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WHC-SD-W100-TI-003 Rev. 0
to support 10 CFR 61 (NRC 1992) radioactive waste disposal regulations. The
WRAP 2A performance specification of a minimum leach index of 6.0 for all
waste forms is the same as the NRC requirements.
Leachate characteristics will also be analyzed and compared with the
design basis for performance modeling-of the mixed waste disposal facility to
ensure that the performance of the liner leachate collection system will not
be compromised. Leachate aggressiveness shall be less than that used for
EPA 9090 performance testing of the W-025 disposal trench liner system.
2.3.3 Biodegradation
The long-term durability of waste forms can be adversely affected if they
are susceptible to microbial degradation. Therefore, the waste form specimens
are tested for resistance to fungal growth ( ASTM G21)-and bacterial growth
(ASTM G22). -The-'tests provide ideal conditions for microbial growth, such as
proper moisture, temperature, and nutrients. After 21 days of incubation, the
specimen is inspected for growth and tested for compressive strength. The
.., WRAP 2A performance specification is for ng observable microbial growth and a
minimum-compressive strength of 5J00 ibf/in following the test.
2.3.4 Thermal Cycling
Thermal cycle testing is used to determine the durability of the waste
form when exposed to extremes of temperature that may be experienced during
storage, transportation, or disposal. The standard method for thermal cycling
is ASTM B-553, which involves exposing the test specimen to temperature
extremes of -40 °C to +60 °C (-40 OF to 140 °F) for a total of 30 five-hour
periods. After cyiling, the compressive strength must continue to meet the
minimum 500 lbf/in performance specification requirement.
2.3.5 Radiation Stability
Exposure of waste matrices to radiation can cause chemical changes in the
molecuiar structure, such as-radiolysis or crosslinking, which can in turn
affect the physical properties of the material. Therefore, 10 CFR 61
(NRC 1992) regulations-require that the waste form be tested to determine the
effects that long-term exposure to radiation may have on the Vaste form. The
t!RAP 2A-perfor„^aner syeci^icati-n cr is for
strength after exposure to a total gamma
NRC regulations.
a minimum *06 ibfjin` compressive
dose of 10 radiation, as required by
2.3.6 Water Immersion
Waste forms in the shallow land disposal environment will inevitably be
exposed to moisture. Depending on the type of waste and the immobilization
matrix, exposure to moisture can cause swelling, cracking, and other adverse
__--_---changes in__tha -waste formr- To e.n.sure adequ ate performance under these
conditions, the waste form specimens are immersed in water for 90 days, after
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