ML13192A033

Watts Bar Nuclear Plant Unit 1 - Reply to a Notice of Violation; EA-13-018

ML13192A033
Person / Time
Site:	Watts Bar
Issue date:	07/03/2013
From:	Shea J W Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-018
Download: ML13192A033 (12)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402July 3, 201310 CFR 2.201ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant Unit 1Facility Operating License No. NPF-90NRC Docket No. 50-390

Subject:

Reply to a Notice of Violation; EA-13-018

References:

1. Letter from NRC to TVA, "Watts Bar Nuclear Plant -NRC Inspection Report05000390/2012009; Preliminary Yellow Findings, Preliminary WhiteFindings and Apparent Violations,"

dated March 12, 20132. TVA Nuclear Power Group Hydrology Regulatory Conference slides(ADAMS Accession No. ML13115A020)

3. Letter from NRC to TVA, "Watts Bar Unit 1 Nuclear Plant -FinalSignificance Determination of Yellow Finding, White Finding and Notices ofViolations; Assessment Follow-up Letter; Inspection Report No.05000390/2013009,"

dated June 4, 2013In accordance with the NRC letter dated March 12, 2013 (Reference 1), Tennessee ValleyAuthority (TVA) requested a Regulatory Conference to discuss the apparent violations documented in Reference

1. The Regulatory Conference was conducted on April 22, 2013,during which TVA made a presentation on the issues (Reference 2). Subsequently, theNRC issued Notice of Violation EA-1 3-018 on June 4, 2013 (Reference 3). In accordance with the NRC's June 4, 2013 letter, TVA is required to respond to the Notice of Violation within 30 days of the date of the letter.TVA's response to this Notice of Violation is provided in the enclosure in accordance with10 Code of Federal Regulations (CFR) 2.201, "Notice of Violation."

Printed on recycled paper U.S. Nuclear Regulatory Commission Page 2July 3, 2013There are no new regulatory commitments contained in this response.

Should you have anyquestions concerning this submittal, please contact D. K. Guinn, Nuclear Site Licensing

Manager, at (423) 365-1589.

Resp ully,J. .eaVi e Nuclear Licensing

Enclosure:

Reply to a Notice of Violation; EA-1 3-018cc (Enclosures):

NRC Regional Administrator

-Region IINRC Senior Resident Inspector

-Watts Bar Unit 1 Nuclear Plant ENCLOSURE Tennessee Valley Authority Watts Bar Nuclear Plant Unit IReply to a Notice of Violation; EA-13-018 Reply to a Notice of Violation; EA-13-018 Restatement of Violation ATechnical Specification 5.7.1, Procedures, requires in part that written procedures shall beestablished, implemented, and maintained covering the activities recommended inRegulatory Guide 1.33 [Quality Assurance Program Requirements (Operations)],

Revision 2,Appendix A, February 1978.Regulatory Guide 1.33, Revision 2, Appendix A, includes "Abnormal Conditions" as a typicalsafety-related activity that should be covered by written procedures.

Abnormal Operating Instruction (AOI) 7.1, "Maximum Probable Flood," Revision 16,provides detailed instructions for implementing required site flood mitigation strategies necessary to cope with design basis flooding events.Contrary to the above, prior to September 30, 2009, the licensee failed to establish and/ormaintain an adequate Abnormal Operating Instruction procedure to implement its floodmitigation strategy.

Specifically, AOI 7.1 was inadequate to mitigate the effects of aProbable Maximum Flood (PMF) event, in that earthen dams located upstream of the facilitycould potentially

overtop, causing a subsequent breach. Failure of the earthen dams duringa PMF event would have resulted in onsite flooding and subsequent submergence of criticalequipment, such as the Emergency Diesel Generators, resulting in an ineffective floodmitigation strategy for these PMF events.Background It was determined on July 28, 2009, that an upstream dam (Fort Loudoun) would overtopand fail during a design basis PMF. Subsequent to this date, it was discovered thatCherokee,

Tellico, and Watts Bar dams had a similar design vulnerability that would alsoresult in a higher flood elevation at the WBN site.TVA performed an analysis and determined that the overtopping and failure of the specified earthen embankments would have resulted in an increase in the PMF level at Watts BarNuclear Plant (WBN) and would have the potential to affect systems required for safeshutdown.

The overtopping of the dams represented an unanalyzed condition.

Subsequent analysis determined that the calculated increase in flood level at WBN from a PMF event inwhich the specified earthen embankments were overtopped and failed rendered existingflood mode procedures ineffective.

In July and August 2009, TVA implemented interim compensatory measures to mitigateimpacts of the potential dam overtopping issues. TVA modified River Operations procedures to notify WBN if 5 inches or greater average rainfall over 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> occurs overthe watershed above the Fort Loudoun and Tellico dams. At the same rainfall threshold, TVA procedures required the mobilization of the necessary heavy equipment to remove theFort Loudoun Marina Saddle dam to preserve the integrity of Fort Loudoun Dam. In thissame time period, TVA commenced installation of the Hercules Engineering Solutions Consortium (HESCO) barriers on the Fort Loudoun,

Tellico, Watts Bar, and Cherokee dams.These modifications were implemented to effectively raise dam embankments 3 feet to 8El of 9 Reply to a Notice of Violation; EA-13-018 feet, which prevent flood overtopping and potential impacts to the dam earthenembankments and possible

failure, and protect critical WBN facility operations.

By December 30, 2009, the HESCO barriers installation was completed.

Post-HESCO PMFcalculations were issued for WBN to bring WBN into compliance with the licensedconditions.

Reason for the Violation The reasons for this violation are as follows.* The Simulated Open Channel Hydraulics (SOCH) model had design input errors dueto overconfidence in the adequacy of the model and in the calculation process.

Thisresulted in unrecognized inaccuracies in the nuclear plant PMF calculations.

• Nuclear Power Group management failed to ensure a sufficient focus on nuclearsafety with regard to flooding by failing to provide effective oversight andengagement on changes being made to the river system in order to ensure thatpotential impacts on the WBN flooding design basis were properly evaluated.

• Formal flood protection programmatic and process controls had not been established for the protection of critical safety systems at WBN.* Nuclear Power Group personnel had less than adequate common internalunderstanding of the applicable regulatory requirements for WBN with respect toriver system operation controls.

• Ineffective completion of the Bellefonte Nuclear Plant corrective actions.Corrective Steps That Have Been Taken and Results AchievedThe installation of HESCO barriers on the Fort Loudoun,

Tellico, Watts Bar, and Cherokeedams has been completed to raise the effective height of the earthen embankments.

Post-HESCO PMF calculations have been issued for WBN to bring WBN into compliance with the licensed conditions.

An Integrated Hydrology Advisory Committee has been implemented.

The committee wasformed to identify,

discuss, and disposition common issues and initiatives relating to TVAhydrology.

In addition, the implementing procedure, TVA-SPP-20.009, "Coordination ofHydrology Issues,"

has been issued. This procedure applies to TVA organizations.

Issuesand initiatives relating to TVA hydrology are included in the scope of this procedure.

Procedure NEDP-20, "Conduct of the Engineering Organization,"

has been revised toinclude a Flood Protection Program within the Corporate Nuclear Engineering organization.

The primary function of the Flood Protection Program is to ensure that nuclear plant criticalsafety systems are protected from all postulated flooding conditions.

E2 of 9 Reply to a Notice of Violation; EA-13-018 Corrective Steps That Will Be TakenIn addition to the corrective steps that have already been taken, the following corrective steps remain to be taken." Procedures will be developed or revised to implement the Corporate NuclearEngineering Flood Protection Program described above. The implementing procedures will ensure that nuclear plant critical safety functions are protected frompostulated flooding conditions, and will include appointing a single-point owner,defining roles and responsibilities, and identifying the nuclear regulatory requirements.

• Procedural requirements will be established to include reviews by TVA NuclearPower Group of any river or dam changes, including calculations that may affect theCorporate Nuclear Engineering Flood Protection Program.* A formal risk management

process, informed by Institute of Nuclear PowerOperations (INPO)12-008, "Excellence in Integrated Risk Management,"

for allflood-related engineering products will be created.

The process will ensure changesare evaluated to nuclear plant design standards, river system operations, flood-related procedures, project management procedures, and applicable environmental standards.

• An inventory of nuclear programs and processes that are important to nuclear safetywill be developed.

The programs and processes will be prioritized in order of relativerisk or importance to safety, and controlling procedures to assure nuclear safety willbe verified to exist. This inventory of programs and processes will be reviewed on abiennial basis and updated, as necessary.

Date When Full Compliance Will Be AchievedFull compliance was achieved on December 30, 2009 for the failure to establish and/ormaintain an adequate Abnormal Operating Instruction procedure to implement its floodmitigation strategy violation as described in EA-13-018.

On this date the HESCO barrierinstallation was completed to raise the effective height of the earthen embankments and thepost-HESCO PMF calculation was issued for WBN, placing WBN in compliance with thelicensed conditions.

E3 of 9 Reply to a Notice of Violation; EA-13-018 Restatement of Violation BTechnical Specification 5.7.1, Procedures,

requires, in part, that written procedures shall beestablished, implemented, and maintained covering the activities recommended inRegulatory Guide 1.33 [Quality Assurance Program Requirements (Operations)],

Revision 2,Appendix A, February 1978.Regulatory Guide 1.33, Revision 2, Appendix A, includes "Abnormal Conditions" as a typicalsafety-related activity that should be covered by written procedures.

Abnormal Operating Instruction AOI-7.1, "Maximum Probable Flood," Revision 21, and thesupporting maintenance instructions referenced

therein, required that the plant bereconfigured and systems realigned within 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />, consistent with Technical Requirements Manual (TRM) 3.7.2 and Watts Bar UFSAR [Updated Final Safety AnalysisReport] Section 2.4.Contrary to the above, the licensee failed to maintain an adequate Abnormal Condition procedure to implement its flood mitigation strategy.

Specifically, the licensee was unable toimplement AOI-7.1 to reconfigure and realign systems necessary for flood mitigation within27 hours. As a result, the licensee's flood mitigation strategy for certain flooding events,including PMF events, was inadequate.

This condition existed from initial licensing until July2012.Background From August through September, 2012, WBN performed a Reasonable Simulation ofAbnormal Operating Instruction (AOI) 7.01, "Maximum Probable Flood," and relatedimplementing procedures as a part of a NRC Near Term Task Force (NTTF)Recommendation 2.3 inspection.

Procedure AOI-7.01 contains the requirements to meetTRM 3.7.2, "Flood Protection Plan," and WBN UFSAR Section 2.4. The activities aredivided into two stages designated Stage I and Stage I1. Stage I actions are essentially preparatory in nature for the plant site to receive flooding levels above plant grade. Theseinclude shutting down the reactor and commencing cool down to 350 degrees Fahrenheit and moving equipment.

Stage I actions are to be complete within 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of thedetermination that Stage I actions should be implemented.

Based on communications withTVA River Operations, WBN remains in Stage I until River Operations determines that floodlevels may reach plant grade level. If River Operations determines that flood levels mayreach plant grade, Stage II is entered and significant plant system realignments occurincluding connecting:

the Essential Raw Cooling Water (ERCW) System to the Component Cooling System (CCS); the ERCW to the Raw Cooling Water (RCW) System; the FireProtection System to the Auxiliary Feedwater (AFW) System; and in some plant conditions, spent fuel pool (SFP) cooling to the Residual Heat Removal (RHR) System. Theseconnections are made with spool pieces that are staged at various locations throughout theplant. Stage II actions are to be completed within 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br /> of the determination that Stage IIshould be implemented.

Thus, a total of 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> are allowed to complete the Stage I andStage II actions.E4 of 9 Reply to a Notice of Violation; EA-13-018 During the Reasonable Simulation, WBN could not demonstrate that completion of tasksrequired to realign the plant for flood mode operation could be achieved within the 27 hourrequirement specified by TRM 3.7.2 and UFSAR Section 2.4 for the PMF event.The direct cause of this condition is that the number of personnel

required, staging of toolsand equipment, and staging of materials have not been maintained for optimumimplementation of flood mode operation which resulted in the inability to demonstrate performance of the actions in the time required by the UFSAR Section 2.4.Reason for the Violation The reasons for this violation are as follows." Failure of WBN personnel to understand the risk significance of issues identified withthe station's ability to implement the flood mode protection plan. This resulted inWBN personnel not questioning the assumptions for success nor the need tovalidate the flood mode response timeline.

" Use of unsubstantiated assumptions related to the number and type of personnel required to perform the actions required by TRM 3.7.2 and UFSAR Section 2.4 andthe actual time necessary to perform the actions." Failure to thoroughly evaluate missed opportunities identified by line personnel, TVA's Quality Assurance organization, and by the NRC.* Failure to properly train and maintain proficiency of the workers who perform theflood control procedures.

This resulted in unfamiliarity with the challenges andactions required to optimize implementation of flood mode operations.

• Belief in WBN personnel capabilities to implement flood mode procedures as written.This resulted in a low priority being placed on concerns identified related to timelyimplementation of flood mode operations.

Corrective Steps That Have Been Taken and Results Achieved* The implementing instructions, AQIs, and Maintenance Instructions (MIs) have beenrevised to capture the lessons learned from the performance of the Reasonable Simulation of AOI-7.01.

" A timeline has been created and incorporated into AOI-7.01 to provide amanagement tool for implementing the flood mode plan in the required sequence.

• A detailed listing of tools and equipment required for implementing each naturaldisaster-related MI has been incorporated into the procedures.

Flood mode toolboxes have been staged, locked, and clearly labeled for the particular Maintenance Instruction at the appropriate locations to ensure tools to implement the requiredactions are available.

Periodic inspection/inventory on a quarterly basis is requiredto ensure the tool boxes remain in place and are locked.E5 of 9 Reply to a Notice of Violation; EA-13-018

• Procedure AOI-7.01 has been revised to provide clear guidance to aide inorganizational response.

" Operations requalification training for Flood Mode implementation procedures hasbeen reduced from a 4-year frequency to a 2-year frequency.

• Technical training has completed a training needs analysis to revise and incorporate Flood Mode training for those organizations responding to a PMF event.* Procedure NEDP-20, "Conduct of the Engineering Organization,"

has been revisedto include a Flood Protection Program within the Corporate Nuclear Engineering organization.

The primary function of the Flood Protection Program is to ensure thatnuclear plant critical safety systems are protected from all postulated floodingconditions.

Corrective Steps That Will Be TakenIn addition to the corrective steps that have already been taken, the following corrective steps remain to be taken." Operations Procedure 0-PI-OPS-19.0, "Periodic Assessment of operations Procedures Related to Natural Disasters,"

will be revised to include walkdowns ofnatural disaster-related MIs. The walkdowns will verify that the MIs are accurate, tools and equipment are staged appropriately, and support documentation such asrigging permits and clearances are pre-staged for use.* The results of the completed Flood Mode training needs analysis described abovewill be incorporated into training programs for those organizations responding to aPMF event.* Procedures will be developed or revised to implement the Corporate NuclearEngineering Flood Protection Program described above. The implementing procedures will ensure the nuclear plant critical safety functions are protected frompostulated flooding conditions, and will include appointing a single-point owner,defining roles and responsibilities, and identifying the nuclear regulatory requirements.

Date When Full Compliance Will Be AchievedFull compliance was achieved on November 15, 2012 when flood-related Maintenance Instructions and AOI-7.01 were revised to incorporate lessons learned from the Augustthrough September, 2012 Reasonable Simulation of AOI-7-01.

E6 of 9 Reply to a Notice of Violation; EA-13-018 Restatement of Violation C10 CFR 50.72(b)(3)(ii)(B) states that a licensee shall notify the NRC as soon as practical and in all cases within eight hours of the occurrence of the nuclear plant being in anunanalyzed condition that significantly degraded plant safety.Contrary to the above, on December 30, 2009, the licensee failed to report within eighthours an unanalyzed condition that significantly degraded plant safety for the Watts Bar Unit1 facility.

Specifically, the licensee failed to notify the NRC upon confirmation that apostulated Probable Maximum Flood (PMF) level would exceed the current licensing basisand the design basis PMF flooding event would result in overtopping of critical earthen damstructures upstream of the Watts Bar facility.

These overtopping conditions were notpreviously assumed in the licensing basis for the facility and represented an unanalyzed condition.

Background

It was determined on July 28, 2009, an upstream dam (Fort Loudoun) would overtop and failduring a design basis PMF. Subsequent to this date, it was discovered that Cherokee,

Tellico, and Watts Bar dams had a similar design vulnerability that would also result in ahigher flood elevation at the site. This condition had the potential to exceed the licensing basis PMF levels at WBN and adversely impact safety functions at the plant. The increasein PMF placed the plant in an unanalyzed condition.

Nuclear Power Group personnel failedto recognize that this condition was required to be reported to the NRC by 10 CFR50.72(b)(3)(ii)(B).

During the period from 2010 to present, TVA's communication with the NRC on this issueincluded public meetings, letters and correspondence, License Event Reports, LicenseAmendment

Requests, a Confirmatory Action Letter, and numerous email and telephone communications.

Communication by TVA with the NRC concerning WBN being in anunanalyzed condition (prior to installation of the HESCO barriers) did not take the form of aformal notification by WBN as required by 10 CFR 50.72, until TVA reported the condition inaccordance with 10 CFR 50.72 on February 6, 2013, resulting in impediments to NRCprocesses.

Reason for the Violation The reasons for this violation are as follows.The nuclear processes and procedures failed to lead TVA to realize, in 2009, thatinvalidated assumptions in calculations of PMF levels constituted a reportable unanalyzed condition that significantly degraded plant safety. In the period from2009 through 2012, WVA procedure inadequacies did not require Functional Evaluations to address reportability, nor did reporting procedures fully incorporate regulatory guidance on reportability.

E7 of 9 Reply to a Notice of Violation; EA-13-018

• Nuclear Power Group personnel had a cultural bias towards not reporting events andconditions when the consequences of an event or condition were uncertain and notfully analyzed.

" Nuclear Operations, Engineering, and Licensing personnel were weak inunderstanding unanalyzed conditions and the relationship to reportability.

• An erroneous, centralized decision was made within TVA Corporate NuclearLicensing that the calculated PMF levels and their potential impacts on WBN werenot reportable because of the uncertainties in the calculations.

• Nuclear Power Group personnel failed to adequately challenge the decision that theissue was not reportable.

Corrective Steps That Have Been Taken and Results AchievedAs stated above, TVA made a 10 CFR 50.72(b)(3)(ii)(B) notification on February 6, 2013(Emergency Notification Report 48723).A structured oversight program to assess reportability decisions has been developed.

Thisoversight program requires a review of the reportability determinations of at least 10 percentof the TVA Nuclear Power Group fleet problem evaluation reports (PERs) on a bi-weekly basis.Corrective Steps That Will Be TakenIn addition to the corrective steps that have already been taken, the following corrective steps remain to be taken.* Procedure NPG-SPP-03.5, "Regulatory Reporting Requirements,"

will be revised to:include the requirements of NUREG-1022, Revision 3 and examples of whatconstitutes an unanalyzed condition; include direction to refer to Section 2 ofNUREG-1022 for special conditions on reportability; and ensure that when usingengineering

judgment, conservative decision-making is applied (i.e., if there is doubtregarding whether to report or not, the report should be made)." Procedure NEDP-22, "Functional Evaluations,"

will be revised to address if a defectis outside current licensing basis and/or design basis (i.e., an unanalyzed condition exists).

If such a situation exists, the procedure will provide that the reportability ofthe defect should be determined.

• The above described revisions to NPG-SPP-03.5 and NEDP-22 will be incorporated into Operations, Engineering, and Licensing training.

• Broad scope reportability program training will be conducted for key organizations with reporting responsibilities.

E8 of 9 Reply to a Notice of Violation; EA-13-018

• A case study on hydrology and flooding reporting decision errors will be developed for the INPO Significant Operating Experience Report (SOER) 10-2 trainingconducted this year. Included in the case study will be the dangers of group think,the need for rigor and oversight, and the use of risk in decision making that mayaffect nuclear safety.* The structured oversight program described in the corrective steps that have beentaken will be maintained for a minimum of one year.Date When Full Compliance Will Be AchievedFull compliance was achieved on February 6, 2013 for the failure to report in accordance with 10 CFR 50.72(b)(3)(ii)(B) violation described in EA-13-018, when the event wasreported to the NRC (Event Notification 48723).E9 of 9