Document: NUREG-0800
Document ID: 34798f4a-fe75-475a-b41f-ffb023158358
Document Type: srp
Title: 2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070367.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.2.15
CFR Part: 
CFR Title: 

Content:
ng or interfering with core cooling. 3. GDC 4, in relevant part, requires that SSCs important to safety be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operations, maintenance, testing, and postulated accidents, including LOCAs. The reactor internals perform and/or may affect the performance (through their failure) of safety functions including reactivity monitoring and control, core cooling, and fission product confinement. Application of GDC 4 to the reactor internals provides assurance that the effects of environmental conditions to which they are exposed over their installed life will not diminish the likelihood of performance of these safety functions under all operating conditions, including accidents. This provides assurance that failures of the reactor internals resulting from environmental service conditions that could cause loss of capability to monitor reactivity, fuel damage resulting from loss of reactivity control, structural damage to fuel cladding, or interference with core cooling are not likely to occur. NUREG-0609 identifies and evaluates certain postulated pipe ruptures (e.g. double- ended guillotine breaks of primary reactor coolant loop piping) that are known to result in asymmetric blowdown loadings on the reactor internals. GDC 4 allows such dynamic effects associated with postulated pipe ruptures to be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping. Application of GDC 4 to the reactor internals provides assurance that asymmetric loading effects associated with postulated pipe ruptures are either accommodated in the design (with assurance of the functionality and integrity of reactor internals) or demonstrated to be extremely unlikely to occur. This provides assurance that overstress