ML15099A042

Notification of Part 21 Report - Potentially Defective Pressure & Temperature Switches

ML15099A042
Person / Time
Site:	Davis Besse, Browns Ferry, Harris, Watts Bar, Sequoyah, River Bend, Vermont Yankee
Issue date:	04/02/2015
From:	Dirks M SOR
To:	Office of Nuclear Reactor Regulation
References
50299
Download: ML15099A042 (3)

Text

0)4/02/2015SPoop I040/5U.S. Nuclear Rem ltorv Co isskion Onerations C'enter Event Rennrt Pope,Part 21 (PAR) Event# 50299Rep Org: SOR INC. Notification Date / Time: 07/23/2014 15:15 (EDT)Supplier: SOR INC. Event Date I Time: 07/16/2014 (CDT)Last Modification: 04/02/2015Region: 4 Docket #:City: LENEXA Agreement State: YesCounty: License #:State: KSNRC Notified by: MELANIE DIRKS Notifications: MEL GRAY R1DOHQ Ops Officer: STEVE SANDIN RANDY MUSSER R2DOEmergency Class: NON EMERGENCY STEVE ORTH R3DO10 CFR Section: GEOFFREY MILLER R4DO21.21(d)(3)(i) DEFECTS AND NONCOMPLIANCE NRR PART 21 EMAILPART 21 REPORT -POTENTIALLY DEFECTIVE PRESSURE & TEMPERATURE SWITCHESThe following information was originally received in NRC Region IV on July 16, 2014 via email. Relevant portionsof the submittal are provided below without graphs, tables or pictures."SOR is a supplier of basic components to the nuclear power industry. The components of concern for thisnotification are SOR nuclear qualified Pressure and Temperature switches with TA housings manufactured from2004 through 2009."The defect being reported is a potential out of tolerance condition concerning the machined sealing surface for anenvironmental seal on the SOR nuclear TA housing. Other switches with a similar defect have the potential to notmeet their intended safety function."Summary: SOR Inc. began a 10CFR21 evaluation on 6/4/14 upon receipt of three SOR pressure switches,model number 5TA-B45-U8-C1A-JJTTNQ (SN's 041100627, 041100628, and 041100629). These were returnedfrom Entergy Nuclear Vermont Yankee (VY) due to inspections which questioned the suitability of the sealingsurfaces on the face of the housings where the cover 0-ring seals."The product evaluation was concluded on 6/24/14 and it was determined that this issue is a reportable defect asdefined by 1 OCFR Part 21. If the switch housing has an inadequate machined sealing surface, the potential existsfor steam permeation into the switch housing during accident conditions. This could result in an increase in setpoint as well as allow moisture into the housing potentially causing electrical consequences such as currentleakage or a short. It is anticipated that the above noted condition represents a small percentage of the totalnumber of housings from this batch of castings. Also, the potential risk is thought to be small due to a secondredundant seal on the cover. This condition is being reported as a conservative measure.

0410212015U.S. Nuclear Regulatory Commission Operations Center Event ReportPage 2"Evaluation: There are 2 (redundant) environmental seals on the cover of the nuclear TA housing. One O-ringseals on the undercut of the cover threads (151 0-ring). This seal is not in question and is not part of thisevaluation. The other O-ring seals between the face of the enclosure and the O-ring groove on the cover (042 0-ring). This is the seal that is the subject of this evaluation."Redundant O-ring seals are used on the SOR 'TA' cover to minimize steam permeation into the housing duringLOCA or HELB conditions. The consequences of permeation are that it can result in an increase in the set pointand also allow moisture into the housing which could have electrical consequences. The returned switches have asuspect sealing surface on the face of the housing where one of the two O-rings (the 042 O-ring) is intended toseal. For the purposes of this Part 21 evaluation, consideration needs to be given to whether this suspect sealingsurface could result in increased permeation into the switch enclosure."Switches #041100627 and 041100628 both have an area on the face of the housing where the casting did nothave sufficient material for cleanup when the housing was machined. This area was characterized by use of theSOR CMM and measuring the area where the O-ring is expected to seal."Switch #041100629 was different from #041100627 and 041100628 in that it had one small indentation in thesealing surface which was immeasurable but does not meet surface finish requirements."The TA housings on the returned switches are clearly out of tolerance. It is SOR's position that the environmentalseals on any switch with a similar defect has the potential to not meet its' intended safety function..."Evaluation of Previous Shipments: SOR has validated shipments for a quantity of 56 pressure and temperatureswitches with the subject TA housing."Potentially affected customers/utilities include: TVA/Watts Bar, TVA/Browns Ferry, TVA/Sequoyah, EntergyNuclearNermont Yankee, Entergy Operations/River Bend, Southern California Edison, Third QinshanNuclear/QSNPP-3-A (TQNPC), Fairbanks Morse Engine, STP Nuclear Operating Co., Hydro Quebec /Gentilly II,Progress Energy/Shearon Harris, Control Components Inc./Korea Hydro Nuclear Shin-Kori & Wolsong, ControlComponents Inc./KHPN Shin Kori 3 & 4, Korea Hydro & Nuclear/KHPN Yonggwang NPP #5, KonanEngineering/Yonggwang Nuclear, and First Energy/Davis-Besse Nuclear. (Total Potentially Affected = 56."Root Cause: The returned TA housing castings did not meet print and therefore did not allow enough material forcleanup of the machined sealing surface."Permanent Corrective Action: SOR internal documentation is being changed to require 100% inspection of theraw casting height. Also, the 1/8 [inch] minimum finish dimension is being added to the housing machiningdrawings."Action by Nuclear Power Plant: SOR recommends that the application for each switch noted in the above tablebe reviewed to determine if it is being used in a LOCA or HELB application. If so, SOR recommends an inspectionto visually check for an adequate sealing surface of the housing .This inspection is also recommended forswitches that have not yet been installed. The minimum required sealing surface is 1/8 [inch] (0.125 [inch]). Afterinspection, all units should have the 042 and 151 O-rings replaced if the units do not exhibit the deviation."SOR will send replacement 0-rings at no charge upon request. If units are found that do not meet the acceptancecriteria, they will be replaced free of charge by SOR. Contact SOR Director of Customer Service, Greg Barber forthe replacements:"Greg Barber"913-956-3059"gbarber@sorinc.com"* *

• UPDATE FROM MELANIE DIRKS TO VINCE KLCO ON 4/2/15 AT 1421 EDT ***The following information was excerpted from a facsimile:

04/02/2015 U.S. Nuclear Regulatory Commission Operations Center Event Report Page 3Korea Hydro Nuclear power plants were added to include Shin-Kori 1 & 2; Shin Wolsong 1 & 2.Notified the Part 21 Reactors Group via email.