ML20168A581

Final ASP Analysis - Oconee 2 (LER 270-79-007)

ML20168A581
Person / Time
Site:	Oconee
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1979-007-00
Download: ML20168A581 (4)

Text

PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:

153003 Date:

October 24, 1979

Title:

LPR Service Water Valves Left Closed Following Testing at Oconee 2 The failure sequence was:

1. Following a revision of the LPR system valve alignment procedure to provide a table of valve positions (to permit double verification of valve position),

a LPR system valve alignment was performed.

2. Two days later, with the reactor at 49% power, the LFR cooler service water valves were found to be improperly positioned, due to failure to include the LPR service water valves in the revised check list and failure of the per-sonnel performing the valve check to note that the service water valves were still included in the body of the procedure.

Corrective action:

1. The valves were returned to their correct positions.

2. The LPR procedure was rewritten to include the service water valves in the check list.

Design purpose of failed system or component:

The service water valves provide for the flow of cooling water to the LPR cooler following a loss of coolant accident.

Unavailability of system per WASH 1400:

• Low Pressure Recirculation:

1.3 X 10-2 /D Unavailability of component per WASH 1400:

• Valves, motor operated:

1 x 10-3 /1)

Unavailabilities are in units of per demand D-1.

Failure rates are in units of per hour HR-1

Reactor at Low Pressure Recirculation 99% Power System Cooler Service Water Outlet Valves Found Improperly Positioned As a Result of an Improperly Revised Procedure Potential Severe Core Damage No -

no LOCA NSIC 153003 -

Actual Occurrence for LPI Service Water Valves Left Closed Following a Test at Oconee 2

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

NSIC 153003 -

Sequence of Interest for LPR Service Water Valves Left Closed Following Testing at Oconee 2 Success requires operator detection and opening of closed valves prior to need for LPR.

CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:

153003 DATE OF LER: November 6, 1979 DATE OF EVENT:

October 24, 1979 SYSTEM INVOLVED:

Low Pressure Recirculation COMPONENT INVOLVED: LPR Cooler Service Water Valves CAUSE:

Valves improperly positioned, human error SEQUENCE OF INTEREST:

Small LOCA ACTUAL OCCURRENCE:

Failure to Properly Position Valves After Testing REACTOR NAME:

Oconee 2 DOCKET NUMBER:

50-270 REACTOR TYPE:

PWR DESIGN ELECTRICAL RATING:

887 MWe.

REACTOR AGE:

6.0 yr VENDOR:

B&W ARCHITECT-ENGINEERS:

DPC/Bechtel OPERATORS:

Duke Power Company LOCATION:

30 miles west of Greenville, SC DURATION:

48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> PLANT OPERATING CONDITION:

49% power SAFETY FEATURE TYPE OF FAILURE:

(a) inadequate'performance; (b) failed to start; (amade inoperable; (d) ___________

DISCOVERY METHOD:

Operator observation COMMENT:-