ML20084K244

Final Deficiency Rept Re Broken/Cracked Puffer Piston Rods in Model 5 Hk Breakers Mfg by Brown-Boveri.Initially Reported on 831213.Safety Evaluation Performed to Determine Impact on Safety of Operations.Maint Procedure Revised

ML20084K244
Person / Time
Site:	Oconee, Fermi, Midland, 05000000
Issue date:	03/30/1984
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084K247	List: ML20084K244 ML20084K269
References
28064, 83-13-#2, OL, OM, NUDOCS 8405110153
Download: ML20084K244 (7)

Text

{{#Wiki_filter:.. _. h$lb @ Consumers Power Company General offices: 1945 West Parnall Road, Jackson, MI 49201 * (517) 788-0550 March 30, 1984 83-13 #2 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND ENERGY CENTER PROJECT DOCKET NOS 50-329 AND 50-330 BROWN-BOVERI BROKEN / CRACKED PUFFER PISTON RODS FILE: 0.4.9.85 SERIAL: 28064

Reference:

J W Cook letter to J G Keppler, Same Subject, Serial 26661, dated January 12, 1984 On December 13, 1983 Consumers Power Company notified your staff of a potential 10CFR50.55(e) condition involving broken / cracked Puffer Piston Rods in Model 5 Hk breakers manufactured by Brovn-Boveri. This letter is a final 10CFR50.55(e) report. Further investigations have determined that this condition, if undiscovered, could have affected the safety of plant operations. The attachment to this letter describes the safety impact, the root cause, the scope of investigation and the controls imposed over remaining work activities. JWC/AHB/tr

Attachment:

MCAR-77, Final Report, dated March 16, 1984. CC: Document Control Desk, NRC Washington, DC RJCook, NRC Resident Inspector Midland Nuclear Plant DHood, USNRC Office cf NRR INPO Records Center APR 2 1984 8405110153 040330 PDR ADOCK 05000329 $d) OC0384-0033A-HP01 S PDR g\\

c. o 2 Serial 28064 83-13 #2 OM/0L SERVICE LIST Mr Frank J Kelley Atomic Safety & Licensing Attorney General of the Appeal Board State of Michigan U S Nuclear Regulatory Commission Ms Carole Steinberg Washington, DC 20555 Assistant Attorney General Environmental Protection Division Mr C R Stephens (3) 720 Law Building Chief, Docketing & Services Lansing, MI 48913 U S Nuclear Regulatory Commission Office of the Secretary Washington, DC 20555 Mr Myron M Cherry, Esq Suite 3700 Ms Mary Sinclair Three First National Plaza 5711 Summerset Street Chicago, IL 60602 Midland, MI 48640 Mr Wendell H Marshall Mr William D Paton, Esq RFD 10 Counsel for the NRC Staff Midland, MI 48640 U S Nuclear Regulatory Commission Washington, DC 20555 Mr Charles Bechhoefer, Esq Atomic Safety & Licensing Atomic Safety & Licensing Board Panel Board Panel U S Nuclear Regulatory Commission U S Nuclear Regulatory Commission East-West Towers, Room E-413 Washington, DC 20555 Bethesda, MD 20014 Ms Barbara Stamaris Dr Frederick P Cowan 5795 North River Road 6152 N Verde Trail Rt 3 Apt B-125 Freeland, MI 4c;23 Boca Raton, FL 33433 Dr Jerry Harbo.r Mr Fred C Williams Atomic Safety & Licensing Isham, Lincoln & Beale Board Panel 1120 Connecticut Ave, NW, Suite 840 U S Nuclear Regulatory Commission Washington, DC 20036 East-West Towers, Room E-454 Bethesda, MD 20014 Mr James E Brunner, Esq Consumers Power Company Mr M I Miller, Esq 212 West Michigan Avenue Isham, Lincoln & Beale Jackson, MI 49201 Three First National Plaza 52nd Floor Chicago, IL 60602 OCO384-0033A-MP01

o 3 Serial 28064 83-13 #2 Mr D F.Judd Babcock & Wilcox PO Box 1260 Mr John Demeester, Esq Lynchburg, VA 24505 Dow Chemical Building Michigan Division Mr Steve Gadler, Esq Midland MI 48640 2120 Carter Avenue St Paul, MN 55108 Ms Lynne Bernabei Government Accountability Project Mr P Robert Brown 1901 Q Street, NW Clark, Klein & Beaumont. Washington, DC 20009 1600 First Federal Bldg Woodward Ave Detroit, MI 48226 3/14/84 t I L l OC0384-0033A-MP01 L

Attachment to Serial 2806h l45368 Bechtel Associates Professional Corporation 83-13 #2 1 145475

SUBJECT:

MCAR 77 (issued 12/14/83) l Broken / Cracked Puffer Piston Rods in Type 5 HK Breakers Manufactured by Brown Boveri Between 1960 and 1980 [ t lFINALREPORT DATE: March 16, 1984 i l PROJECT: Consumers Power Company Midland Plant Units 1 and 2 l Bechtel Job 7220 1 i t i Introduction ) This report provides the status and course of action required pursuant to MCAR 77. l f -{ l ' Description of Deficiency I t l Brown Boveri Type 5 HK circuit breakers manufactured between 1960 and l 1980 may have broken / cracked puffer piston rods. l Bussnary of Investination and Historical Backaround [ i I This deficiency was identified by The Detroit Edison Company at the Fermi i nuclear plant and documented in a Brown Boveri letter to Bechtel dated i October 31, 1983 (com 133441) (Attachment 1). [ l I The Midland 4,160 V. Class II switadtgear uses Brown Boveri Type 5 HK l circuit breakers. All breakers (except breakers in cubicles 1A06-12 and l l 2A06-12) supplied for the Midland plant were manufactured between 1960 [ and 1980. I [ The following additional information was provided in the Brown Boveri Electric final report to the NRC dated November 29, 1983 (Attachment 3): 1,

1) Additional testing and analysis performed by Brown Boveri indicates f

that failures are due to material voids resulting from problems in processing the material. Brown Bovori has concluded that the relatively few processing problems that were experienced are random in nature. l

2) The actual number of failed (broken) puffer piston push rods that have been reported is less than 20.

The total number of puffer piston assemblies installed in Type 5HK circuit breakers since 1968 l 1s over 75,000. i 0505u

.\\ l f45368 Bechtel Associates Professional Corporation 145475 NCAR 77 I Final Report Page 2 The NRC published IE Information Notice 83-84 on the subject of cracked and broken piston rods in Brown Boveri Type 5 HK Breakers. The notice I sussnarized information provided in the Brown Boveri interim and final i i reports (see Attachments 1 and 3). Analysis of safety Implication The puffer piston rods (one for each pole of a breaker) assist extinction f of an are at low current values (below 1,000 amperes). If the puffer piston rods of a circuit breaker are broken, opening of the breaker may l i not interrupt the resulting arc. The presence of an are could lead to a l I path to ground resulting in a ground fault at the breaker, which could l trip out the entira switchgear and cause permanent damage to the bre ker [ with the broken rod. The safety-related ac loads, powered from this switchgear, may therefore be unable to perform their intended function Iuntilthebreakerwiththegroundfaultisremoved. l l { Root Cause l Brown Boveri's final report identifies the root cause of this problem as a nonuniform tool temperature used during the process of molding the puffer piston rods: the tool was operated while it was in the state of initial heatup for molding the part. This resulted in a failure to enhance the crystalline st:ucture, leading to material voids or nonhomogeneity, which caused local areas of high stress that retalted in } breakage. The problem was limited to puffer piston rods manufactured before 1980 that used a nylon material called Zytel 101. Since 1980, the parts have been manufactured with a toughened and reinforced material j identified as Nylafil. Brown Boveri's final report states that there is i no reason to suspect that these parts will be subject to cracking. Corrective Action The corrective actions to resolve this NCAR are as follows. l I

1) A safety evaluation was performed to determine the impact on safety of operations at the Midland plant, and was documented in Bechtel l

internal correspondence (Com 137410 December 16, 1983). l

2) Nonconformance Report (NCR) D-00005 was issued December 20, 1983, to I

identify and control this nonconforming condition. The Class 1E Type 5 HK breakers manufactured between 1960 and 1980 will be examined for broken / cracked puffer piston rods (see Attachment 2). Any t broken / cracked puffer piston rods found during the field inspection f t will be replaced. t

3) QAR RD0023 was issued for inclusion of puffer piston rod inspection

[ at normal maintenance intervals into the appropriate maintenance [ 0505u

? ~ Bechtel Associates Professional Corporation i t i45366 I45475 l MCAR 77 Final Report Page 3 procedure. The revised maintenance procedure will require inspection i of puffer piston rods made of Zytel 101 supplied on Class IE, 5 HK f 'ureakers manufactured between 1960 and 1980. This revision is scheduled to be complete by December 27, 1984. l 4. An investigation indicates that there are no other safety-related l breakers with siellar design and material supplied to Midland. Therefore, only Class 1E, 4,160 V breakers manufactured by Brown l Boveri (see Attachment 2) could be subject to the broken puffer piston rods concern. l \\ l Reportability [ l This was reported to the NRC on December 13, 1983, as a potentially l reportable 10 CFR 50.55(e) condition. i Submitted by: SQ<. E'.B. Poser Project Engineering Manager l [ Approved by: k%/ -t R.L. Castleberry l Chief Electrical Engine i f Approved by: Lt. l E.H. Smith ' [ Engineering Manager f I Concurrence by: l l M.A. Dietrich I i Midland Project Quality Assurance Engineer i k LY-JGE M /amc8(E) i f Attachments: 1. Brown Bover! Electric letter to Bechtel, 10/31/83 i (com 133441) l 2. List of Class 1E, 4,160 V Breakers Supplied by Brown Boveri and Manufactured Between 1960 and 1980 3. Brown Boveri Electric letter to NRC 1/10/84, enclosing l IE Information Notice 83-84 l t f 0505u

Arr^cumeur 1. T~O HCAR'l7 PINAL REPO RT 1BBC srown sovari siectric, inc. ( 5 $ ""* , BROW:e BOVERI Manufacturer of I-T-E Electrical Power Equipment 145475 145368 133441 October 31, 1983 Bechtel Power Corporation P.O. Box 1000 Ann Arbor, MI_ 48106 ATTENTION: Mr. Rutgers Project Manager

SUBJECT:

P.O. 7220-E-205-AC Bechtel/ Consumers (Midland) Metal Clad Switchgear S.O. 33-50382

REFERENCE:

Detroit Edison Company Enrico Fermi Generating Station CFR50.55 (E) Report Dated March 17, 1983 Brown Boveri Electric 5HK250/350, 1200/2000 amp Circuit Breakers - Cracked and Broken Puffer Piston Rods GENTLEMEN: Enclosed you will find a copy of a letter from Brown Boveri Electric, Inc. with attachments sent to the US Nuclear Regulatory Commission dated October 5, 1983.

Regards, BROWN BOVERI ELECTRIC, INC.

h. I. Jack Fahlen Executive Sales Engineer l IJF/baf Enclosures cc: E.M. Hughes - Bechtel i 38200 oM Lake Reed. 5 mite 110, Farmington H6lls, MI 48015 * (313) 866 4333 l

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Dear Mr. DeYoung:

On March 17, 1983 Detroit Edison Company (Farmi II) filed a 10CFR50.55(e) report with the NRC concerning some cracked and broken puffer piston rods in the Brown Boveri Electric 5EK 250/350,1200/2000A circuit breakers. l l Attached is an interim report on the 33E evaluation status to date on this condition. ) Based on the test results and other information available at this time the 3BE recommendation is to inspect for cracked or broken puffer piston push i rods at rmal maintenance intervals and to replace the puffer piston assemb1' this e dition is found. .I Y l .i s l... D. c ---. - i .tce President 6 l l DDD/ja t Attachment cc: A. E. Boetticher W. E. Laubach v.E. V..thoads-s L. E. Schmidt J. R. Silverio ~ ? W. Laudan. NRC I & E .l / mu. m % 3 rO f eJO #iL p - l e ~ SwMehem.e Syyte'EDMelon i Spdne House. PA 19477

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...i g'. - .~: r z.....-., INTER 2M ~a n S E CIRCUIT S w m t. 3 rurir.a PIST03 nrme . :. :.... n.. -. ...f.,. The purpose 'of this interim ieport is to suunarise the status of the evalu i ation to date and to provide a history regarding cracked / broken puffer piston rods (part No. 193642-3) La the Brown Boveri Electric S R 250/350,1200/2000A circuit breakars. ., g r !,L. Im January,1983, a report of some cracked /brokaa puffer piston rods at the ~ '*" Mohave Generating Station of Southern California Edison in Lauglin, Nevada was received. These circuit breakers are SE 350-1200A supplied on 8.0. 33-44107 and have been in operation since abc.ut 1970. The cracks / breakage of the puffer piston rods occurs at the operating pin hole. The conditions were 1 acted while performing an overhaul on the circuit breakers, with some twenty 1 (20) circuit breakers in Unit No.1 and twenty (20) in Unit No. 2, thus a total of 120 puffer pistons are in operation at this station. A total of eight (S) 3 puffer piston rods were found to be broken. The number of puffer piston rods ./ that were cracked is not known, however the user ordered a total of twenty (20) replacement parts. } The average ambient temperature at this station' la about 80*F. Temperature excursions normally vary between 35*F and 125*F, but extrenes to a low of +30'F and a high of 135*F have occurred. The humidity is normally between 10% and 15%. No more than one broken puffer piston rod per breaker was found during any inspection. } ', ~ A March 17, 1983 report received from Detroit Edison (Ferni) indicates that [ one (1) broken puffer piston rod and nine (9) cracked rods in 3R 3504200A t circuit breakers were found. These circuit breakers were manufactured in 1973 on 5.0. 33-47196 and the reported conditions were noted in a total of five (5) circuit breakars. No operation count was reported on these breakers. l A 33E service Engineering Report dated August,1983 identifies that some l SR 250-1200A and 2000A at the Salt River. project Navajo Generattag Station l mainufactured between 1972 and 1980 were awaked for puffer piston rod cracks. l There are approxilbately eighty4eiz (86) circuit breakers at this location. i some of which have over 10,000 operations. This inspection showed that there were so cracks or breakage in any of the puffer piston rods. The environ-( l mental conditions at this station are similar to those noted at the Mohave i Generating Station. l t ) 1 6 l I .,... - I - py Q*o ..+ 1 ~ a,e m.. hsis. m ss i a..,',

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. :: ~ ~ . 3... - .y .,-y "~ ne sEE circuit breakers have been la production since 1960 with essentially the same design configuration and materials used today. De puffer pistem tube was originau y made with 2ytel 101 unfilled material. h is material was used until 1980 when the vendor and material was thanged to Wylafil El-30-EM. puffer pistos rods of both the Zytel and Wylafil material have been subjected. to thermal aging tests with no significant degradation trend being meted af ter initial " drying out" of the nyles material. When humidified after less arposure 'at high temperature the material returns to essentially the same strength characteristics as when new. Dermany aged puffer pistes rods in the dry condition were subjected to endurance testing of ever 3000 operations..-----"- Buhsequent laspection of these items disclosed me aracking er damage to the puffer pisten rods. Three (3) puffer pistos rods with cracks were obtained from Detroit Edissa Fermi 2 station. These were subjected to mechanical endurance testing in a test breaker to investigate the tendency for existing cracks to progress inte failures. Af ter 1200 operations, the inspection indicated that the crache g did not propagate nor did any parts break. one of the puffer pistos rede for ,) this test was modified wherein the holes for the operating pin were redrilled in a smaller diameter to,. determine if this interference fit of the pin could result la a test failure. The inspection of this part upon the completion of the endurance test (1200 operations) indicated that cracks had met devel-i eyed. l A puffer piston la the SEK circuit breaker performs two functions. For low l current interruptions the puffer is needed to assist the magnetic forces to sove the are into the interrupting chamber. A puf fer pisten also provides a pneumatic cushion which reduces the shock forces imposed on the mechanism and current carrying parts on opening. For lower values of current, are inter-ruption could be adversely affected by failure of one puffer piston with failure to extinguish the arc. Mechanically, loss of a puffer could reduce the suaber of operations before maintenance would be necessary. BBE has never experienced a circuit breaker failure due to a broken puffer pistos red. At this time, the'3BE evaluation of data indicate that aging is not a likaly sause for the puffer piston rod cracks. Also. 33E testing and the sospling l Laspections conducted to date also ladicate that the tracking is not a l generia defect, 6 A. l r g _,m me n, -,_,wmm_ew__m ,-m

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~ Efforts are taJer way to obtain addittenal aged samples from the fleid and eessultations with other materials experts are planned. At the time of this i 1::teria report there is no clear explanation for the presence of puffer pistes red cracks og Fetwi 2. Inforination gathered to date also ladicates that no. wre than er.e.brokes ysffer piston roJ per breaker has been found at any imapec tier.. 321 is continuins its evaluation of this situation and will keep you advised of any significant findings. w. i 'Its Pht reconnendation at this time is to laspect for this condition at normal i maintansace intervals as.d to replace cracked or broken assemblies. The assembly palt sur.ber is 193989-;2. 1 N 4 l g e e} \\ t 8 \\

14S368 Att.en :t 2 ta nCA 77, ric:1 n., ort LIST OF CLASS lt 5 NE CIRCUIT BREAKERS IN MIDLAND I (MANUFACTUR$ $ g 1960-1980) Breaker Startup.81 stag Breaker Startup System 1A05-501 1-PSA 2A05-501 2-PBA 1A05-502 1-PEA 2A05-502 2-PEA 1A05-503 0-BAA 2A05-503 0-EAA 1A05-505 1-NGE 2A05-505 2-NGE i 1A05-506 1-PGA 2A05-506 2-PGA 1405-507 1-SCA 2A05-507 2-BCA 1A05-508 1-ALA 2A05-508 2-ALA i 1A05-510 1-BCA 2A05-510 2-EGA l 1A05-512 1-BOC 2A05-512 2-BGC i 1A06-601 1-PSB 2A06-601 2-P88 1A06-602 1-PBS 2A06-602 2-PBS 1A06-603 0-EAA 2A04-603 0-EAA 1A06-605 1-PG8 2A06-605 2-PG8 1A06-606 1-SCA 2A06-606 2-ALA 1A06-609 1-BOA 2A06-608 2-BCA 1A06-611 1-BOC 2A06-610 2-BGC 1A05-511 1-DOC 2A05-511 2-BGC 1A06-607 1-ALA 2A06-611 2-EGA l 1 l t 0$0$u

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--: EP.~ we's i. ':- ~-TF S r [. [$*N[M EOMNd5NdEEd$d5EM l Nuclear Distribution List r.om E. W. Rhoads Oe L.. Engineering

e January 10, 1984 4 :* 2-Spring House 5.: :-

NRC II INFORMATION NOTICE NO. 83 C:o es *: CRACKED AND BROKEN PUTTIR PISTON l RODS IN BROWN BOVERI SEK BREAKERS l i l Enclosed is a copy of the subject NRC Information Notice #83-84, which, except for a couple of misspellings, reflects our findings and recom-mandations on this subject. i Also enclose'd for your information is a copy of our last letter (Nov. 29, 1983) to the NRC on this matter, explaining the cause of the cracked or t broken piston rods in more detail. i It should be noted that the few random problems of broken or cracked piston rods have been attributed to vendor processing problems with the order material identified as Zytel. Only those parts that show cracks l or are broken need to be replaced. Zytel piston rods that are not cracked or broken may continue to be used. [ L Since this report has been sent to all nuclear facilities by the NRC there is no need to transmit this to your customers. [ l .d E. W. RHOADS [ 1 EWR/ja i Enclosure I ? i I t' e i i r ~. - - - -,,. - - -, -. , _ _ _ _ _ - - _ _ _ - _ _ _}}