ML20128E347

Confirms Granting of Temporary Waiver of Compliance for Facility from Provisions of TS Section 3.8.3.1.b.(2), LCO, for 24 H Period

ML20128E347
Person / Time
Site:	Callaway
Issue date:	12/01/1992
From:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Schnell D UNION ELECTRIC CO.
Shared Package
ML20128E353	List: ML20128E347 ML20128E364
References
NUDOCS 9212080060
Download: ML20128E347 (3)

Text

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p0 080 UNITED STATES f, . f,, NUCLEAR REGULA10RY COMMISSION

[ $ REGION 111 7, 799 ROOSEVELT RO AD O

if s sii GLEN ELLYN. ILLINOIS 60137

/

DEC 011992

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Docket No. 50-483 Mr. Donald F. Schnell Senior Vice President - Nuclear Union Electric Company Post Office Box 149 St. Louis, MO 63166 SUBJFCT: REQUEST FOR TEMPORARY F.IVER OF COMPLIANCE - TECHNICAL SPECIFICATION 3.8.3.1, ONSITE POWER DISTRIBUTION _ ,

Dear Mr. Schnell:

1 This confirms the granting of a Temporary Waiver of Compliance (TWOC) for the Callaway Plant, Unit 1, from the provisions of Technical Specification Section 3.8.3.1.b.(2), " Limiting Conditions for Operation", for a 24-hour period. Oral approval for this waiver was provided at 3:43 p.m. on November 27, 1992, during a telephone conference between our respective staffs and members of NRR. On November 27, 1992, we received your letter, enclosed, requesting the TWOC.

Callaway Plant, Unit 1, is currently in Mode 1 at 100% power. Technical  !

Specifications (TS) Section 3,8.3.1.f. requires that the 120 Volt ,

A. C. Vital Bus NN04 be energized from its associated inverter connected to D C. Bus NK04. This TS scction further states that if these requirements are not met within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the unit will be in at least Hot Star.dby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Coid Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.  !

On November 27, 1992, you orally informed the NRC that on November 26, 1992, '

at 1746 CST, inverter NN14 tripped resulting in a loss of instrument bus NN04.

The plant operators promptly transferred the NN04 protective channels to the station backup power supply XNN06 and began trouble-shooting to determine the root cause of the inverter failure. You also informed the NRC that the most probable cause of the failure of the NN14 inverter had been determined to be a faulty ferroresonant transformer and/or wave shaping capacitors which were i replaced.  !

You requested an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before the unit would be required to i comply with the Technical Specification requirement to be placed in Hot i Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. ,

This waiver was requested to permit inverter testing and restoration and to l avoid a shutdown and cooldown transient that would be imposed on the plant by a shutdown to Mode 5 conditions.

We have evaluated the information you provided orally and in your subsequent written request and determined that they adequately support your request for a temporary waiver of compliance. Based on the compensatory and corrective .

9212000060 921201 l PDR ADOCK 05000483 P PDR \

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. DEC 011992 Union Electric-Company 2 actions you specified in your request, the Deputy Regional Administrator, in my absence and with concurrence from NRR, granted the requested relief. on November 27, 1992, to begin at 1746 CST November 27, 1992, and to expire at 1746 CST November 28, 1992. This waiver was granted based on the minimal increase in risk associated with extending the allowed backup power reliance period and the increase in safety by alleviating an unnecessary thermal cycle on the plant that would be experienced if the plant were to be shut down to effect the repairs.- I understand that this waiver of. compliance was terminated with the completion of testing and restoration activities at 0116 CST on November 28, 1992.

A. Bert Davis Regional Administrator

Enclosure:

As Stated cc w/ enclosure:

G. L. Randolph, Vice President, Nuclear Operations -

J. V. Laux, Manager Quality Assurance Tom P. Sharkey, Supervising Engineer, Site Licensing DCD/DCB (RIDS)

OC/LFOCB Resident Inspector, RIII Region IV Resident Inspector, Wolf Creek K. Drey.

Chris R. Rogers, P.E.

Utility Division, Missouri Public Service Cnmmission POR/LPDR Gerald Charnoff, Esq.

Thomas Baxter, Esq.

R. A. Kucera, Deputy Director, Department of Natural Resources

. M. L. Boyle, Te<.hnical Assistant, DRP, I/II, NRR See Continued Distribution

. DEC 011932 Union Electric Company 3 T. E. Murley, NRR J. G. Partlow, NRR W. T. Russell, NRR J. W. Roe, NRR J. N. Hannon, NRR R. L. Wharton, NRR J. Lieberman, OE R. W. Defayette, EICS, Rill 4

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