ML19282A773

LER 79-021/03L-0 on 790205:containment High Pressure Alarms Were Received & Safety Features Actuation Sys Channel 2 Erroneously Tripped.Cause Unknown.No Deficiencies Found from Surveillance Tests.Channel Returned to Operation

ML19282A773
Person / Time
Site:	Davis Besse
Issue date:	02/28/1979
From:	Kovach S TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19282A767	List: ML19282A766 ML19282A773
References
LER-79-021-03L, LER-79-21-3L, NUDOCS 7903060474
Download: ML19282A773 (2)

Text

U.S. NUCLEAR REGULATORY COMMISSION NRC FORM 366 (7 77)

LICENSEE EVENT REPORT (PLE ASE PRINT 081 TYPE ALL REQUIRED INFORMATION)

CONTROL BLOCK l 1

l l l l l lh 6

1 lj1l1l@l l lg lo l1l 7 8 9 l 0] LICENSEE Hj DjCODE Bl Sl 1lglS0 l0 l- l0LICENSE 14 I l0 lN lP lF l- l0 l3 jgl4 NUM8EH 25 26 LICENSE TY PE JG 51 C A T $8 CON'T L@l l5 l0DOCKET l- [0 l3 l4 l6 }@l 01 21 0 ! 5l 7 l 9 l@l 0REPORT l 2 lDATE 2 l 8 l807 l 9 l@

"E OA l0l1l 3o(,pC 60 61 NUYSER 6d 63 EV"NT D ATE 74 75 7 8 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l ITTTl i At 1807 hours0.0209 days <br />0.502 hours <br />0.00299 weeks <br />6.875635e-4 months <br /> on 2/5/79, Containment High Pressure Alarms were received and Safety

[ o l a l l Features Actuation System (SFAS) Channel 2 tripped f rom an erroneous containment high l l o l 4 l l pressure signal. The duration of the high pressure signal was less than one second. 1 l

O s l During this time the unit was placed in Action Statement 9 of Tech Spec 3.3.2.1.

The l l o 16 I l There was no danger to the health and safety of the public or unit personnel.

l 0 7 l bistable tripped icmediately, and the three remaining SFAS containment high 0 a 1 pressure instrument strings were operable. (NF-33-79-26) _!

80 SUBCO E COMPONENT CODE SUBC DE SU ODE C DE CODE I O_L]

8 l Il Bj@ l Xl@ [ X l@ lX XlXlX 9 to 11 12 13 X lX l@ {@ ]@

16 19 20 7

REPORT REVISION SEQUENTI AL OCCURRENCE CODE TYPE NO.

EVENT YEAR REPORT NO.

O ,agg LER RO 17191 l- 10 2 l1 l l-l le l3 l l tl l_] l0 l u 28 2') 33 31 32 22 23 24 26 27

_ 21 HOURS 22 IT$IO FOR 1 B. SU PLIE MAN FA TURER AKE A x;

ON PL NT gg . Tzlg 0 ;0 0 hr ; SS8gg in ;g x g ;x ; x; x xg 33 x jg;34T O'g 35 36 3/ 40 41 42 43 44 47 CAUSE DESCRIPTON AND CORRECTIVE ACTIONS gi;ogjNo specific cause has been found for the momentary spike in containment pressure. Thel Both I ji ;ijl instrument st ring was inspected but the cause of the spike was not discovered.

I g g the monthly a nd refueling surveillance tests were performed but no deficiencies were l

,,3; gdiscovered. The channel was returned to operation.

l 1 4 l 80 7 8 9 OTHER STATUS ISCO RY DISCOVERY DESCRIPTION STA S *6 POWER

[1_l,5_j @ l0 l8 l7 l@] NA l lAj@l NA l ACTIVITY CONTENT LOCATION OF RELEASE RELE ASED OF RELEASE AMOUNT OF ACTIVITY

@ NA l l NA l 7

1 6 8 9 10

@l 11 44 45 80 PERSONNEL EXPOSURES NUV8ER TYPE DESCRIPTION NA I LLLLI I 01 01 0_]@l zl@l "

,ERSONNELINJES NUYBER DESCRIPTION l

I IB8 I9 e 7

0 01 @ l12 11 NA 80 LOSS OF OR DAYAGE TO FACILITY .

TYPE DESCRIPTION NA l i o I zi@l10 80 7 8 9

'"" 7003QM +, 790306047 NRC USE ONLY ,

,SSUl[@ollCR,,nON@' ll[]lllllllllj 2 O IN l NA 68 69 80 7.

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i DVR 79-030 ,,., , ,,n PAnen Susmi A. Kovach pggyg_.

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLE! ENTAL INFORMATION FOR LER NP-33-79-26 DATE OF EVENT: February 5, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Safety Features Actuation System (SFAS) Channel 2, containment high pressure trip Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2406.2, and Load (Gross MWE) = 785. .

Description of Occurrence: At 18:07:52 hours on February 5,1979, Containment High Pressure Alarms P311 and P899 were received and Safety Features Actuation System (SFAS) Channel 2 tripped from an erroneous containment high pressure signal

( > l8.4 psia) . The duration of the high pressure signal was less than one second.

During this time, the unit was placed in Action Statement 9 of Technical Specifica-tion 3.3.2.1. Technical Specification 3.3.2.1 requires all four containment high pressure SFAS channels to be operable in Modes 1, 2, and 3. Action Statement 9 allows operation to proceed provided the inoperable channel is placed in the tripped condition within one hour and the remaining three containment high pressure instrument strings are operable.

Designation of Apparent Cause of Occurrence: No specific cause has been found for the momentary spike in containment pressure. Under Maintenance Work Order I&C-167-79 the instrument string was inspected but the cause of the spike was not discovered.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. The bistable tripped immediately and the three remaining SFAS containment high pressure instrument strings were operable.

Corrective Action: At 2010 hours0.0233 days <br />0.558 hours <br />0.00332 weeks <br />7.64805e-4 months <br /> on February 5,1979, Surveillance Test ST 5031.01,

" SEAS Monthly Test" on SEAS Channel 2 was successfully completed to verify operabi-lity. Surveillance Test ST 5031.03, " Containment Pressure Inputs to SFAS Refueling Calibration" was performed on February 15, 1979 for further investigation but no deficiencies were discovered. Since the trip was of such a short duration and there have been no previous SFAS channel containment high pressure trips, no correc-tive action other than continuing to monitor this problem can be taken. Should this problem become repetitive, further investigation will be carried out.

Failure Data: There has been no previous reported occurrence of an SFAS channel containment high pressure trip.

LER #79-021