The present invention provides a family of dark quenchers, termed Black Hole Quenchers (“BHQs”), that are efficient quenchers of excited state energy but which are themselves substantially non-fluorescent. Also provided are methods of using the BHQs, probes incorporating the BHQs and methods of using the probes.

The present disclosure relates to an azoquinone compound represented by formula (1) below. In formula (1), R1 to R4 are identical or different and each represents a hydrogen atom, a C1 to C6 alkyl group or a C6 to C12 aryl group, and Ar represents a C6 to C12 aryl group.

Described herein are pharmaceutical compositions and medicaments, and methods of using such pharmaceutical compositions and medicaments in the treatment of cancer.

A hypoxia contrast medium including nitroimidazole-amino acid chelate with a positively charged radioactive nuclide, a preparation method and use thereof. The contrast medium can be used in imaging cerebral thrombosis, tumors or other diseases such as ulceration, thrombosis, and so on.

The present invention relates to a method of differentially diagnosing different types of dementia. In particular, the method relates to the use of specific SPECT tracers for differentially diagnosing Alzheimer's disease, Lewy-Body Dementia, and Frontotemporal Dementia.

A method and apparatus for transporting syringes containing radioactive material. The apparatus includes a radiopharmaceutical pig having an inner chamber in which a sharps container can be secured. The sharps container has a housing and an attachable cap. The method includes assembling the radiopharmaceutical pig so that the chamber of the radiopharmaceutical pig contains the syringe in the sharps container housing. The radiopharmaceutical pig is disassembled, where upon the syringe is removed, discharged, and then replaced in the sharps container housing. The cap of the sharps container is affixed to the housing of the sharps container, thus enclosing the contaminated syringe therein. The radiopharmaceutical pig is assembled so that its chamber contains the sharps container and the syringe. The radiopharmaceutical pig is transported to a disposal area, where it is disassembled and the sharps container containing the syringe is placed in a particular disposal container.

A method for removing radioactive contaminants from a given surface. An acidic solution having a pH of less than 3.0, and preferably less than 1.5, of a complex substituted keto-amine, and a mixture of a saturated and unsaturated lower alcohol (e.g. isopropyl alcohol and propargyl alcohol), and concentrated acid is applied to a contaminated surface. The solution is left on said surface for a time sufficient to remove the radioactive contaminants into the acidic solution and then removed. The acidic solution containing the radioactive contaminants is preferably neuralized by an alkaline material to a pH of between 5.5 and 9.0. Removal of thorium contamination from railcars is one useful application of the invention. The method of the present invention has the effect of removing substantially all of the radioactive contaminants from a previously contaminated surface.

A preferred embodiment may generally be construed as providing a method for storing fissile material, such as spent nuclear fuel (SNF), and includes the steps of: providing a storage container configured to receive the fissile material therein; and applying a coating to a surface of the storage container. Preferably, the coating is formed, at least in part, of a neutron-absorbing material and is adapted to reduce neutron multiplication and/or provide a shielding of the fissile material received within the storage container. Systems also are provided.

An apparatus and method for transporting radiopharmaceutical substances. The apparatus comprises a radiation shielding pig having an elongated sidewall that extends between two ends and that defines an elongated, interior chamber. The sidewall is thinner than each of the ends. A radiation shield defines at least one cavity. The shield has two open ends and a central area between the open ends that is thicker than each of the two open ends. Also, a method of assembling and disassembling the apparatus includes, placing a syringe filled with a radiopharmaceutical substance into the pig; placing the pig containing the filled syringe in the radiation shield; placing the pig and the shield into an ammunition can for transporting the radioactive substance contained in the syringe.

A method for removing radioactive contaminants from a given surface. An aqueous solution having a wetting agent and a complex substituted keto-amine is provided. The solution is left on the surface for a time sufficient to remove the radioactive contaminants into the aqueous solution which is then removed. Depending on the type and condition of the surface, a concentrated acid may be added to the aqueous solution to aid in the contaminant removal process. In such a case, a pH of less than 3.0, and preferably less than 1.5 is maintained. If a concentrated acid is used, the acidic solution containing radioactive contaminants is preferably neutralized by an alkaline material to a pH of between 5.5 and 9.0. Removal of thorium contamination from railcars is one useful application of the invention. The method of the present invention has the effect of removing substantially all of the radioactive contaminants from a previously contaminated surface.

A spent fuel reprocessing method including the steps of partitioning U and Pu(III) in a solvent by solvent extraction and subsequently polishing the solvent in a neptunium rejection operation for removing Np therefrom. The solvent obtained from the neptunium rejection operation (the polished solvent or NpA solvent product) is then recycled to a U/Pu partitioning operation. The method enables a reduction in solvent feed and solvent effluent volumes.

The present invention relates to a process to dissolve plutonium or a plutonium alloy, by placing it in contact with an aqueous dissolution mixture, wherein said dissolution mixture comprises nitric acid, a carboxylic acid with complexing properties with respect to plutonium, and a compound comprising at least one —NH2 radical such as urea. The invention also relates to a process to convert plutonium or a plutonium alloy into plutonium oxide and to manufacture nuclear fuel from said oxide.The invention particularly applies to the dismantling of plutonium contained in nuclear weapons with a view to its use in civilian nuclear reactors, particularly in the form of MOX fuel.

A method for removing a wide variety of radioactive contaminants from a contaminated surface sufficient for the surface to be classified as a low-level waste or as free release. Contaminated surfaces may be classified as Class C, Class B, Class A, or high-level radioactive wastes prior to treatment. An aqueous solution having a wetting agent and a complex substituted keto-amine is provided. The aqueous solution is left on the surface for a time sufficient to remove the radioactive contaminants into the aqueous solution which is then removed. Depending on the type and condition of the surface, an acid may be added to the aqueous solution to aid in the contaminant removal process. However, typical metals surfaces may often be treated effectively without the use of concentrated acids or with dilute concentrations of such acids. The method of the present invention has the effect of removing substantially all of the radioactive contaminants from a variety of previously contaminated surfaces.

The present invention concerns a process for dissolving ruthenium deposits that are present on a surface and a process for decontaminating the internal circuits of nuclear fuel reprocessing plants using the said dissolution process. The process according to the invention comprises bringing the said surface into contact with an aqueous solution of perruthenate, with the said aqueous solution having a pH equal to or greater than 12, so that the ruthenium is oxidised.

A method and apparatus for transporting syringes containing radioactive material. The apparatus includes a radiopharmaceutical pig having an inner chamber in which a sharps container can be secured. The sharps container has a housing and an attachable cap. The method includes assembling the radiopharmaceutical pig so that the chamber of the radiopharmaceutical pig contains the syringe in the sharps container housing. The radiopharmaceutical pig is disassembled, where upon the syringe is removed, discharged, and then replaced in the sharps container housing. The cap of the sharps container is affixed to the housing of the sharps container, thus enclosing the contaminated syringe therein. The radiopharmaceutical pig is assembled so that its chamber contains the sharps container and the syringe. The radiopharmaceutical pig is transported to a disposal area, where it is disassembled and the sharps container containing the syringe is placed in a particular disposal container.

This invention is provided for improvement of corrosion-resistant property of a crucible and for promotion of safety in a pyrochemical reprocessing method for the spent nuclear fuel. The spent nuclear fuel is dissolved in a molten salt placed in the crucible. In a pyrochemical reprocessing method, the nuclear fuel is deposited, and the crucible (2) is heated by induction heating. Cooling media (5, 6) are supplied to cool down, and a molten salt layer (7) is maintained by keeping balance between the heating and the cooling, and a solidified salt layer (8) is formed on inner wall surface of the crucible.

A radioactive substance decontamination method and apparatus which decontaminates a metal member contaminated by radioactive substance in a short period of time. This apparatus has (1) multiple reducing decontamination tanks having different radiation control values; (2) a carrier for immersing the metal member into the multiple reducing decontamination tanks and a washing tank; (3) a tube for transferring into the second reducing decontamination tank the reducing decontamination agent in the first reducing decontamination tank; (4) a reducing agent decomposer for decomposing a component contained in the reducing decontamination agent of the reducing decontamination tank where the radiation control value is the highest out of the reducing decontamination tanks connected by the tube; and (5) a washing tank for washing the reducing decontamination agent deposited on the decontaminated metal member.

The invention provides a method of separating uranium from at least fission products in irradiated nuclear fuel, said method comprising reacting said irradiated nuclear fuel with a solution of ammonium fluoride in hydrogen fluoride fluorinating said reacted irradiated nuclear fuel to form a volatile uranium fluoride compound and separating said volatile uranium fluoride compound from involatile fission products. The invention thus provides a reprocessing scheme for irradiated nuclear fuel. The method is also capable of reacting, and breaking down Zircaloy cladding and stainless steel assembly components. Thus, whole fuel elements may be dissolved as one thereby simplifying procedures over conventional Purex processes.

In a chemical decontamination method of chemically decontaminating radioactive nuclides from a metallic material, oxalic acid and hydrazine are injected as a reductive decontaminating agent into water that is in contact with the metallic material. Injection of the hydrazine is stopped after a cation resin arranged in a circulation line connected to the metallic material breaks, and at least the oxalic acid and the hydrazine in the reductive decontaminating agent are decomposed using a decomposing catalyst.

A method and apparatus for transporting syringes containing radioactive material. The apparatus includes a radiopharmaceutical pig having an inner chamber in which a sharps container can be secured. The sharps container has a housing and an attachable cap. The method includes assembling the radiopharmaceutical pig so that the chamber of the radiopharmaceutical pig contains the syringe in the sharps container housing. The radiopharmaceutical pig is disassembled, where upon the syringe is removed, discharged, and then replaced in the sharps container housing. The cap of the sharps container is affixed to the housing of the sharps container, thus enclosing the contaminated syringe therein. The radiopharmaceutical pig is assembled so that its chamber contains the sharps container and the syringe. The radiopharmaceutical pig is transported to a disposal area, where it is disassembled and the sharps container containing the syringe is placed in a particular disposal container.

A method and apparatus for transporting syringes containing radioactive material. The apparatus includes a radiopharmaceutical pig having an inner chamber in which a sharps container can be secured. The sharps container has a housing and an attachable cap. The method includes assembling the radiopharmaceutical pig so that the chamber of the radiopharmaceutical pig contains the syringe in the sharps container housing. The radiopharmaceutical pig is disassembled, where upon the syringe is removed, discharged, and then replaced in the sharps container housing. The cap of the sharps container is affixed to the housing of the sharps container, thus enclosing the contaminated syringe therein. The radiopharmaceutical pig is assembled so that its chamber contains the sharps container and the syringe. The radiopharmaceutical pig is transported to a disposal area, where it is disassembled and the sharps container containing the syringe is placed in a particular disposal container.

A method for chemically decontaminating radioactive material. The method includes reducing-dissolving step for setting surface of radioactive material in contact with reducing decontamination liquid including mono-carboxylic acid and di-carboxylic acid as dissolvent; and oxidizing-dissolving step for setting the surface of the radioactive material in contact with oxidizing decontamination liquid including oxidizer. The method may include repeated pairs of steps, each pair including the reducing-dissolving step and the oxidizing-dissolving step. The mono-carboxylic acid may include formic acid, and the di-carboxylic acid includes oxalic acid. The oxidizer may be ozone, permanganic acid or permanganate.

A device for inspecting submersed plant parts is particularly suited for ultrasonic inspection of screws in the core baffle of a nuclear reactor pressure vessel. The device includes a remote-controlled underwater vehicle that is provided at its end face with a carrier that can be pivoted about a pivot axis oriented parallel to the longitudinal central axis of the underwater vehicle, and is provided with a holding device for an inspection head that is arranged on the carrier spaced apart from the pivot axis.

A method for cooling a heat source, a method for preventing chemical interaction between a vessel and a cooling composition therein, and a cooling system. The method for cooling employs a containment vessel with an oxidizable interior wall. The interior wall is oxidized to form an oxide barrier layer thereon, the cooling composition is monitored for excess oxidizing agent, and a reducing agent is provided to eliminate excess oxidation. The method for preventing chemical interaction between a vessel and a cooling composition involves introducing a sufficient quantity of a reactant which is reactive with the vessel in order to produce a barrier layer therein that is non-reactive with the cooling composition. The cooling system includes a containment vessel with oxidizing agent and reducing agent delivery conveyances and a monitor of oxidation and reduction states so that proper maintenance of a vessel wall oxidation layer occurs.

Decontamination of nuclear facilities is necessary to reduce the radiation field during normal operations and decommissioning of complex equipment. In this invention, we discuss gel and foam based diphosphonic acid (HEDPA) chemical solutions that are unique in that these solutions can be applied at room temperature; provide protection to the base metal for continued applications of the equipment; and reduce the final waste form production to one step. The HEDPA gels and foams are formulated with benign chemicals, including various solvents, such as ionic liquids and reducing and complexing agents such as hydroxamic acids, and formaldehyde sulfoxylate. Gel and foam based HEDPA processes allow for decontamination of difficult to reach surfaces that are unmanageable with traditional aqueous process methods. Also, the gel and foam components are optimized to maximize the dissolution rate and assist in the chemical transformation of the gel and foam to a stable waste form.

A variable-voltage variable-frequency power source for an electric motor that drives a re-circulation pump for a boiling water nuclear reactor. The power source has a semiconductor electric power converter and a speed controller for controlling the semiconductor electric power converter. When a part of the semiconductor electric power converter comes into an inoperative state, that part is electrically disconnected, and the variable-voltage variable-frequency power source temporarily stops outputting power, thereby idling the re-circulation pump. Thereafter, the power source re-starts outputting power before the re-circulation pump completely stops. Thus, the re-circulation pump keeps operating, without stopping.

Frames are disclosed for mounting windows within the walls of enclosures for isolating or sealing substances such as radioactive or other hazardous substances from the surrounding environment. In a first embodiment of the present invention, a window assembly includes a two-piece frame that is welded into the wall of an enclosure. In a second embodiment of the present invention, a window assembly includes a three-piece frame that is clamped to the wall of an enclosure. The frame assemblies may also be used to mount structures other than windows to enclosure walls, such as ducts or pipes intended for passing power, gas, vacuum, or other utilities into the interior of an enclosure.

A working apparatus has: a working equipment for doing works on a structure; an operation mechanism adapted to actively move the working equipment relative to the structure; and an adhering/traveling module coupled to the operation mechanism and adapted to adhere to the structure so as to have the weight of the working apparatus borne by the structure and travel/move on the structure for positioning. With this arrangement, the working apparatus can perform accurate positioning operations in a narrow environment and complex scanning operations by means of various pieces of the working equipment such as inspection sensors, and can secure a large working area within a short period of time and reduce the overall working hours.

One form of the invention is directed to an apparatus that comprises step-down circuitry to better match impedance between an input and an output that includes a number of stages each electrically coupled to another and each including a charge storage device. The circuitry further includes a number of switching devices operable in a first electrical connectivity state to connect the charge storage device of each of the stages in series to receive electrical charge from the input and in a second electrical connectivity state opposite the first state to connect the charge storage device of each of the stages in parallel to discharge electricity through the output. This circuitry can be used in connection with a radioisotopic conversion cell.

A vol-oxidizer of spent nuclear fuel, the spent nuclear fuel is injected to a reaction portion, the reaction portion is connected to a driving portion and oxidizes the spent nuclear fuel by rotating and back-rotating the spent nuclear fuel. The oxidized powder of the spent nuclear fuel is gathered in a discharge portion located in a lower portion of the reaction portion. By providing minute powder particles for recycling and a post process of the spent nuclear fuel, even though a size of an apparatus is small, processing a large amount is possible. Time required for oxidation can be reduced, and the powder is readily discharged by gravity since the apparatus is vertically configured.

Disclosed is a separation and receiving apparatus for a spent nuclear fuel rod. The spent nuclear fuel rod is mounted and downwardly transferred by a pin. At this time, a blade peels the hull of the spent nuclear fuel rod. The hull and a pellet positioned therein are separated by a separator. The peeled hull and pellet are each received in respective receiving vessels. Accordingly, since the hull and pellet made of uranium oxide (UO2) may be automatically separated and received in each respective vessel, safety and automation may be guaranteed.

A hydrogen combustion system comprising: an external cylinder 1 constituting the exterior of a double tube construction; an internal cylinder 2 formed by a porous metal plate constituting the interior of said double tube construction; hydrogen combustion catalyst 4 supported with precious metals on spherical ceramic support surface, formed in pellet state, being packed in said internal cylinder 2; an insert pipe 3 formed by porous metal plate inserted in the center of said internal cylinder 2; pre-heating heaters 5 installed between said insert pipe 3 and said internal cylinder 2 to preheat said hydrogen combustion catalyst 4 to ambient atmosphere of over catalytic reaction temperatures; a hydrogen introducing port 8 connecting to said insert pipe 3; an air introducing port 9 provided at the bottom of said external cylinder 1 in the area between said external cylinder 1 and said internal cylinder 2, wherein air for hydrogen combustion is introduced by the drift effect resulting from the differential pressure generated between the packed layer of hydrogen combustion catalyst and the outside, by thermal convection, achieving safe combustion treatment of hydrogen in simple construction, small size and high treatment efficiency.

The present invention relates to a liquid radioactive waste treatment system. The liquid radioactive waste treatment system includes a plurality of evaporation plates and each of the evaporation plates has an uneven surface, in a housing comprised of a glass. A liquid radioactive waste is dispersed via a liquid waste dispersing unit to the evaporation plate, and the liquid radioactive waste is evaporated using solar heat and airflow in the housing.

The flexible glove holder (1) includes a flat structure (13) with three branches (2, 3 and 4) forming an S-shape on which the glove is wound. The holder (1) is then pushed into the opening of the glove box. This rapid action method makes it possible to avoid knotting the gloves when they must be drawn toward the outside for an operation within the box and also allows the implementation of biological protection on the opening of the glove box as well as a protection of the agents against radiation.

Materials and methods of making low-sintering-temperature glass waste forms that sequester radioactive iodine in a strong and durable structure. First, the iodine is captured by an adsorbant, which forms an iodine-loaded material, e.g., AgI, AgI-zeolite, AgI-mordenite, Ag-silica aerogel, ZnI2, CuI, or Bi5O7I. Next, particles of the iodine-loaded material are mixed with powdered frits of low-sintering-temperature glasses (comprising various oxides of Si, B, Bi, Pb, and Zn), and then sintered at a relatively low temperature, ranging from 425° C. to 550° C. The sintering converts the mixed powders into a solid block of a glassy waste form, having low iodine leaching rates. The vitrified glassy waste form can contain as much as 60 wt % AgI. A preferred glass, having a sintering temperature of 500° C. (below the silver iodide sublimation temperature of 500° C.) was identified that contains oxides of boron, bismuth, and zinc, while containing essentially no lead or silicon.

Frames for mounting windows within the walls of enclosures for isolating or sealing substances such as radioactive or other hazardous substances from the surrounding environment. In a first embodiment of the present invention, a window assembly includes a two-piece frame that is welded into the wall of an enclosure. In a second embodiment of the present invention, a window assembly includes a three-piece frame that is clamped to the wall of an enclosure. The frame assemblies may also be used to mount structures other than windows to enclosure walls, such as ducts or pipes intended for passing power, gas, vacuum, or other utilities into the interior of an enclosure.

A system and method for a self-charging battery cell are provided in which beta emissions from a Strontium-90 source are obtained by a sensor device and converted into electric energy. In embodiments, a scintillation device is used to intake emissions from a Strontium-90 source, and consequently emit a light or plurality of light flashes. A sensor device, e.g., a photodiode, is utilized to convert the light or plurality of light flashes into electric voltage, current and/or energy.

Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

A method of repairing a nuclear fuel cell wall and tools useful for performing that repair are described. A repair tool may be used to align a jack near a region of a bent or distorted structural component of nuclear fuel cell and that jack may be used to apply a force to that structural component. Application of such a force may serve to bend the structural component of a nuclear fuel cell in a way to restore the structural component to its position before damage occurred. The repair tool includes a way of mounting that tool to a fuel cell, positioning elements to align the tool near a structural deformation or bent element and a jack that may be use to apply a force to at least one structural component in a fuel cell.

Illustrative embodiments provide a nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system.

A reactor installation tool and method for installing a reactor unit in a reactor tube. A reactor installation tool including a movable assembly and a fixed assembly linked together such that the movable assembly can be adjusted relative to the fixed assembly. The movable assembly including a reactor sleeve attachment means for releasably securing a reactor sleeve loaded with a reactor unit to the tool. The fixed assembly including an expandable clamping unit for releasably securing the tool to a reactor tube. A reactor unit can be installed in the reactor tube by adjusting the movable assembly to extract the reactor unit from the reactor sleeve as the fixed assembly is rigidly secured to the reactor tube. The fixed assembly can be released from the reactor tube and the reactor installation tool can be removed from the reactor tube.

A method for recovery of residual actinide element from chloride molten salts that are formed after electro-refining and/or electro-winning of a spent nuclear fuel and include actinide elements and rare-earth elements is provided. The method comprises conducting electrolysis using a liquid cadmium cathode (LCC) in the chloride molten salt that is formed after electro-refining and/or electro-winning of a spent nuclear fuel and contains rare-earth elements and actinide elements; electro-depositing the actinide elements contained in the chloride molten salt on the LCC in order to reduce a concentration of the actinide elements; and adding a CdCl2 oxidant to the chloride molten salt containing the LCC-metal alloy in order to oxidize the rare-earth elements co-deposited on the LCC, thereby forming the rare-earth chlorides in the chloride molten salt.

Compositions are provided that include nuclear fuel. Methods for treating nuclear fuel are provided which can include exposing the fuel to a carbonate-peroxide solution. Methods can also include exposing the fuel to an ammonium solution. Methods for acquiring molybdenum from a uranium comprising material are provided.

A method for design of a fuel assembly for nuclear reactors, including structural components made from zirconium alloy: the mean uniaxial tensile or compressive stress to which the components are subjected during the assembly life is calculated, the zirconium alloy of which the components are made is selected according to the following criteria: those components subjected to an axial or transverse compressive stress of between −10 et −20 MPa are made from an alloy with a content of Sn between Sn=(=0.025σ−0.25)% and Sn=−0.05σ%: those components subjected to such a stress of between 0 et −10 MPa are made from an alloy the Sn content of which is between Sn=traces and Sn=(0.05σ+1)%: those components subjected to such a stress of between 0 and +10 MPa are made from an alloy the Sn content of which is between Sn=0.05% and Sn=(0.07σ+1)%: and those components subjected to such a stress of between +10 and +20 MPa are made from an alloy the content of SN of which is between 0.05% and 1.70%. A fuel assembly made according to the method.

A method of injecting mortar into a container fastened to a first tank and to a second tank, the first tank communicating with the container via a first orifice and the second tank communicating with the container by a second orifice, the method comprising the following operations: a continuous circulation of a first stream of mortar is made to flow in a circulation loop; during the continuous circulation, a second stream of mortar is drawn off from the circulation loop, the second stream being smaller than the first stream of mortar; the second stream of mortar is injected into the container, ensuring that there is dynamic confinement of the gaseous effluents; and the appearance of mortar in the second tank is monitored and, when this appearance is detected, the removal of mortar from the circulation loop is brought to an end.

Compositions are provided that include nuclear fuel. Methods for treating nuclear fuel are provided which can include exposing the fuel to a carbonate-peroxide solution. Methods can also include exposing the fuel to an ammonium solution. Methods for acquiring molybdenum from a uranium comprising material are provided.

A storage rack arrangement (10) for the storage of nuclear fuel elements in a storage pool includes at least two storage racks (1.1-1.3) which each contain a plurality of vertical channels (9) arranged next to one another for the reception of the fuel elements, with positioning elements (6) being provided at the storage racks at the bottom. The storage racks are connected to one another at the top and the storage rack arrangement (10) additionally includes one or more base plates (2.1-2.3) which are provided with positioning members (8) which fit with the positioning elements (6) of the storage racks (1.1-1.3) and which, together with the positioning elements, position the storage racks with respect to the base plate or base plates (2.1-2.3) to prevent a displacement of the storage racks on the base plate or plates.

An apparatus for treating a radioactive nitrate waste liquid includes: a denitrification tank (12) that accommodates active sludge which adsorbs or takes in a radioactive substance in a nitrate waste liquid (11) containing nitrate and the radioactive substance and in which an anaerobic microorganism that reduces the nitrate to nitrogen gas grows; a reaeration tank (14) that aerates and mixes a denitrification-treated liquid (24) treated in the denitrification tank (12) with the active sludge in which the aerobic microorganism grows; and a sludge dissolution tank (81) that dissolves redundant sludge (26A, 26B) discharged from the denitrification tank (12) and the reaeration tank (14). Acetic peracid (80) is supplied to the sludge dissolution tank (81) to dissolve redundant sludge, a sludge lysate is supplied to the denitrification tank (12) as a carbon source (22), and acetic acid is supplied to the denitrification tank (12).

Illustrative embodiments provide a nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system.

A reactor installation tool and method for installing a reactor unit in a reactor tube. A reactor installation tool including a movable assembly and a fixed assembly linked together such that the movable assembly can be adjusted relative to the fixed assembly. The movable assembly including a reactor sleeve attachment means for releasably securing a reactor sleeve loaded with a reactor unit to the tool. The fixed assembly including an expandable clamping unit for releasably securing the tool to a reactor tube. A reactor unit can be installed in the reactor tube by adjusting the movable assembly to extract the reactor unit from the reactor sleeve as the fixed assembly is rigidly secured to the reactor tube. The fixed assembly can be released from the reactor tube and the reactor installation tool can be removed from the reactor tube.