Information Notice 1985-63, Potential for Common-Mode Failure of Standby Gas Treatment System on Loss of Off-Site Power

Potential for Common-Mode Failure of Standby Gas Treatment System on Loss of Off-Site Power

ML031180232
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, 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:	07/25/1985
From:	Jordan E NRC/IE
To:
References
IN-85-063, NUDOCS 8507230389
Download: ML031180232 (3)

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SSINS No.: 6835 IN 85-63 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 July, 25, 1985 IE INFORMATION NOTICE NO. 85-63: POTENTIAL FOR COMMON-MODE FAILURE OF STANDBY

GAS TREATMENT SYSTEM ON LOSS OF OFF-SITE

POWER

Addressees

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

construction permit (CP).

Purpose

This information notice is being provided as a notification of a potentially

significant problem pertaining to the standby gas treatment system (SBGT).

This problem could result in the loss of all SBGT trains following a loss of

all off-site power. This supplements information provided in IE Information

Notices 83-25 and 84-81 on other SBGT problems. It is expected that recipients

will review the information for applicability to their facilities and consider

actions, if appropriate, to preclude a similar problem from occurring at their

facilities. However, suggestions contained in this information notice do not

constitute NRC requirements; therefore, no specific action or written response

is required.

Description of Circumstances

On May 14, 1985, Carolina Power and Light (CP&L) reported a logic design error

in the SBGT at Brunswick 1 and 2 which would result in the inoperability (i.e.,

failure to automatically start) of both trains of the system following a loss

of off-site power. Design of Brunswick's SBGT requires automatic initiation

when any of the following signals are received: high radiation in the reactor

building ventilation exhaust, high pressure in the drywell, or low reactor

water level. The system is designed to operate from either on-site or off-site

power sources. However, because of a design error, the instrument that senses

the SBGT heater temperature deenergizes a relay on loss of off-site power, seals in the signal, and prevents automatic initiation of SBGT until manually

reset.

At Brunswick, indications and reset are available in the control room. CP&L is

considering a modification to the circuit to install a time-delay relay to

allow time for the system to switch to on-site power. This effectively pro- vides automatic reset for situations where a cause for lockout does not exist.

8507230389

IN 85-63 July 25, 1985 Discussion:

The signals that trip SBGT are unique to each plant; however, automatic lock- outs are generally associated with the electric heaters. The events described

in IE Information Notices 83-25 and 84-81 provide examples where heater trips

have locked out systems and rendered them inoperable. Based on a review of

several licensee event reports, it appears that this design feature is fairly

common.

For designs such as Brunswick, with indication and reset in the control room, the operators might be able to diagnose and correct a problem. If indication

and reset are not available in the control room, significant difficulties might

be encountered if an accident requiring filtration were accompanied by a loss

of off-site power. In either event, however, the requirement for automatic

start generally necessitates the ability to start automatically even after a

loss of off-site power.

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.

A d -Ld.JordanmDirect or

Division of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Mary S. Wegner, IE

(301)492-4511 Attachment:

List of Recently Issued IE Information Notices

Attachment

IN 85-63 July 25, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-62 Backup Telephone Numbers to 7/23/85 All power reactor

the NRC Operations Center facilities holding

an OL Aind certain

fuel facilities

85-61 Misadministrations to Patients 7/22/85 All power reactor

Undergoing Thyroid Scans facilities holding

an OL and certain

fuel facilities

85-60 Defective Negative Pressure 7/17/85 All power reactor

Air-Purifying, Fuel Facepiece facilities holding

Respirators an OL or CP

85-59 Valve Stem Corrosion Failures 7/17/85 All power reactor

facilities holding

an OL or CP

85-58 Failure Of A General Electric 7/17/85 All power reactor

Type AK-2-25 Reactor Trip facilities designed

Breaker by B&W and CE holding

an OL or CP

85-57 Lost Iridium-192 Source 7/16/85 All power reactor

Resulting In The Death Of facilities holding

Eight Persons In Morocco an OL or CP; fuel

facilities; and

material licensees

85-56 Inadequate Environment 7/15/85 All power reactor

Control For Components And facilities holding

Systems In Extended Storage an OL or CP

Or Layup

85-55 Revised Emergency Exercise 7/15/85 All power reactor

Frequency Rule facilities holding

an OL or CP

85-54 Teletheraphy Unit Malfunction 7/15/85 All NRC licensees

authorized to use

teletheraphy units

OL = Operating License

CP = Construction Permit