ML20086B123

AO 50-267/74-21A:on 741121,high Pressure in Gas Waste Vacuum Tank Lifted Relief Valve Allowing Release of 700 Scf Uncontaminated Gas.Caused by Procedural Error.Inlet Valve Seats Will Be Replaced & Interim Procedure Modified

ML20086B123
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/12/1975
From:	Rodgers W, Swart F PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20086B083	List: ML20086B079 ML20086B100 ML20086B107 ML20086B115 ML20086B123 ML20086B129
References
AO-267-74-21A, NUDOCS 8311170062
Download: ML20086B123 (3)

Text

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Februa 2, 1975

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FORT ST. V.ut!! ::t:Cf.rAR CC?;E:tATI':G STATIO' PUBLIC SE? NICE Cn"?.t!."i OF C01.0RADO P . O. !!OX 361 PLATTEVILLE, COLORADO A0651 . 4 REPORT I:0. 50-267/74/21-A Final -

ne':TIFICATIO:1 0F

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• y . n. *:y nn ?:ovenber 21, 1974, high pressure in the gas vaste vacuum tank ruptured

.: ru:iture disc and lif ted a relief valve allowinr. an unauthori=cd release of

.r pr. win.itelv 700 SCF of uncontaninated gas to the reactor buildinq ventilation -

vs:.n. This is identified as an abnornal occurrence per Technical Specifications

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CD:.**)I' !G::S PRIOR

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.y Steady State Power Routine ..htde.:n Hot Shutdown Routine Load Changg

'X Cold Shutdown '~ ' Other (specify)

- Refueling Shutdown Routine Startup The najor plant parameters at the time of the event were as follows:

Power PTR, U/A MJth ELECT, N/A Mfe Secondery. Coolant Pressure n/A psig Temperature n/3 *F Flow N/A #/hr.

' ~

Prinary Coolant Pressitre o psig ,

Tenperature 115 *F Core Inlet 135 *F Core Outlet -

. ,. Flow 0 #/hr. .

8311170062 760903 - g PDR ADOCK 05000267 - ,

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gau_

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r- %

> van 2

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O ...........,s.. ,y eg - :cr..

......-..- wrification rareacr1tien s*.'ste , to the. "A" 109

11.

c,t tn deein tha .hclite: -'f the re eneration of f.t. .ein ta: h, at the concInsion va=;t e rur; c tank was alarned. -

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. r :- .i'.ur%r, high prassure en " A" ' .t t " i" tanh 5ut the inlet valve ef f cetively sinittins of f t

r. .i :.'r e :'. rator fr~.2diatcl7 n':h chc.i to th.:

d !-

• o ' n'uit , f 11:1 to "li" s trre tanh h.9 heen h:'rflo , path of both nas vante cerprem;

('-l Tite remiltin:'. abrupt pressurc

b .ti char *e e: f' c dischar',e of the conpressor i. d snicty valve to bc

. :; i. - The i ro e in the vaettun tank caused the re ture dine an700 FCF of ras to M. v , r..icaning :

vent !!ation exhaust is nonitored and the e in "A" surne tank contents instru-,enSubsequest lab analysin o .

the p.as.

c$.ut e in count rete.

contained that no detectabic activity was present APPARr.::T CAUSE '

OF occlintrt:CE: Unusual Service Cond.

X _ Design _

Including Environ.

" Conponent Failurc -

Manufacture

_Other (specify)

Q

-- ' -- Installation /Const. ,

llX- Operator ' .. ,

Procedure

. _-X A':AT.YSIS OF .

ocrr:n-:cE:

..e tank have Icahed Peninn:

The isolation valves at the inlet to cach'nas vaste surgehandjack h on a valve .

in the past and a practice has been established to set t ein Icakace and release of unanal

. .9.aurine.

s.

a relcana fica the tank to preventThe handjack was set but not re 4 h tor 0;'erator :

A hold tag should have been placed on the handswitch to alert t e opera

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that the handjack on ItV-6336 was set closed. . . .

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1 Procedure: does not specifically list a" check of handjack renoval or a .

The valve list . -

test of valve operation. -

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CORRECTIVE ACTTON:

Design:

A Change Notice (#101) has becu issued to replace the seats in the inlet valves to the gas vante surge tanks with soft reatn. A gooil seat in these valves will uake the une of the handjack unnecessary.

Change Notlec #91 has been issued to change the wiring so etther 11V-6335 or HV-63% will always be open. The change provideo for a switch with a mid-position whern both valves are open.

Operator:

Operators have been issued a mt mo t o place a "H01.D" tag on the tank scicetor switch when a bandjack is set on either valve. .

Procedure:

The System Operating Procedure valve list has been modified to call for handjack removal after the discharge is complete and includes a test

• of valve operation. Thin step will be removed after the soft sent valves at the tank inlet are installed and proven to be Icak free.

FATI.URE DATA /

SIMIIAR REI'ORTED OCCURRENCES:

Nonc PROGRA*fMATIC IMPACT:

None CODE IMPACT: s None Submitted by: Approved by:

W. Duanc Rodgers /> ._

rederic E. Swart Superintendent Nucicar Production Operations Supervisor Public Service Company Fort St. Vraln Nuclear Cencrating Station of Colorado s

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