Information Notice 1986-69, Spurious System Isolations Caused by the Panalarm Model 86 Thermocouple Monitor

Spurious System Isolations Caused by the Panalarm Model 86 Thermocouple Monitor

ML031250097
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, 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:	08/18/1986
From:	Jordan E NRC/IE
To:
References
IN-86-069, NUDOCS 8608130572
Download: ML031250097 (3)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 August 18, 1986 IE INFORMATION NOTICE NO. 86-69: SPURIOUS SYSTEM ISOLATIONS CAUSED BY THE

PANALARM MODEL 86 THERMOCOUPLE MONITOR

Addressees

All General Electric boiling water reactor facilities holding an operating

license or a construction permit.

Purpose

.

This notice is to alert recipients of a potentially significant problem involv- ing isolations of various BWR systems caused by spurious trips of the Panalarm

Model 86 thermocouple monitors, and of the actions taken by a licensee to

mitigate the problem. It is expected that recipients will review this informa- tion for applicability to their facilities and consider actions, if appropri- ate, 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

Licensee event reports (LERs) involving a spurious actuation of an isolation

system were recently compiled and evaluated in an NRC Office for Analysis and

Evaluation of Operational Data Report (AEOD/E604, March 14, 1986). Of the 31 LERs studied from various facilities between January 1984 and November 1985, only 1 event involved a valid trip of the thermocouple monitor resulting from a

high differential room temperature. Additional LERs related to spurious

isolation have been reported since the AEOD compilation. To date the monitor

trips have affected eight different plants and have caused spurious isolations

of reactor core isolation cooling (RCIC), high-pressure coolant injection

(HPCI), reactor water cleanup (RWCU), and main steam isolation valves.

On January 14, 1985, General Electric issued a Service Information Letter (SIL

No. 416) that provided recommended corrective actions for inadvertent isola- tions which occurred following loss and restoration of the ac power supply. In

addition to the problem addressed by the GE SIL, three recurring problems have

been identified from the LERs. The predominant source of the monitor trips

were caused by the operation of the monitor's "READ/SET" switch. Trips also

were attributed to electrical noise and nearby maintenance activities. The

spurious actuations have not always been repeatable by testing.

IN 86-69 August 18, 1986 Discussion:

The Panalarm Model 86 thermocouple monitor has been manufactured or distributed

by Ametek Panalarm Division, Scam Instrument Corporation, and Riley Panalarm

Company. It consists of three major components: (1) a point module, which

contains the appropriate thermocouple for each area monitored; (2) an optional

meter module, which permits reading the actual temperatures monitored; and (3)

a thermocouple monitor, which amplifies the output of the thermocouple. When

the temperature being monitored is in an alarm condition, the monitor can be

set to close relay contacts and initiate further action such as isolations or

provide annunciation. The actual monitoring function is performed continuously

and is independent of the operation of any controls. The indication depends on

the operation of a "READ/SET" switch which causes the outputs of each point

module to be indicated by the respective meter module. As stated above, the

transient caused by operation of this switch has been the most prevalent cause

of the monitor trips.

The Duane Arnold Energy Center, following spurious isolation events, has

installed a 1-second time delay in the steam leak detection circuitry for the

RWCU and is planning to install similar time delays in the HPCI and RCIC

circuits. The addition of a 1-second time delay appears to have been effective

at eliminating spurious isolations while allowing an actual alarm condition to

initiate isolation as designed. Duane Arnold Center verified that the addition

of a 1-second time delay between the monitor and isolation actuation would not

cause any valve closure times to exceed the assumptions of the design basis and

safety analysis of the various systems. The increase in system reliability and

reduction in challenges to the systems was considered by Duane Arnold Center to

result in a greater margin of safety.

GE has stated that additional information concerning increasing reliability of

the thermocouple monitor will be issued in the near future via the SIL system.

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

Divisi n/of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

James Stewart, IE

(301) 492-9061 Attachment: List of Recently Issued IE Information Notices

a

Attachment 1 IN 86-69 August 18, 1986 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

86-68 Stuck Control Rod 8/15/86 All BWR facilities

holding an OL or CP

86-67 Portable Moisture/Density 8/15/86 All NRC licensees

Gauges: Recent Incidents And authorized to possess, Common Violations Of Require- use, transport, and

ments For Use, Transportation, store sealed sources

And Storage

86-66 Potential For Failure Of 8/15/86 All power reactor

Replacement AC Coils Supplied facilities holding

By The Westinghouse Electric an OL or CP

Corporation For Use In Class

1E Motor Starters And

Contractors

86-65 Malfunctions Of ITT Barton 8/14/86 All power reactor

Model 580 Series Switches facilities holding

During Requalification Testing an OL or CP

86-64 Deficiencies In Upgrade 8/14/86 All power reactor

Programs For Plant Emergency facilities holding

Operating Procedures an OL or CP

86-63 Loss Of Safety Injection 8/6/86 All PWR facilities

Capability holding an OL or CP 4

86-62 Potential Problems In West- 7/31/86 All power reactor

inghouse Molded Case Circuit facilities holding

Breakers Equipped With A an OL or CP

Shunt Trip

86-61 Failure Of Auxiliary Feed- 7/28/86 All power reactor

water Manual Isolated Valve facilities holding

a CP

OL = Operating License

CP = Construction Permit