NUREG-1537, Part 2 - NRC

Evaluation Findings
BEU To LEU ComvERasoN
This section of the SAR should contain sufficient information to support one of the
following type of conclusions, which will be included in the staffs safety
evaluation report:
The licensee assumed the same loss-of-flow initiating event and scenario
fbr the LEU-fueled reactor as previously postulated for the licensed BEUfueled
reactor. The methods and assumptions are applicable to and
acceptable for the proposed LEU-fueled reactor. The safety analysis
demonstrates that the fuel and cladding temperatures are not significantly
increased to the point of potential fuel damage by the conversion of the
core from HEU to LEU fuel. The conversion'does not increase the
likelihood that fuel element integrity will be lost, nor that fission products
will be released, and, therefore,' the health and safety risk to 'the public from
the postulated loss of flow accident should not increase. '
or
* The licensee assumed a loss-of-flow initiating event and scenario applicable
to the LEU core and reactor. The methods and assumptions are
accptable. The safety analysis demonstrates that the consequences of the
event meet the acceptance criteria for the BEU core and reactor.
Therefore, there is reasonable assurance that no undue risk will result to
the health and safety of theipublic from the conversion to LEU fuel as a
result of the postulated LOFA.
13.4 Other Accidents
The accidents discussed above for non-power reactors are postulated as the
limiting accidents. However, in certain reactors, other accidents may be at least as
important. These other accidents might include leakage of coolant into the
cladding with a resulting steam pressure failure of the cladding, failure of a fueled
or non-fueled experiment, physical damage to 'the core, or mechanical
displicenent of fuel. Misplaced experiments, m'ishandling of fuel, loss of normal
electrical power, external 'events, and mishandling or mlfunction of specific
equipment are other potential accidents which may need to be considered. If these
accidents are discussed in the HEU SAR, or if their possibility exists in theLEU
core, they must be addressed in the conversion safety analysis. The general
methodology used to review the specific accidents discussed in this chapter will be
useful in the review of these 'other' accidents.
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