ML031770429
| ML031770429 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/07/2003 |
| From: | FirstEnergy Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2003-0376 | |
| Download: ML031770429 (36) | |
Text
Davis-Besse Nuclear Power Station Resolution of Design Issues 1
avis-Besse ar Power Station May 7, 2003
Agenda pening Remarks . . . . . . . . . . . Gary Leidich
- Design Reviews..... Bob Schrauder
- Remaining Design Issues... Jim Powers osing Comments.... Gary Leidich 2
avis-Besse ar Power Station May 7, 2003
Opening Remarks Gary Leidich Executive Vice President - FENOC 3
avis-Besse ar Power Station May 7, 2003
Overview
- Background
-Developed Building Block approach summer 2002
-System Health Assurance, Program Compliance and Containment Health all produced questions relevant to the design of the plant
-December decision to perform additional reviews, including Safety Function Validation Project (SFVP)
-Extensive effort included calculation reviews, detailed design reviews, revalidation of design inputs, and SFVP
- Today
-Present overall results and conclusions
-Discuss few remaining issues and resolution plans 4
avis-Besse ar Power Station May 7, 2003
Desired Outcome
- Demonstrate to the regulators and the public that FirstEnergy has provided reasonable assurance that systems at Davis-Besse can perform their safety and accident mitigation functions 5
avis-Besse ar Power Station May 7, 2003
Return to Service Plan Restart Overview Panel Reactor Head System Health Resolution Plan Assurance Plan Program Compliance Restart Test Plan Plan Restart Action Plan Management and Containment Health Human Performance Assurance Plan Excellence Plan 6
avis-Besse ar Power Station May 7, 2003
Design Reviews Bob Schrauder Director - Support Services 7
avis-Besse ar Power Station May 7, 2003
Design Reviews urpose
-Provide assurance that the safety function of those systems which have a significant contribution to Core Damage Frequency and Large Early Release Frequency (>99%) would perform their safety and accident mitigation functions eviews performed
-Latent Issue Reviews (5 systems)
-Safety Function Validation Project (10 systems) 8 avis-Besse ar Power Station May 7, 2003
Design Reviews Performed atent Issue Reviews
-Reactor Coolant System
-Auxiliary Feedwater System
-Component Cooling Water (CCW) System
-Emergency Diesel Generators
-Service Water System 9
avis-Besse ar Power Station May 7, 2003
Design Reviews Performed afety Function Validation
-Main Steam System
-Steam Generators
-Safety Features Actuation System
-Steam and Feedwater Rupture Control System
-High Pressure Injection System
-Decay Heat Removal/Low Pressure Injection (LPI) System
-Heating, Ventilation and Air Conditioning (HVAC) of Emergency Core Cooling System
-4160 Volt AC
-480 Volt AC
-125/250 Volt DC 10 avis-Besse ar Power Station May 7, 2003
Current Status afety functions confirmed
- Main Steam System
- Service Water System
- Safety Features Actuation System
- Reactor Coolant System 11 avis-Besse ar Power Station May 7, 2003
eam and Feedwater Rupture Control System echnical Specification trip setpoint value for reverse ifferential pressure is non-conservative relative to the esign Basis Calculation ctual field setpoint was conservative relative to the Design asis Calculation, but did not account for instrument ncertainty
- In accordance with NRC Administrative Letter 98-10, Dispositioning of Technical Specifications That Are Insufficient to Assure Plant Safety, administrative controls will be in place to assure compliance with Design Basis pending revision to the Technical Specification solated occurrence bounded by Safety Function Validation roject 12 avis-Besse ar Power Station May 7, 2003
Auxiliary Feedwater System umps and piping may be subjected to a lower temperature an analyzed (8o F difference)
Reanalysis to be performed post restart Acceptability highly likely strument uncertainty for pump flow acceptance criteria not rmally documented Calculation verifying no impact is in final review 13 avis-Besse ar Power Station May 7, 2003
Component Cooling Water System low test verifying adequate flow to minor flow paths has ot been performed System flow test scheduled prior to Mode 4 Demonstration of adequate flow is expected ir Operated Valve deficiencies may impact system perability 14 avis-Besse ar Power Station May 7, 2003
ecay Heat Removal /Low Pressure Injection System PSH and potential vortexing issues related to boron recipitation control Additional testing and analysis nearing completion Function capability expected to be demonstrated Modification to add additional method of boron precipitation to be implemented prior to restart mpact of sump debris on pump seal being evaluated low test demonstrating system margin scheduled prior to estart ir Operated Valve deficiencies may impact system perability 15 avis-Besse ar Power Station May 7, 2003
Emergency Diesel Generators oltage and frequency drop during first load step Transient analysis demonstrating acceptability in review oom temperature may exceed maximum analyzed value New analysis demonstrating past operability in review Additional ventilation to be installed 16 avis-Besse ar Power Station May 7, 2003
High Pressure Injection System ump debris could potentially result in pump damage during ecirculation phase otor exceeds its nameplate rating during accident onditions Preliminary evaluations indicate the motor will remain within its service factor range and will be acceptable nconsistencies between Surveillance Test criteria and echnical Specification requirements Acceptance criteria clearly satisfies accident analysis Acceptable flow demonstrated; instrument uncertainties are being incorporated and are expected to be acceptable 17 avis-Besse ar Power Station May 7, 2003
ECCS-HVAC istorical operability justification with one cooler in service awed otential impact on past operability only 18 avis-Besse ar Power Station May 7, 2003
Electrical Distribution Systems 4160 Volt AC; 480 Volt AC; 125/250 Volt DC
- Reanalysis is incomplete 19 avis-Besse ar Power Station May 7, 2003
Topical Area Reviews urpose
- Evaluate cross-cutting generic issues that could affect multiple systems cope
- Seismic Qualification
- Station Flooding
- High Energy Line Breaks (HELB)
- Environmental Qualification (EQ)
- Appendix R - Safe Shutdown Analysis 20 avis-Besse ar Power Station May 7, 2003
Topical Area Reviews Appendix R - Safe Shutdown Analysis ctions to Support Restart
- Complete Framatome analysis to rebaseline Appendix R transient analysis
- Complete necessary procedural revisions resulting from new analysis
- Complete analysis for Emergency Diesel Generator, Component Cooling Water System, and Service Water System for Appendix R scenarios
- Evaluate technical adequacy of calculations performed in response to Requests for Assistance
- Complete procedure upgrade project for Safe Shutdown procedures
- Train operators on new procedures uture Improvements
- Revise Fire Hazards Analysis Report, as necessary 21 avis-Besse ar Power Station May 7, 2003
Topical Area Reviews Summary of Results ollective Significance reviews confirmed that the programs ere adequate to support safe plant operation ach review identified discrepancies which needed to be solved xtent of Condition reviews were performed where warranted sues appropriately dispositioned as restart or post-restart 22 avis-Besse ar Power Station May 7, 2003
Summary of Results of Design Reviews afety functions confirmed for a number of systems ngoing activities expected to confirm operability of other ystems ome systems were inoperable
- Corrective actions are being taken
- Conditions are isolated or bounded 23 avis-Besse ar Power Station May 7, 2003
Remaining Design Issues Jim Powers Director - Davis-Besse Engineering 24 avis-Besse ar Power Station May 7, 2003
Remaining Design Issues Restart Readiness rovide assurance that
-Safety issues are resolved
-Technical Specification operability is met
-Systems, structures, and components will perform their safety functions ignificant design issues requiring completion of corrective ctions for restart
-High Pressure Injection Pumps Recirculation Mode
-Electrical Distribution System
-Air Operated Valves
-Emergency Diesel Generator Loading 25 avis-Besse ar Power Station May 7, 2003
High Pressure Injection Pumps Recirculation Mode
- Issue
- Fine debris from containment emergency sump could potentially result in damage to pumps during the loss-of-coolant accident recirculation mode
- Resolution Options
- Modify and test existing pumps to ensure operability
- Install new pumps and motors
- Extent of Condition
- Low Pressure Injection Pumps Cyclone Separator
- Containment Spray Pumps High Pressure Injection Pump 26 avis-Besse ar Power Station May 7, 2003
Electrical Distribution System
- Issue
- Condition reports questioned the analysis of the electrical distribution system
- Resolution
- Revalidate input to the analysis
- Reanalyze calculations using updated computer software to meet industry standard
- Validate results to ensure electrical distribution system meets its safety functions
- Extent of Condition Electrical Breaker Cabinet
- 4160V AC, 480V AC, and 125/250V DC systems 27 avis-Besse ar Power Station May 7, 2003
Air Operated Valves
- Issue
- Air Operated Valves (AOVs) have design basis issues related to calculations and hardware
- Resolution
- 19 valves potentially had negative margin
- Adjust 7 valves (prior to restart)
- Modify12 valves (prior to restart)
- 10 valves to have margin increased (post-restart)
- 54 valves demonstrated sufficient margin
- Extent of Condition
- Safety significant AOVs included in program Air Operated Valve - Motor Operated Valves addressed by GL 89-10 Program 28 avis-Besse ar Power Station May 7, 2003
Emergency Diesel Generator (EDG) Loading
- Issue
-EDG loading analysis not updated
-EDG starting voltage and frequency response not in accordance with design and licensing basis
- Resolution
-Revise EDG loading calculation
-Prepare transient analysis for EDG voltage and frequency response and evaluate impact on safety functions
-Evaluate results to ensure the EDGs will meet design basis load requirements
- Extent of Condition Emergency Diesel Generator -Adequacy of design calculations being addressed 29 avis-Besse ar Power Station May 7, 2003
Remaining Design Issues Conclusion esolution of the remaining design issues is being addressed the Corrective Action Program and will ensure safe and liable operation 30 avis-Besse ar Power Station May 7, 2003
.54(f) Design Basis Information Letter Responses
Background
esponse credited calculation improvement programs and stem design description projects of mid-1980s xcluded Topical Areas due to previous assessments and spections
-Environmental Qualification
-High Energy Line Breaks
-Seismic Analysis
-Flooding itiated a Design Basis Validation Program 31 avis-Besse ar Power Station May 7, 2003
.54(f) Design Basis Information Letter Responses
Background
esign Basis Validation (DBV) Program reviews were rformed ograms completion was defined as capturing open items r disposition in:
-Corrective Action Program
-Corrective Action Tracking System
-DBV Program Tracking Database 32 avis-Besse ar Power Station May 7, 2003
.54(f) Design Basis Information Letter Responses Issues ompletion of open items (e.g., calculations) had less than equate priority ollectively the System Health Readiness Reviews (SHRR),
atent Issue Reviews (LIR), and Safety Function Validation oject (SFVP) provided a different and more incisive sessment of the design basis
- Found similar weaknesses in design basis calculations
- Design basis was largely found to be adequate to support operability 33 avis-Besse ar Power Station May 7, 2003
.54(f) Design Basis Information Letter Responses Summary BV Program was completed to the extent defined in the sponses (i.e., placed into a tracking system) ollow-up items have been dispositioned or placed in the orrective Action Program BV Program provided significant value relative to the cumented review of the design bases HRR, LIR, and SFVP have substantiated the design basis as adequate to support operability apture the results of current reviews and submit 50.54(f) esign Basis Information supplemental letter to NRC 34 avis-Besse ar Power Station May 7, 2003
Closing Comments Gary Leidich Executive Vice President - FENOC 35 avis-Besse ar Power Station May 7, 2003
Conclusion ased on the extensive Latent Issues Reviews, focused self-ssessments, Safety Function Validation, Topical Area eviews, containment inspections, and program reviews, here is reasonable assurance Davis-Besses systems will be ble to perform their intended safety functions upon ompletion of the remaining defined activities 36 avis-Besse ar Power Station May 7, 2003