ML20086B446

AO 50-267/74-11A:on 740625,gas Waste Release 50 Took Excessive Length of Time & Flow Continued from Receiver Outlet Valve B When Receiver a Empty.Caused by Defective Isolation Valve B.Second Isolation Valve Will Be Installed

ML20086B446
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/22/1974
From:	Brey H, Rodgers W PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20086B449	List: ML20086B446 ML20086B452 ML20086B453 ML20086B459
References
NUDOCS 8311170228
Download: ML20086B446 (3)

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.. g P. O. Box 361, Platteville, Colorado 80651 October 22, 1974 cp,i. ',

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[ g O c t ,*; 2 : n lir. 2. Iforria Itcuard , Dircetor mh

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Directorate of Reguintory Operations ei . . J

'r Region IV, U';A!:C 19395 Ucst Colfax, Rcon 200 DU' ' . 'f ,4-Denver, Colorado 80215  % 4. t.) ! \ 'c(1,1, j/

RFF: Facility Operatin?, Licensa

?ie. DP?.-34 Docket lio. 50-267

Dear Ifr.1:

otrard:

Eaclosed pleace find a ce;)y of Abnoraal Occurrence Report IIo.

50-267/74/lla, Final, culnitted per the requirennats of the Technical Specifications.

Very twly yours,

11. Larry Brcy Superintendent-0perations Fort St. Vrain : nclear Generating Station 1[LB:il cc: !!r. Angelo Ginubusco 9311170228 741022 PDR ADOCK 05000267 g PDR 11000 sz.a&')

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! COPY SWI' REGION m s

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DATEi Octobc- y O S., 1974 'NOIU!AL OCCURRENCE FORT ST. VRAIN NUCLFAR CENERATING STATION ~

PUBLIC SERVICE CO:!PANY OF COLORADO .

P. O. BOX 361 .

PIATTEVILLE, COLORADO 80651 .

REPORT NO. 50-267/74/lla -

FINAL -

1DENTIFICATIO:I OP OCCURRENCE: -

- ~

The following is considered an Abnormal Occurrence under definition of .<

2.1 e of the Technical Specifications.

On 6/25/74 under gas vaste release number 50 it was noted that the release took an excessive length of time and when the A receiver was empty flow continued from a leak through the B receiver outlet valve.

CONDITIONS PRIOR TO OCCURRENCE: Steady State Power Routine Shutdown

• n:

Hot Shutdown Routine Load Change Cold Chutdoun X Other - (specif y)

Refueling Shutdown Prior to low power Routine Startup physics tests A-9 The major plant parameterr, at the time of the event were as follows:

Power PTR, N/A MWth ELECT, N/A MWc Secondary Coolant Pressure n/A psig Temperaturc N/A 'F Flow N/A f/hr. .

_ Primary Coolant Pressure 0 ~psig Temperature 135 'F Core Inlet 335 ~*F Core Outlet

/ ') - Flev , O f/hr.- , .

9 4

1 e

o o Page 2

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Df;CHIPTION OF OCCUn!!Er.qP:

~ On 6/25/74 gas vaste release number 50 from the A receiver was started c at 0100 and this receiver was not empty until 0045 on 6/28/74. The .

72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period is too long for a rcIcase of the tank volume at the controlled rate of 15 acfm. With the A receiver empty and isolated a flow of 4 acim was indicated on FT-6351 flow transmitter. This indicated .

, a lenhage from the B receiver. Plant troubic report 6-395 was written on the valve leakage. Tank analysis showed no radioactive material was released.

APPARENT CAUSE '

_OF OCCURRENCE: Design Unusual Service Cond.

1 Including Environ.

1 Manufacture 'X Component Failure Installation / Other (specify)

Const. '

~

Operator Procedurc 1

On 7/3/74 the B gas waste receiver outlet isolation valve was dismantled and it:was found to be defective, causing the Icakage. .

i ANALYSIS OF

_0CCURRENCE: -

E Analysis of the system shows that the valve leakage could.not be' determined, using the Systcm Operating Procedure .as-uritten, -until . the "A". receiver was 1

empty. No radioactive material was present in the B receiver.

CORRECTIVE ACTION:

1 A second isolation valve vill he added to each gas vaste rccciver outlet with a vent valve from the innerspace which vents to the vacuum tank.

This will assure. that no gas can.lcak from a tank to the vent system.

A change in SOP-63 will assure that. FT-6351 shows no flow prior to the start of the discharge.

1 New valves have been received and will be installed shortly.

j

' FAILURE DATA /SIMILAR REPORTED OCCURRENCES t .

Nonc ,

4 .

, PROGRAMMATIC IMPACT h

No programmatic 3mpact expected.

CODE IMPACT ,

a g None

( t ,' -

2, .

b h W. Duanc Rodgers, operations Supv.

H.Larryurcy{ supt. o operations y # y- ,. -,,.-m -

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