Defueling of the Papa-Class Submarine

The Papa-class nuclear powered submarine (NPS 501) was laid up in 1986 and decommissioned from the Russian Navy in 1989. It was the only submarine of this class built in the USSR and has a unique reactor design. Special equipment was manufactured for the unloading of spent nuclear fuel (SNF) from the reactors and during the only occasion of SNF unloading in 1980, it was discovered that part of the SNF unloading equipment had design deficiencies and that remedial work was required before this could be used again.

In 2010, the NPS 501 was partially dismantled (this did not include SNF unloading). The fore and aft sections were removed and a three-compartment reactor unit was formed to ensure safe storage afloat. Tenders for the development of the spent fuel assemblies (SFA) removal technology, supervision of its manufacture and deployment and a radiaton survey after recovery of the SFAs is being evaluated.