ML19207B117

LER 79-084/01T-0 on 790806:containment Air Coolers Svc Outlet Valves,Automatically Regulated by Inlet Air Temp, Failed to Meet Response Time.Caused by Design Error in Actuator Air Opening Size.Valves Will Be Redesigned

ML19207B117
Person / Time
Site:	Davis Besse
Issue date:	08/17/1979
From:	Rudolph J TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19207B116	List: ML19207B115 ML19207B117
References
LER-79-084-01T, LER-79-84-1T, NUDOCS 7908230390
Download: ML19207B117 (2)

Text

U. S. NUCLE AR REGUL ATORY COMMISSION AC FORM 366

'77)

LICENSEE EVENT REPORT l l l l l (PLE ASE PRINT OR TYPE ALL REQUIRED INFORMATION)

CONTROL BLOCK: l l 1

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LJCENSE TYPE JJ 14 f6 LICE NSE NLYtiLH 8 9 LICENSEE CODE CON'T '

i 4 l 6p 0 l 8 l 0 l6 l 7 l 9 Ql 0 l 8 lHEFOHT 1 l 7DATEl 7 l 980l@

S$"CE lEl@ 61O l 5lbl 0 5 EVENT OATE 74 75 63 8 f>0 DOCK E T NU*."J E H _

EVENT DESCRIPTION AND PROB AOLE CONSEQUENCES g) a reportable 1 o 12 j l During a review of Facility Change Request 79-259, it was determined that event may have occurred. The containment air coolers service water outlet valves l

o a Since these valves arg failed to meet the response time specified in T.S. Table 3.3-5.

o a times have been closed j o 5 l automatically regulated by inlet air temperature they may at The coolers were functional; j

,o 6 enough to preclude operation within the specified time.

Also, the redundant con- [

o 7 l only the service water outlet valve may have been affected.

io s tainment spray systems were fully operable. There was no effect on public or personnelj safety.60 7 8 9

" # SUBC DE Su E (NF-32-79-10)

• SEE CEDE stS CEE COMPONENT CODE fG 9 l Sl B j@ {@ l Aj@ l Vj 11 12 IJ Al L V l 0 lP l@ ] @ lZ @ 18 13 20 REV8SION 8 9 to 7 OCCURHENCE REPORT SEQUE NTl AL NO.

,_ CODE TYPE LER

@ REl,y'40 l7 19 l EVENT YEAR

(- .-j l0 REPORT NO.

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_2l 22 SU PLIE PJA FA T FH HOURS 22 S B iTT D FOR [Uts.

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[ 0l 0l 0l l [ Yl@ lN Q lXl@ l Hl 0l 3 l 5 g l33F lglJ4F lg l3d Zjg l36Zl@ 3/ 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS The valves pneumatic actuators were designed with an undersized air opening. The valqes o l have now been forced full open by changing controller setpoints from 120 to 50 r, ,

jig,jg g,,,,g During the 1980 refueling, the valve actuating mechanisms redesign will be implemer.teq j

j,g3; [

to correct the stroke time.

11 1411 80 7 8 9 BISCO F DI OTHER STATUS STA 5 %P j B j Surveillance kCOVERY 'e s t CESCRtPTION l

, 3 g l1 l b*,E Hl0 gl NA ACTIVITY CONTENT LOCATION OF RELE ASE RELEASLD OF ' ELE eE AVOUNT OF ACTIVITY NA l li is t i Z i @ Lzj@l NA l 60 44 45 7 8 9 to 1t PERSONNEL ( XFOSUHES NOVt4ER TYPF DESCHIPTION l

NA l 1 l 7 l l 0 l 0 l 0 l@l Z @l 3 PEHSONNE L INJL6 IES ;D

[ 3 NUURE H DESCRIP TION j Na i H 8 9 1010101@i 11 12 80 7

LOSS OF OR D AY ACE TO F ACillTY TYPE D E SCHip TION l

liI91IZl@l is 9 to NA 7 NRC USE ONLY _

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2 o Whl ESCRIPTION NA " " "

4"19-259-5000, Ext . 299

> 8 e >0 DVR 79-126 NAaae or enEPARER James P. Rudolph 7 9 9 3 .M O MPt ONE.6 {

g TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUP?LEMENTAL INFORMATION FOR LER NP-32-79-10 DATE OF EVENT: August 6, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Slow response on containment air cooler service water outlet valves Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2772, and Load (Gross MWE) = 920.

Description of Occurrence: During a review of Facility Change Request 79-259, it was determined that a reportable event may have occurred in that the containment air coolers service water outlet isolation valves failed to meet the response time re-quirements of 45 seconds f rom Table 3.3-5 of Technical Specifications. Technical Specification 3.6.2.2 requires two operable coolers in Modes 1, 2, and 3. Since the valves in question are automatically regulated by the cooler inlet air tempera-ture, the valves may have been throttled to the extent that at times they would not have opened within the allowable time . Theref ore, this incident is being reported as per Technical Specification 6.9.1.8.1.

Designation of Apparent Cause of Occurrence: The valve actuating circuit has a design deficiency. The long response time of the valves is due to the slow bleedoff of air from the valve's pneumatic actuator.

Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. The containment air coolers were functional in all modes of operation; only the response time of the service water valves may have been somewhat degraded.

Corrective Action: Facility Change Request (FCR)79-259 had been previously written ar.d haplemented on June 25, 1979 to change the setpoints on the air cooler service water outlet valve controllers from 1200F to 50 F. This forces the valves to remain in a full open position thereby climinating the response time requirement.

FCR 79-280 was initiated to modify the valve actuating apparatus on SW 1336, 1357, and 1358 to bring their response times within the required limits. This FC't is scheduled to be implemented during the 1980 refueling outage.

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

LER #79-084 D 1147