ML021140225

Refuel 13, April 8, 2002 Pre-Outage Presentation

ML021140225
Person / Time
Site:	Summer
Issue date:	04/08/2002
From:	South Carolina Electric & Gas Co
To:	Office of Nuclear Reactor Regulation
Shared Package
ML021140207	List: ML021140217 ML021140225
References
Download: ML021140225 (48)

Text

REFUEL 13 April 8, 2002 Pre-Outage Presentation

Agenda

• General Introduction and Plant Status (Greg Halnon)

• Outage Overview (Alan Torres)

- Major Modifications

- Major Maintenance

- Shutdown Safety

• Major Efforts (Gary Moffatt)

- Hot Leg Follow-up

- MSIP

- NRC Bulletin 2002-01

• I&C Modernization (Steven Fipps)

- Main Feedwater Pump Controls

- Alterrex Voltage Regulator

• Closing Comments (Steve Byrne)

Refuel 13 Overview A D Torres, Manager of Outage & Work Controls

Refuel 13

• Duration

- Approximately 33 Days

• Cost

- Budgetary Goal Is $12.3 Million

Refuel 13

• Number 1 Outage Goal

- Safety

• Nuclear

• Industrial

• Radiological

Refuel 13

• Whats in Our Outage (7000 Items)

- Modifications

- Non-conformance Notices /Condition Evaluation Reports

- Maintenance Work Requests

- Preventive Maintenance

- Surveillance Tests

- Support Activities

Refuel 13

• Critical Path

- Shutdown

- RV Disassembly

- Core Off-Load

- CCW Exchanger Repair

- Core Reload

- Startup

Refuel 13

• Modifications

- FWP Digital Controls

- Excitation Upgrade

- MSIP Process

- Reroute of Condenser Transmitter Lines

- RHR Miniflow Switch Relocation

- D/G Day Tank Level Instruments

- D/G Air Start Receiver Relief Valve

Refuel 13

• Modifications

- D/G Fuel Oil Strainer Sensing Lines Redesign

- Replacement of RB Component Cooling Isolation Valve (XVC-9689CC)

- FWP Drain Isolation Valve

- Dynamic Brake for Refueling Bridge

- S/G Cover Modification

- FW Heater Instrumentation Manifold Rework

Refuel 13

• License Amendments

- Amendment 154 - Pressure Isolation Valve Leakage Allowance

- Amendment 155 - Corrects Reactor Trip Settings for Main Steam Safety Valve Testing

- Amendment 156 - Provisions for Performing RTD Cross-calibration With MSIVs Closed

- Amendment 157 - Requires High Flux Reactor Trips Be Operable for Rod Withdrawal in Source Range (NSAL 01-016)

- Amendment 158 - Extends Elimination of Response Time Testing for Additional 7300 Process Cards

Refuel 13

• PRA Review of Modifications

- None of These Projects will Increase the Long Term Risk at VCS

• The DG fuel oil instrumentation and the RHR sensing modifications will have an elevated risk due to major component out of service, but manageable under 10CFR50.65a(4)

Refuel 13

• Major Maintenance Work

- Major FWP Work: 3 Pumps/1turbine

- CCW Heat Exchanger Repair

- 2 Reactor Coolant Pump Seal Jobs

- Repair of Steam Generator Sludge Covers

- Flow Accelerated Corrosion Inspection and Pipe Replacement

- Condenser and Heat Exchanger Cleaning

- Reactor Vessel Head Inspections

Refuel 13

• Potential Issues

- RCS Hot Leg Nozzle Inspection

- FWP Digital Modification

- Scope of CCW Heat Exchanger Repair

- RBCU Testing

- Startup Testing

Refuel 13

• Why Are They Potential Issues

- Schedule Impact High

- Potential Startup Delays

- Repair Scope Unknown

- Personnel Hazard

Refuel 13

• Dealing with Risks

- Contingency Planning

- Potential Repair Plans Developed

- Employing HIT Team Project Mentality

- Evaluating Additional Options

Refuel 13 Relative Risk Profile 9" below flange 6

230 kV 9" below 115 kV Outage flange Outage 5

1 DB Outage flange level 4 230 kV Back in Service, Core "B" Train Offloaded "A" Outage 3

RCS 2 Flooded Up, Intact Depresurrize "A" Train RCS Outage 1 "A" Train "B" Train in 1DB In service Upper Internal In service 115 kV In Installed Core re-loaded service 0 4/20/2002 4/24 4/25 4/28 5/5 5/6 5/7 5/11 5/12 5/14 5/16 5/20 5/18

Reactor Coolant Hot Legs &

Reactor Vessel Head Gary Moffatt, Manager of Design Engineering

B & C Hot Leg Plan:

Mechanical Stress Improvement Process (MSIP)

VC Summer RF 12 Relevant Indications A Loop Hot Leg - New Weld with Alloy 690 Material A,B, &C Cold Legs - WCAP 15615 > 25 years (Low Temperature = Low Stress)

HOT LEG LOOP LOCATION LENGTH ORIENTATION (EDDY CURRENT)

C 309/CIRC 0.5 B 35/CIRC 0.6 B 200.8/AXIAL 0.25 B 348/AXIAL 0.25

B & C Hot Leg NDE Plan

• UT Examination Complemented by ET Examination.

• ET Indications From RF-12 will Be Scrutinized by Axial and Circumferential ET.

• Whole Weld will Be Examined by Circumferential UT and ET.

• Screening Criteria will Be Applied to ET Indications.

• Flaws will Be Characterized by UT.

• Our Expectation: We will See the Same Indications

• NDE Inspection Before & After Mitigation Application

MSIP Principle MATERIALS ENVIRONMENT MATERIALS ENVIRONMENT CONDITIONS FOR STRESS TENSILE STRESS RELATED CRACKING EXIST Sr Sy (a) AS WELDED TENSILE STRESS Sr << Sy (b) AFTER MSIP Removal of Tension Provides Permanent Protection of Weldments Against Stress Related Cracking

Mechanical Stress Improvement Process - MSIP

• MSIP

- Invented, Developed, and First Used in 1986

- Mitigates Stress Related Cracking in Nuclear Reactor Plant Piping Weldments

- Permanently Removes Weld Residual Tensile Stresses and Generates Compressive Residual Stresses

- Displacement Controlled - Verifiable by Measuring Pipe Hoop Contraction

Basic Concept Of MSIP

a. Application of Pressure to Contract Pipe

b. Schematic of Permanent Deformation after MSIP

c. Mechanism of Compression

• Generation in Axial and Hoop Directions

• Deformation in pictures are exaggerated for viewing purposes

V. C. Summer Hot Leg Nozzle Weld Region V. C. Summer Hot Leg Nozzle As-welded Residual Stress (Axial)

V. C. Summer Hot Leg Nozzle Weld Post-MSIP Residual Stress (Axial)

MSIP Experience

• Used Since 1986 on Over 1300 Welds Including more than 500 Nozzle and Safe-End Welds in Over 30 BWR Units Worldwide

• Applied to Welds Without and With Stress Corrosion Cracks

• No Indications Found in Treated Welds

• Pre-existing Cracks Arrested; No Crack Growth after MSIP During Subsequent Fuel Cycles

• Verified by Argonne National Laboratory and EPRI for Pipe Specimens and Nozzle Specimens Without and With Cracks

MSIP Acceptance Criteria And Repair Contingency

• Nureg 0313 Acceptance Criteria

- < 10% of the Circumference

- < 30% of the Wall Thickness

• Code Repairs for Flaws > MSIP Acceptance Criteria

- Localized Repair

- Weld Replacement

- Spool Piece Replacement

• MSIP After Code Repair

MSIP Qualification Mock-up For VC Summer Rigging Upper Clamp Into Position MSIP Clamp In Place In VC Summer Mock-up Hot Leg Surface After Qualification Test Hot Leg Plan Conclusions

• Inspection Plan Is Sound / Effective

• MSIP - Effective Aging Management Preventive / Mitigative / Repair Process for the B & C Hot Legs

• Arrangements With NRR for Rapid Inspection Results Communication and SER Turn Around

NRC Bulletin 2002-01 Reactor Vessel Head Degradation

• Vessel Head Inspection & Maintenance Programs -

Defense in Depth

• Corner Stone: Prevent / Manage Leaks Above the Head

• Programs Have Been Effective & Meet the Regulatory Requirements

• Very Low Susceptibility to CRDM Penetration Cracking

• 2 Very Minor Conoseal Leaks W/ Minor Boric Acid

• No Boric Acid on the Insulation or Head

• Best Effort Remote Visual Inspection Under the Insulation in RF 13

Refuel 13 I&C Modernization Steven F. Fipps, Design Engineering Supervisor &

I&C Modernization Committee Chairman

Driving Issues

• Reliability and Availability

• Operating Costs

• Obsolescence

• Improved Operational Performance

• Staff Utilization

Modernization History Phase I

• Start With BOP NNS Systems

• Choose a Standard Platform

• Identified Training Needs

• Establish Implementation Schedule

• Apply Lessons Learned

Implemented Digital Control Modifications

• Turbine Building Closed Cycle Cooling

• Moisture Separator Reheater Controls

• Feedwater Heater Vents and Drains

DCS Modifications Lessons Learned

• No Problems With Digital

• Improved Problem Identification and Resolution

• Improved Control & Mitigation of Transients/events

• Fewer Initiating Events

• Improved System Redundancy

• Operator Simulator Training - High Priority

Refuel 13 I&C Modernization

• Main Feedwater Pump Digital Speed Control

• Main Electrical Generator Alterrex Digital Voltage Regulator

• Feedwater Heater Vents and Drains Instrumentation Manifold (Follow-up)

Main Feedwater Pump Digital Speed Control Why

• Obsolescence of Existing Controls

• Maintenance Cost Increasing

• System Reliability What

• Replace Analog Controller With Bailey (ABB)

INFI-90 Digital Control System

• Replace Mechanical Controller With Hydraulic Servo Actuator

• Upgraded Turbine Supervisory Instrumentation

• Upgrade FWP Re-circulation Valve Control

Main Feedwater Pump Digital Speed Control (Benefits)

• Improved Operator Controls and Indication

• Reduced Maintenance Cost

• Improved Reliability & Availability

• Improved Operational Performance

• Improved Human Factors

• Improved Problem Identification

• Improved Mitigation of Events

Main Electrical Generator Alterrex Digital Voltage Regulator Why

• Obsolescence of Existing Controls

• Maintenance Cost Increasing

• System Reliability

• Operational Performance What

• Replace GE Analog Alterrex Voltage Regulator With a GE Digital Alterrex Voltage Regulator

Main Electrical Generator Alterrex Digital Voltage Regulator (Benefits)

• Improved Problem Identification

• Reduced Maintenance Cost

• Improved Reliability & Availability

• Improved Operational Performance

• Improved Human Factor

Feedwater Heater Vents And Drains Instrumentation Manifold (Follow-up)

Why

• System Reliability

• Operational Performance What

• Re-pipe the Instrumentation Manifolds

• Replace Globe Valves With Ball Valves

Feedwater Heater Vents And Drains Instrumentation Manifold (Benefits)

• Reduced Maintenance Cost

• Improved Reliability & Availability

• Improved Operational Performance

• Improved Mitigation of Events

I&C Modernization Phase II

• Control Room Review

• Main Turbine EHC Control

• Radiation Monitoring

• Moduflash Control Room Display Unit

• Plant Process Computer

• DA/hotwell Level Control

• ESF D/G Digital Controls

• Digital Rod Position

• 7300 Process Racks (ASICS)

Closing Remarks Steve Byrne, Senior Vice President of Nuclear Operations