ML15054A473

Columbia Generating Station- Pre-Submittal Public Meeting with Energy Northwest to Discuss Upcoming Relief Request Regarding Reactor Water Cleanup System (TAC No. MF5679)

ML15054A473
Person / Time
Site:	Columbia
Issue date:	02/23/2015
From:	Reddemann M E Energy Northwest
To:	George A E Plant Licensing Branch IV
George A E
References
TAC MF5679
Download: ML15054A473 (26)

Text

Relief Request for Reactor Water Cleanup (RWCU) System Components Energy Northwest February 24, 2015 AGENDAIntroductionBackgroundRelief RequestTechnical EvaluationConclusion 2

INTRODUCTIONComponents in the non-safety related portions of the Reactor Water Cleanup System which do not conform to ASME design requirements (due to historical reclassification activities) perform with an acceptable level of safety and quality for extended in-plant operation 3

BACKGROUND: RWCU System DescriptionContinuously purifies reactor water during all modes of reactor operation Takes suction from the inlet of each reactor recirculation pump and from the reactor pressure vessel bottom head and returns processed water to reactor pressure vessel, main condenser, or radwasteEquipment located in the reactor building includes main system pumps and regenerative and non-regenerative heat exchangersEquipment located in the radwaste building includes filter-demineralizers and supporting equipment 4

BACKGROUND: History of RWCU system classificationNon-safety related portion of system originally classified Quality Group C as defined in Regulatory Guide (RG)

1.26 Rev. 3ASME Section III, Class 3 (ASME III/3)1995: Demineralizer portion of the system difficult to operate due to excessive boundary valve leakageSought new valve design to improve system reliabilityASME valves un-reliable and difficult to maintain due to parts availabilityHigh dose impact for repeat maintenance on ASME valvesEN identified a highly reliable valve, but the valve was not available with ASME certification 5

BACKGROUND: History (continued)1995: EN initiated reclassification of non-safety related portion of RWCU system in accordance with Regulatory Guide (RG) 1.26 Rev. 3 by taking advantage of note 6:"Components in influent lines may be classified as Group D provided they are capable of being isolated from the reactor coolant pressure boundary by an additional valve which has high leaktight integrity."Reclassified portions of system to B31.1 (Group D) with the new code break set one valve beyond the credited pressure boundary 1996: NRC Inspection Report 50-397/96-11 identifies weaknesses with 50.59 safety evaluation (SE) supporting reclassification but concludes SE is adequate 6

BACKGROUND: History (continued)1998: NRC challenged the conclusion that the requirements of RG 1.26 note 6 were met1998: In response, the 50.59 safety evaluation was rewritten and concluded that NRC approval was not

required2013: NRC issued a violation for failure to obtain NRC approval of the portions of the RWCU system that were reclassified (IR 50-397/13-03 -ML13206A131) 7 BACKGROUND: RWCU System Unaffected ComponentsSafety related ASME valves, piping, hangers and instruments were not included in the reclassificationNon-safety related heat exchangers were not included in the reclassificationNon-safety related ASME piping and hangers were not repaired or replaced 8

BACKGROUND: RWCU System Non-Conforming ComponentsRemoved strainer on the demineralizer filter inlet (replaced with ASME pipe and elbows) without ASME Section XI work planReplaced the main RWCU pumps' ASME sealless water-cooled motor assemblies with non-ASME

assembliesReplaced 9 ASME globe valve pressure boundary parts with ANSI partsReplaced 29 ASME ball valves with ANSI B31.1 plug valves9 BACKGROUND: Corrective ActionsDocumented violation in a condition report Identified population of non-conforming componentsIssued Functionality Determination for continued operationCompleted Apparent Cause Evaluation and identified corrective actions 10 BACKGROUND: Corrective Actions (continued)Design documents changed to restore original Quality Group C classificationCompleted nondestructive examination (NDE) of ANSI welds with no recordable indications observedInitiated project to identify and purchase suitable replacement ASME componentsPurchased spare ASME pump motor assemblyReplaced two ANSI valves with ASME III/3 valves 11 RELIEF REQUEST: Applicable Code and DurationColumbia ASME Section XI Code is the 2001 Edition through the 2003 AddendaRelief requested from requirements of IWA-4221(b)(1):Requires that an item used for repair/replacement activities meet the Construction Code to which the original item was constructed.Relief is requested pursuant to 10 CFR 50.55a(z)(i) -the proposed alternative would provide an acceptable level of

quality and safetyDuration of request is for remaining period of the third inservice inspection interval ending December 12, 2015, and

the fourth interval ending December 12, 2025 12 RELIEF REQUEST: Proposed ActionsFor ASME valves maintained with ANSI parts:Repair will be performed in accordance with ASME Section XI using ASME Section III construction code requirementsFor ASME valves replaced with ANSI valves:Repair will be performed in accordance with ASME Section XI using ANSI construction code requirements until the valves are

replacedFuture valve replacements will be performed in accordance with ASME Section XI using ASME Section III Construction Code

valves and requirements 13 RELIEF REQUEST: Proposed Actions (continued)For ASME Pumps with Non-ASME Motor Assemblies:Repair will be performed in accordance with ASME Section XI using ASME Section III Construction Code requirementsReplacements will be performed in accordance with ASME Section XI using ASME Section III Construction Code pump motor assemblies and requirements 14 RELIEF REQUEST: Proposed Actions (continued)Demineralizer influent strainer (replaced with pipe and elbows):Accept as isASME Section III material was installedASME Section IX welding installed itQC visual examinations of welds were performedNDE surface examinations were performed (no recordable indications) 15 TECHNICAL EVALUATION: SafetyReactor coolant pressure boundary isolation not affectedAutomatic system isolation function not affectedPipe break detection instrumentation not affectedNo new postulated break locations introducedPostulated high energy line breaks described in FSAR chapter 3.6None of the piping in the reactor building where pipe breaks are postulated was replaced or repaired; i.e., it is still ASME III/3Existing FSAR safety analysis for postulated pipe ruptures involving RWCU system outside of containment

are not impacted 16 TECHNICAL EVALUATION: QualityANSI B31.1 materials and components were subject to the Owner's quality control programReceiving of materials and components, inspection, and assignment of unique identification to parts and materials used for repairs and replacementsInstallation of components used welding procedures qualified to ASME Section IX, welding filler material control, and final QC inspection of the welds made in conformance to the

design requirementsParts installed can be traced back to material requests and specific catalogue identification number associated with the design requirements and ASME or ASTM standard 17 TECHNICAL EVALUATION:

ValvesFor the ASME III/3 and ANSI B31.1 valves, the standard utilized is B16.5 (B16.34 for current Code years) The two Codes provide the same dimensional guidance for critical configurations (e.g. valve ends)The two Codes provide the same requirements for socket welds and butt weldsWelding is performed using ASME Section IX requirements for both ANSI B31.1 and ASME III/3 18 TECHNICAL EVALUATION: WeldsThe ASME Section III Code of Record for the RWCU system is the 1971 Edition with Winter 1973 AddendaReplaced components used either butt welds or small bore socket weldsFor small bore socket welds, a visual inspection is requiredANSI butt welds greater than 2 inches that required NDE surface exams received NDE in 2014 using magnetic particle (MT) examination and were satisfactory 19 TECHNICAL EVALUATION: PumpsThe currently installed sealless water-cooled motor assemblies were designed to ASME III/3, but not constructed to ASME III/3Replacement motor casing assemblies fabricated from ASME material and the fabrication me thods used were controlled by applicable welding procedures for the materials of construction.

The NDE methods employed meet the intent of the ASME Code and the final hydrostatic test was conducted at the required

pressure with an extended hold time using an ASME Section III pressure test procedureThe currently installed pump cases are original OEM ASME III/3 parts, were not replaced, and remain in place 20 TECHNICAL EVALUATION: Operating ExperienceThe replacement plug valves installed per ANSI B31.1 have performed very wellMinor packing leaks and limit switch adjustments have been performedANSI valves operated the first 10 years without any seat leakage issuesOf the 31 ANSI valves installed in 1996 and 1997, two valves developed seat leakage in 2008, three in 2012 and two in 2014 21 TECHNICAL EVALUATION: Operating ExperiencePump motor assemblies were replaced due to motor stator failures and not pressure boundary failuresNo pressure boundary failures of ANSI components have been experienced 22 CONCLUSIONRelief is requested from the ASME Section XI code requirement of IWA-4221(b)(1) based upon 10 CFR

50.55a(z)(i)A total of 41 RWCU system components currently do not meet requirements of ASME Section III, Class 3Technical evaluation shows excellent operating history for ANSI componentsAffected components have demonstrated performance with an acceptable level of safety and quality and are suitable for extended in-plant operation 23 CLEANUP RECIRCPUMP 1AV-34FIGURE 1. REACTOR WATER CLEANUP SYSTEM 830651.2LT FEB 2015Color RWCU MOMOMOFIR609MOV-100MOV-101V-102MOREACTORVESSELMOV-106TO REACTOR RECIRCPUMP ATO REACTOR RECIRCPUMP BISOLATION SIGNALRMSMOINBDISOL.VALVEA. C.V-1FE35RMSMOOUTBDISOL.VALVED. C.V-4FT36V-5AV-5BPRIMARYCONTAINMENT V-769V-768V-12AV-13AV-13BV-12BCLEANUP RECIRCPUMP 1BFE40V-104MOV-42MOV-40V-105MOV-31RO1FCV-33BLOWDOWNFLOWCONTROLVALVE V-32AOAOV-231AV-231BFCV-266AFCV-266BRTRTV-206BV-232BMOV-44AOV-206AV-232ARX CLOSED COOLING WATER EDR2A2BNON-REGENERATIVE HEAT EXCHANGER 1A1B1CREGENERATIVE HEAT EXCHANGERS V-767V-766V-765EDRTO MAINCONDENSER DRAIN TO WASTE COLLECTOR OR SURGE TANK (RADWASTE)

K602RETURN TO FEEDWATER FTFILTER DEMIN

' A 'FILTER DEMIN

' B '41EDRPUMP SUCTION SUBCOOLING LINE MOMOMOMOFE11FT15V-35(DELTA FLOW ISOLATION)

FS15RWCU-V-4ISOLATION SIGNALFT16FS16RWCU-V-1ISOLATION SIGNALAOAOKEY:PUMP MOTOR/MOTOR CASE REPLACED NON-ASMEREPLACED WITH ANSI VALVEINTERNAL COMPONENTS REPLACED WITH NON-ASME SECTION III NDE PERFORMED EXTENT OF SYSTEM RECLASSIFICATION ASME III CLASS 3 (NON-SAFETY)ASME III CLASS 2 (SAFETY RELATED) - NOT PART OF RECLASSIFICATIONASME III CLASS 1 (SAFETY RELATED)

ASME III CLASS 1(SAFETY RELATED)RADWASTE BUILDING 1150 PSIG 120° F 1200 PSIG 520° F AO 234FIGURE 2. RWCU RADWASTE BUILDING(REPRESENTATIVE OF ONE DEMINERALIZER) 950155.27Color Feb 2015RWCUFGAO207 230AIR FILTERFEAO213FROM NRHX (INFLUENT)

CLEANUP PHAS ESEPARATOR BACKWASH AIR233(BACKWASH OUT) 208206AOAOAOAO232242243(BACKWASH)241FEFTAO231266FCV(BACKWASH VENT) dPISdPIS245244(EFFLUENT)

(TRAP BACKWASH)

FROMCONDEN-SATESTRAINER 92 REMOVEDAO229212TUBE SHEET VENT239AOAO214238211AO210AO235HOLD PUMP P34"4"3"3"2"2"1"1"1/2"1/2"FROM PRECOATTO PRECOATTO PRECOATTANKFROMOTHER DEMIN TOOTHERDEMINTO RHX248247246KEY:REPLACED WITH ANSI VALVEINTERNAL COMPONENTS REPLACED WITH NON

-ASME SECTION III NDE PERFORMED SUCTION INLETDIFFUSERTHERMOWELLSTATOR WINDINGSSTATOR LAMINATIONSPUMP CASEDISCHARGEIMPELLER PURGE CONNECTION PUMP END BEARINGL. P.

COOLING WATER MOTOR CAVITY HEAT EXCHANGER MOUNTING BRACKETS H. P.

COOLING WATERFILTERMOTOR COVERFILLER AND DRAIN CONNECTION840183.02LT AUGUST 1995 RWCUROTOR MOTOR CASE COVER END BEARING THRUST BEARING ASSEMBLYFIGURE 2A. RWCU PUMP/MOTOR CAVITY HEAT EXCHANGER