Information Notice 1980-37, Containment Cooler Leaks & Reactor Cavity Flooding at Indian Point Unit 2
| ML031180421 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, 05000000 |
| Issue date: | 10/24/1980 |
| From: | NRC/OI |
| To: | |
| References | |
| IN-80-037, NUDOCS 8008220249 | |
| Download: ML031180421 (3) | |
SSINS No.:
6835 Accession No.:
8008220249 UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND.ENFORCEMENT
'HASHINGTON, D.C.
20555
October 24, 1980
IE Information Notice Mo. 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 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) 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 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 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
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 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.
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IN 80-37 October 24, 1980 The licensee plans in the loncer 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 significat
matter.
No written resoonse to this Information Notice is required.
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October 24, 1980
RECENTLY ISSUED
TE INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issue
Issued to
80-36
80-35
80-34
80-33
80-32
80-31
80-30
80-29
Failure of steam
generator support bolting
Leaking and dislodged
Iodine-124 implant seeds
Boron dilution of reactor
coolant during steam
generator decontamination
Determination of teletherapy
timer accuracy
Clarification of certain
requirements for Exclu- sive-use shipments of
radioactive materials
Maloperation of Gould-
Brown Boveri Type 480
volt type K-600S and
K-DON 600S circuit
breakers
Potential for unaccept- able interaction between
the control rod drive scram
function and non-essential
facilities
Broken studs on Terry
turbine steam inlet
10/10/80
10/10/80
9/26/80
9/15/80
8/12/80
8/27/80
8/19/80
8/7/80
All nuclear power
reactor facilities
All categories G and
G1 medical licensees
All pressurized water
reactor facilities
holding power reactor OLs
All teletherapy
(G3) licensees
All NRC and agreement
state licensees
All light water reactor
facilities holding OLs
or CPs
All boiling water reactor
facilities holding power
All light water reactor
facilities holding
Supplement to
80-06
Notification of
significant events at
operating power reactor
facilities
7/29/80
All holders of reactor
and near-term OL
applicants
80-23
Prompt reporting of
required information
to NRC
6/13/80
All applicants for
holders of nuclear
reactor CPs
and
power
- Operating Licenses or Construction Permits