ML19290A431
| ML19290A431 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek, Crane |
| Issue date: | 04/20/1972 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19290A429 | List: |
| References | |
| NUDOCS 7911070610 | |
| Download: ML19290A431 (2) | |
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Jersey Central Powe'r & Light Company 6/.
NADI 5oM AV"ENU E AT PUNCH BOWL Ro AD e MORRISTOWN. N.J. 0796o e 539 6811
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Dr. Peter A. Morris, Director Division of Reactor Licensi:.g
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Dear Dr. Morris:
b Subj ect: Oyster Creek Station Docket 2io. 50-219 Loss of Secoadary Coatain=ent Integrity The purpose of this letter is to report to you a violation of a Limiting Condition for Operation in that Secondary Contain=ent Integrity was not maintained as required by Specification 3.5.3.1.
of our Technical Specifications.
s On April 11, 1972, during perfor= nce of a routine weekly surveillance test of isola: ion of the Reactor Building and initiation of the Standby Gas Treatment System due to simulated high radia: ion levels on the Reactor Building operating Floor and in the Reactor Building Ventilation Exhaust ducts, the supply dampers for the Reactor Building Ventilation Systes failed to close as required.
As a result of this failure, Secondary Contain=ent was not in effect.
Isolation of the Reactor Building Ventilation Syste= supply damper is initiated by "b" con: acts fro = the Reactor Zuilding Ventilatica System supply fans, SF1-12, SF1-13, and SF1-14 wired in series.
- However, due to an electrical probic= with supply fan 1-13, which resulted in the discovery that the =otor was shorted, its supply breaker was racked-out.
Thus, the logic control circuit for the da=pers was " opened", the nor:21 situation with the fans in operation.
b' hen the rc:aining fans were tripped during the surveillance tes: condue:cd at 2:00 a.m. on April 11, 1972, :he logic control circuit was still open, the da=per
. g ontrol relays re=ained de-energi:cd, and the da pers did not close.
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, o J\\ j; eo The logic circuit was restored by disconnecting the cotor leads from the breaker and racking-in the breaker.
A: 9:20 a.=.
' on April 11, 1972, an operabill:y check of Reactor Building Isola: ion was condue:cd and proved to be satisfactory.
A caution tag was placed at the fan con:rol switches in the Control Roo: to notify opera: ors that if a supply fan breaker is racked-ou:,the Reactor Building supply damper isolation control logic is defeated unless a ju per is installed in the breaker cabinet.
A si=ilar caution note is being stenciled locally on the supply fan breakers.
As noted in the FDSAR, the pri ary objective of the S condary Containment Sys:e= is to mini =ize ground level release of airborne radioactive sa:erials and :o provide for con: rolled eleva:ed release of the building a:=ospnere under acciden: conditions. The containten:
syste=s, Pri.ary and Secondary, provide the principle sechanis: for mitigation of acciden: consequences.
The off-site acciden: consecuences, however, are rela:ively insensi:ive to :he Reactor Building in-leakage rate as long as the Standby Gas Treat:en: Sys:c= can =aintain the building at a vacuu=.
In this particular instance, the supply and exhaust fans tripped, the exhaust da:pers closed, and the Standby Gas Treat ent Syste: was initiated.
With the above situation, the air supply to the building was not only via the various in-leakage paths but also, and no doubt primarily, via the Reactor Building supply dampers.
Any accident conditions postulated that require secondary contain=ent in de:cr=ining environmental releases would, under :hese conditions, have a second path permitting release of the Reactor Building air at approximately a 60-foot elevation.
In order to prevent a reoccurrence of this incident, a
circuit design change will be i=plemented that will per=it a Reactor Building supply fan breaker to be racked-out for maintenance wi:hout defeating the Reactor Sullding supply da:per isolation logic.
Until this design change can be. L:ple:ented, a s:anding order will be issued instructing plant personnel in the appropriate practice to be followed to avoid defeating the Reactor Building supply da:per isolation logic.
Very truly yours, j
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IvanR.FinfrocklJr.
Manager, Nuclear Genera:ing Stations IRF/pk Enclosures 1557 285 cc: Mr. J. P. O'Reilly, Director Division of Cc=pliance, Region I