In the aftermath of the tragic sinking of the Russian nuclear submarine K-159, the question remains about whether it should be raised or left on the sea floor. The Russian Navy has, in fact, already promised that the submarine will be lifted. But what are the environmental consequences of leaving the submarine at the sea bottom, and what are the risks involved in a lifting operation?
Bellona Position Paper
As long as the K-159, with its two nuclear reactors on board, sits at the sea bottom, it will represent an environmental hazard. Sooner or later radioactivity in the reactor cores will start to leak out into the seawater, and contamination will result. Based on experience garnered from previous sunken nuclear submarines, like the Komsomolets in 1987, the contamination will first happen locally.
In a longer-term scenario, the contamination would migrate further into the Barents Sea. This migration would particularly concern hot particles that are created as a result of any electrochemical process that may take place in the reactor. Such hot particles are small metal particles, heavily contaminated with alpha-emitters. Plutonium is one example.
The fact that the K-159s reactors had been shut down since 1989 means that there is very little heat production left in the reactor cores. The lack of heating means that there is no longer an elevated pressure inside the reactor tank that would help keep corrosive seawater out. Compounding radiation hazards is the water pressure at the depth of 238 metres, at which the K-159 lies, that will further increase the risk for seawater crushing into the reactor compartments and getting into the reactor.
The psychological factor of having a nuclear submarine resting at the bottom of the fish-rich Barents Sea must also be taken into account. For the fish exporting industry in Norway and Russia, rumours about radioactively contaminated fish could have a dramatic market impact on the sale of fish from the Barents Sea. The Bellona Foundation has initiated a project to measure radioactivity levels in fish caught in the Barents Sea.
In order to prevent the above-mentioned scenarios, it would be best to lift the K-159 submarine—but only if it is possible to do so in a secure way. There are some very serious arguments against such a lifting operation that have to be addressed until any final conclusion can be drawn.
First of all, very little information is available as to what technical shape the two reactors are in, and to what extent the reactors and the submarine hull were damaged during the sinking and on impact with the sea floor. If the hull of the submarine and the reactors are in any way damaged, it would prove difficult to lift the submarine safely.
It must also be taken into account that the reactors on the K-159 are of the first generation of Russian naval reactors. These reactors lack a secure and effective safety system that would prevent the chain reaction in the reactors from resuming. The Russian Navy has stated that the reactors were shut down in 1989, and that prior to the attempted transportation of the vessel from Gremikha Bay to Polyarny, they were secured in a special way. Those measures that were undertaken to secure the reactors have to be investigated more closely in order to assess the reactors integrity.
In conclusion, it is the position of the Bellona Foundation that the Russian Federation should very thoroughly investigate different technical solutions for lifting the K-159 from the sea bottom in order to safely decommission the submarine. If this research reveals that raising the K-159 would be too complex and unsafe an operation, every effort should be made to secure the spent nuclear fuel in the two reactors on the sea bottom. One possibility is to build a sarcophagus around the reactors in order to minimise the risk of contamination.