05000339/LER-1981-025-03, /03L-0:on 810329,bottled Air Pressurization Sys Pressure Fell Below Required Min of 2,300 Psig.Caused by Inadvertent Safety Injection,Causing One Bank of Unit 2 Bottles to Depressurize

/03L-0:on 810329,bottled Air Pressurization Sys Pressure Fell Below Required Min of 2,300 Psig.Caused by Inadvertent Safety Injection,Causing One Bank of Unit 2 Bottles to Depressurize

ML20003E949
Person / Time
Site:	North Anna
Issue date:	04/13/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20003E942	List: 05000339/LER-1981-025, Forwards LER 81-025/03L-0 05000339/LER-1981-025-03, /03L-0:on 810329,bottled Air Pressurization Sys Pressure Fell Below Required Min of 2,300 Psig.Caused by Inadvertent Safety Injection,Causing One Bank of Unit 2 Bottles to Depressurize
References
LER-81-025-03L-02, LER-81-25-3L-2, NUDOCS 8104170548
Download: ML20003E949 (2)

LER-1981-025, /03L-0:on 810329,bottled Air Pressurization Sys Pressure Fell Below Required Min of 2,300 Psig.Caused by Inadvertent Safety Injection,Causing One Bank of Unit 2 Bottles to Depressurize

Event date:
Report date:
3391981025R03 - NRC Website

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O u.S. NuctEAR RtcUtATORY COMM1SS10N LICENSEE EVENT REPORT CONTROL BLOCK / / / / / / / (1)

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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DOCKET NUMBER EVENT DATE REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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/ On March 29, 1981, with Unit II in Mode 1, the bottled air pressurization system /

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/ pressure fell below the required minimum of 2300 PSIG. Since a redundant set of /

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/ bottles with 100% capacity was available if needed, the health and safety of the /

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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/S/G/ (11) /X/ (12) /Z/ (13) /X/X/X/X/X/X/ (14) /Z/ (15)

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ACTION FUTURE EFFECT 7 HUTDOWN ATTACHMENT NPRD7 PRT8E COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER f l/ (18) /Z/ (19) /Z/ (20) /Z/ (21) /0/0/0/0/ (22) DY/ (23) /N/ (24) /A/ (25) /X/9/9/9/ (26) v CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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/ The inadvertent safety injection on Unit I (in mode 5 at the time) caused one

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/ bank of the Unit II bottles to depressurize to 2150 PSIG. Safety injection was /

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/ reset, the bottled air was isolated, and recharging of the system commenced.

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FACILITY METHOD OF STATUS

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/ (30) /B/ (31) / Operator Observation

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ACTIVITY CONTEhT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION (39)

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LOSS OF OR DAMAGE TO FACILITY (43)

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PUBLICITY ISSUED DESCRIPTION (45)

NRC USE ONLY

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NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 t

8104170548

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Virginia Electric and Power Company i

North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docket No. 50-339 Report No. LER 81-025/03L-0

Description of Event

On March 29, 1981, with Unit II in mode I, the bottled air pressuri-zation system pressure fell below the required minimum of 2300 PSIG.

This event is contrary to T.S. 3.7.7.1 and reportable pursuant to T.S.

6.9.1.9.b.

Probable Consequences of Occurrence Since a redundant set of air bottles with 100% capacity remained available to pressurize the control room / emergency switchgear area if needed, the public health and safety were not affected.

Cause of Event

This event was caused by an inadvertant safety injection on Unit I (in mode 5 at the time).

A safety injection signal on either unit discharges one bank of air bottles on each unit. Further depressurization of the Unit II air bottles was prevented by resetting the bottled air system discharge signal in the control room.

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Immediate Corrective Action

The redundant set of bottles was manually valved in. The partially discharged set of bottles was valved out and recharged.

Scheduled Corrective Action No scheduled corrective action required.

t Actions Taken to Prevent Recurrence I

No further action required.

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Generic Implications i

l There are no generic implications to this event.

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