ML061670325

Public Meeting Licensee Presentation Slides for Quad Cities End-of-Cycle Plant Performance Annual Assessment

ML061670325
Person / Time
Site:	Quad Cities
Issue date:	06/14/2006
From:	Tulon T Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
References
Download: ML061670325 (23)

Text

Quad Cities Station Update End-of-Cycle Meeting June 14, 2006 Tim Tulon Site Vice President 1

Topics:

• Extended Power Uprate

- The problem

- The fix

• Radiation Reduction 2

Extended Power Uprate Completed Objective - Increase total generation output on both reactors

• 17% Power Uprate

- Produce 912 megawatts electric

• NRC approval in December 2001

• Initial EPU operation:

- Unit 2 in March 2002

- Unit 1 in December 2002 3

The Problem Increased steam flow Increased acoustic loads Increased Increased steam Steam Dryer line piping loads vibrations Steam Dryer cracks ERV actuator damage 4

Finding the Source

• Unprecedented testing and analysis determined the source of the vibration to the standpipes on the steam lines where the valve attach to the piping.

- The length of the standpipe was increased to reduce the acoustics inside the pipe. --- ERV Similar to tuning a pipe organ, or blowing over the top of a Standpipe soda bottle.

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State-of-the-Art Testing and Analysis Conducted to Validate Vibration Source

• Testing conducted in six states

• Scale models of actual Quad Cities reactor and piping utilized

• Shaker table testing conducted to duplicate actual vibration levels 6

Actions Taken to Correct Vibration Problem

• Installed New Steam Dryers

- More robust

• Installed Acoustic Side Branch Modification

- Retune the steam system

• Installed Upgraded Valve Actuators

- Hardened the actuator 7

New Steam Dryers

• Both Quad Cities steam dryers were replaced in early 2005 with a more robust design:

- Increased stress margins on steam dryers

- Instrumentation provided validation of design load

- Strain gauges provided stress data for analytical purposes 8

2006 Electromatic Relief Valve Upgrade

• Late 2005 issues were discovered with the actuators on the Electromatic Relief Valves (ERVs) due to vibration.

• The ERV actuators have now been replaced with more robust design:

- Several ERV actuator replacement options evaluated. New General Electric design proved to be most rigorous as validated with shaker table tests.

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Shaker Table Testing ERV Actuator Testing ERV Testing 10

New ERV Actuator -vs- Previous New GE Design Previously Installed Design 11

2006 Acoustic Side Branch Modification Removing the Source of the Vibrations 12

2006 Acoustic Side Branch Modification

• Objectives:

- Reduce dryer loading to increase stress margin for long-term operation of dryer

- Reduce overall MSL vibrations impacting ERV actuators and other attached main steam components

- Retuned the steam system 13

How Does the ASB Work?

The addition of the ASB increases the effective length of the ERV/SV standpipe, thereby decreasing the frequency of the acoustic standing wave. It is similar to a muffler, the ASB tunes the steam flow to reduce vibrations in the piping.

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Acoustic Side Branch Mod ASBs Main Steam Safety Valve Electromatic Relief Valve 15

Unit 2 Startup Testing RESULTS:

• EPU Flow Induced Vibration (FIV)

Reduced to ~ 50% Original Licensed Thermal Power Levels.

- Meaning: today steam piping vibration levels at full-EPU power is approximately 50% than when the plant was first put in to commercial operation in 1972.

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Typical Accelerometer Data Results Q2R18 Accelerometer Trends Target Rock Inlet Flange - X 0.4 3A Target Rock Inlet Flange X1 Historical (pre-ASB) EPU Value 0.35 Historical (pre-ASB) OLTP Value 3A Target Rock Inlet Flange X2 3A Target Rock Historical - X 0.3 0.25 Acceleration, grms 0.2 Last May w/o ASBs 0.15 With ASBs 0.1 0.05 0

0 500 1000 1500 2000 2500 3000 Core Thermal Power, MWt 17

Conclusions ASBs Work!

• Main Steam Line (MSL) vibrations are reduced

• The ASB modification effectiveness has been confirmed. This adds significant safety margin and substantially increased vibration tolerance to the steam dryer structural integrity and other main steam line components.

• Both units can operate safely and reliably at EPU power levels.

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Radiation Exposure Efforts 19

Station Has Taken Aggressive Actions to Reduce Radiation Exposure

• Chemical decontamination of reactor piping on both units

• Replacement of turbine blades which contained high sources of Cobalt 60

• Installed permanent lead shielding in several high radiation areas of the plant

• Improved worker training / increased awareness through individual dose goals 20

U2 Outage Dose Reduction Trend 600 rem Red Red line line represents represents 150 150 rem rem -- our our path path 500 rem to to full full INPO INPO points points 486.0 and and industry industry best best 400 rem 436.3 dose dose performance performance Dose (person-rem) 336.2 300 rem Industry Best 200 rem 190.0 162.0 100 rem 0 rem Q2R16 Q2R17 Q2R18 Q2R18 Q2R19 projected (2002) (2004) (2006) minus ASB / Dryer (2008) 21

Where Are We Going INPO Collective Radiation Exposure Point Performance 10 points 10.0 9.7 9 points Industry Best 8 points 7 points Red Red line line represents represents 6 points 150 150 rem rem -- our our path path 6.2 to to full full INPO INPO points points 5 points and and industry industry best best dose dose performance performance 4 points 3 points 2 points 1 points 0.0 0.0 0 points Current 2007 2008 2009 Full Points 22

Questions?

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