ML20065G951
| 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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s Telephone (412) 393-6000 October 15, 1990'
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.eo no.4 ND3MNO:3048 c.
' Stuppmgport PA 16077-0004 i
Beaver Valley Power Station, Unit No. 2 Docket No.'50-412, License No. NPF-73 Soecial ReDort i
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TUnited' States Nuclear Regulatory Commission-JI
= Document Control Desk Washington, DC 20555'
'i Gentlemen:
1 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-
. was'iinL progress.
The crew: performing the test. consisted of an b
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' W
- withF the; operators',
- the' fire watch, - ' the, I&c. tech, an-I&C L,
- supervisor, ; :and ' a fire protection, engineer.(
Items discussed g
N
- included' the' nature 'of the test, expected l audio and. visual.
4
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1
' alarms. -expected system response, and required restoration
)
1 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 wintergreen 1 odorant in - the carbon dioxide system would be an-p Lindicator'of:a problem:and require the use of Self Contained g
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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
~
1 valve on.its discharge.
Down stream.of the manual-isolation 3
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 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 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 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.
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.
elevation.in an unaffected building.
A plant par announcement 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 9
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NRCJ 1*
8D3MNO:3048.
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.'sa f e = 1ocation,
and continued
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.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 that !1evel Administration (OSHA) standard of,16%- by volume 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 areas.
s 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.
'i DC/cj.-
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l Very truly yours, I
T.
P. Noonan General Manager Nuclear Operation m
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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 Atlanta, GA' 30339 g
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
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Farmington, CT 06032-1 0
.Mr. Richard Janati d
j Department of Environmental Resources P.
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Box 2063:
16th Floor, Fulton Building
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>Harrisburg, PA 17120 l-
' Director, Safety Evaluation & Control i
Virginia-Electric & Power Co.
.P.O.
Box 26666 m
One-James. River Plaza
",o Richmond, VA 23261
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- 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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