ML20085L701

AO 50-267/75/5:on 750127,gas Vacuum Tank Rupture Disc Ruptured,Releasing Small Quantity of Gas.Caused by Inadequate Procedures.Procedure Rewritten

ML20085L701
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/17/1975
From:	Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085L694	List: ML20085L691 ML20085L698 ML20085L701
References
AO-50-267-75-5, NUDOCS 8311020354
Download: ML20085L701 (9)

Text

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o o public service company ce ocaemde P. O. Box 361, Platteville, Colorado 80651 i;,.

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, .. '( .'.;, /('. .A February 17, 1975

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1. Qiig;M Mr. E. Morris Howard, Director Region IV, Office of Inspection and Enforcement 611 Ryan Plaza Drive - Suite 1000 Arlington, Texas 76012 Ref: Facility Operating License No. DPR-34 D,ocket No. 50-267

Dear Mr. Howard:

Enclosed please find a copy of Abnormal Occurrence report No.

50-267/75/5, submitted per the requirements of the Technical Specifications.

Very truly yours,

&k$wN Frederic E. Swart Superintendent Nuclear Production Public Service Company of Colorado FES:ll cc: Mr. Angelo Giambusso e

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8311020354 760621 l PDR ADOCK 05000267 S PDR COPY S ION ~^

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REPORT DATE:

o Februa ry 4,_,1_975 O

ABNORMAL OCCURRENCE 00CURRENCE DATE: January 27, 1975 FORT ST. VRATN NUCLEAR CENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361

'PLATTEVILLE, COLORADO 80651 k.

REPORT No. 50-267/75/5 Final IDENTIFICATION OF OCCURRENCE:

A gas waste vacuum tank rupture disc ruptured releasing a small quantity of gas.

This is identified as an Abnormal Occurrence, per Technical Specification 3 definition 2.1.c.

CONDITIONS PRIOR TO OCCURRENCE: Steady State Power

_ Routine Shutdown Hot Shutdown Routine Load Change X Ccid Chutdown Orhar (crecify)

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

Power RTR MWth Elect. O MWe Secondary Coolant Pressure 1000 psig

, . Temperature 210 '*F (Feedwater on pre-Flow 180,000 (boiler recirculation) .

1. /hr.

I Primary Coolant Pressure 97 psia Temperature 255 *F Core Inlet t- .

210 *F Core Outlet Flow 10% on "C" Cire. #/h'r, s

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O r=ce 2 DE'SCRIPTION OF '

OCCURRENCE:

Upon completion of regeneration of train "A" Low Temperature Adsorber, the regeneration system was to be purged with cican helium, the purge gas is purged to the Gas Waste Vacuum tank.

p After purging, the regeneration system is brought up to 88 psig to perform the next step in the regeneration procedure.

When the regeneration compressor C-2302 was started, PDV-2359 went wide open, PV-2352 went wide open due to high pressure ( =150 psig)"A", that from was in the low temperature absorber section of purification train the helium storage system.

The rupture discs on the Gas Waste Vacuum tank are set for 5 psig. When *

• the high pressure vss introduced into the gas waste vacuum tank the rupture disc was ruptured.

Upon notification by the Reactor Operator that the rupture disc had ruptured it was isolated and the standby rupture disc was placed in service.

APPARENT CAUSE f OF OCCURRENCE: Design Unusual Service Cond.

Including Environ.

Mannfacenre ,

,_,-Component F ilur:

Installation /Const. Other (specify)

X Operator X Procedure The low temperature adsorber was purged according to the SOP. The procedure did not specifically state that PDV-2359 should have been in manual and in the wide open position and PV-2352 should have been in manual fully closed before the regeneration compressor C-2302 was started. This proper valvo lineup would have equalized pressures throughout the regeneration system and would not have allowed high pressure.to be introduced in the Gas .

Waste Vacuum tank T-6301.

ANALYSIS OF

• OCCURRENCE: - -

Release from the ruptured disc was about 3 minutes at - 100 ACFM. No increase in activity was detcetabic on the stack radiation monitors -

(RT-7324-1, RT-7324-2, and RT-7325-1). Subsequent analysis of gas in the gas waste-system for release No. 77 showed no measurabic gamma activity.

Allowable release rate for tritium on release No. 77 on February 3,1975, -

.j was 3.9 (10-7) ACFM. .

O l

l

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Page 3 l

^

l CORRECTIVE ACTION:

The SOP was rewritten giving specific valve positions when purging the components in the regeneration section. This situation was reviewed

- with the operators. The need to be aware of potential problems, even

. though not directly. spelled out in the SOP, was stressed, p FAILURE DATA /

SIMILIAR REPORTED OCCURRENCES:

Abnormal Occurrences 50-267/74/21 and 50-267/74/22 both involved rupture

.of the rupture disc but the causes are unrelated. No. 74/21 was due to a release of gas from the gas waste compressor relief valves and No. 74/22 was due to a pressure setting error in the operating procedure.

PROGRAMMATIC IMPACT:

None CODE IMPACT:

Nonet I

APPROVED: 9 RECOMMENDED: ,

[LMM ,,h_ , . .

~

_f H.LarryBrpy ) jrederic E. Swart

. Superintendent-Operations $uperintendent Nuclear Production Fort St. Vrain Nucicar Public Service Company Cencrating Station of Colorado e

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, REPORT,DATE:p{

g February 4,1975 V ABNORMAL OCCURRENCE e- ,

. OCCURRENCE DATE: January 27, 1975 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 0, , g' REPORT No. 50-267/75/5

NJi

,--- s Final ','

.s'

.._n A IDENTIFICATION OF OCCURRENCE:

A gas waste vacuum tank rupture disc ruptured releasing a small quantity of . <

gas.

-This is identified as an Abnormal Occurrence, per Technical Specification definition 2.1.c.

CONDITIONS PRIOR TO OCCURRENCE: Steady State Power _ Routine Shutdown Hot Shutdown Routine Load Change X Cold Shutdown other (specify)

Refueling Shutdotm Routine Startup The major plant parameters at the time of the event were as follows:

Power RTR MWth Elect. -

0 MWe Secondary Coolant Pressure .i1000 psig Temperature '210 *F (Feedwater on pre--

Flow 180,000 (boiler recirculation)-

1. /hr.

Primary Coolant Pressure 97 psia

.i

. Temperature 255 *F Core Inlet

• 210 *F Core Outlet-Flow 10% on "C" Cire.- f/hr.

! i gb 62 .l.882

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Pags 2

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l DESCRIPTION OF OCCURRENCE: .

Upon completion of regeneration of train "A" Low Temperature Adsorber,

)

the regeneration system was to be purged with clean helium, the purge gas is purged to the Gas Waste Vacuum tank.

p Af ter purging, the regeneration system is brought up to 88 psig to perform the next step in the regeneration procedure.

When the regeneration compressor C-2302 was started, PDV-2359 vent wide open, PV-2352 vent wide open due to high pressure ( =150 psig)"A", that was from in the low temperature absorber section of purification train the helium storage system.

The rupture discs on the Gas Waste Vacuum tank are set for 5 psig. When the high pressure was introduced into the gas waste vacuum tank the rupture disc was ruptured.

Upon notification by the Reactor Operator that the rupture disc had ruptured it was isolated and the standby rupture disc was placed in service.

APPARENT CAUSE Design Unusual Service Cond.

OF OCCURRENCE: Including Environ.

Manufacture Component Failure Installation /Const. Other (specify) 4 X Operator X Procedure The low temperature adsorber was purged according to the SOP. The procedure did not specifically state that PDV-2359 should have been in manual and in:

the wide open position and PV-2352 should have been in manual fully closed before the regeneration compressor C-2302 was started. This proper valve lineup would have equalized pressures throughout the regeneration system and would not have allowed high pressure to be introduced in the Gas Waste Vacuum tank T-6301.

ANALYSIS OF OCCURRENCE: .

Release from the ruptured disc was-about 3 minutes at - 100 ACFM. No increase 'in activity was detect'able on the stack radiation monitors (RT-7324-1, RT-7324-2, and RT-7325-1). Subsequent analysis of_ gas in the gas waste system for release No. 77 showed no measurable gamma activity.

Allowable release rate for tritium on release No. 77 on February 3,1975, was 3.9 (10-7) ACFM.

4 9 n

• O

,g

10

~

O~ D Pago 3 .

, )

CORRECTIVE ACTION:

The S0P was rewritten giving specific valve positions when purging the components in the regeneration section. This situation was revie..cd with the operators. The need to be aware of potential problems, even p

though not directly spelled out in the SOP, was stressed.

FAILURE DATA /

SIMILIAR REPORTED OCCURRENCES:

Abnormal Occurrences 50-267/74/21 and 50-267/74/22No. both involved rupture 74/21 was due to of the rupture disc but the causes are unrelated.

a release of gas from the gas waste compressor relief valves and No. 74/22 was due to a pressure setting error in the operating procedure. .

PROGRA>D!ATIC IMPACT:

None CODE IMPACT:

None' i

APPROVED: 9 RECOFDIENDED:

,.e te 8bbW Am ,,i ~ "

H. Larry BPey j ,'

pederic E. Svart

$uperintendent Nuclear Production Superintendent-Operations Public Service Company Fort St. Vrain Nualear of Colorado 2 Generating Station .

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