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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
The magnitude of hazardous materials that can be involved in an accident leading to a release is very
limited. The radioactive material is delivered to the site in closed containers, and the waste handling
operations are designed to maintain that integrity throughout the entire process required to safely emplace
those containers in the site’s underground waste disposal rooms. Inventory limits on individual
containers ensure that heat generated by radioactive decay can be easily dissipated by passive
mechanisms. Finally, only a limited number of waste containers have the possibility of being breached
as a result of any one accident initiating event. As a result, the consequences of unmitigated releases
from all accidents hypothesized in Chapter 5, including those initiated by human error, do not produce
significant offsite health consequences.
The facility has no complex system requirements to maintain an acceptable level of risk. The facility is
designed to minimize the presence and impact of other energy sources that could provide the heat or
driving force to disperse hazardous materials. When something unusual happens during normal
operations, such as support systems becoming unavailable, waste handling can be simply stopped and
personnel evacuated until an acceptable operating condition is reestablished.
Should an initiating event occur that breaches the waste containers, the plant design permits the
immediate cessation of activity and isolation of the area where the breach occurs. Once isolation is
achieved, there is no driving force within the waste or waste handling area that could result in a release of
the waste material. Consequently, sufficient time is available to thoroughly plan and prepare for the
remediation process prior to initiating decontamination and recovery actions.
Human factors considered in this SAR is limited to that time necessary to properly emplace the
transuranic waste designated for disposal at WIPP. The operations will be straightforward,
proceduralized, and consistent. Moreover, they will continue for only the period of time needed to
complete the disposal process. Once a panel is filled and sealed off, the natural properties of the salt and
the location of the mine combine to provide passive isolation of the waste from the environment. The
potential for human intrusion after the facility closure is beyond the scope of the human factors
evaluation considered here.
Conclusion
It is concluded from the hazards and accident analyses in this SAR that the design basis of the WIPP RH
TRU waste handling systems are adequate in response to postulated range of RH TRU normal operations
and accident conditions for the facility.
5.2.4.2 Analysis of Beyond the Design Basis Accidents
Operational Events
An evaluation of 72-B cask and 10-160B cask operational accidents "beyond" design basis accident
(BDBA) is conducted to provide perspective of the residual risk associated with the operation of the
facility. As discussed in DOE-STD-3009-94 1 , BDBAs are simply those operational accidents with more
severe conditions or equipment failure. Based on the analyses in Section 5.2.3, the operational accident
scenario involving potential consequences to the non-involved worker, MEI, and immediate worker,
whose frequency is less than 1E-06/yr is RH5, Fire followed by Explosion.
5.2-79 January 22, 2003