ML20065G951

Special Rept:On 900830,alert Declaration Received Following Inadvertent Carbon Dioxide Discharge.Normal & Emergency Portable Ventilation Established to Purge Affected Areas. Repairs on Valve Scheduled

ML20065G951
Person / Time
Site:	Beaver Valley
Issue date:	10/15/1990
From:	Noonan T DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9010240273
Download: ML20065G951 (5)

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, Telephone (412) 393-6000

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ND3MNO:3048 '

' Stuppmgport PA 16077-0004 i

Beaver Valley Power Station, Unit No. 2 ,

Docket No.'50-412, License No. NPF-73  !

3 Soecial ReDort i

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', TUnited' States Nuclear Regulatory Commission- JI

, = Document Control Desk Washington, DC 20555'

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Gentlemen:

a .The ;following" Special Report is submitted detailing the 1 W

i recent . Alert ' Declaration that occurred at Beaver -Valley Unit ' 2 following an.' inadvertent-Carbon Dioxide discharge'.

1 DescriDtion of Event i f

' On t August' 3 0, '1990, post maintenance testing was performed on a carbon- dioxide . fire. ' protection - system. discharge timer.- The- ,

timer ~ is in the control circuit of - the fire protection system

that protectsJthe Beaver Valley Unit Two cable vault areas. The 1 6

<timerJhad been-replaced after surveillance testing had s

' identified it ' as failing to initiate .the proper timed sequ'ence

'* =of carbon l' dioxide discharge.

lDuring' .the test, ' timer operation would be initiated: to confirm ,

Eproperftimer operation. An actual carbon idioxide f discharge < wasi l "toibenprevented by - manually isolating that portion = of : the - fire l

• .  : protection' system affected by the timer during'the test. ~~A fire watch was stationed throughoutlthe affected area while-the test- .

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. was'iinL progress. The crew: performing the test. consisted of an p"1

. . operations supervisor, two' auxiliary operators, andHan- ..

' Instrumentation and. Control (I&C) technician. The operations 4 y' supervis'or: had been ' assigned to coordinate all fire ' protection ')

Hf 7 system J testing and had ' performed the test during- past required.

Tsurveillances. .The supervisor conducted a pre-test briefing' ,

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withF the; operators',

the' fire watch, - ' the , I&c. tech, an-I&C L,

g  : supervisor, ; :and ' a fire protection, engineer.(

Items discussed 1 N 4

included' the' nature 'of the test, expected l audio and. visual. ~

1

' alarms . -expected system response,

, and required restoration )

1;. @ < isteps., T h e '. c o n t r o l room was. notified Lof the . same. It was "f

- inotedj f aat, ialthough' unexpected,, the scent of the oil =of 't

.O g p wintergreen 1 odorant in - the carbon dioxide system would be an-Lindicator'of:a problem:and require the use of Self Contained

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' MRC-ND3MNO;3048- s Page 2 Breathing. Apparatus (SCBAs) and evacuation of personnel to an ,

area of higher- elevation. '

Since the carbon dioxide was - not '

expected to discharge, the operators were told to be aware;of any j l tsound of. gas in the piping going to the affected' zone. -A general page ' announcement was made to alert - the plant personnel' of L the i initiation of the test, as was required by the test procedure'.  ;

The fire protection ' system being tested consisted of a carbon dioxide tank.with a master actuation valve and a manual isolation

~

13 valve on.its discharge. Down stream .of the manual- isolation valve,- the system flowpath split into several zones of fire  !

protection a r e a s'. Each zone had its own automatic isolation i valve and actuation' timer. -On a fire protection signal from~any zone, the master actuation valve at the tank is opened ~

automatically. The zone -timer opens its actuation . valve after a 60 second time delay. If- only one zone has a fire protection signal, carbon dioxide will only be discharged to that zone, ,

although the other zones will have carbon dioxide pressure up to l their automatic zone isolation valves.

During the test, the carbon dioxide tank was . isolated', -in accordance with the- procedure, using the manual isolation' valve at the tank. The -carbon dioxide piping was then vented in order : i to provide a 'flowpath for any gas trapped downstream of the tank i manual isolation valve, and upstream of the automatic zone isolation . valve. Venting this piping -prevented trapped carbon dioxide from discharging : into the affected zones. The test then proceeded to initiate a demand' signal' f or carbon dioxide discharge .using' the manual actuation pushbutton. This would' 1 actuate- the ' timer and open the automatic zone isolation valve in series with and downstream of the tank manual isolation valve..

During normal system. ' operation, this action' would cause _ carbon I? dioxide to be discharged into the cable vault areas.

m '

Following pushbutton operation, a pre-discharge horn and flashing red alarm light was actuated, for sixty seconds', as woul_d - normally be expected. After this time delay, the zone .

isolation valve opened. It was then noted that there was .the i sound of' gas' rushing through,the zone piping. It was also noted that frost began-to form on the main gas line indicating ' carbon .

dioxide ' leaking through' the tank isolation valve.. .The control l p . room was notified of a carbon dioxide discharge by the operations

< g' supervisor located outside of the affected zone. The station

-standby alarm was sounded and the emergency squad was assembled. l Members of the- emergency squad donned SCBA- masks, obtained' O portable oxygen monitors, and were dispatched to perform a search 1

% of the affected area. . The fire watch had evacuated.to a higher. l

' elevation.in an unaffected building. A plant par announcement i

@ , was made warning of the gas discharge and ev m ation of the 1 L, affected zones in' addition to areas adjacent to and below the  !

T affected zone. The operators verified the fire watch to be in a i l

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.'sa f e = 1ocation , and continued .to search af fected ' areas.

No '

personnel 'were found to have been affected by the gas discharge. i No equipment-in the area was adversely affected by.the gas. The main isolation valve was' checked to be closed and tightened'.. The carbon dioxide signal.was reset, closing the zone isolation valve

.and , terminating- the gas release. It was estimated that three

' tons of carbon. dioxide' gas had been released to the east ~and west cable vault areas over a period of approximately 4 minutes.- ,

,The cable. vault oxygen concentration was measured. by the -

emergency squad . to be 15%. An alert was declared at 1110- hours '

fdue ta a gas release resulting in oxygen concentrations .in' an area that were less than the Occupation . Safety and Health '

Administration (OSHA) standard of ,16%- by volume -

that !1evel necessary to ' support life. Normal and emergency ' portable -

ventilation was- established to purge the carbon dioxide-from the I affected areas. The emergency squad continued to survey the L, zones for' oxygen and communicated such to the control room.

Security was used to restrict access to the oxygen , deficient '

s areas. .

L once all areas 'were verified greater than 20% oxygen, normal  ;'

p access was - ' again permitted. Following a conference with all H Ecutside agencies to discuss the plant status, the-alert was then terminated at 1311 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.988355e-4 months <br />.

b The- timer, -which had been the focus of the test, failed' to L . perform as ; required. It was . replaced, and successfully tested the following-day. The zone valve which opens on a demand signalf -l was , disabled by mechanically isolating the valve's pilot valve,'

l and lifting the : actuating solenoid leads. This provided double-  ;

isolation to' compensate L for the leak' through the manual tank 4 isolation valve.. A maintenance work request was generated to -

E inspect and repair the manual isolation ~ valve.

The affected-L carbon dioxide tank has been drained and ' an alternate tank:

! aligned to supply the fire protection system. Repairs on the valve 1have been scheduled.

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DC/cj .- ,

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l Very truly yours, I

T. P. Noonan  !

, General Manager m Nuclear Operation

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N' October 15, 1990

' . ND3MNO 3048 Page141

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cc: i Mr. JP, T. Martin, Regional Administrator

United' States Nuclear Regulatory Commission Region 1 .

s' 475 Allendale Road i King.,of-Prussia, PA 19406 C.!A.;Roteck, Ohio Edison 76 S. Main-Street Akron, OH 44308 Mr. A.fDeAgazio,c.BVPS Licensing Project Manager United States Nuclear Regulatory Commission Washington,1DC 20555 J. Beall, Nuclear Regulatory-Commission, BVPS Senior Resident Inspector I

Larry Beck .

i Cleveland Electric ~t 6200 Oak Tree Blvd. '

Independence, Ohio 44101 '

INPO Records Center Suite 1500' -j' 1100 Circle'75 Parkway g Atlanta, GA' 30339 LG. E. Muckle, ,

Factory Mutual Engineering, Pittsburgh 31 Parkway Center Room 217 4

~Pittsburgh,.PA 15220 ,

Mr. J.-.N.LSteinmetz,: Operating PlantiProjects Manager -

d Mid' Atlantic Area ,

p Westinghouse ElectricLCorporation  :

Energy Systems. Service Division <

Box 355 M Pittsburgh, PA -15230 4 American Nuclear. Insurers j l , c/o Dottie Sherman, ANI Library The Exchange Suite 245 f , 270 Farmington Avenue Farmington, CT 06032-

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j .Mr. Richard Janati d Department of Environmental Resources P. O. Box 2063: ' '

16th Floor, Fulton Building p: ' >Harrisburg, PA 17120 .l l- '

' Director, Safety Evaluation & Control i Virginia-Electric & Power Co.

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.P.O. Box 26666 -

One-James. River Plaza

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Richmond, VA 23261 7 3 e i .- ~ _ _ _ _ _ _ . . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _

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' - 1Octobsr'15,c1990 ~

'. Ji .ND3MNO:3048 Page 5;

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.W. Hartley, Management' Analysis company.

112671 High-Bluff Drive San Diego,:CA. 92130-2025 i

J. M. ' Riddle =

NUS Operating Service Corporation Park West II.

Cliff Mine Road

_Pittsburgh; PA 15275 L

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