TITLE 32: ENERGY
CHAPTER II: ILLINOIS EMERGENCY MANAGEMENT AGENCY
SUBCHAPTER b: RADIATION PROTECTION
PART 337 PHYSICAL PROTECTION OF CATEGORY 1 AND CATEGORY 2 QUANTITIES OF RADIOACTIVE MATERIAL
SECTION 337.APPENDIX A CATEGORY 1 AND CATEGORY 2 RADIOACTIVE MATERIAL



Section 337.APPENDIX A   Category 1 and Category 2 Radioactive Material

 

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.

 

 

Category 1

Category 1

Category 2

Category 2

Radioactive material

(TBq)

(Ci)

(TBq)

(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.

 

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 shall 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 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 shall be performed in metric values (i.e., TBq) and the numerator and denominator values shall be in the same units.

 

 

 

where:

 

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

 

(Source:  Amended at 48 Ill. Reg. 13701, effective August 29, 2024)