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:
functional and operational characteristics of the reactor protective and ECCS systems in terms of how they affect the sequence of events, and operator actions required to mitigate the consequences of the accident. The calculational framework used for the evaluation of the ECCS system in terms of core behavior is called an evaluation model. It includes one or more computer programs, the mathematical models used, the assumptions and correla- tions included in the program, the procedure for selecting and treating the program input and output information, the specification of those portions of the analysis not included in computer programs, the values of parameters, and all other information necessary to specify the calculational procedure. The evaluation model used by the applicant must comply with the acceptance criteria for ECCS given in 10 CFR Part 50, §50.46 and Appendix K to 10 CFR Part 50. The evaluation model must have been previously documented and reviewed and approved by the staff. Should the LOCA blowdown calculations be modified for the purpose of studying structural behavior (for example, core support structure design, control rod guide structure design, steam generator design, reactor coolant system piping and support structure design), all differences should be identi- fied and described by the applicant. RSB reviews these modifications, including analytical techniques, computer programs, values of input parameters, break size, type, and location, and all other pertinent information, and makes recommendations regarding their acceptability to other branches as required. RSB initiates a generic computer program review as required. RSB is also responsible for the review of the failure mode analysis of the ECCS in conjunction with the effort described in SRP Section 6.3. The RSB reviews the analytical techniques and computer programs used by the applicant for the blowdown, refill, and reflood portions of the loss-of-coolant transient. The RSB also reviews