ML19345D868
| ML19345D868 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/24/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Arnold D IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT |
| References | |
| NUDOCS 8012170634 | |
| Download: ML19345D868 (1) | |
Text
i
' '/
'o,,
UNITED STATES
[s%
g NUCLEAR REGULATORY COMMISSION s
REGION til 8
799 ROOSEVELT ROAD 0,
%.....o GLEN ELLYN. ILLINOIS 60137 OCT 24 m Docket No. 50-331 Iowa Electric Light and Power Company ATTN:
Mr. Duane Arnold President IE Towers P. O. Box 351 4
1 Cedar Rapids, IA 52406 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 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, L} James G. Kelppler.,a a E2 l 2 g Y s -
c, Director
Enclosure:
IE Information Notice No. 80-37 cc w/ encl:
D. Mineck, Chief Engineer Central Files Director, NRR/DPM Director, NRR/ DOR AEOD Resident Inspector, RIII PDR Local PDR NSIC TIC l
8 012170 Of
SSINS No.:
6835 Accession No.:
8008220249 UNITED STATES IN 80-37 NUCLEAR RECULAT0ftY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT
,[
D g
c, WASHINGTON, D.C.
20555
,, 3 a 1S 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 pcwer range nuclear detector, it was discovered that a significant amount of water was collected (approximately 100,000 gal) on the containment floor, in the containment sumps, &nd in the cavity under the reactor pressure vessel (RPV).
This collected water probably caused the detector malfunction, and the water in the cavity under the RPV is believed to have been deep enough to wet several 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 unknown 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 precent 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 coisture levels resulting from relatively small 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 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 i
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.
l There is no water level instrumentation in the cavity under the RPV, nor was j
there any indication outside the containment when these pumps are running.
The licensee has installed redundant sump level annunciated alarms in the control room and has installed an annunciated alarm in the control room to indicate if either submersible pump in the reactor cavity activates.
The l
licensee has also repaired the service water leaks, installed guide bushings i
on the sump pump control floats to prevent their binding, and has repaired the containment sump water level indicators.
l l
IN 80-37 October 24, 1980 Page 2 of 2 The licensee plans in the longer term to replace the containment fan unit cooling coils.
It is anticipatef. that results of a continuing NRC investigation i to this incident will result in issuance of an IE Bullutin and/or an NRR Generic Letter in the near future which will recommend or require specific licensees and applicant i.ctions.
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.
l l
l l
l i
i IN 80-37 October 24, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Date of Notice No.
Subject Issue Issued to' 80-36
{ailureofsteam 10/10/80 All nuclear power generator support bolting reactor facilities holding OLs or cps 80-35 Leaking and dislodged 1.0/10/80 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
~ ive-use shipments of s
radioactive materials 80-31 Maloperation of Gould-8/27/80 All light water reactor Brown Boveri Type 480 facilities holding Ols volt type K-6005 and or cps K-00N 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.
i function and non-essential control air at certain GE BWR facilities 80-29 Broken studs on Terry 8/7/80 All light water reactor turbine steam inlet facilities holding l
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 i
operating power reactor applicants j
'acilities l
80-28 Prompt reporting of 6/13/80 All applicants for and required information holders of nuclear power to NRC reactor cps l
l
- Operating Licenses or Construction Permits