ML19296C575

LER 80-009/03L-0:on 800122,discovered That NI-7 Indication on Computer Group 38 Was Reading Less than Heat Balance Power,Putting NI-7 Below Instrumentation Operability Limit Line.Caused by Extremely Tight Calibr Band at 100% Power

ML19296C575
Person / Time
Site:	Davis Besse
Issue date:	02/15/1980
From:	Werner B TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19296C573	List: ML19296C572 ML19296C575
References
LER-80-009-03L, LER-80-9-3L, NUDOCS 8002260673
Download: ML19296C575 (2)

Text

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• LICENSEE EVENT REPORT

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(PLE ASE PRINT OR TYPE ALL HEQUlHED INFORMATION)

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d bJ b: C O ; s E T *. W .2 E 1 tA t) LVENT DATE 14 15 HEPQH T DAT E SJ EVENT DES:RIPil0N AND PRO 3AGLE CCCECUENCES h

,a 2 l On January 22, 1980 at about 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />, an operator noticed that NI-7 indication on l o!3 l computer Group 38 was reading less than the heat balance power, putting NI-7 below

.o 4 l the NI operability Limit line of ST 5030.01, Reactor Protection Systen Daily Heat l 9 s l 5 1ance Check. NI-7 was declared inoperable at 1328 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.05304e-4 months <br />. The unit entered the  ;

o c l action statement 2 of T.S. 3.3.1.1. There was no danger to the public or station per-l 917 l sonnel. Ilea t balance power was less than 100*: at all times and itss than the other l

~ 0 a j indicated power of NIs 5, 6, and 8. (NP-33-80-12) l d 9 60 SYSTE M CAU5i CAUSE COYP. VatVt CODE COCE SUSCGCE COY'ONENT CODE SUSCOCE SUeCOCE o 9 I I I Dj @ Lnj@ l A lh l Z l Z l Z l Z l Z l Z lh l Z l@ l Zl @

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CAUSE OLSCNPTION AND CORRECTIVE ACTIONS h 2 o l The cause is an extremely tight calibration band at 100% power (see LER NP-32-79-15) l i i l coupl ed wi th a + 0. 47, variat ion in indica ted power and heat balance power due to nor-l

, , [ mal plant control variations. N1-7 was recalibrated per ST 5030.11, checked per l

,3 l ST 5030.01, and declared operable at 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on January 22, 1980. The tripped j i 4 condition was cleared, and the unit was taken out of the action statement. l 6 9 80 FACtLITY YETHOD CF STATUS  % POWE FI OTHE R STATUS DISCOVERY OlsCOVERY DESCHIPTION -

i s 8 9 LEj@ l 1 l 0 l 0 l@l NA 13 12 44 l [AJgl operator observation l 13 45 46 80 AC TIVI TY CON TE NT RELEASED Or AE LE ASF AMOUNT OC ACTIVITY >

LOCATION OF RELEASE 1 6 8 9

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PERSONNEL FxPOSuaES NUUBER TYPE DESCRIPTION i 7 10101 Ol@LZj@l NA l 9 9 11 12 13 80 PE RSONNE L INJUHl($

NUYM H . D's:n0 TION i a S 9 101010!@l ft 12 NA I 80 LOSS OF On D avage TO F AClllTY .

TYPE CE Scrup Tf 0N i 9 NA 8 9 LZJ@lIJ l SO l% SUE E CRIPTIGN hL Ob f 8, 2 o 8 9 LNhl tu NA l 68 69 lll llll]lll l2 e0 i T B. J. Werner 419-259-5000, Ext. 231- o .

JVR 80-017' NAME OF PREPAREH PHONE: ', i.

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TOLEDO EDISON COMPANY DAVIS-BESSE SUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-80-12 DATE OF EVENT: January 22, 1980 FACILITY: Davis-Besse Unit 1 NI-7 Reactor Protection System (RPS) Channel 4 out of IDENTIFICATION OF OCCIIRRENCE:

calibration The unit was in Mode 1, with Power (MWT) = 2765.5 Conditions Prior to Occurrence:

and Load (Gross MWE) = 921.

Description of Occurrence: On January 22, 1980 at about 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />, it was noted the NI-7 indication on computer Group 38 was reading less than the heat balance that line of ST 5030.01, RPS Daily power, putting NI-7 below the NI operability limitAfter two subsequent computer updates of Heat Balance Check.

showed NI-7 indication less than the heat balance power, NI-7 was declared inopera-ble at 1328 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.05304e-4 months <br />. This placed the unit into the Action Statement 2 of Table 3.3.1 of Technical Specification 3.3.1.1, which required the channel to be tripped within one hour. RPS Channel 4 was place d in a tripped condition at 1336 hours0.0155 days <br />0.371 hours <br />0.00221 weeks <br />5.08348e-4 months <br />.

This occurrence is due to the extremely Designation of Apparent Cause of Occurrence: 100% power (see LER NP-32-79-15),

tight calibration band that we are limited to at coupled with the approximately 10.4% variation in indicated power and heat balance power due to normal plant control variations. For the NI calibration to remain with-in the operating band for any length of time with the inherent variations in power, would require alignment accuracies greater than we are capable of at present.

Analysis of Occurrence:

There was no danger to the health and safety of the public or to station personnel. Heat balance power was less than 100% at all times and less than the indicated power of NIs 5, 6, and 8.

Corrective Action: NI-7 was recalibrated per ST 5030.11, RPS Power Range Calibration, checked satisfactorily per ST 5030.01, RPS Heat Balance Check, and declared operable at 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on January 22, 1980. The tripped condition was cleared, and the unit was taken out of the action statement.

Failure Data: There have been no previous similar reportable occurrences.

LER #80-009