ML040980524

March 11, 2004 - RIC 2004 Presentation - T11 - Christopher Crane - Emergent Technical Topics

ML040980524
Person / Time
Site:	Dresden, Byron, Three Mile Island, Braidwood, Clinton, Quad Cities, LaSalle
Issue date:	03/11/2004
From:	Crane C Exelon Nuclear
To:	Office of Nuclear Reactor Regulation
References
RIC 2004
Download: ML040980524 (9)

Text

Exelon Experience with Power Uprates RIC 2004 Emergent Technical Issues Session T-11 Chris Crane President and Chief Nuclear Officer Exelon Nuclear March 11, 2004

Power Uprates The majority of Exelon power uprates are complete with 887 MWe added to fleet capacity with 76 MWe scheduled in 2006 Gross MW 76 480 293 963 114 2000 2001 2002 2003-2005 2006 Annual Increm ent 2

Exelon Power Uprate Details LaSalle Unit 1 120 LaSalle Unit 2 Braidwood Unit 1 100 Braidwood Unit 2 80 Byron Unit 1 Byron Unit 2 We Gained 60 Dresden Unit 2 TMI Unit 1 40 Braidwood Unit 2 20 Byron Unit 1 Clinton Unit 1 0 Dresden Unit 3 2000 2001 2002 2006 Quad Cities Unit 1 Year of Uprate Quad Cities Unit 2 Clinton Unit 1 3

Exelon Results of Power Uprates

• Majority of power uprates successful with the following exceptions:

- Quad Cities Unit 1 and 2 experienced Dryer structural integrity and steam line component (Electromatic Relief Valve (ERV)) vibration issues

- Dresden Unit 2 and 3 both experienced varying degrees of Dryer cracking and both units had isokinetic probes dislodged and migrated to the feedwater sparger 4

Root Causes of Uprate Issues

• Steam Dryer Failures High cycle fatigue due to increased amplitude of flow induced and acoustic loading from increased main steam line velocities

• Main Steam Line Component (ERV Actuators)

Accelerated aging due to EPU related increase in main steam line vibration levels

• Feedwater Isokinetic Sample Probe Failures Flow induced vibration due to increase in feedwater flow 5

Conclusion

• Quad Cities and Dresden are the exceptions to successful power uprates

• Lessons learned

- Refrain from fast track temptation on power uprates

- Implement a proactive vibration monitoring plan

- Evaluate steam flow effects on steam dryer and other steam flow sensitive components

- Evaluate pre-existing operational margin limitations against the uprate expected effects 6

Current Industry Response

• Active dialogue with NRC via Issues Program Groups and Industry Executive Leadership

- BWR Owners Group

- BWR VIP

• Issues Programs active in assessing generic issues

• Generic Insights will be appropriately factored into Issues Programs and NEI Materials Initiative 7

BWR Future Activity

• For BWR Fleet in U.S., active assessment by executive leadership of need for generic versus plant specific solutions. Working with GE at the executive level

• Near Term determination of technology and design review needs to bound structural and acoustic design requirements for some plant types 8

Overall Industry Focus

• Licensees and Issues Programs recognize the need to determine safety significance of any emergent issues

• Active engagement with the NRC will serve the needs of all stakeholders

• New design and technology insights may emerge from IP scope and near term work 9