HL-5278, Special Rept:On 961203,30 Days Elapsed Since Position Indication Light for MSIV 1B21-F022D Declared Inoperable. Caused by Limit Switch Out of Proper Adjustment for Power Conditions.Light Will Be Restored During Next Outage

Special Rept:On 961203,30 Days Elapsed Since Position Indication Light for MSIV 1B21-F022D Declared Inoperable. Caused by Limit Switch Out of Proper Adjustment for Power Conditions.Light Will Be Restored During Next Outage

ML20132B755
Person / Time
Site:	Hatch
Issue date:	12/11/1996
From:	Beckham J GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HL-5278, NUDOCS 9612170375
Download: ML20132B755 (3)

Text

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'Geo,rgia Power Company

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• 40 invemess Center Parkway Post Othee Box 1295 Dermingham. Alabama 35201 Telephone (205) 877-7279 J. T. Beckham, Jr.

Vice President - Nuclear GeorgiaPower O

Hatch Project a subsid:vy of December 11, 1996 The souven ampany Docket No. 50-321 HL-5278 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant - Unit 1 Post Accident Monitoring Instrumentation Report Position Indicating Light on Main Steam Isolation Valve Inocerable for Greater Than 30 Days Gentlemen:

In accordance with the requirements of Plant Hatch Unit 1 Technical Specifications 3.3.3.1, Required Action B.1, Georgia Power Company is submitting the following post accident monitoring instrumentation report regarding a failed Main Steam Isolation Valve position indicating light.

1 Please contact this office if you have any questions.

Sincerely, j n J. T. Beckham, Jr. 7 OCV/eb Enclosure cc: Georgia Power Commny Mr. H. L. Sumner, Nuclear Plant General Manager NORMS h U.S. Nuclear Regulatory Commission. Washington. D.C.

Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Regulatory Commission. Region 11 Mr. S. D. Ebneter, Regional Administrator Mr. B. L. Holbrook, Senior Resident Inspector - Hatch

.1 961217o373 961211 PDR ADOCK 05000321 S PDR ,

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Enclosure i

Edwin I. Hatch Nuclear Plant - Unit 1 Post Accident Monitoring Instrumentation Report Position Indication Light on Main Steamline Isolation Valve Inonerable for Greater than Thirty Days A. REQUIREMENT FOR REPORT This report is required by Unit 1 Technical Specifications Limiting Condition for Operation 3.3.3.1, Required Action B.l. This required action must be entered if the plant has less than the required number of operable post accident instmmentation channels for a period greater than 30 days. When 30 days have elapsed, tia required action indicates that a report be submitted to the Nuclear Regulatory Commission within the following 14 days per Unit 1 Technical Specificatior.s section 5.6.6 and 10 CFR 50.4. In this event, the position indication light for inboard main steamline isolation valve (MSIV) IB21-F022D, required by Unit 1 Technical Specifications, Table 3.3.3.1-1, item 6, was inoperable for a period greate- than 30 days.

B. DESCRIPTION OF EVENT On 12/03/96, Unit I was in the Run mode at a power level of 2558 CMWT (100 percent rated thermal power). At that time,30 days had elapsed since the position ,

indication light for MSIV IB21-F022D had been declared inoperable. It was declared inoperable because its red open indication remained illuminated even when the valve was closed.

C. CAUSE OF EVENT This event appears to be the result of a limit switch that is out of proper adjustment for power conditions. The event was discovered during the plant response to a 10 CFR 21 notification concerning solenoid-operated pneumatic valves which are used on the Unit 1 MSIVs. The solenoid valve is one of two pneumatic valves on each MSIV which control closing and opening of the MSIVs.

Since the solenoid valve problem manifests itself at the elevated temperatures experienced at power in the form oflengthened closing times on affected MSIVs, the plant tested for the presence of the problem by timing each MSIV during its closure stroke. The test required use of position indication lights to mark the completion of the close stroke. During this testing, three of the eight MSIVs required some degree of adjustment in the limit switches controlling the position lights to get the red "open" lights to extinguish when the MSIVs closed. Two of these occurred on outboard valves which are accessible during power operation.

These were adjusted and the indication problem no longer occurs. Subsequent tests using repaired position indication lights showed that the MSIVs closed in the required band of three to five seconds. However, one of the position indication

' lights needing adjustment was on 1B21-F022D which is an inboard valve (i.e.,

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. ' Enclosure Post Accident Monitoring Instrumentation Report located inside the primary containment) and thus is not accessible during power operation. Hence, the position indication light could not be adjusted so as to be l usable in testing this MSIV.

Plant operators observed the rate of decrease in steam flow on each main steamline  !

as each MSIV was closed during testing, including the line which had the MSIV with the inoperable position indication light. No difference was observed in the time required to achieve indication of zero steam flow between the lines with l operable position indication and the one line which had inoperable position indication. Based on these observations, therefore, it was concluded that the MSIV with the inoperable position indication light was actually going closed in the required time and the primary containment isolation function was operable. This l led to the further conclusion that the condition referenced in the 10 CFR 21 notification concerning the solenoid valve does not exist at Plant Hatch.

D. PLANT RESPONSE TO THIS EVENT

1. Preolanned Alternate Method: The subject position indication light has no automatic safety function and serves no purpose other than to provide operators with an indication whether the MSIV is open. The purpose of the ,

MSIV, in turn, is to shut offits respective main steam line, thereby isolating its  !

primary containment penetration. As explained above, testing of this MSIV l showed it is operable with respect to its PCIV function. However, should conditions arise requiring a Group 1 primary containment isolation, the redundant MSIV in the same penetration will provide additional assurance that the affected primary containment penetration is isolated as required. The position indication light on the outboard MSIV in this same penetration is operable. In addition, plant operators are trained to confirm proper penetration isolation by verifying closure of the redundant valve and by using other indications such as zero steam flow.

2. Schedule for Restoring Instrumentation to Operable Status: This position indicating 1:ght will be adjusted and restored to operable status during the next outage of suflicient duration. Currently this is forecasted to be the next Unit I refueling outage, scheduled to begin in October 1997 and to be completed in November 1997.

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