ML20168A732

Final ASP Analysis - St. Lucie 1 (LER 335-78-017)

ML20168A732
Person / Time
Site:	Saint Lucie
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1978-017-00
Download: ML20168A732 (4)

Text

May 14, 1978 Off-site Power Lost at St. Lucie 1 lure sequence was:

h the reactor shut down for refueling, improper switching at one substation improper connection of both 240 KV/138 KV autotransformer polarizing rent transformer circuits at another substation resulted in a total loss off-site power.

diesel-generator was inoperative because of maintenance.

second diesel-generator started and assumed safety-related loads until

-site power was restored.

ive action; improper polarization of circuits at the one substation was corrected.

purpose of failed system or component:

-site power provides the preferred source of electric power to safety-ated equipment when the unit generator is not in operation.

lability of system per WASH 1400:

• loss of off-site power: 2 x 10-5 /hr lability of component per WASH 1400:* diesel generator: 3 x 10-2 /D 1

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

hut down Switching errors at one Operable diesel- Potential ling and substation and improper generator starts Severe l-generator connection of both and safety-related Core maintenance 240 KV1138 KV autotrans- loads Damage former polarizing current transformer circuits at another substation result in a total loss of of fsite power No No - reactor in refueling and off-site power lost for only 8 minutes No 139565 - Actual Occurrence for Offsite Power Lost at St. Lucie 1

2 3

4 5

6 7

8 9

10 11 12 13 65 - Sequence of Interest for Offsite Power Lost at St. Lucie 1 luded in mitigation procedures.

N NUI'ER: 139565 June 13, 1978 May 14, 1978 D: off-site power LVED: switchyard switches and polarizing current transformer circuits hing error and installation error , human error NTEREST: loss of offsite power with reactor trip NCE: loss of offsite power during refueling St. Lucie 1

50-335 PWR ICAL RATING: 802 MWe 2.1 yr ustion Engineering INEERS: Ebasco Florida Power & Light Co.

2 m=j~es.SE~of,.Fort.?ierce, Fla.

A NG CONDITION: refueling E TYPE OF FAILURE: (a) inadequate performance; (b) failed to start;

. (C)made inoperable; (d) _________

HOD: during operational event