Abstract: A method and system for electrochemically measuring the sensitization to stress corrosion cracking of small pipes of plant structural members in a very short period of time. A micro electrochemical cell for measuring the sensitization is movably disposed within a BWR plant ICM housing or an instrumentation pipe. An electrochemical instrumentation system for performing the electrochemical potential variation such as pulse voltammetry and a remote control system for remotely controlling the electrochemical cell are provided.

Abstract: The invention is of a method for treating the primary cooling medium of a pressurized water nuclear reactor by controlling its efficiency through the H.sub.3 BO.sub.3 content in the cooling medium. Hydrazine hydrate (N.sub.2 H.sub.4 .multidot.H.sub.2 O) is continuously fed to the coolant of a reactor which is charged for energy generation, to such an extent that its content equals 5.10.sup.-6 to 5.10.sup.-2 g/kg coolant medium as well as KOH and/or LiOH which corresponds to the alkaline properties. KOH in an amount of 80 to 56 mg/kg cooling medium with respect to the amount of H.sub.3 BO.sub.3 in a range of 20 to 0 g/kg cooling medium and the excess hydrogen is removed from the system leaving a maximum amount of hydrogen in the coolant medium of 100 n.multidot.ml/kg.

Abstract: A method and an apparatus for estimating the remaining service life of an object by measuring the physical quantity of a sample and which are applicable to a nuclear reactor. A plurality of model samples are experimentally prepared by preliminarily disposing a material having substantially the same composition as the object to be subjected to the estimation in an environment substantially the same as the object and measuring the physical quantities of the model samples in relation with exposure times. From this experiment, a relationship between the exposure time and the physical quantity under such an environment is obtained. Further, a critical exposure time which will cause an unstable fracture of a material of an actual sample, which is made of a material substantially the same as the object and placed in substantially the same environment as the object, is preliminarily obtained from the relationship between the exposure time and the physical quantity for the model samples.

Abstract: A method for treating the primary coolant of a pressure water reactor by controlling its efficiency through the H.sub.3 BO.sub.3 content in the coolant is described. Hydrazine hydrate is continuously added to the coolant cycle of a nuclear reactor which is charged for energy generation in such amounts that its content is 5.multidot.10.sup.-6 to 5.multidot.10.sup.-2 g/kg coolant. Excess hydrogen is removed from the coolant leaving a content of no more than 100 n.ml/kg.

Abstract: A water jet peening method in which a pressurized water jet flow containing cavities is jetted through a nozzle having a velocity increasing orifice portion and a horn-like jetting hole formed continuously with the velocity increasing orifice portion to impinge against a surface of a metallic material immersed in water and to cause the cavities to collapse at the surface of the metallic member, and a tensile plastic deformation is caused in a surface layer of the metallic material by a local high pressure generated by the impingement and the collapse so that a residual tensile stress in the surface of the metallic member is reduced. In this method, the nozzle is vibrated so that vibration-induced cavities are formed in the vicinity of a nozzle wall surface, and the vibration-induced cavities are caused to impinge against the surface of the metallic member by the pressurized water jet flow containing cavities.

Abstract: A method for sputter coating the inside surface (30) of a fuel assembly tubular component (10) such as a control rod guide tube (200) with wear or corrosion resistant material. The steps include supporting the component tube in a fixture (12,14) and supporting a source tube (100,300) of e.g., wear resistant material, coaxially within the component tube, thereby defining a cylindrical annulus (24) between the tubes. The annular space is evacuated and backfilled with an inert working gas (26) such as argon, to a pressure sufficient to sustain a plasma discharge. The component tube is positively biased (36) as an anode, and the source tube is negatively biased (34) as a cathode, such that a plasma of the working gas is established in the annular space. A circumferential magnetic field is generated around the source tube to confine and shape the plasma whereby the source tube is bombarded with ions from the plasma substantially uniformly over the length of the source tube.

Abstract: An Fe-Cr-Mn alloy is disclosed which has the following composition by wt% and corrosion resistance of which is improved and deterioration in its strength is prevented at grain boundaries due to irradiation of high-energy particles such as neutrons: 5 to 40% of Mn, 5 to 18% of Cr, 2.0 to 12% of Al and the balance of Fe except for unavoidable impurities. In the alloy according to the present invention, Al is added to an Fe-Cr-Mn alloy by a restricted quantity as a main component element. As a result of the addition of Al, an alloy can be obtained in which lowering of concentration of Cr at grain boundaries due to irradiation of high-energy particles such as neutrons can be prevented or concentration of the solutes can be raised.

Abstract: An alkaline-permanganate process for chemically decontaminating oxidized metal surfaces wetted by primary water circulating in cooling loops of nuclear reactors maintains permanganate-containing primary water at a temperature of about 90.degree. C. and at a pH of 9-12 to oxidize the wetted surfaces. Oxalic acid is then added to the water and the oxalic acid-containing primary water is maintained at a temperature of at least about 90.degree. C. and at a pH of about 5-7 while it is circulated to destroy the permanganate ions and manganese dioxide.

Abstract: A method for enhancing the wear resistance of a tubular component (62) of a nuclear fuel assembly, including the first steps of supporting the component in an implantation chamber (16), removing ambient air from the chamber such as by a pump (56) and generating a plasma plume (28) of positively charged metal source material by establishing an electrical discharge arc which travels from a cathode (18) of said source material to an anode (24) of a different material. At least a portion of the plasma plume is passed through an electromagnetic duct (14) which filters constituents other than free, high energy source material ions out of the plume. The high energy source material positive ions are directed through the chamber onto the negatively charged component. The chamber can be backfilled with a reactive gas such as nitrogen which forms an ionic compound with the source material ions such as Zr or Ti, and the ionic compound such as ZrN or TiN implants in the component.

Abstract: Methods and apparatus for improving fretting resistance of zirconium alloy components formed into a shape for use in a nuclear reactor are disclosed in which at least a portion of the outer surface of a component is reacted with material selected from the group consisting of carbon, nitrogen, oxygen and combinations of the foregoing at a temperature below about 700.degree. C. to form a wear resistant layer on the surface of the component.

Abstract: A steam generator chemical solvent mixing system and method is provided. The chemical solvent mixing system includes a pump, having a discharge port fluidly connected to a discharge line and a suction port fluidly connected to a suction line. An upper level injector, including an injector nozzle extends through one upper access opening in the outer casing of a steam generator and extends into the annulus of the generator between the tube bundle shroud and the outer casing, the upper level injector being fluidly connected to the discharge port of the pump. A lower access eductor is provided, including an eductor nozzle extending through one lower access opening of the outer casing and adapted to discharge solvent through one passageway in the tube bundle shroud and into the tube bundle of the generator, the lower access eductor being fluidly connected to the discharge port of the pump.

Abstract: An ICM housing welded to a wall of a reactor pressure vessel in operation is provided with a molten metal layer containing 4 wt. % or more .delta. ferrite at a portion of an inner peripheral surface thereof which corresponds to a weld. A sleeve made of stainless steel is located at the competent portion of the inner peripheral surface of the ICM housing stainless steel so as to be molten by means of a TIG welding machine to form the molten metal layer. The molten metal layer prevents stress corrosion cracking of the ICM housing.

Abstract: In combination with a steam generator having a plurality of generator tube support plates, each generator tube support plate having a plurality of openings and a plurality of generator tubes, each tube passing through aligned openings in the support plates, a corrosion monitoring system is provided including a mockup probe, comprising a probe tube support plate having an upper side and a lower side and having substantially the same thickness and being constructed of substantially the same material as the generator tube support plates, having at least one opening of substantially the same size and shape as the openings of the generator tube support plates; at least one probe tube having an upper end and a lower end and having substantially the same diameter as the generator tubes and being constructed of substantially the same material as the generator tubes, the probe tube passing through the opening of the probe tube support plate; and wherein the mockup probe is adapted such that it may be inserted and seal

Abstract: An apparatus and method for monitoring corrosion to members within the core of a nuclear reactor, particularly fuel rod cladding. A sensor means is submerged inside the core of a nuclear reactor near the member or fuel rods. The sensor means is comprised of a generally cylindrical section having an outer surface that is subject to corrosion and radiation, and has a cross-sectional area A.sub.1. The sensor means additionally has a reference section subjected to radiation but not to corrosion, and having a cross-sectional area A.sub.2. At least one pair of first probes, separated by a length L.sub.1, is placed in electrical contact with the cylindrical section. At least one pair of second probes separated by a length L.sub.2, is placed in electrical contact with the reference section. A current is passed throughout the sensor means to produce a potential gradient in the cylindrical section and reference section.

Abstract: 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.

Abstract: The buildup of radioactive contaminants on the inside surface of light water reactor water systems is retarded by the use of a chromium coating of at least five hundred Angstroms on the surface exposed to the water system. The chromium coating is then passivated by exposure to an oxygen source for about five hours at a temperature between 150.degree. C. and 450.degree. C.

Abstract: 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.

Abstract: 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.

Abstract: Measurement values of conductivity of pH of water in the primary cooling water system of a boiling water atomic power plant are input through on-line and the measurement values of conductivity and pH at times of measurement when water quality changes are compared with values at the time of normal operation. Tendencies to increase or decrease the conductivity and pH are combined to prepare one diagnosis data, and causes of anomaly in progress in component apparatus members are discriminated and diagnosed by the diagnosis data. By using a correlation between logarithm of conductivity and pH in preparing the diagnosis data from combinations of conductivity and pH, causes of anomaly can be diagnosed more accurated.

Abstract: 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.

Abstract: 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.

Abstract: A unique and optimal method for assessing the feasibility of employing chemical decontamination processes to remove crud from nuclear reactor primary systems without adversely affecting the integrity of the system components or piping during further reactor operation is disclosed. Materials used to construct such components and piping are exposed to several cycles of simulated decontamination processing with a test loop constructed to simulate a range of full system decontamination process conditions. The material specimens are then removed and tested to assure that the particular decontamination processing system has no adverse effects on the materials used.

Abstract: An apparatus and method for monitoring corrosion to members within the core of a nuclear reactor, particularly fuel rod cladding. A sensor means is submerged inside the core of a nuclear reactor near the member of fuel rods. The sensor means is comprised of a generally cylindrical section having an outer surface that is subject to corrosion and radiation, and has a cross-sectional area A.sub.1. The sensor means additionally has a reference section subjected to radiation but not to corrosion, and having a cross-sectional area A.sub.2. At least one pair of first probes, separated by a length L.sub.1, is placed in electrical contact with the cylindrical section. At least one pair of second probes separated by a length L.sub.2, is placed in electrical contact with the reference section. A current is passed throughout the sensor means to produce a potential gradient in the cylindrical section and reference section.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Process for the radioactive decontamination of metal surfaces, particularly portions of the primary circuits of water-cooled nuclear reactors, characterized in that it comprises subjecting said surfaces to the successive stages of an oxidizing pretreatment with the aid of a solution of potassium permanganate KMnO.sub.4 and nitric acid, rinsing with demineralized water and then reducing treatment in a basic medium with the aid of a solution of alkali metal gluconate of formula HOH.sub.2 C--CHOH--CHOH--CHOH--CHOH--COOM, in which M is an alkali metal chosen from among Na and K, as well as soda NaOH.

Abstract: A method of decontaminating radio nuclide-contaminated corrosion products, which are sparingly soluble in acid, from primary system surfaces in reactors of the pressurized water reactor type and the boiler reactor type with hydrogen dosage and similar, by oxidation and concurrent dissolution in an acidic decontamination solution of the acid soluble corrosion products obtained by said oxidation. The characteristic feature of the method is that said oxidation is performed with Ce.sup.4+ ions, ozone and chromic acid in the presence of perhalogen acid, preferably perchloric acid, at a pH below 3.

Abstract: A containment cooling system utilizes a naturally induced air flow and a gravity flow of water over the containment shell which encloses a reactor core to cool reactor core decay heat in two stages. When core decay heat is greatest, the water and air flow combine to provide adequate evaporative cooling as heat from within the containment is transferred to the water flowing over the same. The water is heated by heat transfer and then evaporated and removed by the air flow. After an initial period of about three to four days when core decay heat is greatest, air flow alone is sufficient to cool the containment.

Abstract: A purifier for nuclear reactor cooling water, which contains, as an active ingredient,a titanium oxide-based solid solution of the formula (1)(Ti.sub.1-x Al.sub.x)O.sub.2 (1)wherein x is defined by 0<x<0.5, and/oran aluminum oxide-based solid solution of the formula (2)(Al.sub.1-y Ti.sub.y).sub.2 O.sub.3 (2)wherein y is defined by 0<y<0.5, and a method of purification of nuclear reactor cooling water, which comprises bringing nuclear reactor cooling water having a temperature of 100.degree. to 300.degree. C. into contact with the above purifier.

Abstract: 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.

Abstract: For determining the content and the chemical composition of particulate compounds in a liquid flow (15), the particulate compounds are collected on a filter (20) in a container (19) of a material which is permeable to microwaves. When carrying out the determination, samples of a fixed size of the liquid in the flow are supplied batchwise to the container on one side of the filter via an openable and a closable connection (16, 17) between the liquid flow and the container. At the same time, liquid from each liquid sample supplied batchwise, which has passed through the filter, is discharged from the container via an openable and a closable outlet (30, 31) on the other side of the filter.

Abstract: A method of restraining a diffusion of tritium and an apparatus for same are disclosed. The method includes the step of disposing a hydrogen-absorbing metal in a tritium passage in a direction of diffusion of tritium so that the hydrogen-absorbing metal absorbs tritium to be diffused. The apparatus includes a hydrogen-absorbing metal surrounding a device of a fast breeder reactor. The tritium to be diffused can be readily captured. An arrangement of capturing the tritium permeating the device is simplified in the present invention.

Abstract: A steam turbine preservative and method of preserving steam turbine components involves the application of an amine polymer as a non-aqueous layer to the surfaces of such components. An organic solvent is mixed with the amine polymer to adjust its application viscosity.

Abstract: A sheath for a nuclear reactor control rod consists of chromium nickel stainless steel. It is protected against friction wear by nitridation over a depth of from 15 to 50 .mu.m obtained by an electric discharge in a nitrogen containing atmosphere.

Abstract: An absorber rod for nuclear reactors with a pile of spherical fuel elements, which is inserted directly into the pile, in order to affect the prevailing neutron flux by absorber material located in an annular gap between two concentric cylindrical rod elements. The absorber rod has concentric rod elements arranged in pairs, a common rod tip and common connecting pieces. The rod elements are cooled by flow of gas and the inner cylindrical rod element performs the support function, i.e., it absorbs and transmits forces and moments originating in the movements of the rod during insertion and extraction.

Abstract: For improving the corrosion resistance of the sheaths of fuel rods used in water cooled and moderated reactors, part at least of the outer surface of the sheath is coated with a dense and adhering carbon layer having a thickness of from 0.1.mu. to 5.mu.. The layer may be deposited by radiofrequency reactive sputtering in a lower alkyl containing atmosphere.

Abstract: A process for improving resistance of pressure vessel shells, tubesheets, tubes, pipes, pipe fittings and machine parts to stress corrosion cracking comprising heating at least those portions of such bodies subject to danger by stress corrosion cracking to a critical elevated themperature level, cooling at least the surface portions of the metal body subject to stress corrosion cracking and then permitting such treated portions of the metal body to come to ambient temperature.

Abstract: A method of providing a nuclear steam supply system that is constructed to include a barge or flotation base as an integrated portion thereof. The system is tested for operability and safety at the factory and then towed along navigable coastal or inland waterways, or overseas to foreign locations, to a prepared foundation site at its point of use. The overall unit is so constructed and arranged as to permit the removal of top and side portions to permit passage under low bridges and through narrow locks without requiring disassembly of safety class piping and wiring. The method further provides for a complete nuclear power plant constructed on multiple barges at a separate factory site in parallel with plant site preparation, i.e., in estuaries or caves.

Abstract: Irradiation assisted stress corrosion cracking occurring in the metallic core components of light water nuclear reactors is reduced by the use of austenitic stainless steel alloys containing a maximum of about 0.03% nitrogen, as well as about 0.025% to about 0.067% carbon, about 1.5% to about 2.0% manganese, a maximum of about 0.005% phosphorus, a maximum of about 0.05% silicon, and a maximum of about 0.005% sulfur.

Abstract: The present invention is concerned with a method of reducing radioactivity in a nuclear plant by preliminarily forming oxide films on the surfaces of metallic structural members to be in contact with high-temperature and high-pressure reactor water containing radioactive substances before said metallic members are exposed to said reactor water. The method is characterized by the steps of subjecting said structural members to a first-step oxidation treatment of heating said structural members in an environment of a high temperature, and further subjecting the thus treated structural members to a second step oxidation treatment of heating said treated structural members in an environment having a higher oxidizing capacity than that of said environment in said first-step oxidation treatment to form a denser oxide film than an oxide film obtained in said first step oxidation treatment. According to the present invention, radioactivity in the nuclear plant can be reduced remarkably.

Abstract: 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.

Abstract: A process for improving resistance of control rod guide tube split pins in nuclear reactors to stress corrosion cracking comprising heating the split pin to a critical elevated temperature level, cooling at least the surface portions of the split subject to stress corrosion cracking and then permitting the split pin to come to ambient temperature.

Abstract: Process for the elimination of corrosion products formed on the tube plate and in the gaps between the tubes and the spacer plates of a steam generator of a pressurized water nuclear reactor, in order to prevent the appearance of a corrosion phenomena, which can lead to necking or denting of tubes by oxide growth.The process consists of reacting with said oxides at between 50.degree. and 100.degree. C., an aqueous solution containing 6 to 8% gluconic acid, 3 to 5% citric acid, approximately 0.5% of a corrosion inhibitor and ammonia until a pH between approximately 3 and 9.5 is obtained.

Abstract: A method is set forth of passivating at least a portion of a surface of a stainless steel member to retard buildup of radioactive materials on such surface portion. The surface portion is preferably polished until it is substantially featureless at 100 times magnification. The polished surface is exposed to a gaseous oxygen source at a temperature of 150.degree. C. to 450.degree. C. for at least about five hours. When a pipe passivated as set forth above is utilized in a water system of a light water nuclear reactor, radioactive buildup on the surface is significantly reduced as compared to pipes which have been passivated by exposure to liquid during the passivating process.

Abstract: A corrosion preventing device for use in an in-pile structure of a helium gas-cooled reactor for removing gaseous oxidating components from a primary cooling gas in a pressure vessel of the reactor to thus prevent oxidation of graphite members of the reactor pile. An oxidation product consuming member is provided in series with a primary cooling gas supply pipeline or a bypass pipeline thereof along with a device for heating the oxidation product consuming member. The oxidation product consuming member may be a single cylindrical member or a bundle of rods having a large number of through holes formed therein in a honeycomb pattern in the lengthwise direction thereof or a large number of balls. The material of the oxidation product consuming member should have a high affinity for oxidizing impurities at elevated temperatures. Preferably, the material of the oxidation product consuming member is carbon or graphite.

Abstract: In a method of inhibiting or avoiding intermixing of the atmosphere which exists in a closed nuclear reactor containment space with a gaseous substance present in the same space a change in density of the atmosphere is induced in either lower or upper area of the space such that a stable atmosphere stratified into superimposed layers is formed in that space due to the change in density.

Abstract: A method for treating the surface of finished parts formed of zirconium alloys for nuclear reactor fuel assemblies with an oxidizing agent, includes heating the finished parts in an autoclave and subjecting the finished parts to an oxidizing agent sufficient to generate oxygen in atomic form and to form a substantially hydrogen-impervious surface layer of oxide at least on the surface portions of the finished parts which are subjected to water or steam in the nuclear reactor.

Abstract: A method of inhibiting corrosion of carbon steel piping of condensate and feed water systems in a power generating plant, characterized by continuing the water in said piping to flow after also said plant has been shut down until it is restarted up and by keeping the specific electric conductivity of flowing water at 0.5 .mu.S/cm or less.

Abstract: 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.