Document: NUREG-0800
Document ID: 12f45e44-74bc-4a6b-933a-2fd6bc43c6dd
Document Type: srp
Title: deals with the fuel oil storage and transfer system for these diesel engines up to the engine
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070569.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.5.4
CFR Part: 
CFR Title: 

Content:
urposes of coping with a station blackout, provided it meets the applicable criteria for an AAC source. For a plant relying on an emergency diesel engine as an AAC power source, the design of the fuel oil storage and transfer system for that engine is acceptable if it meets 10 CFR Part 50.63, "Loss of All Alternating Current Power", paragraph (a)(2), and Regulatory Guide 1.155, Position C.3.40 Technical Rationale:41 The Technical Rationale for application of the above acceptance criteria to the EDEFSS is discussed in the following paragraphs. 1. GDC 2 requires that structures, systems, and components important to safety be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform the safety function. Regulatory Guide 1.117 provides the methods acceptable to the staff for tornado design classification of structures, systems and components important to safety. Position 13 of the appendix to Regulatory Guide 1.117 identifies Class 1E electrical systems that must be protected from the effects of tornadoes. The safety function of the EDEFSS is to store a quality fuel supply for the EDE, and transfer the fuel to the emergency diesel engine following an engine start signal. A reliable and quality fuel supply to the emergency diesel engine is necessary to ensure the prompt restoration of ac power to safety related components that are necessary to maintain the integrity of the reactor coolant 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 in relevant part requires that structures, systems, and components important to safety be