Mississippi Administrative Code
Title 15 - Mississippi Department of Health
Part 21 - Division of Radiological Health
Subpart 78 - Radiological Health
Chapter 1 - REGULATIONS FOR CONTROL OF RADIATION IN MISSISSIPPI
Subchapter 11 - Licensing of Naturally Occurring Radioactive Materials (Norm)
Appendix 15-21-78-1-11-A - Acceptable Surface Contamination Levels For Norm
Current through September 24, 2024
| RADIONUCLIDEa | AVERAGEbcf | MAXIMUMbdfg | REMOVABLEbcef |
| U-nat, U-235, U-238, and associated products (including Po-210), except Ra-226, Th-230, Ac-227, and Pa-231 | 5,000 dpm alpha/100 cm2 | 15,000 dpm alpha/100 cm2 | 1,000 dpm alpha/100 cm2 |
| Transuranics, Ra-226, Ra-228, Th-230 Th-228, Pa-231, Ac-227 | 100 dpm/ 100 cm2 | 300 dpm/ 100 cm2 | 20 pm/ 100 cm2 |
| Th-nat, Th-232, Ra-223, Ra-224, U-232 | 1,000 dpm/ 100 cm2 | 3,000 dpm/ 100 cm2 | 200 dpm/ 100 cm2 |
| Beta-gamma emitters (radionuclides with decay modes other than alpha emission or spontaneous fission, including Pb-210), except others noted above. | 5,000 dpm beta, gamma/100 cm2 | 15,000 dpm beta, gamma/100 cm2 | 1,000 dpm beta, gamma/100 cm2 |
(a) Where surface contamination by both alpha and beta-gamma emitting radionuclides exists, the limits established for alpha and beta-gamma emitting radionuclides should apply independently.
(b) 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.
(c) Measurements of average contamination levels should not be averaged over more than one square meter. For objects of less surface area, the average should be derived for each object.
(d) The maximum contamination level applies to an area of not more than 100 cm2.
(e) 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 less surface area is determined, the pertinent levels should be reduced proportionally and the entire surface should be wiped.
(f) 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 mrad/hr (10 µGy/hr) at 1 cm respectively, measured through not more than 7 milligrams per square centimeter of total absorber.
(g) Equipment containing NORM shall not exceed a maximum radiation exposure level of 25 microroentgens per hour above background radiation at any accessible point.
