NUREG-1537, Part 2 - NRC

CHAPTER 4
For a pulsing reactor, limits on pulse sizes and transient rod characteristics
should ensure that fuel is not damaged by pulsed operations. These limits
should be based on the thermal-hydraulic analyses and appear in the
technical specifications. Changes in fuel characteristics from steady power
operation that affect pulsed operation should be taken into account. Such
factors as hydrogen migration, oxidation of cladding, and decrease in
burnable poison should be addressed, if applicable.
Review Procedures
The reviewer should confirm that the thermal-hydraulic analyses for the reactor are
complete and address all issues that affect key parameters (e.g., flow, temperature,
pressure, power density, and peaking). The basic approach is an audit of the SAR
analyses, but the reviewer may perform independent calculations to confirm SAR
results or methods.
Evaluation Findngs
This section of the SAR. should contain sufficient information to support the
following types of conclusions, which will appear in the staff's safety evaluation
report:
* The information in the SAR includes the thermal-hydraulic analyses for the
reactor. The applicant has justified the assumptions and methods and
validated their results.
* All necessary information on the primary coolant hydraulics and thermal
conditions of the fuel are specific for this reactor The analyses give the
limiting conditions of these features that ensure fuel integrity.
* Safety limits and limiting safety system settings are derived from the
thermal-hydraulic analyses. The values have been justified and appear in
the technical specifications. The thermal-hydraulic analyses on which these
parameters are based ensure that overheating during any operation or
credible event will not cause loss of fuel integrity and unacceptable
radiological risk to the health and safety of the public.
NUREG-1S37,PART2
4-28
REV 0.2/96
NUREG- 1537, PRT 2 4-28 REV 0, 2/96
- U-