§ Mr. Alton
To ask the Secretary of State for Defence (1) what incidents have been reported involving pressurised water reactors in nuclear submarines releasing gas from their cooling systems into the atmosphere;
(2) what information he has on what radionuclides would be produced if air contaminated the cooling system of a pressurised water reactor in a nuclear submarine.
§ Mr. Archie Hamilton
The primary coolant water in submarine pressurised water reactors inevitably contains a very small amount of air. The dominant nuclides which form in the dissolved air are nitrogen-16, nitrogen-17 and argon-41, with half-lives of 7.1 seconds, 14.4 seconds and 1.8 hours respectively. Argon, which accumulates over time, is routinely released when necessary, with appropriate safety precautions. No Royal Navy submarine has ever been involved in an incident causing any radiological hazard to service men, base personnel or members of the public.