ML20002A782

Forwards LER 80-057/03L-0

ML20002A782
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/31/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20002A783	List: ML20002A782 ML20002A785
References
P-80384, NUDOCS 8011210541
Download: ML20002A782 (5)

Text

_

i public Lvice Company e Collende

'$ ) 16805 ROAD 19%

iL.s PLATTEVILLE, COLOR ADO 80651 October 31, 1980 Fort St. Vrain

. Unit No. 1

'P-80384 _.

, M a

x

_ k W

b,5

.B  ;

Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commission 7,;] h,  :

Region IV y m

^

Office of Inspection and Enforcement g eq 611 Ryan Plaza Drive o Suite 1000 Arlington, Texas 76012

Reference:

Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No.~50-267/

80-57, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report f or Reportable Occurrence Report No. . 50-267/80-57.-

Very truly yours, Don War ourg Manager Nuclear Production DW/cis Enclosure cc: Director, MIPC 80112tosry, g,

L... e OCCtJRRENCE REPORT SISTRIBUTION Number of Cootes (P Letter)

De pa r t me nt o f Ener gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 San Francisco Operatione Of fics Atta California Patent Group 1 1333 Broadway Cakland. California 94612 Dg pa r tmen t o f Ene rgy - - - - - - - - - - - - - - - -------------- 1 (P Letter)

Of fice of Nuclear Engineering Programe j Washington, D.C. 20545 De p a r t men t e t Ene r gy - - - - - - - - - ' - - - - - - - - - - - - - - - - - - - - - 1 (P Letter) ,

tir Glen A. Newby. Chief WTR Branch '

Division of Nuclear Power Development l Mail Station 5-107 Washington, D.C. 20545 .

De pa r tme nt o f Ene r gy - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter)

Atta: - Senior Program Cooroinator -

P. O. Box 81325 San Diego. California 92138 Mr. Karl V. Seyfrit. Directer -------------------------

Region IV 'f 1 (Original of P Letter and Copy of LZR)

Of fice of Inspection and Enforcement Nuclear Regulatory Commission 611 Ryan Plaza Drive Suite 1000 Arlington. Texas 76012 i

Di re c t o r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter. LER)

Of fice of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr . Ri ch a rd Phe lp e - - ; - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (Original of F?LG Latter TSV. GA. Site plus Two Copies. One Rep resent ative Copy of P Letter, One Ceneral Atomic Company Copy of LER)

-P. O. Sox 126 Plattev111e, Colorade 80651 g

!!r . S ill Lava lse - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 (P Letter. LER)

Nuclear Safety Analysis Center 3412 itillview Avenue P. O. Box 10412 Palo Alto. California 94303 NRC Resident Site Inspector -------------------------- 1 (P Letter. LER) l l

I l

l-l

[

I'

, =e - - etw

REPORT DATE: October 31, 1980 REPORTABLE OCCURRENCE 80-57 ISSUE O OCCURRENCE DATE: October 4, 1980 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WEID COUNTY ROAD 191/2 PLATTEVILLE, COLORADO 80651 REP mT NO. 50-267/80-57/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

On October 4,1980, the plant was operated with PCRV pressure greater than penetration interspace pressure.

This constitutes operation in a degraded mode of LCO 4.2.7 c) and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT DESCRIPTION:

At 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br /> on October 4,1980, with the plant operating at approximately 7% thermal power, operations personnel received an alarm indicating low dif-ferential pressure between PCRV primary and secondary containment and, upon investigation, observed a problem with operation of the switch monitoring pressurization of the PCRV penetration interspaces. The switch (PS-11227) monitors the helium pressure from the purified helium header and helium storage system to the PCRV penetration interspaces, and is set to terminate pressurization of the interspaces on high pressure at 788 psig. Switch actuation on high pressure would serve to close HV-11250 (on the line from the helium storage system) and HV-1128 (on the line from the purified helium header).

During routine PCRV pump-up to replace helium losses, helium is admitted to the penetration interspaces via penetration pressurizing valve HV-11250 to maintain the interspaces at a higher pressure than the PCRV, as required by LCO 4.2.7 c) . Penetration interspace pressure is required to remain greater t.han PCRV pressure in order to maintain primary coolant integrity.

With this condition met, any primary seal leakage would consist of clean helium into the primary coolant. Secondary seal leakage, if any, would involve leakage of clean helium to the reactor building atmosphere.

On October 4,1980, during routine PCRV pressuri:ation, a problem developed with PS-11227 operation, and the switch actuated at a much lower pressure than the required 788 psig. This resulted in the closure of HV-11250 and HV-1128, thereby terminating pressurization of the penetration interspaces. Pump-up of the PCRV was continued, which resulted in PCRV pressure exceeding pene-tration interspace pressure, i l

l l

l

REPORTABLE OCCURRENCE 80-57 ISSUE O Page 2 of 3 EVENT DESCRIPTION: (Cont'd)

Immediately upon discovery of the LCO 4.2.7 degraded mode, PCRV pressuri-zation was terminated and an investigation was initiated to determine the cause. of PS-11227 operability problems. By 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> on October 4, the switch had been repaired and was back in service, and PCRV penetration inter-space pressure was once again higher than PCRV pressure.

CAUSE DESCRIPTION:

The pressure switch which monitors interspace penetration pressure is equipped with a Bourdon tube which expands as pressure increases and serves to actuate the switch mechanism at a preset value, thus terminating penetration pressur-ication. Investigation revealed that the linkage connecting the Bourdon tube to the switch mechraism was loose. As a result, the switch actuated at a pressure lower than the preset valve, which allowed PCRV. pressure to exceed penetration interspace pressure.

CORRECTIVE ACTION:

Corrective actions associated with this occurrence were as follows:

1. Upon observation that PCRV pressure was greater than penetration inter-space pressure, PCRV pump-up was terminated.

2. The loose linkage on the pressure switch was retightened, and the switch recalibrated per approved procedure.

3. Penetration interspace pressure was returned to a value higher than PCRV pressure.

No further corrective action is anticipated or required.

I l

i Or *

. .+

r REPORTABLE OCCURRENCE 80-57 ISSUE O Page 3 of 3 Prepared By: t[E h Cathy C. Alirsch

$4 Technical Services Technician Reviewed By: '

W. Gaiun echnical Services Supervisor Reviewed By: -

f Frank Mpthie Operations Manas r Approved By: M[M b fl N Don Warejnbourg ' /

Manager,# Nuclear Production t

i

. - - . . . . . ,