ML19350D480
| ML19350D480 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde, Columbia, Diablo Canyon, San Onofre, Humboldt Bay, Rancho Seco, Washington Public Power Supply System, Satsop, Trojan |
| Issue date: | 03/26/1981 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| IEIN-81-09, NUDOCS 8104150629 | |
| Download: ML19350D480 (1) | |
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NUCLEAR REGULATORY COMMISSION
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SulTE 202, WALNUT CREEK PLAZA WAL*.UT CREEK CALIFORNIA 94596 March 26, 1981 MEMORANDUM T0: ALL THOSE ON IE INFORMATION NOTICE DISTRIBUTION LIST FR0ft:
IE, REGION V
SUBJECT:
IE INFORMATION NOTICE N0. 81-09:
DEGRADATION OF RESIDUAL HEAT REMOVAL (RHR) SYSTEft The attached IE Information Notice No. 81-09 was issued this date to the following licensees:
1.
Arizona Public Service Company (Palo Verde 1, 2 & 3, Docket Nos. 50-528, 50-529,50-530).
2.
Pacific Gas and Electric Company (Humboldt Bay Unit 3, Diablo Canyon Units 1 & 2, Docket Nos. 50-133,50-275,50-323).
3.
Portland General Electric Company (Trojan, Docket No. 50-344).
4.
Sacramento Municipal Utility District (Rancho Seco, Docket No. 50-312).
5.
Southern California Edison Company (San Onofre Units 1, 2 & 3, Docket Nos. 50-206, 50-361 & 50-362).
6.
Washington Public Power Supply System (WNP-1, WNP-2, WNP-3, WNP-4 &
UNP-5, Docket Nos. 50-397, 50-460, 50-508, 50-509 & 50-513).
Region V has made distribution to the Accessions Unit for the PDR, LPDR, NSIC, TIC and Central Files.
Enclosure:
IE Information Notice No. 81-09 j
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6835 Accession No.:
8011040280 IN 81-09 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 26, 1981 IE Information Notice No. 81-09:
DEGRADATION OF RESIDUAL HEAT REMOVAL (RHR)
SYSTEM Description of Circumstances:
Recent, repeated expressions of serious concern have been made regarding loss of shutdown cooling capability (IEB 80-12 and IN 80-20).
Nevertheless, an additional instance has occurred in which proper attention was not given to assure reliability of the shutdown cooling function.
On March 5,1981 during a shutdown at Beaver Valley, residual heat removal (RHR) flow was severely degraded while the water level was near the hot leg midpoint.
During the 54 minutes needed to sent both RHR pumps and add approxi-mately 600 gallons of water to the primary system, primary coolant temperature g
g increased from 102 F to 168 F.
The event occurred when water was slowly lost from the reference leg of a temporary (tygon tubing) differential pressure system installed to measure water level in the primary system.
There were no required surveillance procedures to check proper operation of the water level instrument.
Consequently, the reference leg water loss was not detected until the actual primary system water level decreased to about 6" below the indicated level, sufficiently low to allow air entrainment in the RHR suction line, which air-bound both RHR pumps.
Loss of shutdown cooling capability is a potentially significant contributor to the total risk associated with nuclear power (Reactor Safety Study, WASH - 1400, pg. 135.)
It is expected that licensees will review the circumstances of this event and take appropriate actions to assure shutdown cooling system operability. This notification, in conjunction with IEB 80-12 and IN 80-20, is intended to convey the seriousness of NRC concern with failures to maintain adequate decay heat removal provisions.
No written response to this information notice is required.
If you require additional information with regard to this subject, please contact the appropriate NRC Regional Office.
Attachment:
Recently issued IE Information Notices
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Attachment Ill 81-09 March 26, 1981 RECEtiTLY ISSUED IE IrlFORMATI0il fl0TICES Inf orma tion Date of flotice No.
Subject Issue Issued to 81-08 Repetitive Failures of 3/20/81 All power reactor Limitorque Operator SflB-4 facilities with an Motor-to-Shaf t Key 0L or CP 81-07 Potential Problem with 3/16/81 All power reactor Water-Soluble Purge Dam facilities with an Materials Used During OL or CP Inert Gas Welding 81-06 Failure of ITE Model 3/11/81 All power reactor K-600 Circuit Breaker facilities with an OL or CP 81-05 Degraded DC System at 3/13/81 All power reactor Palisades facilities with an OL or CP 81-04 Cracking in Main Steam 2/27/81 All power reactor Lines facilities with an OL 81-03 Checklist for Licensees 2/12/81 All power reactor Making flotifications of facilities with an Significant Events in OL Accordance with 10 CFR 50.72 l
81-02 Transportation of 1/23/81 All Radiography Radiography Devices licensees 81-01 Possible Failures of 1/16/81 All power reactor l
General Electric Type facilities with an i
i 80-45 Potential Failure of 12/17/80 All PWR facilities BWR Backup Manual Scram with an OL or CP Capability 80-44 Actuation of ECCS in the 12/16/80 All PWR facilities Recirculation Mode While with an OL or CP in Hot' Shutdown OL = Operating Licenses CP = Construction Permits