Document: NUREG-0800
Document ID: 080f80e5-ae24-4b03-bcdf-a2bdfc747da6
Document Type: srp
Title: Revision 3 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070790015.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4
CFR Part: 
CFR Title: 

Content:
lear Regulatory Commission, Washington, DC 20555, Attention: Reproduction and Distribution Services Section, or by fax to (301) 415-2289; or by email to DISTRIBUTION@nrc.gov. Electronic copies of this section are available through the NRC's public Web site at http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0800/, or in the NRC's Agencywide Documents Access and Management System (ADAMS), at http://www.nrc.gov/reading-rm/adams.html, under Accession # ML070790015. NUREG-0800 U.S. NUCLEAR REGULATORY COMMISSION STANDARD REVIEW PLAN BRANCH TECHNICAL POSITION 4-1 WESTINGHOUSE CONSTANT AXIAL OFFSET CONTROL (CAOC) REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of the assessment of reactor physics, neutronics, and nuclear design Secondary - None A. BACKGROUND In connection with the staff review of WCAP-8185 (17 × 17), the staff reviewed and accepted a scheme developed by Westinghouse for operating reactors that assures that throughout the core cycle, including during the most limiting power maneuvers the total peaking factor, FQ, will not exceed the value consistent with the LOCA or other limiting accident analysis. This operating scheme, called constant axial offset control (CAOC), involves maintaining the axial flux difference within a narrow tolerance band around a burnup-dependent target in an attempt to minimize the variation of the axial distribution of xenon during plant maneuvers. Originally (early 1974), the maximum allowable FQ (for LOCA) was 2.5 or greater. Later (late 1974), when needed changes were made to the emergency core cooling system (ECCS) evaluation model, Westinghouse, in order to meet physics analysis commitments to all its customers at virtually the same time, did a generic analysis (one designed to suit a spectrum of BTP 4-1-2 Revision 3 - March 2007 operating and soon-to-be-operating reactors) and showed that most plants could meet the requirements of 10 CFR 50 Appendix K and 10 CFR 50.46 (i.e., 1204EC