Evaluation Results

DOE-STD-3007-93

Equipment

Contingencv

Barrier

1. Too many containers/material 1. Limited to three 2" deep

pileup from seismic activity, etc. pans, two 1-liter containers,

and three used filters.

Operations are also only

performed by specially trained

process specialists, i.e., Core

team.

2. Fissionable material

2. It would be unlikely for the

overbatch

following barriers to

simultaneously fail.

a. Only precipitate from one

"run" per pan.

b. Clarifier columns limited to

a maximum of 25 g/l

fissionable liquids.

c. Fissionable liquid

concentrations known before

blending in tanks D-2401

A/B/C/D.

d. l-liter containers limited to

a maximum of 1000 grams

net weight.

e. Process design results in

clarifier column operating

volume less than 20 liters.

3. Criticality drain.

6.0

EVALUATION RESULTS

Tanks, equipment, and waste transfer activities involved with the CWTS are shown double

contingent as follows.

6.1.1 SAT Design: SATs were designed at RFETS for the critically safe storage of large

volumes of high-level fissionable solutions. The design consists of a nominal 3"annular tank

surrounded on both sides by shielding composed of a 2.5" annulus of polyethylene sandwiched

between two 1/8" annual nuclear poison regions. This shielding is fully encased by stainless steel

to assure its integrity and as a fire barrier. Reference figure 1 for a cross section view of a SAT.

Note that the robust nature of the cladded shielding precludes loss of the poison/moderator

regions, such that further verification of those regions is not required. Note also that no corrosion

of the shielding is observed.

Various monte-carlo computer calculations (KENO analyses, reference Appendix G), were

performed in support of SAT design. The shielding uses a polyethylene moderator to thermalize

5-8