05000244/LER-1992-001, :on 920105,containment Ventilation Isolation Occurred Due to Actuation Signal from Containment Particulate Radiation Monitor.Cause Is Unknown.Cvi Sys Returned to pre-event Status

:on 920105,containment Ventilation Isolation Occurred Due to Actuation Signal from Containment Particulate Radiation Monitor.Cause Is Unknown.Cvi Sys Returned to pre-event Status

ML20092C126
Person / Time
Site:	Ginna
Issue date:	02/04/1992
From:	Backus W, Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-001, LER-92-1, NUDOCS 9202110280
Download: ML20092C126 (8)

LER-1992-001, on 920105,containment Ventilation Isolation Occurred Due to Actuation Signal from Containment Particulate Radiation Monitor.Cause Is Unknown.Cvi Sys Returned to pre-event Status

Event date:
Report date:
2441992001R00 - NRC Website

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<U.S.LNuclea'rTRegulatory Commission Document ~ Control Desk

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Subject

1 LER192-001, Failure-of Containment Radiation' Monitor-3 EDue tom Unknown: Cause, Causes Containment Ventilation Isolation (i.e. ESF Actuation)_.

R.E.'Ginna Nuclear Power Plant-Docket No.-.50-244

- In accordance with 10CFR50.73, Licensee Event Report System,

.-item 1 (a) (2) (iv), _- which-requires a report of,- "any event or

. condition - that1resulted -in manual-- or automatic = actuation of any.

Engineered: Safety Feature.-(ESF),. including-the Reactor Protection

System (RPS)" j.- the -attached - Event Report LER 92-001 is~hereby i

submitted.

=This. event has in no way af fected ' the public's health and Lsafety.-

very truly yours, i

Robert C.

Mecredy t

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U.S.LNuclear. Regulatory Commission

- RegioniI-475 Allendale. Road W

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.Ginna;USNRC Senior Resident Inspector

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n On January 5, 1992 at approximately 0240 EST, with the reactor at approximately 98% full power, a containment ventilation isolation occurred due to an actuation signal from the containment particu-late radiation-monitor (R-11).

- All containment isolation valves that were open, closed as designed.

i-l Immediate operator action was to perform the applicable alarm i

. response procedures actions.

This included verifying automatic l

actions, determining the cause of the containment ventilation isolation, and making appropriate notifications.

l The immediate cause of the event was determined to be the failure-l of R-11.

l Corrective action taken was to return the containment ventilation isolation system to pre-event normal status, sequentially followed by a troubleshooting effort by the Instrument and Control Depart-ment, and then changeout of the R-11 drawer with a qualified

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Further investigation to determine the root cause is l

continuing.

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PRE-EVFNT PI. ANT CONDITIONS The plant was at approximately 98% steady state reactor power with no major activities in progress.

II.

DESCRIPTION OF EVE}{T A.

DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCFE:

o Januury 5, 1992, 0240 EST:

Event date and time, o

January 5,

1992, 0240 EST:

Discovery date and

time, o

January 5,1992, 0252 EST: Control Room operators restore R-11 (Containment Particulate Radiation Monitor and reset containment ventilation isolation).

D.

EVENT:

On January 5,

1992 at approximately 0240 EST, with the reactor at approximately 98%

full power, the following control board alarms were roccived, E-16 (RMS Process Monitor High Activity) and A-25 (Contain-ment Ventilation Isolation).

The Control Room operators, responding to the above alarms, observed that R-11 (Containment Particulate Radiation Monitor) had the light indicating failure illuminated.

The Control Room operators immediately referred to alarm response procedures AR-A-25 and AR-RMS, and verified that all containment ventilation isolation valves that were open, closed as designed and performed the applicable actions of the alarm response procedures.

Subsequently, at approximately 0242

EST, Control Board alarm E-20 (CNMT Or Plant Vent Rad Mon Pump Trip) was received.

This alarm was due to the trip of the containment radiation monitor pump and isolation of the containment valves to and from the pump.

The Control Room operators also verified that the other containment process radiation monitors were reading normal prior to the radiation monitor pump trip.

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R.E. Ginna Nuclear Ptner Plant o 15 i o l o I o 12 $ t 4 92 0 10 ! 1 -0l0 0 13 or 0 17 After the above immediate actions were completed, the Control Room operators addressed plant Technical Specifications and declared R-11 inoperable.

At approximately 0252

EST, January 5,

1992, the Control Room operators reset R-11 by cycling its AC power supply off and on, reset the containment ventilation isolation

signal, and restarted the containment radiation monitor pump.

All containment process radiation monitor readings returned to approximately pre-event values, indicating that R-11 was now operating properly.

Subsequently, av 0324 EST, the Control Room operators performed per. iodic test procedure PT-17.2 (Process Radiation Monitore R-R-22 Iodine Monitors R-10A and R-10B) on R-11 11 only and demonstrated that

'R-11 was operating as required.

C.

INOPERABLE STRUCTURES, COMPONENTS, OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:

None.

D.

OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED

With the containment ventilation isolation, the following major components were isolated:

o R-10A, Containment Iodine RMS Monitor o

R-11, Containment Particulate RMS Monitor o

R-12, Containment Gas RMS Monitor E.

NETHOD OF DISCOVERY:

The event was immediately apparent due to Control Board annunciator alarms and containment ventilation isolation valve position indication on the Control Board.

Also, Radiation Monitor R-11 digital readout indicated an invalid error code.

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F.

OPERATOR ACTION

Control Room. operators responded to the event by performing the applicable actions of alarm-response

- procedures E-16, A-25,

RMS, and E-20 and other actions as they deemed necessary.

This included the following:-

o Verifying that all containment ventilation isolation valves that were

open, closed as

designed, o

. Addressing the plant Technical Specifications to ens,ure. the plant was operating within these specifications.

o Declaring-R-11 inoperable per administrative procedure A-52.4 (Control of Limiting Conditions for Operating Equipment).

o Resetting-R-11, resetting the. containment ventilation isolation signal and restarting R-

10A, R-11, and. R-12. sample pump and verifying sample _f)ow-was re-established.

o Verifying that R-10A, R-11, R-12 RMS monitor readings returned to normal, o

Notifying the NRC and higher supervision of_the ESF actuation.

G.

SAFETY-SYSTEN RESPONSES:

The containment ventilation isolation valves that were open, closed automatically from the containment ventilation isolation signal.

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III.

CAUSE_OF. EVENT A.

IletEDIATE CAUSE:

i The containment ventilation-isolation was due - to an _

R-11 failure.

B.

ROOT CAUSE:

' Af ter -the -following' troubleshooting, the root cause still remains undetermined at this time:

o The. Instrument and control (I&C)

Department calibrated ' the - R-11 drawer with no adjustments required.

of Victoreen Inc., the manuf acturer of the instrument was called.

Victoreen Inc. concluded that', the probable cause was the micro-processor " locking-up" ' and it.was reset by the operators cycling

.its AC power supply off and on.

They suspect it may be'a'"one time" event.

IV.

ANALYSIS OF EVENT

This-- event nis reportable in accordance with 10CFR50.73,

' Licensee Event Report -system,

' item - (a) (2) (iv),

which requires reporting of, "any event-or condition that.

resulted in manual or automatic actuation of any Engineered Safety; Feature -(ESF) including the.. Reactor Protection System (RPS ) ".. -The containment ventilation isolation due to the R-11 failure,'was an automatic-actuation of an ESF

- subsystem.

An assessment was performed considering both the' safety consequences- 'and. implications ofl this event with the, following-results and conclusions:

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There were no operational or safety consequences or implications attributed to the containment ventilation isolation because:

o The containment ventilation isolation system operated as designed.

o The components affected were capabic of withstanding the isolation.

o The containment ventilation isolation was in the conservative direction.

Based on the above, it can be concluded that the public's health and safety was assured at all times.

V.

CORRECTIVE ACTION

A.

ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

o The Control Room operators, after determining that the containment ventilation isolation was due to the R-11 failure, reset R-11, reset the containment ventilation isolation signal and restored the system to pre-event status.

B.

ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

The following corrective action was taken:

o The R-11 drawer was replaced with a qualified spare and the removed R-11 drawer will be sent to Victorcen, Inc., so that they can attempt to duplicate the failure and determine the root

cause, o

Engineering has been involved in assessing the situation and will provide guidance for any desirable follow-up actions.

No other corrective action is planned until a root cause determination is accomplished.

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VI.

@DITIONAL INFORMATION A.

FAILED COMPONENTS:

The R-11 drawer was a model #942A, manuf actured by Victoreen, Inc.

B.

PREVIOUS LERs ON SIMIIAR EVENTS:

A similar LER event historical search was conducted with the following results:

LERs87-005, 88-007,89-011, 89-013, and 89-014 were similar events with known causes that appear much different than this event.

No other documentation of similar events could be identifibd.

C.

SPECIAL COMMENTS:

None.-

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