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, Three Mile Island, 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
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: DEGRADATION OF STATION BATTERIES

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

Office of Inspection and Enforcement

Eric W. Weiss, IE

(301) 492-9005 Attachment: List of Recently Issued IE Information Notices

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 5/16/86 All power reactor

Regarding Issuance Of facilities holding

Confirming Letters To an OL or CP

Principal Contractors

86-35 Fire In Compressible Material 5/15/86 All power reactor

At Dresden Unit 3 facilities holding

an OL or CP

86-34 Improper Assembly, Material 5/13/86 All power reactor

Selection, And Test Of Valves facilities holding

And Their Actuators an OL or CP

86-33 Information For Licensee 5/6/86 Fuel cycle licensees

Regarding The Chernobyl and Priority 1 material

Nuclear Plant Accident licensees

86-32 Request For Collection Of 5/2/86 All power reactor

Licensee Radioactivity facilities holding

Measurements Attributed To an OL or CP

The Chernobyl Nuclear Plant

Accident

86-31 Unauthorized Transfer and 5/6/86 All power reactor

Loss of Control of facilities holding

Industrial Nuclear Gauges an OL or a CP

86-30 Design Limitations of 4/29/86 All power reactor

Gaseous Effluent Monitoring facilities holding

Systems an OL or a CP

86-29 Effects of Changing Valve 4/25/86 All power reactor

Motor-Operator Switch facilities holding

Settings an OL or a CP

86-28 4/28/86 OL = Operating License

CP = Construction Permit