ML19345D558
| ML19345D558 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 10/27/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8012160062 | |
| Download: ML19345D558 (1) | |
Text
CENTRAL FILES
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UNITED STATES PDR:HQ f[,
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NUCLEAR REGULATORY COMMISSION LPOR
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ARUNGTON. TUAS 76011 STATE Oc ober 27, 1980 Docket No.
50-235 Cmahm Public ?cwer Distrie:
Al"IN :
'4. C. Jones, Divisien Y.anager -
Production Operaticus 1623 Harney Street Omaha, Nebraska 68102 Gentlenen:
This IE Information Notice is provided as an early notification of a possibly sign'#icant =at:er.
I: 3 expected that recipients will review the infor=ation for possible applicabili:7 :o their facility.
No specific actica or response is requested at :his eine.
If further NRC evaluations so indicate, an II Circular or Sulletin will be issued Oc racc= mend or request specific licensee ac icus.
If you have questicus regarding :his car:er, please centac: the Direc:or of the appropriate NRC Regional Office.
Sincerely,
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Karl V. Seyfrit Director F.nclosures:
1.
II Infor=aton Notice i
No. 30-37 i
7 'st of Recently Issued II Infor=ation Notices cc:
S. C. Stavens, F.anager For: Calhoun Station Post Offica 3cx 98 For: Calhoun, Nebraska 68102 i
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'lTED STATES
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8 611 RYAN PLAZA DRIVE. SUITE 1000 ARLINGTON, TEX AS 76011 1,,
October 24, 1980 l
Docket No. 50-285 Omaha Public Power District ATTN:
W. C. Jones, Division Manager -
Production Operations 1623 Harney Street Omaha, Nebraska 68102 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the infor-mation for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to reconrnend or request specific licensee actions.
If you have any questions regarding this matter, please contact this office.
Since rely, Y
W Karl V. Seyfrit Director
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Enclosures:
1.
IE Information Notice No. 80-37 2.
List of Recently Issued IE Information Notices cc:
S. C. Stevens, Manager Fort Calhoun Station Post Office Box 98 Fort Calhoun, Nebraska 68102 i
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8008220249 NUCLEAR REGULATORY C0" MISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Information Notice No. 80-37 Date:
October 24, 1980 Page 1 of 2 CONTAINMENT COOLER LEAKS AND REACTOR CAVITY FLOODING AT INDIAN POINT UNIT 2 Discription of Circumstances:
This Notice contains information regarding multiple service water leaks into containment with resulting damage to reactor instrumentation and potential damage to the reactor pressure vessel.
Upon containment entry on October 17, 1980 at Indian Point Unit 2, to repair a malfunctioning power range nuclear detector, it was discovered that a significant amount of water was collected (approximately 100,000 gal) on the con'.ainment floor, in the containment sumps, and in the cavity under the reacte pressure vessel (RPV). This collected water probably caused the ietector malfunction, and the water in the cavity under the RPV is believed tc have been deep enough to wet several feet of the pressure vessel lower head, c ausing an unanalyzed thermal stress condition of potential safety significan;e.
This condition resulted from the following combinati;n of conditions.
(1) Both containment sump pumps were inoperable, ore due to blown fuses from an unknown cause and the other due to binding of its controlling float; (2) The two containment sump level indicating lights wh!.ch would indicate increasing water level over the water level range present in the containment were stuck (on) and may have been for several days, leaving the operator with no operable instrumentation to measure water level in the containment; (3) The moisture level indicators in the containment did noc indicate high moisture levels, j
apparently because they are designed to detect pressurized hot water or steam i
leaks (i.e., a LOCA), and are nor.eusitive to the lower airborne moisture levels resulting from relatively sma'.i cold water leaks; (4) The hold-up tanks'which ultimately receive water pumped from the containment sump also receive Unit 1 process water, lab drain water, etc.
These ocher water sources masked the effect l
of cessation of water flows from the Unit 2 sump; (5) There were significant, multiple service water leaks from the containment fan cooling units directly onto the containment floor.
These coolers have a history of such leakage, which cannot be detected by supply inventory losses since the supply system (service water system) is not a closed system; (6) The two submersible pumps in the cavity under the Reactor Pressure Vessel were ineffective since they pump onto the con-tainment floor for ultimate removal by the (inoperable) containment sump pumps.
There is no water level instrumentation in the cavity under the RPV, nor was there any indication outside the containment when these pumps are running.
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IE Information Notice October 24, 1980 No. 80-37 Page 2 of 2 The licensee has installed redundant sump level annunciated alarms in fhe control room and has installed an annunciated alarm in the control room to indicate if either submersible pump in the reactor cavity activates.
The i
licensee has also repaired the service water leaks, installed guide bushings on the sump pump control floats to prevent their binding, and has repaired the containment sump water level indicators.
The licensee plans in the longer term to replace the containment fan unit cooling coils.
It is anticipated that results of a continuing NRC investigation into this incident will result in issuance of an IE Bulletin and/or an NRR Generic Letter in the near future which will recommend or require specific licensees and applicant actions.
In the interim, we recommend that all licensee ascertain that the potential does not exist for undetected water accumulation in the containment.
This Information Notice is provided to inform licensees of a possibly significant matter.
No written response to this Information Notice is required.
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IE Information No. 80-37 October 24, 1980 LISTING OF RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-30 Potential for Unaccept-8/19/80 All boiling water reactor able Interaction Between facilities holding power the Control Rod Drive Scram reactor Operating Licenses Function and Non-Essential (OLs) or Construction Control Air at Certain GE BWR Permits (cps)
Facilities 80-31 Maloperation of Gould-8/27/80 All light water reactor Brown Boveri Type 480 facilities holding volt type K-600S and Operating Licenses or and K-DON 600S circuit Construction Permits breakers (cps) 80-32 Clarification of certain 8/12/80 All NRC and agreement requirements for Exclu-state licensees sive-use shipments of radioactive materials 80-33 Determination of Tele-9/15/80 All teletherapy therapy Timer Accuracy (G3) licensees 80-34 Boron Dilution of Reactor 9/26/80 All Pressurized Coolant During Steam Water Reactor Generator Decontamination Facilities holding power reactor Operating Licenses (OLs) 80-35 Leaking and Dislodged 10/10/80 All categories G and Iodire-124 Implant Seeds G1 medical licensees 80-36 Failare of 'iceam 10/10/80 All nuclear power Generator Sopport Bolting reactor facilities holding Operating Licensees (OLs) or Construction Permits (cps)
Enclosure l
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