Document: NUREG-0800
Document ID: 02fef38f-79ed-4d55-825f-81551bcfdcdc
Document Type: srp
Title: LOSS-OF-COOLANT ACCIDENTS RESULTING FROM SPECTRUM OF
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550016.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.5
CFR Part: 
CFR Title: 

Content:
mp including requirements for reactor coolant pump trip during small break LOCAs as required by Generic Letters 85-012, 86-005, and 86-006. G. The analysis of boric acid precipitation should include a justified mixing volume which is computed as a function of time as ECC injection enters the core region. Since the size of the mixing volume is controlled by the external loop resistance and the balance of hydrostatic heads between the downcomer and inner vessel regions containing voids, the model must account for these effects. The precipitation limit must also be justified in the evaluation model. If the system design includes high concentrate boric acid tanks and/or sources, then these systems must be assumed to be operating at the time of the break initiation. H. The containment pressure response used during the ECCS performance evaluation reflects a conservatively low minimum containment pressure. I. Debris wash-down into the containment sump has been adequately treated so as to result in a conservative recirculation flow rate after switch over from the reactor water storage supply to the containment sump. J. The containment analysis should be reviewed to determine that adequate NPSH is available to support the low head pumps at the time of switch over from the reactor water storage supply to the containment sump. 6. Reactor protection system actions and safety injection actuation and delivery are consistent with the set points and the associated uncertainties and delay times listed in the SAR (OL, COL, or standard design certification review). The ECCS flow rates should be checked against the applicant's data on head-flow characteristics of the ECCS pumps given in SRP Section 6.3 and against typical safety injection tank discharge curves used for the analysis. The Regional Offices may be requested to provide data of this type from the startup tests for new designs and from periodic tests on duplicate designs. In the case of new reactor designs that use passive