Document: NUREG-0800
Document ID: 92d817ac-3ce3-4cf7-8d1a-627e8242fbf2
Document Type: srp
Title: PLANT DESIGN FOR PROTECTION AGAINST POSTULATED PIPING FAILURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070312.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.1
CFR Part: 
CFR Title: 

Content:
ch longitudinal or circumferential break in high energy fluid system piping or leakage crack in moderate energy fluid system piping should be considered separately as a single postulated initial event occurring during normal plant conditions. An analysis should be made of the effects of each such event, taking into account the provisions of BTP EMEB 3-1 and of the system and component operability considerations of item B.3.b. below. The effects of each postulated piping failure should be shown to result in offsite consequences within the guidelines of 10 CFR Part 100 and to meet the provisions of items B.3.c and d below. b. In analyzing the effects of postulated piping failures, the following assumptions should be made with regard to the operability of systems and components: (1) Offsite power should be assumed to be unavailable if a trip of the turbine-generator system or reactor protection system is a direct consequence of the postulated piping failure. 3.6.1-15 DRAFT Rev. 3 - April 1996 (2) A single active component failure should be assumed in systems used to mitigate consequences of the postulated piping failure and to shut down the reactor, except as noted in item B.3.b(3) below. The single active component failure is assumed to occur in addition to the postulated piping failure and any direct consequences of the piping failure, such as unit trip and loss of offsite power. (3) Where the postulated piping failure is assumed to occur in one of two or more redundant trains of a dual-purpose moderate-energy essential system, i.e., one required to operate during normal plant conditions as well as to shut down the reactor and mitigate the consequences of the postulated piping failure, single active failures of components in the other train or trains of that system or other systems necessary to mitigate the consequences of the piping failure and shut down the reactor, need not be assumed provided the systems are designed to seismic Category I standards, are powered