. "2 Remote-Handled Transuranic Waste." Characterization of Remote-Handled Transuranic Waste for the Waste Isolation Pilot Plant: Final Report. Washington, DC: The National Academies Press, 2002.
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Characterization of Remote-Handled Transuranic Waste for the Waste Isolation Pilot Plant: Final Report
Table 2.2 (see above) shows that the activity of RH-TRU waste currently in storage is approximately 660,000 curies. DOE calculated the total activity of the RH-TRU (stored plus projected) waste inventory to be approximately 1 million curies (DOE-CAO, 1996a; Appendix BIR). According to this estimate, the amount of RH-TRU curies to be emplaced in WIPP is about 20 percent of the total amount of curies from RH-TRU waste allowed by the Land Withdrawal Act (5.1 million curies). For comparison, the total activity to be emplaced in WIPP from CH- and RH-TRU waste is estimated to be 7.4 million curies, of which 6.4 million come from CH-TRU waste (DOE-CAO, 1996c; Appendix BIR).
Table 2.3 shows a comparison between the principal TRU and non-TRU radionuclides in CH and RH-TRU waste to be emplaced in WIPP. In 1995, the total activity of RH-TRU waste represented approximately 14 percent of the total activity of the TRU inventory (from CH-TRU and RH-TRU waste). However, the activity due to TRU radionuclides in RH-TRU waste corresponds only to 0.5 percent of the total TRU activity expected in WIPP. Table 2.3 also shows a comparison of the isotopic characteristics of CH- and RH-TRU waste expected inventories in WIPP. The total curie inventory in RH-TRU waste represents roughly 16 percent of the total curie inventory in CH-TRU waste but the number of TRU curies in the latter is two orders of magnitude higher than in RH-TRU waste. Only TRU radionuclides (i.e., radionuclides with a half-life greater than 20 years) have an impact on the long-term9 performance of WIPP since non-TRU radio
TABLE 2.3 Principal TRU and Non-TRU Radionuclides in WIPP Disposal Inventory
Radionuclide (half-life)
CH-TRU Waste (total curies)
RH-TRU Waste (total curies)
Ratio RH/CH
Plutonium-238 (87.7 years)
2,610,000
1,000
0.0004
Plutonium-239 (24,100 years)
785,000
10,000
0.013
Plutonium-240 (6,560 years)
210,000
5,000
0.024
Plutonium-241 (14.4 years)
2,310,000
142,000
0.061
Americium-241 (433 years)
442,000
6,000
0.014
Cesium-137 (30.2 years)
8,000
216,000
27
Barium-137m (2.6 minutes)
8,000
204,000
25.5
Cobalt-60 (5.3 years)
0
10,000
N/A
Strontium-90 (29.1 years)
7,000
209,000
30
Yttrium-90 (64 hours)
7,000
209,000
30
Total TRU curies (>20 years)
4,048,000
22,000
0.005
Total curies (TRU and non-TRU)
6,390,000
1,012,200
0.158
NOTE: Activities for RH- and CH-TRU waste were estimated in 1995, the year of inventory compilation. Activities decrease very rapidly for RH-TRU waste because of the short half-lives of its radionuclides. Total curies calculated assuming a volume of 7,080 cubic meters for RH-TRU waste and 168,500 cubic meters of CH-TRU waste. TRU radionuclides, by definition, have a half-life greater than 20 years.
SOURCE: Appendix BIR, Table 3–1 in TWBIR Rev 3. Supplemental Disposal Inventory Information, June (DOE, 1996c).
9
Long-term refers to the 10,000 years of regulatory compliance with radionuclide release limits established by the EPA in Title 40 Code of Federal Regulations Part 191 (see Chapter 3).
