ML19210F010

LER 79-030/03L-0:on 791110,during Steady State Operation, Increasing Trend in Torus Water Level Observed.Caused by Leaking Bypass Valve for Torus Level Transmitters.Water Indication Restored Per Tech Specs

ML19210F010
Person / Time
Site:	Vermont Yankee
Issue date:	12/10/1979
From:	Conway W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19210F007	List: ML19210F006 ML19210F010
References
LER-79-030-03L, LER-79-30-3L, NUDOCS 7912130385
Download: ML19210F010 (2)

Text

(7 77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 0 1 lV lT V l Y l S l 1 l@l 0 } 0 -l 0 0 0l 0l 0 -l 0l 0 25l@l 264 ] 1LICENSE 1l 'j 1 @l57 CAT 68 @

7 8 3 LICENSEE COCE 14 15 LICENSE NUMBER T /PE Jo CON'T l1 l0 l7 l9 l@l1 2REPORT l1 0 17 19 @

0 7

1 8

"'[RCe O

60 l L l@l 61 0 l 5DOCKETl 0 l NUMBER 0 l 0 l 2 l 768l1 @l1 63 l1 EVENT DATE 74 75 DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l

o 2 l o 3 l See attached sheet I o 4 I l

I o s i O s l o 7 I I O 8 l 80 7 8 9 SYSTEV CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUSCODE SUSCODE 7

O 9 8

lIl B lh l A lh lF lh 9 to 11 12 13 Il Nl Sl Tl Rl Ulh lT h lZ lh 18 19 20 SEQUENTI AL OCCURAENCE R E PO'4 T REVISION EVENT YEAR REPORT NO. CODE TY 3E NO.

LER RO h ,,AEPg l7 l9 l l_l l0 l3 l0 l/l l0l3 lL l l-l 3"

0l

_ 21 22 23 24 26 27 28 29 30 31 TAK N AC ON ON PLANT ET HOURS S8 IT FOR b 8. SUPPLIE MANUFAC UAER l33B l@lH l@ l35Z l@ Zl@ 0 0l 0} 0l Yl@ lYl@ l43N l@ l44R l 2 l 9 l 047l@

34 36 31 40 41 42 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 1 0 l li li l The packing leak was repaired, the reference les refilled, and the instruments i 2 l returned to operation. A similar occurrence was reported as RO 79-24.

t 3 l 1 4 l 7 8 9 80 STA S *. POWE R OTHER STATUS IS O RY DISCOVERY DESCRIPTION i1 5 dh 1 l0 0 lh! NA l l A lhl Operator observation l ACTIVITY CO TENT AELEASED OF RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7

1 6 4 3 O h dh 10 11 NA 44 45 NA 80 l

PERSONNEL EXPOSURES CESCRIPTION w NUYBER TYPE 1 7 l0l0l0lhlZlhl NA l PERSONNE L INJLRIES NUY8ER DESCRIPTION li l - 8l 3l O ! 0 l 0 lhl 7 11 12 NA 80 LOSS OF OR D AM AGE TO F ACILITY 1 9 TYPE dh C E SCRIPTION NA 7912130 , Ek l d 3 10 80 c

CSvE DESCRIPTION 7

2 0 s 9 hl to N\

sa sa l lllllllIlI!!

s2 ;

NAME OF PREPARER

4. F. Conwav PHONE: 802-257-7711 2,

VTVYS1 05000271 LER 79-30/3L EVENT DESCRIPTION AND PROBABLE CONSEQUENCES During steady state operation, Control Room personnel observed an increasing trend in indicated torus water level on Control Room Indicators LI 16-19-46A/B. Wheg an indicated level of 1.26' was reached (corres-ponding to 70,000 ft ) an orderly shutdown was initiated as necessitated by Technical Specification 3.7.A.8.

Upon investigation, it was determined that a bypass valve for the torus level transmitters had developed a packing leak thereby slowly draining the transmitters common reference leg and causing the erroneous readings. Technical Specification 3.2.G requires this post-accident in-strumentation be operable during reactor operation. At no time was the torus water inventory out of specification. Since this indication was restored within the limiting 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of Tech. Spec. Table 3.2.6, the plant shutdown was terminated and power operation was continued. Based on the above, the potential consequences to the health and safety of the public were minimal.

1552 239