 INES 2 |
Intake of radioactive material by worker |
Routine samples of urine supplied under the scheduled bioassay programme at Dounreay in 1996 - and relating to operations in 1995 - have resulted in 3 cases where dose assessments from internally deposited radionuclides exceed regulatory limits. Two cases involved operations in the Equipment Maintenance and Decontamination Facility and one in the main reprocessing plant. Bioassay sampling continued throughout 1996 because a regime of sampling over time is required to increase the accuracy of the dose assessment resulting from the intakes. It is a requirement of UK regulations that the committed lifetime dose from materials deposited in the body is all charged to the dose record in the year of intake.
These samples and the subsequent analysis have indicated intakes for which application will be made to amend the dose record for 1995 as follows: One case with a committed effective dose equivalent of 244 mSv and committed dose to the bone surface of 4400 mSv; one with a committed dose equivalent of 210 mSv and a committed dose to bone surface of 3790 mSv and one with a committed effective dose equivalent of 43 mSv and committed dose to bone surface of 780 mSv. These doses compare to the legal annual limit in the Ionizing Radiations Regulations of 1985 of 50 mSv for whole body and 500 mSv for bone surface.
A corporate investigation has taken place into the safety issues arising from internal dose cases at Dounreay. This has led to detailed recommendations which are being implemented. Increased emphasis has been placed on the wearing of appropriate protective equipment for work where the possibility of internal contamination may be a hazard. Routine bioassay examinations have continued and indicate an improved position in 1996 operations.
Event date: Sun, 01-01-1995
