ML18243A511
| ML18243A511 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/28/2018 |
| From: | Franchuk T Curtiss-Wright Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18243A511 (8) | |
Text
CURTISS.- Nuclear Division 4600 East.Tech Drive WRIGHT T:
Cincinh'ati, OH 45245
.513.528.7900 l F: 513:528.9292 .
www.cwnucle~r.com U.S .. Nuclear Regulatory Qlmmission Attn: Document Control D~k
- Washington,, DC 20555;.oooi Date: 8/28/18 * *
Subject:
Senasys Selector Switch P/N 910CMC-5240X, Part 21 notification To Whom it may concern, This letter serves as an official report in accordance with 10CFR Part 21.21 pertaining to post-Installation test failure ofSenasys Selector Switch P/N 910CMC,.5240X.
Curtii;s-Wright was nQtifi.ed by Exelo11 Calvert Cliffs Pl.811.t that a Sen~sy's selector swit~h PIN 91 QCMC-5.240X (previously provided by Curtiss.~Wright und¢r* Exelon purchase order 00630804), had failed a post-installation test. Calvert Cliffs sent the suspect switch to Exelon Powerlabs where the failure was found to have been caused by an assembly screw that was 1/8 inch too long, allowing it to cut into the .coil of the switch, causing ah electrical short.
Corre:spondence between Exelon and the manufacturer determined that an inventory error had occurr~d, as noted below by the :tn811ufactur~:
The root cause was determined in our inventory - it seems the 'found' screws had been dumped into an open box of screws for the CMC units and they were not correct. This created the issue you are seeing. This was reported as a handful of screws .. After they first reported problem, our inventory was quarantined and all the screws were inspected.
The time frame has been determined to be the end of 2017 (seems to be, November and December).
According to our r¢cords, cmly one custonier and on~ plant received these defoctive switches. Exelon Generap.on's Calvert Cli£fs received 5 switches on Exelon PO number 00630804 Rev. 2. Exelon Calvert Cliffs has been notified of this issue.
Curtiss Wrighfs dedication plan will be revised to include a note to ensure no selector switches, for this part number are manufactured with the November and December 2017 date codes.
The Exelon Power]abs Failure Analysis Report is attached.
Page2 If you have any questions pertaining to this informatio11, please contact Timothy
. Franchuk, Director of Quality Assurance, at 513--201-2176 Sincerely:
cc: Regional Administrator, USNRC, Region II
= Exelon Generationg Allll!lf 7
Exelon Powerlabs To: Victor Sacket, Calvert Cliffs Station From: Skip Booz, (610) 380-2440 Skip.Booz@ExelonPowerLabs.com Project: . CCN-00&52
Subject:
Failure Analysis of a Selector Switch Manufadurer: Senasys, Inc.
Model: 910CMC-5240X Stock Code/Cat ID: 0001774009 AR/CR/WO: 04130071/ MO C93664356 Quantity Received: 1 Date: 25 June 2018.
- I . STATION DESCRIPTION Switch was new from stock, installed in 2018 RFO (April 2018) and found failed during subsequent testing. Control circuit found grounded isolated to inside hand switch. Appears that switch mounting screw penetrated one of the internal lighting transformers. Marked on switch with X".
CONCLlJSIONS PowerLabs confirmed that one of the four mounting fastener screws penetrated the associated internal lighting transformer, causing it to short to the grounded panel board. The cause was a wrong length screw being supplied with the switch. Three of the mounting fastener screws were 1-3/8" long, but the forth screw was 1-1/2" long. The extra 1/8" allowed it to puncture the transformer when the fastener screw was tightened as part of switch installation. All (4) switch lamps had previously been illumination tested satisfactorily at PowerLabs as part of Parts Quality Initiative (PQI) testing, substantiating the theoiy that the damage occurred as part of switch panel mounting.
.____________ C_OMME
_ _NT_S_AN_D_RE_C_O_MME _ _ND_A_T_I_O_N_S_ _ _ _ _ _ _ _.l I
I The switch was safety related and the supplier/dedicator (Curtiss-Wright) sp.ould be notified I regarding Part 21 implications.
Any remaining swi_tches should be checked to confirm none of the mounting fastener screws are the wrong length. There were (5) switches PQI tested in January 2018, so there is likely at least (3) in stock. Based on the nature of this failure installed switches would not be impacted by this issue since the problem would be apparent during post-,installation testing.
The Exelon PowerLabs Quality System meets 10CFR50 Appendix B, NQA-1 (1994), ANSI N45.2, ANSJ/NCSL Z540.3-2006, ISO 9001 :2008, ISO 17025:2005, and 10CFR21/IOCFR50.55 (e).
175 N. Caln Road Coatesville, PA Page 1 of 6
I COMMENTS AND RECOMMENDATIONS (Continued);:_ *..
Senasys was aware of the issue and will replace the switch at no cost. Refer to the Discovery section of this report for details.
The PowerLabs PQI testing templates for this switch and similar models wiUbe revis¢ to include inspection of the mounting fastener screws to confirm proper length'.
REQUIREMENTS J Determine if this was a manufacturing defect, compare other positions, determine if there is a possibility of this being a Part 21 issue.
l TEST PLAN
- 1. Document Nameplate Information
- 2. Document As-Received Condjtion
- 3. Perform Electrical Testing
- 4. Perform Disassembly and Analysis
- 5. Document Discovery Items STATEMENT.OF QUALITY -. -I Testing was perfomied with standard equipment that have accuracies traceable to nationally recognized standards, or to physical constants, by qualified personnel, and in accordance with the Exelon PowerLabs Quality Assurance Program.
Technician(s): Skip Booz, (610) 380-2440, Skip.Booz@ExelonPowerLabs.com Prepared by: Skip Booz 6/25/18 ANSI Level m / Sr Engineer Date Reviewed by: Joe Mulcahv 6/25/18 ANSI Level ID/ Sr. Engineer Date Approved by: - - - - - - - - - - - ' - - - - - - - - - - - - - - - - - - - - - - - -
ANSI Level ill / Sr. Engineer Date Project review and approval are electronically authenticated in the Exelon PowerLabs project record.
cc:
Exelon PowerLabs, LLC :... TECH SERVICES Project Number: CCN-00852 175 N. Caln Road Coatesville, PA Page2 of6
OBSERVATIONS AND DATA I. Document Nameplate Data Photos 1, 2 & 3: Switch Nameplate Manufacturer: Senasys Type: CMC Series Multi-Light Oiltight Selector Switch Model: 9IOBFAOI 1 910-Greyknob B - Position 1, 2, 3
.E - Orientation 1 A - Maintained 01-5 Terminals, 120V Transformers, No.755 Lamps l - Turn Cam Orientation Part No.: 9IOCMC-5240X Date Code: 17 .11.02 {likely Nov. 2, 2017)
Dedication: Switch was dedicated by Curtiss-Wright under Exelon PO 00630804
- 2. As-Received Condition The selector switch was in good condition. Photo 4: Selector Switch There were a few minor scratches on the body and cover lens. and no evidence of physical damage.
The switch had a solidly constructed feel. There was no exterior evidence of physical, electrical or thermal damage. It emitted no unusual aroma.
The mounting gasket was intact and the (4) mounting fasteners were loose on the screws.
When manipulated, there was a slight rattle in the bulb area of the switch.
The cover plate and lens were secured tight to the switch body.
There was a PowerLabs test sticker on the switch body (CCN-74260-01).
Exelon PowerLabs, LLC - TECH SERVICES Project Number: CCN-00852 17 5 N. Caln Road Coatesville, PA Page 3 of6
- 2. As-Received Condition (Continued)
There was a blue 'X' on the side of the body near Photo 5: Station Marking on Switch one of the mounting fasteners.
All (5) tenninal screws were intact but loose.
The contact block was missing from the switch end. The cam appeared to be in good condition..
The switch snapped smoothly between all three positions. The knob and cam wiggled slightly at each position (less than 1/16").
- 3. Electrical Testing The following static electrical testing was performed on the switch:
- Insulation resistance was checked at 500 VDC from each mounting fastener to all (5) terminals. All readings were very good (> 100 GO).
- Resistance was checked from each numbered terminal (I to 4) to the common terminal (C).
The resistances of terminals 1-C, 2-C and 4-C were 1176, 1222 and 1139 n, respectively.
Terminals 3-C were found to be open circuited. This reading indicated an issue with the associated lamp transformer, as identified by the station.
- The (4) lamps were removed and resistance checked. The readings ranged between 4.3 and 5.2 n.
- 4. Disassembly and Analysis Photo 6: Switch Disassembly The selector switch was disassembled to investigate the issue. The photo shows one of the mounting fasteners removed from the switch and one still installed. The fasteners swing out when the switch is installed in the panel cutout and draws it in snug to the panel when tightened.
There are (4) mounting fasteners, one on each side.
Exelon PowerLabs, LLC - TECH SERVICES Project Number: CCN-00852 17 5 N. Caln Road Coatesville, PA Page 4 of 6
- 4. Disassembly and Analysis (Continued)
Photos 7 and 8: Switch Lamp Transformers When the switch was disassembled far enough to expose the lamp transformers, the suspected damage was evident. The mounting fastener screw appeared to have punctured the transformer windings. There are (4) holes in the molded plastic cover (blue arrows) that help keep the fastener screws in place, but the screws should no be able to reach the transformer.
Photos 9 and 10: Mounting Fastener Screws The mounting fastener screws were inspected and one was found to be l /8" longer than the rest When the switch was installed in the panel and tightened, the longer screw punctured the lamp transformer causing a short to ground. During CCN-74260 PQI testing at PowerLabs, a lamp illumination test was performed satisfactorily on this switch. This confirmed the switch was not damaged when shipped from Curtiss-Wright, but the incorrect screw caused the damage during installation.
Exelon PowerLabs, LLC - TECH SERVICES Project Number: CCN-00852 175 N. Caln Road Coatesville, PA Page 5 of 6
- 5. Material Analysis (if necessary)
No material analysis was warranted or performed.
- 6. Discovery Senasys was contacted and the representative was familiar with the issue. It occurs rarely and Senasys policy is to replace the defective switch at no cost, except for return shipping of the switch.
The representative provided the following RMA and returning shipping address:
RMA Number - 15672 Return Mailing Address - 704 Bartlett Ave., Altoona, WI 54720 End of Report Exelon PowerLabs, LLC - TECH SERVICES Project Number: CCN-00852 17 5 N. Caln Road Coatesville, PA Page 6 of6