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 Unavailability of component per WASH! 1400: *FUSES, Premature open: 1.10 6 /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 The Inverter Feeding During The 45 Minutes Electrical Storm HPCI/RCIC To Blow Requires To Replace The Fuses Potential Severe Core Damage A

No No, ADS/LPCI/CS were operable No ON NSIC 150742 -

Actual Occurrence of Main Stack Sampling System Lost at Peach Bottom 2

Potential Severe Core Damage No Yes No Yes Yes Yes Yes Sequence No.

1 3

0%

5 6

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