Abstract: A nuclear facility includes a fuel element pool which is filled with a cooling liquid. A fuel element rack, which is disposed in the fuel element pool, includes compartments for receiving fuel elements. The fuel elements received in the compartments are in direct contact with the cooling liquid in the fuel element pool. At least one cooling element is disposed in one of the compartments instead of a fuel element. The cooling element acts as a heat exchanger through which a coolant can flow, the cooling element is connected into a cooling circuit and the cooling element is immersed in the cooling liquid.

Abstract: A method of producing radionuclides from irradiation targets in a nuclear reactor uses at least one instrumentation tube system of a commercial nuclear reactor. Irradiation targets and dummy targets are inserted into an instrumentation finger and the irradiation targets are activated by exposing them to neutron flux in the nuclear reactor core to form a radionuclide. The dummy targets hold the irradiation targets at a predetermined axial position in the reactor core corresponding to a pre-calculated neutron flux density sufficient for converting the irradiation targets to the radionuclide. Separating the dummy targets from the activated irradiation targets includes exposure to a magnetic field to retain either the dummy targets or the activated irradiation targets in the instrumentation tube system and release the other one of the activated irradiation target or the dummy target from the instrumentation tube system. An apparatus adapted to the above method is also provided.

Abstract: The invention provides a method of preparing irradiation targets for radioisotope production in instrumentation tubes of a nuclear power reactor, the method comprising the steps of: providing a powder consisting of an oxide of a rare earth metal having a purity of greater than 99% and, optionally, an organic binder; pelletizing the powder and optionally the organic binder to form a substantially spherical green body having a diameter of from between 1 to 10 mm; and sintering the spherical green body in solid phase at a temperature of at least 70 percent of a solidus temperature of the rare earth metal oxide powder and for a time sufficient to form a round sintered rare earth metal oxide target having a sintered density of at least 80 percent of the theoretical density.

Abstract: A sample container, sampling system and operating methods permit representative sampling from a liquid phase or boiling liquid, a gaseous phase, a containment sump, containment atmosphere, or condensation chamber of a nuclear power plant following a severe accident. A sample container obtaining an environmental sample includes an outer chamber surrounded by an outer container wall, being directly fluidically connected to the environment through a passage opening in the outer container wall and being fillable with a liquid at least in a base region. An inner chamber surrounded by an inner container wall is fluidically connected to the base region through a passage opening in the inner container wall, has connections for sampling and conveyor medium lines and is otherwise pressure and media tightly sealed from the environment. A pneumatically or hydraulically actuatable closure device for the passage opening between the outer and inner chambers has an actuation medium line connection.

Abstract: A method for a multielement analysis via neutron activation. The method includes generating fast neutrons with an energy in the range of 10 keV to 20 MeV and moderating the neutrons, irradiating the sample with the neutrons, and measuring the gamma radiation emitted by the irradiated sample using a detector to determine at least one element of the sample. The sample continuously irradiated in a non-pulsed fashion. The measurement is implemented during the irradiation. The determination of the at least one element includes an evaluation of the measured gamma radiation. The sample is subdivided into individual partitions and the measurement is implemented using a collimator. The evaluation includes a spatially resolved and energy-resolved determination of the neutron flux within the respective partition of the sample and calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a single partition of the sample by an approximation method.

Abstract: The disclosure relates to a device for checking a fuel rod comprising a testing container having first and second chambers, a first checking device arranged in the testing container, wherein the testing container has at least one inlet opening, at least one outlet opening, and an insertion opening for inserting the fuel rod into the second chamber, and wherein a valve is arranged in a connecting channel connecting the first and the second chamber. A method is disclosed for checking a fuel rod in a water-filled basin of a submerged nuclear plant having such a device, wherein the fuel rod is inserted into the second chamber of the testing container through the insertion opening while the valve is closed, wherein a fluid is fed in via the at least one inlet opening, and wherein the valve is opened in order to check the fuel rod with the first checking device.

Abstract: An irradiation target processing system for insertion and retrieving irradiation targets into and from an instrumentation tube in a nuclear reactor core comprises, a target retrieving system, target insertion system and transport gas supply system, mounted on a movable support, wherein: the target retrieving system comprises a target exit port coupled to a target storage container and exhaust system; the target insertion system comprises a target filling device, target retention tubing with target supply junction connectable to the instrumentation tube, and a target diverter coupled to the target filling device, target retention tubing and target retrieving system; and the transport gas supply system comprises a first gas supply tubing coupled to the exit port of the target retrieving system, a second gas supply tubing coupled to a junction for supplying gas to the instrumentation tube, and a transport gas supply junction coupled to the first and second gas supply tubing.

Abstract: A pressure-relief system for a containment of a nuclear plant has a pressure-relief line which is led through the containment and is closed by a shutoff device, and a wet scrubber being switched into the pressure-relief line lying outside the containment, for the pressure-relief gas flow developing in the pressure-relief operating mode with the shutoff device being open. An effective, reliable operation of the wet scrubber with a compact structural configuration is made possible. This is achieved by a reservoir, arranged in the containment or fluidically connected therewith such that an overpressure, as compared with the outer environment, present in the containment, is transferred to the reservoir, and a feeding line which is led from the reservoir to the wet scrubber and can be closed by a shutoff device, for feeding a liquid active as a scrubbing liquid from the reservoir to the wet scrubber.

Abstract: Irradiation targets, useful in preparing radioisotopes by exposure of the target to a neutron flux in instrumentation tubes of a nuclear power reactor, are prepared by a method comprising the steps of: providing a powder of an oxide of a rare earth metal having a purity of greater than 99%; consolidating the powder in a mold to form a round green body having a green density of at least 50 percent of the theoretical density; and sintering the spherical green body in solid phase at a temperature of at least 70 percent of a solidus temperature of the rare earth metal oxide powder to form a round sintered rare earth metal oxide target having a sintered density of at least 80 percent of the theoretical density.

Abstract: A device for repairing damage to a bottom of a container filled with water is disclosed. The device comprises a guiding device, which can be placed on the bottom of the container and which has a centering device for centering the guiding device between wall sections of the bottom elements. The devices further comprises a fixing device for fixing the guiding device on the bottom of the container, a carrier, which can be guided along the guiding device and on which at least one pivot arm is arranged, and an accommodating element arranged at a free end of the pivot arm, for accommodating adhesive, with which part of a wall section of the bottom elements can be covered.

Abstract: The invention relates to a device for performing a leak test on a fuel rod capsule, which contains at least one fuel rod and test gas, which device comprises a test container, which is designed to accommodate at least one fuel rod capsule and can be lowered into a pool of a nuclear plant flooded with water. According to the invention, a mass spectrometer is fluidically connected to the interior of the test container in such a way that a gas flow can be fed to the mass spectrometer in order to sense the concentration of the test gas that has diffused into the test container from the fuel rod capsule.

Abstract: A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises: an oxidation step, comprising at least one acidic oxidation step and at least one alkaline oxidation step wherein metal oxides and radioisotopes on the metal surfaces are contacted with aqueous permanganate oxidant solutions; followed by a decontamination step wherein an aqueous solution comprising oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid glyoxylic acid or mixtures thereof is used to dissolve at least part of the metal oxides and radioisotopes; and a cleaning step wherein radioisotopes are immobilized on an ion exchange resin; wherein at least one treatment cycle includes a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100° C.

Abstract: A method for encapsulating a fuel rod or a fuel rod section in a container includes inserting the fuel rod or fuel rod section into the container. One of the ends of the container is connected to a purging-gas line. The container is dehydrated and purged by use of a purging gas. The ends of the container are connected to a bypass line in such a way that a closed gas circuit is produced and a hot gas is circulated in the gas circuit until the absolute moisture content reaches an end value at which the absolute moisture content no longer rises. The container is disconnected from the gas circuit and subsequently the container is closed in a fluid-tight manner at both ends.

Abstract: A method for conditioning the circulatory system (1) of a power plant is especially suited for a nuclear power plant. An amine, which is a film-forming agent, is metered into the working medium circulating in the circulatory system. The film-forming agent forms a hydrophobic film on the surfaces of the circulatory system. During the process, the concentration of the film-forming agent is monitored in at least one measuring point by way of measurement, and metering of the film-forming agent is stopped once its concentration in the working medium has reached a value of 1 ppm to 2 ppm in at least one measuring point M1.

Abstract: A nuclear plant has a containment shell and a pressure relief line passing out of the containment shell and sealed by a shut-off valve, and through which a pressure relief flow can flow during relief operation, such that it is configured for particularly reliable management of critical scenarios where there is a considerable pressure increase within the containment shell at the same time as the release of hydrogen and/or carbon monoxide. A gas flow treatment device is provided upstream from the respective pressure relief line, and contains a flow duct and has a lower inflow opening and an upper inflow/outflow opening. Catalytic elements for eliminating hydrogen and/or carbon monoxide are arranged in the flow duct above the lower inflow opening. During a critical fault, the flow duct is flowed through from bottom to top by a gas mixture present in the containment shell by the principle of natural convection.

Abstract: A method and a corresponding device for the pressure relief of a nuclear power plant having an outlet for a relief flow. The relief flow is guided out of a containment into the atmosphere via a relief line provided with a filter system. The filter system has a filter chamber with a filter-chamber inlet and outlet and a sorbent filter arranged therebetween. The relief flow is guided in a high-pressure section of the relief line past the filter chamber, with the latter being heated, and the relief flow is expanded at the end of the high-pressure section and dried. In order for efficient retention of iodine-containing organic compounds, the relief flow is guided through a bed filter, guided in a superheating section past the high-pressure section of the relief line and in the process is heated, guided in this state directly thereafter through the filter chamber having the sorbent filter.

Abstract: A pressure-relief system for the containment of a nuclear power facility allows reliable operation of a wet scrubber for the pressure relief flow with a simultaneously compact structural design. The pressure relief system has a pressure relief line guided through the containment and can be closed by a shut-off valve, a wet scrubber arranged in a portion of the pressure relief line located inside the containment, for the pressure relief flow which forms in the pressure-relief mode when the shut-off valve is open, a reservoir arranged inside the containment and is fluidically connected to the remaining inner space of the containment such that any overpressure, with respect to the surroundings outside the containment, prevailing in the containment is transferred at least in part to the reservoir, and a supply line leading from the reservoir to the wet scrubber for supplying the wet scrubber with fluid from the reservoir.

Abstract: A method for treating waste water from the decontamination of a metal surface in a primary coolant circuit of a nuclear reactor comprises discharging a predetermined amount of an oxidation solution from the primary coolant circuit into a reduction zone connected to the primary coolant circuit and reacting the oxidation solution with a reducing agent to form a reaction solution that is freed of oxidizing agent, and passing the reaction solution over an ion-exchange resin in order to form a desalinated solution, and returning the desalinated solution to the primary coolant and/or disposing of the desalinated solution. A waste water treatment apparatus for carrying out the method is also provided.

Abstract: A process for the recovery of a radioisotope from a waste resin of a nuclear power plant comprises the steps of: a) treating a waste resin loaded with at least one radioisotope with an organic acid or alkaline compound to release the at least one radioisotope and to obtain a process solution containing the at least one radioisotope; b) separating the at least one radioisotope from the process solution through a reaction specific to the radioisotope so as to obtain a treated process solution depleted of the at least one radioisotope, wherein said depleted process solution comprises the organic acid or alkaline compound and optionally a non-reacted radioisotope; c) reacting the organic acid or alkaline compound in the depleted process solution from step b) by thermal and/or photochemical oxidation to form gaseous reaction products; and d) reloading the waste resin with the reacted process solution from step c) to bind the non-reacted radioisotope on the waste resin.

Abstract: A method for testing whether fuel rods of fuel assemblies resting on a working base and under water, of a nuclear reactor are leaking is disclosed. The method includes heating at least one first fuel assembly of a first division of fuel assemblies for driving radioactive fission products out of a defective fuel rod contained in the first fuel assembly. The first fuel assembly is continuously tested by extracting samples of water and continuously degassing the water removed from an area around the first fuel assembly even during the heating resulting in gas. A radioactivity of gaseous fission products released in the gas is continuously recorded. A fuel assembly belonging to a second division of fuel assemblies is heated only if the first fuel assembly belonging to the first division of fuel assemblies has been tested. An apparatus for implementing the method is also disclosed.