ML032040613

Plant Performance

ML032040613
Person / Time
Site:	Sequoyah
Issue date:	07/09/2003
From:	Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
References
Download: ML032040613 (28)

Text

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Sequoyah Nuclear Plant Plant Performance v Jji1jyvi WVA/NRC Meeting Region It, Atlanta Ga July 9, 22003 r

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• Introduction

• Plant Performance

• Steam Generator Replacement Outage R. T. Purcell D. L. Koehl Overview Ulchin 4 (Korea) Operating Experience RPV Head Inspections RCS Debris Startup Testing Occupational Radiation Safety

• Equipment Reliability Improvement Plan Objective/ Immediate Actions Process Culture Hardware Outage Improvements P1l

• Corrective Action Program

• Licensing

• Conclusions R. R. Rausch R. R. Rausch D. L. Lundy D. L. Lundy D. L. Lundy C. E. Kent D. L. Koehl M. Gillman M. Gillman D. L. Lundy D. L. Lundy D. L. Lundy D. L. Koehl P. Salas R. R. Purcell I

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March 17, 2003 UIC12 Steam Generator Replacement and Refueling Outage I

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1. April 12, 2003

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March 10, 2003

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March 24, 2003

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December 26, 2002

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July 12, 2002

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May 31, 2002

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May 19, 2002 B.

April 14, 2002 U2C11 Automatic Reactor Trip Manual Reactor Trip Unit 2 Forced Outage Automatic Reactor Trip Automatic Reactor Scram Automatic Reactor Trip Manual Reactor Trip Refueling Outage Spurious Turbine Vibration Trip Signal Trip of a Hotwell Pump and Heater Drain Tank Pumps Main Generator Hydrogen Leak Loss of a Reactor Coolant Pump Bus Undervoltage to Reactor Coolant Pumps Loss of Stator Cooling Water Rod Control Urgent Failure Shutdown Bank B and Control Bank D (Occurred during power ascension following the U2C1 1 Refueling otage before tie onto grid)

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)4 Q1 00 02 03 Unit2 Q4 Q10 1 02 03 Q4 Q1 02 02 03 04 01 03 INDUSTRY MEDIAN SQN UiT ISQN UtNIT 2 MAY 2003 PERFORMANCE INDICATOR WEIGHT VALUE INDEX PRODUCr VALUE INDEX PRODUCT Unit Capability Factor (18 MNTH) 0.16 85.9 67.8 10.9 86.5 72.1 11.5 Forced Loss Factor(18 MNTH) 0.16 0.2 100.0 16.0 7.1 36.4 5.8 Unplanned Automatic Scrams (24 MNTH) 0.10 0.000 100.0 10.0 1.700 25.5 2.6 Safety System Performance:

PWR High Press. Inj. (3 YR) 0.10 0.003 100.0 10.01 0.004 100.0 10.0 PWR Aux. Feedwater (3 YR) 0.10 0.005 100.0 10.01 0.004 100.0 10.0 Emergency AC Power (3 YR) 0.10 0.017 100.0 10.0 0.017 100.0 10.0 Fuel Reliability (Most recent qtr) 0.11 0.0000 100.0 11.0 0.0052 0.0 0.0 Chemistry Indicator (18 MNTH) 0.0 1.00 100.0 701 102 1000(

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Collective Rad. Exposure (18 MNTH) 0.10 193.85 4.6 05:

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INPO PERFORMANCE INDEX 853 66.1

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• Steam Generator Replacement Project Successful Performed Heavy Load Lifts and Implemented Compensatory Measures Plant Restoration Completed as Expected Start-up Testing

• Low Power Testing Complete with Satisfactory Results

• Higher Power Level Load Rejection Testing Scheduled for July 2003 i

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• Sequoyah and Ulchin 4 SGs have different features

• Hydraulic expansion employed to avoid explosive expansion problems

• Profilometry (1 00-percent of the tubes) revealed no bulges

• Tube Exams 100% of tubes examined with a bobbin coil probe 100% of the U-bend region tubes in Rows 1 through 3 with a +Point coil 100% of the top of tubesheet region (+3-inches to inches) hot-leg tubes with a

+Point coil Approximately 100 special interest locations examined with a +Point coil.

• Sequoyah does not have the same conditions present in Ulchin 4 Ulchin 4 Sequoyah Tube Material Alloy 600 Alloy 690 Tube Manufacturer B&W Special Products Sandvic Tube Expansion into Explosive Hydraulic Tubesheet I

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• Top Head Completed remote camera bare of the head and penetrations on Inspections identified boric acid No. 3 metal visual inspection of 100%

Units 1 and 2 deposits on Unit 1 at penetration Full volumetric inspection performed on 6 Unit 1 penetrations (Nos. 3, 53, 64, 65, 72, and 73); no indications identified Dye penetrant test performed on Unit 1 penetration No. 3 at the J-groove weld; no indications identified Repeat bare metal visual inspections scheduled for every 3rd refueling outage or 5 Years (whichever is first)

Volumetric examination of head penetrations scheduled for U2C14 and U1C15 Repeat volumetric examinations scheduled for every 4th refueling outage or 7 Years (whichever is first)

Completed Unit 1 head cleaning; better baseline for future inspections.

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• Bottom Head Completed remote camera visual inspection of the Unit 1 bottom head and penetrations Inspection identified 2 streaks from the upper compartment Streak areas were cleaned and no surface indications found No indications found on bottom head penetrations Unit 2 bottom head inspection is scheduled for the upcoming Cycle 12 refueling outage i

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• 26 Crescent shaped objects identified in the Reactor Pressure Vessel (RPV) 19 objects removed from RPV 7 objects remain below the lower core plate of the RPV

• 1 Dowel pin observed and remains below the lower core plate of the RPV

• 1 Cap screw observed and remains below the lower core plate of the RPV

• 6 Crescent shaped objects removed from 139 fuel assembly filter nozzles Debris Captured By Filter Nozzle Typical Object Shape i

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• Analysis indicates material is Type 302 or Type 304 spring tempered austenitic stainless steel

• Objects appear to be part of a helical spring

• Source paths and each component in those systems evaluated. Major components such as the emergency core cooling system (ECCS) pumps eliminated as a source. Foreign objects appear to be from maintenance tooling

• The fracture surface of several pieces representative of fatigue failure Spring entered the bottom of the reactor pressure vessel at some time after the last core barrel removal, at the end of Cycle 6. Pieces were lodged against the fuel for a minimum of 88 to 106 days During operation, the spring impacted the lower head, core barrel supports, and fuel assembly bottom nozzle filters. At some point, during Cycle 12 operation, the spring broke into segments that were trapped by the fuel assembly bottom filters

• Completed an operability analysis which considered as found conditions and potential effect from those objects that were not removed

• Debris filters worked as designed

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• Major Tests Completed Steel containment vessel pressure test @ rated pressure Thermal expansion, hot shimming RCS, FW, MS pipe vibration RCS flow test @ NOTP and @ 100% Power 3% load reduction test @ 40% reactor power Calorimetric @100% power

• Major Tests Remaining 10% and 20% load reduction tests @ 85% reactor power: 7/12 Moisture carryover (MCO) test: 7/30 I

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• Measured dose rates were 20% to 30% lower than U 1 C 1 1 due to source-term reduction initiatives

• Nearly 300,000 pounds of temporary shielding installed

• Total collective radiation exposure over target as result of outage scope expansion Planned Scope 250.0 REM Planned Scope Actual 246.4 REM Added Scope (e.g, Head on Stand, Head Inspections, Core Plate Debris) 47.5 REM Total Outage Actual 293.9 REM

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• Equipment reliability challenged recent Unit 2 operation Unit 1

• Unit 2 challenges followed a 513 days continuous run Unplanned Scrams per 7000 CrItical Hrs

• Unit 1 completed a breaker to breaker run (478 Days) prior to SG replacement outage 0O 5

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• Equipment reliability improvements implemented during Unit 1 outage to insure sustained performance Thl od' Wt.' 3O Y04 > 6 Rnd' 25M Unit 2

• Sequoyah developed and is implementing an Equipment Reliability improvement Plan Unplanned Scrams per 7000 Critical Hrs i

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• Our Objective:

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Unit 1 - good post-SG replacement operation T1n.o4dr be o' 3.0 YalOW >8. Red'> 25.

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• Focus Process Culture Hardware

• Senior VP Operations led corporate assessment

• INPO senior level assist visit

• Pll risk informed review of equipment reliability - trip sensitive component project I-.I

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m Immediate Actions Develop a Sequoyah Reliability Improvement Plan to integrate site efforts to immediately improve reliability Increase field oversight of the Transmission Power Supply (TPS)

Improve the sensitive activities review process Immediately raise standards Ensure reliable operation once Unit 1 returns to service

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I11 AI Process Specific process improvements or barriers have been addressed as a result of specific event root cause analysis INPO high-level assist visit, drawing on the strength of the industry, to improve rigor of equipment reliability programs, including recommendations on the implementation of AP-913, Equipment Reliability Process Description Strengthening the forum for system health reviews with management team

• Transform system health reviews to be forward looking as opposed to critiques

• Assure planning process places correct priorities to equipment reliability I

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Culture Limited success recognizing and symptoms of pending equipment identifying early warning failures Equipment aging will be a continuous challenge Change behaviors to better predict, recognize, and identify early warning signs of equipment failure Major departments have implemented self-critiques of their current behaviors that have failed to identify symptoms of impending equipment failure Action plans to change behavior (INPO team assistance)

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Hardware Identify specific lessons learned on equipment reliability issues Maintenance Corrective action program System health programs Prioritized equipment reliability maintenance and design changes to take advantage of the longer steam generator replacement outage Industry expert performing risk informed evaluation to identify components that impact equipment reliability Results of industry expert review (expected to take three to five months) will provide immediate output on identifying any issues or actions warranted on a component-by-component basis I-.

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Original Scope Added Scope Added Scope Major Design Changes Design Changes Maintenance

• Feed Pump Modifications

• ECCS High Point Vents

• Large Motors

• Heater Drain Tank

• Feed Pump Modifications

• MSIV's Modifications

• Condensate Booster Pumps

• Main Feed Pump and Heater

• CCW Pump Motor Bearing and the #3 and #7 Heater Drain Tank Pumps Cooler Piping Modifications Drain Tank Pumps Flex

• Corrected 129 Boron Leaks

• Start Bus Transfer Interlock Couplings

• Inspected Unit Trip Sensitive

• Exciter Cooling System Piping

• Reactor Coolant Pump Seal Drawers for Wire Damage and Control Valves Leak-off Drain

• Electrical Penetrations

• Main Turbine Vibration Trip Relay

• Hand Switches for Critical

• Heater Drain Tank Level Safety Related Motors Controllers

• CRDM Duct Expansion Joints

• TDAFW Pump Low Pressure

• EHC Controls Steam Traps

• Generator Hydrogen Flow Integrators

• High Pressure Rotor on Main Turbine I

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Planned Scope Additions Planned Scope Additions Design Changes Major Maintenance

• ECCS High Point Vents

• Large Motors

• Feed Water Pumps

• Main Feed Pump and Heater Drain

• Condensate Booster Pumps and #7 and Tank Pumps

1. 8 Heater Drain Tank Pumps

• Main Turbine Vibration Trip Relay MSIV's

• Heater Drain Tank Controllers

• Inspected Unit Trip Sensitive Drawers

• TDAFW Pump for Wire Damage

• Inspect/replace Cast Iron Henry Pratt Valves I*

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• Identifies trip sensitive components that can affect PI related to # of trips per 7,000 hrs

• Focuses on age dependent failure modes that affect equipment reliability

• Analyzes both industry and Sequoyah specific vulnerabilities

• System Engineering develops Prevention, Detection & Correction (PDC) activities to significantly increase reliability

• Extensive Operating Experience review, including -1200 EPIX Failure Reports & LERs

• Identified - 650 events for further applicability analysis by Sequoyah System Engineering

• Results to date identified areas for improvement Nuclear Instrumentation Main & Service Transformers EHC Voltage Regulator 1-.

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i -a Projected Unit 2 Trend Unplanned Scrams per 7000 Critical Hours (Fall Refueling Outage)

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E Corrective Action Program (CAP)

• Efforts to increase craft and technician engagement with the CAP have been effective

• Increased PER generation per month

• Key Initiatives Established department backlog health bands and monitor performance Develop action plans and milestone schedules for resolving issues Re-allocated resources to support work-off plans Instituted review boards for CAP/closure documentation quality Reviewed open A, B and C level PERs to ascertain which are related to unit reliability issues (i.e., trip potential, transient potential or shutdown LCO less than or equal to 72 hrs.)

Continue to communicate to plant staff the value of the CAP

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• Concluding Construction Phase of Project

• Administrative and Technical Procedures in Development Regulatory Evaluations and Reviews Training Lesson Plans

• Equipment Procurement and Receipt on Site is Ongoing Multi Purpose Canister Received on Site Over-pack Receipt Scheduled for 8/2003 Crawler Receipt Scheduled for 11/2003 Auxiliary Building Cask Egress Pad Off Loading of MPC and Up-Ender I..I E

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• Lessons Learned Validate use of correct NOED checklist revision Risk neutrality

• Careful integration of every potential risk increase

• Compensatory measures provide the best counterbalance to increases in risk

• Compensatory measures do not have to be limited to the area of concern that created need for NOED

• TVA has compiled available operating experience to aid in future requests

• Communication Protocol Early communication with resident inspectors if anticipating potential need Schedule preliminary conference call

• Describe condition and basis for request

• Explain risk neutrality arguments and associated compensatory arguments under consideration

• Identify basis for NOED duration Telephone conference call requesting NOED

• Only one opportunity to get risk neutrality argument right

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