Document: NUREG-0800
Document ID: a41f4aae-e975-45f3-aebc-5519bec72c6e
Document Type: srp
Title: CRITICALITY SAFETY OF FRESH AND SPENT FUEL STORAGE AND HANDLING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070570006.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.1.1
CFR Part: 
CFR Title: 

Content:
derator. C. For boiling-water reactor pools or for pressurized-water reactor (PWR) pools where no credit for soluble boron is taken, criticality information (including associated assumptions and input parameters) in the SAR must show that the spacing between fuel assemblies in the spent fuel storage racks is sufficient to maintain the array such that, when fully loaded and flooded with full-density unborated water, the K(eff) will not exceed 0.95 for all normal and credible abnormal conditions. Credit may be taken for neutron-absorbing materials. The K(eff) must include allowance for all relevant uncertainties and tolerances. D. For PWR pools where partial credit for soluble boron is taken, both of the following criteria must be met: i. When the spent fuel storage racks are loaded with fuel of the maximum permissible reactivity and are flooded with full-density unborated water, the maximum K(eff) must be less than 1.0 for all normal and credible abnormal conditions. The K(eff) must include allowance for all relevant uncertainties and tolerances. ii. When the spent fuel storage racks are loaded with fuel of the maximum permissible reactivity and are flooded with full-density water borated to a minimum concentration (CB,min, measured in parts per million of boron), the maximum K(eff) must be no greater than 0.95 for all normal conditions. Plant technical specifications must incorporate the CB,min. The K(eff) must include allowance for all relevant uncertainties and tolerances. In evaluation of these criteria, credit may be taken for neutron-absorbing materials other than soluble boron. 9.1.1-6 Revision 3 - March 2007 Reliance on soluble boron credit should be minimized. Use of soluble boron credit removes defense in depth credited explicitly or implicitly elsewhere in the criticality analyses. E. When credit is taken for neutron absorbing material, its compatibility and chemical stability in the components wetted by water in the spent fuel pool and in the new fuel