ML20010B504

LER 80-015/03X-1:on 800210,control Rod 5-11 Absolute Position Indication Declared Inoperable Due to Numerous Asymmetric Rod Alarms.Apparently Caused by Defective Absolute Position Indication Reed Switch Assemblies

ML20010B504
Person / Time
Site:	Davis Besse
Issue date:	08/04/1981
From:	Werner J TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17275B377	List: ML17275B376 ML20010B493 ML20010B495 ML20010B497 ML20010B499 ML20010B500 ML20010B501 ML20010B503 ML20010B504
References
LER-80-015-03X, LER-80-15-3X, NUDOCS 8108170119
Download: ML20010B504 (2)

Text

• ;rownc, ,

a LICENSEE EVENT !dPORT CONTHOL DLCCK: l l l l I l l (PLE ASE PRINT OR TYPE Att REQUIRED INFORMATION) 1 O h l1l l 0l Hl Dl Bl Sl 1l@l0 l0 l 0 l0 l0 l 0 l 0 l 0 l0 l0 l 0 l@l h 4

26 l 1LICENSE l 1 l lTVPEj 1JGl@lsi BAT l Sd lg 7 4 3 LICEN3(E LO.;E It 15 LICrASE NuVdEH CCN'T E 7;$$ ll l@l 0 l 5 l 0 l- l0 l 3 l4W jf p l0 l2 l1 l0 l8 l0l@l0]8l0l4l8[1]@ b9 EVENT OAfg 74 75 REPCRT OATE $J

1. 3 t4 bl OOCK ET NL?.'0Ea EVENT DESCRIPTION AND PRCBA8LE CONSEQUENCES h

[TTT1 1 On February 10.1980 at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> during a normal startup, Control Rod 5-11 absolute l l3l3ll position indication (API) was declared inoperable due to numerous asymmetric rod g l9l.:ll alarms. This placed the unit in the action statement of Technical Specification j l9l3l l 3.1.3.3 which required the position of tl.e control rod to be verified by actuating r; s I one of its zone reference indicators. There was no danger to the health and safety l lTTTl I of the public or station personnel. The control rod did not vary from its intended  ;

oa i position, only the API was faulty. (NP-33-80-21) l 83 7 6 9 #

COI[E "^"o*E CO St$s#"

CO oE CO noNENT CoOE SusE70'E SENE

.;Q l I l E l@ M@ U @ l T I N ' S l T l R l U lh Wh (_Z_j h 23

8 9 10 11 12 IJ 16 19

^

• SEQUENTIAL OCCURRENCE REPORT REVISfoN

,,,, EVENT YE AR R EPORT NO. CODE TYPE No.

l b ,"LER/80 l0l1l5l y l0l3l ( --J l21 8l22 0l [--J u,EE [XJJ l ll l1 _ 2J 24 2ti 27 28 23 30 34 32

' ' vEI5IONUw

! YAE7 'fcW5! O((tEIT TEMCS" wouns #S S a T TS! U F E EiSNa. S"'EdLiED

$1 l33Xl@l34 Xl@ l35Z l@ lZ l@ lOl01O@l0lQ@ W@ lNl@ lD l1 l5 l0 l@ -

36 31 40 di 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS @

l PTO7 I Investigation has revealed the apparent cause to be defective API reed switch l i -

i i l assemblies. A major contributing cause of this failure is the excessive temperatures, to which the assemblies and their cables were subjected, due to a procedure deficiency.

! gl lI gl Under FCR 79-413 a new "R4C" API system with built-in channel redundancy and high l

(

l t gl temperature API cables was installed. l

' 80 7 8 9

% POWE R oTHER STATUS ISCO RY DISCOVERY DESCRIPTION I ST S Lis (_D_j@ l 0 l 1 l 7 l@l NA l l Al@l during startup l A TivlTY- CO TENT RELEASED OF RELEASE AP.touNT OF ACTIVITY LOCATION OF PELEASE NA l l NA l JTsl

' 7 LzJ 8 C

@ l z l@l to tI 44 45 80 PERSONNEL EXPOSURES TYPC DESCRtPTION

• NUMBER ,

l R'

l' 10101 ' Ol@l zl@l NA

,eRSO%EL,N;uLS Nu mR oESCniPTiO~@ l JE1101010181

I 8 9 11 12 w^

80 LOSS OP OR DAMAGE TO PActLtTY

• TYPE DESCRIPitON l

lilol39,i zl@!

' 0 NA 80

'"'" NRC mc om ,

eSue

'iTEl I ni@0ESCRiPfioNg l NA  ! l I I l I I I -I l ' I ! ! 7 l 8108170119 810804 John Werner 2 ' *

,poN E: $

i DVI hDRADOCK 05000346 PH -

~

.4 TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-80-21 DATE OF EVENT! February 10, 1980 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Control Rod 5-11 Absolute Position Indication (API)

Failure Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 471, and Load (Gross MWE) = 156.

Description of Occurrence: On February 10, 1980 at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />, Control Rod 5-11 API was declared inoperable due to numerous asymmetric rod alarms. This placed the unit in the action statement of Technical Specification 3.1.3.3 which permitted continued unit operation if the position of the control rod and its group is main-tained and periodically verified at one of the zone reference positions. The rod position was verified at its 100% withdrawn position per the action statement, and the rod position indication was placed in asymmetric bypass.

Designation of Apparent Cause of Occurrence: After several months of collecting data on control rod 5-11, the apparent cause has been determined to be defective API reed switch assemblics. A major contributing cause to this failure is the excessive y

temperatures to which the assemblics and their cables were subjected. This occurred during several months of operation in which the head assembly cooling fans were not in operation due to a deficient procedure which allowed restart following the 1978 outage without reconnecting the cooling fan power cables. The Reactor Vessel Closure Head Removal and Replacement Procedure, SP 1504.01, was corrected.

Analysis of Occurrence: There was no danger to the health and safety of the public or station personnel. The control rod did not vary from its intended position, only the API was faulty.

Corrective Action: During the last shutdown in February,1980, an additional test connection was made at the inner containment electrical penetration at exiating

' butt splices in the API cabling. This was done under FCR 79-424, Rev. A, sad as a continuing corrective action to similar occurrences reported under Licenset Event Reports NP-33-79-141 and NP-33-80-07.

Under Facility Change Request 79-413, a new "R4C" API system was installed. This i

3 system features built-in channel redundancy and high temperature API cables..

Failure Data: There have been previous failures of control rod APIS. Control Rod 5-il's current symptoms were previously reported in Licensco Event Reports NP-33-79-141 and NP-33-80-07.

LER #80-015

~--