ML20077E212
| ML20077E212 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 07/22/1983 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 23741, 83-05-1, 83-5-1, NUDOCS 8307280191 | |
| Download: ML20077E212 (6) | |
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CODSumBIS P0Wer
.,,,,,,,m hh Vice President - Projects, Engineering and Construction General offices: 1945 West Parnell ftoad, Jackson, MI 49201 * (517) 788-0453 July 22, 1983 83-05 #1 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND NUCLEAR C0 GENERATION PLANT -
DOCKET NOS 50-329 AND 50-330 BROWN BOVERI ELECTRIC HK CIRCUIT BREAKERS FILE:
0.4.9.77 SERIAL:
23741 On June 23, 1983, W R Bird of Consumers Power Company notifie'd J Harrison of your staff of a 50.55(e) reportable condition concerning absence of close-latch anti-shock spring in Brown Boveri Electric type HK circuit breakers, manufactured between June 1975 and June 1977. The subject switchgear may inadvertently close following spring charging. to this letter provides an analysis of the deficiency and the corrective actions taken with regard to this matter. This letter is our final report on this subject.
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l JWC/WRB/cd : MCAR-69, Final Report, dated July 11, 1983 CC: Document Control Desk, NRC l
Washington, DC l
RJCook, NRC Resident Inspector Midland N'iclear Plant 8307280191 830722 J/jf A k7383 PDR ADOCK 05000329 s
eon OC0783-0020A-MP01
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2 Serial 23741 83-05 #1 CC: CBechhoefer, ASLB Panel LBernabei, CAP FPCowan, ASLB Panel JHarbour, ASLB Panel AS&L Appeal Panel M'icherry, Esq MSinclair BStamiris CRStephens, USNRC WDPaton, Esq USNRC FJKelley, Esq. Attorney General j
SHFreeman, Esq, Asst Attorney General WHMarshall
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GJMerritt, Esq TNK&J INPO Records Center Great Lakes QA Managers OC0783-0020A-MP01
I21551 121578
Subject:
MCAR 69 (issued 6/24/83)
Absence of close-latch anti-shock spring in Brown Boveri Electric type HK circuit breakers, manufactured between June 1975 and June 1977.
Pinal Report:
Date:
July 11, 1983 Project:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Int roduction This report provides the status and the course of corrective action required pursuant to MCAR 69.
Description of Deficiency Brown Boveri Electric type HK circuit breakers manuf actured between June 1975 and June 1977, could be subject to inadvertent closing following spring charging due to the absence of a close-latch anti-shock spring in these breakers.
Summary of Investigation and Historical Background i
This deficiency was identified and documented in Brown Boveri Electric Incorporated, letter dated May 9,1983 (Attachment 1).
All Brown Boveri Class 1E circuit breakers used in the Midland plant are type HK.
These include breakers manuf actured prior to June 1977, i
Analysis of Safety Implication The inadvertent closing of the breakers can compromise the safety of operations at Midland plant following an undervoltage load shedding, if it were to occur in one of the Class lE feeder breakers or in the Class 1E incoming breaker. Depending on the timing of occurrence, this maloperation can lead to out-of-sequence diesel loading or paralleling of the lE/non-1E loads on the diesel generator or prevent closing of the diesel generator breaker.
The out-of-sequence diesel loading or paralleling of the lE/non-lE loads may compromise the diesel generator's capability to start and accelerate engiaeered safety features and forced shutdown loads te rated speed in the time f rame and sequence committed to in the Midland FSAR, Section 8.3.1.1,3.
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'""* '" 1"t**"it **"* * "d Infrequent problem, according to Brown Boveri. This condition was experienced on one out of approximately 150 HK circuit breakars.
Therefore, even though the inadvertent closing of the breaker can compromise the safety of operations, the probability of its occurrence is remote.
Probable Cauee The cause of this deficiency is the absence of the close-latch anti-shock spring in the EK breakers manufactured between June 1975, and June 1977.
Brown Boveri has stated that the close-latch anti-shock spring was omitted from the circuit breakers manufactured between June 1975, and June 1977, because the lack of occurrences of slipping latches did not warrant its continued use.
Corrective Action The corrective action to resolve this MCAR are as follows:
1.
Log the procedure for installation of close-latch anti-shock spring as an addendum to the instruction manual under purchase order 7220-E-205 (
Reference:
Bechtel Vendor Print 7220-E-205-207). All the Class 1E 4.16KV breakers in Midland are supplied by Brown Boveri, under purchase order 7220-E-205.
2.
Engineering to verify the date of manufacture of the Midland Class 1E HK circuit breakere listed in Attachment 2.
3.
Engineering to revise documents G-33(Q)(Specification - General Quality Assurance Requirements for Q-Listed Bulk Materials / Shelf Items Listing and Special Service Orders) and E-63(Q) (Electrical Field Purchase Devices) to include the close-latch anti-shock spring and cotter pins as items to be procured by field.
l 4
Based on the results of Corrective Action Ites 2, engineering to generate a DCP (Design Change Package) to add the close-latch I
anti-shock spring in all applicable class IE 4160 Volt circuit breake rs.
Corrective Actions 1-4 are forecasted to be complete by 8/24/83.
Reportability Based on the safety implications, this deficiency is considered reportable in accordance with Title 10 of the code of Federal Regulation, Part 50.55(e).
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l2155i MCAR 69 j2l$[g Page 3 Submitted by:
J.G. Kovach Electrical Group Supervisor Approved by:
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.M. Hughes Project Engineer Concurrence by:
R.L. Castleberry g
Electrical Chief Concurrence by:
E.B. Smith Engineering Manager Concurrence by:
C' d de r M.A.Dietrph Project Quality Assurance Engineer d/hl 062803
Attachment:
1.
Brown Boveri Electric, Inc. Letter to Bechtel, 5/9/83 (Com 115025) 2.
List of Class lE - 4160V Breakers supplied by Brown Boveri and manufactured prior to June 1977.
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$BC Brown Bovsri Electric,Inc.
- t-enowu sovam Marufacturer of I-T-E Electrical Power Equiprmmt l2l5fk0020 liging May 9, 1983 Bechtel Power Corporation P.O. Box 1000 Ann Arbor, MI 48106 ATTENTION:
Mr. J. A. Rutgers Project Manager
SUBJECT:
P.O. 7220-E-205-AC Bechtel/ Consumers Power (Midland)
. Metal Clad Switchgear S.O. 33-50382
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REFERENCE:
Limerick Generating Station 10CFR50.55(e) Report Dated April 28, 1983 Brown Boveri Electr'ic Close Latch Anti-Shock Spring for Medium Voltage Circuit Breakers GENTLEMEN:
Enclosed you will find copy of letter with attachments sent to the U.S. Nuclear Regulatory Commission dated April 28, 1983.
Our records indicate that the Type HK circuit breakers supplied on x
subject purchase ' order were supplied prior to June 1977.
- Regards, BROWN BOVERI ELECTRIC, INC.
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I. Jack Fahlen Executive Sales Engineer IJF/baf Enclosures cc:
E.M. Hughes - Bechtel (3131 856 4333 M200 Orehard 1.ake Itood. Sedte 110, Farm 4p Hills MI 48018 e
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office Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555 7
Reference:
Limerick Cenerating Station Philadelphia Electric Company Significant Deficiency Report No. 74 Dated March 24. 1983
Dear Mr. Stallo:
This is a follow-up report to an interish 10CTR50.55(e) report filed by the Philadelphia Electric Company with regard to a potential deficiency in 5EK switchgear supplied to the Linerick Generating Station by 3rt..n Boveri Ilectric.
This report was filed with the Office of Inspection & Inforcement, Region I.
j The report stated, "During pre-operational testing, one breaker inadvertently closed following completien of the spring charging and, two others spontane-ously and continuously closed and tripped following the spring charging cycle." The circuit breakers were returned to Brown Boveri Electric for evaluation of the reported problems. This evaluation revealed that the
.second problem, wherein it was reported that the circuit breakers closed and tripped spontaneously and continuously following the spring charging cycle could not be duplicated.
This condition can occur if the racking screw is not properly positioned in the " connected", " test" or " disconnected" position.
This second reported condition was deter =ined not to be a problem.
The first condition wherein it was reported that the circuit breaker inadver-tantly closed following completion of the spring charging was determined to
. be an intermittent problem on this one circuit breaker. The condition was corrected by adding a light apring to the close latch in the circuit breaker operating nr.chanism. The addition of this spring forces the clearances in the close-latch and associated linkages to be taken up in one direction.
This reduces the shock from the latch and linkages so that when the close j
latch roller, which is part of the cam assembly, is driven by the closing springs at the end of the charging cycle hits against the close latch, the latch is held and does not slip.
The sane basic operating mechanism is used on all BBE EK circuit breakers.
This includes the 5HK, 7.5BX,15HK and the 38HKV circuit breakers. The HK circuit breakers have been in production sinc.e approximately 1961.
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ns,rererv ... 33C Brown Boveri Electric Inc. i . m som s, i i 0 9 nr. victor steyg,;97 8 Ii5025 April 28,1983 Page 2 I the early 38EK7 circuit breakers which first went into production in 1973 experienced a slipping close latch which was thought to be caused by the heavier closing spring load. It was at this time that a light spring was added to the close latch of the BK operating mechanism. The spring is s. Adentified as Part No.,162374-A. Trom the time of initial production in 1961 up until 1873, this close latch anti-shock spring was not us.ed in the mechanism of the BK circuit breakers because there was no evidence of the close latches slipping. This spring was added to all RK circuit breaker mechanisms in October of 1973 and was included in production circuit breakers until June of 1975. In June of 1975, the spring was omitted on all 5, 7.5 and 15EK circuit breakers.b_ecause,the lack of occurrences of slipping latches did not warrant its continued use. Dn'ii of 1977 because of production changes, the spring, again, was added to all EK. circuit breakers. The spring has been used continuously on the 38EKV circuit breakers since 1973. ') The condition, vberein after the close spring charge, the circuit breaker closes unintentionally without initiation of the manual or electrical close operation, was experienced intermittently on one circuit breaker out of approximately 150 HK circuit breakers at the 1.imerick Generating Station. The condition, once experienced, may not occur again for 50 to 75 operations of the circuit breaker. Because of the infrequency of this condition occur-
- ing, the condition may go unnoticed by many users.
i r Instructions for the installation of the close latch anti-shock spring in the EK mechanism are contained in Brown Boveri Electric 13-8307. A copy of this instruction book is enclosed with this letter. Brown Boveri Ilectrie l vill not fy the users of HK circuit breakers of how to correct this condition if 13 1 ' { detected or to add the spring at the regularly scheduled maintenance ins ^ on. yllQ'4 v. . ovvau. Vic
- dent IWR/jn Inclosure
] cc: A. V. Boetticher l L'. I. Laubach E. W. Rhoads
- 1. E. Schmidt J. R. Silverio 4,n
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, *. t f-U 7fl.FFJP.)1J gSO D .1 s... mm, .a 19709 121578IiS025 s INSTRUCTIONS FOR INSTALLATION OF CLOSE LATCH ANTI-SHOCK SPRING IN HK MECHANISM (USED IN BREAKERS LESS THAN 1000 MYA) ..i IB-8307 Da./ s-BM !J4-3+! Browri Bdiveri Electric,Inc. ~ . -,. _ -,,..,,,...,,, _,,,, -,,. -. ~ . -ww m(+%lr. : A:a a - .M. w3. w. m-- AMy,~.mm, e _. ,+ - - - - ,.. m n ...... -...,.,...... - ~
B B C... .., U yc INSTRUCTIONS FOR INSTALLATION. _] i Si $.SjEgTC) KI-5HDCK SPRING IN HK MECHANISM g Ii5025 (USED IN BREAKERS LESS THAN 1000 MVA)
- 1. 'SENERAL 1.1 For general circuit breaker instructions refer to the appropriate Brown Boveri Instruction Bulletin.
1.2 The breaker must be removed from the switchboard. 1.3 Since the spring is to be installed on the underside of the breaker the breaker must either:
- 1. 3.1 Be lifted off the floor a sufficient distance, and supported for safety, so there is access to the underside.
1.3.2 Remove the barriers and are chutes so the breaker can be turned on its side or back for access to the underside. (See par. 3.3 before positioning the breaker on its back) 1.4 The breaker closing springs can be charged electrically or mechanically, but if charged electrically, the toggle switch should be turned off after each charge operation. 2. PARTS REQUIRED T . One (1) ' spring 162374-A' N One (1) cotter pin 53113-F6 3. INSTALLATION 3.1 Position the breaker for access to the underside per 1.3.1 on 1.3.2 above. ~ 3.2 Charge the closing springs and install the slow close bracket per the appropriate breaker instruction bulletin. Pull the manual close lever to discharge the springs to partially close the breaker.
- 3. 3 Manually trip the breaker. Check at the underside of the mechanism that the closing springs are "UP" so that the 1" dia. pin X 4 7/B" long with cotter pins at each end can be moved out to clear the close spring. ' tith the breaker in some positions, particularly on its back, the crank at the hex. shaft will sometimes rotate too far when the manual trip is made af.er the slow close which p'revents the 1" dia. pin from clearing the close spring If this condition exists, see 3.4.
3.4 Do this operation only if the 1" dia. pin will not clear the close spring as described in 3.3. Repeat the slow close operation but before pushing the manual trip an approximately 3/4 X 1 X 9 in. long wood block should be temporarily installed to prevent overtravel of the closing springs. This I block is placed vertically, between the truck and the closing spring crank, the motor side of the breaker, and taped temporarily to hold in place. The springs will now hold in the "UP" position when the breaker is manually trip Make sure to remove the wood block after installing the close latch anti- .) shock spring. j Brown Boveri Electric, Inc. Page 2 of : met:mm%wm+ms;&xw-nwgg;%ma.y=a-= ; ; ;; ; ;.: :..
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- .z T-1i5025 12l578 3.5 Viewing the mechanism from the rear. remove the right (motor side) side cotter pin in the 1" dia. X 4 7/8" long pin.
Tap the pin lightly toward the left approximately 1 1/2" until the 13/16 long X 1 1/8 dia. bushing on the pin can be removed. 3.6 Install the close latch anti-shock spring with the spring hook toward the rear of the breaker, the "L" shaped end of the spring on the top of the 3/4 dia. X 4 7/8 long pin with the 15/8 long spring end toward the motor side and the coil spring over the 13/S dia. hub of the close latch. The final step is to push the hook end of the spring up and toward the left'to hook over the 1/4" wide close latch. 3.7 While holding the 13/16 long bushing in place, tap the 1" dia. pin.back to its original position. Install a new cotter pin. 3.8 Remove the wood block if it was installed per par. 3.4. 3.g Complete the slow close operation by completing the manual charge operation. Remove the slow close bracket. 3.10 Close and trip the breaker several times to check its operation. 3.11 Reposition the breaker on the flo'or in its normal position. 3.12 If removed, reinstall the are chutes and barriers per the appropriate breaker instruction bulletin. - e o e ~ e......,0.... t Ct-a8 ta f a a-
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Attachunent 2 to MCAR 69 FIRL F.EPORT LIST OF C, LASS-IE HK. BRE.AKSA.5 121578 12l551 BREAKER NO. SU SYSTEM 1A05-501 1-PBA 1A05-502 1-PEA 1A05-503 0-EAA 1A05-505 1-NGE 1A05-506 1-PGA 1A05-507 1-BCA 1A05-508 1-ALA 1A05-510 1-EGA 1A05-512 1-BGC 1A06-601 1-PBB 1A06-602 1-PEB 1A06-603 0-EAA 1A06-605 1-PGB 1A06-606 1-BCA 1A06-607 1-ALA 1A06-609 1-EGA 1A06-611 1-BGC 2A05-501 2-PBA 2A05-502 2-PEA 2A05-503 0-RAA 2A05-505 2-NGE 2A05-506 2-PGA 2A05-507 2-BCA 2A05-508 2-ALA 2A05-510 2-ZGA 2A05-512 2-BGC 2A06-601 2-PBB 2A06-602 2-PEB 2A06-603 0-EAA 2A06-605 2-PGB 2A06-606 2-ALA 2A06-608 2-BCA 2A06-610 2-BGC 2A06-611 2-EGA 1A05-511 1-BGC 1A06-612 1-NGP 2A05-511 2-BGC 2A06-612 2-NGP ] .c,,n, m.,,..,,, -,- - -.. _}}