NUREG-1537, Part 2 - NRC

HEU TO LEU CONVERSION
should be discussed and justified here and referenced to the technical specifications
discussion.
Operating parameters that verify proper core configuration and behavior and can
be accurately measured, should be verified by measurements in the startup test
program. A range of expected values with acceptance criteria and bases should be
provided in this discussion and referenced to the startup test program discussion.
Acceptance Criteria (Sections 4.5.1-4.5.4)
Acceptance criteria for the dynamic'design should be based on the following
considerations: The comparison of the parameters for the existing HEU and.
proposed LEU cores that are significant factors in the stability and dynamic
behavior of the reactor during steady-state or pulsed operation should not
significantly change. The temperatuire coefficients and void coefficient of
reactivity of the LEU-fueled reactor should rem'ain sufficiently negative over the
allowed ranges of operation that credible reactivity additions are compensated to
prevent violation of facility design and safety limits. If the coefficients are not
negative, the licensee should justify the values and discuss compensating safety
features. If there are no major differences"in the magnitudes or funictions of
individual parameters between the IEU and LEU c'ores, the reviewer should
accept the licensees use of the same analytical and computational methods to
compare the performances of the two'reactors. The analyses should confirm that
the analytic results for the BEU core have been qualified by reasonable agreement
with the experimentally determined parameters of that core and other test cores,
such as those tested at the Special Power Excursion Reactor Test (SPERT) project
(Nyer et al., 1956). The safety significance of any differences between calculated
and measured reactor performances should be discussed and analyzed by the
licensee to demonstrate that reactor safety is ensured. The proposed conversion
should be acceptable if the analyses of the HEU and LEU cores confirm (a) no
significant decrease in safety margin for the ful range of operational conditions
and (b) no loss of fuel integrity. The proposed startup test program plan should
include verification of reactor core parameters as outlined in Section 12 that
includes comparison to the predictions in this section. 'Postulated accident
conditions should be evaluated in Section 13 ofthe SAR. -
Review Procedures (Sections 4.5.1-4.5.4)
The reviewer should evaluate all reactor parameters that affect reactor operation,
determine fuel integrity, and affect oveiall reactor safety. The'reviewer should
evaluate the methods and assumptions used by the licensee to analyze the
operations of the REU-fueled reactor. These analyses should be qualified by
comparison with experimentally determined values for the HEU core. 'The
reviewer should evaluate the licensee's analyses of the LEU core and compare
REv 0, 2/96 17 STANDARD REVIEWPLAN