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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
There are two applicable ARFs for materials exposed to impact stresses generated by dropping an object
on the waste drums or puncturing the waste drums given in DOE-HDBK-3010-94. 4 One ARF is for
combustible solid packaged waste (CARF) and one is for non-combustible solid packaged waste
(NCARF). In this analysis, the waste in the drums processed through the Hot Cell and RH Bay is
assumed to contain both combustible and non-combustible solid waste. As a conservative, bounding
assumption, it is assumed that the solid waste in the drums consists of 5 percent combustible waste
(CF = 0.05) and 95 percent non-combustible waste (NCF = 0.95) for the LOC events. The combination
of ARF and RF for non-combustibles exposed to impact stresses is higher than for combustibles. This is
consistent with the assumptions used in the accident analysis for the CH waste reported in the WIPP CH
SAR 6 and with the assumptions used in the accident analysis for the 72B cask.
In addition to being either combustible or non-combustible, the hazardous materials in the waste drums
may be either in a gaseous, liquid or solid form. All of the radiological material in the waste is assumed
to be in a solid form. The non-radiological hazardous materials may be either in a gaseous, liquid or
solid form. The hazardous materials that are in gaseous form are the VOCs shown in Table 5.1-2. It is
assumed that the VOCs are instantaneously released from a breached waste drum. The VOCs have an
ARF of 1.0 regardless of whether they are combustible or non-combustible.
For the liquid hazardous materials, the ARF is developed based on the assumption that the material is not
in a free-standing form. In other words, the liquid is assumed to be absorbed into solid waste material
such as rags, kim wipes or other material. The liquid hazardous material is assumed to respond to the
accident stresses in the same manner as the solid material in which it is absorbed.
For the non-gaseous radiological and hazardous materials, the ARF depends on whether or not the
material is combustible. The bounding value of CARF from DOE-HDBK-3010-94 4 , Section 5.2.3.2 for
contaminated combustible material which is subjected to impact and breach of the waste drum is
1.00E-03 (CARF = 1.00E-03).
For the non-combustible non-gaseous waste material, the bounding value for NCARF is taken directly
from DOE-HDBK-3010-94 4 , Section 5.3.3.2.2, which gives a bounding value of 1.0E-03 for materials
that do not undergo brittle fracture (NCARF = 1.0E-03).
NC3 - Respirable Fraction
The respirable fractions for the combustible non-gaseous material (CRF) and non-combustible
non-gaseous material (NCRF) are taken directly from DOE-HDBK-3010-94 4 . The bounding CRF is 0.1
(page 5-4 4 ) and the bounding NCRF is 1.0 (page 5-7 4 ). For the VOCs, the CRF and NCRF are both set
equal to 1.0. Since the VOCs are assumed to be in gaseous form, all of the VOCs will be respirable.
NC3 - Leak Path Factor
For the LOC accident scenarios that occur in the Hot Cell (NC3-A, NC3-C, and NC3-E) the hazardous
material is released to the Hot Cell atmosphere which is exhausted through a HEPA filter bank in the
filter gallery and then to the exhaust header. As discussed in Section 5.2.1, the LPF is 1.0E-06 for the
mitigated case and 1.0 for the no-mitigation case.
For the LOC accident scenarios that occur outside the Hot Cell (NC3-B, NC3-D, NC3-F, NC3-G, and
NC3-H) the release of the hazardous material is to the WHB atmosphere. The WHB atmosphere is
exhausted through a HEPA filter bank in the exhaust fan mechanical room and then to the exhaust
header. The LPF is 1.0E-06 for the mitigated case and 1.0 for the no-mitigation case. The LPF for the
VOCs is 1.0 even for the mitigated case.
5.2-53 January 22, 2003