Information Notice 1985-09, Isolation Transfer Switches and Post-Fire Shutdown Capability

Isolation Transfer Switches and Post-Fire Shutdown Capability

ML031180654
Person / Time
Site:	Beaver Valley, Millstone, Hatch, 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, 05000262, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	01/31/1985
From:	Jordan E NRC/IE
To:
References
IN-85-009, NUDOCS 8501300138
Download: ML031180654 (3)

SSINS No.: 6835 IN 85-09

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

January 31, 1985

IE INFORMATION NOTICE NO. 85-09:

ISOLATION TRANSFER SWITCHES AND POST-FIRE

Addressees

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

construction permit (CP).

Purpose

This information notice is to alert recipients of potential deficiencies in the

electrical design of isolation transfer switches installed outside the control

room at many nuclear power plants. The transfer switches provide electrical

isolation of certain shutdown circuits from the control room and other essen- tial fire areas during post-fire accident conditions. It is expected that

recipients will review the information for applicability to their facilities

and consider actions, 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

During a recent NRC fire protection inspection at the Wolf Creek facility, it

was discovered that a fire in the control room could disable the operation of

the plant's alternate shutdown system.

Isolation transfer switches of certain

hot shutdown systems would have to be transferred to the alternate or isolated

position before fire damage occurred to the control power circuits of several

essential pumps and motor-operated valves at this facility. If the fire damage

occurred before the switchover, fuses might blow at the motor control centers

or local panels and require replacements to make the affected systems/components

operable. This situation existed because the transfer scheme depended on the

existing set of fuses in the affected circuit and did not include redundant

fuses in all of the alternate shutdown system circuits. For most of the trans- fer switches, the situation would not cause a problem because the desired

effect after isolation is the deenergization of power.

In instances where the

system/component has to be operable or where operation might be required to

override a spurious actuation of a component (such as a motor-operated valve),

replacement of fuses may have become necessary. In such cases, troubleshooting/

repair would be required to achieve or maintain hot shutdown.

8501300138

IN 85-09 January 31, 1985 Discussion:

At the Wolf Creek facility, where the concern was discovered, the transfer

switches at the remote shutdown panel had redundant fusing. The only transfer

switches identified as a concern were those at other local stations that mainly

involve support systems operability or correction of spurious operations.-The

facility is either modifying existing switches or installing new switches for

certain components so that redundant fusing will exist with a new (different)

set of fuses switched into the circuit when the switch is placed in the isolat- ed mode.

Alternate shutdown procedures also are being revised so that shutdown

could be achieved under fire conditions which result in immediate evacuation of

the control room and control room circuit damage that causes maloperation of

equipment prior to isolation outside the control room.

This situation may exist at other facilities and may involve the shutdown panel

and other local stations that are needed for alternate shutdown capability.

This could include the switches and other circuits on the alternate/remote

shutdown panel.

Operability of the hot shutdown systems, including the ability

to overcome a fire or fire suppresant induced maloperation of hot shutdown

equipment and the plant's power distribution system, must exist without re- pairs, including replacement of fuses.Section III.G.1 of Appendix R to 10 CFR

50 addresses fire protection of safe shutdown capability. Meeting this

requirement for the affected circuits will ensure that redundant fuses are part

of the transfer schemes.

_

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

However, if you have any questions regarding this notice, please contact the

Regional Administrator of the appropriate NRC regional office or the technical

contact listed below.

w A L

anD rector

Divisi

of Emergency Preparedness

and Engineering Response

W. T. LeFave, NRR

(301)492-9470

V. D. Thomas, IE

(301)492-4755 Attachment: List of Recently Issued IE Information.Notices

Attachment

IN 85-09

January 31, 1985

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

85-08

85-07

85-06

Industry Experience On

Certain Materials Used In

Safety-Related Equipment

Contaminated Radiography

Source Shipments

Contamination of Breathing

Air Systems

Pipe Whip Restraints

Inadequate Management Of

Security Response Drills

1/30/85

1/29/85

1/23/85

1/23/85

1/17/85

All power reactor

facilities holding

an OL or CP

All NRC licensees

authorized to

possess industrial

radiography sources

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

85-05

85-04

85-03 Separation Of Primary Reactor 1/15/85

Coolant Pump Shaft And

Impeller

All power reactor

facilities ,holding

an OL or CP, & fuel

fabrication & pro- cessing facilities

All pressurized water

power reactor

facilities holding an

OL or CP

All power reactor

facilities holding

an OL or CP

All material licensees

possessing irradiators

that are not self- shielded and contain

more than 10,000

curies of radioactive

material

85-02

Improper Installation And

Testing Of Differential

Pressure Transmitters

Continuous Supervision Of

Irradiators

1/15/85

1/10/85

85-01 OL = Operating License

CP = Construction Permit