ML101190417

Westinghouse Electric Co., LLC, LTR-SGMP-10-50 NP-Attachment Assessment of the Effect of the Location of the Bottom of the Expansion Transition on H.

ML101190417
Person / Time
Site:	Millstone
Issue date:	04/22/2010
From:	Dominion Nuclear Connecticut, Westinghouse
To:	Office of Nuclear Reactor Regulation
References
10-276, FOIA/PA-2011-0115
Download: ML101190417 (19)

Text

I Serial No: 10-276 Docket No. 50-423 Enclosure 4 Westinghouse Electric Company LLC, LTR-SGMP-10-50 NP-Attachment "Assessment of the Effect of the Location of the Bottom of the Expansion Transition on H*," dated April 22, 2010 NON-PROPRIETARY DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3

Westihghouse Non-Proprietary Class 3 LTR-SGMP-10-50 NP-Attachment Westinahouse Electric ComDanv Assessment of the Effect of the Location of the Bottom of the Expansion' Transition on H*

April 22, 2010 Westinghouse Electric Company LLC P.O. Box 158 Madison, PA 15663

© 2010 Westinghouse Electric Company LLC All Rights Reserved

LTR-SGMP-10-50 NP-Attachment Assessment of the Effect of the Location of the Bottom of the Expansion Transition on H*

Introduction The alternate repair criterion, H*, replaces the tube end weld as the pressure boundary between the primary and secondary sides of the steam generator with the hydraulic expansion joint between the tube and the tubesheet. The technical justification of H*

demonstrates that the hydraulic expansion joint between the tube and the tubesheet provides adequate capability to satisfy the applicable structural and leakage performance criteria. The technical justification determines the required length of non-degraded tubing within the tubesheet expansion region to assure that the tube cannot be pulled from the tubesheet by the limiting axial (end-cap) loads for normal operating conditions and for the limiting design basis accident with appropriate safety factors as

.specified in Reference 1. The H* technical justification also shows that any leakage through the joint is less than the leakage assumed in the Final Safety Analysis Report for the limiting accident conditions. The proposed inspection depth of 13.1 inches includes a large margin compared to the minimum depth required to meet the performance criteria.

Regular in-service inspections in accordance with the requirements of Reference 2 verify that the tubing within the tubesheet expansion region is not degraded by stress corrosion cracking over the required length that is defined as H*. To accomplish this, it is necessary to establish a unique, repeatable frame of reference. The top of tubesheet (TTS) is a point of reference that is established by current eddy current techniques and instruments (such as the bobbin probe). Consequently, the TTS is the point of reference chosen for H*. The conservatively recommended H* distances are specified as being measured from the TTS.

The H* technical justification depends on contact between the tube and the tubesheet due to pressure loads, thermal loads and residual loads from initial installation (hydraulic expansion). As a minimum, this technical justification assumes that line-on-line contact exists between the tube and the tubesheet over the length of the hydraulic expansion. The manufacturing process requires a tolerance of approximately [ ]a,c,e inch from the TTS to assure that overexpansion above the TTS does not occur. Thus, by design, there is a short span from the TTS to the bottom of the expansion transition (BET) region where the assumption of line-on-line contact is not valid. The hydraulic expansion process is designed to minimize the distance from the TTS to the BET; however, the exact position of the location of the BET relative to the TTS can vary due to manufacturing tolerances.

To address the potential variation of the location of the BET, the technical justification for H* includes a constant value of 0.3 inch for the location of the BET. Multiple studies on different steam generators have shown that the 0.95 probability with 95% confidence (95/95) location of the BET is approximately 0.3 inch from the TTS (Reference 3). This factor is added as a constant to the calculated H* distance required to meet the Page 2 of 8

LTR-SGMP-10-50 NP-Attachment performance criteria because the underlying assumption of the H* calculation is that the initial condition is line-on-line tube to tubesheet contact.

The recommended values of H* at 0.95 probability and 50% confidence (95/50) for the Millstone Power Station Unit 3 (MPS3) steam generators are provided in Reference 3.

Reference 3 recommends a 95/50 H* value of 11.2 inches; however, MPS3 has chosen to use a H* inspection depth value of 13.1 inches for additional conservatism. In response to an NRC request for additional information (RAI), additional information on the probabilistic values of H* was provided in Reference 5.

As requested in Dominion Nuclear Connecticut, Inc. (DNC) Letter 09-525, a request for licensing of a one-time alternate repair criterion, H*, DNC committed to "perform a one-time verification of the tube expansion to locate any significant deviations in the distance from the top of the tubesheet to the bottom of the expansion transition (BET). If any significant deviations are found, the condition will be entered in the plant's corrective action program and dispositioned. Additionally, DNC commits to notify the NRC of significant deviations."

This document provides an assessment of the effect of variations in the depth of the BET on the calculated values of H* length to determine the value of the BET position beyond which will be considered "significant." This value has been determined to be 1.0 inch for the MPS3 steam generators due to available margins as discussed below. As shown in Table 1 of this correspondence, seven tubes have been determined to have BET located below 1.0 inch from the TTS in the MPS3 steam generators.

Table 1 MPS3 Tubes with BET Greater Than 1 Inch That May Reduce Inherent Margins for a 13.1 inch Inspection Depth SG Row Column BET Radius 3AH 15 61 -1.16 15.928 3AH 12 59 -1.25 13.209 3AH 11 50 -1.07 16.462 3AH 11 60 -1.22 12.090 3AH 9 52 -1.03 13.692 3AH 6 59 -1.65 7.511 3AH 13 60 -1.74 14.037 Analysis Summary Table RAI20-5 of Reference 5 provides a value for H* of [ ]ac~e inches for the Model F steam generators at 95/50. This value for H* includes the effects of surface sampling from Figure 8-5 of Reference 3 with a limited number of tubesheets, a sector based approach, and a thermal offset correction factor. Conservatively, a similar value has been determined for the case when the whole plant complement of tubes is considered Page 3 of 8

LTR-SGMP-10-50 NP-Attachment (22504 tubes). This value was not previously provided in Table RAI20-5 and is based on computations performed with the full Monte-Carlo simulation model (See columns (b) and (c) of Table 2 of this correspondence). The issue consisted of obtaining a suitable correction factor to obtain a 95/95 extreme value for H* applicable to the full plant from a 95/50 whole bundle estimate which does not include the effect of residual contact pressure. Explicit computations were performed which resulted in the choice of a multiplicative correction factor of [ ]ace (column (e) of Table 2) to be applied to the 95/50 whole bundle estimate. The evaluation at the higher confidence of 95/95 increases the required H*from [ ]a,c,e inches to [ Iac,e inches ([ ]a,c,e inches times the correction factor of [ ]a,c,e = [a,c,e inches).

Table 2 H* Correction Factor Simulation H* Result- H* Result- Additive Correction Multiplicative Method 95/50 Whole 95/95 Whole (in) Correction Factor Bundle (in) Plant (in) ()

(a) (b) (c (d) (e)

Monte 'Carlo Ia,c,e Ia,c,e ]a,c,e I a,c,e Therefore, the proposed inspection depth of 13.1 inches provides at least a [ a,c,e inch margin to the most conservative prediction of H* of [ ]a,c,e inches. This value compares favorably to the maximum value for BET determined in the MPS3 steam generators of 1.74 inches.

The choice of a multiplicative adjustment assures a conservative estimate when compared to the somewhat lower additive 95/95 estimate of [ ]a,c,e inches ([ ]a,c,e inches + [ ]a"ce inches (column (d) of Table 2 above) obtained using the Monte-Carlo analysis results. The proposed multiplicative correction factor is essentially equivalent to the same correction factor that would be defined using the Square Root Sum of Squares (SRSS) results included in Table 3 of Reference 4 ([ ]a,c,e [ ]a,c,e inches/1 1.2 inches).

It is not considered credible that a 0.7 inch change in the location of the BET (1 inch compared to the 0.3 inch value of location included in the H* analysis) will cause a change in the predicted value of H*of greater than [ ]a,c,e inches. Therefore, a 1 inch location of the BET is not considered to be significant to the application of H*.

Effect of Radial Location of Tube on H* Length The row and column location of a tube that exhibits a BET measurement value greater than 0.3 inch is also an important factor in assessing the impact of the BET measurement on H*. In determining the H*value, it assumed that every tube is located at the worst-case position in the bundle. However, H* is a radius-dependent value as shown in Figure RAI20-1, Model F: Normalized H*for Various Tubesheet Sections of SGMP-09-100-P (Reference 5; note this information was provided in the original MPS3 Page 4 of 8

LTR-SGMP-10-50 NP-Attachment license amendment request (LAR) submittal dated November 23, 2009). Figure RAI20-1 shows the radius-dependent calculated values of H* normalized to the maximum value of H* at the limiting location in the bundle. At the limiting location, the normalized value of H* is 1. The normalized values of H* decrease at all other radii in the bundle; thus the margin between the inspection depth and the radius dependent H* value is greater for all tubes at locations other than the limiting location.

The LAR value of H* is based on the radial worst case position in the tube bundle at I I]a,c,e inches radius shown in Reference 3. The value of H* at all other radial positions is less than the limiting value at the critical radius. Additional margin beyond the inherent margin in the requested inspection depth is available at all of the non-critical radii. This additional margin can be used to accommodate locations of the BET relative to the TTS.

At MPS3, there were tubes identified with larger than a 0.3 inch BET position relative to the TTS. The radial position of these tubes on the tubesheet is readily calculated from their row and column positions, the tube pitch ([ ]ace inch) and the bend radius of the row 1 tubes ([ ]a,c,e inches). Knowing the radial position of each tube, the position-specific value of H* can be determined from Figure RAI20-1 of Reference 5. Figure RAI20-1 providesthe normalized position-dependent values of H*for the Model F steam generator. For example, at [ ]a,c,e inches radius, the limiting radius, the normalized value of H* is 1. This is the position that determines the licensed value of H*, 13.1 inches. At radius 11.8 inches, the normalized value of H* is approximately I ]a,c,e, indicating the necessary H* depth at that location is [ ]ace inches, including all of the margins represented by the LAR inspection depth value of 13.1 inches. Therefore, at a radial position of 11.8 inches, an additional margin of [ ]a c,e inches exists if the LAR inspection depth is 13.1 inches.

The actual inspection depth for refueling outage M3R13 is 15 inches. The difference, between the LAR requested inspection depth of 13.1 inches and actual inspection depth of 15 inches provides an additional margin of 1.9 inches.

Table 1 of this correspondence identifies the MPS3 tubes that have BETs located greater than 1.0 inch below the TTS and, therefore, may have reduced margins relative to the requested inspection depth of 13.1 inches. When adjusting for tube position in the tubesheet using the most conservative assumption, i.e., with 1.0 inch considered the limiting value of BET position, no tubes have a negative impact on the margin inherent in the 13.1 inches inspection depth based solely on location of the tube in the tube bundle.

Effect of BET Depth on H* Length The structural calculation of the H* value depends on the deformation of the tubesheet due to thermal and differential pressure loading. These loads result in a contact pressure profile through the thickness of the tubesheet. Assuming that the tube and the Page 5 of 8

LTR-SGMP-10-50 NP-Attachment tubesheet are not initially in contact for some distance, i.e. 1.0 inch, from the TTS, it is reasonable to consider if the predicted necessary length of tube in contact with the tubesheet would be affected. The answer to the question is important to consider because the actual length of tube in contact with the tubesheet at any given position in the tubesheet must provide essentially the same margin against tube pull-out as that assuming tube to tubesheet contact exists over the-full inspection length of the tubesheet regardless of the BET offset. A specific numerical solution would require complete re-analysis of H* based on the postulated assumption of where tube to tubesheet contact begins (i.e., a postulated location of the BET). However, based on the experience of the H* analysis model developments and multiple sensitivity studies, a sound engineering judgment is possible to address the postulated case.

H* is essentially an integration of the contact pressure profile from the TTS downward to determine the axial position at which the integrated resisting forces are equal to the applied pullout forces. Therefore, the rate of change (slope) of the contact pressure profile from the TTS is a reasonable indicator of the effect on H* of a postulated TTS non-contact initial condition. At the limiting tubesheet radius for H*, the slope of the contact pressure curve is positive with increasing depth into the tubesheet. Also, the tubesheet displacements below the TTS elevation decrease around the circumference of the tube outside diameter (OD), resulting in a tighter tubesheet bore. Thus, the predicted H* distance under postulated TTS non-contact conditions would be expected to decrease because the rate of increase in contact pressure from the top portion of the tube in contact with the tubesheet to the H* depth would be greater.

At the smallest tubesheet radius, the contact pressure curve is initially negative for a short distance (<2 inches) and then becomes positive with increasing depth into the tubesheet. In aggregate, a shorter length of tube in contact with the tubesheet would be predicted to result in the same pullout margin. For the largest tubesheet radius, where the H* margin is the greatest, the slope of the contact pressure curve is negative for the entire thickness of the tubesheet from the TTS to the bottom. For this location, a small increase in the necessary tube to tubesheet contact length could.be expected if it were assumed that the BET is located at 1.0 inch below the TTS; however, this increase would be expected to more than adequately be offset by the maximum H* margin at this location.

In summary, while no specific analysis has been performed, based on the prior preliminary scoping analysis of model development and scoping studies performed during the H* analysis, it is judged that no negative impact on the predicted value of H*

would occur if it were assumed that the location of the BET is 1.0 inch below the TTS.

Assessment on the Steam Generator Plugging Criteria The current suggested steam generator plugging criteria is appropriate. The analysis above demonstrates that (1) the margin inherent to H* is sufficient to accommodate observed variations in the location of the BETs in the MPS3 steam generators (2) with -

Page 6 of 8

LTR-SGMP-10-50 NP-Attachment 1.0 inch considered the limiting value of BET position, no tubes have a negative impact on the margin inherent in the 13.1 inches inspection depth based solely on location of the tube in the tube bundle, and (3) a preliminary scoping analysis supports no change in H* length is necessary for BET values less than 1.0 inch from the TTS.

Additionally the underlying basis of H* is that a complete severance of the tubes is assumed at, or below, the H* inspection distance. The MPS3 LAR includes a commitment to sample for tube slippage on a periodic basis. Slippage monitoring is accomplished by monitoring for a large bobbin signal in the tubesheet expansion region.

MPS3 has performed 100% bobbin inspections of the steam generators during the recent steam generator outage as reviewed by NRC letter dated December 22, 2009 (Reference 6). No large bobbin signals have been observed; thus, it is concluded that no tube severance or slippage has occurred. The Normal Operating Pressure condition is shown in Reference 3 to be the limiting condition for H*; thus, the absence of severance and slippage of tubes is proof that the tubes remain in a safe condition, regardless of the known position of the BET at MPS3. Until such time that a severance is shown to occur in any tube with a significant variation of BET position, there is no need to plug that tube.

Summary and Conclusions Based on the above, it is concluded that:

1. The current requested LAR inspection depth of 13.1 inches provides significant margin over a 95/95 whole plant value calculated for H*which does not consider the effect of residual contact pressure;

2. The available margin between the requested H* inspection depth of 13.1 inches is I ý]a,c,e inches at the limiting position in the bundle.

3. The margin between the requested inspection depth and the calculated H* values increases as the position of the tube in the bundle varies from the limiting position.

4. A variation of the BET position to a value of 1.0 inch below the TTS, compared to the 0.3 inch uncertainty already included in the calculated values of H* is readily, accommodated by the available margins between the planned inspection depth and the calculated H* values.

References:

1. NEI 97-06, Rev. 2, "Steam Generator Program Guidelines," May 2005.

2. EPRI 1013706, "Steam Generator Management Program: Pressurized Water Reactor Steam Generator Examination Guidelines: Revision 7," October 2007.

3. Westinghouse Electric Company LLC, WCAP-17071-P, Rev. 0, "H*: Alternate Repair Criteria for the Tubesheet Expansion Region in Steam Generators with Hydraulically Expanded Tubes (Model F)," April 2009 (Proprietary).

Page 7 of 8

LTR-SGMP-10-50 NP-Attachment

4. Southern Nuclear Operating Company, Inc. letter NL-09-1317, "Supplemental Information for License Amendment Request to Revise Technical Specification (TS)

Sections 5.5.9, "Steam Generator (SG) Program" and TS 5.6.10, "Steam Generator Tube Inspection Report" for Permanent Alternate Repair Criteria," August 28, 2009.

(Transmittalof Westinghouse Electric Company LLC letter LTR-SGMP-09-104-P Attachment, Rev. 1 "White Paperon ProbabilisticAssessment of H*, dated August 13, 2009, NRC ADAMS Accession Nos. ML092450030 (Proprietary)and ML092450029 (Non-Proprietary).

5. Westinghouse Electric Company LLC, LTR-SGMP-09-100 P-Attachment, "Response to NRC Request for Additional Information on H*; Model F and Model D5 Steam Generators," August 12, 2009 (Proprietary).

6. Letter dated December 22, 2009, C, J, Sanders, USNRC, to D. A. Heacock, Dominion Nuclear Connecticut, Inc., "Millstone Power Station, Unit No. 3 - Review of the 2008 Steam Generator Tube Inservice Inspection Report (TAC No. ME0942)."

Page 8 of 8

Serial No: 10-276 Docket No. 50-423 Enclosure 5 Westinghouse Electric Company LLC, CAW-10-2803, "Application for Withholding Proprietary Information from Public Disclosure," dated April 22, 2010 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3

SWestinghouse Westihohuse EletricCompany Nuclean Service P.O.:Box 355 Pittsburgh,'Pennsylvania 1,5230-60355,'

U.S. Nuclear Regplatory Commission Direct tel: (412)1374-4643 Document Control Desk 'Direct fax: (.412)374-4011 Washington, DC 20555-0001 e-mail: greshaja@Westinghouse.cbm CAWN- 0-2803 Apr0il22, 201.0 APPLICATION FiIORWITHHOLDING. PROPRIETARY INFORMATION FR'OM PUBLiC DiSCiLOSURE Subject-. LTR-SGMP- 10-50:)P-Attachment, '!Assessment of theEffeci of the Locaiion of theBottom of the Expansion Transition. on.H*;" dated April 2010 (Proprietary)

The'prop-ieary ihformation: fori which withholdiing is being requested in the above-referenced report is further identified in Affidavit CAW-10-2803 signed by the owner of the proprietary informationi Westinghouse Electric 'Company LLC. Theaffidivit, .WhIich accompanies this ietter, sets fortdhthe basis" on which'the 'information m"ybe .withheld~froni public disclosure by the Commissi6n and addresses with specifiettytheconsideratins listed'i paragraph

" (b)(,4)of. 10 CFR Sectfin 2.390. ofthe Commission's regulations.

Accordingly;, this: letter auth6rizes the utilizationvbf the.'accdmpanying affidavit by Dominion NucItear Connecticut, J'nc.

Correspondence with respect to',the:proprietaryaspects of the application for'Withholding or the Westinghbuse~affidai~it'shoutld reoferen~ethiselter, CAW-ý1'0-2803;.zand ýshould be. addressed to a ger, Rglatory o Westinghouse Electric Company LC, VoP.O Box 3'5, Pittsburgh, ,Pennsylyvania 15230-03S5.

-Vey trUly yours,.

aA.

ni, Manager Regulatory Compliance and Plant- Licensing Enclosures

CAW-10-2803 April 22,120110.

b~c6:, J A. Greshjfim "C.B. Brinkman

,C: L.Olesky G,. W. Whiterman H:H.O. Lagally DA. Testa, D.L. Rogosky C.W. Nitchman

)

CAW-1ý02803 AFFIDAVIT COMMONWEALTH- OF PENNSYLV'ANIA:

ss COUNTY OF:ALLEGHENY:

Bef6re be, the unders'ign'edauth6rity..personaly a JPJearedJ.

A. Gresliiam, who,,beingby me'b duly sw6m accordinig to laWdep6oes and says that he isauthorizedto: execfute'thisAffidaVit,0n behalfobf Westinghouse Electric Compianiy LLC (Westinghouse); and that the averments§of fact setTforth in this Affidavit are true and correct to the best of his knowledge, information, and belief:;

J., A. Gresham, Manager Regula4topyCompliance and Plant Licensing:

Sworn'to and.subscribed before me this 22nd dayof April 2010 Notary Public COMMONWEALTH OF PENNSYLVANIA

!NOTARIAL SEAtL Renee Giampole, NotaryFPublic Penn Township, WestmorelandCounty My Commission EXpires Septemrbef25, 201 3

1~,.

2 CAW-1:0-2803

(I) I am Manager,,Regulatory Compliance and PlanityLicensing, in Nuclear Services, Westinghouse Electric-Comp'any LLC ("WeStinghou'se)and sysuch, I hae been*nspeifiilly delegated the function :of rev'iewing theproprietary information sought to be withheld fromfi public disclosu"re in connectionwith.inuclear power plant )licensingand nrile:makingproceeeidings, and am authorized to apply for its withholding:on behalf of Westinghouse' (2) 1 amf making this Affidaviitin conformaince with the :,provisions of iO:CFR Section 2390of the co~mniis ion's-regulat ions and in cij uCtin whfiithe Westinghouse Application for Withholding Proprietary Information from Public Disclosure 4companying thisý Affidavit.

(3)'. Ihavepersonai knowledge of the criteria and procedures utilized by Westinghouse in desig ating

ýinformation as a trade secret, privileged or as confidentialcommerciaLor0financial information.

(4)" Pursuant to the provisionsof paragraph (b)(4)*ofSection2.390 of the Commission's regulations, the fo!lowing~is*fumished *fr.,consjderatiponby the Commission in determining whether the information sought.to be with!hld from public disclo'sure shotld. be withheld' (i). Theiinformation sought tobie withheld f6rm, public disclosure is ownedafidrhs beeheld, in confideneeby'Westinghouse (ii) The information is ,ofa.type.custiomarily hebld in confidence by Westinghouse and not customarily disclosed to thepublic. Westinghouse has a rational basis fordetermining h~etypes of information customarily, held :'in confidencebyit and,binwthat connection, tutilizes a system. todetermine' when aid'whether to hold certaintypes of information in confidence. The ;applieati6 of that.system' aind the substance of that system constitute Westinghouse policyand provide the ration alib~sis: required; Under thatzsystemr information.is,'held. in confidence 'if it falls in one, ormore of several types, the release of which mightfresul in,the loss-of an existing or potential competitive:

advantage, as follows:

(a) The nf6rofiatin re'veals thedigtinguisiihgaspects ofa process,(or compone nt, structure, tool,:method, etc.)where preyention of its uo by any of

3 CAW-I 0-2803 Westinghoiuse's-competitors-witlhout license :from Weitin ghouse constitutes.a competitive economic-Aadvantageýo'er other comnpan ies.

.(b) It consists of supporting data, including test-data, relative toa process (or component, structure, tool,,method, etc.), tie application of which data secures a competitive economic advantage, e.g., by optimization or improved marketability.

(c) Its use by a competitor would reduce his expenditure:of resources or improve his competitive position in the design, maniufacture, shipment,:installation,-assurance

.of quality, or licensing-a similar product.

(d) ltureveals cost or price information, productioncapacities, budget levels, or commercial. strategies, of Westinghouse, its customers or suppliers.,

(e6) Itrreveals aspects ofpast,,present, or future Westinghouse oricustomer funded

-development plans'apd p.ograms-of potential commercial value to Westinghouse,

() It contains -patentable ideas,,for .whicihpatent-pr6tection maybe desirable.

There are sound policy-reasons:.behindthe Westinghouse system which include the following:-

(a) The useof such infdrmktion by Westingbous gires Westinghouse a competitive advantage over-its c6mpetitors. Itis, therefore, withheld from disclosure to protect the Westinghouse-competitive position.

.b) It is information thatismarketable in.many ways. The extent towhich such information is available to competitors diminishes the Westinghouse ability to.

sell products and services, involvingthe use of the information..

(c) Use by our completitor would pUt Westinghouse at a competitive disadvantage by reducing hisexpenditureof resources at ourexnpense.

PA 4 CAW-10-2803 (d)' Each -c mip-On:ent' f prpietary irinatioh pertinent to a paricular competitive advanrtage is potentially'as.valuabl6eas the total con'pietitive aidVaitage. If competitors acq uire *componentsobfproprietary informationi, any oniec0omponent-maybe thekey to theentire.puzzle,.thereby depriving Wesfingh6use of a competitive advantage.

(e): Unrestricted disclosure wouldjeopardize the position-of prominence of Westinghouse -inithe.wo0ld market, and thereby give a marketfadvantage to the competition of those countries.

(t) The Westinghouse caPacity to invest corporate assets in**iesearch anid:

developmenit depends upon the success inIobtaining and 4maintaining a compeiitiveadvantage.

(iii) The. information is being'transmitted to the Commission in .confidence andunder the provisiornes of 1 CFRSeion,2.39O; it is tobe received in confidence by ihe Commission.,

(iv) The'in'formation6rsoght to b&protected is:ntot.availabldeý n public- sources or available information hias not been.previously empioyed'.in.the same original mannerior method to the best of:ourjknowledgezand belief.

,(v) The proprietary information sought*tobe.withheld'in this submittal is that W hicis appropriateIly maked in LTR-SGMP- 0-50 P-Attachmento, Assessment o ftheEffect of' the Location ofthe Bott6m ofthe Expansion, Trnsitiono.,n.H*," dated April-,2'0010.

(Proprietary),- for:submittai to the'.Commission,!being transmitted by:Dominiin Nuclear.

Connecticut, Inc~letter and Application for Withholding Prbprietary .Informationi from Public Disclosure to the Dbocument Control Desk. The-proprietary information as, submifted for use by Westinghouse for Millstone.,Uniit 3.is expected to,be applicable to, other licensee submittals in support of implementing an alternate repair criterion, called n*,.that does ibt, require, an eddy current inspection and plugging of the tubes'belowa distance of 13.1 inches from the top of the tubesheetý

5 CAW-10-2803 This information is part.of that which Will: enable Westinghouse to:

(a) Provide supplemental,i.nformation related to thei location of the bottom of he hydrau!iic'expansion transition from .the top of ihe tubesheetiand' its 'impacto'n Ithe alternate repair criterion, designated'as H*, for a portion of the tubes. within, the:

tubesheet of the Millstone Ufiit 3 steam-generatorsý (b) Assist-the customer in'6btainingNRC approval of the Technical Specification.

changes associated with the alternate repair criterion.

Furthertrhis information has substantiM commercial valueas follows:

(a) Wesiinghouseplans to.sell the~use of similar information to its customers for the purposes ofmeftingNRC, requiremehtis f6r liciensing documentation.

(b) Westingh6use can sel stipport and defe§nse of the: technology to its cistomers' in

• the licensing-process.,

Public disclosure~of this proproietary information ýis likely~to cause substantial, harm to the competitive: position .ofWestingho.use becauseit wQuld.enhance the ability of competitors:to provide simfilar c9lculation, evaluation and licensing~defense services-for c6mmercial ptwerreacto ýwithout comm ensurate expenges. Also, public:disclosure of the informatibn .would enable; others tb use :the infdration to:meet NRC requirements f6r licensing documentation Without purcihasinhg the 'right6to use the information.

The development ofthe technology described in part by the information isthe:result-of applying the results of many years ,ofexperience in an intensive Westinghouse .effort and

-the expenditure of a.considerable sum of money.

In order f6r competitors of Westinghouse to duplicate this information, similar technical programs would -have to be performied and a significant manpower effort, having: the requisite talent and experience, would haveltobe:expended.

Further the deponent sayeth not,

4 PROPRIETARY INFORMATION NOTICE.

Transmitted'heieewith aie proprietary and/or non-propfietary versions of documents furnished to the NRC in connection with requests for generic and/or plant-specific review and approval.

In order'to'conform to the requirements of I0CFR 2.390 of the Coimmission'S regulations concerning the protection of Proprietary information.so submitted to the NRC, the in formation which is proprietary in the proprietary versionsis contained within brackets, and where the proprietary information has been deleted in the non-;proprietary versions, only the brackets remain (the information that was contained within the brackets in the proprietary versions having been deleted). Thetjustififcation .for claiming the information so desighnted.as proprietary is indicatedin both. versions by means of lower case letters (a) through, (f) being located as a superscript immediately following the brackets enclosing each item of information identified as proprietary or-in the margin opposite such.ififormation. These lower~case letters refer to the types of information Westinghouse cust6marily holds in confidence idenhtified in Sections (4)(ii)(a)

,through (4)(ii),)D qf the affidavitaccompanying this transmritai pursuant tot 10 CFR "2 390(b)(.l).

COPYRIGHT .NOTICE The reportstransmitted herewith each bear, a. Westinghuise 'cpyrightnotice. The'NRC is permittedto make thle n.umert of copies of the ihformnation contained in these reports which are necessary for its internal use in connection with generic and:plant-specific reviewsand approvals as well as the issuance, denial, amendment,transfer,renewal, modification, suspension, revcication,-or violation of a license; Permit, orderf,'or regulati6n subjectt6 the requiriiemen!ts of1:0 CFRC2.390 gagingarestricti6hs on public disclosure to theextent sutch'information has been identified as proprietary by Westinghouse,. copyright protection notwithstanding. With respect to the non-proprietary versions 6f these, reports,, the NRC: is perrnitted'to-makethe numberof copies beyond'ihose necessary for its internal Usewhich are necessary in order to have one copy available for public viewing :n'the ,appropriate docket files in the public dOcument room in. Washington', DC and in local public document rooms as may be, required by NRC regulations if the number of'copies submitted isinsufficient for this purpose. Copiesý made by the NRC must include thecopyright notice in all instances and the proprietary notice if the original Was identified as proprietary.

9 Dominion Nuclear Ctnnecticut, Incd.

Letter for Transmittal to4he NRC.

The following paragraphs should be included in your letter to the NPC:

Enclosed are:

l: 1 copy of LTR-SGMP-10-50. PAttachment, "Assessment of'the Effect of the Location of-the Bottom of the Expansion Transition onH*," dated April 20,10 (Proprietary)

,2-1 copy of LTR-SGMP'10-50 NP:"Attachment;`"Assessment of the, Effect of thelocation.of the Bottom of theExpanksion Transition on H*" dated April 2010 i(Non-Proprietayry)

Alsoenclosed is Westinghouse authori zation letter CAW-10-2803 with- accompanyiig affidavit, Proprietary Information Notice, and Copyright:Notice.

As Item 1 contains information proprietary to Westinghouse ElectricCompafiy LLC, it is suppcrted'by a affidavit signed byWestihghouse,,the owner of the information. The affidavit sets forth the. basison which the information may be witfiheld from public disclosure by-the Commission-and addresses with specificity the considerations listed in paragraph:(b) (4) of Section 2.390 of the Commission's regulations.

Accordingly, it is respectfhlly requested thaitthe information which is proprietary to Westinghouse be withield from public'discl6sire in accordahnce.with 10 CFR Section 2.390 of the.Commission's regulations.

Correspondence with respect to the:copyright or proprietary aspects of theitems listed above, or'the

• supporting Westinghouse ,iffidavit should6refrencer CAW 2803 and.should be addressed to K. A.'Gresham,,Mapnager, Regulatory Co'mpýliance' and Plant Licensing,'Westinghouse Electric Company

,LLC, P.O.,Box.355, Pittsburgh, -Pennsylvaia15230-0355.