ML12335A412
| ML12335A412 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 12/22/2011 |
| From: | Hausler R Corro-Consulta |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 21600, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
| Download: ML12335A412 (2) | |
Text
United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of:
Entergy Nuclear Operations, Inc.
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #:
Identified:
Admitted:
Withdrawn:
Rejected:
Stricken:
Other:
RIV000019-00-BD01 10/15/2012 10/15/2012 RIV000019 Submitted: December 22, 2011 EXCERPT c,.",tJ"oR REGlJ<..q"
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Tel: 9729628287 CORRO-CONSUl TA Rudolf H. Hausler 8081 Diane Drive Kaufman, TX 75142 Mobile 9128245871 Fax: 9729323947 Flow Assisted CorrosioQ (F AC) and Flow Induced Localized Corro.lop:
Comparison and Discussion Summary The computer model Checworks, used to manage aging of hot high pressure water and steam carbon steel lines was designed for Flow Assisted Corrosion (FAC) phenomena. Erosion Coo:osion, Impingement and Cavitation are expressly excluded as unrelated to F AC. It is shown that the latter three corrosion phenomena are extensions of F AC as the local flow intensity due to turbulence increases. The transition from one to the others is continuous and difficult to identify. F AC therefore is only one manifestation of Flow Induced Localized Corrosion (FILC).
The localized corrosion rate under the umb(ella ofF AC varies, per definition, almost linearly with fluid velocity; however, this linear relationship transitions
. into an exponential one as the local turbulence becomes such that erosional features become manifest. Whether such transition actually occurs following a power upgrade (PU) must be determined experimentally. It cannot be estimated from within Cbecworks.
It has been stated that "the algorithms used to predict the F AC wear rate are based on extensive laboratory and plant data. This assures that the F AC wear rates predicted by Checworks are accurate." This accuracy is said to be within +/- 50%.
However, this statement is based On an erroneous intexpretation of the graphic repl'esentation of predicted vs. measured wear. Actually, the accuracy is within a factor 2. The measured wear ranges from twice the predicted to half the prediction.
Partial review of the result from the pipe inspections using Cbecworks in 2003 and 2006 shows significant unexplained discrepancies.
I.
Introduction The Wrect testimony by Dr. Jeffrey S. Horowitz 8I)d Dr. James C. Fitzpatrickl ) with*
regards to NEC Contention 4 - Flow Accelerated Corrosion bas raised a numbex of questions, which are being discussed below:
I) Joint Declaration of Jeffrey S. Horowi~ and James C. Fitzpatrick on N,EC Contention 4 - Flow-AcCelerated CorrOllioll, May 12, 2008.
61212008 loft2 RHH Rebuttal
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measured ones is derived from a representation. of the data as shown in Figure 3 below. It is true that when the measured wear data are plotted against the predict~
ones most of the data points lie between two lines that are plotted +/- 50% off the 45 degree equivalency lines. This inte:t:pX"etation is totally misleading and scientific!ally
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First, one sees that there is no correlation between the predictions and the actual measw:ements. Second, one also sees that measurements which we are made to believe are within 50% of the predicted value are really twice as large or larger;.
similarly, on the other side one sees that 'measured values are half or less of the predicted ones, again a.factor of2 different.
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Conclusion:==
Tbe accuracy of Chec.works is ** ch that the measured values an within a factor of +/- two (+/.., 1] of the predicted yalue8 rather thall +/- 5... 10 as dabaeel.
A factor-ef-twg difference between measured an(predicted corrosion (or cOITosion rate} can. be quite significant with respect to selecting a particular item (line) for inspection during a given refueling outage. Indeed the report of the "EPRI Checworks Wear Rate Analysis Results for Cycle 22B"lS) shows that the time predicted to reach the critical minimum wall thickness in a majority of cases is many years negative.
1his m.eans that the item should have failed a long time ago. Sinrilarly, the:remaining time to failure may be grossly overestimated. But one will never know unless the proper inspections are perfonned and the com~uter model recalibrated, a process Dr.
Horowitz and Entergy seem to find irrelevant. 6)
Examination of the data from March 2003 (RFO 23) showed average and measured corrosion rates of the order of2S and 21 mpy, respectively, for-the outlet <LP-l~lA" on line OOl-16-FDW-Ol. In May of 2006 these same rates have come down to 7.524 and 5.712 mpy~ respectively. 11) It is hard to see how this could have happened. There is in the program something called "Line Correction Factor." This factor has been de:fu:ted by Dr. Horowitz as the relationship between predicted and measured corrosion rate (see below18>>. However in 2003 this factor was 0.649 and by 2006 it had become 0.175. It is amazing to observe that fudge factors axe built into the program. which
)6) Joint >>eclaratiOD of JefD"ey S. Horowitz and James C. Fitzplltrick on NEe Contention 4-Flow-:-
Ac.c::elerateci Corrosion: A 34.
I) Exhibit E-4-30.
II) HOROWITZ'S 1"ESTIMONY STATES THE. fOLLO'WlNG ABOUT TIlE ABOVE-MENTIONED
"'CORRECllON FACTOR" AT A28: "A Pass 2 Analys.is cwnpares the measwed jnspec:tion results to the caJ~1ated wear raIm and adjum the F AC rate calculations to actount for the inspectioD results. The propao.1. does, this by comparing the predicted lUQOunt of deeradation with the measured degradati~ ~
each oftbe ins,pected components. Using statistical methods, a correctionfactor is detemliDed WblCh 15 applied to aU components in a given pipe line - whether or not they were inspected."
6/212008 8 ofJl
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