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Volume 173: debated on Thursday 24 May 1990

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To ask the Secretary of State for Defence in which year neutron emission resulting in underassessment of the radiation dose exposure equivalent of Coulport personnel from the Chevaline warhead during transportation or storage was first recorded; and if he will make a statement.

The under-assessment of the neutron and over-assessment of gamma components of radiation dose from Chevaline warheads in Coulport started in 1979. No one working in the nuclear weapon areas during the last 10 years will have a corrected annual dose greater than 20 per cent. of the annual dose limit.

Since the building environmental review plan in 1989, separate dosimeters have been introduced to monitor gamma and neutron radiation respectively.

To ask the Secretary of State for Defence what is the maximum total radiation dose registered in the Institute of Naval Medicine's records held at Alverstoke for any past or present Rosyth dockyard workers; for what period it was accrued; and what are the 20 highest doses recorded.

The maximum lifetime total radiation dose for any past or present Rosyth dockyard worker registered in the defence radiological protection service's computerised record-keeping system is 597·75 mSv. This total dose accrued over the period 17 December 1964 to 30 November 1989.The 20 highest radiation doses recorded for workers so registered are as follows:

Cumulative Radiation Exposures (mSv)

  • 597·75
  • 595·89
  • 571·35
  • 563·78
  • 534·67
  • 515·59
  • 482·52
  • 480·59
  • 479·20
  • 478·22
  • 474·52
  • 472·18
  • 463·02
  • 452·68
  • 439·11
  • 428·03
  • 427·14
  • 420·07
  • 414·16
  • 410·13

Radiation dose records for personnel leaving employment before 1979 are not held on computer compatible media, and therefore any large-scale analysis, even where possible, could be conducted only at disproportionate cost.