [fr

A new catalyst for heavy water production and its prospect

International Nuclear Information System (INIS)

Sato, Toshio; Ohkoshi, Sumio; Takahashi, Tomiki

1978-01-01

The heavy water production process utilizing isotope exchange reaction between liquid water and hydrogen is the most promising method. Study was made for developing highly active and long life catalyst practically applied for this process. As platinum is used as this catalyst, catalytic activities using varieties of Polapacs and Shodexes instead of active carbon as the carriers of platinum catalyst were investigated. It became clear that the catalytic activity using Pt/Shodex 104 (3 wt %) was 1000 times as high as the activity using Pt/active carbon (1 wt %). This method is considered to be reasonable enough economically. There are many problems which must be solved hereafter for its practical use, and the further studies are required regarding the following points; forming of catalyst, life of catalyst, mass production of catalyst, most appropriate counter flow reacting device of hydrophobic catalyst, pressure and temperature effects on reaction. (Kobatake, H.)

Numerical analysis on the calandria tubes in the moderator of a heavy water reactor using OpenFOAM and other codes

International Nuclear Information System (INIS)

Chang, S.M.; Kim, H.T.

2013-01-01

CANDU, a prototype of heavy water reactor is modeled for the moderator system with porous media buoyancy-effect heat-transfer turbulence model. OpenFOAM, a set of C++ classes and libraries developed under the object-oriented concept, is selected as the tool of numerical analysis. The result from this computational code is compared with experiments and other commercial code data through ANSYS-CFX and COMSOL Multi-physics. The three-dimensional code concerning buoyancy force, turbulence, and heat transfer is tested and shown to be successful for the analysis of thermo-hydraulic system of heavy water reactors. (authors)

Surface tension of normal and heavy water

International Nuclear Information System (INIS)

Straub, J.; Rosner, N.; Grigull, V.

1980-01-01

A Skeleton Table and simple interpolation equation for the surface tension of light water was developed by the Working Group III of the International Association for the Properties of Steam and is recommended as an International Standard. The Skeleton Table is based on all known measurements of the surface tension and individual data were weighted corresponding to the accuracy of the measurements. The form of the interpolation equation is based on a physical concept. It represents an extension of van der Waals-equation, where the exponent conforms to the 'Scaling Laws'. In addition for application purposes simple relations for the Laplace-coefficient and for the density difference between the liquid and gaseous phases of light water are given. The same form of interpolation equation for the surface tension can be used for heavy water, for which the coefficients are given. However, this equation is based only on a single set of data. (orig.) [de

Current state of knowledge of the concentration of mercury and other heavy metals in fresh water fish in Colombia

International Nuclear Information System (INIS)

Mancera Rodriguez, Nestor Javier; Alvarez Leon, Ricardo

2006-01-01

One of the most important environmental problems in the country refers to the indiscriminate use of chemical precursors in illicit activities, the use of heavy metals as mercury in mining activities, the spill of served waters and another type of compound related with the industrial activities of raw and the inadequate agricultural practices. This has led to chemical contamination especially by heavy metals, considered one of the most dangerous for the aquatic ecosystems and the present species in them. Fish have the capacity to store these compounds in their organism in a concentration higher than that in the surrounding environment (water), therefore, their concentration are important indicators of the contamination level, but also this implies that their consumption can become a serious health problem for the populations that feeds from them. The concentration of heavy metals in fish of fresh water is better known in the basin of the Magdalena river, especially in the region of the Mojana and in the marshes of the south of the department of Bolivar where the levels of contamination by mercury and other metals has been studied due to the development of multiple industrial activities, including gold mining and petrochemical industries. However, little is known in the country about the problem generated by the disposal heavy metals in rivers and lakes and their impact on the fish resource, deterioration of ecosystems and human health. Based in the current norms bio-assays have been used to check the effects of the aquatic contamination on fresh waters fish and the evaluation of at least three parameters (heavy metals, temperature, effluents) in eight species of fresh waters fish: carassius auratus, oreochromis spp., piractus brachypomus, prochilodus magdalenae, astyanax fasciatus, colossoma bidens, gambusia affinis and grundulus bogotensis

Effects of heavy particle irradiation on central nervous system

International Nuclear Information System (INIS)

Nojima, Kumie; Nakadai, Taeko; Khono, Yukio

2006-01-01

Effects of low dose heavy particle radiation to central nervous system were studied using human embryonal carcinoma (Ntera2=NT2) and Human neuroblastoma cell (NB1). They exposed to heavy ions and X ray 80% confluent cells in culture bottles. The cells were different type about growth and differentiation in the neuron. The apoptosis profile was measured by AnnexinV-EGFP, PI stained and fluorescence-activated cell sorter (FACS). Memory and learning function of adult mice were studied using water maze test after carbon- or iron-ion irradiation. Memory functions were rapidly decreased after irradiation both ions. Iron -ion group were recovered 20 weeks after irradiation C-ion group were recovered 25 weeks after irradiation. Tier memory were still keep at over 100 weeks after irradiation. (author)

Baryons in the heavy quark effective theory

International Nuclear Information System (INIS)

Mannel, T.; Roberts, W.; Ryzak, Z.

1990-08-01

We show how to incorporate baryons in the heavy quark effective theory. A convenient formalism is exhibited and applied to semileptonic weak decays of heavy baryons and to exclusive production of heavy baryons in e + e - annihilation. (orig.)

Simple method of measuring pulmonary extravascular water using heavy water

Energy Technology Data Exchange (ETDEWEB)

Basset, G; Moreau, F; Scaringella, M; Tistchenko, S; Botter, F; Marsac, J

1975-11-20

The field of application of the multiple indicators dilution method in human pathology, already used to study pulmonary edema, can be extended to cover the identification and testing of all conditions leading to increase lung water. To be really practical it must be simple, fast, sensitive, inexpensive and subject to repetition; the use of non-radioactive tracers is implied. Indocyanine Green and heavy water were chosen respectively as vascular and diffusible indicators. Original methods have been developed for the treatment and isotopic analysis of blood: mass spectrometric analysis of aqueous blood extracts after deproteinisation by zinc sulphate then rapid distillation of the supernatant under helium; infrared analysis either of acetone extracts from small blood samples (100..mu..litre) or of blood itself in a continuous measurement. The infrared technique adopted has been used on rats and on men in normal and pathological situations. The results show that the method proposed for the determination of pulmonary extravascular water meets the requirements of clinicians while respecting the patients' safety, and could be generalized to other organs.

Radiation dose due to radon and heavy metal analysis in drinking water samples of Jammu district, J. and K., India

International Nuclear Information System (INIS)

Ajay Kumar; Kaur, Manpreet; Sharma, Sumit; Mehra, Rohit; Sharma, Dinesh Kumar

2015-01-01

The aim of this study is to determine the relationship between the contaminant drinking water and its impact on human health. The most contaminants of ground water are heavy metals like arsenic, cadmium, mercury, copper, zinc and etc. These heavy metals particularly cause strong toxicity even at low concentration. Heavy metals are considered to be the major pollutants of water sources. Heavy metal toxicity can result in damaged or reduced mental and central nervous function, lower energy levels and damage to blood composition, lungs, kidneys, liver and other vital organs. Physicochemical parameters such as pH, electrical conductivity, total dissolved solids, salinity and dissolved oxygen were analyzed. For revealing the ground water quality and soil quality in area of Jammu, a total of 40 samples have been collected and analyzed for different kind of heavy metal concentration. These heavy metal concentrations in water samples were analyzed by Atomic Absorption Spectrophotometer (AAS). The results were compared with WHO, ED, ICMR and Indian. The trace metal analysis is not on the exceeding side of the permissible limit in all the samples. Along with the heavy metal concentration in water samples and soil samples, the radon concentration also measured by using RAD7. The values of radon concentration in drinking water samples were also compared within the safe limit recommended by different health agencies. (author)

Neutron emission during lithium deuteride hydration in heavy water

International Nuclear Information System (INIS)

Arzhannikov, A.V.; Kezerashvili, G.Ya.; Muratov, V.V.; Sinitskij, S.L.

1989-01-01

An experiment on neutron detection during lithium deuteride hydration in heavy water using a system of SNM-17 or SNM-18 gas counters was set up. Signals were simultaneously detected by 6 counters and the data were stored in a computer. At the same time the temperature of the reaction ampule external surface was measured. It was found that the neutron number per 1 gram of lithium deuteride reacted with water in the ampule was equal to several dozens if their initial energy was about 2.5 MeV. 4 refs.; 2 figs

Applying CFD in the Analysis of Heavy Oil/Water Separation Process via Hydrocyclone

Directory of Open Access Journals (Sweden)

K Angelim

2017-06-01

Full Text Available In recent years most of the oil reserves discovered has been related to heavy oil reservoirs whose reserves are abundant but still show operational difficulties. This fact provoked great interest of the petroleum companies in developing new technologies for increasing the heavy oil production. Produced water generation, effluent recovered from the production wells together with oil and natural gas, is among the greatest potential factors for environmental degradation. Thus, a new scenario of the oil industry appears requiring improvement in treatment units for produced water. Among the technological improvements in the facilities, the use of hydrocyclones has been applied in the treatment of the oily water. In this sense, this study aims to investigate numerically the separation process of heavy oil from a water stream via hydrocyclone, using the computational fluid dynamics technique. In the mathematical modeling was considered a two-phase, three-dimensional, stationary, isothermal and turbulent flow. Results of streamlines, pressure and volume fraction fields of the involved phases (oil and water into the hydrocyclone, and mechanical efficiency and pumping power of the fluids are shown and analyzed. In conclusion, it seems that with increasing fluid input velocity in the device there is an increase in pressure drop, indicating a greater pumping energy consumption of the mixture, and greatly influences the separation process efficiency.

Graphite-moderated and heavy water-moderated spectral shift controlled reactors; Reactores de moderador solido controlados por desplazamiento espectral

Energy Technology Data Exchange (ETDEWEB)

Alcala Ruiz, F

1984-07-01

It has been studied the physical mechanisms related with the spectral shift control method and their general positive effects on economical and non-proliferant aspects (extension of the fuel cycle length and low proliferation index). This methods has been extended to non-hydrogenous fuel cells of high moderator/fuel ratio: heavy water cells have been con- trolled by graphite rods graphite-moderated and gas-cooled cells have been controlled by berylium rods and graphite-moderated and water-cooled cells have been controlled by a changing mixture of heavy and light water. It has been carried out neutron and thermal analysis on a pre design of these types of fuel cells. We have studied its neutron optimization and their fuel cycles, temperature coefficients and proliferation indices. Finally, we have carried out a comparative analysis of the fuel cycles of conventionally controlled PWRs and graphite-moderated, water-cooled and spectral shift controlled reactors. (Author) 71 refs.

Novel forward osmosis process to effectively remove heavy metal ions

KAUST Repository

Cui, Yue; Ge, Qingchun; Liu, Xiangyang; Chung, Neal Tai-Shung

2014-01-01

In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

Novel forward osmosis process to effectively remove heavy metal ions

KAUST Repository

Cui, Yue

2014-10-01

In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

Licensing assessment of the Candu Pressurized Heavy Water Reactor. Preliminary safety information document. Volume II

International Nuclear Information System (INIS)

1977-06-01

ERDA has requested United Engineers and Constructors (UE and C) to evaluate the design of the Canadian natural uranium fueled, heavy water moderated (CANDU) nuclear reactor power plant to assess its conformance with the licensing criteria and guidelines of the U.S. Nuclear Regulatory Commission (USNRC) for light water reactors. This assessment was used to identify cost significant items of nonconformance and to provide a basis for developing a detailed cost estimate for a 1140 MWe, 3-loop Pressurized Heavy Water Reactor (PHWR) located at the Middletown, USA Site

Good practices in heavy water reactor operation

International Nuclear Information System (INIS)

2010-06-01

The value and importance of organizations in the nuclear industry engaged in the collection and analysis of operating experience and best practices has been clearly identified in various IAEA publications and exercises. Both facility safety and operational efficiency can benefit from such information sharing. Such sharing also benefits organizations engaged in the development of new nuclear power plants, as it provides information to assist in optimizing designs to deliver improved safety and power generation performance. In cooperation with Atomic Energy of Canada, Ltd, the IAEA organized the workshop on best practices in Heavy Water Reactor Operation in Toronto, Canada from 16 to 19 September 2008, to assist interested Member States in sharing best practices and to provide a forum for the exchange of information among participating nuclear professionals. This workshop was organized under Technical Cooperation Project INT/4/141, on Status and Prospects of Development for and Applications of Innovative Reactor Concepts for Developing Countries. The workshop participants were experts actively engaged in various aspects of heavy water reactor operation. Participants presented information on activities and practices deemed by them to be best practices in a particular area for consideration by the workshop participants. Presentations by the participants covered a broad range of operational practices, including regulatory aspects, the reduction of occupational dose, performance improvements, and reducing operating and maintenance costs. This publication summarizes the material presented at the workshop, and includes session summaries prepared by the chair of each session and papers submitted by the presenters

Fuel enrichment reduction for heavy water moderated research reactors

International Nuclear Information System (INIS)

McCulloch, D.B.

1984-01-01

Twelve heavy-water-moderated research reactors of significant power level (5 MW to 125 MW) currently operate in a number of countries, and use highly enriched uranium (HEU) fuel. Most of these reactors could in principle be converted to use uranium of lower enrichment, subject in some cases to the successful development and demonstration of new fuel materials and/or fuel element designs. It is, however, generally accepted as desirable that existing fuel element geometry be retained unaltered to minimise the capital costs and licensing difficulties associated with enrichment conversion. The high flux Australian reactor, HIFAR, at Lucas Heights, Sydney is one of 5 Dido-class reactors in the above group. It operates at 10 MW using 80% 235 U HEU fuel. Theoretical studies of neutronic, thermohydraulic and operational aspects of converting HIFAR to use fuels of reduced enrichment have been made over a period. It is concluded that with no change of fuel element geometry and no penalty in the present HEU fuel cycle burn-up performance, conversion to MEU (nominally 45% 235 U) would be feasible within the limits of current fully qualified U-Al fuel materials technology. There would be no significant, adverse effects on safety-related parameters (e.g. reactivity coefficients) and only small penalties in reactor flux. Conversion to LEU (nominally 20% 235 U) a similar basis would require that fuel materials of about 2.3 g U cm -3 be fully qualified, and would depress the in-core thermal neutron flux by about 15 per cent relative to HEU fuelling. In qualitative terms, similar conclusions would be expected to hold for a majority of the above heavy water moderated reactors. (author)

Contribution of Heavy Water Board in nuclear fuel cycle technologies. Contributed Paper IT-03

International Nuclear Information System (INIS)

Mohanty, P.R.

2014-01-01

The three stage Indian nuclear power programme envisages use of closed nuclear fuel cycle and thorium utilization as its mainstay for long term energy security on sustainable basis. India is committed to realize this objective through the development and deployment of frontier technologies pertaining to all aspects of a closed nuclear fuel cycle. Comprehensive indigenous capabilities have been developed in all aspects of nuclear power and associated fuel cycles. Heavy Water Board (HWB), with its abiding objective of fulfilling demand of heavy water for India's flourishing nuclear power program, is one of the frontrunner in Nuclear Fuel Cycle Technology. HWB is now engaged in wide spectrum of activities in various facets of fuel cycle covering all the three stages of Indian Nuclear Power Programme. HWB is contributing to Nuclear Fuel Cycle through large scale production and sustained supply of key input materials including heavy water, solvents for nuclear hydrometallurgy, 10 B enriched boron etc

Seasonal assessment, treatment and removal of heavy metal concentrations in a tropical drinking water reservoir

Directory of Open Access Journals (Sweden)

Mustapha Moshood Keke

2016-06-01

Full Text Available Heavy metals are present in low concentrations in reservoirs, but seasonal anthropogenic activities usually elevate the concentrations to a level that could become a health hazard. The dry season concentrations of cadmium, copper, iron, lead, mercury, nickel and zinc were assessed from three sites for 12 weeks in Oyun reservoir, Offa, Nigeria. Triplicate surface water samples were collected and analysed using atomic absorption spectrophotometry. The trend in the level of concentrations in the three sites is site C > B > A, while the trend in the levels of the concentrations in the reservoir is Ni > Fe > Zn > Pb > Cd > Cu > Hg. Ni, Cd, Pb and Hg were found to be higher than the WHO guidelines for the metals in drinking water. The high concentration of these metals was from anthropogenic watershed run-off of industrial effluents, domestic sewages and agricultural materials into the reservoir coming from several human activities such as washing, bathing, fish smoking, especially in site C. The health effects of high concentration of these metals in the reservoir were highlighted. Methods for the treatment and removal of the heavy metals from the reservoir during water purification such as active carbon adsorption, coagulation-flocculation, oxidation-filtration, softening treatment and reverse osmosis process were highlighted. Other methods that could be used include phytoremediation, rhizofiltration, bisorption and bioremediation. Watershed best management practices (BMP remains the best solution to reduce the intrusion of the heavy metals from the watershed into the reservoir.

Seismic re-evaluation of piping systems of heavy water plant, Kota

International Nuclear Information System (INIS)

Mishra, Rajesh; Soni, R.S.; Kushwaha, H.S.; Venkat Raj, V.

2002-05-01

Heavy Water Plant, Kota is the first indigenous heavy water plant built in India. The plant started operation in the year 1985 and it is approaching the completion of its originally stipulated design life. In view of the excellent record of plant operation for the past so many years, it has been planned to carry out various exercises for the life extension of the plant. In the first stage, evaluation of operation stresses was carried out for the process critical piping layouts and equipment, which are connected with 25 process critical nozzle locations, identified based on past history of the plant performance. Fatigue life evaluation has been carried out to fmd out the Cumulative Usage Factor, which helps in arriving at a decision regarding the life extension of the plant. The results of these exercises have been already reported separately vide BARC/200I /E/O04. In the second stage, seismic reevaluation of the plant has been carried out to assess its ability to maintain its integ:rity in case of a seismic event. The aim of this exercise is to assess the effects of the maximum probable earthquake at the plant site on the various systems and components of the plant. This exercise is further aimed at ensuring the adequacy of seismic supports to maintain the integrity of the system in case of a seismic event and to suggest some retrofitting measures, if required. Seismic re-evaluation of the piping of Heavy Water Plant, Kota has been performed taking into account the interaction effects from the connected equipment. Each layout has been qualified using the latest provisions of ASME Code Section III, Subsection ND wherein the earthquake loading has been considered as a reversing dynamic load. The maximum combined stresses for all the layouts due to pressure, weight and seismic loadings have been found to be well within the code allowable limit. Therefore, it has been concluded that during a maximum probable seismic event, the possibility of pipe rupture can be safely

A Review of Laboratory-Scale Research on Upgrading Heavy Oil in Supercritical Water

Directory of Open Access Journals (Sweden)

Ning Li

2015-08-01

Full Text Available With the growing demand for energy and the depletion of conventional crude oil, heavy oil in huge reserve has attracted extensive attention. However, heavy oil cannot be directly refined by existing processes unless they are upgraded due to its complex composition and high concentration of heteroatoms (N, S, Ni, V, etc.. Of the variety of techniques for heavy oil upgrading, supercritical water (SCW is gaining popularity because of its excellent ability to convert heavy oil into valued, clean light oil by the suppression of coke formation and the removal of heteroatoms. Based on the current status of this research around the world, heavy oil upgrading in SCW is summarized from three aspects: Transformation of hydrocarbons, suppression of coke, and removal of heteroatoms. In this work, the challenge and future development of the orientation of upgrading heavy oil in SCW are pointed out.

20% inlet header break analysis of Advanced Heavy Water Reactor

International Nuclear Information System (INIS)

Srivastava, A.; Gupta, S.K.; Venkat Raj, V.; Singh, R.; Iyer, K.

2001-01-01

The proposed Advanced Heavy Water Reactor (AHWR) is a 750 MWt vertical pressure tube type boiling light water cooled and heavy water moderated reactor. A passive design feature of this reactor is that the heat removal is achieved through natural circulation of primary coolant at all power levels, with no primary coolant pumps. Loss of coolant due to failure of inlet header results in depressurization of primary heat transport (PHT) system and containment pressure rise. Depressurization activates various protective and engineered safety systems like reactor trip, isolation condenser and advanced accumulator, limiting the consequences of the event. This paper discusses the thermal hydraulic transient analysis for evaluating the safety of the reactor, following 20% inlet header break using RELAP5/MOD3.2. For the analysis, the system is discretized appropriately to simulate possible flow reversal in one of the core paths during the transient. Various modeling aspects are discussed in this paper and predictions are made for different parameters like pressure, temperature, steam quality and flow in different parts of the Primary Heat Transport (PHT) system. Flow and energy discharges into the containment are also estimated for use in containment analysis. (author)

levels of heavy metals in gubi dam water bauchi, nigeria

African Journals Online (AJOL)

Ada

copper and lead were always highest in the suspended materials which indicate the dominant role played by ... essential. However, at high concentrations, these trace metals become toxic (Nurnberg, 1982). Heavy metals in .... mobilization of cobalt minerals into the dam. .... Interaction between sediments and fresh water ...

Satial and seasonal variations o heavy metals in water and sediment samles collected rom the Lower Danube River

Directory of Open Access Journals (Sweden)

IONESCU Petra

2016-12-01

Full Text Available Surface water pollution with heavy metals represents one of the most relevant environmental issues, with severe outcomes on every other environmental compartment, affecting therefore the human health because of their toxicity, persistence and bioaccumulation tendency. The Danube, one of the most important rivers of Europe considering its course, crossing the continent from west to east, represents the main collector of all pollutants emitted by the ten countries it passes through, prior to discharging into the Black Sea. Given all this, and because of the possible unwanted effects that may occur as a result of recent constructions taking place in the area to improve the navigation conditions, the aim of this study is to evaluate the variation of the global concentration of heavy metals in both water and sediments by calculating the Metal Pollution Index (MPI on the sector between Calarasi - Braila (km 370 - km 170. Water and sediment samples from Lower Danube were collected between January 2012 and December 2013, from ten different sites. The following heavy metals have been determined: chromium (Cr, copper (Cu, zinc (Zn, lead (Pb and nickel (Ni. Metal Pollution Index values were used for a seasonal and spatial comparison of the total metal content from the established sites. For a more detailed interpretation of results, Cluster Analysis was performed. Frequent monitoring of the heavy metal content of Lower Danube has a significant impact on water quality, keeping a low pollution risk and having a long term positive impact on environmental protection of the Black Sea Basin.

Determination of natural occurring radionuclide and heavy metals in drinking water in Malaysia

International Nuclear Information System (INIS)

Nur Suraya Ahmad

2012-01-01

The objective of this study is to ascertain the activity concentration of naturally occurring radionuclide and selected heavy metals selected mineral and drinking waters sample in Malaysia. The activity concentration of natural radionuclide (mBq/ L) was determined by Gamma Spectroscopy Systems while the concentration of heavy metal (mg/ L) was determined by the Induces Couple Plasma Mass Spectrometry (ICP-MS). The mineral and drinking water samples used in this study were Segar UKM, Giant, Ice Mountain (600 ml), Ice Mountain (1600 ml), Spritzer, Reverse Osmosis, and fresh tap water. The results of the study found 3 natural occurring radioactive materials (NORM) found for example - U-238, Ra-226 and Ra-228. The activity concentration determined was 0.00 mBq/ L to 1.71 mBq/ L for U-238, 0.00 - 32.46 mBq/ L for Ra-226 and 0.00 - 12.01 mBq/ L for Ra-228 respectively. The concentration of heavy metals Zn, Fe, As, Cl, Mn, Cu and Pb determined in this study were in the range of 0.000 - 0.003 mg/ L, 0.002-0.018 mg/ L, 0.000 - 0.007 mg/ L, 6.152 - 57.724 mg/ L, 0.000 - 0.016 μg/ L, 0.058 - 0.766 μg/ L and 0.000 - 0.380 μg/ L respectively. In general, the result of this study indicate that the activity concentration NORM and selected heavy metals in the studied mineral and drinking water samples were low and not exceed the limit set by World Organization (WHO) and Malaysian Food Regulations 1985. Thus, all the studied water samples complying the Malaysian drinking standard and safe to be consumed. (author)

[Research advances in heavy metals pollution ecology of diatom].

Science.gov (United States)

Ding, Teng-Da; Ni, Wan-Min; Zhang, Jian-Ying

2012-03-01

Diatom, due to its high sensitivity to environmental change, is one of the bio-indicators of aquatic ecosystem health, and some typical diatom species have been applied to indicate the heavy metals pollution of water body. With the focus on the surface water heavy metals pollution, this paper reviewed the research advances in the toxic effect of heavy metals pollution on diatom, biosorption and bioaccumulation of heavy metals by diatom, ecological adaptation mechanisms of diatom to heavy metals pollution, and roles of diatom as bio-indicator and in ecological restoration of heavy metals pollution. The growth tendency of diatom and the morphological change of frustule under heavy metals pollution as well as the differences in heavy metals biosorption and bioaccumulation by diatom, the ecological adaptation mechanisms of diatom on heavy metals surface complexation and ion exchange, and the roles of diatom as bio-indicator and in ecological restoration of heavy metals polluted water body were also discussed. This review could provide scientific evidences for the prevention of aquatic ecosystems heavy metals pollution and related early warning techniques.