ML20168A735

Final ASP Analysis - Three Mile Island 1 (LER 289-78-010)

ML20168A735
Person / Time
Site:	Crane
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1978-010-00
Download: ML20168A735 (4)

Text

B-47 4 PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:

137384 Date:

March 18, 1978

Title:

Two Makeup Pumps Trip During Testing at Three Mile Island 1 The failure sequence was:

1. During performance of the Emergency Sequence and Power Transfer Test, both makeup pumps failed to start after power was restored to their respective buses.

In one case, a lube oil pressure timer relay failed to close, and in the other case, a relay failed to disengage when the pumps initially tripped due to loss of power during the test.

Corrective action;

1. The timer relays were to be replaced during the refueling outage which was in existence during the test.

Design purpose of failed system or component:

1. The timer relay allows the pump to run for six seconds without normal lube oil pressure while the pump is initially coming up to speed.

2. The makeup pumps perform as emergency high pressure injection pumps for LOCA.

Unavailability of system per WASH 1400:*

8.6 x 10-3 Unavailability of component per WASH 1400:

• pump, failure to start:

1 x 10-3/D Unavailabilities are in units of per demand D-1.

Failure rates are in units of per hour HR-1.

Makeup pumps MU-PIA, MU-PIC Power restored MU-11IA start MU-PIC start MU-PIA, MU-PIC tripped to MU-PIA, nd run and run running and voltage MU-PIC buses on buses for MU-PIA, MU-PIC interrupted for testing during refueling Potential Severe Core Damage No No Yes to I1 No I

No No -

N~o LOCA & unit in shutdown NSIC 137384 -

Actual occurrence for Failure of Two Makeup Pumps During Testing at Three Mile Island 1

Small Reactor Auxiliary High Low Pressure LOCA*

Trip Feedwater and Pressure Recirculation Secondary Injection and LPR/HPI Heat Removal.

Cross-Connect Potential Severe Core Damage No Sequence No.

2 3

4 5

6 7

-I C7%

NSIC 137384 -

Sequence of Interest for Failure of Two Makeup Pumps During Testing at Three Mile Island 1

• With loss of offsite power.

B-47 7 CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:

137384 DATE CF LER:

April 5, 1978 DATE OF EVENT:

March 18, 1978 SYSTEM INVOLVED:

Makeup and High Pressure Injection COMPONENT INVOLVED:

Pumps CAUSE:

Malfunction of time delay relay.

,SrQUENCE OF INTEREST:

Small LOGA ACTUAL OCCURRENCE:

Relay failure.

REACTOR NAME:

Three Mile Island 1 DOCKET NUMBER:

50-289 REACTOR TYPE:

PWR DESIGN ELECTRICAL RATING:

819 MWe REACTOR AGE:

3.8 yr VENDOR:

B&W ARCHITECT-ENGINEERS:

Gilbert Associates, Inc.

OPERATORS:

Metropolitan Edison LOCATION:

10 milea BE of Harrisburg, PA DURATION:

360(a) hours PLANT OPERATING CONDITION:

0% power SAFETY FEATURE TYPE OF FAILURE:

(a) inadequate performance; (b) failed to start; (9made inoperable; (d)________

DISCOVERY METHOD:

During test.

COMME~NT:

Lost 2 of 3 makeup/high pressure injection pumps because of faulty timers.

These two pumps are normally those started by an SFAS signal.