ML17296B134
| ML17296B134 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/24/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 8012170725 | |
| Download: ML17296B134 (8) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLA2A WALNUTCREEK, CALIFORNIA94598 I
( '".
I uQ Docket Nos.
50-528, 50-529, 50-530 Arizona Public Service Company P. 0.
Box 21666 Phoenix, Arizona 85036 Attention:
Mr. E.
E.. Van Brunt, Jr.
Vice President, Nuclear Projects Gentlemen:
This Information Notice is being forwarded to you for information.
No written response to this Information Notice is required.
If you have any questions related to the subject, please contact this office.
Sincerely, Sr%
R.
H. Engelken Director
Enclosures:
1.
IE Information Notice No. 80-37 2.
List of Recently Issued Information Notices.
cc w/enclosures:
F.
M. Hartley, APS
UNITED STATES NUCLEAR REGULATORY COMMISS ION OFFICE OF INSPECTION AND-ENFORCEMENT
'JASHINGTON, D.C.
20555 SSINS No.:
6835 Accession Ho.:
8008220249 IH 80-37 October 24, 1980 IE Information Notice Ho. 80-37:
COHTAIHMEHT COOLER LEAKS AND REACTOR CAVITY FLOODING AT IHDIAN POINT UNIT 2 Discri tion 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..
Uponmontainment 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 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 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) Hoth 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 present in the containment were stuck (on) and may have been for several
- days, leav'ing 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 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 fl'oor.
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'ubmersible 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 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 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.
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 anticioated 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 significat matter.
Ho written response to this Information Notice"is required.
IN 80-37 October 24, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Notice No. 80-36 80-35 80-34 Sub.j ect Failure of steam aenerator support bolting Leaking 'and dislodged Iodine-124 implant seeds I
Boron dilution of reactor coolant during steam aenerator decontamination Date of Issue 10/10/80 10/10/80 9/26/80 Issued to
,All nuclear power reactor facilities holding OLs or CPs All categories G and G1 medical licensees All pressurized water reactor facilities holding power reactor OLs 80-33 80-32 Clarification of certain requirements for Exclu-sive-use shipments of radioactive materials 8/12/80 Determination of tel etherapy 9/15/80 timer accuracy All teletherapy (G3) licensees All NRC and agreement state licensees 80-31 80-30 80-29 Supplement to 80-06 80-28 t~aloperation of Gould-Brown Boveri Type 480 volt type K-600S and K-DON 600S circuit breakers Potential for unaccept-abl'e interaction between the control rod drive scram function and non-essential control air at certain GE HHR facilities Broken studs on Terry turbine steam inlet flange Notification of significant events at operating power reactor facilities Prompt reporting of required information to NRC 8/27/80 8/19/80 8/7/80 7/29/80 6/13/80 All light water reactor facilities holding OLs or CPs All boiling water reactor facilities holding power reactor OLs or CPs.
All light water reactor facilities holding power reactor OLs or CPs*
All holders of reactor and near-tenn OL applicants All applicants for and holders of nuclear power reactor CPs
- Operating Licenses or Construction Permits