NUREG-1537, Part 2 - NRC

APPENDIX 18.1
operation and shutdown would not be compromised by changes in thermalhydraulic
characteristics.
The bases of any proposed changes in the technical specifications should be
developed to ensure that the reactor can be safely operated under normal
and transient conditions under all of the allowed combinations of thermalhydraulic
parameters.
Review Procedures
The reviewer should verify that the design bases and safety criteria applicable to
the BEU-fueled reactor have been analyzed and compared for the proposed LEUfueled
reactor. This review should also include the proposed changes in the
technical specifications to ensure that they are acceptable in regard to SLs, LSSSs,
and LCOs.
The reviewer should compare the thermal-hydraulic analysis of the HEU core to
that of the LEU core. The reviewer should confirm that (1) the basic assumptions
made in the analyses are appropriate, (2) the analysis methods are applicable by
showing comparisons between measured values for the HEU core and the analytic
results for that core, (3) there is not an unexplained or unwarranted interpolation
or extrapolation of the HEU thermal-hydraulic design, (4) the thermal-hydraulic
design meets the acceptance criteria, and (5) the conclusions drawn about the
LEU-fueled reactor are acceptable. The reviewer should verify that any significant
changes in thermal-hydraulic parameters are required by the conversion from HEU
to IEU.
The proposed LEU startup test program should be reviewed to confirm the
thermal-hydraulic analysis predictions will be verified during LEU core startup. It
should be reviewed to ensure that sufficient information has been provided to
identif clearly the test objecfives, methods of testing, and acceptance criteria.
The proposed technical specifications that relate to the core thermal-hydraulic and
the reactor coolant system should be evaluated. This evaliation should cover all
SLs and bases that could affect the thermial-hydraulic performance of the core.
The LSSSs should be reviewed to ascertain that acceptable margins exist between
the values at which reactor trips occur automatically for each parameter and the
SLs. The reviewer should confirm that the LSSSs and LCOs, as they relate to the
reactor coolant system, do not permit operation with any expected combination of
parameters that would not satisfy the acceptance criteria.
NUREG-1537,PARr2 22 REV 0,2/96
NUREG- 1537, PART 2 22 REV 0, 2/9