Document: NUREG-0800
Document ID: 8940dd69-2a01-4786-bbe6-f71794a60643
Document Type: srp
Title: LOSS-OF-COOLANT ACCIDENTS RESULTING FROM SPECTRUM OF POSTULATED PIPING
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350156.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.5
CFR Part: 
CFR Title: 

Content:
culations with modified assumptions are requested); peak clad temperature as a function of break size (if it is uncertain whether the peak value has been found, additional calculations are requested); predicted "end-of-bypass" time compared to calculated downcomer flow and to staff calculations for typical plants; pump speed transients; containment pressure transients (if staff calcula- tions are not available, these are requested from CSB); and carryover fraction (if it is not an input to the calculations). 7. The calculated peak clad temperature, maximum local oxide thickness, and core average zirconium-water, reaction meet the acceptance criteria for ECCS given in 10 CFR Part 50, §50.46 and Appendix K to 10 CFR Part 50. 8. The applicant's analysis addresses the full LOCA sequence of events to the point where the plant is in the long-term cooling mode and removal of deciy heat has been well established for both large and small breaks. The reviewer checks the assumed sources of coolant water, redundancy of delivery routes, alignment of valves, control of boron concentration (PWR) and all required operator actions. 9. The following THI Action Plans (Ref. 6 and 7) items are reviewed to assure compliance with the acceptance criteria: a. II.E.2.3. The reviewer evaluates the uncertainty analyses performed by the applicant to meet item II.E.2.3 to assure that the modeling assumptions and phenomena for small-break LOCA calculations are properly accounted for to determine the acceptability of the ECCS performance pursuant to Appendix K of 10 CFR. Part 50. b. II.K.2.8. For Babcock and Wilcox designs, the reviewer confirms that the auxiliary feedwater system upgrade and automatic auxiliary feedwater initiation performed under this TMI action plan item have been properly accounted for in the LOCA analyses. 15.6.5-6 Rev. 2 - July 1981 c. II.K.3.5. The reviewer evaluates the assumptions made regarding reactor coolant pump trip to assure that they are consistent and