The method of packaging of spent nuclear fuel
(57) Abstract:The invention can be used for packaging of spent nuclear fuel (SNF) during transportation and/or long-term storage. The method includes loading the SNF with the spacer elements in the container from corrosion-resistant metal, heating the container, fill the spent molten metal holding solidification of the melt and seal the container. Fill the spent fuel is carried out by melting of fusible metal or alloy directly into a container and dip the SNF in the melt. The sealing of the container is performed using the cap. The technical result of the invention is to reduce the likelihood of leaks in the fuel cladding and the reduction of the release of radioactive substances from the spent fuel during packaging and storage. 3 C.p. f-crystals, 4 Il. The invention relates to nuclear technology, and can be used for packaging of spent nuclear fuel (SNF) during transportation and/or long-term storage.There is a method of storing cassettes containing spent fuel in cooling pools under a layer of water . The disadvantage of this method should recognize the high probability of release of radionuclides sleet such spent fuel storage limited.The closest analogue is possible to recognize packing SNF (cassettes or bundles of fuel rods), characterized by the placement of spent fuel using the spacer elements in the thin-walled container made of corrosion-resistant metal, welding to the container top cover with holes for pouring molten metal and ventilation, heat the container with spent fuel, fill the container through the holes of the molten low-melting metal or alloy based on it, solidification of the melt in the container, welding holes in the top cover and the operations of the current and final control of tightness of the container of spent nuclear fuel . The disadvantage of this method should recognize the high probability of leaks in the fuel cladding during heating in the process of pouring the melt or in preparation for filling and release significant amounts of radioactive gases into the gas purification system or in the environment, as well as the multistage and the complexity of the process of filling containers.The technical result is obtained as a result of implementation of the invention is to reduce the likelihood of leaks in the fuel cladding and the reduction of the release of radioactive substances from spent fuel for packaging of metal or alloy, spend the melting of fusible metal or alloy, using the spacer elements are immersed preheated SNF in the melt, utverjdayut melt sealing of the container is carried out by welding the top cover. Preferably the melt fusible metal or alloy and heating the spent fuel is carried out in a single sealed volume, bounded from below by the container top is connected with the container boot vacuum chamber to accommodate the spent fuel. Usually as a fusible metal or alloy used lead or alloy based on it, and choose the volume of the melt is equal to or greater volume of gas cavities in the container in the area of the spent fuel.In Fig. 1 to 4 show various stages in the process.In a container, comprising (Fig. 1) of the cylindrical shell 1 and welded to the bottom part 2, download the fusible metal 3 (Fig. 2). The container is placed in a heating furnace 4. The upper end of the shell 1 is sealed (with sealing 11) connect with boot vacuum chamber 5 (Fig. 3) in which with the use of fastening elements 6 SNF 7. The camera 5 is connected to the gas purification system 8. Spend the melt fusible metal or splat using fastening elements in the molten metal 3 (Fig. 3). Spend pouring molten gas cavities and gaps, cooled and crystallized melt to obtain monolith 10. Then disconnect from the container chamber 5 and seal the container by welding thereto of a cover 9 (Fig. 4).The use of the proposed method will improve the reliability of long-term storage of SNF through the creation of additional high-performance corrosion-resistant barrier between the SNF and the environment, to ensure the retention of radioactive products inside the container, loosen the radiation from the spent fuel, to increase the efficiency of cooling of spent fuel, as well as to expand the scope of application of the method not only for storage but also for transportation. 1. The method of packaging of spent nuclear fuel (SNF), including its load by using the spacer elements in the container from corrosion-resistant metal, welded to the container top cover, heating the container, fill SNF molten low-melting metal or alloy, conducting solidification of the melt and seal the container, characterized in that the pouring of the spent fuel is carried out by melting of fusible metal or alloy directly in a container and dip the SNF in the melt, and gerlene fusible metal or alloy in the container and additional heating is carried out in a single sealed volume, bounded from below by the container, and the top is connected with the container boot vacuum chamber to accommodate the spent fuel.3. The method according to p. 1, characterized in that as a fusible metal or alloy used lead or alloy based on it.4. The method according to p. 1, characterized in that the amount of melt is chosen equal to or greater than the amount of gas cavities in the container in the area of the spent fuel.
FIELD: safety facilities for handling radioactive materials.
SUBSTANCE: proposed internal container designed for long-time storage and transport of high-radioactivity materials such as plutonium dioxide has container body closed with sealed cover and specified-volume charging box placed in this body and provided with its respective cover. Container body has cylindrical passage for charging box that mounts additional internal cover provided with gas filtering device and hermetically installed relative to its surface for axial displacement. External cover of container body is provided with shut-off valve accommodating gas filtering device installed therein between inner space of container and valve seat. Such mechanical design of container enables reducing irreparable loss of plutonium during its long-time storage and transport.
EFFECT: enhanced safety and reliability , enlarged functional capabilities of container.
7 cl, 2 dwg
FIELD: handling radioactive wastes.
SUBSTANCE: proposed method for nuclear fuel storage in container includes introduction of nuclear fuel in fuel collector, as well as preparation of formwork to receive concrete body and installation of fuel collector into formwork. Formwork is immersed in tank and concrete is placed in immersed formwork to form concrete housing. Formwork with concrete housing formed therein is extracted from tank. System for manufacturing nuclear fuel storage container and for holding fuel in fuel collector installed in concrete housing that forms part of storage container has water tank. In addition it has tools for assembling formwork for storage container concrete housing and facilities for conveying formwork and fuel collector to water tank. It also has facilities for introducing nuclear fuel in fuel collector, facilities for concrete placement in formwork, and those for removing formwork from water tank. Nuclear fuel storage method includes piling of containers so that their central channels are aligned and held open for intercommunication. Fluid cooling agent is supplied to bottom end of central channel in lowermost storage container and discharged from top end of central channel in uppermost storage container.
EFFECT: enhanced reliability of radioactive waste isolation.
25 cl, 7 dwg
FIELD: storage of hazardous materials.
SUBSTANCE: proposed device for keeping in storage hazardous materials such as spent radioactive nuclear fuel has cylindrical concrete housing accommodating three-dimensional pre-stressed hardware and axially elongated hazardous-material storage area. Pre-stressed hardware includes hardware fittings spirally passed about storage area and disposed in concrete housing close to outer surface.
EFFECT: enhanced reliability of hazardous material storage.
7 cl, 8 dwg
FIELD: shipment and storage of highly active wastes.
SUBSTANCE: proposed container for transport and dry storage of spent nuclear fuel has hermetically sealed storage tank and can holding spent nuclear fuel. In addition, it has external steel-reinforced concrete casing with outer and inner metal shells and bottom, cooling ducts, and fixing dampers. Hermetically sealed tank is provided with transport ring that holds shell in position relative to longitudinal axis of casing and with three detachable lids. It is also provided with dampers disposed over entire perimeter of inner cylindrical shell that function to lock cylindrical shell on lid and outer steel-reinforced concrete casing and to transfer heat therefrom. Cooling system is designed so that cooling air flows through cylindrical gap between outer surface of tank and inner surface of external steel-reinforced concrete casing over cooling ducts.
EFFECT: enhanced operating reliability of container.
5 cl, 4 dwg
FIELD: handling spent nuclear fuel.
SUBSTANCE: proposed module designed for storage of spent nuclear fuel has tight case with inner space to receive spent nuclear fuel. Module is provided with ring made of solid ferromagnetic material possessing magnetocaloric properties. Ring is provided with drive and is free to rotate about its axis. It is disposed so that part of this ring is inside module in immediate proximity of tight tank holding spent nuclear fuel. Other part of ring is placed in constant magnetic field outside of module and can be cooled.
EFFECT: enhanced safety of spent nuclear fuel dry storage.
1 cl, 2 dwg
FIELD: nuclear engineering.
SUBSTANCE: proposed device for storage and/or transport of spent nuclear fuel has housing and cover forming inner space for holding spent nuclear fuel. Inner space is divided by means of partitions into compartments, each compartment being meant to receive spent fuel assembly. Each compartment accommodates two tanks holding metal hydride or intermetallic compound. These tanks are provided with channels pressurized with respect to inner space of device which are used to discharge hydrogen produced due to heat released by fuel assembly. Hydrogen outlet channels are designed for charging metal hydride through them and are provided with closing valves.
EFFECT: enhanced reliability of spent nuclear fuel storage and its safety in transit.
1 cl, 3 dwg
FIELD: transport and storage of spent nuclear fuel.
SUBSTANCE: proposed method includes placement of fuel assemblies in transport package incorporating container and split damping casing designed so as to minimize lift of container when inserting it in split damping casing. Transport package is conveyed to storage place where container is freed of casing, whereupon spent fuel assemblies are kept in storage place. In the process spent fuel assemblies are first placed in container and then the latter is inserted in vertical position into split damping casing made in the form of removable drum with butt-end covering and base that functions as end lid of this drum. Charged container is installed on base, covered on top with removable drum, and the latter is fastened to base. Then split damping casing is secured to container, whereupon transport package is conveyed in transport position to storage place.
EFFECT: enhanced reliability of storage and transportation.
6 cl, 5 dwg
FIELD: nuclear engineering.
SUBSTANCE: proposed method includes loading spent fuel assemblies in metal-concrete container, conveying the latter to intermediate storage site, and holding it on storage sire. Shipping unit for conveying spent fuel assemblies to intermediate storage site has flat-car for carrying vertically mounted container holding spent fuel assemblies. Container is provided with external removable circular supporting member engageable with mating supporting surface of flat-car frame and means for locking container relative to mentioned frame. Shipping unit is provided with jacks for lifting the frame to load spent fuel assemblies in container. Side surface of container body has rigging members in the form of seats on its top and bottom ends. Bottom end of container is installed inside mentioned circular supporting member. Container locking means include radially disposed submersible adjustable stops.
EFFECT: enhanced reliability and safety of proposed method and device.
4 cl, 8 dwg
FIELD: storage and transportation of used nuclear fuel.
SUBSTANCE: metal-concrete container for transportation and/or storage of used assemblies of fuel elements of nuclear reactors has case with bottom, internal protection air-tight cap, edge damping members. Casing with central cell is inserted inside cavity of case. Peripheral cells are disposed around central cell for mounting housings with used assemblies of fuel elements. Peripheral cells are made in form of tubular members that are mounted to have spaces in relation to internal protection air-tight case and bottom of case. Casing has longitudinal rod members disposed around circle in relation to central cell of casing. Container has first and second sheet members which are mounted along height of case and are connected for disconnection by means of longitudinal rods. Edge damping members are made in form spring-shaped members and they are mounted onto internal protection air-tight cap each in opposite to corresponding cell of casing for interaction with housing under normal conditions of exploitation of metal-concrete container.
EFFECT: higher safety of handling of loaded container.
6 cl, 7 dwg
FIELD: storage and transportation of spent nuclear fuel.
SUBSTANCE: proposed metal-concrete container for transportation and/or storage of nuclear-reactor spent fuel assemblies has housing with bottom, internal pressurizing safety cover, hood inserted into housing and provided with cells to receive boxes with spent fuel assemblies. Container also has damping members engageable with cover on inner surface end, with housing bottom, and with housing internal wall. Hood is installed within housing in a space relation to housing internal wall. Side damping members are installed between the latter and hood. Each damping member is made in the form of longitudinal rod passed through holes in respective first and second sheet members installed throughout container height on internal wall of housing and on hood and disposed in parallel with housing bottom.
EFFECT: enhanced reliability of spent nuclear fuel storage.
6 cl, 5 dwg