ML101170050
| ML101170050 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 04/14/2010 |
| From: | Florida Power & Light Co |
| To: | Division Reactor Projects II |
| Shared Package | |
| ML101170029 | List: |
| References | |
| Download: ML101170050 (35) | |
Text
Regulatory/Enforcement ConferenceFlorida Power & Light CompanyTurkey Point Unit 3 Boraflex DegradationApril 14, 2010 2List of AttendeesGene St. Pierre, Vice President, Fleet Support Michael Kiley, Vice President, Turkey PointLarry Nicholson, Director of LicensingRobert Tomonto, Licensing Manager, Turkey PointCarl OFarrill, Nuclear Fuel Engineering ManagerJohn Laffrey, Senior Licensing Engineer, CorporateWilliam Blair, Senior Attorney 3AgendaIntroductionOpening RemarksBackgroundBoraflex Management ProgramDiscussion of Apparent ViolationsClosing Remarks 4Purpose of PresentationPresent background on Turkey Point Unit 3 Spent Fuel Pool and Boraflex Management ProgramPresent FPL conclusions regarding the apparent violations associated with Boraflex degradation specifically identified in the Turkey Point Unit 3 Spent Fuel Pool 5Opening RemarksTurkey Point 3 Spent Fuel Pool (SFP) has always been maintained in a safe configuration, with sufficient margin to criticality The most reactive available fuel assembly could be safely placed in the most degraded cell, without credit for either soluble boron or interim compensatory measures, and Keff would still remain <1.0FPL's goal is to eliminate need for Boraflex in Turkey Point 3 SFP; removing any reliance on monitoring and interim compensatory measures Despite continuous efforts, numerous design and vendor production quality issues contributed to significant delays in implementation FPL is responsible for not implementing the Boraflex Remedy in a timely fashion FPL is now making progress to complete the Boraflex Remedy by Fall 2010 6BackgroundBoraflex degradation managed as operable/degraded non
-conforming condition in accordance with GL 91
-18/RIS 2005-20 guidanceInterim measures implemented to compensate for degradation prior to reaching design basis analysis assumption of 0.006 gms-B 10/cm 2Action taken at 0.0075 gm
-B 10/cm 2Final resolution includes use of Metamic insertsFabrication to specified tolerances found to be extremely difficultVendor production rate now acceptable: 80 inserts installed to dateFabrication issues delayed implementation of approved License Amendment 234 7Background (contd) FPL December 31, 2009 submittal outlined interim actions NRC Confirmatory Action Letter (CAL)issued on February 19, 2010 to confirm acceptability of FPL interim actionsFinal Boraflex resolution for Unit 3 expected by Fall 2010We missed several opportunities over the years of this project to keep the NRC fully aware of the implementation issues and the condition of Unit 3s SFP. This lack of communication and information sharing on our part, we believe, is a significant contributor to the need for todays discussion TimelineTurkey Point Nuclear Plant 6-26-1996GL 96-04 requests Boraflex Monitoring Program response 10-18-1996FPL response to GL 96-04states Blackness testing and Silica Monitoring 11-30-1999FPL LAR describesBlackness testing and Silica monitoring 3-8-2000FPL RAI response commits to substitute Blackness with upgraded test 7-5-2000FPL letter states Boraflex Surveillance will be tracked as commitment 7-19-2000NRC SE for Amendment 206/200acknowledges FPL commitment to perform 5/2001 Boraflex surveillance 5-16-2001FPL letter changes test frequency commitmentfrom 5 to 3 years and describes test results, RACKLIFE, and admin controlsJune 2004 Second BADGER test report identifies R19 panel <.006 gm B10/cm 2 01-27-2006 Boraflex Remedy LAR June 2007Third BADGER test report 5-15-2000FPL letter states intention to measure gaps, shrinkage and areal density 4-1-2001 FPL implements GL 91-18 admin controlsJan 2001 First BADGER test reportMay 2010Next BADGER test using RACKLIFE predictions
-Unit 4Turkey Point Nuclear PlantUnit 3 SFP Boraflex Management Program 07-17-2007 BoraflexAmendments 234/229 02-19-2010 NRC CAL 12-31-2009FPL submittal of interim actions 9BackgroundThe Turkey Point Unit 3 SFP has two regionsRegion I -designed to store higher reactivity fuel including fresh fuelRegion II
-designed to store lower reactivity burned fuelBoth regions contain storage racks (placed in service in 1985) that use Boraflex neutron absorber to control reactivityAccumulated gamma dose and long term exposure to the wet pool environment cause the Boraflex panels to degradeThe Region II racks have been subject to greater gamma dose due to the storage of burned fuel and have, therefore, experienced a greater amount of degradation 10Background (contd)Boraflex Licensing Basis Overview10 CFR 50.68 establishes Keff requirements for SFP storage racksTechnical Specification (TS) 5.5.1.1 specifies design requirements for the SFP racks, as detailed in UFSAR, to comply with 10 CFR 50.68 Keff requirements Associated Region II licensing basis analysis conservatively assumes a uniform minimal areal density to bound the effect of any actual Boraflex dissolutionEvery panel in every cell assumed to be at the same dissolved B-10 areal density of 0.006 gms
-B10/cm2 Background (contd)Metamic Insert 12Boraflex Management ProgramPurpose:Manage Boraflex degradation to ensure the requirement for Keff <1.0 unborated is maintained in the SFPObjective: To ensure implementation of compensatory measures before degradation exceeds licensing basis assumption of 0.006 gms
-B 10/cm 2Establishes administrative limit with an action threshold at 0.0075 gms
-B 10/cm 2 13Boraflex Management Program (contd)The program is based on monitoring and predicting the condition of the Boraflex panels using advanced techniquesMeasuring and trending silica released to the SFP from the degrading panelsEPRI-RACKLIFE predictive code benchmarked to SFP silica and periodically updated to account for gamma dose from fuel repositioning on individual panelsEPRI-BADGER (Boron
-10 Areal Density Gage for Evaluating Racks) in-situ areal density testing of a sample of panels in the SFPThese three elements are endorsed by NUREG 1801, Rev.
1, Generic Aging Lessons Learnedto manage the effects of aging on BoraflexRACKLIFE has been used at 25 SFPs and BADGER testing at 14 SFPs throughout the industry (FPL implements full program; others implement partial program) 14Boraflex Management Program (contd)Turkey Point Unit 3 RACKLIFE model update and analysis is performed at least once per operating cycle (every 18 months) or when significant fuel repositioning occursRACKLIFE model has been conservatively benchmarked to the Turkey Point Unit 3 SFP bulk silica concentration trendRACKLIFE provides a predicted condition of each panel; used to determine when to take compensatory action for a storage cellRACKLIFE used to determine the sample of panels to be measured covering a full range of service historiesBADGER used to validate RACKLIFE modeling 15Boraflex Management Program (contd)BADGER testing at Turkey Point Unit 3 conducted in 2001, 2004, and 20072001 results
-used to determine administrative controls needed to meet TS 5.5.1.12004 results
-one panel below design bases analysis assumption of 0.006 gms
-B 10/cm 22007 results average panel at approximately 0.012 gms-B 10/cm 2 areal density 16Boraflex Management Program (contd)BADGER testing has validated RACKLIFE predictions to be conservative on a storage cell basisThe impact on Keff from dissolution of a single panel is affected by the areal density of the other panels in a storage cell and, therefore, the condition of all panels in a cell must be considered RACKLIFE conservatively predicts the cumulative areal density of the four panels in a storage cell by 10.4% when compared to BADGER test results, with a 95% probability and 95% confidence (95/95 lower confidence limit)The conservative RACKLIFE model, combined with the conservative action threshold of 0.0075 gms
-B 10/cm 2 , provides significant margin to ensure action is taken to assure Keff <1.0 unborated is maintainedRACKLIFE predictions are conservative on a cell basis 17Boraflex Management Program (contd)Since 2001, conservative actions taken to manage Boraflex degradation to ensure unborated Keff <1.0 include:Established checkerboardstorage rack module Module configured to not require credit for Boraflex Used to store recently discharged fuel assemblies Helps to limit pool
-wide Boraflex degradationMitigated storage cells that have anypanel with areal density below administrative action threshold of 0.0075 gms
-B 10/cm 2No longer credit Boraflex in the cellRemove cell from service, orInsert RCCAs to compensate for Boraflex lossThese actions did not require any increase in soluble boron to maintain Keff <1.0Boraflex degradation effectively mitigated without crediting soluble boron 18Boraflex Management Program (contd) Unit 3 SFP Current Condition258 of 1,404 Boraflex storage cells have been placed under administrative control as part of the Boraflex Management ProgramTo date, one Region II storage cell panel (R19
-east) measured (2004) with an areal density below 0.006 gms
-B 10/cm 2(i.e., .0056) while other panels in the cell measured well above 0.006
gms-B 10/cm 2The cell was already under administrative control since 2001, aspart of the checkerboardstorage rack moduleAs of today, RACKLIFE indicates no additional panels have an areal density below the licensing basis assumption of 0.006
gms-B 10/cm 2 19Boraflex Management Program (contd)Region 2Region 2Region 2Region 2Region 1Symbol KeyRegion 1Region 1Cell under admin controlR19Unit 3 Spent Fuel Pool Current Boraflex Degradation 20Boraflex Management Program (contd)Safety Significance of Boraflex DegradationNo safety significance associated with the condition of the Unit 3 SFPTo date, only one panel in one cell has been determined to be below the licensing basis areal density input assumption, versus many that are above the assumed minimum areal densityThe most reactive available fuel assembly could be safely placed in the most degraded cell, without credit for either soluble boron or interim compensatory measures, and Keff would still remain <1.0 21Boraflex Management Program (contd)Safety Significance of Boraflex DegradationBoraflex Management Program has been effective in preventing any safety significance associated with Boraflex degradationDesigned to take actions prior to exceeding licensing assumptionSignificant margin has been preserved by administratively controlled actions 22Boraflex Management Program (contd)Safety Significance of Boraflex DegradationDefense in depth with two effective, independent and diverse means of SFP reactivity control have been utilizedSFP racks with administrative control ensured Keff <1.0 unborated, and Soluble boron to ensure Keff 0.95Keff was always maintained within limits 23 (1)Failure to Comply with TS 5.5.1.1.a and 10 CFR 50.68(b)(4)Apparent violation:Failure to comply with TS 5.5.1.1.a and 10 CFR 50.68(b)(4) requirements to assure that the effective neutron multiplication factor (Keff) would be maintained <1.0 for all cases in the Unit 3 spent fuel pool when flooded with unborated waterDiscussion:FPL agrees with the apparent violation of TS 5.5.1.1.aFPL considered compliance achieved by confirmation that the Boraflex surrounding each cell was sufficient to ensure acceptable Keff resultsFPL did not apply NRC interpretation that compliance is dependent on each individual panel, without consideration for the condition of the remaining panels in a cellViolation occurred in 2004 when the east panel in cell R19 was determined to be less than the required areal densityAs a result, FPL did not submit a 10 CFR 50.73 report as a condition prohibited by TS 24 (1)Failure to Comply with TS 5.5.1.1.a and 10 CFR 50.68(b)(4) (contd)Discussion:FPL respectfully disagrees that an apparent violation of 10 CFR 50.68(b)(4) occurred10 CFR 50.68(b)(4) establishes the Keff requirements for the SFP storage racks under certain specified conditionsKeff of the SFP storage racks was always maintained within the requirements under all the conditions specified in 10 CFR 50.68Keff was always maintained within limits 25 (1)Failure to Comply with TS 5.5.1.1.a and 10 CFR 50.68(b)(4) (contd)Safety Significance:There was no adverse impact on nuclear safetyKeff <1.0 unborated was maintained at all timesOnly one panel in a single cell has been determined to date to fall below the areal density assumed in the licensing basis analysisThe typical panel remains well above the areal density limit assumed in the licensing basis analysisThere is inherent conservatism within the Boraflex Management Program to offset the uncertainties of panel measurementNo credit has been taken for soluble boron, thus preserving an independent, diverse and effective means of reactivity control 26 (2)Failure to Implement Effective Corrective Action Relative to SFP cells L38 and F19Apparent violation:Failure to implement effective corrective actions for two specific cells that had degradation determined to be greater than that assumed in the criticality analysisDiscussion:FPL respectfully disagrees with the apparent violation as statedSFP cells L38 and F19 were determined to have exceeded the FPL action threshold but not the density value assumed in the criticality analysis 27(2) Failure to Implement Effective Corrective Action Relative to SFP cells L38 and F19 (contd)Circumstances for Cell L38:BADGER testing in 2007 identified that the east panel of cell L38 was at 0.0071 gms
-B 10/cm 2At that time, RACKLIFE was predicting this specific L38 panel to be above the action thresholdThe Boraflex Management Program relied upon RACKLIFE results to take actions and did not explicitly require action based solely on BADGER results The issue was entered into the corrective action program, after NRC identification, and storage cell L38 was placed under administrative control on November 13, 2009 28(2) Failure to Implement Effective Corrective Action Relative to SFP cells L38 and F19 (contd)Circumstances for Cell L38:Corrective actions:Program has been revised to also take action, if needed, based on BADGER resultsThere are no other panels with BADGER results below the action limit that are not already under administrative controlSafety SignificanceThis event is of no safety significanceAnalysis of the actual fuel stored in and around L38 demonstrate s a Keff <1.0 unboratedAnalysis assuming that the most reactive fuel available is store d in and around L38 also demonstrates a Keff <1.0 unborated 29 (2)Failure to Implement Effective Corrective Action Relative to SFP cells L38 and F19 (contd)Circumstances for Cell F19:In January 2009, RACKLIFE projected the west and south panels of F19 to reach the action threshold in June and July of 2009On September 1, 2009, during a routine RACKLIFE update, FPL discovered that cell F19 had not been placed under administrative controlCondition report generated, RCCA inserted into F19Areal density of west and south panels determined to be at or above 0.0072 gms
-B 10/cm 2when placed under administrative controlCause determined to be human errorNo safety significance 30Apparent violation:Failure to make notification to the NRC in accordance with 10 CFR 50.73Discussion:FPL agrees with the apparent violationReport was not submitted as a direct result of not interpreting TS appropriatelyFPL should have reported the condition of cell R19, discovered in 2004, as a condition prohibited by TS pursuant to 10 CFR 50.73(a)(2)(i)(B)Time of discovery established on March 9, 2010, report being developed (3)Failure to Report Condition Prohibited by TS 31 (4)Failure to Update UFSARApparent violation:Failure to update the UFSAR to reflect the interim monitoring program and associated compensatory measures being used since 2001Discussion:FPL agrees that a violation of 10 CFR 50.71(e) occurred in that the compensatory measures taken between 2001 and present should have been described in the UFSARUFSAR was updated in 2002 to provide general description of Boraflex Surveillance ProgramBoraflex monitoring aspect has been captured and tracked as a formal commitmentCompensatory measures have been considered as short
-term interim measures under GL91
-18/RIS2005
-20Given the duration, the UFSAR should have been updated to include the Boraflex Program details 32 (4)Failure to update UFSAR (contd)Actions taken:FPL updated UFSAR Section 9.5 on March 1, 2010 to describe the Boraflex Management Program, including the monitoring and interim compensatory actionsSignificance: FPL has continued to perform Boraflex surveillance testing as committed in License Amendment 206/200FPL has managed the compensatory measures consistent with the guidance found in GL 91
-18 as revised in RIS 2005
-20 33 (5)Failure to Perform Adequate 50.59 EvaluationApparent ViolationFailure to maintain a written evaluation which provided the bases for the determination that the change to the design of the spent fuel pool storage racks, without the use of Metamic inserts, did not require a license amendmentDiscussion:FPL respectfully disagrees that a violation of 10 CFR 50.59 occurredThe inability to implement the license amendment that credited Metamic inserts does not constitute a proposed change, test or experiment within the context of 10 CFR 50.59 34 (5)Failure to Perform Adequate 50.59 Evaluation (contd)Discussion:Existing licensing basis analysis was reviewed & approved via Amendment 206/200 dated 7/19/2000RIS 2005-20 provides appropriate regulatory framework to evaluate effects of interim compensatory measuresMetamicinserts are currently being installed under 10 CFR 50.59 with no credit to offset Boraflex degradationSituation very unique, no clear policy or precedent relative to the inability to implement an approved amendment 35Closing Remarks