NL-07-121, Response to Second Request for Additional Information Regarding Relief Request 3-43 for Temporary Repair to Service Water Pipe

Response to Second Request for Additional Information Regarding Relief Request 3-43 for Temporary Repair to Service Water Pipe

ML072970095
Person / Time
Site:	Indian Point
Issue date:	10/05/2007
From:	Robert Walpole Entergy Nuclear Northeast
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-07-121
Download: ML072970095 (12)

Text

Entergy Nuclear Northeast Indian Point Energy Center En tergy 450 Broadway, GSB Buchanan, NY 10511-0249 Robert Walpole Licensing Manager Tel (914) 734-6710 October 5, 2007 Re: Indian Point Unit 3 Docket 50-286 NL-07-121 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Response to Second Request for Additional Information Regarding Relief Request 3-43 for Temporary Repair to Service Water Pipe

References:

1. Entergy letter NL-07-1 18 dated September 27, 2007 regarding Relief Request 3-43 for Temporary Repair to Service Water Pipe.

2. Entergy letter NL-07-120 dated October 3, 2007 regarding Response to Request for Additional Information for Relief Request RR 3-43.

Dear Sir or Madam:

Entergy Nuclear Operations, Inc (Entergy) is providing this response to a request for additional information regarding Relief Request RR 3-43 (Reference 1) as revised by Reference 2. NRC staff discussed this request for additional information with Entergy during a conference call on October 4, 2007. The additional information being provided (Attachments 1 and 2) does not result in a change to the Relief Request 3-43, Revision 1 submitted in Reference 2.

There are no new commitments being made in this submittal. If you have any questions or require additional information, please contact Mr. Robert Walpole, Manager, Licensing at (914) 734-6710.

Sincerely, Robert Walp ee Licensing Manager Indian Point Energy Center cc: next page AWGL7

NL-07-121 Docket 50-286 Page 2 of 2 cc: Mr. John P. Boska, Senior Project Manager, NRC NRR DORL Mr. Samuel J. Collins, Regional Administrator, NRC Region 1 NRC Resident Inspector, IP3 Mr. Paul D. Tonko, President NYSERDA Mr. Paul Eddy, New York State Dept. of Public Service

ATTACHMENT 1 TO NL-07-121 REPLY TO SECOND REQUEST FOR ADDITIONAL INFORMATION REGARDING INDIAN POINT 3 RELIEF REQUEST 3-43 FOR TEMPORARY NON-CODE REPAIR TO SERVICE WATER PIPING ENTERGY NUCLEAR OPERATIONS, INC INDIAN POINT NUCLEAR GENERATING UNIT NO. 3 DOCKET NO. 50-286

NL-07-121 Attachment 1 Page 1 of 4 REPLY TO SECOND REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 3-43 The following information is being provided based on a conference call between NRC staff and Entergy Nuclear Operations, Inc on October 4, 2007 regarding Relief Request (RR) 3-43 submitted September 27, 2007 (NL-07-118) and as revised October 3, 2007 (NL-07-120). This additional information does not change Revision 1 of RR 3-43 provided in the October 3, 2007 submittal.

NRC Question 1:

In Attachment 3, page 6, Section 6.3, the licensee stated that the minimum required wall thickness was determined by UT readings. In Section 6.4, the licensee stated that the wall thickness used for the Code case N-513-1 evaluation was based on the average value of the thickness around the thinned area of the pipe.

(a) Discuss why two different approaches are used to in determining the wall thickness.

(b) Discuss for each approach whether the conservative wall thickness is used.

(c) Explain Item 2 in Section 6.3.

Entergy Response:

a) There are two thickness values established for two different purposes in the flaw evaluation provided as Attachment 3 to the Entergy letter dated October 3, 2007.

1. The minimum required wall thickness was calculated based on the USAS B31.1.0 Power Piping Code using the highest value of:

i) The stress value based on the pressure / hoop stress, ii) The mechanical stress, or iii) The administrative limit of 20%.

For this situation, the pressure / hoop stress is limiting. This is the approach used for establishing the wall thickness acceptance criterion limit for identifying a flaw.

2. The other wall thickness value used in Attachment 3 is developed based on results of field measurements obtained using ultrasonic testing (UT). This wall thickness value is used for evaluating flaw acceptability per Code Case N-513-1.

b) The wall thickness values for both purposes are conservative. Calculation of minimum required wall thickness incorporates the inherent conservatism from the Power Piping Code.

Determination of wall thickness based on UT measurements conservatively used that average thickness in the vicinity of the flaw instead of averaging the larger thickness around the entire pipe.

c) The method discussed in item 2 of section 6.3 of the calculation describes the method of increasing the calculated pipe stress to account for the reduced section of the metal due to corrosion. There are two methods that can be used; 1) assume the pipe is uniformly thinned around the entire pipe based on the lowest measured value or 2) calculate the section modulus and other properties based on actual UT measurements. For this situation, Entergy used method 2. Code Case N-513-1 requires that periodic examinations of no more than 90-

NL-07-121 Attachment 1 Page 2 of 4 day intervals be conducted to verify values used in the flaw growth evaluation. Entergy expects to implement a repair before the next examination is due.

NRC Question 2:

In Attachment 3, page 6, Section 6.6, the licensee referenced the 1995 edition of the ASME Code, Section Xl, Appendix H in evaluating the flaw(s). However, as stated on page 1 of , the code of record is the 1989 edition. Explain why the 1995 edition of the code is used.

Entercv Response:

The Klc and JIc values needed for the flaw evaluation are not reported in the 1989 Edition of Section XI, so the procedure for flaw evaluation references the 1995 Edition for these values.

The current code of record for repair and replacement activities at IP3 is the 2001 Edition through 2003 Addenda, as explained on page 1 of Attachment 2. Entergy has confirmed that coefficient values used in the flaw evaluation are consistent with the code of record.

NRC Question 3:

In Attachment 3, page 7, the licensee used 1.00 for the stress intensification factor (SIF) of the leak location. As the licensee indicated the value of 1.00 is for a pipe configuration. However, the pinholes are located in the part of the elbow, albeit on the straight end/section of the elbow, as shown in the photos that the licensee provided to the NRC. In addition, the pin holes are located close to the weld joining the elbow to the flange. The pinhole location would experience stress concentration because of their proximity to the weld. The purpose of the SIF is to model the piping loads in the analysis to account for the stress concentration at a piping location due to configuration or discontinuity. The staff believes that a SIF for the elbow should be used which is higher than 1.0. Justify why the SIF of 1.0 is acceptable.

Enterqy Response:

The SIF of 1.0, actually a value of .75i equal to 1.0, was used to remove the over conservatism caused by using the Elbow SIF over the entire length of the elbow. As the Companion Guide to the ASME BPVC, page 555 states "the SIF at an elbow is maximum at the 45 degrees location."

This accounts for the bucking at the out of plane which occurs at the center of the elbow only.

Since the leak and thinned area is approximately 3" from the elbow weld, an SIF for a straight pipe was used. In addition, since the flaw is near the weld to the flange an as-welded SIF can be used. For the B31.1 1967 edition of the code the as-welded SIF is 1.3, therefore the .75i would also be 1.0.

NRC Question 4:

In Attachment 3, page 10, the licensee showed the equations for Fm and Fb, the parameters for circumferential flaw, are calculated. However, the equations and associated coefficients do not seem to be consistent with that of Appendix H of the ASME Code Section Xl (the 1995 edition).

Explain.

NL-07-121 Attachment 1 Page 3 of 4 Enterqy Response:

The equations and coefficients are taken from Appendix I of Code Case N-513-1. The numbers displayed on calculation sheet are truncated to fit the spreadsheet format used for the calculation.

NRC Question 5:

In Attachment 3, page 11, the licensee stated that after weld overlay the SIF needs to be 2.1 for even a straight pipe. Explain why a SIF of 2.1 is used after weld overlay.

Enterqy Response:

This is from the requirement of Code Case N-661. The calculation was performed assuming the possible repair was going to be a weld overlay. If an overlay was performed then the code case requires an SIF of 2.1. This is derived from the as-welded SIF requirements contained in the later code versions. The statement is intended to state that stress requirements are met with the repair and an SIF of 2.1.

NRC Question 6:

Section 2(e), 2(f), 2(g), and 2(h) of Code case N-513-1 requires frequent periodic inspection or performing a flaw growth evaluation. Please address the requirements in each of these sections because it is not evident in the submittal that the licensee has met the requirements of N-513-1.

Enterpy Response:

Entergy is implementing the requirements of Sections 2(e), 2(f), 2(g), and 2(h) of Code case N-513-1, where applicable for this situation. Evaluation of the flaw has been completed per Section 2(e) and as documented in the calculation IP-CALC-07-00083 provided to NRC (Attachment 3 of Entergy Letter NL-07-120 dated October 3, 2007). The operability evaluation performed for this condition recommended a 30-day time frame for completing a repair.

Therefore, Code Case 513-1 requirements in section 2(e) that extend beyond 30 days would not be applicable, unless new data and an updated evaluation support a repair timeframe of longer than 30 days. Daily walkdowns are being performed per Section 2(f). Sections (g) and (h) pertain to performing a repair or replacement. Entergy is requesting NRC approval of Relief Request 3-43, Revision 1 to support our planned repair.

NRC Question 7:

For the flaw characterization and evaluation, identify any deviation from Code Case N-513-1 and other applicable code guidance or requirements including justification.

Enterqy Response:

Entergy is following the requirements of Code Case N-513-1 for flaw characterization and evaluation as documented in Entergy Calculation IP-CALC-07-00083.

NL-07-121 Attachment 1 Page 4 of 4 NRC Question 8:

Discuss and provide a report to show how the corrosion rate of 0.012 inches per year was determined. Discuss and provide the results of local corrosion rate.

Enterqy Response:

The corrosion rate value of 0.024 inches per cycle, or 0.012 inches per year is a historical value developed over several years of evaluating service water piping systems and corrosion degradation at IP2 and IP3. There is not a reference document for this value. Local corrosion rates can depend on many factors and Entergy has not developed a standard value to be assumed for local corrosion. The proposed repair does not depend on a precise value for corrosion rate, because Entergy will be monitoring for additional degradation and repair integrity by daily walkdowns and periodic UT examinations as stated in Section E.4 of Relief Request 3-43 and in response to NRC Question 10.

NRC Question 9:

Identify the code requirements for design, fabrication and NDE of the proposed repair (plate and weld). Identify any deviations from such code requirements with justification.

Enterqy Response:

The code requirements for design, fabrication, and NDE of the proposed repair are per original design requirements in B31.1 (1967). There have been no deviations from this code.

NRC Question 10:

Perform UT examination on pipe area adjacent to the repair weld (a band of three inches) to monitor the extent of degradation.

Enterqy Response:

The scope of the inservice monitoring described in Section E.4 of Relief Request 3-43, Revision 1 will include UT within a 3-inch band around the top and side perimeters of the repair weld to monitor for degradation. The base of the repair weld is adjacent to the bolting flange for this elbow, so that a full 3-inch band is not available. The UT will extend as far as practical beyond the base of the repair.

NRC Question 11:

Please provide the UT report for the measurements recently taken using a 1/4-inch grid.

Entergy Response:

UT Report IP3-UT-07-1 11 using the 1/1/4-inch grid is provided in Attachment 2. This UT exam provides for a more detailed inspection of two regions within the coverage of the UT exam previously performed with a 1-inch grid as documented in UT Report IP3-UT-07-110.

ATTACHMENT 2 TO NL-07-121 REPLY TO SECOND REQUEST FOR ADDITIONAL INFORMATION REGARDING INDIAN POINT 3 RELIEF REQUEST 3-43 FOR TEMPORARY NON-CODE REPAIR TO SERVICE WATER PIPING Ultrasonic Test Results for Area Downstream of SWN-38 IP3-UT-07-1 11, September 2007 (1/4" grid)

ENTERGY NUCLEAR OPERATIONS, INC INDIAN POINT NUCLEAR GENERATING UNIT NO. 3 DOCKET NO. 50-286

EIN.,,I Dt*- .! N)ic10 MI/A

. . .i..- 1 Rup)orl, No.: lP3-UIT-07-1 vi V/OilP01det No.: 00123409-02 Page: 1 01 4 AI 1'i'.1 1967 Ed. l hru 1969 Add. Catiltem. N/A Location: PAB / Minim Containment m', ;niav o..'

¢: 9321-F-27223 Descriplion: Characterize areas of wall thinning, reference report IP3-UT-07-110.

System ID. Service Watel Colipunr-SCo, ID: 18" Line t 408 DIS of valve SWN-38 Size/Length: 18" Sch STD Thickn ess/Diameter: 0.375" Lniiiiatlsonrm N'one Component File No.: SWN38-SM1 & SM2 Start Time: 1200 Finish Time: 1530 Calibration Information Partitioning Information Component Information

-r Calibration Times / Initials Component Begin/Col/Row Ending/Col/Row Component Geometry: Pipe Elbow

.040" .500" Start: 1300 REA M. UPST Ext. N/A Outside Diameter: 18" Grid Size: .25"x.25"

.100" N/A Verity: 1325 REA Main UPST. N/A Max. Thickness: .254" Min. Thickness: .032"

.200" N/A Verify: N/A Main N/A Nominal Thickness: .375" Tmin.: .090"

.300" N/A Verity: N/A Main DNST. N/A Min. Thickness Location: SM2 location J5 & K5

.400" N/A Final: 1355 REA M. DNST Ext. N/A Branch N/A Max. Thickness Location: SM2 location A9 Branch Ext. N/A Instrument:

Transducer: Reference/Simulator Block: Temp. Tool:

Maaer Pnmti Manufacturer: Panametrics Serial No.: A23867 Manufacturer: Control Co., Inc Mel. 31010 Serial No.: 536066 Type: C/S .04"-.5" Serial No.: OS-77 Serialno.: 03111106 dSize: 0.2" Freq.: 7.5 MHZ RefiSimulator Block Temp.: 87.1 'F Couplant:

Gain: 50 dB Model: D798 Type: Ultragel Range: 1.0" # of Elements: Dual Material/Component Temp.: 84.7 "F Batch No.: 05325 Comnents/Obstructions: Sub-micro grid of the thinner elbow areas show by report iP3-UT-07-110.

Results: Accept Reject ': Info Tmin = .090" per IP-CALC-07-00083.

Examiner Level III-PDI Sib re Date I Reviewe1 Signature Date Allen II, Robert E. -\-r,,*j ,. 9/20/20071 Examiner Level N/A Sid'tature Date 'Site Revie N/A N/A L ovt I N/A h2T3U Date ANII Review A-Ll i lare SignatureI V qj a 1 N/A r ~Date.

stippIerflCoftal R~eport I tP2'ý-UT-O7-1 11 I: !//0r2X' 2 nI 4 un iiry No.: 18" Line V 408 L:Xarnincr: Level: III-PDI Reviewer: Dale:

Allen I1,Robert E.

Oh xaminer: N/A LeveL: N/A Site Review: ItI1&// k Daii' Other: N/A Level: N/A ANtI Review: e4 Date:

Comments: Sketch of sub-mirco grid shown below superimposed over the micro grid established by report IP3-UT-07-110.

Sketch or Photo:

42~ S*I~I c F 14

WinmDLPWus,.ta Grid 18" Line # 408, DIS . lve SWN-38 I Fife Name *SWN38-SM1 Survey Date: 9j2012007 File Type. 2D Grid Minimum thickness; .061" 65 File De-crlpticiil Sub-Micro Grid 1 Maximum thickness: .184" A9 Lo :ation Note :P3 Report No,; IP3-UT-07-1 II lrerec ID : Page 3 or 4 R:'c'efl Aireri 4A1 FeLwr UU I.:A JB I c D jE (nIMax V Abg Color Legend OJS3 0.140 e,122 D.115 0,140 0,115 0,153 0.134 0.128 1 0.116 4 o..ill 0,152 0.184 0.168 0.117 f-0.s50- 0.184 0.150 0.16, 0.162 0.118 0.125 0,146 0.115 ~4-409-0.0 0.154 0.IZ4 0,14J, 0.114 0 148 0.140 0.134 0.116 0.184 0.142 Fo-..-

S0,030 0.168 0.1311 0.118; O.14 TAvg Page 1 Report Date: 9i24i2007

Win37DLPlus).ta Grid 18"Line # 408, D;S Ave SWN-38 SWVN38-S(\2 Survey Date : W12012007 FOLe Type 2D Grid Minimum thickness: .032"l J5 & K6 Fi eE i, :,i ion c~.; Sub-vMiro Grid 2 Maximum thickness: .254- Ag lPS, Report No,: IP3-UT-07-1 11 Luc a~tion Not Page 4 of 4 Rev iwer 'JfLA.#~~ d i

IL IM IN' 10 IP IQ Coloi Legend IC ID E IF IG IH I'1 11 1 IMin I Max jAvg 0,187 0,181 0.156 0.172 0.200 0.205 0,216 0.225 0.226 0.156 0.26 0.1" MJL 0.208 0.211 0.192*J 0.1.9 0.202 0,157 0.143 0.11IS 0.i18 0.135 0.211 0205 0.215 UP7 0.237 0.171 0.179 0.212 4 0.m 0.193 0.216 0228 0238 0.238 0.150 0.186 0.197 0.175 0,130 0,..114 Ol 0.180 0.179 0215 0234 0.234 0,140 0 .17 0.166 0.178 0.161 0.199 0.216 0.233 0.233 .2 2 0.176 0.159 0 .162 o1,2 0.164 0.141 0.149 0.114 ~ON 0127 0.14S 0*148 0.126 0. 110 0.1" 0.21 o13 0.13- 0.126 0.130 0.221 0200 0.229 0.229 0.118 0 12 0.152 0.112 0.141 0.172 0,221 0,222 o0226 0o226 o.0 0,174 01,2 0.166 0,19S 0 121 01157 0.175 0.112 0.122 0.114 0,119 0. 123 0,149 0.156 0.197 0.186 020 1 0,228 0 254

.12 0.163 0.1060 0-254

" 0ý o.147 0.12& &jjj-..` 0.179 0.200 0.221 oL123 0.208 0.212 0202 0.199 0.187 0.181 0.156 0,172 0.200 0.211 0221. 0228 0 238 0.254 0.166 0.19 0,152 0,170 0.140 0.127 - 7 0.131 0.16S 0204 0.215 0.230 0.171 0.117 0,125 0.112 0.167 f-Under Rzr~gý 0.254 TA ;.1 0.,145, Page 1 Report Date: 9W24J2007