ML19326A050
| ML19326A050 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oyster Creek |
| Issue date: | 04/20/1972 |
| From: | Finfrock L JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19326A046 | List: |
| References | |
| NUDOCS 8001310626 | |
| Download: ML19326A050 (2) | |
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Jersey Central Powe'r & Light Company 8dAOISON Ay"ENUE AT PUNCH 80WL. RO A0 e MORRISTOWN, N.J. o796o e 339 4111
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April 20, 1972 Dr. Peter A. Morris, Director Division of Reactor Licensing United States A:c=ic Energy Co==ission Washington, 3. C. 20545 I
Dear Dr. Morris:
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gg Subject; Oyster Creek Station Docket No. 50-219 Loss of Secondary Containment In:cgrity The purpose of this letter is to report to you a violation of a L1=iting Condition for Opera: ion in that Secondary Contain=ent Integrity was not =aintained as required by Specification 3.5.3.1.
of our Technical Specificatient.
On April 11, 1972, during perfor=ance of a routine weekly surveillance test of isolation of the Reacter Building and ini:1ation of the Standby Gas Treatment Syste= due to si=ula:ed high radia:1on levels on the Reactor Building Operating Floor and in the Reac:or Building Ven*;11ation Exhaust due:s, the supply da=pers for the Reactor Building Ven:11acion Sys:e= failed to close es required.
As a result of this failure, Secondary Containment was not in effect.
Isolation of the Reac:or Building Ventilation Sys:ca supply da=per is initia:ed by "b" con: acts frc= the Reactor Building Ven:11ation Systc= supply fans, SF1-12, SF1-13, and SF1-14 vired in series.
- However, due to an electrical proble= with supply fan 1-13, which resultedJn the discovery that the =otor was shor:cd, i:s supply breaker was racked-out.
Thus, the logic ecatrol circuit for the da=pers was " opened", the nor=al situation with the fans in opera: ion. %#nen the re=sining fans were tripped during the surveillance tes: condue:ed at 2:00 a.=. on April 11, 1972, the logic control circuit was still open, the da=per control relays re=ained de-energized, and the ds=pers did not close.
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Dr. Peter A. Morris Page II April 20, 1972
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The logic circuit was restored by disconnecting the =otor leads from the breaker and racking-in the breaker. At 9:20 a.=.
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on April 11, 1972, an operabill:y check of Reactor 3uilding Isola:1on was conducted and proved to be satisfactory. A caution tag was placed at the fan con:rol switches in the Control Roc = to notify operators that if a supply fan breaker is racked-out,the Reactor Building supply damper isolation control logic is defeated unless a ju=per is installed in the breaker cabinet. A similar caution note is being stenciled locally on the supply fan breakers.
As noted in the FDSAR, the pri=ary objec:1ve of the Secondary Contain=ent Syste= is to =ini=12e ground level release of airborne radioactive =a:erials and to provide for con: rolled cieva:cd release of the building a:=osphere under acciden: condi: ions. The contain=ent syste=s, Pri=ary and Secondary, provide the principle =echanis= for mitilgation of accident consequences.
The off-si:e accident cor. sequences, however, are reis:1vely insensi:1ve to the Reactor 3uilding in-leakage rate as long as the Standby Cas Trea:=en: Sys:c can =aintain :he building at a vacuu=.
In this particular ins:ance, the supply and exhaust fans : ripped, the exhaus: da=pers closed, and the Standby Gas Treat =ent Syste= was initia:ed. 'Jith the above situation, the air supply to :he building was not only via the various in-leakage paths but also, and no doubt pri=arily, via the Reactor Building supply da=pers.
Any accident conditions postulated that require secondary contain=ent in de:er=ining environ = ental releases vould, under these conditions, have a second pa:h permitting release of :he Reactor Building air at approximately a 60-foot elevation.
,In order to prevent a reoccurrence of this incident, a circuit design change vill be i=ple=ented that will per:1: a Reactor Building supply fan breaker to be racked-ou: for =aintenance without defeating the Reactor Suilding supply da=per isola: ion logic.
Un:11 this design change can be,i=ple=en:cd, a s:anding order vill be issued instructing plant personnel in the appropriato practice to be followed to avoid defeating the Reactor Building supply da=per isolation lojic.
Very truly yours, f.
u.se'D Ivan R. Finfrockl Jr.
Manager, Nuclear Generating Stations IRF/pk ae o
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4 cc: Mr. J. P. O'Reilly, Director Division of Co pliance, Region I
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