ULNRC-05423, Responses to Requests for Additional Information Regarding Requests for Relief from ASME Section XI Code Examination Requirements, RRs ISI-34, ISI-37, ISI-38, and ISI-40

Responses to Requests for Additional Information Regarding Requests for Relief from ASME Section XI Code Examination Requirements, RRs ISI-34, ISI-37, ISI-38, and ISI-40

ML072390353
Person / Time
Site:	Callaway
Issue date:	06/29/2007
From:	Graessle L AmerenUE, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Donohew J N, NRR/DLPM,415-1307
References
TAC MD3433, TAC MD3435, TAC MD3436, ULNRC-05423
Download: ML072390353 (23)

Text

Union Electric PO Box 620 Callawar Plant Fulton, MO 65~251

.lune 29. 2007 UJ.S. Nuclear Regulatory Commission Attn: Documlent Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Ladies and Gentlemen: ULNRC-05423 DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT I wAmeren UNION ELECTRIC CO.

RESPONSES TO REQUESTS FOR ADI)ITIONAL INFORMATION Uie REGARDING REQUESTS FOR RELIEF FROM ASME SECTION Xi CODE EXAMINATION REQUIREMENTS (INCLUDING WITHDRAWAL OF RELIEF REOUEST 1S1-37)

Reference 1: AmerenUE Letter ULNRC-05 183, "Requests Ior Relief from ASME Section XI Code Inservice Examination Requirements." dated October 25, 2006 By letter dated October 25, 2006 (Reference I) and pursuant to 10 CFR 50.55a(a)(3), AmnerenUE (Union Electric Company) submitted several requests for relief from applicable examination requirements of Section XI ol1 the American Society of Mechanical Engineers (ASME) Code. The relief requests are for the second 10-year interval of the Inservice Inspection (ISI) Program at the Callaway plant. which ended on December 18, 2005. As noted in the letter, the Code Edition(s) and Addenda applicable to Callaway's second 10-year ISI interval are ASME Section XI, -'Rules for lnservice Inspection of Nuclear Power Plant Components.-' 1989 Edition, with no Addenda (and 1995 Edition with 1996 Addenda, as applicable).

The relief requests submitted via AmerenUE's October 26. 2006 letter were identified as ISI-34. -35, -36. -37. -38. -39. -40, and -41. Half of these relief requests have now been approved by the NRC. The relief requests that have not yet been approved and are still under review by the NRC are ISI-34, ISI-37, ISI-38 and ISI-40. From its ongoing review of these relief requests. the NRC staff has transmitted several requests for additional information (RAIs) for which responses firom AmerenUE are needed in order to support completion of the NRC's review.

Accordingly, this letter provides AmerenUE's responses to the NRC's RAIs. The RAI responses are provided as attachments such that Attachment I provides the response to the RAI received for ISI-34, Attachment 2 provides the response to the RAI received in regard to both ISI-37 and ISI-38. and Attachment 3 provides the response to the RAI received for 1SI-40. Within each attachment.

asubsidiary otAmoten Corporation

ULNRC-05423 June 29. 2007 Page 2 each of the individual questions/requests contained in the associated RAI is stated and immediately fIollowed with AmerenUE's response. Text from the NRC's RIl(s) is-shown in italics.

Regarding Relief Request ISI-37. it should be noted that AmerenUE is withdrawing this particular request. The determination to withdraw ISI-37 was made in response to one ol'the NRC's RAI questions pertaining to this request, as explained further in Attachment 2.

AmerenUE appreciates the NRC staffs continued review o1 the remaining relief requests. For any questions regarding the attached infomration. please contact me at 573-676-8129 or Scott A. Maglio at 573-676-8719.

Sincerely, Iý Luke 1-1.Graesslc M~mager - Regulatory Affairs TBE/jdg Attachments

ULNRC-05423 June 29, 2007 Page 3 cc: Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 61 1 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Scnior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohcw (2 copies)

Licensing Project Manager. Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-7D1 Washington, DC 20555-2738 Missouri Public Serice Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360

ULNRC-05423 June 29, 2007 Page 4 bcc: C. D. Naslund L. M. Belsky (NSRB)

A. C. Heflin K. A. Mills T. E. I-Hernnann T. B. Elwood L. H. Graessle G. A. Forster S. A. Maglio M. G. Hoehn 11 D. M. Stepanovic A 160.0761 G. A. Hughes D. E. Shafer S. L. Gallagher (I 00)

Certrec Corporation 4200 South Hulen. Suite 422 Fort Worth, TX 76109 (Certrecreceives ALL attachments as long as they are non-safeguards und maj, be publicly disclosed.)

Send to the followVing without attachments:

Ms. Diane M. Hooper Mr. Dennis Buschbaum Supervisor, Licensing TXU Power WCNOC Comanche Peak SES P.O. Box 411 P.O. Box 1002 Burlington, KS 66839 Glen Rose. TX 76043 Mr. Scott Bauer Mr. Stan Ketelsen Regulatory Affairs Manager, Regulatory Services Palo Verde NGS Pacific Gas & Electric P.O. Box 52034, Mail Stop 104/5/536 Mail Station 7636 P.O. Box 56 Phoenix. AZ 85072-2034 Avila Beach, CA 93424 Mr. Scott Head Mr. John O'Neill Supervisor. Licensing Pillsbury Winthrop Shaw Pittman LLP South Texas Project NOC 2300 N. Street N.W.

Mail Code N5014 Washington, DC 20037 P.O. Box 289 Wadsworth, TX 77483

Attachment I to ULNRC-05423 REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST ISI-34

Attachment I to ULNRC-05423 REQU EST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST ISI-34 In the submittal dated October 25, 2006, Union Electric Company (the licensee) requestedrelief from cer'tain requirentents containedin the licensee irisk-informed inservice inspection (1,V1) progranm iihich was deveopecd according to Electric Power Research Institute (EPRI) Topical Report (TR) TR- 11265 7, Revision B-A, "Revised Risk-Informed Inscrvice Inspection Procedhure." Specffically, the licensee requested relieffi'om the inservice inspection 100%

volumetirc coverage requirementfi)r weld regions. The licensee's ReliefRequest (RR) ISI-34 is for the secomil 10-year inseirvice inspection interval.

Paragraph50.55a(gJ(5)(ii) of Title 10 of'the Code of FederalRegulations (10 CFR) states that when licensees deItermine that conformance with certain code rLequirements is impracticalat theirfacility, they shall submit information to support this determination. The Nuclear Regulatory Commission (NRC) will evaluate such requests based on impracticality,and may impose alternatives,given due considerationto public sqaty and the bunrden imposed on the licen7see.

To continue the reiview (f'RR 1S1-34, the NRC staff requests the fillowiing additional informnation.

1. In the licensee s letter dated February 16, 2001, Section 3.5.2, "P'rogram Relief Request, " it states, "At this time, all the RI-ISI examination locations that have been selected provide greaterthan 90% coverage. " In the licensee's letter datted October 25, 2006, Section 5, "Burden Caused by Compliance. "it states, "It was known at the time of selection that a conilict existedl between the requiredweld vohtmne and ttltrasonic inspection quclificution. Explain the apparentconflict between these two statements.

Response

The statement in the October 25, 2006 letter was poorly worded. As stated in the February 16. 2001 letter, an attempt was made to make selections based upon coverage.

H-lowever. choosing locations susceptible to active degradation mechanisms was deemed more important than choosing locations that may have resulted in better coverage but which had no active degradation mechanism. For the February 16. 2001 letter. it would have been better to state. "It was known at the time of selection that a potential conflict existed between the required weld volume and ultrasonic inspection qualification (PDI rules)." AmcrenUE chose the noted locations because active degradation mechanisms were identified during the evaluation process. AmerenUE therefbre believes that the selected locations are the right ones to examine.

Page I of 5

Attachment I to ULNRC-05423

2. The letter dated October 25, 2006, reduces the examination coverage for welds in the licensee's RI-ISl program. Discuss hovi' the licensee 's program will satisfy the minimuni coverage criteriain the weld populationthat contributes to the percentage of the piping weld popudationreferenced in TR- 112657.

Response

As stated in the October 25, 2006 letter, "Using the degradation mechanism insight of Code Case N-7l1 and its associated white paper, Callaway Plant could take credit for examining 100% of the area of interest for the subject welds." The insights of Code Case N-71 1 were developed in the years following issuance and approval of TR-1 12657. The intent of the request for relief (ISI-34) was to incorporate those insights, ensuring that appropriate locations remain selected (i.e., welds with active degradation mechanisms) and that for each of the subject welds the appropriate required examination volume for the degradation mechanism is utilized and achieved as shown on figures "Coverage BI" and "Coverage B2."

3. The letter dated October 25, 2006 briefly listed the limitationsfor less than 100%

coverage in the table titled "Descriptionof Coverage Limitations." However, the table pro 'ided insufficient inibrmnationto demonstrate impracticality. For each subject weld, i)roivide a cross- sectional sketch identifying the material (carbon steel, cast or wrought stainless steel, cast or wrought nickel based alloys) in the iveldi region, ide'ntifying the wall thickness at the weld, and showing the inteit'rence location.

Response

All welds are stainless steel components to wrought stainless steel pipe welds.

The following sketches (shown on the next page), which are from the UT reports. are typical for the component welds in ISI-34 Page 2 of 5

Attachment I to ULNRC-05423

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4. The letter dated October 25, 2006, states that ISI-34 examinations were performed during the spring of'2004 refiueling outage (RF) 13. The ultrasonictesting (UT) techniquesfr pipe examination pCr/.br1ned in 2004 must be qualified to the requirements qfSection Xl, Appendix VIII. For the pipe configturations common in the power plant, the Electric Power Research InstitulePerfbrmance DemonstrationI7itiative (PDI)has representative nockups that are used./br Section XI, Appendix VIII performance Page 3 of 5

Attachment I to ULNRC-05423 demonstrations. For pipe configurationsnout in the PDIprogram,the licensee must satisfy Section X1, Appendix VIII requirementsin-house.

Discuss the differences between the mockup and weld configurationsin the PDI program and the mockups and weld configurationsneededfor the subject welds. Discuss the availabilityof site-specific mockups of the subject welds and any demonstrationsto establish the efectivieness ofprocedures and personnel qualified through the PD1 program or site-specific program.

Response

The subject examinations were performed in accordance with the PDI program for Supplement 2. Single-sided access austenitic piping welds are included in the performance demonstration test samples for these configurations: therefore. site-specific mock-ups are not applicable.

5. The regulation 10 CFR 50.55o(g)(5)(iii) is predicatedon the licensee's determinationof impracticality. Discuss other non-destructive examination (NDE) methods and ultrasonic test (UT) techniques thMat were evaluated to increase the examination coverage, such as phased arrayon taperedsutjaces, weld crown7 removal to increase scanning, digital radiography,state-of-the-art volumetric examinations, etc. Include a summary of the demonstration results, if any.

Response

Callaway Plant is committed to utilizing the best available technology for performing ISI NDE. However, the welds in question are on piping 6 inches or less in diameter. As such. there is no qualified technique for performing UT examinations firom the inside diameter. including phased array, etc. The condition of the weld crown was blended with an ISI prep, as required by the Callaway ISI Program for all ISI piping welds.

Radiography was perlbrmed prior to service as required by ASME Section I111 Construction Code.

The examinations under consideration in ISI-34 were examined in accordance with PDI-UT-2. PDI-UT-2 Step 1.8 states, "This procedure is not qualified for... detection or length sizing of circumferentially oriented flaw indications when only single-sided access is available and the flaw is located on the far side of the weld; however, guidance is provided. The techniques identified in this procedure have been demonstrated to be representative of the 'best effort' technology fbr single-side detection of far-side defects parallel to the weld." Therefore, the examinations performed at Callaway were, in fact, based upon the best demonstrated technology available.

Page 4 of 5

Attachment I to ULNRC-05423

6. Pa,ge 4-13 of'EPRI TR TR-112657 provides a disculssion om limited exaimnations of auslenitic-to-awtdenitic HICIh/s. The description of the wehl c'figuirationis simil/tr to wLhld cojiigturalionsused/fbr ASME Code Section XI, Aplpendix I'1 S11/.)p/Spl'nit 10 quat/[ficaliois perfornedfrom the anstenitic side of the re Ud. Discuss tipici/)f)licabilityof usinkg Suqpplement 10 qiiali/iedprocedhuresandpersowiV c in liell of Suqpplement 2 qualified procechures andpersonnel to increase weld coverage.

Response

The wvelds in question are not dissimilar metal welds: therefore. Supplement 10.

"Qualification Requirements for Dissimilar Metal Piping Welds," was not applicable for these welds and was not used. Had AmerenUE chosen to use Supplement 10 for these welds at Callaway. it would have required submission of a request flor relief in advance.

However. per discussion with EPRI personnel. because of the conligurations involved (small bore piping to component welds) no increase in coverage could have been claimed. Therefore. ISI-34 would still have been required and the reliel" needed to use Supplement 10 instead ol' Supplement 2 as required would have caused unnecessary burden and cost, both to the station and the regulator.

The industry efforts to achieve a qualified single-sided access examination per Supplement 2 are being coordinated through PDI and EPRI. AmerenUE supports these effcorts, both financially and by participating in the PDI program. This is the appropriate research forum1, as industry experts are actively engaged in advancing the technology of ultrasonic examinationls.

7. Discuss (1) the achievable excumination coveragefor (upstreuclcmdoiislwstreanm) welds C(IjaCCmI to Ihe subject welts and (2) the applicabilityv of'suqpp/enenting the subject weld CxamninattionXs with atdjacent wield examinations.

Response

The upstream and downstream piping welds have been reviewcd. Most have similar limitations, do not have appropriate degradation mechanisms, or already have been selected fbr examination. These welds cannot be used as substitutes or to increase examination coverage fbr the welds listed in ISI-34.

Page 5 of 5

Attaclmient 2 to ULNRC-05423 REQUEST FOR ADDITIONAL INFORNIATION REGARDING RELIEF REQUESTS ISI-37 AND ISI-38

Attachment 2 to ULNRC-05423 REQUEST FOR INFORMATION REGARDING RELIEF REOUESTS ISI-37 AND ISI-38 Relief Rcquests 181-3 7 and 1S1-38 wvere subinitedby Union Electric Company (11he licensee) in its applicationdated October 25, 2006. The Relief Requests are for the second 10 -year inservice inspection (1.S1) interval. 1989 Edition i'ith no Addenda of American Society of Mechanical Engineers (ASME) Code. Section Xl as the ASME Code of record.

In its letter dated October 25, 2006, the licensee requestedrelieffirom the ASME Code.

Section XL, requirements for reactorpressure vessel (RP V) lower shell-to-lower head circumni/rentialweld 2-R V- 101-141 and fir RP V inlet saft end-to-elbow weldr 2-BB-OI-F]02, 2-13B-O1-F202, and 2-BB-01-F302, in RR 1,81-37 and RR ISI-38 respectively. Six questions/reqifestshave been identifiedfr'oin the NRCs review of 1S-37 and IS1-38. (Question 5 is a two-part qzuestion.)

Relief Request ISI-37 For RPPV lover shell-to-lower head circunifrrentialweld 2-R V- 101-141 the ASME Code,Section XI. Table IWB-2500-1, Category B-A, Item B. 21 specifically states that a volumetric examination of essentially 100% shall be performed on the accessible length of all welds on the RP V lower shell to lower head circi.,mforentialweld.

I According to the WVestDyne hIternational RP V Results Sutmininarj reportfor the subject weld provided by the licensee in its letter dated October 25, 2006. it was noted that the licensee obtained approximately 77.3 percent coverage of the examination volume; however, the licensee did not specij, f the 77.3 percent coverage of the examination voltme wias ofthe accessible weld length or total iveld length. Therefore.fior this spcific case, the licensee may want to consider reassessingthe ASME Code requirements in that if the licensee act'ually obtained essentially 100% of the accessible weld length relief'may not be required

Response

AmerenUE understands the point made by this question from the NRC and concurs with its conclusion. 100% of the accessible weld length was obtained.

The 77.3% refers to the total weld length. Historically. AmerenUE has tended to conservatively request relief to assure complete compliance with Code requirements at Callaway. In this case, it was not clear what was meant by the Code terminology, so relief was requested. In light of this clarification.,

AmerenUE requests withdrawal of RR ISI-37. For completeness, Question 2 is still answered as follows.

Page I of 6

Attachment 2 to ULNRC-05423

2. In the/i report it ir05s cdlso notedl th/a (hdringthe iitrcixonic (UW) examinution one A SME Code-c/lob oahle indication was identified. 1/'relief is required,provide a briefdiscussion oft/he dislosition of the indicationfimi uhnring the UT examinatioi. In addfition, dfid the incdication extendl hito the unin.pectuble ivohlane?

Response

The indication was allowable in accordance with Table IWB-3510-1. The indication did not extend into the uninspectable volume.

Relief Request ISi-38 For the RPV inlet sqfe end-to-/howii'elds 2-BB-0O-FI02, 2-BB-01-F202, and 2-BB-0I-F302. the ASME Code, Section Al, Table IWB-2500-1, Categomy B-J, Item:

B9. 11 requires volumetric anml su.'face exaimnition of essentially 100% ofthe subject weld length.

1. According to the IVestDyne InternationalRP V Results Summar, r-eportf./ri'weld 2-BB-01-F102. the licensee obtainedcmpproximateli' 50% coverage of the exatuination vol/uiee. hi the report it was noted ihat (hilring the ullrasonic (U7) examination six ASME (..'ode-adlowable indications iwicre identfied. Provide ai briiefdiscussionqf the lSisitioNm Qf tlhse six inlicattions identified during the UT ufxamination. In a(hlition, did an1)' of the indicatiomis extend into the uninspectahle

Response

During the examination of 2-BB-0 1-F 102. 100% of the volume was examined in the axial direction (looking for circumferential indications). The PDI qualification that the vendor was qualificd to had the following statement of limitation: "This procedure/candidate is not qualified to dctcct axial flaws in either Supplement 2 or 10 welds which are not either ground smooth or machincd smooth with no exposcd root or counterbore.'" For 2-B13-01-F102, this condition was encountered. This resulted in no coverage under the rules of PDI Ior circumferential scans. This resulted in an aggregate coverage of 50% (100% from the axial direction,'0% from the circumferential direction). As such. the indication did not run into the uninspectable volume. See AmerenUE's response to Question 5 below for a discussion of other tcchniques that were used to supplement this examination and obtain the best technologically sound examination available.

The indications noted were all subsurface circumlI'rcntial indications and of a size allowable per Tablc IWM1-3514-2.

Page 2 of 6

Attachment 2 to ULNIRC-05423

2. For1" wel 2-BB-OI-/F'202 the IVestDyne Interlnationial re/ort noted thut the licensee ohbtfined Ul)froximItttely 50% coverige o'fthe examnination volume. It wats a/lso noted that during the UT examnination one ASMIE Code-ualloiiahleindication wets identified. IProvide a brief discussion of the disposition of the inqicatielidentified during the UT examnination. In addition, did the indication extend into the ninsflIecCtahle vohume?

Response

During the examination of 2-BB-01-F202 100% of the volume was examined in the axial direction (looking for circumferential indications). The PDI qualification that the vendor was qualified to had the following statement of limitation: "This procedure/candidate is not qualified to detect axial flaws in either Supplement 2 or 10 welds which are not either ground smooth or machined smooth with no exposed root or counterbore." For 2-BB-014-i202, this condition was encountered. This resulted in no coverage under the rules of PDI for circumferential scans. This resulted in an aggregate coverage of 50% (i.e., 100%

from the axial direction, 0% frorn the circumferential direction). As such. the indication did not run into the uninspectable volume. See AmerenUE's response to Question 5 below for a discussion of other techniques that wcrc used to supplement this examination and obtain the best technologically sound examination available.

The indication noted was a subsurface circumferential indication, ol'a size that was allowable per Table IWB-35 14-2.

3. For 1-weld 2-BB-O1-F302 the WestDyne International irep)ort noted that the licensee oh(utind (approximately50% coverage of the examination volume. It wis l/so noted thatt during the UT examination one ASVE Code-allo/iiable indic'uionand one ASME Code non- allowable indication wiere identifted. Provide a hrief' discussion of/the disposition of these two indications identifiedduring the UT excimincition. ForPthei non-alloiiableindication,please provide the size of/th/

indication in comparison to the criteriagiven in ASME Code.Section XI, 1lVB

-3j00. hI adklition, did either of the indicationsextend into the uninsIpectble volhmvL?

Response

During the examination of 2-1B-01 -F302 10 0 % of the volume was examined in the axial direction looking for circumferential indications. The PlI qualification that the vendor was qualified to had the following statement of' limitation: "This procedure/candidate is not qualified to detect axial flaws in either Supplement 2 or 10 welds which are not either ground smooth or machined smooth with no exposed root or counterbore." For 2-BB-01-F302. this condition was encountered. This resulted in no coverage under the rules of' P)l for Page 3 of 6

Attachmnent 2 to ULNRC-05423 circumferential scans. This resulted in an aggregate coverage of 50)% (i.e.. 100%

froml the axial direction, 0% fromihe circumferential direction). As such, tile indication did not run into the umnispectable volume. See Question 5 below for a discussion of other techniques that were used to supplement this examination and obtain the best technologically sound examination available.

As noted in Question 3, there were two flaw indications on 2-113-01-F302. Flaw Indication #1 was determined to be subsurface and ol'an allowable size per Table IWB-3514-2. Indication #2, however, was determined to be surflace breaking and greater than the allowable flaw size per Table IWB-3514-2. Two independent evaluations were performed in accordance with IWB-3640, one by Structural Integrity Associates Inc., and the other by Westinghouse Electric Company LLC.

At AmerenUE's request. lbr the sake ofconservatismn and in both evaluations.

Flaw #1 was assumed to be surface breaking.

The results of both evaluations were that the Code-acceptable end-of-evaluation period flaw depth was well above that lor the conservatively calculated end-of-evaluation period using several very conservative crack-growth rate estimates.

these evalu'ations. as well as the associated Corrective Action Request (CAR) and Root Cause Evaluation, were provided to the regulator in accordance with IWB-3124.

4. F-mr welds' 2-BB-(1-FI02, 2-BB-01-1"'202, ain 2-BB-Ol-F3O2, ienmi/i, 1he weld anod base metal lnwtleritaL

Response

The weld and base metal material for all of the subject welds is stainless steel.

The safe end is lbrged stainless steel (SA 182 F3 16). the weld is a stainless steel weld (ER308). the elbow is statically cast stainless steel (SA 351 CF8A. which is the same as wvrought Type 304).

5. hI addition to the volhmetri" examination discussed above, 1he/ ISME Code requires a s.ftiwe examinationfor these welds. I'rovide the surfitce examination rc'sults off he stthject welds, ifperforbmed.

Response

These welds (all reactor pressure vessel nozzle sale end-to-pipe welds) are included in the RI-ISI Program at Callaway. The Category and 11Cm numnber were allowed to remain 13-.I and B9.1 1. respectively, for tracking PUrposes during the second inscrvice inspection interval. This was not communicated well in the request Imr rclicl For RI-ISI, the surface examination is not required. It should Page 4 of 6

Attachmcnt 2 to ULNRC-05423 also be noted that all eight inlet and outlet safe end-lo-pipc welds were examined during RI'I 3 even though only three were required For the RI-ISI Program Plan.

According to the IYesIDjYne ruepori, the licensee pfiwnrmcd ecc/c, c'turrent testing (ET) on wcld 2-BB-0133-F302. Discuss if ihe ET excuninuition was a subs!iftite.fir tie requlirLedxu.%'Ace examinations and was ET excaminalionpelu'fhnret on ii'elds 2-BB-01-FI02 und 2-BB F202 as iwell?

Response

The ET examination was performed to supplernent the UT examination of these welds as the PDI qualification did not include welds with root geometry. This was understood going into the examination. i.e., that the RPV nozzle safe end-to-pipe welds (which included 2-BB-01-F102. 2-BB-01-F202. and 2-13B-01-F302) were field welds, and as such were likely to have root geometry adverse to obtaining full coverage. In anticipation of this. ArnerenUE chose to perform ET and a UT ID surface profilometry (00 scan) to aid in evaluating the condition of the subject welds at Callaway.

6. Dulring the ET exxamination ?f ri'chl 2-BB-OI-F302. the licensee identfied tii'o inc/iculions, un11 these indicationswere assessed on .SWLei No. 247-SE-09 which aUs not Jri'idhc/ in thV licL'lsee's letter dated October 25. 2006. Provide e dLscriplion of/the ET.findings including asses.svnell Swect No. 247-SE-,09.

Response

As noted in the response to the second half of Question 5. the HT examination of the nozzle safe end-to-pipe welds was not a Code-required examination, but was identified by the vendor and accepted by ArncrcnUE as a good practice to provide a better examination of the subject welds at Callaway. The two indications were evaluated as follows:

ET examination of indication #2 confinred UT indication #2 which had been determined to be ID-connected. (See response to Question 3 above.) ET examination of indication #1 was conducted and evaluated, and it was determined to not be confirmatory with UT indication 41. However. as a conservative measure, UT indication #1 was assumed to be surface-connected in all engineering evaluations performed.

A copy ofliT Indication Assessment Sheet No. 247-DE-09 is provided/attached (as page 6 of 6).

Page 5 of 6

m wmspynl Page I of I ET INDICATION ASSESSMENT SHEET # 247-SE-09 utility: I AmerenUE Plant: Icallaway unit: 1 Outage: RF 13 Procedure No: WDI-STD-146 Procedure Rev. No.: I 1 Weld No: 2-BB-O1-F302 Total Number of Sweeps: 1289 ET Examiner Signature:

I File Name WN247-SE-PRP-SIZA 0C%

0%

WN247-SE-PRP-SIZA 0- >

Form 12.6

Attachment 3 to ULNRC-05423 REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST ISI-40

Attachment 3 to ULNRC-05423 REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST ISI-40 In the submittal dated October 25, 2006 (ULNRC-05183), Union Electric Company (the licensee) requested relief'(No. ISI-40).from certain requirements of the American Society of MechanicalEngineers Boiler and Pressure 1'essel Code at the Callamway Plant.

Specifically, the licensee requestedrelieff.rom the 100% volumetric coverage, preservice insIeccion requirements. The request is/nbr the second I0-year inser'vice inspection interval. To continue its review, the NRC stqff requests th.fbll/owing additional information:

I. Provide a cross section sketch identifj'ing the material (carbon steel, cast or wrought stainless steel. cast or"wrought nickel based alloys) in the weld region.

wall thickness at the weld, and describe or ske*tch the location and type of interf*,rence for each iwld.

Response

All of the welds addressed by Relief Request ISI-40 are stainless steel component (flange or valve, as appropriate) to wrought stainless steel pipe welds, examined in accordance with category 13-.i. The examination category R-A shown on page I of 3 of the relief request document rellers to the RI-ISI category. There are currently no RI-ISI preservice inspection (PSI) requirements provided by the ASME Code, so the PSI examination requiremcents revert to the Pre-RI-ISI category requirements (i.e., B-J). ASME Section XI 1989 edition Table IWB-2500-1 Category B-J Item B9.11 requires 100% volumetric examination as defined in Figure IWB-2500-1.

The following sketches, from the UT reports, are typical for the component welds addressed by ISI-40:

Page 1 of 5

Attachment 3 to UL.NRC-05423 6" Pipe to Flanpc Weld Comirenls: Weld Prolile and Scan Limitation Scan limilod to one side only due to flange, examinatlon volure considered 50% conplete in a.cuxdonce with APP. ViII requitemenits. Best effort exanninalion performed on the flanile side using reftractod Lwave.

Rafertnce UT Reorfl I'S UT,05-041. UT,05,042. UT,05.043.

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- * -- l 6" Pipe to Vah,e Weld Ccirnew.s: Wold Profile and Scan Limitation Scan limited to one side only duo t0 valve, examination volume considered 50% complete inl accordance with APP. VIII requirements. Best effort examination performed on the valve side using refracted L wove.

Reference UT Relorl Nrs UT.05-04T. UT.05-048. UT-05.049.

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.* ,3 ,7, .7 ,7 Page 2 of 5

Attachment 3 to ULNRC-05423

2. Discu.ss tihe nond'sti-uctive exctinhaiion(NDE) method used to /li h'eri/i' coiswtructioi inlegrity of thie i'ew welds, and discuss ihe volmnelric covera-ge achieved with the NDE method.

Response

ASM1E Section III governs construction NDE for the welds in question.

Specifically. all welds received radiographic and liquid penetrant examination.

No coverage issues were noted during the Section III RI'/Pf examinations.

3. Discuss the NDE methlod used to verb'5', the originalpluan co.sitruclioll welds, and discuss the vohumetric coverage achieved iiwith the NDEimethod.

Response

ASME Section Ill governed construction NDE fbr the welds in question.

Specifically. all welds received radiographic and liquid penetrant examinations.

No coverage issues were noted during the Section II1 RT/PT examinations.

4. Discuss oiher AIDE methods acnd ulirasonic testing (UT) techniques thiut were L'val'ated./or the reptair citmel r'eplaceientactivity, sue/i a* UT eaninitllionsfrom the insidce diatmeter, p/icsed atrracy on tapiered.l siritcev, w'e/d crowt' remow'l to inciLrease eirc.um.[r'eniial scamning, radiogrfal/h,', etc.

Response

AmerenUE is committed to utilizing the best available technology flor perlbrming ISI NDE at Callaway. However, the welds in question are for piping 6 inches or less in diameter. As such. there is no qualified technique for pCrlbrming UT examinations firom the inside diameter, including phased array. etc. The condition of the weld crown \\,as blended with an ISI prep. as required by the Callaway ISI Program For all ISI piping welds. Radiography was perlormed. as required by ASME Section Ill, Construction Code.

The examinations under consideration in ISI-40 were examined in accordance with PI)A-UT-2. PDI-UT-2 Step 1.8 states (in part and with emphasis added).

'"This procedure is not qualified flor...detection or length sizing of circuml'crentially oriented flaw indications when only single-sidcd access is aVailable and the flaw is located on the far side of the weld: however, guidance is provided. The techniques identilied in this procedure have been demonstrated to bh representative of the 'best effort' technology for single-side detection of far-side deli'cts parallel to the weld."

Page 3 of"5

Attachment 3 to ULNRC-05423 Therefore. the examinations performed at Callaway were based upon the best demonstrated technology available.

5. Dis'similarmetal (DMi) vchld" arc normally eyxminend iwith singlc-siducd qualyded procedia'esand pIe-sonnel. The diff[,erences betwvveen DM wi'e/ds and aenstenitic wveldis are the iweld sutrfiace comdition and adjoining base inetal coitolr. Discuss the applicabilityqf using Sec/ion XI. Appendix Vl/ll, Suplplemenl 10 qualcifed procccures and persolnel in lieu of Supplement 2 qualifications/o increatse the we/cl coverage. Include a discussion onl the effoirts to achieve an inspectable single-sided access con.figurattionf.orSuppleiieiut 2 and the demonstrattionson mockups for lesting d.fji.,nt NDE methods and techniqtuS.

Response

The welds in question arc not dissimi lar metal welds, therefore Supplement 10, "Qualification Requirements for Dissimilar Metal Piping Welds." was not applicable for these welds and was not used. Had AmcrenUE chosen to use Supplement 10 for these welds, it would have required submission of a request for relief in advance. H-owever. per discussion with EPRI personnel. because of the configurations involved (small bore piping to component welds) no increase in coverage could have been claimed. Therelore. ISI-40 would still have been required and the reliet'needed to use Supplement 10 instead of Supplement 2 as required would have caused unnecessary burden and cost, both to tie station and the regulator.

The industry efflorts to achicvc a qualified single-sided access examination per Supplement 2 are being coordinated through PDI and EPRI. ArnerenUE supports these cfforts, both financially and by participating in the PDI program. This is the appropriate research forum. as industry experts are actively engaged in advancing the technology of ultrasonic examinations.

6. Discuss the considcrtationgiven to atnozzle design that w'ould suplport the UT examinatlion coveragv fir the repairor rep)lacemenr oclivilv.

Response

The most inspectable. available component (i.e.. flange. valve) design was chosen, as required by I 0CFR50, Appendix A. Criterion 32. "Inspection of reactor coolant pressure boundary." None of the welds addressed in ISI-40 are nozzle welds.

Page 4 of 5

Attachment 3 to ULNRC-05423

7. These i'elds tre idenified cis part ofilhe risk-infirnted population which has if clr'icsshiglimile(l 'oel'-rgL'. Discuss lhu it, a /7s specific c'rieria.kfr I limited volumetric coverage will hovu on ithef/iiure exalminolaions of these welds in the risk-in~formedprogram.

Response

These welds were not selected by the risk-informed program for Callaway. There are no plans to examine these welds in the future.

Page 5 of 5