Classification of waste for near surface disposal.

1. A. Considerations. Determination of the classification of radioactive waste involves two considerations. First, consideration must be given to the concentration of long-lived radionuclides (and their shorter-lived precursors) whose potential hazard will persist long after such precautions as institutional controls, improved waste form, and deeper disposal have ceased to be effective. These precautions delay the time when long-lived radionuclides could cause exposures. In addition, the magnitude of the potential dose is limited by the concentration and availability of the radionuclide at the time of exposure. Second, consideration must be given to the concentration of shorter-lived radionuclides for which requirements in institutional controls, waste form and disposal methods are effective. Additional consideration must be given to ensure that such waste is not regulated by RCRA.

2. B. Classes of waste.

   (1) Class A waste is waste that is usually segregated from other waste classes at the disposal site. The physical form and characteristics of class A waste must meet the minimum requirements set forth in Subsection A of 20.3.13.1325 NMAC. If class A waste also meets the stability requirements set forth in Subsection B of 20.3.13.1325 NMAC, it is not necessary to segregate the waste for disposal.

   (2) Class B waste is waste that must meet more rigorous requirements of waste form to ensure stability after disposal. The physical form and characteristics of class B waste must meet both the minimum and stability requirements set forth in 20.3.13.1325 NMAC.

   (3) Class C waste is waste that not only must meet more rigorous requirements on waste form to ensure stability but also requires additional measures at the disposal facility to protect against inadvertent intrusion. The physical form and characteristics of class C waste must meet both the minimum and stability requirements set forth in 20.3.13.1325 NMAC.

3. C. Classification determined by long-lived radionuclides. If radioactive waste contains only radionuclides listed in table 1324.1, classification shall be determined as follows:

   (1) if the concentration does not exceed 0.1 times the value in table 1324.1, the waste is class A;

   (2) if the concentration exceeds 0.1 times the value in table 1324.1 but does not exceed the value in table 1324.1, the waste is class C;

   (3) if the concentration exceeds the value in table 1324.1, the waste is not generally acceptable for near-surface disposal; and

   (4) for wastes containing mixtures of radionuclides listed in table 1324.1, the total concentration shall be determined by the sum of fractions rule described in Subsection G of 20.3.13.1324 NMAC.

   TABLE 1324.1 Radionuclide Concentration Curies per Cubic Meter(M³) C-14 8 C-14 in activated metal 80 N-59 in activated metal 220 Nb-94 in activated metal 0.2 Tc-99 3 I-129 0.08 Alpha emitting transuranic nuclides with half life greater than 5 years ¹100 Pu-241 ¹3,500 Cm-242 ¹20,000 Ra-226 100 NOTE: To convert the Ci/M³ to gigabecquerel (Gbq) per cubic meter, multiply the Ci/M³ by 37. ¹Units are nanocuries per gram.

   TABLE 1324.1

   Radionuclide

   Concentration

   Curies per Cubic Meter(M³)

   C-14

   8

   C-14 in activated metal

   80

   N-59 in activated metal

   220

   Nb-94 in activated metal

   0.2

   Tc-99

   3

   I-129

   0.08

   Alpha emitting transuranic nuclides with half life greater than 5 years

   ¹100

   Pu-241

   ¹3,500

   Cm-242

   ¹20,000

   Ra-226

   100

   NOTE: To convert the Ci/M³ to gigabecquerel (Gbq) per cubic meter, multiply the Ci/M³ by 37.

   ¹Units are nanocuries per gram.

4. D. Classification determined by short-lived radionuclides. If radioactive waste does not contain any of the radionuclides listed in table 1324.1, classification shall be determined based on the concentration shown in table 1324.2. However, as specified in Subsection F of 20.3.13.1324 NMAC, if radioactive waste does not contain any nuclides listed in either table 1324.1 or table 1324.2, it is class A.

   (1) If the concentration does not exceed the value in table 1324.2, column 1, the waste is class A.

   (2) If the concentration exceeds the value in table 1324.2, column 1, but does not exceed the value in column 2, the waste is class B.

   (3) If the concentration exceeds the value in table 1324.2, column 2, but does not exceed the value in column 3, the waste is class C.

   (4) If the concentration exceeds the value in table 1324.2, column 3, the waste is not generally acceptable for near-surface disposal.

   (5) For wastes containing mixtures of the nuclides listed in table 1324.2, the total concentration shall be determined by the sum of fractions rule described in Subsection G of 20.3.13.1324 NMAC.

   TABLE 1324.2 Radionuclide Concentration, Curies Per Cubic Meter Col. 1 Col. 2 Col. 3 Total of all nuclides with less than 5 year Half-life 700 (¹) (¹) H-3 40 (¹) (¹) Co-60 700 (¹) (¹) Ni-63 3.5 70 700 Ni-63 in activated metal 35 700 7000 Sr-90 0.04 150 7000 Cs-137 1 44 4600 NOTE: To convert the Ci/M³ to gigabecquerel (GBq) per cubic meter, multiple the C/M³ by 37.

   TABLE 1324.2

   Radionuclide

   Concentration, Curies Per Cubic Meter

   Col. 1

   Col. 2

   Col. 3

   Total of all nuclides with less than 5 year

   Half-life

   700

   (¹)

   (¹)

   H-3

   40

   (¹)

   (¹)

   Co-60

   700

   (¹)

   (¹)

   Ni-63

   3.5

   70

   700

   Ni-63 in activated metal

   35

   700

   7000

   Sr-90

   0.04

   150

   7000

   Cs-137

   1

   44

   4600

   NOTE: To convert the Ci/M³ to gigabecquerel (GBq) per cubic meter, multiple the C/M³ by 37.

5. E. Classification determined by both long and short-lived radionuclides. If radioactive waste contains a mixture of radionuclides, some of which are listed in table 1324.1, and some of which are listed in table 1324.2, classification shall be determined as follows.

   (1) If the concentration of a nuclide listed in table 1324.1 does not exceed 0.1 times the value listed in table 1324.1, the class shall be that determined by the concentration of nuclides in table 1324.2.

   (2) If the concentration of a nuclide listed in table 1324.1 exceeds 0.1 times the value listed in table 1324.1 but does not exceed the value in table 1324.1, the waste shall be class C, provided the concentration of nuclides listed in table 1324.2 does not exceed the value shown in column 3 of table 1324.2.

6. F. Classification of wastes with radionuclides, other than those listed in tables 1324.1 and 1324.2. If radioactive waste does not contain any nuclides listed in either table 1324.1 or table 1324.2, it is class A.
7. G. The sum of the fractions rule for mixtures of radionuclides. For determining classification for waste that contains a mixture of radionuclides, it is necessary to determine the sum of fractions by dividing each nuclide’s concentration by the appropriate limit and adding the resulting values. The appropriate limits must all be taken from the same column of the same table. The sum of the fractions for the column must be less than 1.0 if the waste class is to be determined by that column. Example: A waste contains Sr-90 in a concentration of 50 Ci/m³ and Cs-137 in a concentration of 22 Ci/m³. Since the concentrations both exceed the values in column 1 of table 1324.2, they must be compared to column 2 values. For Sr-90 fraction 50/150=0.33; for Cs-137 fraction, 22/44=0.5; the sum of the fractions = 0.83. Since the sum is less than 1.0, the waste is class B.

8. H. Determination of concentrations in wastes. The concentration of a radionuclide may be determined by indirect methods, such as use of scaling factors which relate the inferred concentration of one radionuclide to another that is measured, or radionuclide material accountability, if there is reasonable assurance that the indirect methods can be correlated with actual measurements. The concentration of a radionuclide may be averaged over the volume of the waste, or weight of the waste if the units are expressed as nanocuries per gram.

   [5-3-95; 20.3.13.1324 NMAC - Rn, 20 NMAC 3.1.13.1324, 04/15/2004]