ML20168A555
| ML20168A555 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1979-045-00 | |
| Download: ML20168A555 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
149961 Date:
June 3, 1979
Title:
HPCI Fails to Start When Turbine Stop Valve Fails to Open at Hatch 2 The failu~re sequence was:
- 1. During power ascension the reactor tripped due to a condensate system trip.
- 2. HPCI failed to initiate on low-low water level due to a failed turbine stop valve.
Water from HPCI mechanical seal cooling lines was leaking into the bracket drain cavity.
The bracket drain cavity line had a valve installed for unknown reasons.
This valve was closed which caused water to back up into the adjacent bearing housing and thus contaminate the pump oil.
- 3. The RCIC was out of service for unspecified reasons.
- 4. The reactor was placed in hot shutdown using the immediately repaired condensate system.
Corrective action:
- 1. The leaking seal line was replaced.
- 2. The oil system was drained, flushed and twice refilled.
- 3. The turbine bearing was inspected and found to be undamaged.
- 4. The valve in the bracket drain line was locked open and am investigation initiated to determine its significance.
Design purpose of failed system or component:
Unavailability of system per WASH 1400:
- HPCI:
8.8 x 10-2 /D RCIC:
8.0 x 10- 2/Dl Unavailability of component per WASH 1400:*
Unavailabilities are in units of per demand D-1. Failure rates are in units of per hour HR? 1.
Reactor trip HPCI failed to RCIC system Reactor water level during power initiate on was out controlled by con-accession due low-low reactor of service densate system which to condensate water inventory had been immediately system trip due to failed repaired turbine stop valve Potential Severe Core Damage ADS/LPCI & CS available NSIC 149961 -
Actual Occurrence for HFCI Fails to Start When Its Turbine Stop Valve Fails to Open at Hatch 2
Loss of Reactor RCIC/HPCId. Automatic LPCI or Long Feedwater Subcritical
Response
Depressurization CS Response Term Flow Adequate System Operates Adequate Core Cooling Potential Severe Core Damage Sequence No.
No Yes 2
No Yes Yes 3
4f 5
Yes 6
Yes 7
NSIC 149961 -
Sequence of Interest for HPCI Fails to Start When the Turbine Stop Valve Fails to Open at Hatch 2 1RCIC was out of service.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
149961 DATE OF LER: June 11, 1979 DATE OF EVENT:
June 3, 1979 SYSTEM INVOLVED:
HPCI COMPONENT INVOLVED:
water line, valves CAUSE: valve improperly closed, leaky water line, (human error)
SEQUENCE OF INTEREST: loss of feedwater flow ACTUAL OCCURRENCE:
HPCI fails to start when turbine stop valve fails to open at Hatch 2 REACTOR NAME: Hatch 2 DOCKET NUMBER:
50-366 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING: 784 MWe REACTOR AGE:.9 yr VENDOR: General Electric ARCHITECT-ENGINEERS:
Southern Services/Bechtel OPERATORS:
Georgia Power Company LOCATION:
11 miles N of Baxley, Ga.
DURATION:, N/A PLANT OPERATING CONDITION:
hot shutdown SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start;
_cnýade inoperable; (d)
DISCOVERY METHOD:
operational event COMMENT:
-