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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
Airborne Release Fraction and Respirable Fraction - As discussed in Section 5.2.1.1, the ARF for
contaminated combustible materials which are subjected to impact and breach of the waste canister is
0.001. This value represents a bounding ARF for packaged material in a canister which fails due to
impact (DOE-HDBK-3010-94, subsection 5.2.3.2). 5 The bounding RF is 0.1 (DOE-HDBK-3010-94,
subsection 5.2.3.2). 4
The ARF for contaminated noncombustible materials which are subjected to impact and breach of the
waste canister for solids that do not undergo brittle fracture is 0.001. This value represents a bounding
ARF for packaged material in a canister which fails due to impact (DOE-HDBK-3010-94, subsection
5.3.3.2.2). 4 The bounding RF is 1.0 (DOE-HDBK-3010-94, subsection 5.2.3.2). 4
Leakpath Factor - Based on the scenario description, it is not expected that a waste canister drop in the
Underground will also disable the underground ventilation or HEPA filtration systems. Shift of the
underground ventilation system may occur manually or automatically as discussed in detail in Section
4.4.2.3. However, it is assumed that an automatic shift to filtration will not respond to mitigate a release
for this scenario. For the mitigated case, it is assumed that the CMR operator will be notified or be aware
of the accident and actuate the shift to filtration. Credit is not taken for the natural attenuation provided
by the discharge path.
Estimated non-involved worker and MEI Consequences and Comparison to Risk Evaluation Guidelines-
Based on the values for the source term variables as presented above, the worst-case, no-mitigation MEI
and noninvolved worker consequences (see Appendix E, Tables E-7, E-8, and E-9) of the LOC in the
Underground (RH4-B) are well within the radiological and non-radiological risk evaluation guidelines for
the extremely unlikely range.
Assessment of Immediate Worker Consequences- No current risk evaluation guidelines exist for the
assessment of accident consequences to immediate workers. Therefore, in the absence of guidelines, and
for conservatism, the noninvolved worker radiological guidelines are used as a reference point for the
assessment of consequences to immediate workers and the evaluation of the adequacy of the WIPP
defense-in-depth features. The worst-case consequences to the immediate worker from RH4-B (Table
E-14 and E-17) are well within the risk evaluation guidelines. Therefore, no specific additional worker
protection engineering or administrative controls beyond those already qualitatively identified as
providing defense-in-depth for the immediate worker, are needed based on the quantitative consequence
assessment results.
Safety Structures, Systems, and Components - Based on the estimated worst-case no-mitigation MEI and
noninvolved worker consequences and comparison to the risk evaluation guidelines, Safety Class or
Safety significant SSCs are not required. The following input data and assumptions are used in the
accident analysis:
C
Design of motor on the shield valve will be such that an inadvertent closure of shield valve will
not affect the containment integrity of the waste canister during its emplacement in the borehole
C
C
C
C
Design of hydraulic system will be such that the containment integrity of a misaligned waste
canister is not affected during its emplacement in the borehole
Throughput of waste canisters is 208/year which translates to 208 forklift operations per year.
Underground panel room floor will be leveled prior to storage operations
A spotter is present whenever forklift is used to transfer waste canister in the Underground
5.2-37 January 22, 2003