SNRC-1024, Submits Results of Actions Taken to Comply W/Requirements of IE Bulletin 83-08 Re Electrical Circuit Breakers W/Undervoltage Trip Feature in Use in safety-related Applications Other than Reactor Trip Sys

Submits Results of Actions Taken to Comply W/Requirements of IE Bulletin 83-08 Re Electrical Circuit Breakers W/Undervoltage Trip Feature in Use in safety-related Applications Other than Reactor Trip Sys

ML20083R891
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	04/16/1984
From:	Mccaffrey B LONG ISLAND LIGHTING CO.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-83-08, IEB-83-8, SNRC-1024, NUDOCS 8404240349
Download: ML20083R891 (7)

Text

,g .%*

pm,_-~..~m; LONG ISLAND LIGHTING COMPANY M *.) SHOREHAM NUCLEAR POWER STATION hewwm,wwwwr P.O. BOX 618, NORTH COUNTRY ROAD

• WADING RIVER, N.Y.11792 April 16, 1984 SNRC-1024 Dr. Thomas E. Murley Regional Administrator U.S. Nuclear Regulatory Commission - Region I 631 Park Avenue King of Prussia, PA 19406 I. E. Bulletin No. 83-08:

Electrical Circuit Breakers with an Undervoltage Trip Feature In Use In Safety-Related Applications Other Than the Reactor Trip System Shoreham Nuclear Power Station - Unit 1 Docket No. 50-322

Dear Dr. Murley:

LILCO hereby submits the.results of our actions taken to comply with the requirements of I.E. Bulletin 83-08. 'These actions are prescribed on pages 3 and 4 of the subject bulletin and our response corresponds item by item to these as follows:

1. LILCO's numerous reviews concluded that there are no Westinghouse type DB, Westinghouse type DS, or General Electric type AK-2 circuit breakers with Under Voltage Trip Attachments (UVTA), as discussed in I.E. Bulletins 83-01 and 83-04, utilized in the Shoreham Nuclear Power Station.

However, we have identified that six (6) safety-related electrical circuit breakers, utilizing.an Under Voltage (UV) trip feature, are used in the Reactor Protection System (RPS).

As described in Section 7.2 of the SNPS FSAR, these six breakers are utilized in the RPS as an integral part of the Electrical Prctection Assembly (EPA). The EPA provides 8404240349 840416 PDR ADOCK 05000322 G PDR

((/

FC-893 5

'o

SNRC-1024 Page.2 redundant protection to.the Reactor Protection System, and

'olher essential circuits against overvoltage, undervoltage, and underfrequency. The -(EPA) circuit breakers have the '

following mark numbers: 'C71*BKR-002A & B, C71*BKR-003A & B and C71*BKR-004A & B. Additionally, we identified that two circuit breakers, utilizing an UV trip feature, are used in a nonsafety-related application. These two are the RPS motor generator output breakers. These eight electrical circuit breakers identified are manufactured by~the General Electric Company and are molded' case circuit breakers.

In addition to'the aforementioned RPS EPA electrical circuit breakers, LILCO, in addressing the concerns of I.E. Circular 81-12, reviewed all Category I breakers at Shoreham. This review concluded _that although no UE AK-2 circuit breakers are used, breakers utilizing an undervoltage trip feature are used in the normal and reserve supply breakers to the 4.16 KV emergency buses 101, 102 and 103. Additionally, the review concluded that these breakers and the 4.16 KV recirculation pump trip breakers utilize a dual trip coil design. Breaker-tripping is accomplished by a shunt trip. signal and each coil on these breakers is on a separately fused circuit with the capability for independent testing. Both the Shoreham Preventive Maintenance Program and Protective Relay Trip Operational Tests include steps to independently test both trip coils on duel coil breakers. The actions LILCO took to address the concerns of I.E. Circular 81-12 were' determined acceptable; and as described in section 4.1.12 of inspection report 50-322/83-08, the circular was closed.

2. (a) The RRS breakers identified in Item 1 by mark number are molded case type circuit breakers _ consisting of a thermal-magnetic trip element and operating _ mechanism with contacts _and interrupting means in a molded insulated case. The operating mechanism is quick-make,-

quick-break, and trip-free so that the contacts cannot be held closed against either a short circuit or'an.

overload. Utilizing input from1the system designerEand breaker manufacturer we have determined that _ the design margin available to open theLmolded case breakers is-as follows:

(1) 5-10 ounces _of force is required to release the~1atching mechanism. .The minimum and'

' maximum force available to release the-latching mechanism is 1.5 pounds.and 5.0 pounds, respectively.

• 1 w -

SNRC-1024 Page 3 (2) 2.5 pounds force is required to trip the breaker. 5 pounds force is available from the undervoltage device to trip the breaker.

Considering the fact that these electrical circuit 4

breakers are of a different design type than those discussed in the " Description of Circumstances" section of the subject bulletin, these design margins are adequate. Furthermore, problems encountered within either the UVTA or the trip bar latch assembly due to improper. lubrication, inadequate adjustment, excessive torque or excessive wear of moving parts do not necessarily apply to these breakers because the design of the molded case circuit breakers which are factory calibrated and sealed in a molded insulating case eliminates any tampering possibility and continuous maintenance.

(b) The EPA electrical circuit breakers (C71* BKR- 002A, 002B, 003A, 003B, 004A,& 004B) surveillance program is designed to comply with the requirements of technical specification 4,8.4.3 and is achieved using Shoreham station procedure SP-44.611.02, entitled "RPS ' EPA' Breaker Cal And Funct. Test". The above specified RPS electric power monitoring assemblies are determined operable by performing a Channel Functional Test, and by demonstrating the operability of overvoltage, undervoltage, and underfrequency protective instrumentation by performance of a channel calibration including simulated automatic actuation of the protective relays, tripping logic and output circuit breakers and verifying the technical specification set points.

(c) Our review of the operating experience with the circuit breakers identified in Item 1. above, concludes that Shoreham has not experienced any breaker malfunctions such as failure to trip or failure to close on demand.

However, the review did identify frequent tripping of the alternate power supply Electrical Protection Assembly (EPA). breakers (lC71*BKR-003A&003B) deenergizing the RPS bus, causing half scrams and valve closures. The cause of this problem was mainly attributed to voltage fluctuations on the alternate power supply bus. However, one breaker was found to be defective.

f

SNRC-1024 Page 4 The following is a list of the SNPS alternate power supply breaker experience:

DATE TIME DESCRIPTION 3-1-83 RPS Alternate supply EPA breakers 1C71*BKR-003A&B Tripped Frequently 4-05-83 1750 Lost RPS Alternate supply EPA breakers supplying RPS Bus A 4-07-83 0745 RPS Alt. supply EPA breaker 'A' Tripped. 1/2 Scram.

6-16-83 1835 RPS Alt. Supply EPA breakers Tripped 1910 RPS Alt. Supply EPA breakers Tripped

- Over-Voltag.

2026 RPS Alt. Supply EPA breakers Trippe1

- Over-Voltage 6-17-83 1755 RPS Alt. supply EPA breakers tripped due to High Voltage 7-07-83 1036 RPS Alt. supply tripped - Lost feed to RPS Bus "B" 8-05-83 1015 RPS Alt. Supply "B" breaker Tripped

- 1/2 Scram 1125 Same as above 1139 Same as above 8-16-83 0927 RPS Alt, supply EPA breakers tripped - Low Voltage - scram 1-13-84 0945 RPS Alt. supply breaker "A" tripped

- 1/2 Scram 1000 Same as above 1045 Same as above

.- ' SNRC-1024 Page 5 d) The following preventive and corrective measures have been taken at Shoreham:

A. The two interim measures taken to reduce the frequent tripping of the alternate supply EPA breakers (1C71*BKR-003A&003B) were to increase the time delay of the EPA breakers to the maximum.

setting, and to slightly increase the high voltage trip setpoint on these EPA breakers. These changes, however, were ineffective in eliminating the RPS breaker trips being experienced. A new measure which calls for the installation of a Voltage Regulator on the alternate supply is being implemented so that the RPS can-function as designed.

B. The undervoltage trip breaker IC71*BKR-003A, which was found to be defective, has been removed and replaced with a temporary 175A standard breaker.

The replacement breaker will be installed in accordance with maintenance work request MWR-84-0381. A Category I replacement breaker is already on site and we expect this work to be complete within the next two weeks.

C. The recommendations contained in the Independent Safety Engineering Group (ISEG) Report dated July 6, 1983, which was conducted as a result of the Salem ATWS Event, have been implemented to minimize the~ potential for breaker misoperation due to inadequate maintenance.

The subject recommendations were implemented as follows:

Shoreham Station Procedure SP12.009.03 " Report of Abnormal Conditions" insures that any.

unusual events are documented.

Shoreham Station Procedure.SP21.003.01

" Operations Report" is used by operations to evaluate ATWS conditions.

Shorehaa Station Procedure SP44.611.02 "RPS EPA Breaker Calibration and Functional Test" was written for the calibration and ~ functional testing of the six (6) EPA units (1C71*BKR-002A, 002B,-003A, 003B, 004A & 004B) utilized in the RPS system.

SNRC-1024 Page 6 D. Since the Salem breaker failure was attributed directly to improper maintenance, an ISEG review of the SNPS Preventive Maintenance (PM) Program was conducted to verify that all the breakers identified in Item 1. were scheduled for preventive maintenance.

The ISEG review concluded that all six (6) safety-related EPA breakers are included in the Station Procedure SP44.611.02. The two (2) nonsafety-related RPS Motor Generator set output breakers were identified during the ISEG review and are included in the Station Preventive Maintenance Program. Station Procedures SP12.015.01 entitled " Preventive Maintenance Program".SP37.006.03 " Molded Case Circuit Breakers Test", and SP 87.001.24 " Low-Voltage and DC Power Circuit Breakers", provide detailed instructions for station personnel to perform maintenance checks and tests on these electrical circuit breakers.

Also, because of the relative safety significance of these two electrical circuit breakers we are now evaluating the possibility of including them in SP 44.611.02 and thereby putting them under the technical specification surveillance envelop.

3. The requirements of this item do not apply to Shoreham.

4. The contents of this letter should satisfy the requirements of the written report sought by this item.

In order to help you evaluate the cost of implementing the requirements of this bulletin, we offer the following information:

.a) Our estimate of the time it took to perform the requested review and investigation needed to address the concerns of I. E. Bulletin 83-08, is 120 engineering hours.

b) Our estimate of the time spent to prepare this written report is 24 engineering hours.

Should you or any members of your staff have any questions regarding our response,to this bulletin please-do not hesitate to call my office.

Very truly yours,

[7 B. ]R. McCa Manager, Nu ear Compliance and Safety JB:lb cc: C. Petrone A

. - . .- -. - -~ _ _ - - - - - . .. .. _-

3 AFFIDAVIT 4

STATE OF NEW YORK )

ss:

COUNTY OF SUFFOLK )

BRIAN R. MCCAFFREY, being duly sworn, deposes and says I

< am the Manager, Nuclear Compliance and Safety for the Long Island Lighting Company. I have read I.E. Bulletin No. 83-08:

I " Electrical Circuit Breakers With An Undervoltage Trip Feature In Use In Safety-Related Applications Other Than The Reactor Trip System." I have also read this response which was prepared under my direction and dated April 16, 1984. The facts set forth in this response are based upon reports and information provided to me by the employees, agents and representatives of Long Island Lighting Company responsible for the activities described in said I.E. Bulletin and in said response. I believe the facts set forth in said responses are true, a

M _

Brian R. McCaffrey /

1 I Sworn to before me .this "

i //a day of[y4, / 1984 a takaLQ4 CONN!E-MARIA PARDO NOTARY PUBllc, see of r;en Ycre '

fio. 5XIS 10 Qu ?ihad in St.13:V Cour.N

%mmissia.1 Esc: ras 77Aug" jg