§ Mr. AltonTo ask the Secretary of State for Defence (1) if he will make a statement on the phenomenon of gamma shine and its implications for the safety of naval personnel;
(2) what studies have been carried out into the possible hazardous effects of gamma shine; and if he will place such reports in the Library.
§ Mr. Archie HamiltonIn the context of submarine nuclear reactors, gamma shine is the term used to refer to the gamma radiation emitted by fission products contained within the vessel in the unlikely event of an accident. The hazardous effects of gamma radiation are well known and are documented in numerous published reports.
§ Mr. AltonTo ask the Secretary of State for Defence (1) why the Clyde area public safety scheme was revised in May 1985 and the gamma shine maximum hazard distance increased from 50 to 250m; and why the Scottish special safety scheme was similarly revised;
(2) if he will list the date of the latest revision of the special safety schemes at all ports with Z berths; and if he will state in each case the recommendations for dealing with gamma shine.
§ Mr. Archie HamiltonAll public and special safety schemes lay down a distance within which automatic countermeasures would be taken against radiation 489W hazards, including gamma shine, in the event of an accident. Monitoring equipment is in place at every berth visited by nuclear powered submarines, either permanently or for the duration of the visit, in order to detect and quantify any radiation hazard. The countermeasures are designed to ensure that radiation dose rates to personnel do not exceed the limits set by the National Radiological Protection Board for nuclear accidents. Specific measures may vary depending on the circumstances of each particular berth; they include sheltering and/or evacuation.
In addition, some safety schemes give an estimate of the extent of the hazard from gamma shine in the event of an accident. In all cases this is less than the distance within which automatic countermeasures would be taken. The estimates contained in the Clyde public safety scheme and the Scottish special safety scheme were revised in the light of NRPB recommendations in 1985, but no change to the planned countermeasures was required.
The dates of the most recent revisions of public and special safety schemes for ports with Z berths are as follows. Dates Portsmouth Special Safety Scheme October 1988 Southampton Special Safety Scheme February 1988 Devon Public Safety Scheme September 1988 Barrow Public Safety Scheme August 1988 Barry and Cardiff Special Safety Scheme September 1988 Liverpool Special Safety Scheme December 1988 Torbay Special Safety Scheme August 1988 Scotland Special Safety Scheme August 1988 Clyde Public Safety Scheme July 1988 Currently under revision Portland Special Safety Scheme August 1988 Rosyth Public Safety Scheme March 1986