Discussion of Contingencies

DOE-STD-3007-93

All calculations documented in this evaluation were performed on an IBM PS/2 Model 60

operating under DOS Version 3.10 with Version 1.0 of the IBM PRO FORTRAN Compiler.

Configuration Release 3.0 of the ANISN/PC code was used for the evaluation and was verified

for proper operation on the IBM PS/2 Model 60 computational platform by repeating the 21

sample problems as detailed in the Software Quality Assurance Package. A more detailed

description of this verification effort is given in Reference 8.

As required by DOE1, "The double contingency principle shall be used as a minimum to

ensure that a criticality accident is an extremely unlikely event. Compliance with the double

contingency principle requires that two unlikely, independent, and concurrent changes in process

or system conditions occur before a criticality accident is possible."

As shown in Table 2 and the results in Section 6.0, the requirements of the double

contingency principle are met for the proposed shipment of radioactive waste within the

boundaries of the INEL. The barriers associated with these contingencies (i.e., accident

prevention and fissile inventory verification measures) are yet to be determined.

Table 2. Contingency Analysis.

Contingencies (unlikely events)

No.

Description

Barriers

An accident that causes all plutonium in a shipment

Accident prevention measures

to form into a homogenous mixture of polyethylene

(to be determined)

(60 vol.%), water (40 vol.%), and Pu-239 in

optimally moderated and reflected spherical

geometry. (This scenario is considered incredible

by itself.)

Exceeding the operating mass limit (160 FGE of

Fissile mass verification

Pu-239) by a factor of at least 2.5 (405 FGE of Pu-

measures (to be determined)

239 can result in a k-effective value of 1.0 under

optimally moderated, reflected, and configured

conditions). Waste shipments will typically contain

only a few grams Pu per shipment.

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