ML061240326
| ML061240326 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/30/2006 |
| From: | Ayres D, Thomas Magee, Morgan E, Nelson P Westinghouse |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC MC8850, TAC MC8851 LTR-CDME-06-27-NP, Rev 0 | |
| Download: ML061240326 (36) | |
Text
Enclosure (5)Nonproprietary copy of the response document, Westinghouse Document NLImber LTR-CDME-06-27-NP, Revision 0, dated April 2006, titled "Responses to NRC Request for Additional Information on License Amendment Request for Proposed Technical Specification Change Regarding Repair Criteria and Inspection Depth for Steam Generator Tubes within the Tubesheet Region Southern California Edison San Onofre Nuclear Generating Station, Units 2 and 3, Docket Nos. 50-361 and 50-362."
WESTINGHOUSE NON-PROPRIETARY CLASS 3 (TAC NOs. MC8850 and MC8851)Responses to NRC Request for Additional Information on License Amendment Request for Proposed Technical Specification Change Regarding Repair Criteria and Inspection Depth for Steam Generator Tubes within the Tubesheet Region Southern California Edison San Onofre Nuclear Generating Station, Units 2 and 3 Docket Nos. 50-361 and 50-362 LTR-CDME-06-27-NP, Revision 0 April 2006 Prepared by: Reviewed by: Approved by: DJA and PRN (*)David Ayres, Consultant Peter Nelson, Fellow Engineer Chemistry, Diagnostics
& Materials Engineering TPM (*)Thomas Magee, Principal Engineer Chemistry, Diagnostics
& Materials Engineering EPM(*)Earl Morgan, Manager Chemistry, Diagnostics
& Materials Engineering
- Electronically Approved Records Are Authenticated in the Electronic Document Management System.Westinghouse Electric Company LLC P.O. Box 355 Pittsburgh, PA 15230-0355
© 2006 Westinghouse Electric Company LLC All Rights Reserved ii TABLE OF CONTENTS TABLE OF CONTENTS ........................................
ii LIST OF TABLES .........................................
iii LIST OF FIGURES ........................................
iTV DEFINITIONS
...........................................
i.1.0 Introduction
......................................... .I l.1 Background
..........................................
I 1.2 Summary .........................................
I].3 Quality Assurance
........................................
1 2.0 Responses to Requests for Additional Information
.........................................
- 2.1 RA I #1 .........................................
.2.1.1 Response to RAI# 1 .........................................
- '-2.2 RAI #2 ..........................................
4 2.2.1 Response to RAI #2 ........................................
i 2.3 RAI #3 ...........................
..4 2.3.1 Response to RAI #3 ...........................
5 2.4 RAI #4 ...........................
14 2.4.1 Response to RAI #4 ..........................
14 2.5 RAI #5 ..........................
- 14 2.5.1 Response to RAI #5 ..........................
15 2.6 RAI #6 ...........................
1';2.6.1 Response to RAI #6 ..........................
16 ,.7 RAI #7 ...........................
16 2.7.1 Response to RAI #7 ..........................
16 2.8 RAI #8 ...........................
1.2.8.1 Response to RAI #8 ..........................
16 3.0 References
..........................
18 Table of Contents April 2006 LTR-CDME-06-27-NP Revision 0 iii LIST OF TABLES Table 1: Summary of Data of Figure 1 .....................................................................
3 Table 2: Rough Bore 'First Slip' Pullout Test Data (Room Temperature, Ambient Internal Pressure)
.............................................................
7 Table 3: Sum of the Forces for the WCAP 16208-P, Rev. 1 Hot Leg Case, P=2560 psid, T=590'F For SONGS Units 2 and 3 ............................................................
9 Table 4: Sum of the Forces for the WCAP 16208-P, Rev. 1, Supplement 1, Cold Leg Case, P=2560 psid, T=475 0 F For SONGS Units 2 and 3 ..........................................................
10 Table 5: Interpolated Depth in Tubesheet Length and Inspection Length including Dilation and NDE Uncertainty
....................................................................
12 Table 6: Reference 1 and Recalculated Inspection Lengths ..........................................................
12 Table 7: Table 2-1 from WCAP-16208-P, Revision 1: Leakage Based Inspection Length Including Tubesheet Deflection and NDE Corrections (Amended for SONGS Units 2 and 3) ...... 12 Table 8: Table 6-15 from WCAP-16208-P, Revision 1: Inspection Length Based on Leakage (Amended for SONGS Unit 2 and 3) ............................................................
13 Table 9: Executive Summary Table from WCAP-16208-P, Revision I (Amended for SONGS Unit 2 and 3) ....................................................................
13 Table 10: Executive Summary and Table 4-1 from WCAP-16208-P, Revision 1, Supplement 1: Recommended Hot Leg and Cold Leg Inspection Lengths for SONGS 2 and 3 .............
13 List of Tables LTR-C'DME-06-27-NP April 2006 Revision 0 iv LIST OF FIGURES Figure 1: Tube to Tubesheet Joint Leak Rate Data for Hot Leg, 5900F and AiP = 2560 psid ...................
3 Figure 2: First Slip Pullout Force for 48 rnil Wall Rough Bore Tests .......................................................
8 List of Figures LTR-C DME-06-27-NP April 2006 Revision 0 v DEFINITIONS ARC -Alternate repair criteria are approvals by NRC to utilize specific criteria for repair decisions based on detection of flaws.AVT -All Volatile Treatment.
BET -Bottom of the explansion transition.
BTA -Bore Trepanning Association process for machine boring. A process improvement employed for tubesheet drilling.
Not applicable to SONGS Units 2 and 3.Collar -Tubesheet mockups were fabricated from tubesheet bar stock material SA-508, Class 3. The machined bar stock in which a tube was explosively expanded was referred to in this project as a collar.C* -The CE design explansion joint inspection distance.EDM -Electrical discharge machining.
EOC -End of the operating cycle.Explan fion -Explosive expansion of tubing into a Combustion Engineering steam generator tubesheet.
F* -The Westinghouse design rolled joint inspection distance.]n*c,e Joint -The tube and tubesheet contact surface area created by the explansion process.H* -The Westinghouse design hydraulic expansion joint inspection distance.Leakage criteria -The generic Combustion Engineering design technical specifications LCO for accident induced leakage value is 0.5 gpm per steam generator.
The leak limit is reduced to one-fifth (i.e. 0.1 gpm)to provide margin for leaks from other potential degradation types. The criterion conservatively assumes that the leakage is from 100% of the tubes in the steam generator that have throughwall circumferentially oriented flaws present at the threshold length below the hot leg BET (Bottom of the Explansion Transition).
LCO -Technical specifications limiting condition for operation.
Definitions April 2006 LTR-C'DME-06-27-NP Revision 0 vi Maximum load -The largest force encountered while pulling the tube out of the tubesheet.
MDM -Metal Disintegration Machining.
NODP -Normal operating differential pressure = RCS pressure minus SG pressure at normal full power operating conditions.
Pulloul force -The force required to move the tube relative to the tubesheet.
I] acle POD -Probability of detection based on the ability of an NDE technique to indicate the presence of a flaw.RAI -Request for additional informnation.
Rough bore -The machined surface on the inside diameter of each laboratory specimen rough bore collar was drilled on a lathe to a surface roughness not greater than 250 micro-inches (AA) to mockup the gun-drilled tubesheet hole surface. Applicable to SONGS Units 2 and 3.SLB or MSLB -The design basis event known as main steam line break.STD -The Science and Technology Division of Westinghouse.
Smooth Bore -The machined surface on the inside diameter of each laboratory specimen smooth bore collar was drilled on a lathe to a surface roughness not greater than 250 micro-inches (AA) and then reamed to increase smoothness to mockup the BTA process tubesheet hole surface. Not applicable to SONGS Units 2 and 3.Taper- The theoretically incomplete contact near the top of the joint just below the explansion transition.
The W" topical report increased the threshold length to account for an approximately 0.7" taper.Threshold length -The tube to tubesheet joint length below the BET that provides a sufficient contact force tc preclude pullout at 3NODP and leakage at SLB pressures.
TTS -'Top of the tubesheet.
W* -The Westinghouse design explosive expansion joint inspection distance.Definitions LTR-CDME-06-27-NP April 2006 Revision 0 I 1.0 Introduction
1.1 Background
The Westinghouse Owner's Group Cut program provided recommended tubesheet region inspection lengths, for plants with Combustion Engineering supplied steam generators with explosive expansions.
The technical basis for changes that define the depth of the required tube inspections and plugging criteria within ilhe tubesheet, with the depth of inspection defined as "C*" ("C-star"), was initially documented in Westinghouse topical report WCAP-16208-P, Revision 0, "NDE (Non-Destructive Examination)
Inspection Length for CE (Combustion Engineering)
Steam Generator Tubesheet Region Explosive Expansions," dated October 2004. In a letter dated December 16, 2004 (ML043510406), the U.S. Nuclear Regula:ory Commission (NRC) staff requested additional information from Florida Power and Light (FPL) atbout their C* amendment application for St. Lucie Unit 2. FPL's response to this request was issued March 31, 2005 (ML050960517), and Revision 1 of WCAP-16208-P was subsequently issued in May 2005 (ML051520420).
By letter dated November 3, 2005, Southern California Edison (SCE)submitted an application to change the San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 technical specifications (TS) related to steam generator tube inspection.
The SCE application referenced WCAP-16208, Revision 1, and submitted a Supplement 1 (Reference 1), which applies the C*methodology in the cold leg of the SONGS Units 2 and 3 steam generators.
In a letter dated March 23, 2006 (Reference 2), the NRC staff requested additional information (RAIs) to support their review.. This document provides responses to the NRC staff RAIs.1.2 Summary A fundamental objective of WCAP-16208-P, Revision I was to establish a leakage based inspection depth to ensure that the total predicted leakage from the tubesheet at SONGS Units 2 and 3 was no more than 0.1: gpm/SG assuming 9,300 hot leg side tube to tubesheet joints in service and leaking. On a per tube basis, this translates to a leak rate of 1.08x10 5 gpm/tube .The determination of the inspection length for the cold leg side used the same technical basis and assumed tube count of 9300 tube to tubesheet joints. The cumulative leak rate from the hot leg and cold leg sides would then be 0.2 gpm/SG. The primary to secondary leakage rate assumed in the current accident analyses for SONGS Units 2 and 3 is 0.5 gpni/SG (Reference 3). This response to NRC staff RAI's included recalculation using "first slip" rather t han "maximum load" pullout data. A recalculated minimum required inspection depth to maintain this per tube and per SG leakage rate is provided in this document.1.3 Quality Assurance The work that is presented in this document was completed and reviewed under the requirements of the Westinghouse Quality Assurance Program (Reference 4).Introduction April 2006 LTR-C'DME-06-27-NP Revision 0 2.0 Responses to Requests for Additional Information 2.1 )AI #1 Please confirm that your operating parameters (e.g., temperature, pressure, etc.) will always be conservatively bounded by the conditions for which the hot-leg and cold-leg C* distances were determined in WCAP-16208-P, Revision I (including Supplement 1). If the conditions will not always be bounded, what controls are in place to ensure an adequate depth of inspection in the tubesheet?
For example, please confirm that the hot-leg temperature at SONGS, Units 2 and 3, is greater than that assumed (600 degrees Fahrenheit) in the tubesheet deflection analyses and in determining the increase in contact pressure as a result of differential thermal expansion between the tube and the tubesheet.
If the hot-leg temperature in either unit is lower than 600 degrees, please discuss the effect on the C* distance.2.1.1 Response to RAI #1 The requested review of C* analysis assumptions and SONGS Units 2 and 3 operating parameters was completed.
All SONGS Units 2 and 3 operating parameters were determined to always be conservatively bounded by the conditions for which the hot-leg and cold-leg C* distances were determined in WCAP-16208-P, Revision 1 (including Supplement 1), with one exception (the normal operating hot leg temperature).
The normal operating hot leg temperature at SONGS Units 2.ard 3 is conservatively bounded by 590'F, so the generic C* analysis (that uses 600'F) is modified to consider the SONGS-specific temperature.
In WCAP16208-P, Rev. 1, an approach to determine the change in leakage due to temperature and pressure changes was developed.
The approach]atc.e Using the plant specific lower bound normal operation temperature of 590'F for the hot leg, and the generic MSLB pressure of 2560 psi, the normalized leak rate vs. contact length of Figure 4-4 of W'CAP-16208-P, Rev. 1 is adjusted for the hot leg in Figure 1.Responses to RAIs LTR-C'DME-06-27-NP April 2006 Revision 0 3 Fiigure 1: Tube to Tubesheet Joint Leak Rate Data for Hot Leg, 5900 F and AP = 2560 psid Table 1: Summary of Data of Figure 1 Total Leakage per Unadjusted Case Tube Leakage Length Hot Leg, AP=2560psi, T=590'F 1.08E-5 gpm 6.59" The upper level 95% confidence basis hot leg joint length that meets the leak criteria of 1.08E-5 grim/tube joint for the SONGS Units 2 and 3 is 6.57inches unadjusted for temperature, pressure, and tubesheet bow effects. This WCAP 16208 joint length of 6.57 inches was determined for the generic MSLB event at a pressure of 2560 psi and 600TF. The hot leg value of the unadjusted leakage length for the SONGS 2 and 3 specific value of 590TF provided in Table 1 is 6.59". Further recalculation will be continued in the response to RAI #3.Responses to RAIs LTR-C'DME-06-27-NP April 2006 Revision 0 4 2.2 RAI #2 The SONGS, Units 2 and 3, currently allow the installation of leak-tight sleeves according to Asea B:rown Boveri/Combustion Engineering, Inc. (ABB/CE) Topical Report CEN-630-P, Revision 2.The proposed revision of TS 5.5.2.1 .h excludes from inspection the portions of the tube below the C* distance in the tubesheet.
Since sleeves could extend into the tubesheet below the C* distance, th5 proposed TS would no longer require the sleeve or tube to be inspected in this region. Sleeves were not addressed in the testing and analysis used to justify excluding part of the tube from inspection (WCAP-16208-P, Revision 1, including Supplement 1). What plans do you have to ensure the lower ends of sleeves (i.e., those within the tubesheet below the C* distance) will be in spected, including the pressure-retaining portion of the parent tube in contact with the sleeve, the sleeve-to-tube weld, and the pressure retaining portion of the sleeve? Please discuss your plans to modify your TS to address this issue. Consider, for example, the following wording: "For a tube with no portion of a sleeve extending below (a) 10.4 inches from the bottom of the hot-leg expansion transition or the top of the tubesheet (whichever is lower) or (b) 10.7 inches from the bcttom of the cold-leg expansion transition or the top of the tubesheet (whichever is lower), a tube in:;pection means an inspection of the steam generator tube from 10.4 inches below the bottom of the: hot-leg expansion transition or top of the tubesheet (whichever is lower) completely around the U-bend to 10.7-inches below the bottom of the cold-leg expansion transition or top of the tubesheet (whichever is lower)."For all other tubes, a tube inspection means an inspection from the bottom of the sleeve completely around the U-bend to either (a) 10.4 inches below the bottom of the hot-leg expansion transition or top of the tubesheet (whichever is lower) or (b) 10.7 inches below the bottom of the cold-leg expansion transition or top of the tubesheet (whichever is lower), as appropriate." 2.2.1 Response to RAI #2 The SCE Technical Specification (TS) Change Request Supplement will incorporate the wording suggested by the NRC Staff.2.5 RAI #3 It is the NRC staff's understanding that load at first slip, rather than maximum load, was reported and plotted in Figure 5-1 of WCAP-16208-P, Revision 1. If the load at first slip was not used in all cases, please discuss the effect on the required inspection distance if the load at first slip was used. In addition, if the load at first slip was not used in Table 6-8 of WCAP-16208-P, Revision 1 ("Burst Based Inspection Length"), please provide Table 6-8 values to confirm the 10.4 inch (hot leg) and 10.7 inch (cold leg) proposed inspection distances are bounded when the most limiting specimen is evaluated using load at first slip. In addition, please discuss the effect on the leakage-bas;ed inspection distance (Tables 6-9 and 6-15). If the leakage-based inspection length increased, discuss your plans to modify your TS accordingly.
Responses to RAIs April 2006 LTR-CDME-06-27-NP Revision 0 p1 5 2.3.1 Response to RAI #3 The pullout load data that was used in WCAP-16208-P, Revision 1 was taken from Reference
- 5. A review of the Reference 5 data determined that 'maximum load' data was used. Thus, with the exception of the pressurized data (which was not used in the regression analysis), the data that is plotted in Figures 5-1 through 5-3 of WCAP-16208-P, Rev.1 is based on the 'maximum load'ercountered during each pullout test.The leakage-limited inspection depth provided in WCAP-16208-P, Revision I uses the pdllout force to assess the contact pressure of the joint, which in turn is used to provide a tubesheet hole dilation adjustment to the depth at which the leak rate criteria is met. For this purpose, a 'first slip' criterion provides the relevant pullout force. Reference 6 uses a definition that [] a"e This length is understood to be applicable after gripper slippage had been accounted for. This criterion eliminates any bias associated with the 'first move' criteria.The rough bore pullout data provided in Table 5-2 of WCAP-16208-P, Revision I was obtained di rectly from Tables 4-2 and 4-3 of Reference
- 5. Re-examination of the Table 4-2 data showed that only those tests in which a leak test was performed were included in the table (compare with Table 3-3 of the Reference 5 report). Appendix D of the Reference 5 report lists all the Boston Edison samples that were pullout tested. In the response to this RAI, all of the Boston Edison pullout tests ares considered, not just those that were leak tested.In Reference 5, the Boston Edison pullout tests and the Sample 20 and 21 collar samples were performed with the load cell test rig shown in Figure 3.11 of the report. This rig was attached to the tube by means of a gripper. [I ace The pullout tests conducted in Windsor used fittings that were welded to the sample. These fittings had threaded ends that fit into threaded receptacles on the tensile tester. It was assumed that there was no gripper slippage in the tests conducted at the Windsor facilities.
TE.ble 2 provides all of the room temperature, ambient pressure pullout data from Reference 5, using the 'first slip' criteria.
The data in Table 2 has been scaled in the same manner as described in WCAP-16208, Section 5.3. In all cases, 'first slip' forces were less than 'maximum load' forces.Four of the samples exceeded the yield strength of the tubing material at the 'first slip' point.Another three samples exceeded the yield strength of the tubing material before the 'first slip' point had been reached, but was below the yield strength of the tubing at the 'first slip' point. The actual joint lengths are recorded in the table.Figure 2 presents a plot of the Table 2 data. Data that had exceeded the yield strength of the tube is plotted separately and was not included in the regression analysis.
The lower 95% prediction bound is also included.Responses to RAIs April 2006 LTR-C'DME-06-27-NP Revision 0 6 Fcrce is distributed over an increment of the joint interface surface. An axial increment of 0.25 inches is used in this analysis as in WCAP 16208-P, Rev.l. The force due to RCS pressure acts on an incremental area on the inside diameter of the tube. The force is transmitted to the outside diameter of the tube and acts on the inside diameter of the tubesheet hole. The tubesheet and tube fo ces must be equal in equilibrium or steady state condition.
The RCS pressure and differential thermal forces are adjusted for the bounding hot leg temperature (590 0 F) in Table 3 and the bounding cold leg case (475 0 F) in Table 4. The C* inspection length (sum of the forces) results developed from the use the first slip pull out force of Figure 2 and the hot leg joint lengths from Figure I and the cold leg joint length from Section 3.2.4 of Reference 1, are provided in Tables 3 (hot leg) and 4 (cold leg) with a summary of results in Table 5.The responses to these RAIs do not change the conclusion provided in Section 6.3 of WCAP-16208-P, Revision 1, that the leak-based inspection lengths bound the burst-based inspection lengths including the limiting specimen first slip case in which the burst based inspection length increases les.s than 1" greater than the WCAP-16208-P, Revision 1, Table 6-8 value of 2.6".This Technical Specification Change Supplement incorporates the recalculated inspection lengths in Table 5. Table 6 shows the previous inspection lengths in Reference 1, and the inspection lengths recalculated for this report. Table 2-1, Table 6-15 and the Executive Summary Table of WCAP-16208-P, Revision I are thus amended as shown in Tables 7, 8, and 9 respectively.
Table 4-1 and the Executive Summary Table of WCAP-16208-P, Revision 1, Supplement I are also amended as shDwn in Table 10.Responses to RAIs LTR-C'DME-06-27-NP April 2006 Revision 0 7 Table 2: Rough Bore 'First Slip' Pullout Test Data (Room Temperature, Ambient Internal Pressure)0.25" First Slip As-Built Load(lbf)Test Engaged (adj for Tube ID Lab Length(in.)
grip slip) Note I=-I__==_I H I--==I-I=I I _abc Responses to RAls LTR-C'DME-06-27-NP April 2006 Revision 0 81 Figure 2: First Slip Pullout Force for 48 mil Wall Rough Bore Tests a,bc I Responses to RAIs LTR-CDME-06-27-NP April 2006 Revision 0 9 Table 3: Sum of the Forces for the WCAP 16208-P, Rev.1 Hot Leg Case, P=2560 psid, Th590'F For SONGS Units 2 and 3 RCS Pressure and Diff.TS Joint Thermal Initial Dilation Net Equiv. Cum.Depth in Axial Axial Axial Axial Axial Net I No-Dilate No-Dilate Tubesheet Force Force Force Force Force Intial Length Length , (in) (IbfI) (Ibf) (bf) (Ibf) (Ibf) Ratio (in) (in)Responses to RAIs LTR-CDME-06-27-NP April 2006 Revision 0 to Table 3 (continued)
RCS Pressure and Diff.Depth in TS Joint Thermal Initial Dilation Net Equiv. Cum.Tubesheet Axial Axial Axial Axial Axial Net / No-Dilate No-Dilate (in) Force Force Force Force Force Intial Length Length_lb (lbf) (Ibf) (Ibf) (IbfI) Ratio (in) (in) ab.c Table 4: Sum of the Forces for the WCAP 16208-P, Rev.I, Supplement I Cold Leg Case, P=2560 psid, T=4751F For SONGS Units 2 and 3 RCS Pressure and Diff.Depth in TS Joint Thermal Initial Dilation Net Equiv. Cum.Tubesheet Axial Axial Axial Axial Axial Net / No-Dilate No-Dilate (in) Force Force Force Force Force Intial Length Length bc__ (Ibf) (lbf) (lbf) (Ibi) (lbf) Ratio (in) (in)7 Respo:ases to RAIs LTR-CDME-06-27-NP April 2006 Revision 0 I1 Table 4 (continued)
RCS Pressure and Diff.Depth in TS Joint Thermal Initial Dilation Net Equiv. Cum.Tubes heet Axial Axial Axial Axial Axial Net / No-Dilate No-Dilate (in) Force Force Force Force Force Intial Length Length (_bo (Ibf) (Ibi) (lbf) (Ibf) Ratio (in) (in)ab,=-=== =-_ _ == __=== _-== .._-== _-=_=_ == == =-=_-== _ _.==== _= == __=-_ __ __ __ ___Responses to RAIs LTR-C'DME-06-27-NP April 2006 Revision 0 12 Table 5: Interpolated Depth in Tubesheet Length and Inspection Length Including Dilation and NDE Uncertainty Case Cn.N-iaeNDE Inspection LCue. No-Dilate Dcpth in Uncertainty, Length, (in)Tubeshect, (in) (in)abc Table 6: Reference 1 and Recalculated Inspection Lengths Previous Inspection Recalculated Length in Reference 1, Inspection Length, Plant inches inches abc ri I _-U I .L_Table 7: Table 2-1 from WCAP-16208-P, Revision 1: Leakage Based Inspection Length Including Tubesheet Deflection and NDE Corrections (Amended for SONGS Units 2 and 3)Plant Leak Rate Based Leak Rate Based Inspection Length Inspection Length Adjusted for TS Adjusted for TS Dilation Dilation and NDE (inches) (inches) -abc FL.1i_= I Responses to RAIs LTR-C(DME-06-27-NP April 2006 Revision 0 13 Table 8: Table 6-15 from WCAP-16208-P, Revision 1: Inspection Length Based on Leakage (Amended for SONGS Unit 2 and 3)Plant Burst Interpolated Leak Rate Based Leak Rate Based Inspection Uncorrected Based Inspection Length Joint Length Inspection Length Corrected that Meets Length Corrected for for Dilation Leakage Corrected for Dilation and and NDE Criteria Dilation NDE (in.) (inches) (in.) (in.)rt LL--j, Table 9: Executive Summary Table from WCAP-16208-P, Revision 1 (Amended for SONGS Unit 2 and 3)Plant Leak Rate Based Inspection Length Corrected for Dilation and NDE (in.)C .a,b,c]1-Table 10: Executive Summary and Table 4-1 from WCAP-16208-P, Revision 1, Supplement 1: Recommended Hot Leg and Cold Leg Inspection Lengths for SONGS 2 and 3 Cold Leg Hot Leg Inspection Inspection Leak Rate Criterion Number of Joints Length Length MSLI1 Case (gpm)Assumed to be Corrected for Corrected fcr Leaking Dilation and Dilation and NDE NDE a.bc__(in.) (in.) -I I I. J _ _ _ I Responses to RAIs LTR-CDME-06-27-NP April 2006 Revision 0 14 2.6 RAI #4 Please discuss your plans to revise your TS to include the reporting requirements listed below: (a.) Number of total indications, location of each indication, orientation of each indication, size of each indication, and whether the indications are initiated from the inside or outside surface.(b) The cumulative number of indications detected in the tubesheet region as a function of elevation within the tubesheet.(c) Projected end-of-cycle (EOC) accident-induced leakage from tubesheet indications.
This leakage shall be combined with the postulated EOC accident-induced leakage from all other sources. If the preliminary estimated total projected EOC accident-induced leakage from all sources exceeds the leakage limit, the NRC staff shall be notified prior to unit restart.2.4.1 Response to RAI #4 For the above listed reporting requirements (a) and (b), SCE has proposed equivalent reporting requirements in Reference (3).SCE does not think there is value in the above listed reporting requirement (c), for this particular Technical Specification Change Request. Note that C* analysis assumptions and plugging criteria are significantly different from analysis assumptions and plugging criteria for other tubesheet region alternate repair criteria for other designs. SCE does not plan to supplement the Technical Specification Change Request to add requested reporting requirement (c) for the following reasons: 4. Within the inspected region in the hot leg tubesheet, all detected indications above the C*inspection depth are "plugged upon detection".
These indications are not a contributing source in projection of accident induced leakage for the next cycle of operation.
- 5. Within the inspected region in the cold leg tubesheet all detected indications are "plugged upon detection".
These indications are not a contributing source in projection of accident induced leakage for the next cycle of operation.
- 6. Within the uninspected region in the hot leg and cold leg tubesheets, the projection of accident induced leakage for the next cycle of operation is an essentially unchanging, "worst: case" analysis assumption.
It is 0.1 gallons per minute (gpm) for the hot leg tubesheet, and 0.1 gpm for the cold leg. This unchanging worst case value is the C* analysis assumption that ALL tubes are assumed to be degraded by 100% throughwall 360 degree circumferential cracks, all located immediately below the inspected length of the tube. Note that all detected indications below the C* inspection depth in the hot leg tubesheet that are left inservice are part of the analysis assumption for the uninspected region.2.5 RAI #5 The proposed revision of TS 5.5.2.11.f.1.f provides exceptions, based on the C* distance, to applying the tube Repair Limit within the hot-leg tubesheet for tubes that have not been repaired and Responses to RAIs April 2006 LTR-CDME-06-27-NP Revision 0 15 tubes that have been repaired (sleeved).
These exceptions are not included for the cold-leg tubesheet.
It is, therefore, the NRC staff's understanding that any tube degradation detected below the bottom of the cold-leg expansion transition or cold-leg top-of-tubesheet, whichever is higher, shall be removed from service or repaired on detection.
Please confirm or correct the staff's understanding.
Please provide a justification for the difference in plugging/repair requirements for degradation in the hot-leg and cold-leg tubesheet in your proposed TS, or discuss your plans for modifying the proposed TS for consistency between the hot- and cold-leg tubesheet repair requirements.
2.5.1 Response to RAI #5 The staffs understanding is correct. For the cold leg, SCE is not requesting an alternate repair criteria because inspection results indicate it is not needed. The justification for the difference in plugging /repair requirements for degradation in the cold leg tubesheet is that an alternate repair criteria appears unnecessary, and thus is not being proposed by SCE.2.6 RAI #6 According to Enclosure 3 to your November 3, 2005 submittal, the primary-to-secondary accident-induced leakage limit for SONGS Units 2 and 3 is 0.5 gpm per SG. For Unit 3, this limit is the same as the limiting condition for operation in your TS LCO 3.4.13.d since no sleeves are installed.
For U:ait 2, LCO 3.4.13.d specifies a maximum operational leakage rate of 0.1 gpm per SG since sleeves are installed.
Since the operational leakage limit is equal to the accident-induced leakage limit, please address the following for Unit 3: a. During a steamline break the differential pressure across the tubes is greater than the differential pressure during normal operation.
As a result, the primary-to-secondary leakage may be greater dcling a steamline break than during normal operation.
Since you could be operating with leakage as high as your normal operating leakage limit (0.5 gpm), the amount of leakage during a steamline break (or other postulated accidents) could be greater than that assumed in your accident analyses.
If so, please discuss what controls are in place to ensure that you do not exceed your accident-induced leakage limit simply as a result of normal operating leakage.b. As part of the C* amendment, you will be assuming there is 0.2 gpm accident-induced primary-to.-
se~ondary leakage as a result of flaws within the tubesheet region. In addition, you may have accident-induced leakage from other sources such as sleeves or other degradation.
This latter amount of leakage will need to be limited to 0.3 gpm to ensure you do not exceed your accident-induced leakage limits in your updated final safety analysis report (UFSAR). Since the source of any normal operating leakage is not known (i.e., it could be from sources other than the tubesheet or sleeves or other defects assumed to leak in your operational assessment) and it could be as high as your TS limit of 0.5 gpm (or even higher during some postulated accidents due to the increased differential pressure), it is not clear that you will be able to stay within your accident-induced leakage limits unless you change your TS normal operating leakage or your UFSAR accident analysis leakage limit. Please discuss whether you will be able to stay within your accident-induced leakage limits and your proposed C* inspection requirements.
Responses to RAIs April 2006 LTR-CDME-06-27-NP Revision 0 15 2.6.1 Response to RAI #6 SCE has proposed a reduction of the Unit 3 operational leakage limit in Reference
- 3. Reference 3 provides consistency between Units 2 and 3.2.7 RAI #7 Do all of the tubes in your SGs have adequate expansion in the tubesheet to meet the leakage and pullout criteria?
That is, are all of the tubes nominally expanded for the full depth of the tubesheet?
If any tubes are not nominally expanded for the full depth of the tubesheet, have you verified that the expansion length is adequate to ensure structural and leakage integrity consistent with the C*approach?
For those tubes which may not have adequate expansion lengths, discuss how you will ensure structural and leakage integrity for these tubes (e.g., inspection of the tube-to-tubesheet weld). Also, discuss whether any changes are needed to your TS to address this issue.2.7.1 Response to RAI #7 All in service tubes in the SONGS Units 2 and 3 steam generators have adequate expansion in the tubesheet to meet the leakage and pullout criteria.
SCE has determined, by special-purpose eddy current data analysis, that all of the in service tubes are nominally expanded for the full depth of the tubesheet.
No changes are needed to SCE's existing Technical Specification Change Request.2.8 lAl #8 Please describe the expected condition of the tube-to-tubesheet crevice, such as the amount of corrosion product and sludge at the top of the tubesheet.
Discuss the effects of these conditions on tube-to-tubesheet contact pressure and the potential for leakage.2.&.1 Response to RAI #8 The expected condition of the SONGS Units 2 and 3 stream generator crevices are similar to or exceed the extent of corrosion products that may have been present in the C* program test specimens.
Thus, the C* program test sample tube-to-tubesheet contact pressure and leakage performance are bounding.
This expectation is based on the following:
- c. During refueling outages, the top-of-tubesheet is exposed to an oxygen atmosphere for several days during the steam generator secondary side inspection/maintenance activities.
This is similar to conditions experienced with the C* test specimens.
It is expected that these conditions would add to the probability that corrosion products develop in the tube-to -tubesheet crevice, similar to the C* program test samples.d. Steam generator secondary side chemical cleaning was performed in 1997 at SONGS Units 2 and 3. This cleaning was performed on the full height of the tube bundle. The results of the cleaning and subsequent sludge lancing indicate significant reduction in the inventory of sludge-forming corrosion products.
The results of subsequent periodic sludge lancing indicate that formation of sludge is significantly reduced (from the pre-cleaning period), but Responses to RAIs April 2006 LTR-CDME-06-27-NP Revision 0 17 is an ongoing process. For example, a total of 149 pounds of undried sludge was removed from both of the Unit 3 steam generators in October 2004. It is expected that these condition:;
would add to the probability that corrosion products develop in the tube-to-tubesheet crevice, similar to the C* program test samples.Responses to RAIs LTR-CDME-06-27-NP April 2006 Revision 0 18 3.0 References
- 1. Westinghouse Report, WCAP-16208-1', Revision 1, Supplement 1"NDE Inspection Length for San Onofre 2 & 3 Steam Generator Tubesheet Region Cold Leg Explosive Expansions," July 2005.2. N. Kalyanam (NRC) Letter to Richard M. Rosenblum (SCE) dated March 23, 2006,
Subject:
San Onofre Nuclear Generating Station, Units 2 and 3 -Request for Additional Information on the Proposed C* Amendment for Steam Generator Tube Inspection and Repair in the Tubesheet (TAC Nos. MC8850 and MC8851).3. SCE Letter to NRC, " Docket Nos. 50-361 and 50-362 Proposed Change Number NPF-10/15-564 Application for Technical Specification Improvement Regarding Steam Generator Tube Integrity San Onofre Nuclear Generating Station, Units 2 and 3," November 30, 2005.4. "Nuclear Services Policies & Procedures," Westinghouse Quality Management System -Level 2 Policies and Procedures, Effective 12/15/05.5. Westinghouse Report WCAP-15720, Revision 0, "NDE Inspection Strategy for Tubesheet Regions in CE Designed Units," CEOG Task 1154, July 2001.6. "Braidwood Station, Units 1 and 2 -Issuance of Exigent Amendments RE: Revision of Scope of Steam Generator Inspections for Unit 2 Refueling Outage 11 (TAC NOS.MC6686 and MC6687)," NRC Letter from G.F. Dick to C.M. Crane (Excelon), April 25, 2005.7. SCE Letter to NRC, "San Onofre Nuclear Generating Station, Units 2 and 3, Docket Nos.50-361 and 50-362, Proposed Change Number NPF-10/15-565, License Amendment Request, 'Proposed Technical Specification Change, Define the Extent of the Required Tube Inspections and Repair Criteria Within the Tubesheet Region of the Steam Generators'," November 3, 2005.References April 2006 LTR-CDME-06-27-NP Revision 0 Enclosure (6)Westinghouse Application for Withholding Proprietary Information from Public Disclosure with Affidavit Westinghouse Westinghouse Electric Company Nuclear Services P.O. Box 355 Pittsburgh, Pennsylvania 1 5230-0355 USA U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001 Direct tel: Direct fax: e-mail: (412) 3744419 (412) 3744011 maurerbf~westinghouse.com Ourref: CAW-06-2133 April 26, 2006 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE Subiect: LTR-CDME-06-27-P, Rev. 0, "Responses to NRC Request for Additional Information on License Amendment Request for Proposed Technical Specification Change Regarding Repair Criteria and Inspection Depth for Steam Generator Tubes within the Tubesheet Region, Southern California Edison San Onofre Nuclear Generating Station, Units 2 and 3, Docket Nos.50-361 and 50-362," (Proprietary)
The proprietary information for which withholding is being requested in the above-referenced reFort is further identified in Affidavit CAW-06-2133 signed by the owner of the proprietary information, Westinghouse Electric Company LLC. The affidavit, which accompanies this letter, sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission's regulations.
Accordingly, this letter authorizes use of the accompanying affidavit by Southern California Edis:n.Con-espondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW-06-2133, and should be addressed to B. F. Maurer, Acting Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.
Very truly yours, f F r Acting Manager egulatory Compliance and Plant Licensing Enclosures cc: G. Shukla A BNFL Group company CAuV-06-2133 bcc: B. F. Maurer (ECE 4-7A) IL R. Bastien, IL, IA (Nivelles, Belgium)L. Ulloa (Madrid, Spain) IL, IA C. Brinkrnan, IL, IA (Westinghouse Electric Co., 12300 Twinbrook Parkway, Suite 330, Rockville, MD 20852)RCPL Administrative Aide (ECE 4-7A) I L, I A (letter and affidavit only)A BNFL Group company CAW-06-21 33 AFFIDAVIT STATE: OF CONNECTICUT:
Ss COUNTY OF HARTFORD: Before me, the undersigned authority, personally appeared I. C. Rickard, who, being by me duly sworn according to law, deposes and says that he is authorized to execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse), and that the averments of fact set forth in this Affidavit are true and correct to the best of his knowledge, information, and belief: -1. C. Ic , icensing Project Manager Systems and Safety Analysis, Nuclear Services Westinghouse Electric Company, LLC Sworn to and subscribed before me thisA 6_e day of 4 2006 Not Public My Commission Expires: As_ _____
2 CAW-06-2 133 (1) I am Licensing Project Manager, Systems and Safety Analysis, in Nuclear Services, Westinghouse Electric Company LLC (Westinghouse), and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rule making proceedings, and am authorized to apply for its withholding on behalf of Westinghouse.
(2) I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of the Commission's regulations and in conjunction with the Westinghouse "Application for Withholding" accompanying this Affidavit.
(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged or as confidential commercial or financial information.
(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse.(ii) The information is of a type customarily held in confidence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence.
The application of that system and the substance of that system constitute Westinghouse policy and provide the rational basis required.Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows: (a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of 3 CAW-06-2 133 Westinghouse's competitors without license from Westinghouse constitutes E.competitive economic advantage over other companies.(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the 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, manufacture, shipment, installation, assurance of quality, or licensing a similar product.(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.(e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.(f) It contains patentable ideas, for which patent protection may be desirable.
There are sound policy reasons behind the Westinghouse system which include the following: (a) The use of such information by Westinghouse gives Westinghouse a compet;.tive advantage over its competitors.
It is, therefore, withheld from disclosure to protect the Westinghouse competitive position.(b) It is information that is marketable in many ways. The extent to which such information is available to competitors diminishes the Westinghouse ability lo sell products and services involving the use of the information.(c) Use by our competitor would put Westinghouse at a competitive disadvantage by reducing his expenditure of resources at our expense.
4 CAW-06-2 133 (d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage.
If competitors acquire components of proprietary information, any one comporent may be the key to the entire puzzle, thereby depriving Westinghouse of a competitive advantage.(e) Unrestricted disclosure would jeopardize the position of prominence of Westinghouse in the world market, and thereby give a market advantage to the competition of other countries.(f) The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage.(iii) The information is being transmitted to the Commission in confidence and, under the provisions of 10 CFR Section 2.390, it is to be received in confidence by the Commission.(iv) The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best of our knowledge and belief.(v) The proprietary information sought to be withheld in this submittal is that which is appropriately marked in LTR-CDME-06-27-P, Rev. 0, "Responses to NRC Request for Additional Information on License Amendment Request for Proposed Technical Specification Change Regarding Repair Criteria and Inspection Depth for Steam Generator Tubes within the Tubesheet Region, Southern California Edison San Onofre Nuclear Generating Station, Units 2 and 3, Docket Nos. 50-361 and 50-362," being transmitted by Southern California Edison letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk. The proprietary information as submitted for use by Westinghouse for San Onofre Nuclear Generating Station (SONGS), Units 2 and 3 enables Westinghouse to support utilities in identifying and applying a steam generator tubesheet inspection model and, in particular, 5 CAW-06-2133 to determine the tubesheet inspection length appropriate for the SONGS Units 2 an 3 steam generators, including: (a) The identification of important factors relevant to determining the recommended steam generator tubesheet inspection length, and (b) Development of a generic methodology for applying the inspection length model to utilities with NSSS plants.Further, this information has substantial commercial value as follows: (a) Westinghouse plans to sell the use of similar information to its customers for purposes of meeting NRC requirements for licensing documentation.(b) Westinghouse can sell support and defense of the inspection model.(c) The information requested to be withheld reveals the distinguishing aspects of a methodology which was developed by Westinghouse.
Public disclosure of this proprietary information is likely to cause substantial harm tc the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar inspection models and licensing defense services for commercial power reactors without commensurate expenses.
Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
The development of the technology described in part by the information is the result of applying the results of many years of experience in an intensive Westinghouse effort and the expenditure of a considerable sum of money.
6 CAW-06-2.133 In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and a significant manpower effort, having the requisite talent and experience, would have to be expended.Further the deponent sayeth not.
CAW-06-2 133 PROPRIETARY INFORMATION NOTICE Transmitted herewith are proprietary and/or non-proprietary versions of documents furnished to the ARC in connection with requests for generic and/or plant-specific review and approval.In order to conform to the requirements of 10 CFR 2.390 of the Commission's regulations concerning the protection of proprietary information so submitted to the NRC, the information which is proprietary in the proprietary versions is 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).
The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f)located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information.
These lower case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the affidavit accompanying this transmittal pursuant to 10 CFR 2.390(b)(1).
CAW-06-2 133 COPYRIGHT NOTICE The reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted to make the number of copies of the information contained in these reports which are necessary for its internal use in connection with generic and plant-specific reviews and approvals as well as the issuance, denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license, permit, Drder, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding.
With respect to the non-proprietary versions of these reports, the NRC is permitted to make the number of copies beyond those necessary for its internal use which are necessary in order to have one copy available for public viewing in 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 is insufficient for this purpose. Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.