Neutron Absorber Sandwich

DOE-STD-3007-93

neutrons and optimize the effect of neutron absorbers located on either side of the moderator.

This configuration results in neutronic isolation of the SAT tank, thus there are no spacing

requirements. Note that this isolation also precludes seismic contingencies from tank shifting.

These analyses, contained in evaluations JNM-25 and JNM-28, became the basis for the SAT

design criteria, which is included in Appendix H.

Validation of KENO analyses in JNM-25 and JNM-28 was completed by Critical Mass

Laboratory (CML) experimentation as reported in Appendix I. Though initial design analyses

used KENOIV and CML validation used KENOV, there is no significant difference in code usage

as reported in Appendix J. Note that CML experimentation was specifically conducted to validate

poison and moderator application in the Shielded Annular Tanks, thus U235 solution was used in

the critical mass experiments. This is appropriate as cross sections for Pu and U235 solutions in

annular tanks have been previously validated in CML experiments at RFETS and within the

complex.

Figure 1

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