Worker contamination for AM-241 inhalation when manipulating a radiation detector

Within the framework of plant decommissioning workers at spent fuel pool hall, a specialized worker using "Mururoa and autonomous respiration equipment" changed the vinile cap of an underwater radiation detector. During the routine check out for radiation contamination at the working area exit, a nose frotis showed 0.048 cps of alpha particles.
The worker was administered DTPA for preventing internal contamination fixing. Afterwards he passed through a bioassay program that took several months and concluded that: a) effective dose to the whole body estimated at 31 mSv, b) internal integrated dose to bone surface 576 mSv. Dose a) is well within statutory limits, regarding dose b) bones are organs not referred to in ICRP-60, the standard to which Spain is to adhere for European Union mandate.
Justification: The on-site criterion is not applicable as no statutory limit was reached.
It is rated on the Defense in depth criterion, in application of bullet A.6 of the INES User's Manual Addendum "Events requiring medical treatment of workers" says where any surgical or medical treatment (e.g. DTPA) is necessary in order to prevent an exposure significantly in excess of an annual dose limit, the event should be rated at least at level 1 under defense in depth. Final: INES level 1

Location: VANDELLOS-1
Event date: Wed, 26-03-1997
Nuclear event report
Legenda & explanation