International Nuclear Information System (INIS)

Finding environmentally friendly and cost-effective methods to remediate soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is currently a major concern of researchers. In this study, a series of small-scale semi-continuous extractions - with and without in situ wet oxidation - were performed on soils polluted with PAHs, using subcritical water (i.e. liquid water at high temperatures and pressures, but below the critical point) as the removal agent. Experiments were performed in a 300 mL reactor using an aged soil sample. To find the desorption isotherms and oxidation reaction rates, semi-continuous experiments with residence times of 1 and 2 h were performed using aged soil at 250 deg. C and hydrogen peroxide as oxidizing agent. In all combined extraction and oxidation flow experiments, PAHs in the remaining soil after the ...

International Nuclear Information System (INIS)

The condition of spent nuclear fuel (SNF) in wet storage at ten Soviet-designed research reactors has been assessed in the light of international experience in order to identify any associated safety issues. These reactors use Al-clad UO2-Al or U-Al alloy dispersion fuels of ?20% enrichment that were fabricated in Russia; the reactors have been in operation since 1955-70. Although originally sent for reprocessing, much of the SNF generated over the last 25-30 years has been stored in fuel storage pools (FSPs) of variable water quality. The external condition of wet-stored SNF assemblies from the reactors surveyed varied from significant failure due to galvanic corrosion that was driven by poor water quality, through gradual pitting caused by slightly impure water, to a stable condition of no observable change in the ...

International Nuclear Information System (INIS)

The development and successful application of a unique leak sealant formulation comprised of a mixture of graded, hollow ceramic microspheres, surface oxidized aluminum powder and saturated gibbsite suspension is described. The project was undertaken to address the escalating leakage from up to 15 small weld defects in the water reflector vessel, an integral component of the NRU (National Research Universal) reactor calandria. The reflector surrounds the reactor core with a neutron reflecting blanket of light water. Injection of the sealant is typically done with the reactor shutdown and the water reflector system operating normally, but can also be performed with the reactor at full power. The procedure is simple and effective. Individual treatments of as little as 125 ml of sealant (10 ppm in the 12,500 L system) have ...

International Nuclear Information System (INIS)

The present process allows to eliminate the corrosion products formed on the tube plates and in the interstices of plate-tube crosspieces of a PWR steam generator in order to avoid a corrosion phenomenon which may cause denting by presence of oxides. The process consists in applying on these oxides at about 50-100 degrees, an aqueous solution containing 6-8% of gluconic acid, 3-5% of citric acid, about 0.5% of a corrosion inhibitor and ammonia until a pH of 3-9.5 is obtained.

Energy Technology Data Exchange (ETDEWEB)

The verification test program on zinc injection applicability to Japanese BWRs was started in 1997. Laboratory tests using high temperature water loops under BWR reactor water conditions are in progress. This paper is an interim report on results obtained so far. Co-58 and Zn-65 were simultaneously used in the Co radioactivity buildup test to evaluate zinc injection suppression effects towards cobalt deposition on pre-oxidized stainless steel. The following results were obtained. The Co deposition was suppressed effectively by Zn injection, even when there was a pre-oxide film. For the test piping that had the pre-oxide film formed under the NWC (normal water chemistry) condition, when soaked under the HWC (hydrogen water chemistry) condition a large amount of Co-58 was taken into a small part of the inner layer. The ...

International Nuclear Information System (INIS)

The deposit of radioactive corrosion products in the cooling systems of nuclear reactors becomes a serious problem for the personnel of facilities. Crud has an important role in the process of depositing radioactive corrosion products. The main components of crud are hematite, magnetite, nickel ferrite and so on, and the particles of these oxide compounds are distributed in water. Most of the behavior of crud are still not known. As for the mechanism of the production of crud, the Potter-Mann model has been proposed. However, the precipitation process of iron ions in water is unknown. The crud is defined as the particles filtered by 0.45 micrometer millipore filters. However, it is not known whether there are crud particles smaller than this size. The crud particles can be adsorbed on the filters by the surface electrochemical interaction. The adsorption of cations to crud particles was studied. The ...

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The objective of this project was to develop new photocatalytic or other innovative process chemistry for the treatment of pink water and related contaminated water.

International Nuclear Information System (INIS)

The CERL Code was developed to describe the solution chemistry of the water on the steam generating side of PWR reactors. It is designed to calculate the equilibrium species distribution resulting from the interaction of impurities, corrosion products, and additives in the aqueous solution. It calculates the extent of ion-ion interactions, the precipitation of insoluble species and the amount of solute that partitions into the vapor phase when some of the water evaporates. This knowledge of the bulk phase equilibrium distribution of species, especially the pH should be useful in describing the corrosion processes at the solid liquid boundary. The code does not calculate any changes in oxidation states or any rates of reaction. Therefore, it is incapable of calculating the actual corrosion rates. It is anticipated that it will be used as a subprogram of a larger program that will include the redox ...

Energy Technology Data Exchange (ETDEWEB)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is ...

Energy Technology Data Exchange (ETDEWEB)

The emittance of aluminum components exposed to low-temperature aqueous solutions were required for thermal analysis of a Loss of Cooling Accident for the Savannah River Site production reactors. Experimental data for the thickness and emittance of oxide films formed under these conditions were collected and reviewed. Correlations were developed for the oxide film thickness and corresponding total hemispherical emittance. Film thickness and emittance were also measured for the specific conditions of interest in order to verify the predictions based on the literature data. After one year of exposure in 30deg C reactor moderator, the aluminum oxide film thickness is predicted to be 6.4 [mu]m[+-]10%; this value is relatively insensitive to exposure time. Some phenomena which would tend to yield thicker oxide films in the reactor environment ...

International Nuclear Information System (INIS)

Full text of publication follows: Slightly over-stoichiometric lithium orthosilicate pebbles have been selected as one optional breeder material for the European Helium Cooled Pebble Bed (HCPB) blanket. This material has been developed in collaboration of Research Center Karlsruhe and the Schott Glass, Mainz. The lithium orthosilicate pebbles are fabricated from lithium hydroxide and silica by a melting and spraying method in a semi-industrial scale facility. Lithium hydroxide was selected as the precursor since enriched lithium hydroxide is commercially available. The lithium orthosilicate pebbles produced by the process contains oxide phases besides orthosilicate, but it was also found that the oxide phases can be decomposed by annealing at high temperatures. The lithium orthosilicate pebbles produced in this way possesses satisfactory pebble characteristics. Therefore, the authors performed out-of-pile annealing tests using the lithium ...

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

For light water reactors, loss of coolant is an important point in safety analysis, whereas for gas-cooled reactors the ingress of water into the core region is an incident of safety relevance. The applicability of the computer code system GAMTEREX to pebble beds of spherical high-temperature gas-cooled reactor fuel elements with simulated water ingress is verified by experiment. The measurements were performed at a Siemens-Argonaut reactor, using its ring core as a driver zone for a pebble-bed core in the center of the reactor.

Energy Technology Data Exchange (ETDEWEB)

On-board reforming of liquid fuels to hydrogen for use in proton exchange membrane (PEM) fuel cell electric vehicles (FCEVs) has been the subject of numerous investigations. In many respects, liquid fuels represent a more attractive method of carrying hydrogen than compressed hydrogen itself, promising greater vehicle range, shorter refilling times, increased safety, and perhaps most importantly, utilization of the current fuel distribution infrastructure. The drawbacks of on-board reformers include their inherent complexity [for example a POX reactor includes: a fuel vaporizer, a reformer, water-gas shift reactors, a preferential oxidation (PROX) unit for CO cleanup, heat exchangers for thermal integration, sensors and controls, etc.], weight, and expense relative to compressed H{sub 2}, as well as degraded fuel cell performance due to the presence of inert gases and impurities in the reformate. ...

Energy Technology Data Exchange (ETDEWEB)

In this paper the diffusion of tritiated water vapor into concrete walls is studied to evaluate tritiated water retention capacity of a fusion reactor concrete building. Using a model of the tritiated water diffusion determined form experimental results, depth profiles of tritiated water in concrete are calculated in the case of being exposed to air containing tritiated water vapor during the normal operational condition of a fusion reactor. A 0.5-m-thick concrete is sufficient for reactor hall walls from a viewpoint of the tritium containment.

Energy Technology Data Exchange (ETDEWEB)

There is renewed interest in the development of natural gas vehicles in response to the challenge to reduce urban air pollution and consumption of petroleum. The natural gas/diesel dual fuel engine is one way to apply natural gas to the conventional diesel engine. Dual fuel engines operating on natural gas and diesel emit less nitrogen oxides, and less carbon soot to the air compared to conventional diesel engines. The problem is that at light loads, fuel efficiency is reduced and emissions of hydrocarbons and carbon monoxide are increased. This thesis focused on control methods for emissions of hydrocarbons and carbon monoxide in the dual fuel engine at light loads. This was done by developing a reverse flow catalytic converter to complement dual fuel engine exhaust characteristics. Experimental measurements and numerical simulations of reverse flow catalytic converters were conducted. Reverse flow creates a high reactor temperature even when ...

International Nuclear Information System (INIS)

Recent nuclear power plants require high purity water to protect nuclear reactors or steam generators from SCC and maintain in good condition. In this connection, it is especially important to minimize sulfate, which is a corrosive chemical originated from oxidative degradation of cation exchange resins during operation. Recently, uniform particle size (UPS) strong acid cation gel resin with 14% cross-linkage, which has excellent stability against oxidization, has been applied to several condensate purification systems. For further improvement of water quality, some methods for changing the configuration of condensate demineralizer's resin bed have been examined. For example, these methods correspond to anion under layer and cation over layer. We have tested these methods by cold column tests. Furthermore, we have developed the newly anion exchange resin having higher efficiency and ...

Energy Technology Data Exchange (ETDEWEB)

Chemical oxidation is a treatment technology that uses powertul chemical oxidizers to destroy organic contaminants. Typical oxidizers used in chemical oxidation processes include ozone, hydrogen peroxide, chlorine, and potassium permanganate. The chemical reaction products are usually simple organic compounds, such as carboxylic acids, and/or inorganic compounds, such as carbon dioxide, water, and simple inorganic complexes (e.g., chloride salts, in the case of chemical oxidation treatment of chlorinated solvents).

International Nuclear Information System (INIS)

Object: To limit the discharge amount of reactor water in a primary system at the time of scram to prevent excessive outflow of reactor water outside the system. Structure: A signal from an upper limit position indicator detects the fact that control rods are completely inserted when the reactor is urgently stopped and the detection signal causes a valve in an outflow line of the discharge water from a control rod driving mechanism to be closed to limit the amount of discharge flown into the scram discharge vessel, thus preventing outflow of reactor water in the primary system after the scram has been initiated. (Kamimura, M.).

International Nuclear Information System (INIS)

Purpose: To stably control the reactor water level so as not to cause excess water feeding in a BWR type reactor. Constitution: A flow control valve is disposed to the exit of a feedwater pump for a nuclear reactor and the valve is controlled by a flow regulator to maintain the water level constant in the reactor. A signal from a water level controller is inputted to the flow regulator to thereby control the flow rate control valve. In this case, the flow regulator remains in a saturated state just after the starting of the feedwater pump, in which the pump flowrate is at 100% to result in an excess water feeding condition. In view of the above, a feedback circuit is provided to the flow regulator so that the saturated state is eliminated and the water feeding can be controlled ...

Energy Technology Data Exchange (ETDEWEB)

We report on the fouling of Focused Ion Beam (FIB)-fabricated silicon oxide nanopores after exposure to tap water for two weeks. Pore clogging was monitored by Scanning Electron Microscopy (SEM) on both bare silicon oxide and chemically functionalized nanopores. While fouling occurred on hydrophilic silicon oxide pore walls, the hydrophobic nature of alkane chains prevented clogging on the chemically functionalized pore walls. These results have implications for nanopore sensing platform design.

Energy Technology Data Exchange (ETDEWEB)

In recent years, the influences of acid rain such as the acidification of lake water, on bio-system by the heavy metals from effluent of soils with acid rain and also on the structural materials of buildings are seriously discussed. Sulfur and nitrogen that are contained in fossil fuels are released into the atmosphere by the fuel combustion as their oxides dissolve in rain drops as sulfite and nitrous ions, where they are further oxidized into sulfate and nitrate ions These ions lower the pH of rain water resulting so-called acid rain. Therefore, it is important to accurately determine these ions in rain water for the investigation of reality of acid rain. However, it is not easy to accurately determine these ions, especially for sulfite ions in rain water, since they are quickly oxidized by the catalytic action of metallic ions such as ...

Energy Technology Data Exchange (ETDEWEB)

THe high-temperature reactor is one of the alternatives for the now predominantly employed water-reactors. In a recently published book designer Rudolf Schulten outlines his concept. In this article the book is reviewed. (author). 1 ref.; 1 fig.

International Nuclear Information System (INIS)

Cooling water is sprayed on the outer surface of an upper portion of a container, and a pool is formed by the cooling water flowing down while cooling the container. Further, the cooling water stored in the cooling water pool is recycled by a pump for spraying the cooling water on the outer surface of the upper portion of the container. Sufficient amount of cooling water is supplied for spraying the cooling water to the outer surface of the upper portion of the container so that the outer surface of the container is free from drying and a liquid membrane is formed on the entire surface. The amount of the cooling water is made greater than that of the cooling water evaporated when the entire amount of the heat generate in the reactor core of the reactor is ...

International Nuclear Information System (INIS)

Division of Remote Handling and Robotics (DRHR) at Bhabha Atomic Research Centre (BARC) has been working on design and development of Reactivity Control Mechanisms for Nuclear Research Reactors (Dhruva, KAMINI and recently Critical Facility of Advanced Heavy Water Reactor (AHWR)) as well as Power Reactors in India (Pressurized Heavy Water Reactors of 220 MWe at Narora and recently India's first 540 MWe PHWR Unit -1 and 2 at Tarapur). This paper gives a brief account of evolution of reactivity control mechanisms for nuclear research and power reactors in India. (author)

International Nuclear Information System (INIS)

... 2432 v. 43(1) SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS

Energy Technology Data Exchange (ETDEWEB)

This article gives an account of the recent development of light water reactors new concepts in the world. Different projects are being studied. The CE80+ from Combustion Engineering (CE) is a 1350 MWe-PWR-type reactor whose primary circuit is confined in a spherical metallic containment. This reactor was certified by NRC (national regulatory commission) in mid-1996. The APWR (advanced pressurized water reactor) is developed by MHI (Mitsubishi heavy industries) in a collaboration with Westinghouse, this PWR-type reactor fitted with 4 loops derived from the SP90 model that was developed by Westinghouse during the eighties. 2 units of ABWR (advanced boiling water reactor) were commissioned in Japan in 1996 and 1997, ABWR was certified by NRC in mid-1996. The BWR90+ is developed by ABB-atom (Sweden) and ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of the conversion process is to convert the {sup 233}U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019.

International Nuclear Information System (INIS)

Object: To smoothly control automatic water supply for realizing stable operation of a nuclear reactor by providing a flow rate limiting signal selection circuit and a preferential circuit in a water supply control device for a nuclear reactor wherein the speed of a recirculation pump may be changed in two-steps. Structure: Opening angle signals for a water supply regulating valve are controlled by a nuclear reactor water level signal, a vapor flow rate signal and a supplied water flow rate signal through an adder and an adjuster in response to a predetermined water level setting signal. When the water in the reactor is maintained at a predetermined level, a selection circuit receives a water pump condition signal for selecting one of the ...

Energy Technology Data Exchange (ETDEWEB)

Individual monitoring of personal exposure to inhalation of uranium oxides throughout the manufacture of fuel for pressurized water reactor (PWR) includes lung gamma-spectrometry, fecal analysis and urine analysis. Examination of the results shows the following: internal exposure is the consequence of repeated intake incidents as revealed by early peaks of urinary and particularly fecal elimination; a shift is often observed with the results of aerosol concentration measured through air collectors; the measured variations of uranium lung incorporations are relatively fast (apparent mean period 165 d). Correct evaluation of the effective dose equivalent from inhalation requires further information concerning the aerosol size distribution at work stations, the physico-chemical characteristics of the product leading to an estimate of its actual biological solubility, and the measurement of the fraction of aerosol liable to ...

Energy Technology Data Exchange (ETDEWEB)

The steam generator low water level trip setpoint of KORI NPP units 3 and 4(KNU 3 and 4), three-loop Westinghouse pressurized water reactor, is higher than that of OPR1000. In addition, steam generator downcomer water level in KNU 3 and 4 could fluctuate easily during a transient because of smaller downcomer water inventory, compared to the total water inventory in the steam generator. Due to these reasons, there is a higher possibility of unnecessary reactor trips caused by the steam generator low-low water level in KNU 3 and 4. Its operating history shows that most of reactor trips were caused by steam generator low-low level reactor trip signal. Such reactor trips, especially unnecessary ones, result in time and economic losses. In this paper, a ...

Energy Technology Data Exchange (ETDEWEB)

General corrosion behavior of ALLOY 800 in high temperature water was studied in relation to its surface film structure. The surface film formed in water was found to decrease the corrosion rate of ALLOY 800. This film is composed of Ni ferrite, and can be obtained by oxidation in air or steam. Based on these results, air or steam oxidation treatment to inhibit Ni and Co release of ALLOY 800 into high temperature water is proposed. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper reports on hydrolysis of 10 metal salt aqueous solutions of 6 metal oxides that was conducted in supercritical water. Continuous and rapid production of metal oxide fine particles was achieved by mixing a metal salt aqueous solution with preheated water fed from another line. The reaction time required was less than 2 min. Particle size, morphology, and crystal structure of the obtained metal (hydrous) oxides were examined. Particle size (20 to 600 nm) was different among the system but the size range was relatively narrow in all the cases.

International Nuclear Information System (INIS)

The TVR heavy water research reactor was deployed at Moscow Institute of Theoretical and Experimental Physics. In 1990, the final batch of the spent nuclear fuel from this reactor was shipped to Production Association (PA) 'Mayak' for reprocessing. The SNF removal was a stage of the reactor decommissioning activities. The designs of the TVR reactor and its fuel elements are similar to the RA reactor designs. Two ways of the RA reactor SNF transportation to PA 'Mayak' have been considered: in aluminum barrels and in additional canisters using respectively TUK-32 and TUK-19 shipping casks. The practical experience and the equipment used to prepare for the TVR reactor SNF removal can be helpful to the RA reactor personnel in finding the best way to perform these engineering operations. (author)

International Nuclear Information System (INIS)

Presently, industrial maturity can be claimed for two fuel cycle strategies, viz. the 'Once Through Fuel Cycle' (OTC), and the 'Reprocessing Fuel Cycle' (RFC) in which plutonium and very limited uranium quantities are being recycled. It is helpful to recall some key data that set the stage for any discussion of fuel cycle options: 1. Worldwide, the annual spent fuel discharge is in the range of 10500-11000 t heavy-metal (HM), while the industrial reprocessing capacity amounts to #approx# 5000 t HM (OECD NUCLEAR ENERGY AGENCY, Accelerator-driven Systems (ADS) and Fast Reactors (FR) in Advanced Nuclear Fuel Cycles: a Comparative Study, Paris, 2002). Hence, less than 1/2 of the discharged spent fuel can be processed. 2. Worldwide, the cumulative inventory of stored spent fuel is estimated to be #approx# 190000 t HM, and the amount of reprocessed spent fuel is estimated to be #approx# 70000 t HM. The latter inventory has been transformed into high-level waste (HLW) and ...

Energy Technology Data Exchange (ETDEWEB)

The addition of ZnO, depleted in the Zn-64 isotope, to the water of boiling water nuclear reactors lessens the accumulation of Co-60 on the reactor interior surfaces, reduces radioactive wastes and increases the reactor service-life because of the inhibitory action of zinc on inter-granular stress corrosion cracking. To the same effect depleted zinc in the form of acetate dihydrate is used in pressurized water reactors. Gas centrifuge isotope separation method is applied for production of depleted zinc on the industrial scale. More than 20 years of depleted zinc application history demonstrates its benefits for reduction of NPP personnel radiation exposure and combating construction materials corrosion.

International Nuclear Information System (INIS)

This paper discusses the remote plugging of leaks in inaccessible pipework, with main reference to small leaks which frequently appear in ancillary cooling water circuits of nuclear reactors. Initially developed to cure problems of the pre-stressed concrete pressure vessels of UK reactors, the ZORIC sealant has been used to repair leaking biological shield pipework on six CANDU reactors. ZORIC is based on a water-soluble epoxy resin and an aqueous suspension of a refined mineral clay. This paper describes the evolution of the sealant, the qualification and testing program, and their application to CANDU reactor systems. 2 refs., 6 figs.

Energy Technology Data Exchange (ETDEWEB)

The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are unusually rapid.

International Nuclear Information System (INIS)

The heavy water reactor such as Wolsung No.1 and No.2 has a purification system to purify the reactor coolant. The control system regulates the coolant temperature to protect the ion exchanger. After the fuel exchanges of operating plant, the increase of the coolant pressure makes the purification temperature control difficult. In this paper, the controllability of the control dynamics of the purification system was analysed and the optimal parameters were proposed. To reduce the effects of the flow disturbance, the feedforward control structure was proposed and analysed.

Science.gov (United States)

The growth of an oxide interfacial layer was recently found to increase the open-circuit voltage (OCV) and efficiency by up to 60 per cent in GaAs metal-semiconductor solar cells. Details of oxidation techniques to provide the necessary oxide thickness and chemical structure and using ozone, water-vapor-saturated oxygen, or oxygen gas discharges are described, as well as apparent crystallographic orientation effects. Preliminary results of the oxide chemistry obtained from X-ray, photoelectron spectroscopy are given. Ratios of arsenic oxide to gallium oxide of unity or less seem to be preferable. Samples with the highest OVC predominantly have As(+3) in the arsenic oxide rather than As(+5). A major difficulty at this time is a reduction in OCV by 100-200 mV when the antireflection coating is vacuum deposited.

Energy Technology Data Exchange (ETDEWEB)

A summary of the off-gas behavior in the HARVEST pot vitrification process is presented. Experimental runs were carried out on 3 representative wastes (MAGNOX - thermal reactor, metal fuel, THORP - thermal oxide fuel and PFR - fast reactor oxide fuel) using 2 methods of feeding the glass-formers (slurry and crizzle). Materials were carried over from the vitrification vessel into the off-gas system by entrainment supplemented by volatilization. The main volatile elements were Ru, B, Cs. Some volatility was also shown by Na and Li. The overall behavior of the off-gas was consistent with the presence in it of 5 separate aerosols of particulate matter. Sources of entrainment gave rise to 3 aerosols, and a further 2 aerosols were formed as a result of chemical reaction (Ru) and condensation (Cs) proceses involving the volatile species. Entrainment was enhanced when the feed contained free alkali nitrate. The ...

Science.gov (United States)

(accumulates & stores brine for disposal). Separator. (separates water from purge gases). ? Purge pump periodically vent ... Reactor Health. Sensor. ( verifies reactor is operating w/n limits) ... Waste and Hygiene Compartment ...

International Nuclear Information System (INIS)

... Sergio Department of Materials, University of Oxford, Oxford (United Kingdom)

Energy Technology Data Exchange (ETDEWEB)

This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors from January 1997 to June 1997. Topics that have been investigated include (a) fatigue of carbon, low-alloy, and austenitic stainless steels (SSs) used in reactor piping and pressure vessels, (b) irradiation-assisted stress corrosion cracking of Types 304 and 304L SS, and (c) EAC of Alloys 600 and 690. Fatigue tests were conducted on ferritic and austenitic SSs in water that contained various concentrations of dissolved oxygen (DO) to determine whether a slow strain rate applied during various portions of a tensile-loading cycle is equally effective in decreasing fatigue life. Slow-strain-rate-tensile tests were conducted in simulated boiling water reactor (BWR) water at 288 C on SS specimens ...

Energy Technology Data Exchange (ETDEWEB)

The oxidative dehydrodimerization of propylene to C/sub 3/-dimers (1,5-hexadiene and benzene) has been examined at 600/sup 0/C and atmospheric pressure using a (Bi/sub 2/O/sub 3/)/sub 0.85/(La/sub 2/O/sub 3/)/sub 0.15/ oxide ion-conducting catalyst in a reactor where a catalyst disk separates a feed of propylene in helium from air. The surface of the disk exposed to propylene was reoxidized not by gaseous O/sub 2/, but by the dissociative adsorption and reduction of dioxygen at the oxidant side of the disk, followed by oxide ion conduction to replace spent lattice oxygen. Selectivity to C/sub 3/-dimers when using lattice oxide migration to reoxidize the catalyst was considerably greater than when O/sub 2/ was added to the propylene feed under the same reaction conditions. This result supports the proposal that lattice oxygen is predominantly involved in the ...

Science.gov (United States)

developing a consensus PRA standard for non- associated guidance light water reactor applications that will address some aspects of PRA in design. ...

Energy Technology Data Exchange (ETDEWEB)

The effect of sodium on the partial oxidation of methane over MoO{sub 3}-SiO{sub 2} in the presence of molecular oxygen has been investigated. As in the sodium-free case, the major products are formaldehyde, carbon monoxide, carbon dioxide, and water. Kinetic analysis indicates that methane is directly oxidized to formaldehyde and carbon dioxide. Formaldehyde is oxidized to carbon monoxide, which is itself further oxidized, providing an alternative route to carbon dioxide. The kinetic model shows that sodium poisons the direct oxidation of methane to formaldehyde and carbon dioxide, but promotes the oxidation of formaldehyde and carbon monoxide. Model predictions of rates and selectivities are in good agreement with the experimental data. A mechanism that explains both the poisoning and promotion effects of sodium on MoO{sub 3}-SiO{sub 2} is ...

International Nuclear Information System (INIS)

This paper examines the attractiveness of material mixtures containing special nuclear materials (SNM) associated with reprocessing and the thorium-based LWR fuel cycle. This paper expands upon the results from earlier studies that examined the attractiveness of SNM associated with the reprocessing of spent light water reactor (LWR) fuel by various reprocessing schemes and the recycle of plutonium as a mixed oxide (MOX) fuel in LWR. This study shows that "2"3"3U that is produced in thorium-based fuel cycles is very attractive for weapons use. Consistent with other studies, these results also show that all fuel cycles examined to date need to be rigorously safeguarded and provided moderate to high levels of physical protection. These studies were performed at the request of the United States Department of Energy (DOE), and are based on the calculation of 'attractiveness levels' that has been couched in terms chosen for ...

International Nuclear Information System (INIS)

The alpha emitter plutonium-238 ("2"3"8Pu), which is produced in uranium-fueled, light-water reactors, is used as a thermoelectric power source for space applications. Inhalation of a mixed oxide form of Pu is the most likely mode of exposure of workers and the general public. Occupational exposures to "2"3"8PuO_2 have occurred in association with the fabrication of radioisotope thermoelectric generators. Organs and tissue at risk for deterministic and stochastic effects of "2"3"8Pu-alpha irradiation include the lung, liver, skeleton, and lymphatic tissue. Little has been reported about the effects of inhaled "2"3"8PuO_2 on peripheral blood cell counts in humans. The purpose of this study was to investigate hematological responses after a single inhalation exposure of Beagle dogs to alpha-emitting "2"3"8PuO_2 particles and to extrapolate results to humans.

International Nuclear Information System (INIS)

Organic waste, as a main constituent of municipal solid waste, has as well as solid biomass a high potential for biogas generation. Despite the importance of biogas generation from these materials, the availability of large-scale biogas processes lacks behind the demand. A newly developed double-stage solid-liquid biogas process, consisting of an open hydrolysis stage and a fixed-bed methane reactor, allows the biogas production from almost all biodegradable solid waste and renewable resources like maize, grass, sugar cane, etc. Furthermore, residues from industrial processes, like the glycerine waste water from biodiesel production, can also be converted into biogas successfully. Due to the strong separation of hydrolysis and methanation, the process is extremely stable. No malfunction has been detected so far. The open hydrolysis releases CO_2 and allows oxidation of sulfur. Consequently, the biogas has a high methane ...

Energy Technology Data Exchange (ETDEWEB)

Chemical looping combustion is a novel technology that can be used to meet the demand on energy production without CO{sub 2} emission. To improve CO{sub 2} capture efficiency in the process of chemical looping combustion of coal, a prototype configuration for chemical looping combustion of coal is made in this study. It comprises a fast fluidized bed as an air reactor, a cyclone, a spout-fluid bed as a fuel reactor and a loop-seal. The loop-seal connects the spout-fluid bed with the fast fluidized bed and is fluidized by steam to prevent the contamination of the flue gas between the two reactors. The performance of chemical looping combustion of coal is experimentally investigated with a NiO/Al{sub 2}O{sub 3} oxygen carrier in a 1 kW{sub th} prototype. The experimental results show that the configuration can minimize the amount of residual char entering into the air reactor from the fuel ...

International Nuclear Information System (INIS)

The following methods of quartz ceramics alloying were considered: alloying of initial quartz glass; introduction of alloying additive into water slip of quartz glass; porous materials impregnation with salt aqueous solutions and subsequent salt thermal decomposition with formation of stable oxides in pores of ceramics. Oxygen free compounds BN, SiB_4, SiC, Si_3N_4, REM oxides and transition metal oxides were used as alloying additives. Main properties of the materials and compositions obtained are presented.

International Nuclear Information System (INIS)

Dr. Rudolf Schulten of West Germany and expert witnesses from national laboratories, utilities, and the nuclear industry testified on reactor safety issues as they relate to the Chernobyl accident and public concern that modern technology has not paid enough attention to public safety. Each of the witnesses contributed safety-related information based on what has been learned from the Soviet incident. Particular focus went to similarities and differences between the Chernobyl and US reactors in safety design and engineering and to the environmental effects of the accident. The N reactor near Richland and a commercial reactor at Fort St. Vrain, Colorado are the only two operating graphite reactors, but neither is a boiling water reactor.

Energy Technology Data Exchange (ETDEWEB)

The paper gives an overview on the technologies and applications of automatic wood furnaces. The combustion systems are defined by the flow condition: With increasing gas velocity, fixed bed, stationary fluidized bed (SFB), circulating fluidized bed (CFB), and entrained flow reactors are distinguished. The furnace design and typical applications are described. Further, a comparison is presented which gives data of the typical size range and fuel types for the different combustion systems. The most common fixed bed reactors are under-stoker and grate furnaces. While under-stoker furnaces are applied in the size range from 20 kW to 2.5 MW, grate furnaces cover the size range from a few 100 kW up to more than 50 MW. Under-stoker furnaces are well suited for wood fuel with low ash content, moderate water content and limited fuel size. Grate furnaces are also suited for fuel with high ash and water content ...

Energy Technology Data Exchange (ETDEWEB)

This is the sixth book on reactor materials published under sponsorship of the Naval Reactors Office of the United States Department of Energy, formerly the United States Atomic Energy Commission. This book presents a comprehensive compilation of the most significant properties of thorium dioxide, much like the book Uranium Dioxide: Properties and Nuclear Applications presented information on the fuel material used in the Shippingport Pressurized Water Reactor core.

International Nuclear Information System (INIS)

The concept of preliminary transmutation of minor actinides before placement to the long-term storage is considered. The purpose of such preliminary transmutation before ultimate storage is to incinerate a part of actinides and to transform another part into new actinides providing low level of radiotoxicity accumulated in the storage. Modes of transmutation in reactors of PWR, PHWR (CANDU), and Superfenix types are compared. Among power reactors, heavy-water PHWR type reactor is most acceptable for preliminary transmutation. (author)

International Nuclear Information System (INIS)

Manganese is a common contaminant of mine water and other waste waters. Due to its high solubility over a wide pH range, it is notoriously difficult to remove from contaminated waters. Previous systems that effectively remove Mn from mine waters have involved oxidising the soluble Mn(II) species at an elevated pH using substrates such as limestone and dolomites. However it is currently unclear what effect the substrate type has upon abiotic Mn removal compared to biotic removal by in situ micro-organisms (biofilms). In order to investigate the relationship between substrate type, Mn precipitation and the biofilm community, net-alkaline Mn-contaminated mine water was treated in reactors containing one of the pure materials: dolomite, limestone, magnesite and quartzite. Mine water chemistry and Mn removal rates were monitored over a 3-month ...

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This report discusses a desk-top computer program has been developed for estimating the costs, waste volumes, and occupational radiation exposures associated with decommissioning light-water reactor power stations. Cost categories and cost algorithms used in the program are discussed and a brief description of the user interface is given.

International Nuclear Information System (INIS)

Purpose: To eliminate the water level deviation due to the recycling flowrate, as well as enable a stable control to a reference value even upon changes in the recycling flowrate caused by the variation in the opening degree of a minimum flow valve. Constitution: Reactor recycling system comprises a feedwater pump, a flowrate control valve, a reactor water level detector, and a minimum flow line and a minimum flow valve for preventing the overheating of the feedwater pump at a low flowrate. A flowrate compensator is further disposed, in which a recycling flowrate signal is subtracted from a pump flow rate signal and the result is fedback as a compensated pump flowrate signal. This enables the control system to operate at a rapid response for suppressing the effect of the recycling flowrate as external disturbance, whereby the water level in the reactor can be ...

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A highly reliable control rod drive mechanism (CRDM) installed inside the reactor vessel has developed for use of an advanced marine reactor. This CRDM contributes to compactness and simplicity of the reactor system, and it can eliminate the possibility of a rod ejection accident. The CRDM works in the high temperature and high pressure water - 310degC and 12 MPa, the same atmosphere as the primary loop. Driving force is produced by a synchronous motor with the rotor of a permanent magnet, which has been developed. An innovative latch mechanism using separable ball nuts can latch driving shaft connecting the control rod and de-latch it for scram. The rod position detector using a magnetostrictive wire type sensor on the principle of Wiedeman effect has been developed, accuracy of which is verified to have a detecting error within 1.2 mm. Ball bearings for thrust and radial supports in rotation have been ...

International Nuclear Information System (INIS)

An improved coating for Advanced Gas Cooled Nuclear Reactor austenitic stainless steel fuel cans is described which, tests have shown, inhibits the deposition of carbon on the cans in carbon-containing ionising radiation environments. The coating comprises a refractory oxide which has been prepared by a vapour phase condensation method, in combination with a noble metal. (U.K.).

International Nuclear Information System (INIS)

Active Process Water (APW) System, provided as unitized closed loop system in Tarapur Atomic Power Project Units-3 and 4, serves to remove heat from various heat exchangers. One of the important loads served by APW system is shutdown cooling heat exchangers and if APW shutdown is taken then reactor cannot be maintained in cold shutdown condition. It is estimated that after 7 days of reactor shutdown, if about 20% of the normal cooling flow to shutdown cooling heat exchangers is provided then along with keeping PHT in cold shutdown state, reactor components, moderator, end shield water, calandria vault water and calandria vault concrete temperature can be maintained within technical specification limits for extended duration. (author)

International Nuclear Information System (INIS)

Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to "6"0Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with "6"0Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and ...

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This paper addresses fuel cycle cost comparisons for a generic 10 MW reactor with HEU aluminide fuel and with LEU oxide and silicide fuels in several fuel element geometries. The intention of this study is to provide a consistent assessment of various design options from a cost point of view. Fuel cycle cost benefits could result if a number of reactors were to utilize fuel elements with the same number or different numbers of the same standard fuel plate. Data are presented to quantify these potential cost benefits. This analysis shows that there are a number of fuel element designs using LEU oxide or silicide fuels that have either the same or lower total fuel cycle costs than the HEU design. Use of these fuels with the uranium densities considered requires that they are successfully demonstrated and licensed.

Energy Technology Data Exchange (ETDEWEB)

The calculated radioactive waste inventories of the Turkey Point pressurized water fission reactor (PWR) and the Starfire conceptual fusion tokamak are compared as a function of time from initial start-up to 10,000 years after decommissioning. Only material out of reactor at least one year is considered. The total activity in Ci/W(th) of the Starfire tokamak is slightly greater than that of the PWR during the active lifetimes of the two reactors and beyond 1000 years. However, using reduced activation materials in Starfire can result in about 1/2000 as much long-lived radioactivity as in the fission reactor. It is stressed that comparison of wastes on this basis is not straightforward, since the radioisotopes and methods required for their disposal are different for fusion and fission reactors. 2 refs., 1 fig., 2 tabs.

International Nuclear Information System (INIS)

Surface study techniques were used to investigate films on Type 304 stainless steel which were formed during exposure to high purity water at 288"0C. The results indicated that the film chemistry depended strongly upon the concentration of the dissolved O_2 in the water. Films formed in water having 8 ppm O_2 were stoichiometric mixed oxides; whereas those formed in water with 10 ppb O_2 were highly defective oxyhydroxides. The latter films are not as protective as the stoichiometric oxides. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to investigate the films. (Auth.).

International Nuclear Information System (INIS)

In an existent emergency reactor core cooling device, if a ruptures should occure in a pipeline of a gravitational dropping type reactor core cooling system pool (GDCS) due to some or other causes, a portion of GDCS pool water was flown out of the ruptured port and could not be used for reactor core cooling. Then, a difference pressure detector is disposed to a GDCS pipeline at the inlet of a reactor pressure vessel. When it is judged by the detector, that coolants flow to the outside of the injection pipeline, an injection value disposed to the GDCS pipeline is closed by the difference pressure signal. Even if a rupture should occur on the side of the pressure vessel at downstream to the check value of the GDCS pipeline, since backflow is caused at the pressure container inlet of the GDCS pipeline with the rupture port, the rupture is detected by the difference pressure detector to ...

British Library Electronic Table of Contents (United Kingdom)

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer suffered the sol-gel reaction under alkaline conditions in the presence of titanium oxide nanoparticles in tetrahydrofuran to afford the corresponding fluorinated oligomer/titanium oxide nanocomposites[RF-(VM-SiO2)n-RF/TiO2] in excellent to moderate isolated yields. These fluorinated composites thus obtained were nanometer size-controlled fine particles, and exhibited good dispersibility and stability in traditional organic solvents except for water. These fluorinated nanocomposites were applied to the surface modification of glass to exhibit not only a completely superhydrophobic characteristic (a water contact angle: 180degree) with a non-wetting property against water droplets but also a good oleophobicity imparted by fluoroalkyl seg...

British Library Electronic Table of Contents (United Kingdom)

An experimental investigation on the air/water counter-current two-phase flow in a horizontal rectangular channel connected to an inclined riser has been conducted. This test-section representing a model of the hot leg of a pressurized water reactor is mounted between two separators in a pressurized experimental vessel. The cross-section and length of the horizontal part of the test-section are (0.25mx0.05m) and 2.59m, respectively, whereas the inclination angle of the riser is 50degree. The flow was captured by a high-speed camera in the bended region of the hot leg, delivering a detailed view of the stratified interface as well as of dispersed structures like bubbles and droplets. Countercurrent flow limitation (CCFL), or the onset of flooding, was found by analyzing the water levels mea...

International Nuclear Information System (INIS)

Three copper-based alloys, CDA 102 (oxygen-free, high-purity copper), CDA 613 (aluminum bronze), and CDA 715 (Cu-30Ni), are candidates for the fabrication of high-level radioactive-waste disposal containers. Waste will include spent fuel assemblies from reactors as well as borosilicate glass, and will be sent to the prospective repository site at Yucca Mountain in Nye County, Nevada. The decay of radionuclides will result in the generation of substantial heat and in fluxes of gamma radiation outside the containers. In this environment, container materials might degrade by atmospheric oxidation, general aqueous phase corrosion, localized corrosion (LC), and stress corrosion cracking (SCC). This volume is a critical survey of available data on pitting and crevice corrosion of the copper-based candidates. Pitting and crevice corrosion are two of the most common forms of LC of these materials. Data on the SCC of these alloys is surveyed in Volume ...

International Nuclear Information System (INIS)

This paper describes Automatic Refueling Planning System (ARPS) for a nuclear power station using Genetic Algorithms (GA) and a Simulated Annealing (SA). ARPS has been developed and verified by applying to the Fugen nuclear power station (NPS), which is a 165MWe, heavy water-moderated, boiling light water-cooled, pressure tube-type reactor developed by JNC utilizing mainly uranium and plutonium mixed oxide (MOX) fuel. Fuel loading patterns have been managed independently in the Fugen NPS since the initial core. A planning of an adequate fuel loading pattern on each operational cycle needs one to two months even for expert core management engineers, for the reason that it has multi-objective optimization and nonlinear problems. In order to achieve the optimum fuel loading pattern and a fuel cost reduction, ARPS has been developed by JNC and CRC Solutions Corporation for the last five years. ARPS firstly ...

International Nuclear Information System (INIS)

Tarapur Atomic Power Station unit-4 is first 540 MWe pressurized heavy water reactor. Heavy water is used as the coolant and moderator. With reactor operation tritium is formed by absorption of neutron by Deuterium atoms. Experience in the 220 MWe indicates that tritium is main contributor to the internal dose of radiation workers. Study on Tritium build up in Primary Heat Transport (PHT) and Moderator (MOD) system was carried out at the initial stage of the operation of the unit-3 and 4. This paper brings out tritium activity buildup in the PHT and MOD systems and its comparison with 220 MWe reactors. This paper helps in estimation of the internal dose contribution to the radiation workers at TAPS 3 and 4. (author)

Science.gov (United States)

An optimal deployment pattern of flux mapping detectors for a Canada uranium-deuterium (CANDU)-600 pressurized heavy water reactor (PHWR) is determined by obtaining an optimal feedback relationship between flux measurements and zone controllers. The reactor core is modeled with a time-dependent two-group, two-dimensional diffusion equation, and flux perturbation are expressed by model expansions. The modal expansion coefficients are used as elements of the state vector representing the system dynamics. An optimal feedback matrix connecting the flux measurement vector to the control vector is derived by minimizing a quadratic performance index involving both the state and control vectors. We obtain the detector effectiveness in terms of the optimal feedback matrix and determine optimal detector locations for the Wolsung Unit 1 reactor in Korea. We have tested the methodology through evaluation of flux ...

British Library Electronic Table of Contents (United Kingdom)

The oxidation of n-butylbenzene was studied in a jet-stirred reactor (JSR) at 10atm in dilute conditions providing new experimental results over the low- and high-temperature range 550-1180K, and variable equivalence ratio (0.25ϕ1.5). They consisted of concentration profiles of the reactants, stable intermediates and final products, measured as a function of temperature, at a constant residence time of 1s, by sonic probe sampling followed by on-line GC-MS and off-line GC-TCD-FID and GC-MS analyses. The oxidation of n-butylbenzene in these conditions was modeled using a detailed chemical kinetic reaction mechanism (404 species and 2210 reactions, most of them reversible) deriving from a previous scheme proposed for the ignition, oxidation, and combustion of simple aromatics (benzene,...

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Pulse reactor experiments were conducted on the reactions of unlabeled or deuterium- or oxygen-18-labeled allyl alcohols over molybdenum trioxide and various bismuth molybdates in the absence or presence of oxygen and ammonia. The allyl alcohol apparently adsorbed on oxidation sites to form acrolein via allyl molybdates, and on Broensted acid sites to form diallyl ether via an allyl carbonium ion. The bismuth enhanced ..cap alpha..-hydrogen abstraction, which was the rate-determining step in the oxidation. The product distributions provided evidence that the selective oxidation of propylene to acrolein proceeds via a m-allyl molybdate which collapses to an O o-allyl molybdate prior to the second hydrogen abstraction, and that the analogous N o-complex in ammoxidation undergoes two hydrogen abstractions to form acrylonitrile. Detailed reaction schemes are developed.

UK PubMed Central (United Kingdom)

The resistance to destruction of spores of Bacillus subtilis var. niger occluded in crystals of calcium carbonate and exposed to ethylene oxide and moist and dry heat...Full Text Available

International Nuclear Information System (INIS)

The Advanced MAPLE is a research reactor design under development as a high-flux neutron source. The main performance goals for the reactor are a high peak thermal neutron flux in a heavy-water reflector tank, and a high average fast neutron flux in a central irradiation facility, with a maximum linear fuel rod rating of less than 120 kW/m. This study investigated the neutronic and reactor design consequences of the use of H_2O coolant as opposed to D_2O. The neutronics results, and several other considerations, indicate that H_2O coolant has a number of advantages. It is suggested that the H_2O coolant option be considered in the design of the Advanced MAPLE reactor. (L.L.) 9 refs., 4 figs., tab.

Science.gov (United States)

Lanthanide-ion doped oxide nanoparticles were functionalized for use as fluorescent biological labels. These nanoparticles are synthesized directly in water which facilitates their functionalization, and are very photostable without emission intermittency. Nanoparticles functionalized with guanidinium groups act as artificial toxins and specifically target sodium channels. They are individually detectable in cardiac myocytes, revealing a heterogeneous distribution of sodium channels. Functionalized oxide nanoparticles appear as a novel tool particularly well adapted to long-term single-molecule tracking.

International Nuclear Information System (INIS)

Results of studies dealing with improvement of the currently employed technology of iodine and bromine production by processing iodine- and bromine-containing borehole effluent water were considered. Potentiality of selective oxidation of iodide-ions in the presence of bromide-ions in acidified borehole effluent water with addition of ozone for initiating oxidation of iodide-ions and iron(2) salt to prevent bromine evolution was confirmed experimentally. Conditions were determined that rule out bromine formation in the solution, but simultaneously permit varying the yield of iodine within 70-100%

Energy Technology Data Exchange (ETDEWEB)

Results on the oxidative dehydrogenation of ethane on rare-earth oxide (REO) based catalysts (Na-P-Sm-O, Sm-Sr(Ca)-O, La-Sr-O and Nd-Sr-O) are described. Oxygen adsorption was found to be a key factor which determines the activity of this type of catalysts. Continuous flow experiments in the presence of catalysts which reveal strong oxygen adsorption showed that the reaction mixture is ignited resulting in an enhanced heat generation at the reactor inlet. The heat produced by the oxidative reactions was sufficient under the conditions chosen for the endothermic thermal pyrolysis which takes place preferentially in the gas phase. Ignition of the reaction mixture is an important catalyst function. Contrary to non-catalytic oxidative dehydrogenation, reaction temperatures above 700 C could be achieved without significant external heat input. Ethylene yields of up to 34-45% (S=66-73%) ...

Science.gov (United States)

Eight years ago, corrosion and tube denting seriously threatened the reliability and design life of steam generators, especially for closed loop arrangements in pressurized water reactors (PWRs). Concentrated research by the Steam Generator Owners Group (SGOG) diagnosed the causes and produced effective solutions, notably guidelines for water chemistry control in the secondary loop. The guidelines recommend specific levels of water impurities and remedial actions to prevent cooling-water leaks in the condenser, prevent air leaks, limit corrosion product buildup, and remove some impurities while neutralizing others. Continued research in SGOB-II is investigating intergranular corrosion and stress corrosion cracking. 3 figures.

Science.gov (United States)

In this paper, a novel type of a corona discharge plasma reactor was designed, which consists of needle-plate-combined electrodes, in which a series of needle electrodes are placed in a glass container filled with flue gas, and a plate electrode is immersed in the water. Based on this model, the removal of NO and SO2 was tested experimentally. In addition, the effect of streamer polarity on the reduction of SO2 and NO was investigated in detail. The experimental results show that the corona wind formed between the high-voltage needle electrode and the water by corona discharge enhances the cleaning efficiency of the flue gas because of the presence of water, and the cleaning efficiency will increase with the increase of applied dc voltage within a definite range. The removal efficiency of SO2 up to 98%, and about 85% of NOx removal under suitable conditions is obtained in our experiments.

International Nuclear Information System (INIS)

... 978-5-94883-072-8 121 p. SPECIFIC NUCLEAR REACTORS AND

Energy Technology Data Exchange (ETDEWEB)

As evidence of its effectiveness rapidly accumulates, the Lomi process has most recently been used to decontaminate the recirculation loops and the reactor water clean-up unit of a BWR at Monticello in the United States. An average decontamination factor of 23 was achieved in the recirculation loops.

International Nuclear Information System (INIS)

The 105-KE and 105-KW Fuel Storage Basins were constructed more than 35 years ago as repositories for irradiated fuel from the K East and K West Reactors. Currently, the basins contain irradiated fuel from the N Reactor. To continue to use the basins as desired, seismic adequacy in accordance with current US Department of Energy facility requirements must be demonstrated. The 105-KE and 105-KW Basins are reinforced concrete, belowground reservoirs with a 16-ft water depth. The entire water retention boundary, which currently includes a portion of the adjacent reactor buildings, must be qualified for the Hanford Site design basis earthquake. The reactor building interface joints are sealed against leakage with rubber water stops. Demonstration of the seismic adequacy of these interface joints was initially identified as a key issue in the ...

Science.gov (United States)

Liquid Phase Catalytic Exchange (LPCE)- Cryogenic Distillation(CD) process was studied which could be available for an optimal tritium removal process of pressurized heavy water reactor system at Wolsung nuclear power plant in the near future. Based upon ...

Science.gov (United States)

The Wolsung-type nuclear fuel localization project carried out since 1981 finally reached to a full-fledged phase in 1987. We successfully produced and timely delivered a yearly demand of nuclear fuel for Wolsung unit 1. In this report we studied and summ...

Energy Technology Data Exchange (ETDEWEB)

The paper discusses two petrochemical selective oxidation reactions namely the practised formation of styrene (STY) and the desired oxidative functionalisation of propane. The present knowledge about the mode of operation of oxide catalysts is critically considered. The dehydrogenation of ethylbenzene (EB) should be described by an oxidehydration with water acting as oxidant. The potential role of the coke formed during catalytic reaction as co-catalyst will be discussed. Selective oxidation is connected with the participation of lattice oxygen mechanism which transforms unselective gas phase oxygen into selective oxygen. The atomistic description of this process is still quite unclear as well as the electron structural properties of the activated oxygen atom. The Role of solid state acidity as compared to the role of lattice oxygen is much less well ...

International Nuclear Information System (INIS)

A review of the performance of steam generator tubes in 116 water-cooled nuclear power reactors showed that tubes were plugged at 54 (46 percent) of the reactors. The number of tubes removed from service decreased from 4 692 (0.30 percent) in 1981 to 3 222 (0.20 percent) in 1982. The leading causes of tube failures were stress corrosion cracking from the primary side, stress corrosion cracking (or intergranular attack) from the secondary side and pitting corrosion. The lowest incidence of corrosion-induced defects from the secondary side occurred in reactors that have used only volatile treatment, with or without condensate demineralization.

International Nuclear Information System (INIS)

Existing applications of Alloy 800 are summarized, with particular reference to its use in various types of reactor. The need for a co-ordinated research and development programme is stressed, and the variables to be explored are outlined. The papers relating to the problem of corrosion and cracking in water and steam are considered. the strength and ductility of Alloy 800 is considered. Finally, sections of the summary deal with the use of Alloy 800 for (a) sodium cooled fast reactor boiler tubes; (b) the high temperature gas cooled reactor; and (c) PWR steam generator tubes. (U.K.).

International Nuclear Information System (INIS)

The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment ...

International Nuclear Information System (INIS)

Problem areas in BWRs, PWRs and PHWRs, from the viewpoint of chemistry, and the problem of fission product release in nuclear reactors are discussed. These problem areas are : fuel performance, off-normal water chemistry due to condenser leaks, the transport and deposition of the activated corrosion and fission products, denting in steam generators (in the case of PWRs), ingress of air in the cover gas helium and consequent radiolysis of D_2O in the moderator circuit (in the case of PHWRs). (M.G.B.).

International Nuclear Information System (INIS)

On the 3. and 4. November 1982 the sixth conference of the Corporation for Reactor Safety (GRS) was held in Cologne's Guerzenich. The theme of this year's meeting was the 'Status of Risk Investigations at Nuclear Power Plants'. A principal topic was a report on findings made by the GRS during the 'Risk Oriented Analysis SNR-300'. The second topic comprised the newest developments within Phase B of the Risk Study of Water Pressure Reactors, the discussion of the dose/effect relationship and considerations on threshold risk values. (orig.).

Energy Technology Data Exchange (ETDEWEB)

To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the Canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. Bubbles containing reaction products enhance the rate of transfer of ...

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An experimental and modelling study was performed for a reverse flow catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter had a segmented ceramic monolith honeycomb substrate and a catalytic washcoat containing a predominantly palladium catalyst. A one-dimensional single channel model was used to simulate the operation of the converter. The kinetics of the CO and methane oxidation followed first-order behaviour. The activation energy for the oxidation of methane showed a change with temperature, dropping from a value of 129 to 35 kJ/mol at a temperature of 874 K. The reverse flow converter was able to achieve high reactor temperature under conditions of low inlet gas temperature, provided that the initial reactor temperature was sufficiently high. (author)

Energy Technology Data Exchange (ETDEWEB)

This specification establishes requirements for design, testing, and quality assurance for electric heaters that will be used to maintain primary Sodium temperature in the Fast Test Facility (FFTF) reactor vessel. The Test Specification (WHC-SD-FF-SDS-003) has been revised to Rev. 1. This change modifies the fabrication of approximately 25 feet of the subject heater using ceramic insulators over the heater lead wire rather than compressed magnesium oxide. Also, 304 or 316 stainless steel can be used for the heater sheath. This change should simplify fabrication and improve the heater operational reliability.

Energy Technology Data Exchange (ETDEWEB)

The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet ...

Energy Technology Data Exchange (ETDEWEB)

CeO{sub 2}-TiO{sub 2} catalysts are prepared by coprecipitation method, and the activity and stability in the catalytic wet air oxidation (CWAO) of phenol are investigated in a batch reactor and packed-bed reactor. CeO{sub 2}-TiO{sub 2} mixed oxides show the higher activity than pure CeO{sub 2} and TiO{sub 2}, and CeO{sub 2}-TiO{sub 2} 1/1 catalyst displays the highest activity in the CWAO of phenol. In a batch reactor, COD and TOC removals are about 100% and 77% after 120 min in the CWAO of phenol over CeO{sub 2}-TiO{sub 2} 1/1 catalyst at reaction temperature of 150 {sup o}C, the total pressure of 3 MPa, phenol concentration of 1000 mg/L, and catalyst dosage of 4 g/L. In a packed-bed reactor using CeO{sub 2}-TiO{sub 2} 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 {sup o}C, the air total pressure of ...

Energy Technology Data Exchange (ETDEWEB)

Chlorination of water can lead to the formation of chloropicrin. The numerous potential precursors (of various reactivities) observed during this study, confirm this hypothesis. Combination of ozonation and chlorination can also lead to the formation of this compound, dangerous to health; however, the conditions of the formation and particularly the impact of a nitration reaction in the gas phase are still not clearly defined.

Energy Technology Data Exchange (ETDEWEB)

Numerous studies have investigated degradation of individual endocrine disrupting compounds (EDCs) in lab or natural waters. However, natural variations in water matrices and mixtures of EDCs in the environment may confound analysis of the treatment efficiency. Because chemical based analytical methods cannot represent the combined or synergistic activities between water quality parameters and/or the EDC mixtures at environmentally relevant concentrations ({mu}g L{sup -1}-ng L{sup -1}), bioanalytical assessments of residual estrogenic activity in treated water were used to evaluate the performance of the UV based advanced oxidation process for estrogenic contaminants in water. Four EDCs including estradiol (E{sub 2}), ethinyl estradiol (EE{sub 2}), bisphenol-A (BPA) and nonylphenol (NP) were spiked individually or as a mixture at {mu}g L{sup -1}-ng L{sup -1} in ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility has been in operation for approximately five years, including about one thousand days of full power operation of the Fast Test Reactor. During that time the collective dose equivalents received by operating personnel have been about two orders of magnitude lower than those typically received at commercial light water reactors. No major contamination problems have been encountered in operating and maintaining the plant, and release of radioactive gas to the environment has been minimal and well below acceptable limits. All shields have performed satisfactorily. Experience to date indicates an apparent radiological superiority of liquid metal reactor systems over current light water plants.

Energy Technology Data Exchange (ETDEWEB)

At present, two types of reactors, Pressurized Light Water Reactor(PLWR) and Pressurized Heavy Water Reactor(PHWR), are operating and under construction in Korea. They are much different in design concepts and inherent features from each other so that the calculation methods for Exclusion Area Boundary(EAB) are also different from each other. Thus, the domestic calculation methodology has been applied to PHWR, Wolsung 2, 3 and 4. In this report, the regulatory requirements and methodologies for EAB of Canadian methodology for EAB has been also investigated. It has been examined that the Canadian methodology which has been applied to the calculation of EAB of Wolsung 2, 3 and 4 can be said to be conservative enough compared to physical phenomena. 4 tabs., 3 figs., 22 refs. (Author).

Energy Technology Data Exchange (ETDEWEB)

The oxidation of carbon black, CB, in presence of CeO{sub 2} is investigated to gain a better understanding of the effect of the contact between the two solids during this reaction. Different CB/CeO{sub 2} mixtures are tested in a fixed bed reactor. The experimental data are used to propose a model for CB oxidation in presence of CeO{sub 2}. It accounts for the size distribution of CeO{sub 2} particles, the contact area between CB and CeO{sub 2}, the mass of CB in the sample and the initial ratio CB/CeO{sub 2}. Corresponding kinetic parameters are determined. 35 refs., 10 figs., 3 tabs.

International Nuclear Information System (INIS)

Research highlights: ? We model power oscillations in boiling water reactors using a lumped parameter model. ? The nature and amplitudes of oscillations is obtained using a nonlinear analysis. ? The method of multiple scales has been used for the analytical treatment. ? Fuel temperature coefficient of reactivity determines the nature of oscillations. ? The presented systematic method of analysis useful for reduced order reactor models. - Abstract: In this paper, we perform a parametric study of the nonlinear dynamics of a reduced order model for boiling water reactors (BWR) near the Hopf bifurcation point using the method of multiple scales (MMS). Analysis has been performed for general values of the parameters, but the results are demonstrated for parameter values of the model corresponding to the advanced heavy water reactor (AHWR). The ...

Energy Technology Data Exchange (ETDEWEB)

This standard addresses the design bases for light water reactor, nuclear power plant structures and components essential for the protection of public health and safety from the potential adverse effects of pipe whip, jet impingement, pressurization of compartments outside containment, environmental conditions and flooding associated with a postulated pipe rupture. The design bases for missile protection and the design bases for containment pressurization are not within this standard.

International Nuclear Information System (INIS)

This paper reports that the excess of U.S. electrical generating capacity which has existed for the past 15 years is coming to an end as we enter the 1990s. Environmental and energy security issues associated with fossil fuels are kindling renewed interest in the nuclear option. The importance of these issues are underscored by the National Energy Strategy (NES) which calls for actions which are designed to ensure that the nuclear power option is available to utilities. Utilities, utility associations, and nuclear suppliers, under the leadership of the Nuclear Power Oversight Committee (NPOC), have jointly developed a 14 point strategic plan aimed at establishing a predictable regulatory environment, standardized and pre-licensed Advanced Light Water Reactor (ALWR) nuclear plants, resolving the long-term waste management issue, and other enabling conditions. GE is participating in this national effort and GE's family of advanced nuclear power ...

International Nuclear Information System (INIS)

Microprocessor based ''smart'' pressure, level, and flow transmitters were tested to determine the radiation hardness of this class of electronic instrumentation for use in reactor building applications. Commercial grade Complementary Metal Oxide Semiconductor (CMOS) integrated circuits used in these transmitters were found to fail at total gamma dose levels between 2500 and 10,000 rad. This results in an unacceptably short lifetime in many reactor building radiation environments. Radiation hardened integrated circuits can, in general, provide satisfactory service life for normal reactor operations when not restricted to the extremely low power budget imposed by standard 4--20 mA two-wire instrument loops. The design of these circuits will require attention to vendor radiation hardness specifications, dose rates, process control with respect to radiation hardness factors, and non-volatile programmable ...

International Nuclear Information System (INIS)

In the radiochemical reprocessing of spent fuel from nuclear reactors, a considerable amount of liquid, solid, and gaseous waste is formed; this waste is potentially dangerous to humans and requires the development of special and complex technological techniques for its localization and reliable long-term storage. The most hazardous are liquid wastes of high specific activity - water-tailings solutions obtained in the first cycle of extraction after the removal of uranium and plutonium. These solutions contain more than 99.9% of all the other transuranic elements - isotopes of neptunium, americium, and curium. Where necessary, some fission products and actinides may be removed from wastes of high specific activity for subsequent use. The quantity, composition, and activity of these wastes varies within broad limits, depending on the type and power of the reactor, the initial nuclide composition of the fuel, and its specific ...

Energy Technology Data Exchange (ETDEWEB)

Work at Institutt for energiteknikk (IFE) comprises both nuclear and non-nuclear activities. The main nuclear program is centered on the Halden Reactor Project. In 1958, the first Halden Reactor Project Agreement was signed by organisations representing 12 European countries. During 1994 France became a full member and associate membership was established with Russia. Accordingly, 16 countries were participating in the Project by the end of the year. The objectives have evolved from being simply a demonstration of the operation of a boiling heavy-water reactor to becoming a substantial research and development programme covering the domains of human-machine interaction, fuel behaviour, materials testing, water chemistry, and instrumentation. In 1994, significant progress was achieved in all of the areas addressed by the project, including the re-instrumentation of irradiated fuel ...

International Nuclear Information System (INIS)

Heat transfer tubes of a primary pressurized water cooled (PPWC) in the high temperature engineering test reactor (HTTR) form the reactor pressure boundary of the primary coolant, therefore are important from the viewpoint of safety. To establish inspection techniques for the heat transfer tubes of the PPWC, an automatic inspection system was developed. The system employs a bobbin coil probe, a rotating probe for eddy current testing (ECT) and a rotating probe for ultrasonic testing (UT). Nondestructive test of a half of the heat transfer tubes of the PPWC was carried out by the automatic inspection system during reactor shutdown period of the HTTR (about 55% in the maximum reactor power in this paper). The nondestructive test results showed that the maximum signal-to-noise ratio was 1.8 in ECT. Pattern and phase of Lissajous wave, which were obtained for the heat transfer tube of ...

Energy Technology Data Exchange (ETDEWEB)

The Materials and Components Technology Division (MCT) provides a research and development capability for the design, fabrication, and testing of high-reliability materials, components, and instrumentation. Current divisional programs related to nuclear energy support the development of the Integral Fast Reactor (IFR): life extension and accident analyses for light water reactors (LWRs); fuels development for research and test reactors; fusion reactor first-wall and blanket technology; and safe shipment of hazardous materials. MCT Conservation and Renewables programs include major efforts in high-temperature superconductivity, tribology, nondestructive evaluation (NDE), and thermal sciences. Fossil Energy Programs in MCT include materials development, NDE technology, and Instrumentation design. The division also has a complementary instrumentation effort in support of Arms Control ...

International Nuclear Information System (INIS)

By its very nature redox potential measurement is suitable for determining the concentration ratio of a stable redox pair through its interaction with a chemically inert electrode surface but not the absolute concentration of a material. The measured redox potentials agree only rarely with those which are easily calculable theoretically. No individual defined stable redox pair is available in power station water. It is therefore not simply possible to measure definable mixed potentials more precisely. For these reasons redox potential measurement in the power station, as also with other types of water, can no longer be regarded as an indicator, by which it can be established whether oxidizing or reducing materials predominate in the water. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Banana (Musa acuminata Colla AAA) peel extracts obtained in this work had a high capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2prime-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS+) free radicals, and they were also good lipid peroxidation inhibitors. Acetone:water extracts were considerably more effective (compared with methanol, ethanol, acetone, water, methanol:water or ethanol:water) at inhibiting the peroxidation of lipids in the b-carotene/linoleic acid system or scavenging free radicals. However, aqueous extracts had a high capacity to protect lipids from oxidation in the thiobarbituric acid reactive substances (TBARS) test, as well as in the b-carotene bleaching assay. In addition, acetone:water most efficiently extracted all extractable components (54+-...

British Library Electronic Table of Contents (United Kingdom)

Spherical nano-sized YSZ (yttria stabilized ZrO2) powders were successfully synthesized via a reverse microemulsion system. The water droplets in the microemulsion system of yclohexane/water/span85/Triton X-100/hexyl alcohol can act as the nano-reactors which solubilize zirconium oxychloride and ammonia water separately. The minute original reactors are favor to the formation of nano-sized spherical YSZ powders and the dispersibility of the powders can be controlled effectually by adjusting the weight ratio of the LiNO3 molten salt to the precursor. The phase transformation from cubic to monoclinic starts at and 500??C and finally monoclinic and cubic phase with increased crytallinity coexist at 800??C. The effect of LiNO3 molten salt in the formation of YSZ powders was also discussed.

International Nuclear Information System (INIS)

Purpose: To provide a feedwater control device capable of minimizing the adverse response of steam drum level at low power. Consitution: In order to perform feedwater control at low power by the substantial control of three factors, that is, main steam flow rate, feedwater flow rate and steam drum level, the main steam flow rate is determined from the reactor output and feedwater rate is determined from the changes in the feedwater temperature due to the mixing of waters in the reactor clean up system and feedwater. If a difference is resulted between these flow rates, a starting feedwater regulator is controlled instantly to eliminate the difference. The water level in the steam drum is used for amending the difference from the final set value of the drum water level, by which the adverse response of the steam drum level can be minimized. (Seki, T.).

Energy Technology Data Exchange (ETDEWEB)

The potential for detoxification and deodorization of sulfide-laden water (sour water) by microbial treatment was evaluated at a petroleum production site under field conditions. A sulfide-tolerant strain of the chemautotroph and facultative anaerobe, Thiobacillus denitrificans, was introduced into an oil-skimming pit of the Amoco Production Company LACT 10 Unit of the Salt Creek Field, Wyoming. Field-produced water enters this pit from the oil/water separation treatment train at an average flowrate of 5,000 bbl/D (795 m{sup 3}/D) with a potential maximum of 98,000 bbl/D (15,580 m{sup 3}/D). Water conditions at the pit inlet are 4,800 mg/l TDS, 100 mg/l sulfide, pH 7.8, and 107{degrees}F. To this water an aqueous solution of ammonium nitrate and diphosphorous pentoxide was added to provide required nutrients for the bacteria. The first 20% of the pit was aerated ...

International Nuclear Information System (INIS)

This paper presents a brief overview of refuse derived fuel (RDF) processing systems, and the different types of RDF. The quality of RDF, combustion of RDF in fluidized beds, and moving grate reactors, operating conditions, emissions (sulphur dioxide, nitrogen oxides, carbon monoxide and hydrogen chloride) and thermal efficiency are discussed. (UK).

International Nuclear Information System (INIS)

Results of calculational investigations into circulation of water and steam-and-water mixture in the PGV-1000 steam generator heat exchanger bundle used at NPPs with the WWER-1000 reactors, are considered. Model of water circulation in horizontal steam generator with submerged heating surface under conditions of steam generation irregularity along the heat transfer tubes is made. On the basis of the obtained data the assumption is made about water essential overflows from the hot collector zone into the cold one. Overflow rate over the upper line of the heat transfer tubes may constitute 0.7 m/s. The conclusion is made about the necessity to set up the vertical barrier which divides hot and cold sections of heat transfer tubes and helps to avoid water transverse overflows.

Energy Technology Data Exchange (ETDEWEB)

The current work continues a project completed in 1999 by ReMaxCo Technologies in which a novel, microwave based, VLS Silicon Carbide Fibrils concept was verified. This project continues the process development of a pilot scale commercial reactor. Success will lead to sufficient quantities of fibrils to expand work by ORNL and others on heat exchanger tube development. A semicontinuous, microwave heated, vacuum reactor was designed, fabricated and tested in these experiments. Cylindrical aluminum oxide reaction boats are coated, on the inner surface, with a catalyst and placed into the reactor under a light vacuum. A series of reaction boats are then moved, one at a time, through the reactor. Each boat is first preheated with resistance heaters to 850 C to 900 C. Each reaction boat is then moved, in turn, to the microwave heated section. The catalyst is heated to the required ...

International Nuclear Information System (INIS)

Tarapur Atomic Power Station Unit-3 and 4 (TAPS -3 and 4) are the 540 MWe reactors. Unit-4 attained first criticality on 06th March 2005 and operated for about 230 effective full power days (EFPD). Unit-3 attained first criticality on 21st May 2006 and operated for about 20 EFPD. With the reactor operation radiation field increases on the Primary Heat Transport system equipments, Moderator system equipments and auxiliary system equipments due to deposition of fission products and activation products in different reactor systems. These dose rates significantly contributes to the external exposure and stations collective dose during reactor operation, refueling operation and maintenance activities. A study was undertaken at TAPS 3 and 4 to identify the system equipments showing the significant dose rates and identify the radionuclides present in the primary heat transport system, Moderator systems, cover ...

Energy Technology Data Exchange (ETDEWEB)

Total hemispherical emittance was measured for the SP-100 reactor fuel cladding alloy (Nb-l% Zr). Based on a standard test method (ASTM C 835-82), experiments were conducted on a reference sample of oxidized stainless steel and then on a sample of actual cladding. The sample is heated in a vacuum by passing DC current through it until reaching equilibrium. Measurements are made of the electrical power dissipated in the sample and of the surface temperature. Using the Stefan-Boltzmann Law and some key assumptions concerning conductive and radiative heat transfer, the measured quantities are used to calculate emittance. Calculated values for unoxidized cladding range from 0.159 +/- 5.35% at 913 K to 0.200 +/- 4.51% at 1091 K. Highest value measured after onset of visible oxidation was 0.339 +/- 3.92% at 1269 K.... SP-100, Reactor, Emittance, Niobium, Fuel cladding, Emissivity.

International Nuclear Information System (INIS)

... power reactors pressure tube reactors reactors THERMAL REACTORS.

Science.gov (United States)

The Army Reactor Area (ARA) II was constructed in the late 1950s as a test site for the Stationary Low Power Reactor No. 1 (SL-1). The SL-1 was a prototype power and heat source developed for use at remote military bases using a direct cycle, boiling water, natural circulation reactor designed to operate at a thermal power of 3,000 kW. The ARA II compound encompassed 3 acres and was comprised of (a) the SL-1 Reactor Building, (b) eight support facilities, (c) 50,000-gallon raw water storage tank, (d) electrical substation, (e) aboveground 1,400-gallon heating oil tank, (f) underground 1,000-gallon hazardous waste storage tank, and (g) belowground power, sewer, and water systems. The reactor building was a cylindrical, aboveground facility, 39 ft in diameter and 48 ft high. The lower portion of the building contained the ...

Energy Technology Data Exchange (ETDEWEB)

Accelerated oxidation treatment technology is introduced for use in the treatment of poor quality water by ozone injected from the bottom of a pressurized ozone contact tank. Under study as oxidation accelerating processes using ozone center about an ozone/hydrogen peroxide treatment, ozone/UV treatment, ozone/hydrogen peroxide/UV treatment, etc. As the result of testing, important respects in accelerated oxidation are learned, which are stated below. In the ozone-aided treatment, there are some substances, such as chromatic matters, that can be removed more rapidly when in direct contact with gaseous ozone. In this case, the concentration of remnant ozone poses an important problem. In relation to the amount of injected hydrogen peroxide, what is important is the ozone/hydrogen peroxide injection ratio relative to the substance that is to be removed. In the use of UV rays, since the decomposition rate ...

International Nuclear Information System (INIS)

... brakes lmfbr type reactors breeder reactors epithermal reactors fast reactors

Energy Technology Data Exchange (ETDEWEB)

The Savannah River Swamp is a 3,020 Ha forested wetland on the floodplain of the Savannah River and is located on the Department of Energy`s Savannah River Site (SRS). Major impacts to the swamp hydrology occurred with the completion of the production reactors and one coal-fired powerhouse at the SRS in the early 1950`s. Water was pumped from the Savannah River, through secondary heat exchangers of the reactors, and discharged into three of the tributary streams that flow into the swamp. This continued from 1954 to 1988 at various levels. The sustained increases in water volume resulted in overflow of the original stream banks and the creation of additional floodplains. Accompanying this was considerable erosion of the original stream corridor and deposition of a deep silt layer on the newly formed delta. Heated water was discharged directly into Pen Branch and ...

Energy Technology Data Exchange (ETDEWEB)

The solar central receiver at the Barstow Pilot Plant is a once-through steam boiler consisting of vertical arrays of Alloy 800 tubes. Water/steam leaks associated with tube bends near the receiver outlet were observed after 16 service months. The leaks resulted from through-wall cracks localized in the crown of tube bends operating in the temperature range from 550 to 650/sup 0/C. Initiation occurred on the ID (steam side) of the tube and propagated transgranular through the tube wall. Cracking was axial and circumferential; in general, the circumferential cracks were more severe than the axial cracks. Thick oxide layers showed on the ID of the receiver tubes; a 25-..mu..m thick oxide layer had formed on tubing which operated at 650/sup 0/C. In addition, an enhanced oxidation layer was observed along a narrow band in the crown of the tube. This band was up to five times thicker than the ...

International Nuclear Information System (INIS)

Stable boiloff of core water during a severe LWR accident, that is, boiloff driven only by the decay power generated below the water level, is tractable analytically and is relatively insensitive to axial power distribution. As might be expected, calculated accident event times are sensitive to the fidelity of the decay power model. During later stages of boiloff, heat transfer or transport of energy from above the water level to the residual water can result in an unstable condition during which the boiloff rate increases greatly. The unstable boiloff phenomenon illustrates the highly nonlinear influence of core heat transfer during meltdown and emphasizes the great accuracy requirements which attend the modeling of the accident during periods of enhanced heat transfer when significant zirconium oxidation is possible.

International Nuclear Information System (INIS)

In General Electric's design of the Simplified Boiling Water Reactor (SBWR), The depressurization valves (DPV) are installed in the reactor pressure boundary: four are connected to the reactor vessel by means of nozzles, and two more are located on the main steam pipes (one DPV for each line), which act during particular transients and/or loss of coolant accidents (LOCA), consequently providing the reactor vessel with a safe quick depressurization system. Once the vessel is de pressurised, the passive gravity-driven cooling system (GDCS) starts to operate, permitting the injection of water required for continuous core cooling. DPVs are leak tight, with welded flaps, actuated by a [striker[hammer***] which is activated by an explosive mixture. The dynamic loads that open these valves include, in addition to those produced by steam (typical in any thermodynamic ...

Energy Technology Data Exchange (ETDEWEB)

An assessment of the cooling requirements for fusion reactor components, such as the first wall and limiter/divertor, was carried out using pressurized water as the coolant. In order to establish the coolant operating conditions, a survey of the literature on departure from nucleate boiling, critical heat flux, asymmetrical heating and heat transfer augmentation techniques was carried out. The experimental data and the empirical correlations indicate that thermal protection for the fusion reactor components based on conventional design concepts can be provided with an adequate margin of safety without resorting to either high coolant velocities, excessive coolant pressures, or heat transfer augmentation techniques. If, however, the future designs require unconventional shapes or heat transfer enhancement techniques, experimental verification would be necessary since no data on heat transfer augmentation techniques exist for ...

International Nuclear Information System (INIS)

An assessment of the cooling requirements for fusion reactor components, such as the first wall and limiter/divertor, was carried out using pressurized water as the coolant. In order to establish the coolant operating conditions, a survey of the literature on departure from nucleate boiling, critical heat flux, asymmetrical heating and heat transfer augmentation techniques was carried out. The experimental data and the empirical correlations indicate that thermal protection for the fusion reactor components based on conventional design concepts can be provided with an adequate margin of safety without resorting to either high coolant velocities, excessive coolant pressures, or heat transfer augmentation techniques. If, however, the future designs require unconventional shapes or heat transfer enhancement techniques, experimental verification would be necessary since no data on heat transfer augmentation techniques exist for ...

International Nuclear Information System (INIS)

Purpose: To effectively cool the reactor core in a steam atmosphere by upwardly directing several of spray nozzles attached to a ring header thereby increasing the flying distance of the spray. Constitution: Ring headers in two upper and lower stages are disposed above the outer circumference of a reactor core and each of the ring headers is mounted with spray nozzles. Among the spray nozzles, at least several nozzles mounted to the ring header at the lower stage are directed such that the center axis for each of the nozzle is raised above the horizontal axis and other several nozzles are mounted with the nozzle center axis directed downwardly from the horizontal axis. Accordingly, even if collapsing phenomenon occurs in the jetting stream due to the condensation in the steams that forms the operation atmosphere of the reactor core spray cooling device, a sufficient amount of emergency cooling water can ...

International Nuclear Information System (INIS)

Scenarios are developed for spent fuel that is taken out of the nuclear reactor and stored for 20 years before reprocessing, and three storage techniques which use a water pool, dry cask or vault are compared with respect to their costs. The storage price (storage cost per kilogram of spent fuel), which is employed as the economic index, is calculated on the assumption that all the charge is paid when the spent fuel is brought in the storage facilities. Four scenarios are assumed for spent PWR and BWR fuels to be stored in at-reactor (AT) or away-from-reactor (AFR) facilities. The capital costs cover the buildings of the storage facilities, equipment, decommissioning, casks for transportation and storage (for cask storage) and casks for transportation (for water pool or vault storage). Costs for operation and maintenance of the facilities are also considered in evaluating these ...

Energy Technology Data Exchange (ETDEWEB)

The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design ...

International Nuclear Information System (INIS)

There has been recent interest in the United States concerning the loss of residual heat removal system (RHRS) under reduced coolant inventory conditions for pressurized water reactors. This issue is also of interest in the Federal Republic of Germany and an experiment was performed in the integral PKL-HI experimental facility at Siemens-KWU to supply applicable data. Recently, an NRC-sponsored effort has been undertaken at the Idaho-National Engineering Laboratory to identify and analyze the important thermal-hydraulic phenomena in pressurized water reactors following the long term loss-of-RHRS during reduced inventory operation. The thermal-hydraulic response of a closed reactor coolant system during such a transient is investigated in this report. Some of the specific processes investigated include: reflux condensation in the steam generators, the corresponding pressure increase ...

Science.gov (United States)

Pd-Ag bimetallic catalysts, supported on gamma-Al2O3, have been evaluated as exhaust catalysts for methanol-fueled vehicles. Laboratory studies have shown that a 0.01% Pd-5% Ag catalyst has greater CO and CH3OH oxidation activity than either 0.01% Pd or 5% Ag catalysts alone. Moreover, Pd and Ag interact synergistically in the bimetallic catalyst to produce greater CO and CH3OH oxidation rates and lower yields of methanol partial oxidation products than expected from a mixture of the single-component catalysts. The Pd-Ag synergism results from Pd promoting the rate of O2 adsorption and reaction with CO and CH3OH on Ag. Rate enhancement by the bimetallic catalyst is greatest at short reactor residence times where the oxygen adsorption rate limits the overall reaction rate.

Energy Technology Data Exchange (ETDEWEB)

The presence of iron and manganese in underground water due to rock leaching may cause problems in drinking water. the oxidation of these metals produces precipitates which alter water quality (by making it cloudy and bad testing) and may even block supply pipes. This article presents a way eliminating this problem which was tried out in the conduits of Cantillana, a municipality in the province of Seville, Spain. Cleaning the pipes with a mixture of H{sub 2}O{sub 2} + water changes the characteristics of the deposits from flocculant and absorbent to sandy following which they are washed away by the pressure of the water. Once the pipes have been cleaned, a minimal amount of maintenance will prevent the formation of new deposits. This article thus a relatively simple and economical solution for recovering water quality as an alternative to ...

International Nuclear Information System (INIS)

Formation of oxidizing and reducing radicals was studied by pulse radiolysis of [Fe(CN)_6]"4"- - BrO_3"- - CN"- system in ethylene glycol - water solvent mixture. Oxidizing #centre dot#BrO_2 and BrO radicals formed by electron scavenging with #centre dot#BrO_2"- were identified and their reactions were investigated. The reaction of hydroxyl radicals with ethylene glycol leads to formation of reactive radicals with reducing properties and of compounds which reduce slowly in dark the ferricyanide formed in the reaction of #centre dot#BrO_2 radical with ferrocyanide. (author) 21 refs.; 7 figs.

Energy Technology Data Exchange (ETDEWEB)

In order to realize improve of reliability and economy by duplicate production, rapid supply of repair parts from standardized storage, such were expected as to have continuous order of standardized plant, to ignore site condition, to avoid expansion of regulatory requirement. Standardization program was planned to limitedly promote standardization of safety-related design concept, major specification and basic system composition of reactor and primary systems. The area of standardization had been tried to expand to BOP such as general arrangement and rad-waste system.

International Nuclear Information System (INIS)

This paper presents the objective, scope, and status of the U.S. Department of Energy's Materials and Structures Program to develop a data base on mechanical properties of structural materials for out-of-core structures and components for LMFBRs. Information on the development of a reference data base on materials for the reactor system, reactor enclosure system, primary heat transport system, intermediate heat transport system, and steam generator system is included. In addition, the development of the data and analyses to account for the effects of temperature and stress, as well as water/steam, sodium, and radiation environments, is described. Plans for the development of alternative materials for future out-of-core applications are presented. (author).

Energy Technology Data Exchange (ETDEWEB)

This document presents an assessment of the severe accident phenomena observed from four Full-Length High-Temperature (FLHT) tests that were performed by the Pacific Northwest Laboratory (PNL) in the National Research Universal (NRU) reactor at Chalk River, Ontario, Canada. These tests were conducted for the US Nuclear Regulatory Commission (NRC) as part of the Severe Accident Research Program. The objectives of the test were to simulate conditions and provide information on the behavior of full-length fuel rods during hypothetical, small-break, loss-of-coolant severe accidents, in commercial light water reactors.

Energy Technology Data Exchange (ETDEWEB)

Recently the real-time neutron radiography system of the Kyoto University Reactor (KUR) has been developed and practically applied to penetrating the side plates of the MTR type reactor fuels and investigation of moving objects. In this paper an application of the KUR neutron TV system to neutron computed tomography (NCT) is described. By using the NTV system, projection data can be acquired in a single measurement and simultaneously the projection image can be observed on a CRT monitor. The Fourier-convolution technique is used to produce the reconstructed image and its image has a good enough quality for revealing water in a small hole of 1.5 mm in diameter. (orig.).

International Nuclear Information System (INIS)

Recently the real-time neutron radiography system of the Kyoto University Reactor (KUR) has been developed and practically applied to penetrating the side plates of the MTR type reactor fuels and investigation of moving objects. In this paper an application of the KUR neutron TV system to neutron computed tomography (NCT) is described. By using the NTV system, projection data can be acquired in a single measurement and simultaneously the projection image can be observed on a CRT monitor. The Fourier-convolution technique is used to produce the reconstructed image and its image has a good enough quality for revealing water in a small hole of 1.5 mm in diameter. (orig.).

International Nuclear Information System (INIS)

Fundamental phenomena of condensation heat transfer at a steam-water interface have been studied related to the thermo-hydrodynamics of the emergency core cooling system for light water reactors. In this study temperature fluctuations near the interface and in the liquid phase were measured using fine thermocouples for a saturated steam-subcooled water co-current stratified two-phase flow in a nearly horizontal rectangular channel, and heat transfer coefficients were determined experimentally. The values of the condensation heat transfer coefficients in this experiment are from 6 to 40 kW/m"2K. In the regions of high Reynolds numbers, as the steam Reynolds numbers become larger, the average interfacial heat transfer coefficients tend to increase. The corelations of Nusselt numbers were obtained from the heat transfer data. (author)

Energy Technology Data Exchange (ETDEWEB)

The effect of adding hydrogen to methane as a fuel for spark ignited engines has been extensively investigated. Both the possibility of adding a limited amount of hydrogen as well as equal amounts of hydrogen and carbon dioxide to natural gas has been investigated. A 10 vol% addition of hydrogen to the natural gas caused a reduction in UHC of approximately 40%, and an increase in efficiency of approximately three percentage points at the test engine. It is unknown if the gain is representative for large engines. Similar results for UHC reduction and efficiency were obtained for combined hydrogen and carbon dioxide addition. The carbon dioxide was added by exhaust gas recirculation. However, the price of hydrogen, makes this idea uneconomical even when carbon dioxide is readily available through recirculation of engine exhaust. Adiabatic prereforming may be used to convert natural gas into methane, hydrogen and carbon dioxide in order to generate hydrogen and at the same time increase ...

Energy Technology Data Exchange (ETDEWEB)

The Reduced-Moderation Water Reactor (RMWR) is a next generation water-cooled reactor, based on the experienced light water reactor (LWR) technology, aiming at effective utilization of uranium resources, high burn-up and long operation cycle and plutonium multiple recycling. These characteristics can be achieved by the high conversion ratio from {sup 238}U to {sup 239}Pu resulted from the higher neutron energy spectrum in comparison to conventional LWRs. Considering the extension of LWR utilization, Japan Atomic Energy Research Institute (JAERI) started the research on it in 1997 and then started a collaboration in the conceptual design study with the Japan Atomic Power Company (JAPC) in 1998, under technical cooperation with three Japanese reactor vendors. In the core design study of the RMWR, several basic core designs with the high ...

Energy Technology Data Exchange (ETDEWEB)

The pilot area of the Vyngapour oil field allotted for MIOR tests contains three injection and three producing wells. These wells were treated in summer 1993 and 1994. Before, during, and after MIOR treatments on the pilot area the chemical compounds of injected and formation waters were studied, as well as the amount and species of microorganisms entering the stratum with the injected water and indigenous bacteria presented in bottomhole zones of the wells. The results of monitoring showed that the bottomhole zone of the injection well already had biocenosis of heterotrophic, hydrocarbon-oxidizing, methanogenic, and sulfate-reducing bacteria, which were besides permanently introduced into the reservoir during the usual waterflooding. The nutritious composition activated vital functions of all bacterial species presented in the bottomhole zone of the injection well. The formation waters from producing ...

Energy Technology Data Exchange (ETDEWEB)

The requirements to design nuclear power plants for the effects of an instantaneous double-ended guillotine break (DEGB) of the reactor coolant piping have led to excessive design costs, interference with normal plant operation and maintenance, and unnecessary radiation exposure of plant maintenance personnel. This report describes an aspect of the NRC/Lawrence Livermore National laboratory-sponsored research program aimed at investigating whether the probability of DEGB in Reactor Coolant Loop Piping of nuclear power plants is acceptably small such that the requirements to design for the DEGB effects (e.g., provision of pipe whip restraints) may be removed. This study estimates the probability of indirect DEGB in Reactor Coolant piping as a consequence of seismic-induced structural failures within the containment of the GE supplied boiling water reactor at the Brunswick nuclear ...

International Nuclear Information System (INIS)

The CATHENA (formerly ATHENA) has been used to simulate the thermalhydraulic behaviour of the WOLSUNG-1 CANDU-600 reactor during the D_20 spill incident of 1984 November 25. A 4-inch (nominal) Liquid Relief Valve inadvertently opened in the reactor auxiliary system during normal reactor operation, resulting in a discharge of heavy water from the primary heat transport system. The valve remained open for approximately 29 minutes. CATHENA is an advanced thermalhydraulic computer code for analysis of postulated loss-of-coolant accidents (LOCA) and transient faults in CANDU nuclear reactors. A full two-fluid (six-equation) representation of the two-phase flow is used. Component models are used to represent pumps, valves, critical discharge, etc., which are necessary to describe the behaviour of the CANDU system under upset conditions. Heat transfer between the fluid and piping walls (or ...

Energy Technology Data Exchange (ETDEWEB)

To get a considerable reduction of the radiotoxicity due to americium, a thermal neutron fluence of 2.10{sup 22} cm{sup -2} or a fast neutron fluence of 2.10{sup 24} cm{sup -2} is required. Irradiation in a thermal neutron flux leads to lower masses of {sup 234}U and precursors and of {sup 237}Np and precursors, but to higher curium masses and much higher neutron emission rates than irradiation in a fast neutron flux. Therefore, irradiation in a fast neutron flux has preference when multiple recycling is adopted. When once-through burning is applied, irradiation in a thermal neutron flux can be applied. Then irradiation in a heavy water reactor (HWR) has preference above irradiation in a PWR or in a high temperature gas-cooled reactor (HTGR). (authors) 4 refs.

International Nuclear Information System (INIS)

For shut-down safety of the turbine generator (securing of auxiliary power operation after load shut-down and preventing the reaching of overspeed after load shut-down with disturbed turbine governing system) additional measures compared to those for superheated steam turbines are required for turbine generators in plants with pressurized water reactor (PWR) as well as those with boiling water reactor (BWR) . Equipment is described (e.g. overspeed govern or selecting connection, vacuum breaker, bypass valves, intercepting valves) which, depending on the own conditions of the individual turbine generator (e.g. run-up time, vacuum, enclosed energy), may be applied alone or in jointly. (orig.).

Energy Technology Data Exchange (ETDEWEB)

In nuclear reactor safety research, the question of the possible consequences of delayed core reflood during severe accidents or anticipated transient without scram transients in boiling water reactors (BWRs) has been raised. One can envisage a very low probability accident scenario leading to core uncovery and core heat-up, followed by control blade melting and subsequential delayed reflooding of the core with unborated water before its degradation. Reflooding of the hot core causes significant increases in the peak heating, melting, and hydrogen production rates, thus increasing the probability of core degradation. However, as has been established, debris beds formed from shattered fuel rods and quenched fuel melt will be undermoderated. The reflood process of a voided, intact core was examined using the TRAC/BFI CODE.

International Nuclear Information System (INIS)

Level 1 and 2 probabilistic safety assessments (PSAs) for both internal and external events are being performed to meet one of the conditions for a construction permit for Wolsong units 2, 3, and 4 in Korea. These units are CANDU-6 Pressurized Heavy Water Reactors (PHWRs), and the study is the first comprehensive level 1 and 2 PSAs for CANDU type plants in the world. The detailed PSA includes and extensive fault tree, event tree analysis, human reliability analysis, and common cause failure analysis. Event trees have been developed for 35 internal initiating event groups. The preliminary results show that the total core damage frequency for Wolsong units 2, 3, and 4 each is similar to that for a typical PWR plant. (author).

International Nuclear Information System (INIS)

Object: To suppress a quantity of impurities in a coolant fed into a reactor vessel. Structure: The concentration of oxygen in a coolant flowing from a condensation desalting instrument into a feed and condensation piping is measured by an oxygen-concentration detector to feed its signal to an adjusting instrument. A degree of opening of an oxygen flow control valve to maintain the concentration of oxygen in the cooling water flowing within the pipe in the range from about 10 to about 200 ppb. Also, the concentration of oxygen in the cooling water fed to the desalting instrument is maintained at a level less than 2 ppb. Thereby, the total amount of iron flown into the vessel can be suppressed to a fine amount such as less than about 1 ppb. (Kawakami, Y.).

CERN Document Server

A new methane cold neutron source has been tested at the IBR-2 pulsed reactor at the Frank Laboratory of Neutron Physics. In a paper the results of experiments at neutron diffractometers HRFD and DN-2 which are placed at the IBR-2 from the methane moderator side are given. A comparison with the results obtained with the conventional water comb-like moderator is performed. The perspectives of the cold source for various kinds of neutron diffraction experiments, including atomic and magnetic structural analysis and real time experiments are discussed. It is shown, that for a huge number of the experiments which are performing at both HRFD and DN-2 the methane cold neutron source provides the better conditions than water comb-like moderator.

Energy Technology Data Exchange (ETDEWEB)

AREVA is the world leader in the design and construction of nuclear power plants, the manufacture of heavy components, and the supply of nuclear fuel and nuclear services such as maintenance and inspection. The Equipment Division provides the widest range of nuclear components and equipment, manufactured at its two facilities in Jeumont, northern France, and St. Marcel, in Burgundy. The St. Marcel plant, set on 35 ha (87.5 acres) near Chalon-sur-Saone, was established in 1973 in a region with a long history of specialized metalworking and mechanical activities to meet the demand for non-military nuclear requirements in France. The site offers two advantages: - excellent facilities for loading and transporting heavy components on the Saone river, - it's proximity to other group sites. Since its completion in 1975, the Chalon/St. Marcel facility has manufactured all the heavy components for French pressurized water reactors (PWRs) ...

Energy Technology Data Exchange (ETDEWEB)

A solid electrolytic capacitor having a solid electrolyte comprising manganese dioxide dispersed in an aromatic polyamide capable of further cure to form polyimide linkages, the solid electrolyte being disposed between a first electrode made of valve metal covered by an anodic oxide film and a second electrode opposite the first electrode. The electrolyte autogenously produces water, oxygen, and hydroxyl groups which act as healing substances and is not itself produced pyrolytically. Reduction of the manganese dioxide and the water molecules released by formation of imide linkages result in substantially improved self-healing of anodic dielectric layer defects.

Science.gov (United States)

Experimental tests were performed in a continuous-flow hydrotreating unit at Pittsburgh Energy Technology Center to evaluate the performance of hydrous titanium-oxide supported (HTO) catalysts as hydrotreating catalysts for use in two-stage coal liquiefaction. Catalysts containing either a combination of CO, Ni, and Mo as the active metal components or Pd as the active metal componet were tested with representative hydrotreater feed stocks from the Wilsonville Advanced Coal Liquefaction Research and Development Facility. Catalyst performance evaluation was based on desulfurization and denitrogenation activity, the conversion of cyclohexane-insolbule material, and hydrogenation activity during 100-hour reactor runs. Results indicated that the HTO catalysts were comparable to a commercial Ni/Mo-alumina supported catalyst in the areas evaluated. 11 refs., 1 fig., 6 tabs.

International Nuclear Information System (INIS)

A major new initiative to develop and irradiate a long-life mixed oxide fuel system in the Fast Flux Test Facility (FFTF) has been implemented by the Westinghouse Hanford Company at the Hanford Engineering Development Lab. for the US Dept. of Energy. The purpose of this new fuel system, called the Core Demonstration Experiment (CDE), is to demonstrate the capability of achieving a 3-yr life in a prototypical heterogeneous reactor environment under prototypical power and temperature conditions. Three Core Demonstration Lead Experiments (CDLEs) will establish the performance characteristics of entire fuel assemblies of wire-wrapped, large diameter, advanced oxide fuel pins with HT-9 stainless steel alloy cladding and wire wrap and an HT-9 duct. Their performance characteristics provided the basis for design, fabrication, and irradiation of the CDE.

International Nuclear Information System (INIS)

SiC has been considered as a primary candidate material for a first wall component in future fusion reactor because it has been claimed that SiC has excellent high-temperature properties, good chemical stability and low activation. However, the behavior of tritium on SiC has not been discussed yet. In this study, tritium trapping capacity on the surface of SiC was experimentally obtained at the temperature range of 25-800 deg. C in consideration of tritium trapping to the experimental system. The capacity, which was independent of the water vapor pressure in the gas phase and the temperature, was determined as about 10"6 Bq/cm"2. The isotope exchange reaction rate between tritiated water in a gas phase and hydrogen on the surface was quantified at the temperature of 25, 500 and 700 deg. C in consideration of the behavior of tritium trapping at change of experimental condition by the numerical curve fitting method applying ...

International Nuclear Information System (INIS)

A major initiative to develop and irradiate a long-life, mixed-oxide fuel system in the Fast Flux Test Facility (FFTF) has been implemented by Westinghouse Hanford Company for the US Department of Energy. The FFTF, shown in Figures 1 and 2, is a 400 megawatt thermal, fast liquid metal reactor that tests liquid metal, space and fusion fuels and materials. The new fuel system, called the Core Demonstration Experiment (CDE) demonstrates the capability of achieving a three- to four-year life in a prototypic heterogeneous reactor environment under prototypic power and temperature conditions. This fuel system will greatly increase fuel performance and lifetime from the current standard FFTF driver fuel. New design features, fabrication development, CDE assembly fabrication, and irradiation status have been described.

Energy Technology Data Exchange (ETDEWEB)

During FY1997, the JMTR was operated for 3 complete cycles (120th, 121st and 122nd cycles) and was utilized for the research and development programs on the technology of LWRs and fusion reactor, as well as for fundamental research of fuels and materials, and for radioisotope productions. The improvement of evaluation technique in a local neutron spectrum for irradiation utilization and development of capsule having the vertical migration, the reinstrumentation and loading mechanism have been carried out. Development of a new oxygen potential sensor for oxide fuel pellets has been done as an elemental technology of irradiation for high burn-up fuels. As for post irradiation examination, the techniques for measuring of crack length using an alternating current potential drop method and machining of miniaturized specimen by the remote handling have been developed. A research on the blanket materials and components for thermonuclear fusion ...

International Nuclear Information System (INIS)

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO_2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though ...

Energy Technology Data Exchange (ETDEWEB)

The structural integrity of the Fuel Test Loop(FTL) in a Korean experimental reactor is evaluated when the FTL, submerged in a water environment, is subjected to a postulated pipe rupture. The analyses are performed under static and dynamic conditions, imposing the thrust force history at each postulated pipe rupture section. Through analysis the following results are found: 1) A double ended guillotine can not be expected based on the toughness of the material, 2) the structural integrity of the chimney surrounding the FTL would not impede the structural integrity by the pipe whip. All analyses are performed by finite element methods.

International Nuclear Information System (INIS)

Unit one of Daya Bay, China's first nuclear power plant was officially opened in February 1994. The nuclear island has been built by Framatome and is an improved version of the Gravelines 5 and 6, 900MWe Pressurized Water Reactors. Extra seismic protection has been included because of greater earthquake risk. The heat exchanger capacity has also been increased as the sea cooling water can be at 30"oC. The technical specifications and details of the fuel loading are given. The technical assistance, management and training of Chinese personnel are discussed. Two further units may be built if Daya Bay 1 is successful. (UK).

International Nuclear Information System (INIS)

Optimal neutron energy for boron neutron capture therapy (BNCT) has been studied. Epithermal neutron is superior to thermal neutrons in treating deep-seated tumors. Design of the epithermal neutron column for BNCT has been performed by using a two-dimensional transport calculation code. Aluminum and heavy water are used as moderation materials. A thermal neutron column is also designed using heavy water as thermalization material. The configuration of the facility for treatment and research of BNCT and also for basic radio-biological studies of neutrons has been presented. (author).

Energy Technology Data Exchange (ETDEWEB)

Atmospheric impact of peatlands is a sum of their gas fluxes. In contrast to carbon dioxide, peatlands are net sources for methane (CH{sub 4}). Methane is an end product in the anaerobic decomposition processes and it has greater capacity to absorb infrared radiation than carbon dioxide. Most of the data on the CH{sub 4} release from northern peatlands is from North America. The total amount of methane released from wetlands is calculated to be 110 Tg yr{sup -1} of which 34 percent (38 Tg yr{sup -1}) is estimated to be emitted from the northern peatlands. Peat with high content of nitrogen is a potential source for gaseous nitrogen oxides, i.e. nitrous oxide (N{sub 2}O) and nitric oxide (NO). However, the importance of peatlands in producing these trace gases is poorly known. Nitrous oxide and nitric oxide are important components in the atmospheric chemistry and N{sub 2}O also is ...

International Nuclear Information System (INIS)

Alloy 800 has been used for steam generator (SG) tubing for more than 30 years, primarily in CANDU reactors and in reactors in Germany. The grade of Alloy 800 tubing used for this service has a controlled Ti/C ratio (#>=#12 for CANDU SGs), and this specification is sometimes termed Alloy 800 M or Alloy 800 NG . There have been very few corrosion-related flaws detected in this material in SG service, and, until recently, no incidences of cracking. There has been extensive R and D carried out on Alloy 800 tubing, both in Canada and elsewhere, under a variety of operating conditions, including shutdowns, which show that it has excellent resistance to corrosion-related degradation under specified and appropriate operating conditions. These R and D findings are reflected in the in-service experience. It has been shown from the R and D that Alloy 800 is susceptible to corrosion under acidic conditions, in particular those that can arise as a ...