RU2153713C1 - Device for separating end parts from spent fuel assemblies - Google Patents

Abstract

FIELD: spent nuclear fuel recovery in radiochemical industry. SUBSTANCE: end part is separated from active section of spent fuel assembly by cutting it with knife performing translational and rotary motion relative to auxiliary cutting blades of movable hold-down device and support which function to hold tight the fuel assembly at cutting point, knife blades being shaped to follow shape of fuel assemblies being treated. Such process ensures reliable separation and cutting without forming finely dispersed fractions of fuel assembly can material and liquid radioactive wastes. EFFECT: reduced power requirement, improved radiation safety and capacity. 3 dwg

Description

 The invention relates to nuclear engineering and can be used in radiochemical production for separating ring parts from the active part of spent fuel assemblies (OTS) of nuclear reactors during the regeneration of spent nuclear fuel (SNF).

 An analogue of the present invention is a device for processing irradiated nuclear fuel. The device is designed to remove the front covers and end grids of the fuel cartridges and cut the cartridges into pieces of a certain length for their subsequent processing. The processing device consists of a hermetically sealed container, a device for moving assemblies, horizontal and vertical clamps, a saw (GB 1314803 A, G 21 C 19/34, 04/26/73).

 The disadvantage of this device is the design complexity, large size and the inability to separate the front covers and end gratings of the cassette without its separation into pieces of a certain length.

 A prototype of the invention is a device for cutting fuel assemblies, consisting of a protective plug, a mounting plate, a movable console, a cutting body in the form of a rotating disk, clamps, disk rotation drives and console supply, a power source, a current supply system (DE 2639059 A1, G 21 C 19 / 36, 03.24.77).

 The disadvantage of this device is that due to the use of high electric current densities at the contact points of the clamps and the zirconium jacket pipe, there is a real risk of an electric arc and burning of the structural shells of the SFA, which entails the unauthorized opening of the active zone. The second disadvantage is the formation of finely dispersed fractions of the destroyed SFA shell.

 An object of the invention is to provide a device for reliable separation of the end parts from the active part of the SFA, increasing the productivity of the process, reducing energy consumption, increasing the radiation safety of the process, reducing the cost of production.

 The problem is solved using a device consisting of a protective plug, a mounting plate, a fixed console, a block of knives having a fixed support, a movable clamp and a movable knife equipped with cutting planes in shape and size corresponding to the external shape of the shell of a SFA of hexagonal or square section, with this movable knife is mounted on the axis with the possibility of rotational movement together with a detachable part around the axis of the stationary cutting edges.

 A general view of the proposed device is shown in FIG. 1, where 1 - SFA; 2 - motionless support; 3 - movable clip; 4 - the upper half of the knife; 5 - the lower half of the knife (the dotted line shows the position after completion of the cut); 6 - fixed cutting plane of the clamp and support; 7 - cutting plane of the knife (the dotted line shows the position after completion of the cut); 8 - the axis of rotation of the knife relative to the stationary cutting planes of the support and clamp; 9 - console; 10 hydraulic cylinder; 11 - a protective stopper; 12 - mounting plate; 13 - axis of joint rotation of the clamp and knife.

 In FIG. 2 shows a section of a block of knives along AB, where 1 is a SFA; 2 - motionless support; 3 - movable clip; 4 - the upper half of the knife; 5 - the lower half of the knife; 6 - stationary cutting cutting plane; 7 - movable cutting plane of the knife; 13 - axis of joint rotation of the clamp and knife.

 A device for separating the end parts from the active part of the SFA operates as follows.

 The processed fuel assembly 1 is placed on the bed of the knife block formed by the support 2 and the lower half of the knife 5. Using the hydraulic cylinder 10 of the clamp 3 and the upper half of the knife 4 rotate around the axis 13 and the SFA is crimped along all faces of the assembly. The active part of the SFA is clamped between the support 2 and the clamp 3, and the end piece is clamped between the knife halves 4 and 5. Further movement is made only by both halves of the knife around axis 8 together with the clamped end piece. The cutting process simultaneously involves all the cutting planes of the clamp, support and knife. After separation of the end part, the upper half of the knife and the clamp return to their original position, the SFA and the end part are removed.

 A general view of the device for separating the end parts of the SFA of circular cross section with the possibility of placing one or more SFA is shown in FIG. 3, where 1 - SFA (2 pcs.); 2 - motionless support; 3 - movable clip; 4 - the upper half of the knife (the dotted line shows the position after completion of the cut); 5 - the lower half of the knife (the dotted line shows the position after completion of the cut); 6 - fixed cutting plane of the clamp and support; 7 - cutting plane of the knife (the dotted line shows the position after completion of the cut); 8 - the axis of rotation of the knife relative to the stationary cutting planes of the support and clamp; 9 - console; 10 - a hydraulic cylinder; 11 - a protective stopper; 12 - mounting plate; 13 - axis of joint rotation of the clamp and knife.

 In FIG. 4 shows a section of a knife block according to AB, where 1 is a SFA (2 pcs.); 2 - motionless support; 3 - movable clip; 4 - the upper half of the knife; 5 - the lower half of the knife; 6 - fixed cutting plane of the knife; 7 - movable cutting plane of the knife; 13 - axis of joint rotation of the clamp and knife.

 The technical result of the invention is to provide a reliable safe separation method, eliminating the formation of fine fractions of the material of the destroyed SFA shell and liquid radioactive waste, reducing energy costs by reducing energy consumption, increasing the radiation safety of the process by eliminating the opening of the SFA core, and increasing the productivity of the process by reducing time of separation of the end part, simplifying the design by providing two movements (f ksatsiya SFA and cutting the end piece) with a single drive.

 The conducted experimental study on the SFA simulators gave positive results.

Claims (1)

 A device for separating the end parts of spent fuel assemblies (SFA), including a protective plug, a mounting plate, a movable clamp, a cutting body, a clamp drive and a knife, characterized in that the cutting body is made in the form of a movable clamp and knife and a fixed support provided with cutting planes , in shape and size, corresponding to the external shape of the SFA sheath, while the movable knife is mounted on the axis with the possibility of rotational movement together with a detachable end part around the axis of the stationary cutting planes d.

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