OAGI0001534_00003

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ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 | 05000286 Exhibit #: Identified: Admitted: Withdrawn: Rejected: Stricken:

Other:

NYS000377-00-BD01 10/15/201210/15/2012

NYS000377 Submitted: June 19, 2012

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Steam Generator 'rube Operationai Experience [ Indign Point 2 EVe,llt ! Nude"f Rpactors I NRC Home Palle]

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Early; cOID_mercia1 nuclear power plant steam generator tubes were formed from Alloy 600, a cOITosion-resista.!lt pjgh-nickel alloy- 'Early supplies of the Ailoy 600 tubes were provided in a null-anneal condition. Most of the steam generator tubes which have required plugging over the years have been IT'ill-annef'lled Alloy 600 tubes. Infonnation on the operational experience with Alloy 600 tubes can be found in t,l-je follo'.'!ing NRC Infonnation Notices:

• IN 98-27 ""("am Generator Tube End Cracking"

• L-r...T 97-88, "Experiences During Rece·n! ·"team Generator Tnsoections"

• IN 97·49. "B&W Once-ThrQugh Steam Generator Tube Inspection Findings"

• IN 97-26. "negl'l'rtation if! Small.Radius V·Bend Regions oLSteam Generator Tubes"

eo ll'~ St,6-38, "Results of Steam Generator Tube Examina.tinn~ " .. n~ 94-62_ "OtJt!raiional EXDer1enCe on Steaifi. .. Ocnerator Tube Leaks and Tube Ruptures'!

• ll'1 90-49. lIStress Corrosion ("r:.c.king in PWR Steam Generator Tubes':

Subsequently ~ steam geTIerator tube man.ufacturers deterrnined that by the.rrn.a11y treating the AJloy 600 material for later tubes, the corrosion resistance of the tubes was improved Industry experience with thermally tieated Alloy 600 stea.'tl generator tubes suggests that these tubes are more resistant to in-service cracrJng than nlil1-annealed Alloy 600 tubes. A few indications of degradation in thermally treat.ed Alloy 600 tubes have been reported, however, a.T1d one is discussed in IN 97-26, listed above.

f-.JO\V, most steam generator tubes for Hew steam generators are being fabricated from thermally treatec Alloy 690, rul alloy \vith a higher a...'1l0unt of cp..rowiurn and red\lCed amount of nickeL Alloy 690 is considert:d to be very resistant to t..'1e types of degrad:ltion experi.enced by the ..A.lloy 600 lllhes. At this time, the NRC staff js noi aware of any primary br secondary side cracking in P-J1ay 690 tubing.

Some WoeS have also been plugged due to fretting and denting, degradation mechanisms due to the design of the support plates and antivibration bars and the presence ofloose pa."ts, rather than tIle tubing material .

In the 20 years preceding the failure at Indian Point 2 on February 15,2000, there had been seven steam generator tube ruptures in commercial nuclear power plants, all in tubes fabricated from rrJll-annealed Alloy 600. The last tube rupture occurred in 1993 at Palo Verde. j TJnit 2 ~ It is considered a tube rupture rather ihan mereiy tube leakage when tube leakage of reactor coolant exceeds the- ma..lce.up capacity. SeL Table 1 for information about the seven tube ruptures.

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Figure 1. Example steam generator tube rupture at lVf,,(;niTp Unit 1

There are other cases where defects have grown through the thickness of the tube waii, and caused the tube to leak. In these cases, either the plant was shut down due to the tube leakage, or the through-wall defect was netected as a result of the tube insoection during a plant outage. "_,. .. n... _. _ ~ ...... __ ._.. -"'--_ ___ _

Table 1. Steo!lo"1 Generator Tube Ruptures (from NUREGfCR .. 6365)

1;:;0550<5 and II

rase pa.~.s weari:'~h:~,;~'l~;~~g :1 :1 ~ ,\

liLoose parts !wear, fretting

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ICQntrihuting Factors I

- Slightly above t..~e ILarge sludge pile, ~ ! tube-sheet, outer row ineffective cleaning ! 'on the hot Ie. side I i !Top ofU~be~{Hn - ~'d~ioYh <1;':;'1"<1,,1" ... ~~iI"--"-=-"""il !Row 1, Column 7 11~~;:ii;a~i~~-;a~~;d bv 11

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II 1Tube bundle outer ~surface, 76 mm labove the tubesheet Ion the hot leg side, iRow 4, Column 1

lIinward movement of the II hegs due to support plate II deformation II ~sludge lancing ,equipment left in the

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127 mm above the Loose parts (baffle plate ~tubesheet on the hot ,debris) left in the steam ~Ieg side, Row 42, generator, wear of ,IColumn 55 (third peripheral mbes, fretting II !Irow in from the, .of inner tubes J'I bunale periphery) .I

ilHigh-cycle ,360 circumferential ITop of the 7.th upper IHigh-cycle vibration, ~ ~fatigue !break ube support plate on Ide~tin?, la~k ~f II a ~ Ithe cold leg side, ~antl-VIDraUOn oar II !.......t., .. , . _, .iI<.ow 9, Column 51 .llsuppon..... .,. , .. .11 ~Outer diameter 1195 mm long axial crack ~711 mm above the ~Long shallow groove, II ~stress corrosion ~in a 645 mm long Itubesheet at the ipossibly a contaminant i ~cracking ~groove, 9.5 mm wide atllower tube support II ~ ~ ithe maxImum pomt Ilplate ~n th~ :OIa leg ~ I ~ ~ ~~a~, KO';: 10, II I , , ,! . ~LOlumn .:5 , ' I .. ' ... : ~ ~Outer dlarne~er !165 mm long axIal , jFreespan ~eg:~~_ J!Ube-to-tu~e c:~vlce II ~stress. corrosion ~fis~mou~ opem~~ 10 a I~~ee.n me UI:SH. ano ~~nna~ont Dn~gmg II Icracking F5U!"'" long ax"li IU~t1 moe suppon ~(jepo .. ts, causUc ! g ~craCK IIsti'uctures on the hot Iisecondarj water II II J g. ....... ~ .. _ •. ,

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:am Generator Tube Operational Experience

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