ML17342A983

Special Rept:On 870922,quadrant Power Tilt Ratio (QPTR) Found to Be in Excess of 2% During Startup After Refueling. QPTR Calculated Every Hour Until Less than 2%.New Nuclear Instrumentation Sys Detector Calibr Currents Calculated

ML17342A983
Person / Time
Site:	Turkey Point
Issue date:	10/21/1987
From:	Woody C FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
L-87-423, NUDOCS 8710260312
Download: ML17342A983 (4)

Text

REGULATORY RMATION DISTRIBUTION SYS 1 (RIDS)

AC(iESS ION NBR: 8710260312 DOC. DATE: 87/10/21 NOTARIZED: NO DOCKET FACIi': 50-250 Turkey Point Planti Unit 32 Florida Poujer and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION WOODYI C. O. Florida Poujer 5 Light Co.

RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept: on 870922I quadrant poujer tilt ratio (GPTR) found to be in excess of 2/ during startup after refueling.

GPTR calculated every hour until less than 2/. New NIB detector calibr currents calculated.

DISTRIBUTION CODE: IE22D COPIEB RECEIVED: LTR TITLE: 50.,73 Licensee Event Report (LER)i

/ ENCL Incident g etc.SIZE:

Rpti RECIPIENT COP I ES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 McDONALD> D 1 1

' ACRS MOELLER 2 '

INTERNAL: ACRS MICHELSON 1 AEOD/DOA 1 AEOD/DSP/NAS 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 DEDRO 1 . 1 NRR/DEST/*DS 1 0 NRR/DEST/CEB 1 1 NRR/DEBT/ELB 1 1 NRR/DEST/ICSB 1 1 NRR/DEST/MEB 1 1 NRR/DEST/MTB 1 1 NRR/DEST/PSB 1 1 NRR/DEST/RSB 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 1-NRR/DLPG/GAB 1 1 NRR/DOEA/EAB 1 1 NRR/DREP/RAB 1 1 NRR/DREP/RPB 2 2 LCD. /SIB 1 1 NRR/P MAS/ ILRB 1 1 1 RES DEPY GI 1 1 RES TELFORDI J 1 RES/DE/EIB 1 1 RQN2 F I LE 01 1 1 EXTERNAL: EGSG QROHI M 5 5 H ST LOBBY WARD 1 1 LPDR 1 NRC PDR 1 1 NSIC HARRISI J 1 1 NSIC MAYSI G 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

P. O. BOX 1, JUNO BEACH, FL 3340B.0420

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~sg OCTOBER 2 1 f987 L-87-423 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gent lernen:

Re: Turkey Point Unit 3 Docket No. 50-250 Special Report - Radial Flux Til t Greater Than 2% (Voluntar Re ort)

In accordance with Technical Specification 6.9.3.I the attached voluntary Special Report is provided for your information.

Should there be any questions on this information, please contact us.

Very truly yours, C. O. Wood Group Vic esident Nuclear Energy COW/TCG/gp A t tachment cc: Dr. J. Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant 8710260312 871021 PDR ADOCK 05'000250 y& /(

S PDR SDF I /004/I an FPL Group company

SPECIAL REPORT Turkey Point Unit No. 3 October 21, 1987 RADIAL FLUX TILT GREATER THAN 2 X PURPOSE:

Technical Specification (TS) 6.9.3.1 requires that if the quandrant power tilt ratio exceeds a value of 2X for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, except for physics and rod exercise testing and if design hot channel factors for rated power are not exceeded, an evaluation as to the cause of the descrepancy" shall be made and submitted as a report to the Commission. On September 22'987'the Quadrant Power Tilt Ratio (QPTR) was found to be in excess of 2X at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />, and was returned to less than 2X in 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />. This report is thus for information only, and is not the result of any Technical Specification requirements or violations since the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> limit was not exceeded.

EVENT:

When Unit 3 started up after refueling, all of the zero power physics test results were within their acceptance criteria. During the initial power ascension on Septemer 13, 1987, the reactor power was held at 30X to perform the first power distribution flux map and for chemistry.

The results of this flux map showed the Hot Channel Factors (HCF) to be well within their limits for 30X reactor power, but the incore radial tilt showed a value of +4.50X. At the time the flux map data was analyzed, the reactor had been shut down for the turbine over speed test. It was decided that on the subsequent power ascension, a second power distribution flux map would be taken at 30X reactor power. In order to improve the measured incore radial tilt, it was decided that this second flux map would be taken with Control Bank D further out. Data collection for the second 30X power flux map was completed at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> of September 22, 1987. The results of this second map again showed the HCF to be within their limits for 30X power and the incore radial tilt improved to 4.11X. At this time the Westinghouse core designers were notified, and the Technical Specifications were reviewed. The incore radial tilt is not limited by Technical Specifications, but the QPTR is limited to less than 2X, and is calculated by use of the excore Nuclear Instrumentation System (NIS) detectors. The Control Room was notified at 1900,hours on September 22 of the incore radial tilt, and were requested to perform a QPTR calculation. The calculated QPTR was 8.9X. It was known that 2 of the 4 power range detectors had been replaced during the refueling, and that the affected channels had not been recalibrated. Prior to this event, the plant was already planning to perform a full recalibration of all four NIS channels and remeasure incore radial tilt prior to increasing

~ actor power above 50X. To meet the intent of Interim Technical Specification (ITS) 3/4,2.4 the QPTR was calculated hourly as per ITS 3/4.2.3.2.1. The other conditions of ITS 3/4.2.4 were met because the reactor was in initial power ascension, the High Flux trips were already preset at 80X power, the reactor power was well below the limiting power from the QPTR, and the HCF were within their limits. The plant developed a plan to reduce the QPTR to (2X, and this involved using the two 30X power flux maps to develop new 100X power NIS detector currents and to have the Reactor Control Operator (RCO) borate the reactor to get the Control Rods further out. The new 100X power NIS detector currents were calculated at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> on September 23, 1987.

At 1555, the QPTR calculation was less than 2X.

CAUSE OF THE EVENT:

The incore radial tilt was measured at greater than 2X during the Unit 3 start-up after refueling. This was not considered a highly significant condi-tion considering the reactor power level, the effect of the control rod position and xenon on flux distribution, and the measured HCF being within their limits. The Westinghouse core designers were notified of the condition. The QPTR was calculated as a result of the incore radial tilt and this value was 8.9X. The Turkey Point current and revised Tech-nical Specifications do not require the QPTR to be less than 2X below 50X r'eactor power. However, the ITS require QPTR to be less than 2X for all of Mode 1 and Mode 2. Because the ITS is more restrictive, the Plant entered ITS 3/4.2.4.

CORRECTIVE ACTION:

1) The QPTR was calculated once an hour until it was less than 2X.

2) The Plant stayed well below the limiting power for the QPTR value, the High Flux Trip setpoints were already set at 80X, and the HCF were within their limits.

3) New NIS detector calibration currents were caluclated using the two 30X power flux maps .

4) The controlling bank was withdrawn to a higher position in the core.

5) The QPTR value was less than 2X within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of its first being calculated at 8.9X.

6) The Reactor Supervisor discussed the event with the Senior Resident NRC Inspector and a visiting NRC Inspector from the Regional office.