NUREG-1537, Part 2 - NRC

APPENDvx 18.1
I *
Acceptance Criteria ,)
Acceptance Criteria for the scenario and consequences of the postulated LOCA
should be based on the following considerations: The initiating event and
scenarios for the existing BIEU- and the proposed LEU-fueled reactor should be
siilar, unless the conversion requires significant changes in facility design or
operating characteristics. If the scenarios are similar, similar assu'mptions and
methods-of analysis should be used. 'The analysis should show that the LEU-fueled
reactor systems and fuel are designed to ensure that fuel integrity is not lost and
that potential risk of damage to fuel or systems is not significantly increased by the
conversion.
If changes in reactor systems, fuel, or operating characteristics required by the
conversion are significant, a new scenario may be required as well as a different
analytical method. The licensee should validate any significant differences in these
factors by comparison with the HEU-fueled reactor and any applicable analyses. If
different analyses are required, they should show that the LEU-fueled reactor fuel
and systemn designs are sufficient to show that'any consequences of the LOCA are
within acceptance criteria for the HEU-fueled reactor. The information should
include reference to applicable technical specifications that ensure operability and
availability of any required ECCS for which credit is taken in the analyses.'
Review Procedures >
The reviewer'should compare the information provided to-determine if there are
significant differences in the postulated LOCA events for the HEU- and LEUfueled
reactors. The reviewer should find any differences and trace the scenarios
and analyses from initiation of the event until conditions are stabiliied. The
information should justify changes in reactor systems or operating characteristics
designed to mitigate consequences to fuel, the reactor, and the public.
The reviewer should compare the analyzed consequences for the HEU- and LEUfiueled
reactors and should compare the LEU consequences with the acceptance
critera
Ewluation Findings
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-coolant initiating event and scenario
for the proposed LEU-fueled reactor as previously postulated for the
licensed HEU core (e.g., the instantaneous, total loss of coolant). The
NUREG.1S37,PAR~T2 50 REv. O, 2/96
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