ML20083L975

Part 21 Rept Re Failure of Circuit Breakers During Environ Testing.Test Results Indicate That Temp Sensitivity Problem May Be Generic to All Ite Imperial Corp thermal-magnetic Circuit Breakers Calibr for 40 C Svc

ML20083L975
Person / Time
Site:	Hatch, Monticello, Nine Mile Point, Palo Verde, Fermi, Byron, Limerick, Clinton, LaSalle, 05000000, Shoreham, Hartsville, Phipps Bend
Issue date:	05/27/1983
From:	Empey D ROCKWELL INTERNATIONAL CORP.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
REF-PT21-84-194-000 83ESG-3401, PT21-84-194, PT21-84-194-000, NUDOCS 8404170427
Download: ML20083L975 (6)

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4 Energy Systems Group Rockwell cJai == international JtN - Gl983 Telephone:(213) 341-1000 E l

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- TWX: 910-494-1237 ' + -

Telex: 181017 May 27,1983 In reply refer to 83ESG-3401 -

U.S. Nuclear Regulatory Commission Region IV i

@@b 611 Ryan Plaza Drive i Mg _ Q%  !

Arlington, Texas 76012 Attention: Mr. John Collins, Administrator Region IV s ""

References:

(1) ESG Letter 83ESG-1483 dated March 11, 1983, D. C. Empey to John Collins

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(2) ESG Letter 83ESG-3402 dated May 24, 1983, D. C. Empey to John Collins Gentidmen:

Subject:

Status Update on Report of Deviation (10 CFR 21)

Reference (1) provided information regarding failure of circuit breakers during environmental testing. This letter is to update status of our corrective efforts and to complete the listing of suspect model numbers.

Also, please note that Reference-(2) has expanded the problem to similar circuit breakers made by another manufacturer and essentially duplicates i

the corrective action stated herein.

Component Description a) ITE Imperial Corporation circuit breaker,100A frame, 600-Vac, o thermal-magnetic trip,1400 C calibration, EF series.

b) ITEImperialCorporation~gircuitbreaker,'100Aframe,600-Vac, thermal-magnetic trip, 40 C calibration, HE series.

c) ITE Imperial Corporation gircuit breaker,150A frame, 480-Vac, thermal-magnetic trip, 40 C calibration, EH series.

c d) ITE Imperial' Corporation circuit breaker, 225A frame, 600-Vac, I thermal-magnetic trip, 400C calibration, Part No. FJ3-B150.

e) ITE Imperial Corporation circuit breaker, 400A frame, 600-Vac, thermal-magnetic trip,-400 C calibration JL series.

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Rockwell 83ESG-3401 International May 27, 1983 Page 2 Test Results During the IEEE 323 Environmental Qualification Testing, an EF3-B015 thermal-magnetfccircuitbreakerfailedtoreset(close)thetest 0 circuit at 165 F with a relative hugidity of 97% (150 F circuit breaker ambient temperature plus 15 F margin; reference ESG Component Qualification Test Report N00lTR700020 and Wyle Laboratories Report NES 58481).

The circuit breaker provides 480-Vac power to various control devices in Rockwell International, Energy Systems Group (ESG), Hydrogen Recom-biners. The failure mode, described above, would prevent the operation of the control devices and cause the Hydrogen Recombiner to shut down.

On January 28, 1983, an attempt was made to repeat the test in which the EF3-B015 circuit breaker had failed. The retest, which was completed on January 31, 1983, ing posj ditions (i.e., high denranstrated relative humiditythat dur[95-100%,}-LOCA environment con-and high temperature 1690F,1650F base temperature plus0 4 F tolerance ), the circuit breaker will automatically trip without a load being applied. Further testing was performed to establish the temperature at which the circuit breaker would trip while carrying a normal electrical load. - The tests were conducted simulating the worse-case loading of 3.5A, as it is used in the Hatch and LaSalle BWR power plants which are now in operation. The circuit breaker failed to carry the 3.5A by tripping after 13 min at 140 F. At 1300 F, .the circuit breaker had not tripped after 239 hours0.00277 days <br />0.0664 hours <br />3.95172e-4 weeks <br />9.09395e-5 months <br /> and 55 min while carrying the 3.5A load. Based on engineering judgment; this time period is sufficient to have achieved circuit breaker tempera-ture rise stabilization and indicates that this load can be carried con-tinuously at this temperature for the required post-LOCA maximum operating duration of one year.

On March 3',1983, additional tests were performed on the EF3-B015 circuit.

breaker to simulate temperature and loading conditions as it is used in PWR power plants. The circuit breaker was. loaded to SA, with a 33A surge for 5 sec to simulate motor starting characteristics. Thegircuitbregker failed to carry the 33A' surge by tripping in 4.5 sec at 130 F. At 120 F, the circuit breaker had not tripped after 91 hours0.00105 days <br />0.0253 hours <br />1.50463e-4 weeks <br />3.46255e-5 months <br /> while carrying the con-tinuous load of SA (the 33A surge for 5 see was applied at the beginning of the test).

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A Rockwell 83ESG-3401 International May 24, 1983 Page 3 The results of the above tests indicated that a temperature sensitivity problem might be generic to all ITE thermal-magnetic circuit breakers calibrated for 40 C service. Therefore, a test program was established to test representative sizes and types of the ITE thermal-magnetic cir-cuit breakers used in the ESG Hydrogen Recombiners (the circuit breakers actually used in the various recombiners are listed in the section entitled "Affected Plants"). A load current analysis was conducted to determine the worse-case loading for the various circuit breakers.

The objective of the test program was to establish the maximum circuit breaker ambient temperature at which the series of breakers could con-sistently carry the required load current. This temperature ss estab-lished to be 120 F.

For the PWR series of power consoles, a temperature rise within the con-sole due to component heating was measured to be 20 F at a console ambient temperature of 72 F. An equivalent rise is estimated for the BWR power consoles due to similarities in design.

The 20 F compartment temperature rise would limit both the BWR and PWR power console external ambient temperature to 100 F for reliable circuit breaker operation.

An investigation was conducted to evaluate replacement devices for the thermal-magnetic circuit breakers. Tests were conducted on representa-tive sizes 0of magnetic (only) trip cirguit breakers to temperatures of 1950F (150 F operating ambient plus 30 F compartment temperature rise (conservative) plus 150 F margin). Verification of operation included both the ability to continuously carry a current load and the ability to trip for simulated fault conditions. The ability to remain0 closed with no load current when subjected to a temperature of 212 F for six hours and then carry load at 195 F temperature was also verified.

In addition, analysis indicates that slow-blow fuses, with proper tem-perature and time derating, are also acceptable replacement devices for the thermal-magnetic circuit breakers.

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i 4k Rockwell 83ESG-3401 International May 24,1983 Page 4 Affected Plants NRC Licensed - 4 Customer Name Facility G.0. Part No. & Notes Detroit Edison Fermi 2 NPS 4056 EF3-B015 2 2 FJ3-B150 2 Long Island Shoreham 1 NPS 4093 EF3-8015 4 2 Lighting Co. EF3-B070 2 FJ3-B150 2 I 4 2 Philadelphia Limerick 182 NPS 4097 HE2-B015 Electric Co. HE3-8010 4 HE3-8030 4 Georgia Power Co. Edwin I. Hatch 2 4154 EF3-B015 4 2, 5 NPS FJ3-B150 2 Niagara Mohawk Nine Mile Point 4193 EF3-8015 4 2 Power Corp. 2 NPS FJ3-B150 2 Commonwealth :LaSalle County 4198' EF3-8015 4 2, 5 Edison 182 NPS FJ3-B150 2 I 2 ' 2, 5 Northern States- Monticello 4377 HE2-B015

'HE3-8015 2 Power Co.

HE3-8050 2' JL3-B175 2 JL3-B225 2 I 2 3 Arizona Public Palo Verde 4160 EF2-B015 Service Co. 1, 2, & 3 NPS EF3-8015 2 EF3-B020 2 EF3-8050 2 EF3-B100 2 a__-___

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Rockwell International 83ESG3401 May 27, 1983 Page 5 NRC Licensed Customer Name Facility G.O. Part No. Qty 4 Notes 1

Tennessee Valley Hartsville & 4210 EF2-B015 4 3 Authority Phipps Bend NPS EF3-B015 4 EF3-B020 4 EF3-8070 4 EF3-B100 4 1

Illinois Power Co. Clinton 1&2 NPS 4245 EF2-B015 2 3 EF3-8015 2 EF3-8020 2 EF3-8070 2 EF3-B100 2 1

Commonwealth Byron NPS 4260 EF2-B015 2 3 Edison EF3-8015 2 EF3-B020 2 EF3-8070 2 EF3-B100 2 ITwo-pole breaker in a three-pole frame _(the center pole is not used)-

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, Boiling. Water Reactor Plant (BWR) 3 Pressurized Water Reactor Plant (PWR)'or BWR MARK-III-4 Quantity does not include spares 5

0perating plants (as of February 1%3)

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83ESG3401 '

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May 27, 1983 . i Page 6 ',

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Corrective Action /Coninents , s Specific magnetic breakers have now been identified to replace the the#rmo- i t.;

magnetic breakers. Letters have been sent to the plant operators defining '

the replacement parts which may be used of the power cabinet external ambient temperature is determined to exceed 1000F. '(NOTE: The previous interim corrective action identified for operating plants way to bypass the circuit breakers with wire jumpers. This previous action should be superseded as noted above.)

If you require further information or clarification, please call me at (213) 700-3926.

Very truly yours, s--

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D. C.' Empey_

Director Quality Assurance cc: Director, Office of Inspection and Enforcement (3)

U.S. Nuclear Regulatory Commission Washington .DC 20555 e