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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
Preventative and Mitigative Features - General preventative and mitigative measures identified in the
HAZOP for this specific scenario are listed in Table 5.1-10.
Estimated Frequency - The HAZOP 56 ranked the frequency of a design basis tornado (DBT) event as
"anticipated"(10 -1 $ f >10 -2 ). However, the DBT is based on a 1,000,000 year return interval, making the
frequency of the DBT event 1 x 10 -6 per year and the frequency bin of "extremely unlikely"
(10 -4 /yr $ f > 10 -6 /yr).
Source Term Development - A DBT event has limited potential to result in the release of hazardous
material. This assessment of the potential releases is based on the following facts:
C
The WHB, including the RH Bay and transfer complex (CUR, Hot Cell, Transfer Cell, and
Facility Cask Loading room), is DBT qualified. 58 Therefore, the WHB and its tornado doors
will protect the equipment and structures inside the WHB from the effects of a tornado that
could potentially result in release of hazardous material.
Ç
C
All tornado doors are closed at all times when RH waste is present in RH side of WHB.
The 10-160B cask is DOT Type B qualified. Therefore, the 10-160B cask will withstand the
effects of high wind and missiles generated by a tornado without the release of the contained
material.
Based on the above information and a review of the processing steps involved in 10-160B operations,
there is no identified, credible scenario in which the waste drums from a 10-160B cask are vulnerable to
damage and the release of radiological or hazardous chemical material. Therefore, since no hazardous
material is postulated to be released as the result of a DBT event, source term development and analysis
is not required.
Estimated Noninvolved Worker and MEI Consequences and Comparison to Risk Evaluation Guidelines -
No hazardous material is postulated to be released as the result of the DBT, therefore, consequence
analysis is not required.
Assessment of Immediate Worker Consequences - No hazardous material is postulated to be released as
the result of the DBT, therefore, consequence analysis is not required.
Safety, Structures, Systems, and Components - No hazardous material is postulated to be releases during
the DBT, therefore, Safety Class or Safety Significant SSCs are not required. The following input data
and assumptions are used in the analysis:
C
All tornado doors are closed at all times when RH waste is present in RH side of WHB.
C
C
The WHB is DBT qualified.
The Hot Cell is DBT qualified.
5.2-72 January 22, 2003