Protective container for transportation of spent fuel assemblies of nuclear reactors

 

(57) Abstract:

Protective container for transportation of spent fuel assemblies of a nuclear reactor includes a housing closed at the top by a sealing cap, and inserted into the body cavity of the removable part, through the holes in the diaphragms which distantsionno posted pouches with SFA. Covers of various sizes or set their bottom ends to the bottom of the container, or suspended on the supporting clamps in the holes of the boards removable parts for the upper shoulders of the covers. The backlash from the middle of the field of tolerance upper ends of the sleeves to the middle of the field tolerances for pitch-shifted cavity of the container, the height of the cover and the diaphragm cover and removable parts, and the middle of the field tolerances planes of symmetry of the diaphragm covers the start and end positions of the covers in the container is shifted by half of the gap relative to the means of the fields tolerances planes of symmetry of the diaphragm removable parts. The sum of the heights of the cylindrical surfaces of the diaphragms of the removable parts and the case has a value of 2.2 - 3.0 magnitude of the sum of the tolerances on pitch-shifted cavity of the container, the height of the cover and the diaphragm cover and the removable parts. The technical result - the security in case of emergency PA is appointed for safe transportation from stores after the necessary exposure to the plants regeneration fuel spent fuel assemblies (SFA) of nuclear reactors in a vertical position in accordance with the requirements of nuclear and radiation safety.

Known protective container ("Nuclear energy", vol. 39, vol. I, July 1975, page 46, Fig. 2 and Fig. 3), which is a group of devices, providing distantsionnnoe accommodation SFA in the cavity of the container and eliminating the possibility of rearrangement of the SFAS in the reactive system for the occurrence of spontaneous nuclear chain reaction, including after an abnormal drop of the container during its transportation by any mode of transport.

Known protective containers (see GOST 21470-76 hell. 1-3, PL. 1 and GOST 21471-76 hell. 1-7, PL. 1-2), comprising a housing inserted into the body cavity of the removable part, in the holes of the top Board and transverse diaphragms which distantsionno posted by overlapping apertures (or lattices) sealed tube covers containing the SFA.

Closest to the claimed device, the combination of features is chosen as a prototype protective container for transport of spent assemblies of the reactor ("Containers for transportation of spent fuel elements of nuclear power plants", Proceedings of CKTI, issue 142, Leningrad, 1977, page 13, Fig. 2) closed at the top by a sealing cover and having a compression spring / damper device over verhnjaja along its axis.

The disadvantages of these known protective containers inserted in them removable parts and covers is uniformity placed in their cavity covers with SFA and adenomectomy bearings covers a combination of different sizes of covers and combinations of the alternative sites for their support in the cavity of the container. This reduces the possibility of co-location in the cavity of the container covers with SFAS various sizes.

Another disadvantage of the known protective containers is securing the upper ends of the covers special pressure snubber mechanical devices in the gap under the lid, which does not prevent from jamming covers the openings of the diaphragms removable parts due to breakage of the pressure device in case of emergency drop the container on the lid and strain the removable parts due to the failure of the pressure devices, and thermal deformations in case of fire.

To prevent deformation of the removable parts and eliminate jamming covers accidental fall of the protective container on the lid covers should have the opportunity of free movement of its diaphragm on the diaphragm removable parts on the size of the gap to lock the upper ends of the covers in orzhov covers given the emphasis in the bottom of the cover should be carried out without mechanical adjusting devices.

The objective of the invention is to increase the number of sizes of covers with SFAS various lengths and diameters, placed together in the cavity of the container; nuclear safety by preventing Assembly of the diaphragms covers with diaphragms removable parts emergency drop container and eliminate the possibility of rearrangement of the SFAS in the reactive system, and ensuring that the same gap under the cover over the ends of the covers and software amortization covers given the emphasis in the bottom of the cover.

This is achieved by jointly in the cavity of the container covers of various sizes or set their bottom ends to the bottom of the container, or suspended on the supporting clamps in the holes of the boards removable part at the top of the container shell for the upper shoulders of the covers. Thus the value of the gap from the middle of the field of tolerance upper ends of the sleeves to the middle of the field tolerance of the bottom of the cover has the value from the half-sum to the sum of the values of the tolerances on the detuning of the cavity of the container, the height of the cover and the diaphragm cover and the removable parts; and the middle of the field tolerances planes of symmetry of the diaphragm covers the container at the start and end positions of the covers in the container is shifted by half of the gap relative to the sulfur is fragm removable parts and case counts, 2,2-3,0 value of the sum of the tolerances on the detuning of the cavity of the container, the height of the cover and the diaphragm cover and the removable parts.

To achieve the same gap under the lid over all covers and software amortization covers accidental falling of the container on the lid at the upper ends of the covers until it stops at the ends of the worn upside down with the required thickness of the bottom of the removable hollow cylindrical buffer having at the bottom of the cavities fixed rubber gaskets.

The same gap under the lid over all cases is achieved by the fact that the holes of the boards removable parts for suspended covers installed replaceable sleeve to the desired height. To ensure the depreciation of the covers accidental falling of the container to the cover on the bottom cover attached rubber pad.

The essence of the invention is illustrated by drawings, where Fig. 1 is a top view of the protective container, a vertical section; Fig. 2 - node 1 in Fig. 1, worn upside down on the top end of the hollow cylindrical case, a buffer mounted on the bottom of the cavity of the rubber pad in the transport position of Fig. 3 - scheme of combining diaphragm covers and removable parts and communications heights diaphragm with a gap the EP includes a housing 1, the cover 2, the removable part 3, consisting of the top Board 4 attached to the bottom Board 4 uprights 5, partitioned transversely attached to the posts 5 spacer orifice 6. This removable part 3 Board 4 rests on top of the housing 1, and the rack 5 can't touch the bottom of the housing 1, i.e., the removable part 3 hanging. Through the holes of the Board 4 and the openings of the diaphragms 6 removable parts 3 installed their bottom ends to the bottom of the housing 1 sealed tubular cover 7 with a combination of spacer apertures 9 covers 7 with the spacer diaphragms 6 removable parts 3 (scheme combining diaphragm covers and removable parts shown in Fig. 3).

Together with installed on the bottom of the housing 1 covers 7 in the holes of the top Board 4 on the support shoulders hanging by their upper shoulders sealed tube covers 8 different sizes with a combination of the spacer diaphragms 6 and 9. Between the upper ends of the covers 7 and 8 and the bottom of the cover 2 there is a gap. In initial and final positions of the covers 7, 8 in the container mid-field tolerances planes of symmetry of the diaphragm 9 of the covers 7 and 8 are shifted by half of the gap relative to the means of the fields tolerances planes of symmetry of the diaphragm 6 removable parts 3 (see Fig. 3).

Dov 7 and 8 in case of emergency drop the container on the lid 2 on the upper ends of the covers 7, 8 worn upside down until it stops at the ends of the sleeves 7, 8 rubber ethylene-propylene gaskets 13 removable hollow cylindrical buffer 12 of the required thickness H (see Fig. 2).

In another embodiment (see Fig. 1) to maintain a uniform gap under the cover 2 over the faces of the covers 7, 8 in the holes of the Board 4 for suspending the covers 8 are installed replaceable sleeve 10 to the desired height. To the bottom of the cover 2 for cushion covers 7, 8 accidental falling of the container cover 2 is attached rubber ethylene-propylene gasket 11.

Permanent alignment of the apertures 6 removable parts 3 with the apertures 9 of the covers 7, 8 in the initial position and after the move covers the gap until it stops at the bottom of the cover to the end position (see Fig. 3) is expressed by the following signs and ratios:

3 - the size of the gap from the upper ends of the sleeves to the bottom of the cover,

to - the tolerance on the height of the cavity of the container,

h - the tolerance on the height of the case,

QH - tolerance on displacement of the diaphragm cover the height,

DV - tolerance on displacement of the diaphragm removable parts on its height in the cavity of the container.

The tolerances of other components to the container height are the values in which Rahm removable parts,

H - the height of the cylindrical surface of the diaphragm covers,

CAND- the value of the initial alignments of the cylindrical surfaces of the diaphragms removable parts and covers,

CBthe ultimate alignment of the cylindrical surfaces of the diaphragms removable parts and covers,

A - values of the distances between the horizontal planes of symmetry of the diaphragm covers and horizontal planes of symmetry of the diaphragm removable parts in their fields of tolerances in the initial (lower) position covers the container,

B - values of the distances between the horizontal planes of symmetry of the diaphragm covers and horizontal planes of symmetry of the diaphragm removable parts in their fields of tolerances in the final (top) position of the covers in the container.

In the initial (lower) and end (top) the provisions of the covers (see Fig. 3) in the container the horizontal plane of symmetry of the diaphragm covers and diaphragms removable parts are located relative to each other at distances equal to the sum of half of the gap and one-half of the algebraic field values of the tolerances on the height of the cavity of the container, the height of the case and the displacement of the diaphragms removable parts and case. From videprinter follows:

< / BR>
From the schema alignments in Fig. 3 follows:

< / BR>
or

B + H > 3 + K + h + QH + DK = i (8)

Let us denote the sum of the tolerances to + h + QH + DK = i (9)

then B + H > 3 + i (10)

If the sum of the fields tolerances i is determined by the capabilities of the technology, the size of the gap must be rationally selected for constructive reasons. On the one hand, the gap should be more than any of the largest of these tolerances. Since tolerances and h have approximately equal size, approximately the same order of the heights of the cavity of the container and cover and absolute values exceed the tolerance values DF and DK , the condition - gap length more than the largest of tolerances meet the inequality:

< / BR>
On the other hand, the gap should not be excessive because of the increased elevation of the diaphragm and the flow of materials for their manufacture. In the present invention, the gap is set to:

< / BR>
i.e., from the half-sum to the sum of the values of the tolerances on the detuning of the cavity of the container, the height of the cover and the diaphragm cover and the removable parts.

As can be seen from (10), the sum of the heights of the apertures of the cover and the removable parts should be greater than the amount specified gap and all Polk > 2i (14)

A large value of the sum of the heights of the apertures removable parts and irrational case for constructive and technological reasons (increase in weight, increase in consumption of materials, complexity of manufacturing, etc.,),

To ensure permanent alignment of the apertures with each other in the process of moving blankets on the distance from the initial position to the stop in the bottom of the cover accidental falling of the container in the proposed container is the sum of the heights of the diaphragms of the removable parts and the case has been taken equal to (2,2-3,0) the magnitude of the sum of the tolerances on the detuning of the cavity of the container, the height of the cover and the diaphragm cover and the removable parts, i.e.

B + H = (2,2 - 3,0)i (15)

Container is running, as follows.

In case of an accident in the fall of the container cover 2 located therein covers 7, 8 of different sizes as established by their lower ends on the bottom of the container and suspended on the supporting clamps in the holes of the Board 4 and the removable parts 3 to align the gap under the lid 2 or buffers 12 or removable sleeves 10, move freely, their apertures 9 on the diaphragms 6 removable parts 3 on the magnitude of the gap under the cover 2 until it stops at the bottom of the cover 2, which is fixed to entsoe the combination of the cylindrical surfaces of the diaphragms 6, 9 to each other is provided in the initial and final position with the stop on the top ends of the sleeves 7, 8 and buffers 12 in the bottom of the cover 2.

This combination is achieved with a proper choice of the initial and final position and height of the diaphragms 6, 9 in the cavity of the container, and the gap under the lid 2. In the end position, the covers 7, 8 rest against the bottom of the cover 2 buffer 12 with a rubber gasket 13 or the end cover at the bottom of the cover 2, which is fixed to the rubber gasket 11, which provides cushioning covers 7, 8 when hit in the bottom of the cover 2 when the emergency drop container.

This ensures nuclear safety by preventing Assembly of the diaphragms 6, 9 to each other in case of emergency drop the container on the lid 2 as in normal conditions and in case of fire. In fire conditions due to the free movement of the covers 7, 8 on the diaphragms 6, 9 excluded them jamming in the removable parts 3 and the cavity of the container due to thermal stresses and deformations of the component parts of the container 1, 2, 3, 7, 8. Also provided free viem covers 7, 8 after the vertical mounting of the container to its original position and remove the cover 2.

The proposed protective container provides its nadanova placement of SFAS in the cavity of the container not only in the transverse direction, but also along its axis with increasing number of co-located therein sizes of covers with SFAS various lengths and diameters.

1. Protective container for transportation of spent fuel assemblies of nuclear reactors, comprising a housing inserted into the body cavity of the removable part, through the holes in the diaphragms which distantsionno posted pouches with SFA, and closed at the top by a sealing cap, wherein the covers of various sizes or set their bottom ends to the bottom of the container, or suspended on the supporting clamps in the holes of the boards removable parts for the upper shoulders of the covers, with the backlash from the middle of the field of tolerance upper ends of the sleeves to the middle of the field tolerance of the bottom of the cover has the value from the half-sum to the sum of the values of the tolerances on pitch-shifted cavity of the container, the height of the cover and the diaphragm cover and removable parts, and the middle of the field tolerances planes of symmetry of the diaphragm covers the start and end positions of the covers in the container is shifted by half of the gap relative to the means of the fields tolerances planes of symmetry of the diaphragm removable parts, the sum of the heights of the cylindrical surfaces of the diaphragms of the removable parts and the case has a value of 2.2 years.

2. The container under item 1, characterized in that the upper ends of the covers until it stops at the ends of the worn upside down with the required thickness of the bottom of the removable hollow cylindrical buffer having at the bottom of the cavities fixed rubber gaskets.

3. The container under item 1, characterized in that the holes of the boards removable parts for suspended covers installed replaceable sleeve to the desired height.

4. The container under item 1, characterized in that at the bottom of the container is fixed a rubber gasket.

 

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