Information Notice 1986-37, Degradation of Station Batteries

Degradation of Station Batteries

ML031250024
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	05/16/1986
From:	Jordan E NRC/IE
To:
References
IN-86-037, NUDOCS 8605130028
Download: ML031250024 (3)

SSINS No.: 6835 IN 86-37

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

May 16, 1986

IE INFORMATION NOTICE NO. 86-37:

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This notice is provided to alert recipients to a significant problem occurring

in station batteries.

It is expected that recipients will review this information

for applicability to their facilities and consider action, if appropriate, to

preclude a similar problem occurring at their facilities.

However, suggestions

contained in this notice do not constitute NRC requirements; therefore, no

specific action or written response is required.

Description of Circumstances

While shut down, recent inspections at the Rancho Seco Nuclear Power Plant

revealed substantial degradation of all station batteries.

The batteries

exhibited flaking of the cell plates and flaking of the plate's hook area where

the plates connect to the cell posts.

Although the licensee performed visual

inspections that included examination of the electrolyte level and accumulation

of sediment in the bottom of the cell, the severe flaking went unnoticed.

The

deteriorated cells were of the Plant6 design and over 15 years old.

The

batteries were expected to last about 20 years and an inspection by the battery

vendor 1 year earlier did not reveal abnormal degradation.

Subsequent NRC

inspections related to the cell-to-cell spacing and cell-to-rack spacing also

revealed that the batteries were not installed in accordance with the battery

vendor's seismic qualification recommendations.

As a result of the flaking, the battery vendor advised the licensee that the batteries at Rancho Seco

should be replaced and the licensee is now in the process of replacing the

batteries.

On April 16, 1986, North Anna Unit 2 declared three out of four station batteries

inoperable.

The specific gravities in the pilot cells of the affected batteries

were found below the technical specification limit.

In two of the batteries, approximately half of the cells had specific gravities that were out of

specification.

The cause was attributed to the inadequate float voltage.

These three batteries had recently been replaced with a different make and

model that required a different float voltage.

The corrective action included

readjusting the float voltage and applying an equalizing charge to the batteries.

8605130028

.IN 86-37 May 16, 1986 Discussion:

Although the batteries at Rancho Seco passed a duty cycle discharge test, this

has little relevance to the ability of the batteries to survive a seismic event

which could cause mechanical failure of internal connections weakened by

flaking.

The NRC has sponsored a series of tests of the seismic response of

naturally aged nuclear station safety-related batteries.

One of these tests

concluded that while case cracks were propagated and leaks were observed in the

propagation tests at high g-levels, it appears that this failure mechanism is

less significant than failures of the interface between the bus-bar and post.

(See NUREG/CR-3923, SAND84-1737, "Test Series 1: Seismic-Fragility Tests of

Naturally-Aged Class lE Gould NCX-2250 Battery Cells".) Although the type of

cells in this test were different than those that experienced severe flaking at

Rancho Seco, the test results suggest the importance of examining the internal

connection between the plates, the bus-bar, and post.

The event at North Anna demonstrates the need for continuing attention to the

detailed requirements for station batteries.

Other IE information notices on problems related to batteries include:

Number

Title

Date of Issuance

85-74 Station Battery Problems

August 29, 1985

84-83 Various Battery Problems

November 19, 1984

83-11 Possible Seismic Vulnerability of Old Lead

March 14, 1983

Storage Batteries

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

,Director

Divisio

f Emergency Preparedness

and Engineering Response

Eric W. Weiss, IE

(301) 492-9005 Attachment:

Attachment 1

IN 86-37

May 16, 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

86-36

Change In NRC Practice

Regarding Issuance Of

Confirming Letters To

Principal Contractors

5/16/86

86-35 Fire In Compressible Material 5/15/86

At Dresden Unit 3

86-34

86-33

86-32

Improper Assembly, Material

Selection, And Test Of Valves

And Their Actuators

Information For Licensee

Regarding The Chernobyl

Nuclear Plant Accident

Request For Collection Of

Licensee Radioactivity

Measurements Attributed To

The Chernobyl Nuclear Plant

Accident

Unauthorized Transfer and

Loss of Control of

Industrial Nuclear Gauges

Design Limitations of

Gaseous Effluent Monitoring

Systems

Effects of Changing Valve

Motor-Operator Switch

Settings

5/13/86

5/6/86

5/2/86

5/6/86

4/29/86

4/25/86

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

Fuel cycle licensees

and Priority 1 material

licensees

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or a CP

All power reactor

facilities holding

an OL or a CP

All power reactor

facilities holding

an OL or a CP

86-31

86-30

86-29

86-28

4/28/86 OL = Operating License

CP = Construction Permit