METHOD FOR REMOVING CAISSONS FROM STORAGE WAREHOUSE OF NUCLEAR PROCESS SERVICE VESSELS WITH DEFECTIVE SFA OFF-NORMALLY ARRANGED IN THEM Russian patent published in 2010 - IPC G21F9/28 

FIELD: power industry.

SUBSTANCE: invention can be used during removal of caissons with defective spent fuel assemblies (SFA) arranged in them, kept in storage warehouses of nuclear process service vessels (ATQ). In protective plug of loading caisson hole in rotary plate installed on storage warehouse tank, there made is the hole through which, by turning the plate and aligning this hole in turns with all the caissons, modified epoxyacrylic composition (MEAC) with the following component ratio, wt %, is filled to cavity of each caisson up to upper level of fuel part which is located in SFA caisson at the highest level: epoxy resin 54÷57, acrylic acid 36÷38, plasticising agent dibutyl phthalate or tributyl phosphate 5÷10 and exposed for the composition curing period. Then in turning plate, coaxially with the above loading hole there bored is the hole the diameter of which is more than outer diameter of caisson and all the suspended SPA parts projecting beyond envelope diameter of the caisson are inward bent through the obtained hole. After that process cover plate is installed above each caisson by being pressed with stop screw to tube sheet of the tank; at that, cover plate includes fixings, loading cap and branch pipe. Then all caissons are filled through the appropriate branch pipe with preserving concrete till their inner volumes and cover plates are fully filled, and process exposure is performed for 28 days. After concrete is hardened, there removed in turns are caissons from storage warehouse; for that purpose, slings are attached to the caisson and the appropriate hole is made under it in the housing design of storage warehouse of vessel, caisson is cut from tube sheet and tank bottom; after that it is reloaded by means of reloading packing made in the form of turned-over glass having at the bottom the hole for passage of tie-down rope to transport radiation protective container which is transported for long-term storage. In special case of the proposed method the caissons are removed after cases with SFA have been removed from storage warehouse.

EFFECT: reliable and economically cheap removal procedure of caissons with defective SFA from storage warehouses of utilised ATQ vessels, thus providing nuclear safety and sufficient radiation safety, and their further long-term storage.

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