ML24057A419
| ML24057A419 | |
| Person / Time | |
|---|---|
| Issue date: | 06/09/1988 |
| From: | NRC/NRR/DRO/IRIB |
| To: | |
| References | |
| CN 88-006 | |
| Download: ML24057A419 (1) | |
Text
Issue Date: 06/09/88 9900 STS 3/4.6.4 NRC INSPECTION MANUAL OTSB PART 9900: TECHNICAL GUIDANCE STS3464.TG STANDARD TECHNICAL SPECIFICATIONS SECTION 3/4.6.4 CONTAINMENT AND DRYWELL ISOLATION VALVES A.
PURPOSE To provide guidance on the interpretation of OPERABILITY as it relates to containment and drywell isolation valves (PWRs and BWRs).
B.
BACKGROUND A Project Manager requested an NRR position on a licensee's internal "position statement" on the meaning of OPERABILITY as applied to containment isolation valves. The Technical Specifications Branch believes that the misinterpretation of OPERABILITY can have safety significance in some plant-specific situations and that this misinterpretation may have been made by other licensees.
C.
DISCUSSION The licensee maintains a written Technical Specifications (TS) position statement which says, concerning the isolation valves covered by TS 3.6.4, "If the valve is closed, then the valve is operable." This position statement is wrong, because it is contrary to the definition of OPERABILITY in plant TS and because it is contrary to the Action Statements in TS 3.6.4. Also, it has safety significance because it can lead to unsafe conditions. As an example, if an inoperable isolation valve is inadvertently opened, it may not close when automatic isolation is needed. As another example, an inoperable isolation valve may be a "dual function valve" which must be able to open to allow operation of another system such as an emergency core cooling system. The NRC position is that an inoperable valve should be declared inoperable and licensees should comply with applicable Action Statements.
D.
REFERENCE The guidance provided in this directive was extracted from a memorandum from Edward J. Butcher, Chief, Technical Specifications Branch, NRR, to Project Managers, dated April 15, 1988,
Subject:
9900 STS 3/4.6.4 Issue Date: 06/09/88 Misinterpretation of Operability. The memorandum is available in the Document Control System (DCS 69316/324).
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