§ Mr. John EvansTo ask the Secretary of State for Defence when, under normal circumstances, a nuclear submarine discharges radioactive materials into the sea, how the Royal Navy takes the recommendations of the International Commission on Radiological Protection regarding dose into account when determining what levels are acceptable; and if the International Commission on Radiological Protection recommendations are used to determine acceptable levels of radiation for the safety of crew.
§ Mr. Archie HamiltonAs I said in my reply to the hon. Member on 20 March 1989, at column 477, under normal circumstances Royal Navy nuclear-powered submarines do not discharge radioactivity directly to the sea. When such discharges are made, however, the radioactivity level of the coolant water is measured and the water is discharged through a treatment plant which further reduces its radioactivity. Levels of radioactive discharges at sea are lower than agreed discharge limits for land-based installations, and it is inconceivable that they could result in a radiation dose to any individual approaching the limits recommended by the International Commission on Radiological Protection.
The International Commission on Radiological Protection recommendations concerning radiation doses 61W to workers are embodied within the Ionising Radiation Regulations 1985, and are applied on board Her Majesty's submarines.
§ Mr. John EvansTo ask the Secretary of State for Defence (1) if nuclear submarine personnel receiving radiation doses in the higher ranges above 15 mSv p. a. are generally those classified as radiation workers; and if those same radiation workers receive doses in those high ranges in consecutive years;
(2) whether the numbers of nuclear submarine personnel receiving radiation doses in various ranges provided on 20 March, Official Report, columns 477–78, include all nuclear submarine personnel; and how the doses for those personnel not designated as radiation workers, and so not subject to dosimetric assessment, are determined.
§ Mr. Archie HamiltonThe figures to which the hon. Member refers include only those submarine personnel classified as radiation workers. As I said in my reply to the hon. Member on 20 March, at column 476, Royal Navy nuclear submarine personnel are shielded from much natural radiation and the radiation doses they receive are for the most part lower than those received by members of
Number of personnel in dose ranges Year Cumulative dose (man Sieverts) 0–15 mSv 15–20 mSv 20–30 mSv 30–40 mSv 40–50 mSv Over 50 mSv Average individual dose (mSv) 1983 2.9 814 27 15 3 0 0 3.35 1982 2.1 994 11 8 1 0 0 2.08 1981 3.1 1,226 13 5 2 0 0 2.31 1980 6.6 2,473 31 8 2 0 1 2.63 1979 7.7 2,362 33 23 10 1 0 3.23 Note: mSv = millisievert.
§ Mr. John EvansTo ask the Secretary of State for Defence what recent medical surveys his Department has undertaken amongst past and present submarine service personnel or their offspring to determine whether there has been any abnormal statistical evidence of medical disorders arising from exposure of Royal Navy nuclear submarine personnel to radiation; and if he will publish the dates and the population census for such surveys.
§ Mr. Archie HamiltonAn epidemiological research programme into morbidity and mortality among submariners is currently being carried out by Medical Research Council. The study was commissioned by the Ministry of Defence and arranged through the Royal Naval Personnel Research Committee, through which the Royal Navy has regular contact with civil medical experts. The data for the survey were produced from service records.