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

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 5
Event 12E-3 postulates inadvertent movement of the Hot Cell crane while lowering the facility canister
into the Transfer Cell and damaging the canister. The causes of this event are mechanical-electrical
failure, control system failure, and human error. The frequency of event 12E-3 is a function of the
number of facility canisters processed through the Hot Cell in a year and the probability of spurious
movement of the Hot Cell crane while the canister is being moved into the Transfer Cell and the
probability that the resulting impact ruptures the canister. 693 facility canisters will be processed through
the Hot Cell and Transfer Cell in a year. The spurious movement of the Hot Cell crane could be the
result of either human error or equipment failure. However, EEG-74 64 indicates that 90 to 95 percent of
all crane incidents are caused by operator error. For this analysis, it is assumed that the spurious
movement of the crane is due to an operator error. It is also assumed that the error is equivalent to the
failure to follow a clear, unambiguous procedure in operating the crane. Table D-1 of the WIPP CH
SAR 6 provides a probability of 1E-03 for failure to follow a clear, unambiguous procedure.
EANL/EAD/TM-29 63 provides estimates of the conditional probability of rupture of a waste drum due to
impact during waste handling operations of from 1E-2 to 2E-3. Since the facility canister is more robust
than a waste drum, it would be less likely to breach from an impact than a waste drum. Therefore, the
lower value of 2.00E-03 is assumed to apply in this case. The frequency of event 12E-3 is: 693
transfers/yr * 1.00E-03 * 2.00E-03 = 1.4E-03/yr or "unlikely" (10 -2 /yr $frequency >10 -4 /yr).
Hazardous event 12E-4 postulates inadvertent movement of the shuttle car with the facility canister
partially lowered. The causes of this event are mechanical-electrical failure or shuttle car control system
failure, human error and interlock failure (shuttle car is interlocked with shield valve). The frequency of
event 12E-4 is a function of the number of facility canisters processed through the Hot Cell in a year and
the probability of spurious movement of the shuttle car during placement of the canister. 693 facility
canisters will be processed through the Hot Cell and Transfer Cell in a year. As discussed in Section
5.2.3.3, the probability of the shuttle car moving while a lift is occurring is 3.30E-12. The frequency of
event 12E-4 is: 693 lifts/yr * 3.30E-12 = 2.3E-10/yr or "beyond extremely unlikely" (10 -6 /yr $frequency).
Hazardous event 14B-1 postulates the robotic arm breaches the facility canister during a contamination
survey. The causes of this event are robotic control equipment failure. The frequency of event 14B-1 is
a function of the number of facility canisters processed per year, the probability of an error by the
operator while using the robotic are such that the arm strikes a facility canister, and the probability that a
canister is breached when it is struck by the arm. Upon closer examination, it has been determined by the
vendor 67 that the robotic arm is designed such that it is not capable of puncturing a facility canister and
the drums it contains. Further analysis of this event is not required and is classified as "beyond
extremely unlikely" (10 -6 /yr $frequency).
Since the individual events that form NC3-F has a frequency either in the "unlikely" (10 -2 /yr $frequency
> 10 -4 /yr), or "beyond extremely unlikely" (10 -6 /yr $frequency) ranges, the consequences of NC3-F are
compared against the Evaluation Guidelines for "unlikely" frequency range.
As discussed previously, it is assumed that the entire 20 PE-Ci inventory is located in a single waste
drum (CI = 20 PE-Ci). This event involves breaching a loaded facility canister inside the Transfer Cell.
The loaded Facility canister contains three waste drums, all of which could be breached in this vent. As
discussed in Section 5.2.1.1, it is assumed that all three drums breached in a facility canister each contain
the maximum radiological contents of a 10-160B cask. Therefore, for this event the CD is 3 and the
MAR is 60 PE-Ci (CD x CI).
To determine the non-radiological MAR, it is assumed that three waste drums in the Transfer Cell are
breached. Therefore, the non-radiological MAR is the content of three waste drums (CD = 3). The
non-radiological MAR is limited to the hazardous material content of three waste drums or 729 pounds.
5.2-62 January 22, 2003