DCL-10-026, Technical Specification 5.6.8 PAM Instrumentation Report

Technical Specification 5.6.8 PAM Instrumentation Report

ML100890225
Person / Time
Site:	Diablo Canyon
Issue date:	03/23/2010
From:	Becker J Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-10-026
Download: ML100890225 (2)

Text

PacificGas and Electric Company- James R. Becker Diablo Canyon Power Plant Site Vice President Mail Code 104/5/601 P 0. Box 56 Avila Beach, CA 93424 805.545.3462 March 23, 2010 Internal: 691.3462 Fax: 805.545.6445 PG&E Letter No. DCL-10-026 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Diablo Canyon Unit 1 Technical Specification 5.6.8 PAM Instrumentation Report

Dear Commissioners and Staff:

Pacific Gas and Electric Company (PG&E) is submitting the enclosed report in accordance with Technical Specifications 3.3.3, Post Accident Monitoring (PAM)

Instrumentation, and 5.6.8, PAM Report, for an inoperable channel for the Diablo Canyon Power Plant (DCPP) reactor vessel water level indication system (RVLIS).

The inoperable Unit 1 RVLIS instrumentation channel is not considered risk-significant and does not adversely affect health and safety of the public.

PG&E makes no regulatory commitments as a part of this submittal.

swh/50298286/009 Enclosure cc: Elmo C. Collins, NRC Region IV Michael S. Peck, DCPP NRC Resident Alan B. Wang, NRR A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway - Comanche Peak . Diablo Canyon

• Palo Verde- San Onofre

• South Texas Project

• Wolf Creek

PG&E Letter DCL-10-026 Enclosure POST ACCIDENT INSTRUMENT4INOPERABILITY REPORT DCPP Unit 2 RVLIS Channel B Inoperability Condition / Requirement:

Diablo Canyon Power Plant (DCPP) Technical Specification (TS) 3.3.3,"Post Accident Monitoring (PAM) Instrumentation," Table 3.3.3-1, Function 6, defines the instrumentation requirements for the Reactor Vessel Water Level Indication System (RVLIS). On February 11,2010, the DCPP Unit 1 RVLIS Channel B became inoperable due to a field input, wide range temperature element failure. TS 5.6.8, PAM Report, Condition B or F of Limiting Condition for Operations (LCO) 3.3.3 states a report shall be submitted within the following 14 days when Condition A of the LCO can not be met.

The following information is submitted as required by TS 5.6.8, PAM Report:

1. The preplanned alternate method of monitoring:

Four instrumentation systems are available for monitoring and detection of inadequate core cooling. The alternate methods of monitoring are:

(1) Reactor Vessel Water Level Indication System - Channel A; (2) Subcooling margin monitors; (3) Incore (core exit) thermocouples; and (4) Pressurizer level indication

2. The cause of the inoperability:

The field connection of the circuit cable at the DCPP Unit 1, Loop 2, reactor coolant system wide range hot leg temperature element has failed. This provides input to Unit 1 RVLIS Channel B and a redundant temperature input does not exist.

3. The plans and schedule for restoring the instrumentation channels of the function to operable status.

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The plans for restoring the instrumentation channel to an operable status will require a plant shutdown and entry into 'mode 5. This repair will be made during the next planned Unit 1 refueling outage or an unplanned/forced outage of'sufficient duration.