Document: NUREG-0800
Document ID: eb0ea00d-43e4-45d1-8a5e-4daa4263d2cf
Document Type: srp
Title: EMERGENCY CORE COOLING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550068.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.3
CFR Part: 
CFR Title: 

Content:
is applicable because the ECCS is relied upon to provide sufficient emergency core cooling flow to protect the integrity of the reactor core during postulated accidents, including the loss-of-coolant accident. Regulatory Guide 1.29 provides guidance for determining which SSCs should be designed to withstand the safe shutdown earthquake (SSE). Position C.2 recommends that SSCs whose continued function is not required but whose failure could reduce the functioning of the ECCS to an unacceptable safety level should be designed and constructed to withstand the SSE. Meeting the requirements of GDC 2, and positions of Regulatory Guide 1.29, provides assurance that plant safety is enhanced by ensuring the integrity of Seismic Category I portions of the ECCS and thus the capability to provide core cooling following a seismic event. 2. Compliance with GDC 4 requires that SSCs important to safety be designed to accommodate the effects of and be compatible with the environmental conditions associated with normal operation, maintenance, testing and postulated accident conditions. These conditions include consideration of the dynamic effects of flow instabilities and the loadings caused by water hammer events. GDC 4 is applicable because the ECCS provides emergency core cooling in the event that normal cooling methods are not available or are insufficient. Meeting the requirements of GDC 4 provides assurance that dynamic effects of events such as flow instabilities and water hammer will not adversely affect the fundamental integrity and capability of the ECCS systems to provide core cooling in the event of accidents. 3. Compliance with GDC 5 prohibits the sharing of SSCs among nuclear power units unless it can be shown that such sharing will not significantly impair the ability of the SSCs to perform their safety functions, including, in the event of an accident in one unit, and orderly shutdown and cooldown of the remaining units. GDC 5 is applicable because the ECCS provides