NUREG-1537, Part 2 - NRC

BIEU To I.EU Col~vERSoN
MHA, the bases for their use should be validated, for example, by referring to
previous validations of the methods or by calculating some known BEU events or
conditions. This validation should demonstrate that the new'methods accurately
model reactor accident conditions.
For either case, the consequences to the health and safety of the public, the reactor
stag and the environment should be compared for the two reactors and with the
acceptance criteria for postulated MHAs at non-power reactors.
Acceptance Criteria
Acceptance criteria for the information on the MHA at non-power reactors should
be based on the following considerations: -
* The principal objectives of the MHA analysis are to compare the
consequences from the proposed LEU-fueled reactor with the existing
HEU-fueled reactor and to relate any changes in consequences with reactor
parameters or procedures that were changed to accommodate the
conversion., The performance of the reactor should not be significantly' -
decreased to accommodate the conversion.
* The initiating event for the MHA need not be credible nor evaluated, but
the progression of the scenario should be based on sound physical
principles and assumptions amenable to logical analyses.
* .The proposed LEU-fueled reactor and any ESFs should be designed to
prevent the projected MHA consequences from significantly exceeding the
consequences resulting from the existing HEU-fueled reactor.
* The radiological consequences of the LEU MHA should be shown to
exceed and envelope the consequences of all credible accidents postulated
and analyzed for that reactor. -
* 'Projected dose rates and accumulative doses to members of the public in
the unrestricted area: should not be significantly higher for the proposed
LEU-fueled reactor than for the existing HEU-fueled reactor and shall be
within acceptable limits.
Additional guidance on assumptions for MHA analyses may be found in U.S.
Atomic Energy Commission report TD-14844.
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