PNO-IV-89-040, from 890622-23,power Exceeded 82% & Secondary Heat Balance Indication in Control Room Read Approx 79.2%.On 890623,discovered Incorrect Input Into Secondary Heat Balance Calculation.Power Reduced to 65% Pending Evaluation

PNO-IV-89-040:from 890622-23,power Exceeded 82% & Secondary Heat Balance Indication in Control Room Read Approx 79.2%.On 890623,discovered Incorrect Input Into Secondary Heat Balance Calculation.Power Reduced to 65% Pending Evaluation

ML20246A772
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/23/1989
From:	Westerman T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-89-040, PNO-IV-89-40, NUDOCS 8907070082
Download: ML20246A772 (2)

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[ PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-89-40 l

! . l L .This preliminary notification constitutes EARLY notice of events of POSSIBLE l safety or public interest significance.- The information is as initially received {

.without verification or evaluation, and is basically all that is known by the i

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Region IV; staff on this date.

FACILITY: Public Service Company of Colorado Licensee Emergency Classification:

Fort.St. Vrain Notification of Unusual Event DN:. 50-267 Alert Site Area Emergency i General Emergency X Not Applicable

SUBJECT:

OPERATION AB0VE AUTHORIZED POWER LEVEL By letter dated July 2,1987 (Murley to Williams), Fort St. Vrain was authorized to operate at power levels not to exceed 82 percent of full power. By corrected secondary heat balance calculations, it appears that. power exceeded 82 percent from approximately 10:20 p.m. on June 22, 1989, until approximately 2:30 a.m. on June 23, 1989. The maximum calculated secondary heat balance power level during this period was approximately 83.6 percent. That power level is still under review by the licensee During this period, the secondary heat balance indication in the control room read approximately 79.2 percent. The linear power channels of nuclear ,

instrumentation read between 79.5 and 81.4 percent power.

At approximately 2:30 a.m. on June 23, 1989, the licensee discovered an apparent incorrect input into the secondary heat balance calculation (data logger). When this input was corrected, the indicated secondary heat balance power level changed from 79 to 82.5 percent. Power was immediately reduced below t 82 percent. The licensee's evaluation of the interval during which the incorrect input was used for the secondary heat balance calculation indicated that the actual power level may have reached 83.6 percent at one point.

The licensee has reduced power to 65 percent until an evaluation of this event and a determination of root causes, corrective actions, and actions to prevent a l recurrence are implemented. The NRC resident inspector is onsite.

The licensee paid a $75,000 civil penalty in 1986 for exceeding a 35 percent power limitation which was in effect at that time, though the circumstances of that event were different from the present one.

Neither the licensee nor the NRC plans to issue a press release.

The state of Colorado will be informed.

C:DRP/B TFWesterman:cs D:DRP JLMilhoan RA RDMartin  % 0\

6/23/89 6/23/89 6/23/89 0 82 390623 FNO-IV-89-040 PDC

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', Region IV received notification of this occurrence from the HQ 00 at 1:30 p.m.-

l (EDT). Region,IV has informed the ED0's office, the NRR project manager, and

-the region's public affairs. officer.

-This^information'has been confirmed with a licensee representative.

CONhACT: T.IF. Westerman,-FTS 728-8145 a1 DISTRIBUTION:-

OWFN NMBB NL MAIL: DCS (Orig. IE34)  !'

'Chmn. Zech SECY NM55 XEDIT 'RES D0T (Transp. Only)

Comm. Roberts' CA NRR- ARM (7 /nsro}/89 Comm. Carr-

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GPA-01A 01 OGC FAX:

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Comm. Curtiss PA ' SLITP H-St PDR ACRS ED0 OE TDT HSAC EW-W RRI _.

%5EXP NRC Ops Ctr Licensee (Reactor)

NRCRES, RESPN Research (Paula Dorm)

NRCRM, AE0D AE0D(Patty _ Wilson)

NRCRM.. BROWN ARM (Karen Brown)

'NRCRMP, 01ADW Inspector & Auditor (Displaywriter/PC)

'NRCRMP, 01DW Investigations (Displaywriter/PC) '

INRCO2, OPAPN~ GPA:Public Affairs (Glady Ordaz) 1 INRC0304,~ SLIPN GPA: State / Local Indian Tribes Program (Brenda Hill) l INRC0304, NMSSPN Nuclear Material Safety & Safeguards (Pat Graaf)

INRC0506, NMSSPN Nuclear Material Safety & Safeguards (Cathy Jenkins)

> '1NRC0708, OEPN Enforcement (Betty Summers)

INRCI112, NRRPN 'NuclearReactorRegulation(DonnaBerean) 1NRC1516, 0GCPN- General Counsel (Edna Downs)'

INRC1718, ZECHPN Chairman'(Lois Altoft)

INRC1718 -ED0PN Executive Director for Operations (Doris Day) ,

INRC1718, OCAPN GPA: Congressional Affairs (Janice Hester)

'NRCRI. RIPN Region I NRCRII, RIIPN Region II NRCRIII, RIIIPN Region III I NRCRIV, RIVPN Region IV NRCRV, RVPN . Region V 1

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