Document: NUREG-0800
Document ID: e1169529-d2cb-4947-9efe-b23d927f4aa9
Document Type: srp
Title: NUREG40800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350520.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8
CFR Part: 
CFR Title: 

Content:
2 Rev. 2 - July 1981 BRANCH TECHNICAL POSITION 2 (PSB) DIESEL-GENERATOR RELIABILITY QUALIFICATION TESTING (BTP ICSB-2 (PSB) HAS BEEN SUPERCEEDED BY IEEE-387) I 8A-3 Rev. 2 - July 1981 BRANCH TECHNICAL POSITION ICSB-4 (PSB) REQUIREMENTS ON MOTOR-OPERATED VALVES IN THE ECCS ACCUMULATOR LINES A. BACKGROUND For many postulated loss-of-coolant accidents, the performance of the emergency core cooling system (ECCS) in pressurized water reactor plants depends upon proper functioning of the safety Injection tanks (also referred to as "accumula- tors" or "flooding tanks" in some applications). In these plants, a motor- operated isolation valve (tOIV) and two check valves are provided in series between each safety Injection tank and the reactor coolant (primary) system. The MOIVs must be considered to be "operating bypasses" because, when closed they prevent the safety injection tank from performing the Intended protective function. IEEE Std 279 has a requirement for "operating bypasses" which states that the bypasses of a protective function will be removed automatically whenever permissive conditions are not met. This Branch Technical Position provides specific guidance in meeting the intent of IEEE Std 279 for safety injection tank MOIVs. It should be noted that BTP ICSB 18 (PSB), UApplication of the Single Failure Criterion to Manually-Controlled Electrically-Operated Valves," also applies to these isolation valves and should be used in conjunction with this position. B. BRANCH TECHNICAL POSITION The following features should be incorporated in the design of DOIV systems for safety injection tanks to meet the intent of IEEE Std 279: 1. Automatic opening of the valves when either primary coolant system pressure exceeds a preselected value (to be specified in the technical specifications), or a safety injection signal is present. Both primary coolant system pressure and safety injection signals should be provided to the valve operator. 2. Visual indication in the control