Document: NUREG-0800
Document ID: ea7ce8f5-32bf-4d8c-a653-e964bff0ef48
Document Type: srp
Title: EMERGENCY CORE COOLING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070448.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.3
CFR Part: 
CFR Title: 

Content:
abilities and the loadings caused by water hammer events. The ECCS provides emergency core cooling in the event that normal cooling methods are not available or are insufficient. Compliance with GDC 4 enhances plant safety by providing 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. 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. The ECCS provides an important safety function in its ability to provide emergency core cooling and shutdown capability following postulated accidents. The ECCS system must be designed such that the ability to perform this and other designated safety-related functions are not compromised for each DRAFT Rev. 3 - April 1996 6.3-10 unit regardless of equipment failures or other events that may occur in another unit. Meeting the requirements of GDC 5 enhances plant safety by providing assurance that unacceptable effects of equipment failures or other events occurring in one unit of a multi-unit site will not propagate to the unaffected unit(s). 4. GDC 17 requires that an on-site and off-site electric power supply system be provided to permit functioning of SSCs important to safety. As it relates to the ECCS systems, GDC 17 requires that each power supply system have sufficient capacity and capability to ensure that the core can be cooled in the event of an accident, and that the fuel design limits and the design conditions of the reactor coolant pressure boundary are not exceeded during anticipated operational occurrences (AOOs). The ECCS is dependent upon the availability of electrical power supplied from the Class IE