ML16340A599
| ML16340A599 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 09/27/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7910180060 | |
| Download: ML16340A599 (16) | |
Text
9 UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLAZA WALNUTCREEK, CALIFORNIA94596 September 27.
1979 Docket icos.
50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:
Nr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
The enclosed Bulletin 79-24 is forwarded to you for action.
Written responses are required.
If you desire additional information regarding this-matter, please contact..this office.
Sincerely,
/C~k~~4~
R. H. Engelken Director
Enclosures:
l.
Designated Applicants for Operating Licenses cc w/enclosures:
J. Worthington, PGSE W. Raymond, PG&E R.
- Ramsay, PG8E, Diablo Canyon 7910180 0
C
~l
Accession No. 7908220114 SSINS No:
6820 UNITED STATES NUCLEAR REGULATORY COt~it1ISS ION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 September 27, 1979 FROZEN LINES Summary:
IE Bulletin No. 79-24 On January 3, 1979, an unusual, event occur red at, Davis-Besse, Unit 1.
The event involved the freezing of the water in a portion of the high pressure coolant injection (HPCI) system recirculation line that is common to both high pressure coolant injection pumps.
The l,ine was not thawed until January 5, 1979, and the event was not reported to NRC until'arch 12, 1979.
In addition, over the past five years, there have been several events involving frozen instrument and sampling lines.
Description of Circumstances:
The condition was discovered on January 3, 1979, while the reactor was operating at approximately 96 percent power.
Durinq a monthly surveillance test of the HPCI pumps, there was no flow through the recirculation line from the pump discharge=to the Borated Water Storage Tank (BWST).
Investigation revealed that water in a portion of the line exposed to the outside weather was frozen.
This portion of the line to the BWST is common to both HPCI pumps.
The line has redundant heat tracing (a heated wire to prevent freezing); it is insulated;
. hnd it has a low-temperature alarm system to warn of freezing conditions.
Water in the line froze apparently because of prolonged sub-freezing temperatures and a defect in the insulation.
There was no apparent malfunction of the heat tracing or temperature alarm circuits, although the temperature sensing
- elements,
=
are located in an area not exposed to the coldest temperature conditions.
This recirculation line serves two purposes:
One is to provide a flow path for surveillance testing, and the other is to provide a minimum flow path to prevent possible damage to the pump in the event it is operated against a
closed discharg valve or a reactor coo'1ant system pressure greater than the maximum discharge pressure of the pump (approximately 160Q psig).
In the initial review of the event on January 3, 1979, the licensee concluded that the pumps were still operable with the recirculation line frozen.
Therefore, no immediate action was taken to thaw the frozen section of the line.
On January 5,
1979, the line was thawed and the surveillance test of the pumps was successfully completed.
IE Bulletin No. 79-24 September 27, 1979 Paqe 2 of 2 Cause of Causes:
This event is attributed to an inadequate design.
The heat tracing provided on this recirculation line was unable to prevent freezing when the line was exposed to sub-freezinq temperatures for a prolonged period of time.
The temperature sensors which control the heat tracing and which triqaer the low-temperature alarm were located in an area not exposed to the coldest temperatures to which the piping is subjected.
Cornective Action:
To prevent recurrence, the licensee increased the temperature setting of the thermostat for the heat tracing on the recirculation line.
- Further, a temporary enclosure was built around the line and additional heat tracing was installed.
After the line was thawed and blown down, surveillance testing to verify pump operability was performed.
An engineering evaluation was initiated by the licensee to develop long-term corrective action.
Other Frozen Lines:
In addition to this event at Davis-Besse, there have been many events involving frozen instrument and sampling lines.
During the last five years, facilities experiencing events of this kind include:
Arkansas Nuclear One Davis-Besse Duane Arnold
.Hatch Fitzpatrick Haddam t<eck Indian Point Millstone Oconee Pil grim Point Beach Salem Surry Trojan Zion Action To Be Taken:
All licensees and construction permit holders receiving this Bulletin for action are -requested to review their plants to determine that adequate protective measures have been taken to assure that safety-related
- process, instrument, and sampling lines do not freeze during extremely cold weather.
The results of these reviews should be reported to the Regional Director by October 31, 1979.
Approved by GAO (R0072); clearance expires 7/31/80.
Approval was given under a blanket clearance specifically for generic problems.
Enclosure:
Listing of IE Bulletins Issued in Last Six Months
~p IE Bulletin No. 79-24 September 27, 1979 LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Enclosure Page 1 of 4 Bulletin No.
79-23 Subject Potential Failure of Emergency Diesel Generator Field Exciter Transformer Date Issued 9/12/79 Issued To All Power Reactor Facilities with an Operatinq License or a construction permit 79-14 Seismic Analyses For
. (Supplement
- 2) As-Built Safety-Related Piping Systems 9/7/79 All Power Reactor Facilities with an OL or a CP 79-22 Possible Leakage of Tubes 9/5/79 of Tritium Gas in Time-pieces for Luminosity To Each Licensee who Receives Tubes of Tritium Gas Used in Timepieces for Luminosity 79-13 (Rev.
1)
Cracking in Feedwater System Pipinq 79-02 Pipe Support Base Plate (Rev.
1)
Designs Using Concrete (Supplement
- 1) Expansion Anchor Bolts 8/30/79 8/20/79 All Designated Applicants for OLs All power Reactor Facilities with an OL or a CP 79-14 (Supplement) 79-21 79-20 79-19 79-18 Seismic Analyses For As-Built Safety-Related Piping Systems Temperature Effects
=on Level Measurements
, Packaging Low-Level Radioactive Haste for Transport and Burial Packaging Low-Level Radioactive Haste for Transport and Burial Audibility Problems Encountered on Evacuation 8/1.5/79 8/13/79 8/10/79 8/10/79 8/7/79 All Power Reactor Facilities with an OL or a CP All PHRs with an operating license All Materials Licensees who did not receive Bulletin No. 79-19 A1'I Power and, Research Reactors with OLs, fuel facilities except uranium mills, and certain materials licensees All Power Reactor Facilities with an Operating License
IE Bulletin No. 79-24 September 27, 1979 0
Enclosure Page 2 of 4 Bulletin No.
Subject LISTING OF IE BULLETINS ISSUED IN LAST SIX MONTHS Date Issued Issued To 79-OSC506C Nuclear Incident at Three 7/26/79 thile Island - Supplement To all PHR Power Reactor Facilities with an OL 79-17 Pipe Cracks in Stagnant Borated )later Systems at PHR Plants 7/26/79 All PMP.'s with operating license 79-16 Vital Area Access Controls 7/26/79 All Holders of and applicants for Power Reactor Operating Licenses who anticipate loading fuel prior to 1981 79-14 Seismic Analyses For (Revision 1)
As-Built Safety-Related Piping System 7/18/79 A'll Power Reactor Facilities with an OL or a CP 79-15 79-14 79-13 79-02 (Rev.
1)79-01A Deep Draft Pump Deficiencies Seismic Analyses for As-Built Safety-Related Piping System Cracking In Feedwater System Piping Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts Environmental equal ificat ion of Class lE Equipment (Deficiencies in the Envi-ronmental gualification of ASCO Solenoid Valves) 7/11/79 7/2/79 6/25/79 6/21/79 6/6/79 All Power Reactor Licensees with a CP and/'or OL All Power Reactor facilities with an OL or a CP All PHRs with an OL for action. All BMRs with a CP for information.
All Power Reactor Facilities with an OL or a CP All Power Reactor Facilities with an OL or CP
IE Bulletin No. 79-24 September 27, 1979 LISTING OF IE BDLLETINS ISSUED IN LAST SIX HONTHS Enclosure Page 3 of 4 Bulletin No.
79-12 79-11 79-10 79-09 79-08 Subject Short Period Scrams at BMR Facilities Faulty Overcurrent Trip Device in Circuit Breakers for Engineered Sa. ety Systems Requalification Training Program Statisti.cs Failures of GE Type AK-2 Circuit Breaker in Safety Related Systems Events Relevant to BWR Reactors Identified During Three Hile Island Incident Date Issued 5/31/79 5/22/79 5/11/79 4/17/79 4/14/79 Issued To All GE BMR Facilities with an OL All Power Reactor Facilities with an OL or a CP All Power Reactor Facilities with an OL All Power Reactor Facilities with an OL or CP All BMR Power Reactor Facilities with an OL 79-07 Seismic Stress Analysis 4/14/79 of Safety-Related Piping All Power Reactor Facilities with an OL or CP
~79-068 79-06A (Rev 1)79-06A 79-06 Review of Operational Errors and System His-alignments Identified During the Three Mile Island Incident Review of Operational
'rrors and System His-alignments Identified During the Three Nile Island Incident Review of Operational Err ors and System His-alignments Identified During the Three Mile Island Incident Review of Operational Errors and System His-alignments Identified During the Three Nile Island Incident 4/14/79 4/18/79 4/14/79 4/11/79 All Combustion Engineer-ing Designed Pressurized Mater Popover Reactor Facilities with an Operating License All Pressurized Water Power Reactor Facilities of Westinghouse Design with an OL All Pressurized Mater Power Reactor Facilities of Westinghouse
IE Bulletin No. 79-24 September 27, 1979 Enclosure
'age 4 of 4 LISTING OF IE BULLETINS ISSUED IN LAST SIX SIX tIONTHS Bulletin No.
Subject Date Issued Issued To 79-058 79-05A 79-05 Nuclear Incident at Three Nile Island Nuclear Incident at Three Nile Island Nuclear Incident at Three thile Island 4/21/79 4/5/79 4/2/79 All BQl Power Reactor Facilities with an OL All BNl Power Reactor Facilities with an OL All Power Reactor Facilities with an OL and CP
Salem 2
North Anna 2 Diablo Canyon 1
5 2
Sequoyah I
HcGuire 1
San Onofre 2
Summer Watts Bar 1 5 2
DESIGNATED APPLICANTS FOR OPERATING LICENSES