Print View Posted on: 30 September 2019
A licensee reported that three individuals may have been exposed to Am-241. An individual was cleaning up a small area of contamination using a high-efficiency particulate air (HEPA) filtered vacuum cleaner. The vacuum cleaner was previously used in a different area to clean up Am-241 metal. The individual turned on the vacuum, felt blow back, turned off the vacuum, and returned it back to its normal storage location. He then told a second individual to shut the doors of the room. The first individual was in the area for twenty minutes. The second individual and the radiation safety officer (RSO) were in the room for one minute. The reading on a nose swab performed on the first individual was 66,000 dpm. After removing his clothing, taking a shower and blowing his nose, additional swabs were performed. Results were 4,884 dpm from the right nostril and 1,729 dpm from the left nostril. On the second day, swab results were 67 dpm from the right nostril and 36 dpm from the left nostril. Bioassay samples were collected. Based on subsequent urine and fecal bioassay data, the intakes of three individuals equated to whole body doses of 0.128, 0.052, and 0.0042 Sv (12.8, 5.2, and 0.42 rem), respectively. The calculated committed bone doses to the individuals were 2.99, 1.22, and 0.97 Sv (299, 122, and 9.7 rem). The root cause of the event was the failure of a HEPA vacuum cleaner, inadequate procedures, and poor emergency training. The use of the vacuum cleaner in the affected area was not routine and should have not been performed. The doses received by the first and second individuals exceed the U.S. statutory limit for whole body dose of 0.05 Sv (5 rem) and committed dose equivalent of 0.5 Sv (50 rem). NRC EN53974