ML20063A373

Documents Basis for Request from Wisconsin Electric Power Co for Enforcement Discretion to Allow Sufficient Time to Return EDG G01 or G02 to Fully Operable Condition & If Action Not Successful to Allow for Orderly Shutdown

ML20063A373
Person / Time
Site:	Point Beach
Issue date:	12/03/1993
From:	Link B WISCONSIN ELECTRIC POWER CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
CON-NRC-93-130 VPNPD-93-205, NUDOCS 9401250263
Download: ML20063A373 (6)

Text

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• R Electnc POWER COMPANY 231 W Michgan. PO Box 2046 MJwaukee WI 53201 2046 (414)221-2345 VPNPD-93-205 NRC-93-130 PRIORITY ROUTING

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Mr. John Martin Regional Administrator gg7 '

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U.S. NUCLEAR REGULATORY COMMISSION, REGION III M-b f._

799 Roosevelt Road I f .

Glen Ellyn, IL 60137 ~

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Dear Mr. Martin:

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DOCKETS 50-266 AND 50-301 '

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dh BEOUEST FOR ENFORCEMENT DISCRETION LIMITING CONDITIOjiS FOR OPERATION y[ *

,/ f i EOINT BEACH NUCLEAR PLANT UNITSI1 AND 2 -

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The purpose of this letter is to document the bas s-.for-a request from Wisconsin Electric Power Company, licensee for Point Beach Nuclear Plant, for enforcement discretion. This request for enforcement discretion is made pursuant to the guidelines of Section VIII of the enforcement policy (10 CFR Part 2, Appendix C),

as modified in the March 17, 1993, f_ederal Recrister Notice (58 FR 14308).

REOUIREMENT FOR WHICH ENFORCEMENT DISCRETION IS REOUESTED The Limiting Condition for Operation (LCO) defined by PBNP Technical Specification Section 15.3.7, " Auxiliary Electrical Systems," Specification B.1.g allows one emergency diesel generator (EDG) to be inoperable for a period not to exceed 7 days provided the other EDG is tested daily to ensure operability and the engineered safety features associated with the EDG are operable.

The failure of the operable EDG places both PBNP units into Technical Specification Section 15.3.0, " General Considerations,"

Specification A, which requires the operating units to be placed into hot shutdown within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. Enforcement Discretion is requested to allow sufficient time to return EDG G01 or G02 to a fully operable condition and should this action not be successful, to allow time for the orderly and sequential shutdown of both units.

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Mr. John Martin December 3, 1993 Page 2 l

l CIRCUMSTANCES SURROUNDING THE SITUATION On November 29, 1993, at 0401 hours0.00464 days <br />0.111 hours <br />6.630291e-4 weeks <br />1.525805e-4 months <br /> CST, EDG G01, the Train A EDG, was voluntarily removed from service for turbocharger and idler stubshaft assembly replacement. This required placing both PBNP units into the LCO defined in Specification 15.3.7.B.1.g.

On December 2, 1993, at 2256 hours0.0261 days <br />0.627 hours <br />0.00373 weeks <br />8.58408e-4 months <br /> CST, EDG G02 was declared inoperable due to a potential problem in one of the redundant starting circuits. The declaration of G02 inoperability requires that both units be placed in hot shutdown within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> (by 0156 on December 3, 1993) as required by Specification 15.3.0.A.

On December 2, 1993, at 1920 hours0.0222 days <br />0.533 hours <br />0.00317 weeks <br />7.3056e-4 months <br /> CST, the control room received an EDG G02 annunciation on Main Control Board CO2. A check of the local alarms revealed that the fuel pressure alarm was in and the electric fuel oil pump was running. Additional engineering and maintenance personnel were called in to troubleshoot the alarm. At 2256 hours0.0261 days <br />0.627 hours <br />0.00373 weeks <br />8.58408e-4 months <br />, troubleshooting determined that the start lockout relay ~

contact on the #2 start circuit (STLO-2) was energized which disabled the #2 start circuit causing the electric fuel oil pump to run. At this time, EDG G02 was declared inoperable and a 7-day-LCO for that machine was entered in accordance with Specification 15.3.7.B.1.g. This resulted in both EDGs being inoperable and invoking the requirements of Specification 15.3.0.A. At 2315 hours0.0268 days <br />0.643 hours <br />0.00383 weeks <br />8.808575e-4 months <br /> CST, it was determined that mechanical binding of an engine stop (ESTR) relay which energizes the STLO-2 relay, or sluggish operation of the STLO-2 relay, was the probable cause of the alarm.

During troubleshooting, this problem could not be duplicated.

Repeated operation of the ESTR and STLO-2 relays indicated no mechanical binding.

The NRC Senior Resident Inspector was notified of the event at 2305 hours0.0267 days <br />0.64 hours <br />0.00381 weeks <br />8.770525e-4 months <br />, with an ENS notification being submitted to the NRC Operations Center at 2353 hours0.0272 days <br />0.654 hours <br />0.00389 weeks <br />8.953165e-4 months <br /> CST. On December 3, 1993, at 0057 hours6.597222e-4 days <br />0.0158 hours <br />9.424603e-5 weeks <br />2.16885e-5 months <br /> CST, a load reduction of 15%/ hour on both of the units commenced in accordance with TS 15.3.0.A. At 0137 hours0.00159 days <br />0.0381 hours <br />2.265212e-4 weeks <br />5.21285e-5 months <br /> CST, the power reduction was suspended with the approval of NRC Region III personnel.

Troubleshooting of the G02 relay was. continued and it was decided that an accelerated schedule for returning EDG G01 to service would ,

be implemented. A quorum of the Manager's Supervisory Staff was '

convened at the plant at 0030 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

l An accelerated work plan was implemented for the return of EDG G01 3' to service. It was decided that the test for proper phase rotation of the G01 generator output contained in the original work plan I

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n Mr. John Martin December 3, 1993 Page 3 could be eliminated as the configuration and orientation of the leads, combined with the experience of the craft personnel involved in the work and the quality control implemented, minimized the possibility of incorrectly realigning the leads. At 0040 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> CST,. the return to service test of Gol commenced, with an estimated completion time of 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br /> CST. This time included a required run at 2500 kW plus a run at 3050 kW to test the new turbocharger unit, as well as allotting time for analysis of test results. '

Correct phase rotation was demonstrated by the ability to synchronize and place G01 on the energized buses. The initial load test of the machine at 2500 kW was completed at 0205 hours0.00237 days <br />0.0569 hours <br />3.38955e-4 weeks <br />7.80025e-5 months <br /> CST.

The return to service and load test was completed and results were accepted at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br /> CST. EDG G01 was declared operable at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br /> CST and the extended 3-hour LCO on both units as well as the 7-day LCO on G01 was exited. At 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br /> CST, a load increase on both units was initiated. Both PBNP units achieved full load'at 0320 hours0.0037 days <br />0.0889 hours <br />5.291005e-4 weeks <br />1.2176e-4 months <br />.

At 0125 hours0.00145 days <br />0.0347 hours <br />2.066799e-4 weeks <br />4.75625e-5 months <br />, a presentation regarding the status of G02 was made to the Manager's Supervisory Staff. While it was decided that G02 would not be tested during the return to service testing of G01, the staff considered that the immediate cause of EDG alarm was known. Attempts to replicate the failure during troubleshooting were not successful. Accordingly, it was the decision of the MSS that G02 was available, but not to be considered operable, until the machine could be tested following satisfactory completion of testing and return to service of G01.

Following return of EDG G01 to service, surveillance testing of EDG G02 commenced. Testing was completed and results were accepted by Operations at 0451 hours0.00522 days <br />0.125 hours <br />7.457011e-4 weeks <br />1.716055e-4 months <br /> CST. Both the STLO-2 and ESTR relays were observed to have actuated properly during this testing. It was decided, however, that EDG G02 would be considered to be available, but not operable, pending further engineering evaluation on December 3, 1993. Accordingly, EDG G02 remains in the 7-day LCO which was entered at 2256 hours0.0261 days <br />0.627 hours <br />0.00373 weeks <br />8.58408e-4 months <br /> CST on December 2, 1993.

COMPENSATORY ACTIONS Prior to removing EDG G01 from service, the onsite combustion turbine generator (G05) was tested on November 28, 1993, at 1831 hours0.0212 days <br />0.509 hours <br />0.00303 weeks <br />6.966955e-4 months <br /> to ensure its operability. G05 can be used to supply power to both the Train A and Train B safeguards buses should a loss of offsite power occur during the duration of the enforcement discretion. No work is or has been performed since the test on November 28, 1993, which affects the operability of G05.

Mr. John Martin December 3, 1993 Page 4 We requested special consideration from our system control center to minimize requests for changes to the loading of the PBNP units, as well as to minimize any foreseeable perturbations on the 345 kV grid. All four 345 kV lines to PBNP are operable.

Although G02 was not declared operable, it was maintained in an available status to receive and respond to an automatic start signal. All indications were that G02 would respond to an automatic start signal and function as designed. Troubleshooting or work that would render G02 incapable of responding was suspended until G01 was returned to service.

SAFETY SIGNIFICANCE AND POTENTIAL CONSEOUENCES Continued operation of both units for the duration of this enforcement discretion in excess of the 3-hour action time required by Specification 15.3.0.A will not result in an increased risk to the health and safety of the public and plant personnel.

The shutdown of both units within the 3-hour action time limit of i Specification 15.3.0 places the units through simultaneous l transients, placing unnecessary burden on the operating crew, and therefore increases the probability of initiating an event which would challenge the engineered safety features of the reactor protection system. Sequential shutdown of the units allows normal and orderly shutdown of each unit, minimizes the effects of the shutdown transients on the units and the burden on the operating crew.

During the time that both units are operating at power, should a loss of offsite power occur, resulting in a station blackout,_the combustion turbine (G05) is operable and available to provide power to the required safe shutdown loads. In addition, both units will be near normal operating temperatures which allows use of the steam generators and auxiliary feedwater system for the removal of decay heat. If the units are in cold shutdown, a loss of decay heat removal capability would occur until the required shutdown loads.

are repowered from G05.

JUSTIFICATION FOR THE DURATION OF THE ENFORCEMENT DISCRETION We requested an LCO extension for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, to 0556 hours0.00644 days <br />0.154 hours <br />9.193122e-4 weeks <br />2.11558e-4 months <br /> CST on December 3, 1993, prior to continuing the shutdown of the two units. An additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> was requested-to sequentially shut-down each unit. This time is sufficient to allow completion of G01 repairs and return to service testing, and to allow an orderly and sequential shutdown of both PBNP units using normal shutdown procedures (15%/ hour) should these repairs not be successful.

v Hr. John Martin December 3, 1993 Page 5 l

l ENVIRONMENTAL CONSEOUENCES We have determined that operation in this condition does not involve a significant hazards consideration, authorize a significant change in the types or total amounts of any effluent release, or result in any significant increase in individual or  ;

cumulative occupational radiation exposure. Therefore, we conclude  !

that this request meets the categorical exclusion requirements of j 10 CFR 51. 22 (c) (9) and that an environmental impact statement or ,

negative declaration and environmental impact appraisal need not be )

prepared. '

STATE NOTIFICATION STATEMENT  :

We will notify the Public Service Commission of Wisconsin and the i appropriate State of Wisconsin officials of the requested enforcement discretion by copy of this letter in accordance with 10 CFR 50.91(b).

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SUMMARY

OF COMMUNICATIONS AND APPROVALS The PBNP Manager's Supervisory Staff (onsite nuclear safety review committee) convened and discussed this issue at 0100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> on December 3, 1993, concurred with the decision to request this enforcement discretion, and concurred with the content of this  !

request. H l

A telephone conference between the Nuclear Reactor Regulation (NRR) j offices, NRC Region III, PBNP, and WE corporate offices was I I

initiated and 0135 CST on December 3, 1993, to discuss this request for enforcement discretion.

At the beginning of our conference with NRC representatives, it was pointed out by the Manager-PBNP that as of 0135 hours0.00156 days <br />0.0375 hours <br />2.232143e-4 weeks <br />5.13675e-5 months <br /> CST, rampdown of both PBNP units was in progress at a rate of 15%/ hour in accordance with normal shutdown procedures. Units 1 and 2 were currently being at 92% and 89% power respectively, and only approximately 20 minutes of the three-hour LCO remained prior to the units being required to be in the hot shutdown condition.

Accordingly, it was requested that the requirements of the LCO be suspended for the duration of the telephone conference. This request was verbally approved by your regional representatives at 0137 hours0.00159 days <br />0.0381 hours <br />2.265212e-4 weeks <br />5.21285e-5 months <br /> CST.

Verbal approval of this enforcement discretion was granted at 0225 hours0.0026 days <br />0.0625 hours <br />3.720238e-4 weeks <br />8.56125e-5 months <br /> by Mr. Ed Greenman to permit extension of the 3-hour Specification 15.3.0 to 0556 hours0.00644 days <br />0.154 hours <br />9.193122e-4 weeks <br />2.11558e-4 months <br /> CST, at which time the orderly sequential rampdown of the units would be initiated if an EDG had

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!~ M John Martin December 3, 1993 Page 6 not been restored to operable status. It was further decided that should an EDG not be restored to operable status, a telephone conference would be held at 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br /> CST to review the status of corrective actions and considerations relative to the shutdown of the units.

An update regarding this event was made to the NRC Operations Center on December 3, 1993, at 0342 hours0.00396 days <br />0.095 hours <br />5.654762e-4 weeks <br />1.30131e-4 months <br />. The Public Service Commission of Wisconsin will be provided a copy of this request.

If you have any questions or require additional information, please contact us.

Sincerely, d,. '~

Bob Link Vice President Nuclear Power TGM/jg '

cc: NRC Resident Inspector NRC Document Control Desk PSCW l

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