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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
facility cask containing a Type A (or equivalent) waste canister in this class of accident is 0.01
(DR=0.01) for direct loaded waste and 0.001 (DR =0.001) for double confined waste.
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 from the explosion 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 from the explosion (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 from the explosion
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 from the
explosion (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 fire followed by an
explosion 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-10, E-11, and E-12) of the Fire
followed by an Explosion in the Underground (RH5) are 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 RH5 (Table
E-15) are well within the risk evaluation guidelines. Therefore, no specific additional worker protection
engineering or administrative controls beyond those already qualitatively identified as providing defensein-depth
for the immediate worker, are needed based on the quantitative consequence assessment results.
Safety Structures, Systems, and Components - Based on the frequency of this accident, Safety Class or
Safety significant SSCs are not required. The following input data and assumptions are used in the
frequency analysis:
C
Throughput of waste canisters is 208/year which translates to 208 forklift operations per year.
C
C
C
C
There is not another facility cask containing a RH waste canister or any CH waste in the path of
the forklift transporting a filled facility cask to the disposal room.
RH waste canisters are vented
A spotter is present when the RH waste canister is transported by the forklift in the Underground.
Maximum volume of hydraulic oil in the HERE is # 40 gal (151.4 L).
5.2-40 January 22, 2003