METHOD TO DISMANTLE CAISSONS WITH DEFECT IRRADIATED FUEL ASSEMBLIES FROM STORAGE OF NUCLEAR-TECHNOLOGICAL SUPPORT VESSELS Russian patent published in 2013 - IPC G21F9/34 

FIELD: power engineering.

SUBSTANCE: invention relates to methods for radioactive wastes handling and may be used to dismantle caissons with installed defect irradiated fuel assemblies (IFA), which are in storages of nuclear-technological support (NTS) vessels. In a cavity of each caisson they add in sequence large-sized polyethylene, a mixture of crushed stone fractions, steel shots, and then Wood's alloy granules to the level of IFA brackets, afterwards the caisson is cut from the tube sheet of the storage tank, heated to melting with subsequent cooling and hardening of the Wood's alloy, afterwards a lifting cover is welded to the upper end of the caisson, and it is loaded with axial stretching load, then circular cutting of the caisson wall is carried out below location of fuel parts of the IFA with partial cutting of of the wall leaving 0.3-0.4 mm, then the axial stretching load is removed from the lifting cover, the caisson is torn off by jacks and transferred with the help of a transfer container into a transport radiation-safe container for storage and processing.

EFFECT: invention makes it possible to minimise radioactivity emissions into environment.

4 cl, 9 dwg