ML20206S585

Responds to NRC Re Violations Noted in Insp Rept 50-155/86-07.Corrective Actions:Precaution Added to CRD Exercise Test Procedures to Highlight Potential for Stuck Selector Valves & Monitor Movement During Test

ML20206S585
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	08/18/1986
From:	Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 8609220274
Download: ML20206S585 (3)

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Kenneth W Beny Ikensusg General Offees: 1945 West Pernell flood, Jackson MI 49201 e (517) 788-1636 August 18, 1986 James G Keppler, Administrator Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

RESPONSE TO IE INSPECTION REPORT 86-07 One item of violation was identified in Inspection Rerport 50-155/86-007 dated July 18, 1986. The following is our response to that item:

Item of Violation 86-007-01 Technical Specification 7.3.4, Normal Power Operation, states that the principal functions of operators during power operation includes "the adjustment of the control rod pattern to accommodate changes in reactivity and to maintain the desired power distribution" and "the evaluation of abnormal conditions and the initiation of corrective action as required".

Technical Specification 5.2.2.f. Abnormal Behavior of the Control Rod System, requires "an immediate and thorough investigation shall be made of the occurrence of any abnormal behavior. . . of the control system to determine the cause and safety significance of the occurrence".

Contrary to the above on February 3, 1986, operators failed to investigate the cause of abnormal control rod behavior during required rod drive surveillance.

As a result, desired rod position and power distribution was not maintained.

This is a Severity Level IV violation (Supplement I).

Discussion of February 3 Event Once a week Operations perform a Control Rod Drive Exercise Test as described in Technical Specification 5.2.2.(d). During this test on February 2, 1986, operators discovered E-4 selector valve to be " sticky" and promptly lubricated and exercised E-4. Havirg decided operation of the valve had returned to OC0886-0135-NLO4 274 860818 AW z 0 m O8609gOCK050001 PDR 55 PDR _ U0f th

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J G Keppler, Administrator 2 Big Rock Point Plant Response to IEIR 86-007 August 18, 1986 normal, they returned E-4 to service. On February 3,1986, during performance of the daily exercise test, " sluggish" movement of the drives was experienced.

Operators investigated potential problem areas (ie, drive pressures, filters, screens) and continued testing. Subsequently, it was discovered that E-4 selector valve was still stuck open when picoammeters responded to a power level reduction after E-4 had inserted 12 notches. Operators did not detect movement of E-4 due to its position indication on the control rod drive matrix being away (lower right corner) from where the operator started to perform his daily exercises.

At that point, operators returned E-4 to its intended position and initiated maintenance on the E-4 selector valve.

Corrective Actions Taken Big Rock Point operators currently perform a monthly selector valve reduced pressure test as a predictive maintenance tool to icentify " sticky" selector valves and permit prompt repairs in addition to daily and weekly exercise tests. It is apparent that the weakness involved in this event was inadequate follow-up testing to insure that the lubrication and exercise efforts on February 2, 1986 were positively successful to permit return to service.

Current testing practices appear adequate to detect degraded selector valve performance.

As a result of the event, a letter was written to all operations personnel (03/12/86) describing the incident above and emphasizing the need to perform follow-up checks / testing after maintenance to insure that repair activities are successful and the component (s) are able to perform their functions properly. The letter also pointed out a need for increased attentiveness to abnormal behavior to allow investigation and correction of suspected problams.

The event was also reviewed with operators during their requalification program.

Proposed Corrective Actions to Prevent Recurrence

1. Precautions will be added to CRD exercise test procedures to highlight the potential of stuck selector valves and the need to monitor the movement of other drives during the test.

2. Instructicns will be provided to plant operators to manipulate. the reactivity switch with no drives selected and verify that no CRD covement occurs prior to performing drive exercise tests. This will permit detection of stuck selector valves prior to performance of the individual drive checks.

3. A preventative maintenance program will be developed for the selector valves. Consideration will be given to include lubrication along with an inspection for corrosion, binding, leaks, and proper operation.

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J G Keppler, Administrator 3 Big Rock Point Plant Response to IEIR 86-007 August 18, 1986 Procedure Changes will be initiated by September 15, 1986 and the Preventative Maintenance activities in place following start-up from the next refueling outage.

fd w Kenneth W Berry Director, Nuclear Licensing CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement NRC Resident Inspector - Big Rock Point i

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