Code of Massachusetts Regulations › 105 CMR - DEPARTMENT OF PUBLIC HEALTH › Title 105 CMR 120.000 - The Control of Radiation › PHYSICAL PROTECTION IN TRANSIT › Section 120.080 - Apendix A - Category 1 and Category 2 Radioactive Materials

Current through Register 1525, July 5, 2024
Table 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
				  105
				  CMR 120.050 through 120.080.
I. If multiple sources of the same
				radionuclide and/or multiple radionuclides are aggregated at a location, the
				sum of the ratios of the total activity of each of the radionuclides must be
				determined to verify whether the activity at the location is less than the
				category 1 or category 2 thresholds of Table 1, as appropriate. If the
				calculated sum of the ratios, using the equation below, is greater than or
				equal to 1.0, then the applicable requirements of
				105
				CMR 120.050 through 120.080 apply.
II. First determine the total activity for
				each radionuclide from Table 1. This is done by adding the activity of each
				individual source, material in any device, and any loose or bulk material that
				contains the radionuclide. Then use the equation below to calculate the sum of
				the ratios by inserting the total activity of the applicable radionuclides from
				Table 1 in the numerator of the equation and the corresponding threshold
				activity from Table 1 in the denominator of the equation. 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
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