C.M.R. 10, 144, ch. 220, pt. N, Specific Licenses, app 144-220-N-A
AVERAGE2, 3, 6 | MAXIMUM2, 4, 6 | REMOVABLE2, 3, 5, 6 | |
Alpha | 5,000 dpm/100 cm2 | 15,000 dpm /100 cm2 | 1,000 dpm /100 cm2 |
Beta-gamma | 5,000 dpm/100 cm2 | 15,000 dpm /100 cm2 | 1,000 dpm /100 cm2 |
1 Where surface contamination by both alpha and beta-gamma emitting nuclides exists, the limits established for alpha and beta-gamma emitting nuclides should apply independently.
2 As used in this table, dpm (disintegrations per minute) means the rate of emission by radioactive material as determined by correcting the counts per minute observed by an appropriate detector for background, efficiency, and geometric factors associated with the instrumentation.
3 Measurements of average contamination level should not be averaged over more than one square meter. For objects of less surface area, the average should be derived for each object.
4 The maximum contamination level applies to an area of not more than 100 cm2.
5 The amount of removable radioactive material per 100 cm2 of surface area should be determined by wiping that area with dry filter or soft absorbent paper, applying moderate pressure, and assessing the amount of radioactive material on the wipe with an appropriate instrument of known efficiency. When removable contamination on objects of surface area A (where A is less than 100 sq. cm) is determined, the entire surface should be wiped and the contamination level multiplied by 100/A to convert to a "per 100 sq cm" basis.
6 The average and maximum radiation levels associated with surface contamination resulting from beta-gamma emitters should not exceed 0.2 mrad/hr (2 µGy/hr) at 1 cm and 1.0 mR/hr (10 µGy/hr) at 1 cm, respectively, measured through not more than 7 milligrams per square centimeter of total absorber.
C.M.R. 10, 144, ch. 220, pt. N, Specific Licenses, app 144-220-N-A