ML19242C437

LER 79-077/03L-0 on 790705:auxiliary Feedwater Pump Turbine I-1 Steam Inlet Valve M5-106 Would Not Close on Simulated Low Turbine Inlet Pressure Signal.Caused by Component Failure Components Replaced

ML19242C437
Person / Time
Site:	Davis Besse
Issue date:	08/03/1979
From:	Jerrica Johnson TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19242C436	List: ML19242C435 ML19242C437
References
LER-79-077-03L, LER-79-77-3L, NUDOCS 7908100406
Download: ML19242C437 (3)

Text

U. S. NUCLE AR REGUL ATORY CCMMISSION NRC FORM 366 (7 77)

LICENSEE EVENT REPORT r .

(PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION)

CONTROL BLOCK: l l l l l l lh 6

o t lOlH D j B ] S l l l@l 0 l 0 l- l 0 Lir l 0 l N l P l F l- l 0 l 325 l@l 7ti 4 l1 L' l1 l1T) lPE1JOl@lE7 ClA I 58l@

CENSE 7 8 9 LICENSEE CODE 14 15 .WSE NUVdLH CON'T Lolil 5O ILl@

01 510 l- 1013 l ' 16 J@l t2 b) 0 l EV7ENT l 0DATEl 5 l 7 l 9 l@l0REFOHT 74 75 l8 l0 l 3 l 7 l9 l@

DATE Eh>

7 8 60 61 DOCKET NUYDEH EVt:NT DESCRIPTION AND PROBABLE rONSEQUENCES h l

o2 l On 7/5/79 and again on 7/9/79, while conducting surveillance testing an valve M3-106.

l o 13 l l the Auxiliary Feedwter (AFW) Pump Turbine 1-1 Steam Inlet Valve, it was found that itl o 4 lwould not close on a sinulated low turbine inlet pressure signal. There was no dangerj g j j to the health and safety of the public or station personnel. The unit was suberiticall o c !and AFW Train 1-2 was operable. (NP-33 ~9-94) l l0 l 7l l 1

0 8 l 80 CAUSE COVP. VAiV2 SYSTEM CAUSE SUBCODE SUBCODE CODE CODE SUBCODE COYPONENT CODE

[OM8 lClHl@ y @ A l@ l R] El Ll Al Yl X]@ lB @ y@

12 13 14 19 20 7 9 10 11 REVISION SEQUENTI AL OCCURRENCE RCPORT R(PORT NO. CODE TYPE No.

EVEN1 YF AR

@ ,agn'RO LE R a; I 71 91 l--I I 01 7 71 1/1 1013I iL I 9 10l 28 73 JJ 31 32 23 24 26 21

_ 21 e.

B. SUPP l MA L,F AC U En V THb HOURS 22 S E tT D FOR ACT O PLANT TAKEP Z l 0l 0l 0l 40 lYjg y g lAlg lCl6l4l9lg l3t>l@ 31 l

lB 33 lgl34 Z]g l3SZ lg 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h failure. The pins on the control l 3 O lThe cause of both of these occurrences was component 3 i l relays were not making proper contact with their socket. Both relavs have now been 1 I

y,,7, l replaced. Both sockets will be replaced to assure oroper operation.

11 131 l

}

til4 I l 80 7 8 9

% POWE R OTHER STATUS O SCOV HV DISCOVERY DESCRIPTION STA 5 i s l C l@ l 0l D j 0 gl NA l l B j@l Post maintenance surveillance test l ACTIVITY CONTENT LOCATION OF RE LE ASE RELEASED Or RE LE ASE AVOuNT OF ACTivtTY NA li I68 I9 W h Z lgl 7 10 11 NA 44 l

45 80 PERSONNEL E APOSUMES NU"9ER TYPE D E SCRIPTION pn s m v-

- ~- i N ['i p j 1 7 l l l j@lZ lNA

,,g (, ' ~ , 1d /.

PERSONNE L INJURt ES NU'9Et DESCRtPTION g' Q \ { Q. ) 9 (,,;a ' , y U N /J b NA l 7

i a 8 9 10 l0l@l 11 12 80

. - ~

LOSS OF OR O AVAGE To F ACILITY Q ,

TVPE DES n'PT ON v E ' ;'

NA _

l

, 9 lZjgl 7 8 9 to

,ssuE O

7908100406 NRC USE ONLY lll,lllllllll~

j 1210.1 LN hl ESCR PriO~@

7 8 9 10 NA 08 69 60 &

John J. Johnson paong.419-259-5000, Ext. 276 DVR 79-114. ll.hE OF PREPARER

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE S_UPPLEMENTAL INFORMATION FOR LER NP-33-79-94 DATE OF EVENT: July 5, 1979 and July 9, 1979 .

FACILITY: Davis-Besse Unit 1 1DENTIFICATION OF OCCURRENCE: Failure of MS 106 relays R1 and R3 to energize Conditions Prior to Occurrence: The unit was in Mode 4 on July 5, and in Mode 3 on July 9, with Power (MWT) = 0, and Load (Gross MWE) = 0.

Description of Occurrence: On July 5,1979 at 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> while performing Su veil-lance Test ST 5071.04, "Au:.iliacy Feedwater System Channel Functional Test", valve MS 106, Auxiliary Feedwater Pump Turbine Steam Inlet Valve 1-1 from Stean Generator 1-1, would not automatically close as designed on a simulated low turbine inlet pres-sure signal. Since the unit was in Mode 4, the Auxiliary Feedwater System is not required, and no Action Statement was entered. The system was repaired and declared operable at 0145 hc urs on July 6,1979. This occurrence is being reported to docu-ment a component f:ilure.

A similar f ailure. of MS 106 occurred on July 9,1979 at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br /> while ST 5071.04 was being performed to assure operability af ter maintenance on a failure of a torque switch which occurred on July 8,1979 at 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> (Licensee Event Report NP-33-79-85). The unit was in Mode 3 aad still 2n the Action Statement of Technical Specification 3.7.1.2 (as of July 8) which states, "With one Auxiliarv Feedwater System inoperable, restore the inoperable system to operable status wit' 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in Hot Shutdown (Mode 4) within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />". The system was repaired and declared operable at 0245 hours0.00284 days <br />0.0681 hours <br />4.050926e-4 weeks <br />9.32225e-5 months <br /> on July 10, 1979, approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> af ter the Action Statement was entered.

Designation of Apparent Cause of Occurrence: MS 106 was not operating because closing relays R3 and later R1 were not energizing. The relays were initially replaced with new ones but R3 still did not function. The problem was cetermined to be bad contact between the relay pins and the socket base. It was corrected by bending the pins on R3 out slightly. The second failure on July 9 was corrected by spreTding the pins en RI.

Analysis of Occurrence. There was no danger to the health and safo ty of the public or to station personnel. During the first occurrence the unit was in Mode 4 and auxi-liary feedvater was not required. During the second occurrence, the unit was subcri-tical and Auxiliary Feedwater Train 2 was operable.

Corrective Action: The first occurrence was investigated under Maintenance Work Order 79-2441. The R1 and R3 relays were replaced, and the pins on the R3 relay were spread apart to assure good contact. ST 5071.04 was perforned on July 6, 1979 to verify operability.

8 LER #79-077 b2h

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLEMENTAL INFOR3MTION FOR LER NP-33-79-94

\

79-2458. The The second occurrence was investigated under 10, 1979 Maintenance to verif y operability, Work relay. ST 5071.04 was performed at 0245 hours0.00284 days <br />0.0681 hours <br />4.050926e-4 weeks <br />9.32225e-5 months <br /> on JulyNew sockets will be installed on both removing the unit from the Action Statement.

the R1 and R3 relays to insure proper operation.

There have been other relay f ailures but none identified to have been Failure Data:

caused by poor contact between the pins and th.' socket base.

LER #79-077

\

.