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: 05000267/LER-1974-021, :on 741121,high Pressure in Gas Waste Vacuum Tank Ruptured Disc & Lifted Relief Valve Allowing Unexpected Release of 700 Scf Waste Gas.Caused by Loss of Flowpath. Valves Replaced W/O Handjack ML20086B079 ML20086B100 ML20086B107 ML20086B115 ML20086B123 ML20086B129
References
AO-267-74-21A, NUDOCS 8311170062
Download: ML20086B123 (3)

Text

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Februa 2, 1975 Ct v 10rdtA1. OCCUR.Rff;CE

.. L r,:" guTE: __t1/21/74 O

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

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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

1. /hr.

~

Prinary Coolant Pressitre o

psig Tenperature 115

• F Core Inlet 135

• F Core Outlet Flow 0

1. /hr.

8311170062 760903 g

PDR ADOCK 05000267 S

PDR

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gau_

2

van 2 r- %

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wrification rareacr1tien s*.'ste, to the.

11.

c,t tn deein tha.hclite:

-'f the re eneration of "A" 109 the concInsion va=;t e rur; c tank was alarned.

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f.t..ein ta: h, at

" A" '.t t the inlet valve

.i'.ur%r, high prassure en

" i" tanh 5ut

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

ef f cetively sinittins of f

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t d !-

• o ' n'uit,

f to "li" s trre tanh h.9 heen h:'rflo, path of both nas vante cerprem;

('-l 11:1 Tite remiltin:'. abrupt pressurc

.ti char *e e: f' c dischar',e of the conpressor i.

d snicty valve to bc

b i ro e in the vaettun tank caused the re ture dine an700 FCF of ras to The

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M. v, r..icaning :

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

in the p.as.

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 The isolation valves at the inlet to cach'nas vaste surgehandjack on a valve Peninn:

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

. urine. a relcana fica the tank to preventThe handjack was set but not r 9.a s.

h tor A hold tag should have been placed on the handswitch to alert t e opera 4

0;'erator :

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the handjack on ItV-6336 was set closed.

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that l

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

i Procedure:

1 The valve list test of valve operation.

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o Page 3 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:

/>

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

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