ML20156A146
| ML20156A146 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/04/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1980-077-00 | |
| Download: ML20156A146 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
161906 Date:
November 24, 1980
Title:
RCIC and HPCI Inoperable at Quad-Cities 2 The failure sequence was:
- 1. During performance test of the monthly operability at 99% power, the RCIC discharge isolation valve would not open from the control room.
This caused RCIC to be inoperable.
A torque switch on the valve was faulty.
- 2.
HPCI was subsequently declared inoperable due to an oil leak in the HPCI turbine stop valve actuator cover.
- 3.
An orderly shut down was commenced.
Corrective action:
- 1.
The RCIC torque switch was replaced before shutdown was reached and the shutdown was terminated.
- 2.
The HPCI valve actuator cover was replaced with a cover from Unit I.
- 3.
About 10 h was required to correct the simultaneous loss of RCIC and HPCI.
Design purpose of failed system or component:
- 1.
RCIC provides for reactor water level control given a loss of feed-water.
- 2.
HPCI provides for water level control given a small break LOCA.
RCIC performance tests were under wey while at full reactor power The RCIC discharge isolation valve fails to open, leaving RCIC inoperable Potential Severe Core Damage No No - but violates Tech. Specs.
No -
- ADS, LPCI/CS available No NSIC 161906 - Actual Occurrence of RCIC and HPCI Inoperable at Quad Cities 2
Loss of Reactor Standby RCIC/HPCI Automatic LPCI or Long Feedwater Scram Liquid
Response
Depressurization CS Response Term Flow Control Adequate System Operates Adequate Core Initiated Cooling Potential Sequence Severe No.
Core Damage No Yes 1
2 3
No Yes Yes Yes 4
5 6
7 8
No Yes Yes Yes 9
10 NSIC 161906 - Sequence of Interest for RCIC and HPCI Inoperable at Quad Cities 2
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
161906 LER NO.:
80-077 DATE OF LER:
November 24, 1980 DATE OF EVENT:
November 16, 1980 SYSTEM INVOLVED:
RCIC and HPCI systems COMPONENT INVOLVED:
Torque switch; turbine stop valve CAUSE:
Failure of the torque switch; oil leak SEQUENCE OF INTEREST:
Loss of feedwater ACTUAL OCCURRENCE:
RCIC and HPCI inoperable at Quad-Cities 2 REACTOR NAME:
Quad-Cities 2
DOCKET NUMBER:
265 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
789 MWe REACTOR AGE:
8.6 years VENDOR:
General Electric ARCHITECT-ENGINEERS:
Sargent & Lundy OPERATORS:
Commonwealth Edison Co.
LOCATION:
20 miles NE of Moline, Illinois DURATION:
360 h (estimated)
PLANT OPERATING CONDITION:
99% power TYPE OF FAILURE:
Failed to start; made inoperable DISCOVERY METHOD:
Testing COMMENT:
- ADS, LPCI, and core spray were available as backup systems.