DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
5.1.2.1 RH TRU Wastes
As defined in Public Law 102-579, WIPP Land Withdrawal Act, 14 the term "transuranic waste" means
waste containing more than 100 nanocuries of alpha-emitting transuranic isotopes per gram of waste,
with half lives greater than 20 years, except for: a) high-level radioactive waste; b) waste that the
Secretary has determined, with the concurrence of the Administrator, does not need the degree of
isolation required by the disposal regulations; or c) waste that the Nuclear Regulatory Commission
(NRC) has approved for disposal on a case-by-case basis in accordance with 10 CFR 61.
TRU waste is classified as either CH or RH, depending on the external dose rate at the waste container
surface. RH TRU wastes are packaged with an external surface dose rate of up to 1000 rem/hr
(10 Sv/hr). RH TRU waste decays principally by gamma and beta emission, with some alpha and
neutron emissions. Alpha emitting radionuclides result in no external radiation exposure to humans, but
are hazardous if inhaled or ingested. Since beta emissions, like alpha, have limited penetrating energy,
adequate personnel protection is provided by the waste container. Gamma and neutron radiation are
more penetrating, and require shielding for safe management and storage. RH TRU waste contains
predominantly gamma and beta-emitting radioisotopes, and closed canisters provide protection from
inhalation or ingestion.
5.1.2.1.1 RH TRU Radionuclide Inventory
The WIPP TRU Waste Baseline Inventory Report 17 (BIR), Revision 3, provides estimated volumes of
RH TRU waste to be supplied by 9 DOE waste generator and/or storage sites. The radionuclide
inventory by final waste form, stored waste volume, and waste site, as derived from a June 1996 query of
Revision 3 of the BIR database, is shown in Table A-1 of Appendix A. Table A-2 shows the Pu-239
equivalent radioactivity (PE-Ci) of the radionuclides contained the RH TRU waste to be shipped to
WIPP. (See Appendix B for a discussion on the PE-Ci concept). Table A-3 shows the radionuclide
concentration in PE-Ci/canister for each RH waste generator site as well as the stored volume and
equivalent number of canisters.
Revision 3 of the BIR 17 also provided new sampling data for the ORNL RH-TRU sludges, which showed
that the primary uranium isotope present in these sludges is U-238 (not U-235, as reported in their
previous Integrated Data Base (IDB) submittals). The uranium curies reported for RH-TRU waste in
previous ORNL IDB submittals were redistributed based on the new sludge sampling data. This
corrected the previously high estimates of U-235 in the ORNL RH-TRU waste inventory. DOE/CAO-
95-1121 17 provides additional information about RH waste radionuclide inventory. Since approximately
96.5 percent of the total RH-TRU curies is contributed by Cs-137, Sr-90, Ba-137m, Pu-241, and Y-90,
the remaining radionuclides contribute a very small fraction of the total curies for the repository.
The "Working Agreement for Consultation and Cooperation" (WACC) 15 limits the RH-TRU inventory to
approximately 7,080 cubic meters (250,000 cubic feet) (DOE State of New Mexico, 1981), while the
WIPP WACC for RH-TRU waste volumes and the WIPP Land Withdrawal Act 14 limit the activity of
RH-TRU waste allowed in WIPP to 5.1 million curies and the activity concentration of RH waste to 23
Ci/liter (Public Law, 102-579) 16 .
RH-TRU typically contains a greater proportion of fission and activation products that produce highly
penetrating radiation and a higher level of radiation at the surface of the package than CH-TRU.
5.1-4 January 22, 2003