A valve assembly includes a flange connected to a vessel penetration of a reactor pressure vessel of a nuclear reactor. A valve is disposed inside the flange or protrudes from the flange into the vessel penetration. The valve includes a valve seat and a movable valve member positioned so that pressure inside the reactor pressure vessel urges the movable valve member against the valve seat to close the valve. The valve assembly further includes a plenum having an inlet via which the plenum can be pressurized to apply pressure to the movable valve member that urges the movable valve member away from the valve seat to open the valve. The plenum may be defined in part by a surface of the movable valve member. The valve assembly preferably does not include a valve actuator.

Methods and systems for removing impurities from a molten salt stream are provided. A molten salt stream is provided that comprises a mixture of compounds selected from the group consisting of LiF, BeF.sub.2, and NaF, and ZrF.sub.4. The molten salt stream is flowed through a loop that may contain a precipitation filter, electrochemical potential, and/or a sparger, which thereby remove impurities in the molten salt stream. Various physical methods and apparatus are used to control the ability to remove impurities from the molten salt stream based on temperature, solubility, and general chemistry control.

An in-line dissolved gas removal membrane-based apparatus for removing dissolved hydrogen and fission gases from the letdown stream from a reactor coolant system.

An in-line dissolved gas removal membrane-based apparatus for removing dissolved hydrogen and fission gases from the letdown stream from a reactor coolant system.

Disclosed are an apparatus and a method for purifying reactor coolant radioactive material and adjusting the pH of the reactor coolant, to replace and overcome the disadvantages of the purification and Li adjustment of a reactor coolant, by conventional ion-exchange resins; to concentrate, store and reuse Li.sup.7, which is naturally produced in a nuclear reactor during power operation, without injecting expensive LiOH obtained by removing Li.sup.6 and concentrating only Li.sup.7; or to solve the problem that lithium (Li.sup.+) ions used as a pH adjusting agent are removed together with radioactive metal ion materials which is and adverse effect occurring when the lithium ions are applied to a reactor coolant purification apparatus.

A filtering device, a system including the filtering device, and methods of using the filtering device. The filtering device is configured to be arranged inside a fluid to be filtered and comprising at least one main filter and a filter holder supporting the main filter. The filtering device is configured to be moved inside the fluid, in such a way that when the filtering device is moved in a first movement direction, at least one part of the fluid passes through the main filter in a first filtering direction. The filtering device is configured in such a way as to prevent the fluid from passing through the main filter in a second filtering direction opposite to the first filtering direction when the filtering device is moved in a second movement direction opposite to the first movement direction.

A filtering device, a system including the filtering device, and methods of using the filtering device. The filtering device is configured to be arranged inside a fluid to be filtered and comprising at least one main filter and a filter holder supporting the main filter. The filtering device is configured to be moved inside the fluid, in such a way that when the filtering device is moved in a first movement direction, at least one part of the fluid passes through the main filter in a first filtering direction. The filtering device is configured in such a way as to prevent the fluid from passing through the main filter in a second filtering direction opposite to the first filtering direction when the filtering device is moved in a second movement direction opposite to the first movement direction.

Disclosed are an apparatus and a method for purifying Li.sup.7 ions from reactor coolant radioactive material and adjusting pH of the reactor coolant. The apparatus comprises a radioactive metal ion recovery unit comprising a first negative electrode member having a negative (?) electrode connected thereto and a first positive electrode member having a positive (+) electrode connected thereto, and an Li ion separation/concentration unit. The radioactive metal ion recovery unit is configured such that the reactor coolant discharged from the non-generative heat exchanger passes between the first negative electrode member and the first positive electrode member The Li ion separation/concentration unit comprises a second positive electrode member having a second positive (+) electrode connected to one side of the Li ion separation/concentration unit, a second negative electrode member having a negative (?) electrode connected to the other side of the Li ion separation/concentration unit, and a cation-exchange membrane provided between the second positive electrode member and the second negative electrode member and configured to pass a cation therethrough. The Li ion separation/concentration unit is configured such that the reactor coolant that passed through the radioactive metal ion recovery unit passes between the second positive electrode member and the cation-exchange membrane Accordingly, Li.sup.7 ions, produced in the reactor coolant and passed through the cation-exchange membrane, move toward the second negative electrode member and are separated. The apparatus further comprises an Li.sup.7 concentration tank configured to concentrate Li.sup.7 in a recycling process in which Li.sup.7 separated from the Li ion separation/concentration unit is recycled again to the Li ion separation/concentration unit.

Disclosed are an apparatus and a method for purifying Li.sup.7 ions from reactor coolant radioactive material and adjusting pH of the reactor coolant. The apparatus comprises a radioactive metal ion recovery unit comprising a first negative electrode member having a negative (?) electrode connected thereto and a first positive electrode member having a positive (+) electrode connected thereto, and an Li ion separation/concentration unit. The radioactive metal ion recovery unit is configured such that the reactor coolant discharged from the non-generative heat exchanger passes between the first negative electrode member and the first positive electrode member The Li ion separation/concentration unit comprises a second positive electrode member having a second positive (+) electrode connected to one side of the Li ion separation/concentration unit, a second negative electrode member having a negative (?) electrode connected to the other side of the Li ion separation/concentration unit, and a cation-exchange membrane provided between the second positive electrode member and the second negative electrode member and configured to pass a cation therethrough. The Li ion separation/concentration unit is configured such that the reactor coolant that passed through the radioactive metal ion recovery unit passes between the second positive electrode member and the cation-exchange membrane Accordingly, Li.sup.7 ions, produced in the reactor coolant and passed through the cation-exchange membrane, move toward the second negative electrode member and are separated. The apparatus further comprises an Li.sup.7 concentration tank configured to concentrate Li.sup.7 in a recycling process in which Li.sup.7 separated from the Li ion separation/concentration unit is recycled again to the Li ion separation/concentration unit.

Some embodiments include an chemical separation mechanism for a molten salt reactor where the molten salt may include fission products. In some embodiments, the chemical separation mechanism includes a molten salt receptacle with a molten salt disposed within, a solvent receptacle having a solvent disposed within; an electrode; and an electrode mechanism. In some embodiments, the electrode mechanism may be configured to submerse the electrode into the molten salt receptacle such that a chemical reaction occurs between the electrode and one or more of the fission products in the molten salt. In some embodiments, the electrode mechanism may submerse the electrode into the solvent receptacle such that a chemical reaction occurs resulting in one or more of the fission products being deposited into the solvent.