ML15187A172

Interim Part 21 Report - Potential Test Induced Defect in 0867F Main Steam Safety Relief Valves

ML15187A172
Person / Time
Site:	Hatch, Hope Creek, Pilgrim, FitzPatrick
Issue date:	06/30/2015
From:	DeBonis J Curtiss-Wright Flow Control Corp
To:	Document Control Desk, NRC Region 1
References
NID#15428
Download: ML15187A172 (9)

Text

0613012015Padc, 1063/05U.S. Nuclear Reuulatorv Commission Overations Center Event Renort Pam.pPart 21 (PAR) Event # 50900Rep Org: CURTISS WRIGHT FLOW CONTROL CO. Notification Date / Time: 03/17/2015 09:59 (EDT)Supplier: CURTISS WRIGHT FLOW CONTROL CO. Event Date I Time: 03/17/2015 (EDT)Last Modification: 06/30/2015Region: 1 Docket #:City: EAST FARMINGDALE Agreement State: YesCounty: License #:State: NYNRC Notified by: JOHN DeBONIS Notifications: GLENN DENTEL R1DOHQ Ops Officer: STEVE SANDIN BINOY DESAI R2DOEmergency Class: NON EMERGENCY PART 21/50.55 REACTORS EMAIL10 CFR Section:21.21(a)(2) INTERIM EVAL OF DEVIATIONINTERIM PART 21 REPORT -POTENTIAL TEST INDUCED DEFECT IN A 0867F MAIN STEAM SAFETYRELIEF VALVESThe following report was received from Curtiss -Wright via email:"This letter provides interim notification of a potential test induced defect in a 0867F Series Main Steam SafetyRelief Valves (MS-SRVs) manufactured and supplied by Target Rock (TR). The information required for thisnotification is provided below:"(i) Name and address of the individual or individuals informing the Commission.William BrunetDirector of Quality AssuranceJames WhiteGeneral ManagerTarget Rock, Business Unit of Curtiss-Wright Flow Control Corporation1966E Broadhollow RoadEast Farmingdale, NY 11735"(ii) Identification of the basic component supplied for such facility or such activity within the United States whichmay fail to comply or contains a potential defect.Target Rock 0867F Series of Main Steam-Safety Relief Valves Manufactured by Target Rock. This is a 3-stagepiloted valve consisting of a main valve (the 'Main') with an actuator mounted to it (the 'Topworks'). The 0867F isthe latest generation of the 67F line of MS-SRVs, including the original 3-Stage and 2-Stage designs, and this 06/30/2015 U.S. Nuclear Regulatory Commission Operations Center Event Report Page 2product line has over 40 years of plant operational experience. Only the 0867F is under investigation. This is dueto the differences between the 0867F design and the other designs."(iii) Identification of the firm supplying the basic component which fails to comply or contains a defect.Target Rock, Business Unit of Curtiss-Wright Flow Control Corporation1966E Broadhollow RoadEast Farmingdale, NY 11735"(iv) Nature of the defect or failure to comply and the safety hazard which is created or could be created by suchdefect or failure to comply.As we understand it, the Pilgrim Station recently manually opened the Target Rock Main Steam Safety ReliefValves (MS-SRVs) as part of cooling down the reactor following a loss of offsite power. One of the four installedMS-SRVs may not have fully opened. As-found steam testing of the affected MS-SRV did not duplicate this failure;the valve opened on demand. However, the valve did not re-close as expected. Internal inspections founddamaged parts in the main stage subassembly that could potentially affect the ability of the MS-SRV to operate asdesigned.We are investigating potential root causes for this damage. However, we are still unable to determine if a specificdefect exists. GE SIL-196, Supplement 17 determined Main Spring relaxation was caused by 'extreme dynamicsencountered during limited flow testing .Valve dynamics under full flow conditions (i.e. discharge not gagged) aremuch less severe than those under limited flow conditions.' These extreme dynamics, under limited flow testconditions, are the focus of our investigation. Specific areas of investigation include;a) Testing of materials to verify they are consistent with our material specifications,b) evaluation of differences between the 0867F and earlier designs, andc) evaluation of the differences between different limited flow test loop configurations and test procedures"(v) The date on which the information of such defect or failure to comply was obtained.The Pilgrim event occurred on January 27, 2015. As-found testing occurred on February 2, 2015."(vi) In the case of a basic component which contains a defect or fails to comply, the number and location of thesecomponents in use at, supplied for, being supplied for, or may be supplied for, manufactured, or beingmanufactured for one or more facilities or activities subject to the regulations in this part.While we have yet to determine if a specific defect exists, the following plants were supplied 0867F MS-SRVs:-Pilgrim (Model 09J-001) Quantity Shipped = 8-Fitzpatrick (Model 09H-001) Quantity Shipped = 4, Quantity on order= 8-Hatch 1 and 2 (Model 09G-001) Quantity Shipped= 24, Quantity on order= 12The following plants will be supplied 0867F MS-SRVs:-Hope Creek (Models 14J-001, 14J-002) Quantity on order = 7"(vii) The corrective action which has been, is being, or will be taken; the name of the individual or organizationresponsible for the action; and the length of time that has been or will be taken to complete the action.The root cause of the potential test induced defect has not yet been confirmed as of the date of this report.Therefore, no specific corrective actions have been initiated. Target Rock Problem Report 080 will document thecorrective actions when they are determined and complete the 10 CFR Part 21 evaluation of the potential testinduced defect. This determination will be based on further mechanical and material evaluations. TR anticipatescompleting these evaluations within 45 days; however, in the event the evaluations are not completed, TR willforward another interim report within 45 days.

.06/30/2015 U.S. Nuclear Regulatory Commission Operations Center Event Report Page 3"(viii) Any advice-related to the defect or failure to comply about the facility, activity, or basic component that hasbeen, is being, or will be given to purchasers or licensees.We are working with all three (4) sites to identify appropriate precautions."(ix) In the case of an early site permit, the entities to whom an early site permit was transferred.Not applicable."Should you have any questions regarding this matter, please contact Michael Cinque, Director of ProgramManagement at (631 ) 293-3800."* *

• UPDATE FROM JOHN DeBONIS (VIA EMAIL) TO HOWlE CROUCH AT 1355 EDT ON 5/1/15 * * *Curtiss-Wright provided an update to state that their root cause analysis is still in progress and they anticipatecompletion within 60 days.Notified NRR Part 21 Group (via email), R1 DO (Gray), and R2DO (Ehrhardt).* *

• UPDATE FROM JOHN DeBONIS (VIA EMAIL) TO STEVEN VITTO AT 1256 EDT ON 6/30/15 ***Curtiss-Wright provided an update to state their root cause analysis findings and corrective actions. Correctiveactions are estimated to be completed within 12 months."The following plants were supplied 0867F MS-SRVs:Pilgrim (Model 09J-001) Quantity Shipped = 8FitzPatrick (Model 09H-001) Quantity Shipped = 4, Quantity on order= 8Hatch 1 and 2 (Model 09G-001) Quantity Shipped = 24, Quantity on order= 12"The following plants will be supplied 0867F MS-SRVs:Hope Creek (Models 14J-001, 14J-002) Quantity on order = 7"Valves Currently Installed"Target Rock recommends valves currently installed be inspected to ensure the main piston shoulder has contactwith the main disc stem shoulder. These inspections should be scheduled based on plant-specific indications ofthe potential for fretting. These inspections can be performed by removing the base assembly from the main bodyand physically measuring for shoulder-to-shoulder contact."Should you have any questions regarding this matter, please contact Michael Cinque, Director of ProgramManagement at (631 ) 293-3800."Notified NRR Part 21 Group (via email), R1 DO (Dimitriadis), and R2DO (Suggs).

CURTISS -WRIGHTValve Group -Target RockIndustrial Division1966E Broadhollow RoadE Farmingdale, NY 11735, USAT: +1.631.293.3800 I F: +1.631.293.4949www.cw-industrial.comNID#15428June 30, 2015Attn: Document Control DeskU.S. Nuclear Regulatory CommissionWashington, D.C. 20555-001

Subject:

10 CFR Part 21 ReportNotification of a Defect, Potential for Test Induced Damage0867F Series Main Steam Safety Relief Valves

Reference:

(1) Target Rock Letter NID#15155 to U.S. NRC Document Control Desk,"Interim Report -Notification of a Potential Test Induced Defect", datedMarch 12, 2015(2) Target Rock Letter NID#15308 to U.S. NRC Document Control Desk,"Interim Report -Updated Notification of a Potential for Test InducedDamage", dated May 1, 2015

Dear Sir or Madam:

Target Rock, a business unit of Curtiss-Wright Flow Control Corporation (TR), submitted theReference (1) and (2) Interim Reports regarding a potential test induced defect in the 0867FSeries of Main Steam Safety Relief Valves (MS-SRV). This letter provides an update on ourinvestigation and notification of a test induced defect that could impact the valves' ability tofunction as designed.(i) Name and address of the individual or individuals informing the Commission.William BrunetDirector of Quality AssuranceMichael CinqueGeneral ManagerTarget Rock, Business Unit of Curtiss-Wright Flow Control Corporation1966E Broadhollow RoadEast Farmingdale, NY 11735(ii) Identification of the basic component supplied for such facility or such activity within theUnited States which may fail to comply or contains a potential defect.Target Rock 0867F Series Main Steam-Safety Relief Valves Manufactured by Target Rock.This is a 3-stage piloted valve consisting of a main valve (the "Main") with an actuator mountedto it (the "Topworks"). The 0867F is the latest generation of the 67F line of MS-SRVs, including;the original 3-Stage (73/7467F), the vertical discharge 3-Stage (9867F), and the 2-Stage(7567F) designs. This product line has over 40 years of plant operational experience. TRreviewed all designs and determined this notification only applies to the 0867F valves due todifferences between the 0867F design and the other designs.

NID 15428Page 2(iii) Identification of the firm supplying. the basic component which fails to comply or contains adefect.Target Rock, Business Unit of Curtiss-Wright Flow Control Corporation1966E Broadhollow RoadEast Farmingdale, NY 11735(iv) Nature of the defect or failure to comply and the safety hazard which is created or could becreated by such defect or failure to comply.BackgroundAs we understand it, in January 2015, the Pilgrim Station manually opened Target Rock 0867FMain Steam Safety Relief Valves (MS-SRVs) during reactor cool down, following a loss of offsitepower. One of the four installed 0867F MS-SRVs may not have fully opened (SIN 9). As-foundsteam testing of the affected MS-SRV did not duplicate this failure; the valve opened ondemand. However, the valve did not re-close as expected.Post (As-found) test internal inspections revealed: (a) the main piston was free to "wobble" onthe stem; (b) deep fretting damage to the main guide ID; (c) the locking tab was deformed to thepoint it could no longer perform its intended function; (d) shortened free height of the mainspring; and (e) significant deformation of the mating surfaces of both the stem and the piston.Root CauseIn its root cause evaluation, TR considered all potential causes starting with the adequacy ofdesign in accordance with the specification requirements for the application into which thesevalves are installed, including, but not limited to manufacturing and sub-contract processes,compliance of installed components with design requirements (materials, material properties,dimensions, test facility set-up and processes, test results etc.). Through these efforts TRconcluded the 0867F valve is appropriately designed and manufactured in accordance with thespecification requirements.Although TR's review and analyses concluded the 0867F valves are designed appropriately,these efforts did yield a root cause for the noted valve condition as follows:TR determined the root cause of main guide fretting due to piston ring wear resulted fromexcessive impact load during limited flow testing which relieves the torque applied to thepiston/stem interface (de-torqueing) leading to the creation of a significant clearance betweenthe piston and the main disc (de-shouldering). This loss of shoulder-to-shoulder contact allowsrelative motion between the main piston and main disc. If the excessive impact load alsodamages the jam nut or tab washer and shortens the main spring well below the GE SIL-196requirement, plant vibratory loads can allow the piston to rotate circumferentially and rockrelative to the stem shoulder further increasing the clearance between it and the stem. Thisaction is time dependent -increasing the amount of time the piston is exposed to theseconditions will increase the propensity for fretting wear.The chain of events that lead to fretting of the main guide is given below. Fretting of the mainguide was not required to be assumed or considered in the valve design.1. Limited flow testing imparts impact loads that damage internals on the 0867F design. GESIL-196, Supplement 17 determined Main Spring relaxation was caused by "extremedynamics encountered during limited flow testing .... Valve dynamics under full flow NID 15428Page 3conditions (i.e. discharge not gagged) are much less severe than those under limitedflow conditions."2. When the impact load is much greater than the local yield strength, the preload on thejoint is not only removed but clearance is established between the disc and pistonshoulders. Additional cycles increase the clearance, and damage to disc undercut, discthreads and piston shoulder. This is significantly different than the minor local yieldingthat occurs during normal limited flow cycling for all other 67F designs. These designsallow very little plastic deformation of the disc undercut and no plastic deformation of thepiston shoulder and threads. Under this scenario, shoulder to shoulder contact (gaps upto 0.002 inch) is maintained and relief of preload is acceptable.3. If the impact load is excessive, it may deliver significant plastic deformation of the matingsurfaces on the piston and/or disc. The relative motion between the piston and disc willincrease. The impact load is sufficient to permanently deform threads on the piston and/or disc. There was evidence of rolled threads on the Pilgrim S/N 4 and 9 main piston andmain disc, indicating an excessive force was applied.4. Excessive impact load may also cause the tab washer to bend around the jam nut axiallyso it is no longer staked in the piston slot. With preload removed and the tab washer nolonger in the piston slot, in-plant flow induced vibration acts on the piston to increase theclearance between the piston and stem shoulder.5. The main spring free length is also decreased due to the velocity attained duringopening (reference GE SIL 196, Supplement 17). If the spring free length is shortenednear the installed height of main disc and piston assembly, the spring will not provideadequate resistive load to keep the piston from vibrating.6. In some cases, gaps greater than 0.002 inches may allow the piston to rock on the stemshoulder, wearing grooves into the main guide (fretting). The induced vibration load isplant specific.7. The fretting wear of the main guide liner also wears the piston rings. The fretting wearcan progress to a point where an additional clearance exists between the piston ringsand the main guide. This clearance can grow in size such that the effective area of theclearance is on the same order as the effective area of the 2nd stage seat. If thishappens, a differential pressure cannot be established across the main piston to providethe opening force. As inlet pressure decreases, this effect will be exacerbated.8. Given the noted discrepancies, the valve may develop fretting driven by plant-specificconditions (for example vibration/pressure loads) that increase main stage friction duringstroking that was not required to be assumed or considered in the valve design.9. With fretting present, the valve may not operate under all design conditions.Applicability to Other 67F DesignsThis root cause is limited to the 0867F design provided GE SIL 646 and SIL 196, Supplement17 modifications have been implemented. There are a number of differences between the0867F and earlier designs which incrementally reduce opening velocity, and therefore impactloads, on the earlier designs, during limited flow testing.a) 7567F and 9867F models have a much smaller flow area between the valve inlet andunderside of the piston and a large bypass orifice around the piston. These reduce maindisc/piston speed.b) Model 73/7467F has three (3) specific differences from the 0867F that decreases theimpact force, including: (a) smaller main throat sizes, (b) shorter stroke, and (c) a filterinstalled around the main .guide which acts to decrease the pressure on the underside ofthe piston during valve opening.

NID 15428Page 4(v) The date on which the information of such defect or failure to comply was obtained.The Pilgrim event occurred on January 27, 2015. As-found testing occurred on February 2,2015.(vi) In the case of a basic component which contains a defect or fails to comply, the numberand location of these components in use at, supplied for, being supplied for, or may be suppliedfor, manufactured, or being manufactured for one or more facilities or activities subject to theregulations in this part.The following plants were supplied 0867F MS-SRVs:* Pilgrim (Model 09J-001) Quantity Shipped = 8* FitzPatrick (Model 09H-001) Quantity Shipped = 4, Quantity on order = 8o Hatch 1 and 2 (Model 09G-001) Quantity Shipped = 24, Quantity on order = 12The following plants will be supplied 0867F MS-SRVs:Hope Creek (Models 14J-001, 14J-002) Quantity on order = 7(vii) The corrective action which has been, is being, or will be taken; the name of the individualor organization responsible for the action; and the length of time that has been or will be takento complete the action.Target Rock Actions estimated to be completed within 12 MonthsTarget Rock Problem Report 080 has documented the root cause and contributing factors. TR ispursuing an enhanced 0867F design, which will: (a) eliminate actions noted below for valvescurrently or not yet installed; (b) continue to meet in-service specification requirements; and (c)be better able to mitigate the extreme loads encountered in limited flow testing. As part of thiseffort, TR will focus, but not limit its efforts on an the main valve subassembly which willpotentially include the main body, main disc, main piston, jam nut and locking tab to reduce theimpact velocity of the main disc/piston assembly to be on the same order of magnitude as theother valve designs (73/7467F, 7567F and 9867F). The target impact velocity will initially be 2.6m/s (102 in/s) or slower.By reducing the impact velocity, the main spring loss of free height will be minimized and the tabwasher will remain in place. We also -expect modified valves will continue to exhibit de-torqueing, consistent with the as-found condition of the other valve designs (73/7467F, 7567Fand 9867F), but there will be no de-shouldering which is the required predecessor for fretting.Limited flow and full flow testing will verify the change does not violate any operationalspecification requirements. Inspections will verify the redesign has not de-shouldered. TR willuse a threshold shoulder-to-shoulder gap of 0.002 or less post-test to substantiate the adequacyof the design based on a practical maximum gap requirement that can be measured and stillverify the integrity of the joint. The main spring free height should remain above the GE SIL 196,Supplement 17 recommendation of 6.32 inches for at least 30 limited flow cycles.The current time frame to complete the redesign and qualification testing is expected to bewithin 12 months. The final configuration will be based on our continuing evaluations.

NID 15428Page 5(viii) Any advice related to the defect or failure to comply about the facility, activity, or basiccomponent that has been, is being, or will be given to purchasers or licensees.Valves Currently InstalledTarget Rock recommends valves currently installed be inspected to ensure the main pistonshoulder has contact with the main disc stem shoulder. These inspections should be scheduledbased on plant-specific indications of the potential for fretting. These inspections can beperformed by removing the, base assembly from the main body and physically measuring forshoulder-to-shoulder contact. At this time, TR has limited"0867F information with regard to theas-found condition of the piston/main disc shoulder. Of thirteen (13) total main valves inspected,nine (9) were Pilgrim main valves, four (4) were Hatch main valves and zero (0) were FitzPatrickmain valves. Four (4) Pilgrim valves had a measurable gap (greater than 0.002 inches). None ofthe Hatch valves had a measureable gap. Because of the difference in as-found gapmeasurement, there may be differences between plants that have a significant difference in thepotential extent of condition for installed valves. The inspection schedule should be determinedby the end user based on the potential for de-shouldering and subsequent in-plant fretting.To facilitate these inspections TR is developing a test fixture to differentiate between shortsprings and increased friction in an installed main assembly. The fixture will allow the user todetermine the condition of the spring load as a function of valve lift. This fixture may also be anoption for As-left testing of the main valve assembly.Valves Not Yet InstalledFor valves that will be certified (As-left test), TR recommends minimizing limited flow cycles andperforming additional inspections after the test. These inspections require the base assembly tobe removed from the main body after as-left testing to inspect the threaded main disc/mainpiston connection. If the joint is satisfactory, the valve can be reassembled and retested formain seat leakage and base/body leakage. If the joint is unsatisfactory, the joint can beinspected and re-torqued, which requires removal of the internal subassembly from the mainbody. If the main spring free length is reduced below the GE SIL 196 requirement, the mainspring shall be replaced. The valve can be reassembled and retested on steam for main seatleakage and base/body leakage, without the need for cycling the valve again. Provided thevalves have satisfactorily passed the post-lifting inspection described above after limited-flowtesting, these valves are acceptable for installation in the plant.(ix) In the case of an early site permit, the entities to whom an early site permit wastransferred.Not applicable.

NID 15428Page 6Should you have any questions regarding this matter, please contact Michael Cinque, GeneralManager at (631) 293-3800Very Truly Yours,Michae aCinqueGeneral ManagerTarget Rock, Business Unit of Curtiss-Wright Flow Control Corporationcc: James WhiteWilliam BrunetSteve PaulyAlex DiMeoJohn DeBonisEd Bradshaw