§336.364. Appendix G. Acceptable Surface Contamination Levels.

Radionuclide^{1} |
Average^{2,3,6} |
Maximum^{2,4,6} |
Removable^{2,3,5,6} |

U-natural, U-235, U-238,
and associated decay products except Ra-226, Th-230, Ac-227, and Pa-231 Transuranics, Ra-223, Ra-224, Ra-226, Ra-228 Th-natural, Th-228, Th-230, Th-232, U-232, Pa-231, Ac-227, Sr-90, I-125, I-126, I-129, I-131, and I-133 Beta-gamma emitters (radionuclides with decay modes other than alpha emission or spontaneous fission) except Sr-90 and others noted above |
5,000 dpm alpha/ 100 cm ^{2}
1,000 dpm/ 100 cm ^{2}
5,000 dpm beta- gamma/ 100 cm ^{2} |
15,000 dpm alpha/ 100 cm ^{2}
3,000 dpm/ 100 cm ^{2}
15,000 dpm beta- gamma/ 100 cm ^{2} |
1,000 dpm alpha/ 100 cm ^{2}
200 dpm/ 100 cm ^{2}
1,000 dpm beta-gamma/100 cm ^{2} |

1. Where surface contamination by both alpha- and beta-gamma-emitting radionuclides
exists, the
limits established for alpha- and beta-gamma-emitting radionuclides should be applied
independently.

2. As used in this appendix, 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. Average contamination level shall not be measured over more than 1 square meter. For
objects of
less surface area, the average shall be derived for each object.

4. The maximum contamination level applies to an area of not more than 100 square
centimeters
(cm^{2}).

5. The amount of removable radioactive material per 100 cm^{2} of surface area
shall 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 less surface area is determined, the pertinent levels shall
be
reduced proportionally and the entire surface shall be wiped.

6. The average and maximum radiation levels associated with surface contamination
resulting from
beta-gamma emitters shall not exceed 0.2 millirad/hour at 1 cm and 1.0 millirad/hour at 1 cm,
respectively, measured through not more than 7 milligrams/cm^{2} of total absorber.