ML19340C836
| ML19340C836 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 10/24/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8012170661 | |
| Download: ML19340C836 (1) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION 3
r REGION lli 8
799 ROOSEVELT ROAD o
GLEN ELLYN. ILLINOIS 60137 o
OCT 2 4 M Docket No. 50-358 Cincinnati Gas and Electric Company ATTN:
Mr. Earl A. Borgmann Senior Vice President Engineering Services and Electric Production 139 East 4th Street Cincinnati, OH 45201 Gentlemen:
This IE Information Notice No. 80-37 is provided as an early notification of a possibly significant matter.
It is expected that recipients will review i
the information 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 recommend or request specific licensee actions.
If you have questions regarding this matter, please contact this office.
Sincerely, N/
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,y mes G. Keppler Director
Enclosure:
IE Information Notice No. 80-37 cc w/ enc 1:
Mr. J. R. Schott, Plant Local PDR t
Superintendent NSIC j.
Central Files TIC Director, NRR/DPM Harold W. Kohn, Power Director, NRR/ DOR Siting Commission AEOD Citizens Against a Radioactive Resident Inspector, RIII Environment PDR Helen W. Evans, State of Ohio 4
s SSINS No.:
6835 Accession No.:
8008220249 g
UNITED STATES IN 80-37 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT r
WASHINGTON, D.C.
20555 p
October 24, 1980 IE Information. Notice No. 80-37:
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 dat a significant amount of water was collected (approximately 100,000 gal) on the containment floor, in the containment sumps, and in the cavity under the reactor pressure vessel (RPV).
This collected water probably caused the detector malfunction, and the wate.- in the cavity under the RPV is believed to have been deep enough to wet severai feet of the pressure vessel lower head, causing an unanalyzed thermal stress condition of potential safety significance.
This condition resulted from the following combination of conditions:
(1) Both containment sump pumps were inoperable, one due to blown fuses from an unknov cause and the other due to binding of its controlling float; (2) The two containment sump level indicating lights which 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 not indicate high moisture levels, apparently because they are designed to detect pressurized hot water or steam leaks (i.e., a LOCA), and are not sensitive to the lower airborne moisture levels resulting from relatively small cold water leaks; (4) The hold up tanks nich ultimately receive water pumped from the containment sump also receive Unit 1 process water, lab drain water, etc.
These other water sources masked the effect 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.
The licensee has installed redundant sump level anr.unciated alarms in the t
control room and has installed an annunciated alarm in the control room to indicate if either submersible pump in the rractor cavity activates.
The 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.
.s IN 80-37 i
j October 24, 1980 t
Page 2 of 2
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The licensee plans in the longer term to replace the containment fan unit 1
cooling coils.
i It.is anticipated tk results of a continuing NRC investigation into this incident will resu' n issuance of' an IE Bulletin and/or an NRR Generic Letter in the ner ature which will recommend or require specific licensees and applicant a sns.
In the interim, we recommend that all licensee ascertain that tue potential does not exist for undetected water accumulation I
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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IN 80-37 October 24, 1980 I
RECENTLY ISSUED IE INFORMATION NOTICES Information Date of Notice No.
Subject Issue Issued to 80-36 Tailure of steam 10/10/80 All nuclear power generator support bolting reactor facilities holding OLs or cps 80-35 Leaking and dislodged 10/10/80 All categories G and Iodine-124 implant seeds G1 medical licensees 80-34 Boron dilution of reactor 9/26/80 All pressurized water coolant during steam reactor facilities generator decontamination holding power reactor OLs 80-33 Determination of teletherapy 9/15/80 All teletherapy timer accuracy (G3) licensees 80-32 Clarification of certain 8/12/80 All NRC and agreement requirements for Exclu-state licensees sive-use shipments of radioactive materials 80-31 Maloperation of Gould-8/27/80 All light water reactor Brown Boveri Type 420 facilities holding OLs volt type K-6005 and or cps K-D0N 6005 circuit breakers 80-30 Potential for unaccept-8/19/80 All boiling water reactor able interaction between facilities holding power the control rod drive scram reactor OLs or cps.
function and non-essential control, air at certain GE BWR facilities 80-29 Broken studs on T9rry 8/7/80 All light water reactor turbine steam inlet facilities holding flange power reactor OLs or cps
- Supplement to Notification of 7/29/80 All holders of reactor 80-06 significant events at and near-term OL operating power reactor applicants facilities 80-28 Prompt reporting of 6/13/80 All applicants for and required information holders of nuclear power to NRC reactor cps
- Operating Licenses or Construction Permits