United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9712190171



SIEMENS



                                        December 1, 1997



ABB Combustion Engineering Nuclear Operations

PO Box 500

2000 Day Hill Road

Windsor, CT 06095-0500



Attn: Jack R.  Buckholz



RE: Failed MDR Relays at Entergy Operations, Inc.



Jack,



ABB has forwarded three reports from Southwest Research Institute to

Siemens Electromechanical Components pertaining to three failed MDR-7032

"medium" relays at Entergy Operations, Inc.'s Waterford 3 Nuclear

Generating Station.  Included in these reports are an analysis and a

conclusion.  Siemens Electromechanical Components agrees with the

analysis contained in these reports, however, Siemens Electromechanical

Components has reached a different conclusion based on its own analysis

and testing.



Siemens Electromechanical Components performed a number of temperature

tests to determine if the Nye Nyogel 718B grease degrades for the

possible temperature operations of these types of devices.  Temperature

testing of bearings shows both bearings are approximately the same

temperature, A temperature test was conducted on the MDR-7068, the

highest wattage of the suspected relays.  With a 10% over voltage of 33.0

VDC, the bearing near the mounting base checked 58 Degrees C, and the

bearing at the contact end checked 59 Degrees C Nye Nyogel 718B grease,

is rated by the manufacturer for 260 Degrees C, The bearings operate 200

Degrees C below the manufacturer max rating.  A weight loss test of the

Nyogel grease is an on going test, After 696 hours at 150 Degrees C,

there was only 1.312% weight loss.



Siemens Electromechanical Components theory is the grease was

contaminated by silicon dioxide fibers.  To test this theory, relays were

built using contaminated grease (test samples) and uncontaminated grease

(control samples) in the bearings.  Relays were cycled for 162,000

operations then left energized continuously for 48 hours at 65 Degrees C,

The relays with uncontaminated grease still had fluid grease while the

units with contaminated grease was a thick paste.  The conclusions of

these test shows that Nyogel grease does not degrade and cause the relay

to bind.  The results clearly show that the contaminated grease Is the

root cause of the failure



                                                                   Page 1

Siemens Electromechanical Components, Inc.



200 South Richland Creek Drive          Tel 812 386-1000

Princeton, IN 47671-0001                Fax 812 386-2430



SIEMENS



Siemens Electromechanical Components did not analyze the failed relays at

Waterford 3 because these units were not submitted to us.  The amount of

contamination that was within the relays is not known.  Prior documented

history Return Material Evaluation number 34017 (attachment one) had 4

MDR-170-1 relays recalled from ABB due to contamination within the

relays, with date code of 9412.  These 4 relays were the total order

built for ABB.  The contamination contained silicon dioxide fibers from

contact ring insulator plates, flakes from the switch rings, and flakes

of the coil epoxy.  When silicon dioxide fiber is mixed in grease it

becomes very abrasive, similar to lapping compound.  This caused abnormal

wear particles from the shaft and bearings.  The grease then absorbs the

wear particles and becomes too stiff for the relay to operate.



Only the medium relays listed in attachment 2 are suspected to have this

problem.  There has been no reported failures on the small relays.  The

date codes of the suspected medium MDR relays are from 9317 to 9532.  The

reason 9317 is the suspected date codes is the start up date of the line

after moving from Princeton, IN to  Marion, KY.  Date code 9532 is the

initiation of a continuous improvement team.  The team formalized

housekeeping procedures and added an enclosed booth that isolated MDR

final assembly from general production area preventing contamination.

The relay listed in attachment 2 with the date codes 9317 to 9532 can be

returned to the factory for inspection.



Respectfully submitted,



Dick Market

Staff Technical Specialist

Product Engineering

Attachments:  RME #34017 and #34406, and Part list of Potential Affected

Devices.



XC:  Dan Smith, SEC

     Al Tessier, ABB

                                                            Page 2



Siemens Electromechanical Components, Inc.



200 South Richland Creek Drive     Tel 812 386-1000

Princeton, IN  47671-0001          Fax 812 386-2430



SIEMENS



                     PROBLEM SOLVING AND RESOLUTION

Problem No.    Title:              Date Opened: 9/18/96     Assigned To:

34017          Contacts frozen     First Rev.               MDR Line



(1) Team Leader:    Interim   Problem Reported By:     RME #:

Mark Bryant         Final     Customer                 34017 & 34406



                              Date 9/18/96   Responsibility M. Bryant



(2) Describe Problem:



Customer:                ABB Combustion Engineering Nuclear Operations

                         P.O. Box 500 M/S 9426-1936

                         Windsor, CT 06095-0500

                         Attn: Jack Buckholz



Product:                 MDR-170-1

Date(s):                 9412 (red) (S/N 514)

Mfg. Plant:              Marion

Customer References:     CE Order# 407112-01, CE Reference# 011-95823-

                              0040

Siemens References:      RA# 9643077, Ack# 13745, PO# 407112

                         RME 32276 (S/N 513), RME 34406 (S/N 511 & 512)

Reason For Customer

Return:                  Contacts frozen

Problem Identification/

Verification:            Verified by Princeton Failure Analysis Lab,

rotor remains bound in energized position without coil power.



(2) Evaluation                  Date: 9/23/96   Responsibility: M. Bryant

Black substance rolled up around the tip of the rotor shaft on the bottom

bell.  Substance is causing rotor to bind which prevents proper contact

operation.



(3) Containment & Interim

Corrective Action(s):            Date: 9/18/96  Responsibility: M. Bryant

Contacted Sales to have Return Authorization issued for the remaining two

MDR-170-1 units built for the original release in 1994.  S/N 511 & 512.

(RA 9643079 / RME 34406))

Due to the isolated nature MDR units presently in service or on the

shelf.



Siemens Electromechanical Components, Inc.



Potter & Brumfield       200 South Richland Creek Drive       Tel 812

                                                              386-1000

Products Division        Princeton, IN 47671-0001             Fax 812

                                                              386-2430



13E163 06/04/96



                                                                   Page 2

RME # 34017



(4.) Define & Verify Root

Cause(Codes):                  Date: 12/18/96   Responsibility: M. Bryant



Materials & Processes Lab has determined the cause for bound rotor was

contamination of the bearing grease with glass particles and other debris

(S/N 514).  The contaminants reacted with the grease to form a black

substance which would not allow the rotor to turn freely.  The major

components of the contamination were silicon from glass fibers found in

the contact ring insulator plates and flakes of coil epoxy.  These

components are inherent to parts handling in the assembly area M&P Lab

found similar contamination in S/N 511 & 512 although these units were

still operable.  S/N 513 returned in October '95, should also be

considered to fall under this response (ref RA 9541066 / RME 32276)



Exactly how such a quantity of contaminants could accumulate in these 4

relays is not known.  Due to line improvements, layout changes and

personnel turnover since 1994 it is difficult to identify a specific root

cause for this isolated problem.



M&P lab identification of the contaminants shows no indication this

problem is related to the coil varnish outgassing problem which caused

similar binding problems in the past (units built prior to date code

9024)



Coils were gaged on the MDR line and found to be well within tolerance

and in no way oversize.



Document changes required

                              Yes  No        N/A       Date Changed

Change Flow Diagram                X

Change Process FMEA                X

Change Design FMEA                 X

Change Control Plan                X

Change Attribute Procedure         X

Routings                           X

Drawings                           X

Others                             X



13E163 06/04/96



RME # 34017                                                       Page #3



(5.) Establish Corrective

Action Plan                     Date: 1/8/97   Responsibility:  M. Bryant



While the source of the contamination to the motor assembly could not be

definitely determined, the following improvements have occurred since the

discrepant units were manufactured in 1994

- Enclosed booth built to isolate MDR final assembly stations from

general production area to reduce contamination and noise levels

- Added additional process step to fabrication of insulator plates Parts

are tumbled following blanking operation in order to remove loose

particles and fibers

- Initiation of Continuous Improvement teams and successful QS9000 effort

have resulted in formalized housekeeping procedures which mandate daily

clean up by the operators.  These have contributed greatly to improving

general production area cleanliness

- Continuous improvement teams have also worked to significantly reduce

the inventory level of parts and sub assemblies stacked on the production

line and in the Stockroom The reduced inventory levels result in more of

a JIT system which limits the opportunity for contamination to the

subassemblies



A review of the present MDR production for further potential sources of

contamination showed the following problem areas:

- The assembly operators maintained a small cup of grease at each

assembly station and used a toothpick to apply a dab of grease from the

cup to the bearing surfaces.  The grease cups were uncovered and would

collect contamination on the surface of the grease supply.

These cups were replaced with plastic syringes which seal off the grease

supply from any contaminants (eff 9640, 10/1/96)

- No instructions existed to prevent the operators from beginning

assembly of a unit and then later setting it aside to work on a different

unit, The possibility existed for a partially assembled unit to collect

contaminants on a greased bearing surface.

Operators have been instructed to ensure any partially assembled units

are properly covered when it becomes necessary to put them aside or they

are to complete the unit to the point of sealing the motor assembly

Grease is to be removed from any questionable units and fresh grease

applied.  Instructions reflecting these requirements are in process to be

added to MDR Engineering Specifications (eff. 9640)



Existing assembly instructions require each motor assembly be blown out

with de-ionized air in order to remove any contamination prior to capping

the motor assembly with the too end bell.  It is felt that the present

MDR assembly methods, process controls and housekeeping measures are

adequate to preclude further occurrence of this problem.



(6.) Implement & Verify

Corrective Action(s):            Date: 1/8/97  Responsibility: M.  Bryant

- 5 piece MDR sample taken from present MDR production and examined for

contamination, No contaminated motor assemblies were found.

- 6 MDR units successfully completed mechanical life testing to 500,000

operations @ 5 ops./min. on 12/22/95 This is submitted as an indication

of the reliability of recent production.



Date Implemented             Date Verified:                  Verified By:

10/1/96                          1/8/97                         M. Bryant



Document changes required

                              Yes  No        N/A       Date Changed



Change Flow Diagram                X

Change Process FMEA                X

Change Design FMEA                 X

Change Control Plan                X

Change Attribute Procedure         X

Routings                           X

Drawings                           X

Others                             X



13E163 06/04/96



RME # 34017                                                       Page #4



(7) Actions to Prevent Recurrence: Date: 1/8/97 Responsibility M. Bryant

Actions taken are applicable to all MDR part numbers



(8.) Congratulate/Team Members: Date: 1/8/97 Responsibility  M. Bryant



Distribution

Mike Carnahan

Gale Maxwell

Michael Goldhacker

Don Deel

Dick Market

Ed Wagner

Karen Greenwall

Jack Buckholtz ABB (FAX)



Document changes required

                              Yes  No        N/A       Date Changed



Change Flow Diagram                X

Change Process FMEA                X

Change Design FMEA                 X

Change Control Plan                X

Change Attribute Procedure         X

Routings                           X

Drawings                           X

Others                             X



13E163 06/04/96



SIEMENS



                 Part List of Potential Affected Devices

                     With Date Codes of 9317 to 9532



MDR-141-1                MDR-6054       MDR-7033-SCE-0

MDR-141-1-SCE-2          MDR-6059       MDR-7034

MDR-141-2                MDR-6050       MDR-7034-SCE-0

MDR-142-1                MDR-6054       MDR-7033-SCE-1

MDR-167-1                MDR-6069       MDR-7036

MDR-170-1                MDR-45074      MDR-7045

MDR-170-1-SCE-2          MDR-6100       MDR-7048

MDR-170-2                MDR-6101       MDR-7052

MDR-172-1                MDR-66-4       MDR-7056

MDR-173-1                MDR-7020       MDR-7059

MDR-6007                 MDR-7025       MDR-7067

MDR-6019                 MDR-7029       MDR-7068

MDR-6041                 MDR-7032       MDR-7069

MDR-60150                MDR-7032-SCE-0

                         MDR-7033



                                                             Attachment 2



Siemens Electromechanical Components, Inc.



200 South Richland, Creek Drive    Tel 812 386 1000

Princeton, IN 47671-0001           Fax 812 386 2430



SIEMENS                        Siemens Electromechanical Components, Inc.



Fax



To:                                     From:



Company:                                Department:



Department:                             Fax: (502) 965-1212



Fax:                                    Telephone:

Telephone:                              Date:             Pgs. to follow:



Message



Potter & Brumfield Products Division

726 Chapel Hill Road

Marion, KY 42064

502.965.3193



*** END OF DOCUMENT ***



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