Document: NUREG-0800
Document ID: f673d9c7-5410-4f11-8c45-1935b546a77f
Document Type: srp
Title: EMERGENCY DIESEL ENGINE COOLING WATER SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070570.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.5.5
CFR Part: 
CFR Title: 

Content:
pressure boundary, to safely shutdown the reactor and maintain it in a safe shutdown condition, and to prevent or mitigate the consequences of accidents. Compliance with the requirements of GDC 2 and Regulatory Guide 1.117 ensures that emergency ac power will be available to safety-related components in the event of a loss of offsite power resulting from natural phenomena events. 2. GDC 4 requires that SSC important to safety be designed to withstand the dynamic effects of pipe ruptures such as pipe whip and jet impingement, and externally or internally generated missiles. Regulatory Guide 1.115, Position C.1, identifies those essential systems that should be protected against low- trajectory turbine missiles. The safety function of the EDECWS is to provide cooling water to the EDE following an engine start signal. In order to ensure the availability of emergency ac power, the EDECWS must be capable of supplying cooling water to the engine under the expected operational and postulated accident conditions for the plant. These conditions include consideration of the dynamic effects of equipment failures such as pipe ruptures and turbine missiles, and events and conditions external to the plant. Compliance with GDC 4 and the applicable portion of Regulatory Guide 1.115 provides assurance that the dynamic effects of equipment failures, and events external to the plant, will not affect the capability of the EDECWS to provide cooling water to the emergency diesel engines. 3. GDC 5 prohibits the sharing of SSC important to safety among nuclear power units unless it can be demonstrated that such sharing will not significantly impair their ability to perform their safety functions, including in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining unit. The safety function of the EDECWS is to provide cooling water to the EDE following an engine start signal. In order to ensure the availability of emergency ac power to safety-related