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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
General areas of concern identified include:
Fires
Explosions
Internal and external conditions that may lead to a breach or rupture of the 10-160B cask, drums,
facility canister and 72B waste canisters which could result in the airborne release of radiological
materials.
Direct radiological exposure of personnel to high radiation and airborne radiological activity.
Worker injury or fatality.
External waste container surface contamination and need for decontamination.
Major damage to equipment and facility.
Major disruption of process operations.
The consequences of each deviation were developed without mitigating systems in place (with the
exception of the confinement and/or shielding provided by the casks, canisters, and the WHB) and are
listed in Appendix C. Appendix C also provides a listing, identified by the HAZOP Team, of the
substantial safeguards currently existing at the WIPP facility to reduce the likelihood of the identified
deviations and to mitigate the consequences of such deviations. Identified safeguards include design
features such as radiation shielding, building structure, ventilation system, and casks; administrative
control features such as procedures, worker training, preventive maintenance and inspection programs,
and the WIPP RH WAC. 10
5.1.4.2 Selection of RH Potential Accidents
To assess the relative radiological risk to the offsite individual, the frequency and radiological
consequence rankings for that receptor were "binned" using the Risk Ranking Matrix given in
Table 5.1-7. The resulting risk in each case was categorized as acceptable ( having low risk), moderate,
or high as defined on the matrix. Those deviations which had an offsite ranking with a frequency and
consequence combination that is in the matrix area, or "bin", indicating low risk and concern were
excluded from further consideration for quantitative evaluation. The events which impact the offsite
public and have risk that falls in the darker shaded area on the risk matrix should be considered
"situations of major concern" as described in DOE-STD-3009-94, 3 with sufficiently high risk that these
events might be considered "unique" and individual examination might be used in the accident analysis
phase. The events that impact the offsite individual and fall in the lighter shaded area in Table 5.1-7 are
considered "situations of moderate concern" that yield a subset of "representative" events needing further
examination. Representative events bound a number of similar events of lesser risk (the worst fire for a
number of similar fires). At least one event from each of the event types is considered representative.
Representative events are examined only to the extent that they are not bounded by unique events.
Table 5.1-8 lists the deviations considered to have a "radiological rank" which indicated moderate
(lighter shaded area on Table 5.1-7) or high risk (darker shaded area on Table 5.1-7) to the offsite
individual as determined by the binning process. The 17 hazardous events were selected as potential
candidates for quantitative analysis. The frequency of an aircraft crash into WHB (hazardous event 13-7
in Table C-1) is beyond extremely unlikely based on the physical size of the WHB and the frequency of
the flights within 5 miles of WIPP 24 . The consequences of the Underground Roof Fall 31 (hazardous event
14-1 in Table C-1) are negligible to the public and onsite worker, and low to immediate worker because
of the storage location and design of the RH 72-B waste canister and the facility canister.
5.1-16 January 22, 2003