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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
event. Since it is assumed that all of the radiological material from a 10-160B cask is located in a single
waste drum, the five drums impacted is equivalent to assuming the one drum containing all of the
radiological material is damaged. Therefore, for the radiological source term analysis, it will be assumed
that only one waste drum is breached by the road cask falling over in the RH bay, resulting in a release of
the radiological material (CD = 1). The MAR is 20 PE-Ci (CD x CI) for this event.
As with the radiological MAR, in determining the non-radiological MAR it is assumed that five waste
drums are subject to the effects of the road cask falling over during movement. Therefore, it is assumed
that the non-radiological MAR is the content of five waste drums (CD = 5) or 1215 pounds.
The DR is determined based on the amount of damage the waste drum receives as a result of the impact
and how much of the contents are exposed as a result. Since the drop could be greater than four feet in
height, it is possible for the waste drums to be damaged. From section 5.2.1.1, the DR for drops of waste
containers from the heights greater than five feet but less than or equal to ten feet is 0.025. The DR for
this event is 0.025.
Estimated Noninvolved 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 of NC3-H are well within the radiological (Appendix E Tables
E-52 and E-53) and non-radiological (Tables E-55 and E-56) 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 and non-radiological guidelines for the extremely
unlikely range 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 NC3-H (Appendix E Tables E-54 and E-57) 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.
NC3-I Toxic Gas Generation in Hot Cell Accident Scenario:
At the time the 10-160B HAZOP 56 was performed, the facility canister design required the lid to be
welded to the canister body. The canister design was changed so that the lid mechanically locks to the
canister body and welding is no longer performed. Hazardous event 11D-3 postulated that ultraviolet
light from the welding activity caused the head space gases in the facility canister to be converted into
phosgene gas (toxic) which is released into the Hot Cell. Since welding is no longer performed, no
further analysis will be performed on the scenario.
NC3-Safety Structures, Systems, and Components
Based on the source term analysis for this accident, Safety Class or Safety Significant SSCs are not
required. The following input data and assumptions are used in the frequency and source term analyses:
C
The radiological inventory of a 10-160B cask is limited to 20 PE-Ci.
C
C
The hazardous chemical inventory in the RH waste is the same as for the CH waste.
The maximum loading of an RH waste drum is 243 lbs of hazardous material.
5.2-65 January 22, 2003