ML20168A464
| ML20168A464 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1979-005-00 | |
| Download: ML20168A464 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
149230 Date:
March 21, 1979
Title:
Both Emergency Service Water Systems Inoperable at Arnold The failure sequence was:
- 1. The reactor was operating at 70% power and surveillance testing of the emergency service water system was underway.
- 2.
Strainer in both emergency service water systems were found to be plugged.
Corrective action:
- 1. The strainers were cleaned within 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
- 2. Self-cleaning strainers are to be installed during the 1980 refuel.
Design purpose of failed system or component:
The emergency service water System provides cooling water to the following systems given a loss of offsite power:
- 1. diesel generators
- 2. RHR pump seal coolers
- 3. RHR and core spray room cooling unit
- 4. HPCI room cooling unit
- 5.
RCIC room cooling unit
- 6. control building chiller
- 7. core spray pump motor bearing coolers Unavailability of system per WASH 1400:
- not given explicitly 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 operating Plugged strainers are Strainers cleaned at 76% power found in both emergency immediately water lines during-surveillance testing Potential Severe Core Damage No No -
Tech, specs. require a plant shutdown Perhaps -given LOOP several safety systems operation could be degraded or failed NSIC 149230 -
Actual Occurrence of Both Emergency Service Water Systems Inoperable at Arnold
Loss of Reactor Diesel Reactor Made Sub-RCIC/HPCI ADS/LPCI Long Offsite Scram Start and critical by the Initiates CS Tern Power Load SBLCS Or Rods Are Initiates Core Manually Driven In Cooling Potential Severe Core Damage Sequence No.
No Yes No Yes Yes No Yes Yes No Yes No Yes Yes Yes Yes 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 NSIC 149230 -
Sequence of Interest of Both Emergency Service Water Systems Inoperable at Arnold
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
149230 DATE OF LER:
April 4, 1979 DATE OF EVENT: March 21, 1979 SYSTEM INVOLVED: emergency service water system COMPONENT INVOLVED: strainers CAUSE:
the strainers were not cl.eaned often enough SEQUENCE OF INTEREST: loss of offsite power ACTUAL OCCURRENCE:both emergency service water systems inoperable at Arnold REACTOR NAME: Arnold DOCKET NUMBER:
50-331 REACTOR TYPE: BWR DESIGN ELECTRICAL RATING:
538 MWe REACTOR AGE:. 5.0 yr VENDOR:
GE ARCHITECT-ENGINEERS:
Bechtel OPERATORS:
Iowa Light and Power LOCATION:
8 miles NW of Cedar Rapids DURATION:
360(a) hours PLANT OPERATING CONDITION: 76%
SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start; QDmade inoperable; (d)____________
DISCOVERY METHOD: surveillance testing COMMENT:
-