ML20168A704

Final ASP Analysis - Peach Bottom 3 (LER 278-79-031)

ML20168A704
Person / Time
Site:	Peach Bottom
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1979-031-00
Download: ML20168A704 (4)

Text

B-636 PRECURSOR DESCRIPTION AND DATA NSIC Accession Number: 150742 Date: June 22, 1979

Title:

Maifl Stock Sampling'System Lost at Peach Bottom 2 The failure sequence was:

1. During a severe electrical storm lightening struck at or near the Unit 2 main stack.

2. This resulted in initiation of HPCI and RCIC on Unit 3, tripped the unit 3 startup and emergency feed with emergency transfer to unit 2, and initiated a half scram in both units. The ability to autostart HPCI and ROIC was lost on unit 3 due to the inverter supplying power to the HPCI and RCIC.

3. A shutdown of unit 3 was commenced due to the inability of HPCI and RCIC to start automatically.

Corrective action:

1. The blown fuses in the inverter were replaced.

Design purpose of failed system or component:

1. RCIC provides a source of water during loss of feedwater event.

2. HPCI provides a source of high pressure water during a small LOCA.

Unavailability of system per WASH 1400: *HPCI: 8.8 x l0O2D RCIC: 8.0 xC lOUID 6

Unavailability of component per WASH! 1400: *FUSES, Premature open: 1.10 /Hr.

Unavailabiliti es are In units of per demand D-1. Failure rates are in units of per hour HR'1.

Lightning Struck The Main This Caused The Fuse In HPCI/RCIC Was Not Demanded Stack During An Potential The Inverter Feeding During The 45 Minutes Electrical Storm HPCI/RCIC To Blow Severe Requires To Replace The Core Fuses Damage A No No, ADS/LPCI/CS were operable ON No NSIC 150742 - Actual Occurrence of Main Stack Sampling System Lost at Peach Bottom 2

Potential Sequence Severe No.

Core Damage No 1 Yes No 3 Yes 0%

Yes 5 Yes 6 Yes 7 NSIC 150742 - Sequence of Interest of Main Stack Sampling System Lost at Peach Bottom 2

'RCIC and HPCI were probably operable through a manual bus transfer and manual initiation.

B-639 CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER: 150742 DATE OF LER: July 20, 1979 DATE OF EVENT: June 22, 1979 SYSTEM INVOLVED: HPCI/RCIC COMPONENT INVOLVED: Inverter fuse CAUSE: Lightning striking at or near the mainstack during dn electrical storm.

SEQUENCE OF INTEREST: Loss of Feedwater ACTUAL OCCURRENCE: Main Stack Sampling System Lost REACTOR NAME: Peach Bottom 3 DOCKET NUMBER: 278 REACTOR TYPE: BNR DESIGN ELECTRICAL RATING: 1065 Mwe REACTOR AGE: 5.9 yr VENDOR: General Electric ARCHITECT-ENGINEERS:

OPERATORS: Philadelphia Electric Company LOCATION: Nineteen miles S of Lancaster DURATION: 5.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> PLANT OPERAT ING CONDITION: 100% power SAFETY FEATURE TYPE OF FAILURE: Wa inadequate performance; (b) failed to start; Q)made inoperable; (d)____________

DISCOVERY METHOD: Operational Event COM4MENT: RCIC & HPCI are fed from the same inverter