By Addition Of Material To Coolant Patents (Class 376/306)
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Patent number: 5164152Abstract: A method of reducing flow assisted corrosion of a carbon steel component exposed to flowing low-oxygen water is disclosed. The method comprises forming a coating of a platinum group metal on the carbon steel component, and providing a ratio of hydrogen to oxygen of about 1:8 or greater in the water.Type: GrantFiled: August 2, 1991Date of Patent: November 17, 1992Assignee: General Electric CompanyInventors: Young J. Kim, Leonard W. Niedrach
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Patent number: 5135709Abstract: A method for lowering the corrosion potential on components formed from carbon steel, alloy steel, stainless steel, nickel based alloys, or cobalt based alloys, and exposed to high-temperature water comprised of oxidizing species, comprising: providing a reducing species in the high temperature water that can combine with the oxidizing species, and forming the component to have a catalytic layer of a platinum group metal.Type: GrantFiled: May 13, 1991Date of Patent: August 4, 1992Assignee: General Electric CompanyInventors: Peter L. Andresen, Leonard W. Niedrach
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Patent number: 5132076Abstract: A nuclear reactor having a chemical decontamination system is provided in which every piece of decontamination equipment which processes radioactive materials is located within the containment chamber of the nuclear reactor. This decontamination system therefore presents advantageous safety benefits over an outside of containment system in the unlikely event of a leak of radioactive materials from the decontamination system.Type: GrantFiled: December 18, 1990Date of Patent: July 21, 1992Assignee: Westinghouse Electric Corp.Inventors: Gary J. Corpora, Frank I. Bauer, Gordon A. Israelson, Donald E. Skoczylas
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Patent number: 5130080Abstract: A method of extending the life of components of newly constructed nuclear reactors or newly replaced components of existing reactors is taught. The method involves forming a deposit on the surfaces of metallic elements of the nuclear containment, as well as on the surfaces of internal components which are exposed to high-temperature, high-pressure water and steam. The deposit formed is a deposit of at least one member of the platinum group of metals. The deposit is formed by any of a number of conventional methods such as electroless deposition, electrochemical deposition, chemical vapor deposition, sputtering or other conventional method. In operation, this deposit facilitates the combination of hydrogen and oxygen to form water and thereby aids in reducing the electrochemical corrosion potential of the system to values below a critical potential range that prevents stress corrosion cracking.Type: GrantFiled: April 2, 1990Date of Patent: July 14, 1992Assignee: General Electric CompanyInventor: Leonard W. Niedrach
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Patent number: 5130081Abstract: A method of extending the life of components of in service nuclear reactors or components of existing reactors is taught. The method involves forming a deposit on the surface coatings of metallic elements of the nuclear containment, as well as on the surfaces of encrusted internal components which are exposed to high-temperature, high-pressure water and steam. The deposit formed is a deposit of at least one member of the platinum group of metals. The deposit is formed by electroless deposition. In operation, this deposit facilitates the combination of hydrogen and oxygen to form water and thereby aids in reducing the electrochemical corrosion potential of the system to values below a critical potential that prevents stress corrosion cracking.Type: GrantFiled: April 2, 1990Date of Patent: July 14, 1992Assignee: General Electric CompanyInventor: Leonard W. Niedrach
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Patent number: 5124114Abstract: In a system for detecting abnormal movement of a part of a gas-cooled nuclear reactor, for example abnormal tilting of a boiler unit caused by failure of a boiler support, a tracer material is released into the gas coolant path in response to the movement. The releasing of the material may be effected by causing a gas canister to be pierced as a result of the movement. The presence of the tracer material in the coolant is detected by the coolant monitoring system.Type: GrantFiled: May 9, 1990Date of Patent: June 23, 1992Assignee: NNC LimitedInventor: Roy Bilsborough
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Patent number: 5110537Abstract: A method and apparatus for inspecting the change in a water quality in terms of the change in a corrosion rate by detecting the capacity change between opposed electrodes due to the corrosion of electrode surfaces. As a result, the water quality can be continuously monitored over a long time while leaving the electrodes in the water to be inspected. Thus, the method and apparatus are suited for controlling the water quality especially in an atomic reactor vessel.Type: GrantFiled: February 26, 1990Date of Patent: May 5, 1992Assignee: Hitachi, Ltd.Inventors: Hideo Miura, Asao Nishimura, Shinji Sakata, Tasuku Shimizu, Shigeo Hattori
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Patent number: 5108697Abstract: A primary coolant circuit for cooling a nuclear reactor has wetted mechanically stressed nickel base alloy components such as Alloy 600 tubes in steam generators having oxidized surfaces comprising 1-10 w/o zinc, which tubes are inhibited against primary water stress corrosion cracking. The crack initiation times may be delayed by a factor of two in pressurized water nuclear reactors.Type: GrantFiled: October 19, 1990Date of Patent: April 28, 1992Assignee: Westinghouse Electric Corp.Inventors: John N. Esposito, Judith B. Esposito, Fredric W. Pement
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Patent number: 5093073Abstract: In this decontamination process, the surfaces contaminated with radioactive substances, in particular on components of cooling circuits in nuclear reactors, are treated in a first treatment step with an aqueous decontamination solution, containing chromic acid and permanganic acid, at a temperature in the range from 270 to 350 K, in particular at usual room temperature. The contaminated surface layers are thus oxidized by means of the permanganic acid, while the effect of the chromic acid is that the modified surface layers do not adhere firmly. In a second treatment step, the surface layers thus modified are removed by a chemical treatment in the same temperature range, as a result of dissolution, or/and removed by mechanical or hydraulic action. Aqueous solutions of organic acids are suitable for the chemical treatment in the second treatment step, it also being advantageously possible to add reducing agents and complexing agents and/or corrosion inhibitors.Type: GrantFiled: July 7, 1989Date of Patent: March 3, 1992Assignees: ABB Reaktor GmbH, Paul Scherrer InstitutInventor: Erhard Schenker
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Patent number: 5084235Abstract: A direct cycle type atomic power plant provided with a means for suppressing transfer of radioactive nitrogen compounds generated by nuclear reaction in the core from the reactor water to steam, where an increase in the dose rate in the main steam system and the turbine system due to carry-over of radioactive nitrogen atom, .sup.16 N, generated in the core can be suppressed, and the radioactivity therein can be reduced.Type: GrantFiled: July 19, 1990Date of Patent: January 28, 1992Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.Inventors: Eishi Ibe, Hidetoshi Karasawa, Maroto Nagase, Masaharu Sakagami, Shunsuke Uchida, Minoru Miki, Yamato Asakura, Motoaki Utamura, Fumio Kawamura, Katsumi Ohsumi, Yoshinori Chiba
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Patent number: 5082618Abstract: The method consists in removing the cooling fluid of the primary circuit, and, as a function of the cooling fluid concentration, in passing either all of the cooling fluid into at least one electrodialysis module, or only a part of the cooling fluid into the electrodialysis modules and the other part towards at least one reverse osmosis apparatus, in adding to the cooling fluid, when it leaves the primary circuit, an additive to promote dissociation of the boric acid, and in then returning the cooling fluid into the primary circuit.Type: GrantFiled: June 13, 1989Date of Patent: January 21, 1992Assignee: FramatomeInventor: Philippe Dagard
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Patent number: 5028384Abstract: A measure providing improved personnel safety in the operation of a steam producing, water cooled, boiling water nuclear fission reactor for generating electrical power is disclosed. The measure comprises utilizing catalytic oxidation to inhibit the escape of certain radioactive material from the reactor and its passage through the steam circuit.Type: GrantFiled: August 9, 1989Date of Patent: July 2, 1991Assignee: General Electric CompanyInventors: John M. Skarpelos, Lin, Chien-Chang
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Patent number: 5024805Abstract: Metal surfaces having an oxide coating containing radioactive substances, such as the primary system of a pressurized water reactor, are decontaminated by passage thereover of a decontamination solution containing a weak chelating agent, such as nitrilotriacetic acid, and a ferrous salt, such as ferrous glutonate. The weak chelating agent is present in an aqueous solution in an amount of 0.1 to 2.0 percent by weight and the ferrous salt in an amount to provide 50 to 500 parts per million iron based on the weight of the solution. The solution, after contact with the metal surfaces is regenerated by an ion exchange resin or, preferably, by electrolysis.Type: GrantFiled: August 9, 1989Date of Patent: June 18, 1991Assignee: Westinghouse Electric Corp.Inventor: Alexander P. Murray
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Patent number: 5015436Abstract: A water-cooled direct cycle nuclear plant including a nuclear reactor, a turbine, a condenser, a purifying means and a feed water heater successively arranged as main constitution, further comprises means for measuring iron concentration in cooling water, and means for injection iron into cooling water for controlling iron amount in cooling water at an optimum level. The iron amount to be injected into cooling water is calculated based on the measured iron concentration so as to make the iron accumulation rate on fuel rod to be not less than 0.5 mg/m.sup.2 /hr.Type: GrantFiled: March 29, 1989Date of Patent: May 14, 1991Assignee: Hitachi, Ltd.Inventors: Makoto Nagase, Yamoto Asakura, Motoaki Utamura, Shunsuke Uchida
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Patent number: 4992232Abstract: In a boiling water reactor nuclear plant, hydrogen is injected into the feed water to neutralize radiolysis which causes stress corrosion in stainless steel components. It has been discovered that by inhibiting volatile ammonia, and other gaseous nitrogen compounds from leaving the liquid phase portions of the plant to the steam phase portions of the plant, radiation is reduced to acceptable levels. Formation of ammonia is inhibited chemically, by altering the reaction paths for volatile nitrogen species with trace additives in the parts per billion range, suitable additives include nitrous oxide, copper, zinc, carbon dioxide, and other components. It has also been found that by manipulating the pH, the formation of the voltage nitrogen compounds, especially ammonia, is decreased. Similarly, by physically altering plant operating conditions to reduce sparging or scrubbing of the gases from areas of high radiation, confinement of the N-16 within the liquid phase of the plant within the reactor vessel occurs.Type: GrantFiled: July 17, 1989Date of Patent: February 12, 1991Assignee: General Electric CompanyInventors: Robert L. Cowan, II, Dragomir Duitna, Robert J. Law, Chien-Chang Lin, Carl P. Ruiz, James L. Simpson
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Patent number: 4981641Abstract: A method of inhibiting or reducing contamination of out-of-core components of the primary coolant circuit of a pressurized water reactor due to absorption by oxide films of such components of cobalt and other radioactive contaminants generated by neutron irradiation of coolant impurities while in the reactor core. The method consisting of intermittently (e.g. at reactor shutdown for maintenance purposes), and/or once-off during commissioning of the reactor, holding the temperature of the circulating coolant within a suitable range below normal operating temperature for an extended period while maintaining its boric acid concentration substantially higher than during normal operation. Inhibition of absorpotion by component oxide films persists long-term and predisposes to preferential and improved removal of contamination by the usual purification equipment which operates continuously during normal operation of the reactor.Type: GrantFiled: December 15, 1988Date of Patent: January 1, 1991Assignee: United Kingdom Atomic Energy AuthorityInventor: Peter Campion
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Patent number: 4968478Abstract: A potassium inhibitive blend and corrosion protection method for closed cooling water systems. The closed cooling system circulates about 35 to 40 gallons of corrosion inhibitor per 10,000 gallons of circulating water. The corrosion inhibitor contains potassium molybdate, potassium nitride, and potassium borate in an aqueous solution so that if leakage of the circulated water occurs, the leaked corrosion inhibitive liquid does not cause dangerous radiation in any amounts dangerous to the environment. The potassium molybdate and potassium nitrate each constitute about 12% of the aqueous solution. Potassium based borate at 2 to 2.5%, ethylene glycol preferably at about 10%, and benzotriazole or tolyltriazole of about 0.4% with up to 1% polymeric scale suppressant are also included in the corrosion inhibitive blend.Type: GrantFiled: February 14, 1990Date of Patent: November 6, 1990Inventor: Paul A. Burda
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Patent number: 4950449Abstract: Deposition of radioactive cobalt on the interior surfaces of a water-cooled nuclear reactor and intergranular stress corrosion cracking are inhibited or substantially prevented by the continuous injection of zinc oxide to the reactor water. The zinc oxide may be prepared in the form of a paste, a slurry, or a preformed aqueous solution.Type: GrantFiled: February 26, 1988Date of Patent: August 21, 1990Assignee: General Electric CompanyInventors: George E. Petersen, Randall N. Robinson, Carl P. Ruiz, William J. Marble, Barry M. Gordon, Gerald M. Gordon
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Patent number: 4940564Abstract: In a boiling water-type, nuclear power plant, deposition of radioactive substances on the surfaces of out-of-core components in the primary cooling water system in the nuclear power plant is suppressed by injecting an alkaline element into reactor water in the presence of more than an amount of the oxygen formed by nuclear fission of the reactor water and dissolved in the reactor water, particularly without hydrogen gas injection, during the nuclear heatup operation period of a boiling water type, nuclear power plant and circulating the injected alkaline element through the primary cooling water system of a nuclear reactor, thereby forming an oxide film on the surfaces of out-of-core components in the primary cooling water system of the nuclear reactor. Exposure of plant personnel to radioactivity can be reduced thereby. The present boiling water-type, nuclear power plant is provided with a means for forming such oxide film.Type: GrantFiled: October 20, 1987Date of Patent: July 10, 1990Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.Inventors: Motohiro Aizawa, Katsumi Ohsumi, Takashi Honda, Hisao Itow
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Patent number: 4941112Abstract: A method and a device are disclosed for measuring the lithium concentration in the primary cooling circuit of a nuclear power station reactor. The lithium concentration Li.sup.+ is determined by linear correlation between the electrical conductivity .lambda. of the cooling water measured by measuring means 1, at a given temperature t measured by measuring means 2. Means 4 to measure the boron concentration B make it possible, by means of the computing means 3 to determine the lithium concentration Li.sup.+ according to the decreasing lithium hydroxide specification. The invention can be applied to the maintaining and regulation of the pH of the cooling water of a nuclear power station reactor at a determined value.Type: GrantFiled: May 31, 1988Date of Patent: July 10, 1990Assignee: Electricite de France (National Service)Inventors: Christian Nepveu de Villemarceau, Jean-Luc Pereira, Jean-Pierre Blin, Anne-Marie Arzel, Didier Livigni
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Patent number: 4927598Abstract: The primary cooling water in a primary cooling water recirculation path of a nuclear power plant is heated and recirculated in the presence of beryllium, and a film of nickel ferrite and/or cobalt ferrite is formed on the surface of pipings and various apparatus and devices connecting with the primary cooling water. The beryllium is injected in the form of beryllium ion into the primary cooling water, or is disposed in the form of beryllium or beryllium-containing alloy in the piping and/or the various apparatus and devices.Type: GrantFiled: September 6, 1988Date of Patent: May 22, 1990Assignee: Hitachi, Ltd.Inventors: Yoshitaka Nishino, Toshio Sawa, Katsumi Ohsumi, Hisao Itow
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Patent number: 4926449Abstract: A potassium inhibitive blend and corrosion protection method for closed cooling water systems. The closed cooling system circulates about 35 to 40 gallons of corrosion inhibitor per 10,000 gallons of circulating water. The corrosion inhibitor contains potassium molybdate, potassium nitrite, and potassium borate in an aqueous solution so that if leakage of the circulated water occurs, the leaked corrosion inhibitive liquid does not cause dangerous radiation in any amounts dangerous to the environment. The potassium molybdate and potassium nitrate each constitute about 12% of the aqueous solution. Potassium based borate at 2 to 2.5%, ethylene glycol preferably at about 10%, and benzotriazole or tolyltriazole of about 0.4% with up to 1% polymeric scale suppressant are also included in the corrosion inhibitive blend.Type: GrantFiled: February 22, 1988Date of Patent: May 15, 1990Inventor: Paul A. Burda
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Patent number: 4913849Abstract: A process for pretreatment of chromium-rich oxide surfaces of nuclear reactor cooling system components involves application of a dilute acidic reagent comprising potassium permanganate and chromic acid, at elevated temperatures.Type: GrantFiled: July 7, 1988Date of Patent: April 3, 1990Inventor: Aamir Husain
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Patent number: 4894202Abstract: Disclosed is a method and apparatus for inhibiting radioactive substances eluting into cooling water of a nuclear plant. The method uses an index consisting of an amount of iron adhered onto the fuel cladding surface, that is calculated from the iron concentration of the cooling water and the operation time. A formation of a layer of the iron oxide on the fuel cladding surface is confirmed based upon the covering ratio of 100%. When the covering ratio is smaller than 100%, the iron concentration in the cooling water is controlled to remain constant at a maximum concentration. The Fe/Ni molar concentration ratio in the cooling water is adjusted to be set from about 2 to 10 after the layer of iron oxide reaches a covering ratio of 100%. .sup.58 Co ion and .sup.60 Co ion concentrations in the cooling water can be decreased without greatly increasing the concentration of precipitating radioactive crud, and the surface dosage in the primary system can be decreased at the time of regular checking.Type: GrantFiled: October 2, 1987Date of Patent: January 16, 1990Assignee: Hitachi, Ltd.Inventors: Makoto Nagase, Yamato Asakura, Hidetoshi Karasawa, Masaharu Sakagami, Shunsuke Uchida, Toshio Sawa, Katsumi Ohsumi
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Patent number: 4842811Abstract: An improved boiling water nuclear reactor and method for preventing intergranular stress crack corrosion in the recirculation line of the reactor system where recirculation line coolant water containing dissolved oxygen is diverted from the recirculation loop, hydrogen gas is introduced into the recirculation loop coolant water and the hydrogen-containing recirculation loop coolant water is contacted with a catalyst to enhance reaction of the hydrogen gas with the dissolved oxygen. The deoxygenated recirculation loop coolant water is then returned to the reactor vessel for passage through the core thereof. The hydrogen gas may be added in a stoichiometric amount to remove the dissolved oxygen or in a slight excess so as to suppress radiolysis in the reactor core.Type: GrantFiled: February 5, 1985Date of Patent: June 27, 1989Assignee: Westinghouse Electric Corp.Inventor: Sunil G. Desilva
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Patent number: 4842812Abstract: Colloidal corrosion products which are referred to as crud are removed from nuclear reactor coolant streams by suspending zirconium oxide particles in the coolant stream. The crud will be attracted to the surfaces of the zirconia particles and caused to agglomerate thereon. Such zirconia/crud agglomerates may be readily filtered from the coolant. By providing scavenger particles which comprise active areas of zirconia on basically magnetite particles, after the crud is agglomerated to the active zirconia surfaces, the agglomerates may be removed from the coolant utilizing magnetic separation principles.Type: GrantFiled: September 11, 1987Date of Patent: June 27, 1989Assignee: Westinghouse Electric Corp.Inventors: Armand J. Panson, Michael Troy
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Patent number: 4828790Abstract: A nuclear power plant wherein surfaces of components contacting with nuclear reactor cooling water containing radioactive substances are coated with an oxide film, preferably being charged positively and/or containing chromium in an amount of 12% by weight or more, is prevented effectively from the deposition of radioactive substances thereon.Type: GrantFiled: November 6, 1987Date of Patent: May 9, 1989Assignee: Hitachi, Ltd.Inventors: Takashi Honda, Yasumasa Furutani, Kenya Ohashi, Eiji Kashimura, Akira Minato, Katsumi Ohsumi, Hisao Itou
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Patent number: 4775005Abstract: A method for the corrosion protection of steam generators having a housing containing feed water and enclosing a tube bundle with tubes conducting a heat carrier includes continuously determining the redox potential of the feed water during operation of the steam generator, continuously determining the corrosion potential of at least one tube of the tube bundle during operation of the steam generator, and negatively shifting the redox and corrosion potentials by changing the chemical conditioning of the feed water if the potentials indicate the danger of corrosion, and a device for carrying out the method.Type: GrantFiled: February 11, 1986Date of Patent: October 4, 1988Assignee: Kraftwerk Union AktiengesellschaftInventors: Werner Beyer, Norbert Wieling, Bernhard Stellwag
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Patent number: 4764337Abstract: A corrosion inhibiting aqueous steam generation medium for use in the secondary system of a nuclear steam generator comprises from about 5 to 10 ppm boric acid and an equimolar amount of a polyhydric compound, such as a lower alkyl glycol or glycerol, capable of reacting with the boric acid to increase its acid strength and therefore its corrosion inhibiting properties and produce therewith, a volatile diol boric acid complex.Type: GrantFiled: September 12, 1986Date of Patent: August 16, 1988Assignee: Westinghouse Electric Corp.Inventor: Armand J. Panson
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Patent number: 4759902Abstract: This invention relates to a method of predicting the long-term dose rates from radioactive material on the interior, wetted surfaces of the primary coolant piping of nuclear power reactors. The electrochemical potential of the cooling water of a nuclear power plant is measured over a short-term period with an electrochemical potential measuring device that has an unprefilmed measuring electrode. The results of these electrochemical potential measurements are divided by the result at a prescribed short period of exposure, and these normalized electrochemical potential fractions are plotted versus the logarithm of time. The negative of the slope of the straight line through the plotted data is divided into the measured average Co-60 concentration in the cooling water, and a standard curve of long-term dose rate versus this parameter is used to predict the eventual long-term radiation build-up performance of the nuclear power plant in which the electrochemical potential measurements are made.Type: GrantFiled: October 7, 1986Date of Patent: July 26, 1988Assignee: Advanced Process TechnologyInventor: Larry D. Anstine
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Patent number: 4759900Abstract: Deposition of radioactive cobalt on the interior surfaces of a water-cooled nuclear reactor is inhibited or substantially prevented by the continuous injection of zinc oxide to the reactor water. The zinc oxide may be prepared in the form of a paste, a slurry, or a preformed aqueous solution.Type: GrantFiled: August 27, 1986Date of Patent: July 26, 1988Assignee: General Electric CompanyInventors: George E. Peterson, Randall N. Robinson, Carl P. Ruiz
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Patent number: 4756874Abstract: In water-cooled nuclear reactors where zinc is added to the water to remove or lessen the accumulation of radioactive cobalt, radioactivity arising from the zinc itself as a result of neutron capture is lessened or eliminated entirely by modifying the isotopic composition of the zinc prior to its injection into the system. The modification of the isotopic composition consists of lowering the proportion of .sup.64 Zn or removing this isotope entirely.Type: GrantFiled: December 22, 1986Date of Patent: July 12, 1988Assignee: General Electric CompanyInventors: Carl P. Ruiz, David M. Blaies
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Patent number: 4731124Abstract: A method of applying a descaling reagent comprising a one-electron reducing agent which is a low oxidation state transition metal ion in combination with a complexing agent to a surface to be treated to descale the surface which method comprises:(i) maintaining a low oxidation state transition metal ion either in solution under an inert atmosphere in a container made of or lined with an inert material or as a solid salt under an inert atmosphere;(ii) preparing a solution of the complexing agent and removing oxygen therefrom; and(iii) mixing the ingredients from steps (i) and (ii) either in situ in contact with the surface to be treated, or mixing the ingredients from steps (i) and (ii) prior to application to the surface to be treated under conditions whereby no substantial decomposition of the so-formed reagent occurs.Type: GrantFiled: August 31, 1984Date of Patent: March 15, 1988Assignee: Central Electricity Generating BoardInventors: David Bradbury, Timothy Swan, Michael G. Segal
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Patent number: 4727826Abstract: A model steam generator including an improved feedwater system for monitoring the conditions of the heat exchange tubes within a nuclear steam generator is disclosed herein. The feedwater system generally comprises a first conduit fluidly connected between the boiler vessel of the model steam generator and the feedwater of the nuclear steam generator via a first valve, and a second conduit which is fluidly connected between this boiler vessel and a feedwater reservoir by way of a second valve. The feedwater reservoir is in turn connected to a source of demineralized, deaerated water by means of a third conduit having a third valve. This reservoir is further fluidly connected to the feedwater of the nuclear steam generator by means of a fourth conduit having a fourth valve. The improved feedwater system of the invention gives the operator three running options. First, he may run the model steam generator directly off the feedwater used in the nuclear steam generator.Type: GrantFiled: June 19, 1986Date of Patent: March 1, 1988Assignee: Westinghouse Electric Corp.Inventors: Robert Draper, Donald G. Lorentz
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Patent number: 4722823Abstract: A nuclear power plant using a structural material consisting of metal which comes into contact with a liquid in which radioactive substances are dissolved has a function to suppress the deposition of the radioactive substances. In this function, metal elements constituting the surface layer of the structural material which comes into contact with the liquid are oxidized by injecting oxidizing agents from outside, thereby preliminarily producing an oxide film. The oxidizing agents comprise at least one kind selected from the group consisting of oxygen, hydrogen peroxide, chromate, nitrite, molybdate, tungstate and ferrate. Particularly, by suppressing the deposition of radioactive substances on a stainless steel, the dose rate of exposure of workers is effectively reduced.Type: GrantFiled: August 24, 1983Date of Patent: February 2, 1988Assignee: Hitachi, Ltd.Inventors: Takashi Honda, Toshio Kawakami, Masakiyo Izumiya, Akira Minato, Katsumi Ohsumi
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Patent number: 4704235Abstract: A method of decontaminating radionuclide-contaminated acid insoluble corrosion products from primary system surfaces in pressurized water reactors by oxidation and concurrent dissolution in an acidic decontamination solution of the corrosion products which have been made acid-soluble by the oxidation. The characterizing feature of the method is that the oxidation is carried out at relatively low temperatures with a water-based oxidation agent having a pH below 7 and containing cerium nitrate, chromic acid and ozone.Type: GrantFiled: October 4, 1985Date of Patent: November 3, 1987Assignee: Studsvik Energiteknik ABInventor: Jan Arvesen
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Patent number: 4698198Abstract: A plasma device for use in controlling nuclear reactions within the plasma including a first wall and blanket formed in a one-piece structure composed of a solid solution containing copper and lithium and melting above about 500.degree. C.Type: GrantFiled: February 4, 1986Date of Patent: October 6, 1987Assignee: The United States of America as represented by the United States Department of EnergyInventor: Dieter M. Gruen
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Patent number: 4609523Abstract: A passive method of adjusting the pH of the liquid used to flood the containment structure of a nuclear reactor following an accident such as loss of primary or secondary coolant. Perforated containers or baskets, which contain a pH adjusting chemical which is soluble in the flooding liquid (usually a slightly acidic solution of borated water) and which are covered or encapsulated with a plastic protective material, which is like soluble in the flooding liquid, are located in the emergency containment sumps.Type: GrantFiled: February 1, 1984Date of Patent: September 2, 1986Assignee: Westinghouse Electric Corp.Inventor: Thomas J. Gerlowski
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Patent number: 4526626Abstract: An anti-corrosion treatment process for protecting alloys containing chromium and cobalt and/or nickel against corrosion by superheated water, which consists of heating the alloy in contact with a solution containing EDTA and ferrous ions to within a temperature range that forms a thick, chromium oxide-rich glassy film over the surface of the alloy. Where the EDTA is present in the form of one of its disubstituted alkali salts, the solution is preferably heated to 200.degree. C. to 210.degree. C. under chemically reducing conditions. Further heating of the solution to 225.degree.-250.degree. C. improves the corrosion resistance of the film, by increasing its iron oxides content and converting at least part of its structure to microcrystalline. Films produced by the present process are found to have a very low nickel and cobalt content.Type: GrantFiled: September 7, 1983Date of Patent: July 2, 1985Assignee: United Kingdom Atomic Energy AuthorityInventor: John H. Carter
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Patent number: 4476047Abstract: A process is described for oxidizing pretreatment of chromium (III) oxide containing films, resulting from corrosion of base metal surfaces of piping systems and the like, to render the corrosion films more amenable to conventional chemical cleaning treatments. The process uses a dilute aqueous solution of an iron (VI) salt (FeO.sub.4.sup.2-).Type: GrantFiled: March 22, 1982Date of Patent: October 9, 1984Assignee: London Nuclear LimitedInventors: Paul J. Bonnici, Robert P. Denault
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Patent number: 4470951Abstract: A method of applying a descaling reagent comprising a one-electron reducing agent which is a low oxidation state transition metal ion in combination with a complexing agent to a surface to be treated to descale the surface which method comprises:(i) maintaining a low oxidation state transition metal ion either in solution under an inert atmosphere in a container made of or lined with an inert material or as a solid salt under an inert atmosphere;(ii) preparing a solution of the complexing agent and removing oxygen therefrom; and(iii) mixing the ingredients from steps (i) and (ii) either in situ in contact with the surface to be treated, or mixing the ingredients from steps (i) and (ii) prior to application to the surface to be treated under conditions whereby no substantial decomposition of the so-formed reagent occurs.Type: GrantFiled: July 28, 1981Date of Patent: September 11, 1984Assignee: Central Electricity Generating BoardInventors: David Bradbury, Timothy Swan, Michael G. Segal
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Patent number: 4410486Abstract: Nuclear reactor with a hydrogen-containing liquid coolant loop having an expansion tank for the coolant, a high pressure pump having a suction side and feeding coolant taken from the loop back into the loop after purification, a line bypassing the expansion tank and being connected to the suction side of the high-pressure pump, and means for introducing hydrogen into a liquid-filled section of the loop on the suction side of the high-pressure pump, including a liquid jet compressor for transporting hydrogen into the coolant.Type: GrantFiled: November 26, 1980Date of Patent: October 18, 1983Assignee: Kraftwerk Union AktiengesellschaftInventors: Edgar Schick, Peter Wisniewski
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Patent number: 4398967Abstract: Structural components of nickel-containing alloys within molten alkali metal systems are protected against corrosion during the course of service by dissolving therein sufficient aluminum, silicon, or manganese to cause the formation and maintenance of a corrosion-resistant intermetallic reaction layer created by the interaction of the molten metal, selected metal, and alloy.Type: GrantFiled: November 3, 1980Date of Patent: August 16, 1983Inventors: Jackson H. DeVan, James E. Selle
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Patent number: 4374083Abstract: Nuclear reactor with a liquid coolant loop having a volume control surge tank for the coolant disposed in the loop, and a high pressure pump disposed in the loop for feeding coolant taken from the loop back into the loop after purification. A line bypassing the volume control surge tank and having an end connected to the suction side of the high-pressure pump, and a feed-in for introducing hydrogen into a liquid-filled section of the loop on the suction side of the high-pressure pump.Type: GrantFiled: June 26, 1979Date of Patent: February 15, 1983Assignee: Kraftwerk Union AktiengesellschaftInventors: Hans Deinlein, Gottfried Kummer
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Patent number: 4364900Abstract: In pressurized water-cooled nuclear reactors, the formation of deposits on surfaces in the core of the reactor, e.g. on fuel sheaths, is suppressed by maintaining in the circulating pressurized water, a high concentration of ammonia ranging from about 120 to about 200 mg NH.sub.3 /kg water. Crevice corrosion of the fuel sheaths is avoided, even under localized boiling conditions, since the pH never attains a corrosively high level. The crevice corrosion danger with lithium can be reduced by replacing part of the lithium with ammonia.Type: GrantFiled: May 17, 1978Date of Patent: December 21, 1982Assignee: Atomic Energy of Canada LimitedInventor: Kenneth A. Burrill
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Patent number: H800Abstract: A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.Type: GrantFiled: April 20, 1989Date of Patent: July 3, 1990Assignee: The United States of America as represented by the United States Department of EnergyInventors: Edward C. Beahm, William E. Shockley