Document: NUREG-0800
Document ID: 7e9d3620-7a94-488e-b2d5-992282113080
Document Type: srp
Title: NUREG408OO
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350480.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
" 2. IEEE Std 279, "Criteria for Protection Systems for Nuclear Power Generating Stations." 7A-16 Rev. 2 - July 1981 BRANCH TECHNICAL POSITION ICSB 25 GUIDANCE FOR THE INTERPRETATION OF GENERAL.DESIGN CRITERION. 37 FOR TESTING THE - OPERABILITY.-OF THE EMERGENCY CORE COOLING SYSTEM AS A WHOLE [BTP has been superseded by Standard Technical SpecificationsJ I 7A-17 Rev. 2 - July 1981 -BRANCH TECHNICAL POSITION ICSB 26 REQUIREMENTS FOR REACTOR PROTECTION SYSTEM ANTICIPATORY TRIPS A. BACKGROUND Several reactor designs have incorporated a number of anticipatory or "back-up" trips for which no 'credit was taken in the accident analyses. These trips, as a rule, were not designed to the requirements of IEEE Std 279 and therefore introduced nonsafety grade equipment into the reactor protection system. It was determined by the staff that this was not an acceptable practice, because of possible degradation of the reactor protection system. B. BRANCH TECHNICAL POSITION. All reactor trips incorporated in the reactor protection system should be designed to meet the requirements of IEEE Std 279. This position applies to the entire trip function from the sensor to the final actuated device. For sensors located in nonseismic areas the installation (including circuit routing) and design should be such that the effects of credible faults (i.e. grounding, shorting, application of high voltage, or electromagnetic inter- ference) or failures in these areas could not be propagated back to the RPS and degrade the RPS performance or reliability. The sensors should be qualified to operate in a seismic event, i.e., not fail to initiate a trip for conditions which would cause a trip. C. REFERENCES 1. Shearon Harris Safety Evaluation Report, September 15, 1972. 2. IEEE Std 279, "Criteria for Generating Stations." Protection Systems for Nuclear Power 3. NUREG 0718 and 0737, Items II.K.2.10* and II.K.3.12. Task Action Plan item II.K.1.21 has been superseded by item II.K.2.10. I I 7A-18 Rev. 2 -