Each licensee shall make available to DHHS/RHS for inspection, upon reasonable notice, records kept by the licensee pertaining to its receipt, possession, use, acquisition, import, export, or transfer of category 1 or category 2 quantities of radioactive material.
Table 4038.1-Category 1 and Category 2 Threshold
The terabecquerel (TBq) values are the regulatory standard. The curie (Ci) values specified are obtained by converting from the TBq value. The curie values are provided for practical usefulness only.
Radioactive material | Category 1(TBq) | Category 1(Ci) | Category 2(TBq) | Category 2(Ci) |
Americium-241 | 60 | 1,620 | 0.6 | 16.2 |
Americium-241/Be | 60 | 1,620 | 0.6 | 16.2 |
Californium-252 | 20 | 540 | 0.2 | 5.40 |
Cobalt-60 | 30 | 810 | 0.3 | 8.10 |
Curium-244 | 50 | 1,350 | 0.5 | 13.5 |
Cesium-137 | 100 | 2,700 | 1 | 27.0 |
Gadolinium-153 | 1,000 | 27,000 | 10 | 270 |
Iridium-192 | 80 | 2,160 | 0.8 | 21.6 |
Plutonium-238 | 60 | 1,620 | 0.6 | 16.2 |
Plutonium-239/Be | 60 | 1,620 | 0.6 | 16.2 |
Promethium-147 | 40,000 | 1,080,000 | 400 | 10,800 |
Radium-226 | 40 | 1,080 | 0.4 | 10.8 |
Selenium-75 | 200 | 5,400 | 2 | 54.0 |
Strontium-90 | 1,000 | 27,000 | 10 | 270 |
Thulium-170 | 20,000 | 540,000 | 200 | 5,400 |
Ytterbium-169 | 300 | 8,100 | 3 | 81.0 |
Note: Calculations Concerning Multiple Sources or Multiple Radionuclides
The "sum of fractions" methodology for evaluating combinations of multiple sources or multiple radionuclides is to be used in determining whether a location meets or exceeds the threshold and is thus subject to the requirements of this part.
Calculations must be performed in metric values, i.e., TBq, and the numerator and denominator values must be in the same units.
R1 = total activity for radionuclide 1
R2 = total activity for radionuclide 2
RN = total activity for radionuclide n
AR1 = activity threshold for radionuclide 1
AR2 = activity threshold for radionuclide 2
ARN = activity threshold for radionuclide n
N.H. Admin. Code § He-P 4038.31