Information Notice 1980-37, Containment Cooler Leaks & Reactor Cavity Flooding at Indian Point Unit 2

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 IN 80-37 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.

a

Upon-containment entry on October 17, 1980 at Indian Point Unit 2, toa repair significant

malfunctioning power range nuclear detector, it was discovered that

amount of water was collected (approximately 100,000 gal) on the containment pressure

floor, in the containment sumps, and in the cavity under the reactor

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: from an

(1) Both containment sump pumps were inoperable, one due to blown fuses(2) The

unknown cause and the other due to binding of its controlling float;

two containment sump level indicating lights which would indicate increasing stuck

water level over the water level range present in the containment wereoperable

(on) and may have been for several days, leaving the operator with no

instrumentation to measure water level in the containment; (3) The moisture

level indicators in the containment did not indicate high moisture levels, or steam

apparently because they are designed to detect pressurized hot water moisture levels

leaks (i.e., a LOCA), and are not sensitive to the lower airborne

leaks; (4) The hold-up tanks which

resulting from relatively small cold water Unit 1 ultimately receive water pumped from the containment sump also receive the effect

process water, lab drain water, etc. These other water sources masked

of cessation of water flows from the Unit 2 sump; (5) There were significant, multiple service water leaks from the containment fan cooling units directlywhich

onto the containment floor. These coolers have a history of such leakage, cannot be detected by supply inventory losses since the supply systemin(service the cavity

water system) is not a closed system; (6) The two submersible pumps the con- under the Reactor Pressure Vessel were ineffective since they pump onto

containment sump pumps.

tainment floor for ultimate removal by the (inoperable) nor was

There is no water level instrumentation in the cavity under the RPV,

there any indication outside the containment when these pumps are running.

The licensee has installed redundant sump level annunciated alarms in theto

control room and has installed an annunciated alarm in the control roomThe

indicate if either submersible pump in the reactor cavity activates. bushings

licensee has also repaired the service water leaks, installed guide

on the sump pump control floats to prevent their binding, and has repaired

the containment sump water level indicators.

j ^ - f - W

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.

4' - v I

IN 80-37 October 24, 1980

RECENTLY ISSUED

TE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

80-36 Failure 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 480 facilities holding OLs

volt type K-600S and or CPs

K-DON 600S 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 Terry 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

80-23 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