ML12088A387

Entergy Pre-Filed Hearing Exhibit ENT000040, Fatigue in Operating Nuclear Power Plants Components After 60 Years

ML12088A387
Person / Time
Site:	Indian Point
Issue date:	02/21/2008
From:	Gosselin S Battelle Memorial Institute, Pacific Northwest National Laboratory
To:	Atomic Safety and Licensing Board Panel
SECY RAS
Shared Package
ML12088A381	List: ML12088A382 ML12088A383 ML12088A387 ML12088A389 ML12088A390 ML12088A391 ML12088A394 ML12088A395 ML12088A398 ML12088A400 ML12088A401 ML12088A402 ML12088A404 ML12088A405
References
RAS 22101, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01
Download: ML12088A387 (9)

Text

ENT000040 Submitted: March 28, 2012 Fatigue in Operating Nuclear Power Plants Components after 60 years Steve Gosselin Pacific Northwest National Laboratory 509-375-4463 stephen.gosselin@pnl.gov Joint U.S. Nuclear Regulatory Commission (NRC) and U.S.

Department of Energy (DOE)

Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues Bethesda, MD, February 19-21, 2008

Summary Service Experience Component Fatigue Qualification and Serviceability Challenges and Directions for the Future Questions and Discussion Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 2

U.S. Failures by Degradation Mechanisms Flow Accelerated Corrosion 32.5%

Stress Corrosion Cracking 21.4%

Vibration Fatigue (incl. Fretting) 18.7%

Corrosion (Crevice, MIC, Pitting) 14.8%

Design & Construction 6.5%

Thermal Fatigue 1.5%

10,000 reactor years of service Erosion-Cavitation 1.4% experience with commercial Over-stressed / Over-pressurized 0.8%

LWR nuclear power plant piping systems Water Hammer 0.8%

Human Error 0.7%

Unreported 0.4%

5164 reported failures Corrosion Fatigue 0.3%

Severe Weather (Freezing) 0.1%

0% 5% 10% 15% 20% 25% 30% 35%

Source: PIPExp Database Data from 1970-2007 Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 3

Fatigue Failure Experiance Fatigue accounts for 21% of all reported failures in domestic operating NPPs Vibration Fatigue f 90% of the reported fatigue failures f Most all in small bore socket weld connections Thermal Fatigue f 2% of all reported failures y Thermal Stratification y Turbulent Penetration Effects y Hot/Cold Mixing Generally the occurrence of these failures has not significantly changes in the last 35 years Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 4

Vibration Fatigue Socket Weld Failures Socket Weld Failures (601 Records as of 12/31/2007) 70 60 No. Socket Weld Failures 50 40 30 20 10 0

19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 20 20 20 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 Source: PIPExp Database Data from 1970-2007 Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 5

Thermal Fatigue Failures 14 BWR (77 Events) 12 PWR (101 Events)

LWGR+PHWR (8 Events)

Number of Thermal Fatigue Failures All Plant Types (186 Records) 10 8

6 4

2 0

19 19 19 19 19 19 1970 72 74 76 78 80 19 19 19 19 19 1982 84 86 88 90 92 94 19 19 20 20 20 20 96 98 00 02 04 06 Source: PIPExp Database Data from 1970-2007 Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 6

Fatigue Qualification and Serviceability Component design and operation will be limited to prevent fatigue crack initiation Component is designed and operated in a manner that will tolerate fatigue accumulation and crack growth without reducing the structural integrity below acceptable limits - 'damage tolerant Component design and operation will be limited so that component failure probability/frequency is within established component reliability goals.

Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 7

Challenges and Directions for the Future Environmental fatigue effects make it more difficult to rely base serviceability on traditional ASME Class 1 analyses Synergistic effects of other mechanisms (e.g., corrosion, cast stainless steel thermal embrittlement, etc.)

Advanced reliability models consider all relevant design, operation and maintenance practices, surveillances, etc, so that ensure that fatigue sensitive components will continue to operate with established reliability goals Expand application of damage tolerant and PFM methods for component fatigue qualification and fitness for continued service beyond 60 years.

f Component weld fabrication flaw size and density distributions f Uncertainties in material properties, weld residual stresses, and NDE detection and flaw characterization capabilities Joint U.S. NRC -DOE Workshop on U.S. Nuclear Power Plant Life Extension Research and Development Issues, Bethesda, MD, February 19-21, 2008 Slide 8

Questions and Discussions