NF: Support ships for spent nuclear fuel

Publish date: February 6, 2003

There are approximately 5,040 spent nuclear fuel assemblies or about 22 reactor cores containing 8.8 tonnes of fuel materials with a total radioactivity of about 6.6 million Ci stored on the nuclear service ships. Bellona recommends the development of a project aimed at unloading fuel from the nuclear service ships to reduce the treat of radioactive contamination.

At present, the Northern Fleet operates seven nuclear service ships for reactor refuelling services and the short-term storage and transportation of nuclear fuel. These include Malina class (Project 2020; PM-63 and PM-12), Project 326 and 326M (PM-50, PM-78, PM-124, PM-128) vessels.

The four Project 326M vessels were designed at Aisberg design bureau in 1957 and built in Severodvinsk from 1960 to 1966. The Project 326M service ship was used for refuelling first and second generation submarine reactors. Although the Project 326M class nuclear service ships were repaired during their operation, they are all in a bad condition and fall short of safety requirements.

In view of the inadequate radiation safety provisions in the storage sections, the radiation situation for personnel working onboard the vessels is unfavourable. This factor, combined with the unpleasant conditions onboard the ships and long absences away from family have a negative influence on the morale of the crew and in turn affect the level of nuclear safety during operations. The vessels PM-50, PM-78 and PM-128 are all nuclear service ships that are assigned to Olenya Bay. The nuclear service ship PM-124 is based in the water area of Severodvinsk.

The non-propelled Project 326 type nuclear service ship was used for the refuelling of first generation submarine nuclear reactors. The storage compartments of the Project 326 nuclear service ships are capable of holding 560 spent nuclear fuel assemblies or 2.5 reactor cores each. Spent nuclear fuel assemblies are hung up in storage compartments without being contained in any form of cask. The basic technical specifications of these nuclear service ships are given in Table 6.

The Project 2020 nuclear service ships were designed in 1980. The feature that sets these vessels apart from the others is that the shape of the hull has no cam surfaces or flat elements. Due to certain design flaws the ship is difficult to trim, and thus it practically always tilts to one side. All ships of this Project were built in Nikolaev. The PM-63 entered service in the Northern Fleet in October 1984, while the PM-12 began in 1991. The PM-12 is permanently based in the water area of Severodvinsk, whereas PM-63 is assigned to Olenya Bay.

There are four storage sections on the Project 2020 nuclear service ships, with each storage section capable of accommodating 51 transport casks. The total capacity is 204 transport casks of spent nuclear fuel or 1,400 spent nuclear fuel assemblies — almost six reactor cores. The ships are equipped with two cranes with a payload capacity of 16 tons to facilitate the reloading of fuel. The basic technical specifications are given in Table 6.

The nuclear service ship Severka was an upgraded vessel of the River-Sea class, Tissa type. It was built in Hungary in 1957. The ship later entered active service with the Northern Fleet. In 1978, Severka was taken out of operation as a Northern Fleet service ship and was rebuilt to transport containers of spent nuclear fuel to Shipyard No. 35 — Sevmorput. Severka was also used to transport spent nuclear fuel from Andreeva Bay to Murmansk prior to transportation to Mayak for reprocessing.

The ship had two storage sections with a total capacity of 88 TK-11 transport casks and was manned by a civilian crew. In 1993, Severka was taken out of active service; her present location is unknown. The fuel was reportedly removed from Severka and the vessel placed in dry dock at one of the shipyards at the Kola Peninsula.

Name PM-50, PM-78, PM-124 PM-128 PM-63, PM-12
Ship class Nuclear service ship Nuclear service ship
Project number 326 2020
Number of the vessels in the Northern Fleet 4 2
— Empty, ton 3,300 9,700
— Loaded, ton 4,000 13,900
Maximum length, m 92 138
Maximum width, m 13.4 21
Draught displacement, m 4.5 7
Maximum speed, knots Non-propelled 11.5
Maximum travel distance, nm 13,000
Main machinery, Hp Diesel energetic installation 2,700
Crew 59 218
Self sustained operation time 15 45
Refuelling capacity One submarine at a time One submarine or one surface vessel at a time
Payload capacity and number of cranes, ton 2×12 2×16
Table 6. Nuclear support vessels in the Northern Fleet

Bellona considers the storage of spent nuclear fuel onboard the nuclear service ships to be more dangerous than allowing it to remain in the reactors of the retired submarines. The storage sections of the nuclear service ships are not as tight as the walls of the submarine reactors. Therefore, in the event of flooding or capsize, large volumes of water could be radioactively contaminated.

It would therefore seem reasonable to develop and finance a project aimed at unloading fuel from the nuclear service ships to reduce the treat of radioactive contamination.