ML102560144

Proposed Technical Specifications (TS) Amendment TS 5.5.9, Steam Generator (SG) Program TS 5.6.8, Steam Generator (SG) Tube Inspection Report License Amendment Request to Revise TS for Alternate Repair Criteria

ML102560144
Person / Time
Site:	Catawba
Issue date:	09/09/2010
From:	Hamrick G Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LTR-NRC-10-60
Download: ML102560144 (97)

Text

77iDuke DUKE ENERGY CAROLINAS, LLC Energy Cat~wba Nuclear Station 4800 Concord Road Carolinas York, SC 29745 September 9, 2010 10 CFR 50.90 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Catawba Nuclear Station, Unit 2 Docket Number50-414 Proposed Technical Specifications (TS) Amendment TS 5.5.9, "Steam Generator (SG) Program" TS 5.6.8, "Steam Generator (SG) Tube Inspection Report" License Amendment Request to Revise TS for Alternate Repair Criteria

Reference:

Letter from Duke Energy to NRC, same subject, dated April 28, 2010 The reference letter requested an amendment to Catawba Facility Operating License NPF-52 and the subject TS. This amendment request proposed to revise TS 5.5.9 to exclude portions of the tube below the top of the SG tubesheet from periodic SG tube inspections and plugging or repair. In addition, reporting requirement changes were proposed to TS 5.6.8. This change was supported by Westinghouse Electric Company, LLC, (Westinghouse) WCAP-17072-P, "H*:

Alternate Repair Criteria for the Tubesheet Expansion Region in Steam Generators with Hydraulically Expanded Tubes (Model D5)". This submittal requested a one-cycle approval for the Catawba Unit 2 End of Cycle 17 Refueling Outage and subsequent Cycle 18 operation.

As a result of a technical issue involving primary-to-secondary leakage during a Main Steam Line Break (MSLB) transient, the NRC placed its review of the amendment request on hold pending the resolution of this issue.

www. duke-energy.corn

U.S. Nuclear Regulatory Commission Page 2 September 9, 2010 Accordingly, this amendment request supplement transmits the technical information necessary for the NRC to continue its review of the amendment request. Attachment 1 to this letter contains a proprietary version of this technical information. consists of two parts. The first part is a description of alternate leakage calculation methods for H* for situations when contact pressure at normal operating conditions exceeds contact pressure at accident conditions.

The second part is a qualitative justification for not performing the full probabilistic H* analysis in conjunction with this proposed one-cycle amendment request. contains a non-proprietary version of this technical information.

As Attachment 1 contains information proprietary to Westinghouse Electric Company LLC, it is supported by an affidavit signed by Westinghouse, the owner of the information. The-attached affidavit (Attachment 3) sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses witlh specificity the considerations listed in paragraph (b)(4) of 10 CFR 2.390. Accordingly, it is requested that the information that is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR 2.390.

Correspondence with respect to the copyright or proprietary aspects of the information listed above or the supporting 'Westinghouse affidavit should reference the applicable Westinghouse letter and should be addressed to J.A.

Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company, LLC, P.O. Box 355, Pittsburgh, Pennsylvania, 15230-0355. contains the revised marked-up TS pages.

This supplement does not constitute a significant change to the original amendment request; therefore, the No Significant Hazards Consideration and the Environmental Consideration provided in the original amendment request continue to remain valid. Also, this supplement does not change any of the regulatory commitments provided in the original amendment request.

Duke Energy requests approval of this proposed amendment by September 24, 2010, to support implementation during the Catawba Unit 2 Fall 2010 End of Cycle 17 Refueling Outage. Once approved, the amendment will be implemented prior to requiring the SGs to be operable at the completion of the outage.

U.S. Nuclear Regulatory Commission Page 3 September 9, 2010 In accordance with 10 CFR 50.91, Duke Energy is notifying the State of South Carolina of this amendment request supplement by transmitting a copy of this letter and its non-proprietary attachments to the designated state official.

Should you have any questions concerning this information, please contact L.J.

Rudy at (803) 701-3084.

Very truly yours, George T. Hamrick LJR/s Attachments

U.S. Nuclear Regulatory Commission Page 4 September 9, 2010 George T. Hamrick affirms that he is the person who subscribed his name to the foregoing statement, and that all the matters and facts set forth herein are true and correct to the best of his knowledge.

G ýHa'mric, Station Manager Subscribed and sworn to me:

11/g 1Ir)

Notary P~blic My commission expires:

'date~

SEAL

U.S. Nuclear Regulatory Commission Page 5 September 9, 2010 xc (with attachments):

L.A. Reyes Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 G.A. Hutto, III Senior Resident Inspector (CNS)

U.S. Nuclear Regulatory Commission Catawba Nuclear Station J.H. Thompson (addressee only)

NRC Project Manager (CNS)

U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 11555 Rockville Pike Rockville, MD 20852-2738 xc (with non-proprietary attachments only):

S.E. Jenkins Manager Radioactive and Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

U.S. Nuclear Regulatory Commission Page 6 September 9, 2010 bxc (with attachments):

R.D. Hart (CN01 RC)

L.J. Rudy (CN01 RC)

P.W. Downing, Jr. (EC07C)

D.B. Mayes (EC07E)

C.J. Thomas (EC050)

NCMPA-1 NCEMC PMPA RGC File Document Control File 801.01 ELL-EC050

ATTACHMENT 2 Technical Information in Support of Amendment Request Supplement (Non-Proprietary)

0W estinghouse Westinghouse Electric Company Nuclear Services P.O. Box 355 Piitsburgh, Pennsylvania 15230-0355 USA U.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643 Document Control Desk Direct fax: (412) 374-3846 Washington, DC 20555-0001 e-mail: greshaja@westinghouse.com LTR-NRC-10-60 September 3, 2010

Subject:

Submittal of LTR-SGMP-10-95 P-Attachment, Rev. I and LTR-SGMP-10-95 NP-Attachment, Rev. 1, "H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions,"'

(Proprietary/Non-Proprietary) for Review and Approval Enclosed are copies of the proprietary/non-proprietary versions of LTR-SGMP- 10-95 P-Attachment, Rev. I and LTR-SGMP- 10-95 NP-Attachment, Rev. 1, "H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions" (Proprietary/Non-Proprietary).

Also enclosed is:

1. One (1) copy of the Application for Withholding Proprietary Information from Public Disclosure, AW- 10-2940 (Non-Proprietary), with Proprietary Information Notice and Copyright Notice.

2. One (1) copy of Affidavit (Non-Proprietary).

This submittal contains proprietary information of Westinghouse Electric Company LLC. In conformance with the requirements of 10 CFR Section 2.3 90, as amended, of the Commission's regulations, we are enclosing with this submittal an Application for Withholding Proprietary Information from Public Disclosure and an affidavit. The affidavit sets forth the basis on which the information identified as proprietary may be withheld from public disclosure by the Commission.

Correspondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference AW- 10-2940 and should be addressed to J. A. Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.

Very truly yours, J. A. Gresham, Manager Regulatory Compliance and Plant Licensing Enclosures

Westinghouse Non-Proprietary Class 3 LTR-SGMP-10-95 NP-Attachment, Rev. 1 H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions September 2010 Westinghouse Electric Company LLC P.O. Box 158 Madison, PA 15668

© 2010 Westinghouse Electric Company LLC All Rights Reserved 1

LTR-SGMP-10-95 NP-Attachment, Rev. 1 H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions Foreword:

Revision 1 of this document is issued to address specific comments received from the NRC during a meeting between the NRC, Industry and Westinghouse on August 24, 2010 regarding Revision 0 of this document. There are no changes to the methodology; the changes are to provide additional detail requested by the NRC staff. Nevertheless, Revision 1 is considered to replace Revision 0 in its entirety.

1.0 Introduction and Background The technical justification for the Alternate Repair Criterion, H*, for the Model D5 SGs is provided in Reference 1. The purpose of H* is to replace the tube-end weld with the hydraulic expansion joint as the primary pressure boundary in the SG. There are two principal requirements for H*:

1. Assure that the tube(s) does not pull out of the tubesheet under the most limiting loads during normal operating or accident conditions;

2. Assure that primary coolant leakage through the tube-to-tubesheet crevice is no greater than the leakage assumed in the Final Safety Analysis Report (FSAR) for the most limiting accident.

The model for leakage applied in Reference 1 is the Darcy formulation for leakage through a porous medium. The Darcy equation is:

Ap Eq. I 12pKl Where:

Ap is the driving potential (primary to secondary pressure difference)

[t is the fluid dynamic viscosity K is the loss coefficient for flow through the porous medium I is the length of the porous medium The Darcy formulation is used in Reference 1 to develop the ratio of leak rates between postulated accident induced conditions (SLB/FLB) and normal operating conditions (NOP). The driving heads (Ap) at both of these conditions are known, as are the temperatures and pressures to define the fluid viscosity (p). Because the physical length of the leak path is the same under both conditions, the length of the leak path is not a factor. The only remaining factor is the loss coefficient (K).

2

LTR-SGMP-10-95 NP-Attachment, Rev. 1 The available data for hydraulically expanded tubes in tubesheet simulants (References 3 and 4), both at room temperature and at elevated temperature, are utilized in Reference 1 to show that no correlation between loss coefficient and contact pressure exists for conditions that simulate the Model D5 SG conditions. However, because the data exhibit considerable scatter, confidence in this data analysis is low. Engineering judgment could suggest that loss coefficient might be related to the absolute contact pressure between the tubes and the tubesheet. Hence, a requirement was applied to the H* leakage analysis by the regulatory authorities that it is necessary to show that the contact pressure at accident induced conditions exceeds the contact pressure at normal operating conditions (SLB:NOP>1).

The calculated contact pressure results for all models of SG are, to a large degree, dependent on the temperatures at a particular operating condition. The limiting accident leakage condition for H* for the Model D5 SGs is the feed line break (FLB) condition, as documented in Reference 7. However, the limiting accident condition for the structural analysis of the Model D5 SGs is the SLB condition. The licensing basis for the Model 05 SG includes a SLB condition that differs from the SLB conditions in the licensing basis for the other SG models. The Model D5 SG SLB transient includes a significantly lower temperature; as a result, it cannot be shown that the contact pressures at accident conditions exceed those at normal operating conditions, and the criterion for contact pressure (SLB:NOP>1) is not met.

Consequently, it is necessary to utilize a different approach for leakage analysis that does not depend on loss coefficient being independent of contact pressure to show that the accident induced leakage value assumed in the FSAR is not exceeded.

Two alternate approaches are considered:

1. Parametric assumptions of loss coefficient dependency on contact pressure.

2. Application of parallel plate theory.

Both approaches rely on the existing Model D5 leak rate data to varying degrees. The approach of assuming various proportionality formulations between the loss coefficient and contact pressure and benchmarking them against the existing data is the most direct application. The latter approach utilizes accepted theory to calculate a flow area based on test results and relates that flow area (and consequential leak rate) to the contact pressure conditions for the test specimens to develop leak rates for both SLB and NOP conditions. This document discusses these two methods and their application to the H* leakage analysis for the Model D5 SGs; however, the methods discussed are generally applicable to other models of SG as well.

3

LTR-SGMP-10-95 NP-Attachment, Rev. 1 2.0 Leak Rate Data The available Model D5 test results are documented in References 3 and 4. For convenience, the leakage test results at high temperature for tests to simulate the NOP and SLB conditions are reproduced in Tables 1 and 2.

The normal operating leakage testing consisted of a primary pressure of [ ]ace psig and a secondary side pressure of approximately ] a,c,e psig. All leakage testing for the data contained in Tables 1 and 2 was conducted at 6000 F. As primary water leaked past the expanded segment in the test specimen, it flashed to steam and increased the pressure in an autoclave. The American Society of Mechanical Engineers (ASME) steam tables were utilized to calculate the increase in mass that accumulated due to the pressure increase; the amount of mass build up was then converted to a leak rate in grams/min (Reference 4). The mass flow rate was then converted into a volumetric flow rate at room temperature conditions.

The testing at accident conditions was done with atmospheric pressure on the secondary side of the autoclave. The leakage was collected for these tests by condensing any accumulation in the autoclave to room temperature water. The room temperature water was collected and weighed on a digital balance and the rate at which the water was collected was reported. The leakage was measured in gallons per minute at room temperature conditions.

Figure 1 shows the Model D5 simulation leak test data from Tables 1 and 2 plotted as a function of the calculated loss coefficient versus to calculated contact pressures in these tests. Tables 1 and 2 show the data for the 600'F tests performed at simulated NOP and SLB conditions. Additional test were run at an intermediate primary side pressure (approximately 1885 psi) and at room temperature (RT) at pressure differentials of 1450, 1885, and 2835 psid. For the RT tests, the calculated contact pressures were lower due to the absence of differential thermal growth between the tube and the tubesheet. The data from all of these tests i.e., four groupings of data, are shown on Figure I to provide a complete benchmark for the intended purposes - to test various assumptions of relationships between the loss coefficient and the contact pressure to evaluate their effect on predicted leak rate ratios.

The loss coefficient shown on Tables 1 and 2 was calculated by the method of Reference 3. Appendix A of this document provides a discussion of the process for calculating the loss coefficient shown on Tables 1 and 2.

Because the contact pressure between the tube and the tubesheet was not measured in the leak tests, the contact pressures shown on Tables 1 and 2 were calculated based on application of thick shell equations such as were applied in Reference 1 for the NOP conditions. The calculations for these tests assumed that the crevice pressure was at the saturation pressure for the secondary side temperature for entire length of the specimens (See Table 1 of Appendix A). Only a single calculation was performed for each significant condition; therefore the contact pressures shown are the same for each test despite small variations in the actual applied pressure as shown on Table 1.

4

LTR-SGMP-10-95 NP-Attachment, Rev. 1 It is noted that the absolute values of the loss coefficients shown on Figure 1 are not used in the calculation of the leak rate ratios in this document. The only purpose of the data is to provide a benchmark for assumptions made regarding the potential correlations between Kand Pc.

Examination of Figure 1 leads to several observations:

1. The calculated loss coefficient exhibits significant variability at specific calculated contact pressures. This is not unexpected for a test in which the measured leakage rate is extremely small (drops per minute). The overall conclusion to be drawn from these tests is that there is very little leakage through a hydraulically expanded joint, even with an open, pressurized fluid source (i.e., no resistance through a crack).

2. Similar data variability exists at all pressure conditions tested, suggesting that the data variability is, indeed, a measurement uncertainty, rather than a physical test specimen or process issue.

3. When the data are viewed collectively as shown on Figure 1, within the range of pressure conditions represented, there is no evidence of a discontinuous relationship between loss.....

coefficient and contact pressure. If a discontinuity existed within the range of test conditions, the median point of the data scatter should be at a discernibly different level at contact pressures greater than at the point of the discontinuity. A statistical fit of the natural logarithm of Kversus Pc actually exhibits a slightly negative slope. If a discontinuity existed in the range of the contact pressures of the data, the statistical fit would be expected to exhibit a positive slope because of the higher loss coefficients at the higher contact pressures. It can be reasonably concluded that within the database range of contact pressures, no discontinuity in a postulated relationship between K and Pc exists.

5

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 1 NOP Elevated Temperature Leakage Data (6000 F)

Sample ID Test Condition (Average Ap)

{ Leakage Flow (gpm)

K (inm4)

Calculated Contact Pressure (psi) a,c,e

+/- -I- + F 4

+/- + + F +

+/- -I- F 4

.4- -I- .4- F 4

+/- +/- + F 4

.4- + 4

+/- F 4

+ + + i 4

___ __ I I ___ ___ ___ I 6

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 2 SLB Elevated Temperature Leakage Data (6000 F)

Calculated Sample ID Test Condition Crevice Leakage Flow K Contact (Average Ap) Length(in) (gpm) (in4 ) Pressure (psi) ace 2

7

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e, Figure 1 Model D5 Leakage Tests: Calculated Loss Coefficient vs. Calculated Contact Pressure 9

LTR-SGMP-1O-95 NP-Attachment, Rev. 1 3.0 Loss Coefficient Parametric Proportionality It is the purpose of this study to evaluate the sensitivity of the leak rate ratio (SLB:NOP) to various assumed relationships between loss coefficient and contact pressure.

The criterion (PCSLB:PcNop>1) implies the postulate that the leakage loss coefficient at lower contact pressures is less than the leakage loss coefficient at higher contact pressures. Further, if this criterion is not met, it implies that this could cause a large accident induced leakage if the contact pressure at accident conditions is predicted to be lower than that at normal operating conditions. To address this postulate, using the available leak rate data from Reference 4 as a benchmark for loss coefficient versus contact pressure, various relationships between loss coefficient and contact pressure were assumed that provided a positive slope for the relationship between loss coefficient and contact pressure. The acceptance criteria for the relationships are based on engineering judgment. For example, a relationship that results in an inflection point so that, at some contact pressure, the slope of the relationship turns negative was rejected because it violates the basic premise that the loss coefficient should increase with increasing contact pressure. Relationships with a positive slope were considered which bound .thaedata .both as an upper bound of the K values and as a lower bound of the K values.

Although a relationship that meets the premise but bounds the available data from the lowest loss coefficient at the lowest contact pressure to the highest loss coefficient at the highest contact pressure (based on the available data) also is not considered credible, it was, nevertheless, considered at the request of the NRC.

The underlying assumption of this approach is that the presumed relationship between loss coefficient and contact pressure is a continuous function and does not include any discontinuities over the range in which it is applied. For example, if exposure to a loading condition of interest permanently changes the characteristic of the flow path so that the slope of the loss coefficient to contact pressure relationship changes, this approach could not be used. All conditions of interest must lie on a continuous line represented by a single relationship.

The issue of correlation between loss coefficient and contact pressure was discussed at a meeting among the Argonne National Laboratory (ANL) personnel, the NRC, Westinghouse and industry representatives (Reference 2). During those discussions, the hypothesis was presented by ANL that, at very high contact pressures, the asperities in the crevice that define the porous medium could become "flattened," resulting in a different crevice condition and potentially reduced loss coefficient upon return to a lower contact pressure. The contact pressures hypothesized were those approp riate to severe accident conditions, thought by ANL to be much higher than those for the conditions of interest for NOP and SLB.

For the SG hydraulic expansion transition, the condition of the crevice is set by the hydraulic expansion of the tubes into the tubesheet. The minimum hydraulic expansion pressures are approximately [ ]a ...

ksi. The maximum predicted operating contact pressures for NOP and SLB conditions are less than approximately [ ] a,ce ksi. Therefore, it is concluded that the crevice characteristics are established by 9

LTR-SGMP-10-95 NP-Attachment, Rev. 1 the manufacturing process and that they do not change as a result of any operating conditions. This shows on a physical basis that a discontinuity in a presumed loss coefficient correlation to contact pressure is extremely unlikely to exist in the contact pressure range of interest. (Note that no residual contact pressure from the hydraulic expansion of the tube is included in this analysis. If residual contact pressure were included, the predicted contact pressures would be greater but still well bounded by the hydraulic expansion pressure.)

This parametric proportionality approach utilizes the Darcy formulation for leakage through a porous medium but does not assume that the value of the loss coefficient is independent of the contact pressure. The Darcy formulation for leakage through a porous medium is given byEquation 1.

Consider an electrical analogy to the leakage through the crevice based on Ohm's law:

V(potential) = I(current)/R(Resistance) or in terms of flow:

I = V/R Where:

I, the current, is equivalent to leak rate, 0 V, voltage, is the driving potential, equivalent to Ap R, resistance is equivalent to the flow resistance, (12gKl), which must be calculated.

For an electrical system with resistances in series, the total resistance is the sum of the resistances.

The leak rate through the crevice above H* can be considered a series related network of flow resistances in which the total resistance is the sum of the segment resistances, as for the electrical analogy. The calculations for H*divide the thickness of the tubesheet into a number of axial segments, although not of equal length. No attempt was made to evenly distribute the segment over the tubesheet thickness; the segment lengths are those defined by the structural model used in the H*

analysis. At the end-point of each segment, contact pressures are calculated as part of the normal H*

calculations. The assumptions necessary for this approach are:

1. The local crevice length is the distance between the axial locations where contact pressures are calculated.

2. The contact pressure that applies over the local crevice length is the average of the contact pressures at the end-points of the local length.

The total resistance to flow above the H* distance is the sum of the local resistances in the segments above H*.

10

LTR-SGMP-10-95 NP-Attachment, Rev. 1 The lengths of the segments are known and are defined as follows based on the structural model used to calculate H*:

Distance from Segment TTS (in.) Length (in.)

0 NA 1

2 1 4.13 2.13 10.51 6.38 15.03 4.52 17.03 2 19.03 2 21.03 2 The viscosity of the fluid is known for both the NOP and SLB conditions:

Viscosity Viscosity Conditions (Ibm/ft-sec) (Ibf-sec/in 2)

NOP Conditions 618 F, 2250 psi J 5.38E-05 1.16E-08 SLB Conditions 300 F,2560 psi I 1.27E-04 2.74E-08 Viscosity varies very little with pressure; the principal variation is due to temperature; therefore the pressure influence on viscosity was ignored.

The driving potential over the full length of the crevice, assuming that the length of the crevice is defined by the H* length, approximately 17 inches, is the difference between the primary side pressure and the secondary side pressure appropriate to each of the NOP and SLB conditions. The driving head ratio (SLB:NOP) used in this analysis was 2.01.

If it is assumed that the loss coefficient is a function of the contact pressure as the criterion SLB:NOP>I implies, a series of assumptions regarding the relationship can be made. Only relationships that result in positive slope of K over a range of contact pressure need be considered. An assumption that the loss coefficient declines with increasing contact pressure is not credible because it would result in a higher leak rate at SLB conditions if the criterion SLB:NOP>1 were met. Relationships that contain an inflection point can be ignored because they are physically impossible without a change in the leak path characteristics. Based on the available test data, a number of relationships were assumed, some with extreme slopes, and others that essentially envelope the upper and lower bounds of the available data.

11

LTR-SGMP-1O-95 NP-Attachment, Rev. 1 It should be noted that the Kversus contact pressure data from the tests were used only as a benchmark. The absolute values of Kshown on Figure 1 are not used in the analysis; only the value of K predicted by the assumed relationships is used in the calculations. The assumed relationships, shown in Figure 2, are not mathematical correlations to the data; they are, as stated, assumed relationships that meet the criterion of increasing loss coefficient with increasing contact pressure. 'Different slopes of the relationships were investigated as well as various absolute positions relative to the available database (i.e., Exp-1, Exp-2, Exp-3, Exp-4 and Exp-5). The purpose was to investigate to what degree a presumed function between loss coefficient and contact pressure would affect the leak rate ratio between SLB and NOP conditions.

Leak Rate Ratio Calculation for C2 Model Contact Pressures Using the assumed relationships, it is possible to calculate the loss coefficient for the average segment contact pressures and develop a total resistance to flow above H*for both the NOP and SLB conditions.

The contact pressures at each elevation at each tubesheet radius were calculated using the H*

calculation methods, that is, application of the square cell (C2) model. Figures 3 through 8 show the calculated axial contact pressure profiles for each radius of interest for the Model D5 SGs.

Table 3 provides the matrix of contact pressures for each radius and each elevation, and also provides the contact pressure ratios (SLB:NOP). The contact pressure ratios are not used directly in the calculation of the resistance factors; rather, the predicted contact pressures at each condition, NOP and SLB, are used separately to calculate the local segment and cumulative resistances above H*, assumed to be 17 inches.

The "resistance," 12liKl, is calculated for each segment above the H* value, 17 inches below the top of the tubesheet, and the resistances are summed to determine the total resistance above H*. Based on the total resistance in the crevice, leakage values are calculated at each tubesheet radius for both NOP and SLB conditions. The ratio of the SLB leakage to the NOP leakage is defined as the leak rate ratio.

Table 4 provides the calculated local segment resistance values. These values are based on viscosity in units of lbf-sec/in 2. The applicable values for viscosity at NOP and SLB conditions are shown above. The local resistances shown on Table 4 assume a power relationship between Kand Pc of:

K = O.15*(P,) 4.5 This relationship is identified as the "Power-2" relationship on Figure 2.

Table 5 summarizes the predicted leak rate ratios for the various relationships between loss coefficient and contact pressure shown in Figure 2. Figure 9 is a graphical representation of the predicted leak rate ratios at each tubesheet radius based on the relationships shown on Figure 2. The largest leak rate ratio predicted in this study is [ ]",, based on the selected "Power-2" relationship. The "Power-2" relationship is the diagonally bounding relationship that is not considered a credible interpretation of the data. Further, the leak rate value of [ la.e is a local value at tubesheet radius of 49.825 inches.

12

LTR-SGMP-10-95 NP-Attachment, Rev. 1 The maximum leak rate ratio for all other locations and all other assumed relationships is [ I..... . The leak rate ratios predicted with the most likely relationship, the exponential relationships, are all equal to, or less than, [ c regardless of the slope or position of the relationship relative to the data. It is ac,e noted that the more aggressive relationships in terms of slope and intercept tend to result in lower leak rate ratios than the more moderate relationships.

These results are consistent with a first-principles evaluation.

Driving Head Ratio, SLB:NOP -2 Viscosity Ratio, SLB:NOP "0.5 Length Ratio 1 Contact Pressure Ratio, SLB:NOP >0<1 (SLB:NOP ratios >1 meet the contact pressure criterion).

The local resistances should vary by a factor of less than 1 to approximately 1 because, if the SLB contact pressure exceeds the NOP contact pressure, the criterion is met. For each relationship assumed, the sensitivity of the loss coefficient is very small over the applicable contact pressure range, even when a strong relationship is assumed. It is concluded that a very large difference in contact pressures would be required for a functional relationship between loss coefficient and contact pressure to result in a significant leak rate ratio. In general, it is concluded that it is not the functional relationship between K and P, that is of concern, but rather that the contact pressure ratio is the principal factor. For H*, the difference between the SLB contact pressures and the NOP contact pressure are very modest, in a range bounded by [ ] a'cepsid. An evaluation was made to address the sensitivity of the leak rate factors to changes in the predicted contact pressures. The results of this. evaluation indicate that the leak rate ratios are not sensitive to the magnitude of the changes in the contact pressure profiles that may be anticipated.

The results on Table 5 and Figure 9 are based on the up-to-date contact pressure profiles using the C2 structural model (see Figures 3 through 8). A brief descriptiori of the C2 model is provided in Appendix C to this document.

In regard to the relationships between K and Pc shown on Figure 2, the logarithmic relationship (K proportional to ln(Pc)) is counterintuitive and, in fact, produces unrealistic results when applied in the resistance model. For some locations, negative resistances are calculated because of the mathematical relationship. These negative resistances were set to zero to complete the study; however, it is concluded that this relationship is not a physically realistic relationship and it is, therefore, shown only for information.

13

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Leak Rate Ratio Calculation for Thick Shell Model Contact Pressures In response to an NRC request, the same analysis described above was completed for the Model D5 SGs based on contact pressures calculated using the Thick Shell Equation (TSE) approach discussed in Reference 1. The TSE approach was applied in Reference 1 to calculate contact pressures for the NOP condition. The contact pressures at the SLB condition in Reference I was an application of an early evolution of the C2 model as discussed in Section 6.3 of Reference 1. For this evaluation, contact pressures calculated using only the TSE model were used for both NOP and SLB conditions. Appendix B provides the predicted contact pressure axial profiles for the Model D5 SG based on application of the TSE model only.

Figure 10 shows the SLB:NOP leak rate factor results for the application of the resistance model to the contact pressures calculated with the TSE model. With the exception of the two most extreme assumptions for relationships between K and Pc (Power-1 and Power-2), the predicted leak rate ratios are all less than 3.0. The third most aggressive relationship, Exp-1, which has a significantly steep slope, yields a maximum leak rate ratio of approximately [ ]a,"e near the outer radius of the tubesheet. The assumed relationships that best represent the most probable fit to the K versus Pc data all yield leak rate ratios of less than about [ ] a,c,e The extreme relationships (Power-1 and Power-2) are not considered credible relationships. The Power-1 fit represents an intentionally severe slope that bounds more than 80% of the data. Similarly, the Power-2 relationship is a fit that maximizes the slope by connecting the lowest value of K at the lowest contact pressure to the highest value of K at the highest contact pressure and also bounds about 80% of the data. It is generally accepted that the best fit of a scattered database is near the average of the database. The Exp-2 relationship most nearly approximates the mean of the data and yields a maximum leak rate ratio of about [ ] a,c,e Crevice Pressure Conditions The NRC staff requested that a sensitivity study of crevice pressure on leak rate ratio be performed.

Reference 1 provides the crevice pressure axial profile based on tests performed to determine the crevice pressure conditions resulting from a large flaw at the bottom of a test simulant of the tubesheet with a tube hydraulically expanded into the tubesheet simulant. It was previously assumed that any primary to secondary leakage would flash to steam at the secondary side saturation pressure; however, the test revealed that leakage does not flash to steam but remains in a liquid form for most of the length of the expansion. These results led to the development of a normalized crevice pressure ratio versus normalized crevice length curve that is the basis of the Reference 1 calculations and the current calculations (See Figure 6-84 of Reference 1).

The impact of this test data was to reduce the contact pressure between the tube and the tubesheet owing to reduced Ap across the tube wall. Because the crevice pressure cannot exceed the primary side pressure, any reduction in the crevice pressure profile will increase the contact pressure between the 14

LTR-SGMP-10-95 NP-Attachment, Rev. 1 tube and the tubesheet for all operating conditions considered. As seen from the above evaluations, the leak rate ratio is not sensitive to the absolute contact pressure. Rather, the leak rate ratio is sensitive to the difference between the NOP and SLB contact pressure ratio if the SLB contact pressure is less than the NOP contact pressure. This can be seen by comparing the results based on the TSE model with those from the C2 model. The C2 model exhibits generally larger contact pressure ratios (SLB:NOP) than those from the TSE model.

To assess different assumptions on the crevice pressure profile, it is necessary to perform a significant level of structural analysis to determine the proper relationship between SLB contact pressure and NOP contact pressure. Any change in the crevice pressure profile will affect both the NOP and SLB contact pressure predictions.

The least conservative assumption would be the original assumption, that is, that the entire crevice is at the secondary side pressure. In that event, the contact pressures would be reduced, and the leak rate ratios would tend to smaller values. The most conservative assumption is the crevice pressure profile applied in the current calculations. It is not possible for the crevice pressure to exceed the primary pressure and it is not credible that the crevice pressure would not decline with increasing crevice length.

Therefore, variations in the crevice pressure profile would result in higher contact pressures and a reduced leak rate ratio trend.

A quantitative evaluation of leak rate ratio sensitivity to a crevice pressure would require extensive structural analysis to develop contact pressure profiles for both NOP and SLB conditions. It would be expected that the results from such a study would be enveloped by the current leak rate ratio results for any credible assumption of crevice pressure profile.

15

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 3 NOP and SLB Contact Pressures and Ratios for the Model D5 SG Segment Tubesheet Radius (inch) length 4.437 10.431 18.139 26.703 42.974 49.825 Average Pc NOP (psi) a,c,e BTS 2.000 2.000 2.000 4.515 6.386 2.129 1.000 1.000 Average P, SLB (psi)

BTS 2.000 a,ce 2.000 2.000 4.515 6.386 2.129 1.000 TS 1.000 ____ ____1____

Ratio of Pc (SLB:NOP) a,c,e BTS 2.000 2.000 2.0010 4.515 6.386 2.129 1.000 TTS 1.000 16

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 4 Loss Coefficient Matrices for "Exp-2" Fit; K= 3.5E+12*exp(SE-04*Pc)

Tubesheet Radius (inch)

Segment 4.437 10.431 18.139 26.703 42.974 49.825 Length NOP Conditions BTS 2.000 a,c, 2.000 2.000 4.515 6.386 2.129 T"-S 1.000 1.000 SLB Conditions BTS 2.000 ac,e 2.000 2.000 4.515 6.386 2.129 S 1.000

"-S 1.000 Table 5 Summary of Leak Rate Ratios (SLB:NOP) for Assumed Relationships Between K and Pc Based on C2 Model Results for Contact Pressure TS Radius 4.437 10.431 18.139 26.703 42.974 49.825 Function Leak Rate Ratio (SLB:NOP)

Exp-1 a,c,e 1* t I I Exp-2 Exp-3 Exp-4 Exp-5 Linear Power-i Power-2 Logarithmic _____ __________

17

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure 2 Assumed Relationships between K and Pc Compared to Leak Rate Test Data 18

a,c,e LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure 3 Figure 4 Model D5 SG; Contact Pressure Axial Profile at Radius = 4.437 a,c,e Model D5 SG; Contact Pressure Axial Profile at Radius = 10.431 a,c~e Figure 5 Figure 6 Model D5 SG; Contact Pressure Axial Profile at Radius = 18.139 Model D5 SG; Contact Pressure Axial Profile at Radius = 26.703 19

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e a,c,e Figure 7 Figure 8 Model DS SG; Contact Pressure Axial Profile at Radius = 42.974 Model D5 SG; Contact Pressure Axial Profile at Radius = 49.825 20

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure 9 Leak Rate Ratio Distribution for Various Assumed Relationships between Kand Pc Based on C2 Model Results 21

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure 10 Leak Rate Ratio Distribution for Various Assumed Relationships between K and P, Based on Thick Shell Equation Model Results 22

LTR-SGMP-10-95 NP-Attachment, Rev. 1 4.0 Application of Parallel Plate Flow Theory A second approach to calculating leak rate ratio is an application of parallel plate flow theory from Reference 5, which provides a formulation for calculating steady, laminar flow between fixed, parallel plates. It is assumed that flow continuity applies and that the flow is unidirectional, constant and laminar. The use of this formulation for the tube in the tubesheet is appropriate because the direction of fluid particles can be assumed to be in a single direction along the tube-to-tubesheet bore. Adapted to the geometry of concentric cylinders such as the tube in the tubesheet bore, the governing equation from Reference 5 is:

3 ZzDApa Q-- 12U1/ Eq. 2 Where:

Q is the flow rate of the fluid through the gap between the tube-to-tubesheet bore, in3/sec Ap is difference in pressure (or driving head) acting to force the fluid through the gap, lbf/in2 Al is the viscosity of the fluid, lbf-sec/in2 (Note that the viscosity values provided on page 11 are in units of Ibm/ft-sec.)

D is the tubesheet bore inner diameter in inches I is the axial length of hydraulic expansion, in inches a is the gap between the tube and the tubesheet, in inches The use of this relationship is acceptable for the tube-in-tubesheet case because the flow is continuous and laminar, and can conservatively be assumed to be in a single direction (axial) within the tubesheet crevice.

Solving for the gap "a" yields:

S:3!2ulQ Eq. 3 a D-J

' FcDAp 23

LTR-SGMP-10-95 NP-Attachment, Rev. 1 This is the separation (gap) between concentric cylinders required to yield flow rate Q under a driving head Ap. Using this equation and the available test data, the gap between the tube and collar for each of the test specimens (Reference 4) can be calculated based on the measured flow rates for each specimen under different test conditions. The average gap is calculated for the various pressure differentials developed along the length of the test specimens. The pressure differentials along the length of the test specimens are based on the crevice pressure profiles for NOP and SLB conditions documented in Reference 1. The axial crevice pressure profile from Figure 6-84 of Reference 1 was applied to determine the Ap at the bottom of the tubesheet (collar), at the neutral axis and at the top of the collar (see Table 6).

It is of interest that the crevice pressure ratio in Figure 6-84 of Reference 1 does not go to a ratio that equates to the secondary side pressure at the top of the tubesheet (i.e., at a depth ratio equal to 1.0).

The crevice pressure profile is based on use of only one of two test specimen data sets at the instruction of the NRC (Reference 2). Application of the crevice pressure correction in the current licensing basis results in a conservative condition in which the full Ap across the tube is not realized within the thickness of the tubesheet. For example, at NOP conditions, under which the primary side pressure is 2250 psi and the secondary pressure is 827 psi, the expected Ap across the tubes at the top of the tubesheet is 1423 psid; however application of the crevice pressure profile as shown in Figure 6-84 of Reference 1 yields a Ap of 1262 psid.

The resulting pressure differentials used for this analysis are shown on Table 7. They differ from the applied pressure differentials shown on Tables 1 and 2 for the reason noted above. It is the intent of this analysis to apply the same methods and approaches applied in the overall H* analysis.

With the known pressure differentials (Table 7), using Equation 3 it is possible to calculate the location-specific (BTS, neutral axis, TTS) average gap at the specific pressure differentials for each of the test specimens. Example calculations are shown on Tables 8 and 9 for the NOP and SLB conditions. This calculation provides the relationship between the driving head for leakage and the average required gap derived from the test specimen measured leakage, taking into account the condition-specific values of viscosity. This relationship is summarized on Table 10. Note that the values on Table 8 are based on using the entire specimen length (3, 6, 9 or 12 inches) for all conditions. The effect of assuming shorter crevice lengths is discussed further, below.

Figure 11 shows a correlation of the calculated gap with the measured leakages for the test specimens.

This figure includes the calculated gaps for each of the specimens when subjected to NOP and SLB condition differential pressures as noted on Table 7. Because the full Ap across the specimens was used, the full length of the specimens was also used in the calculations. Good correlations are obtained between the measured leakage and the calculated gaps for the both of the tested operating conditions, 2

NOP and SLB. The fit parameter, R , is greater than 0.8 for both conditions. These correlations will be subsequently used to develop a correlation between calculated contact pressure and calculated gap.

24

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Based on the pressure differentials on Table 7 for the test specimens, the contact pressure between the tube and the collar was calculated for the specific locations on the test specimen using an FEA model that consists of a tube in a collar. This model is the same basic model used to address the issue of effect of eccentricity on contact pressure which is documented in Reference 6. (Only the basic model was used; no effects of eccentricity are included.) The model assumes initial line-on-line contact between the tube and the collar at zero contact pressure and calculates the contact pressure between the tube and the collar when internal pressure and temperature are applied. No residual contact pressure from the expansion process is applied. (This model is essentially the same as the square cell model used in the H* calculations.) The contact pressures resulting when the differential pressure and temperature conditions on Table 7 are applied are summarized on Table 11.

Sufficient information is now available to develop the relationship between gap size (from Table 10) and contact pressure (from Table 11) by combining the tables. Table 12 shows the results of this combination based on matching gap and contact pressure to the applicable AP. A correlation was developed between gap and contact pressure from this data as shown on Figure 12.

The necessary information is now available to calculate SG-specific leak rates based on Equation 3. The expected increase in leakage during a postulated SLB event relative to normal operating conditions can be defined using a ratio of Equation 3 for the different SG operating conditions. The resulting equation for SLB leakage factor can be written in the form:

ApSLB x gap(asLB )3 QSLB /1 SLB Eq. 4 QNOP p 6NOP xgap(a NOP )3 1LI NOp Using the correlation developed in Figure 12 for tube-to-tubesheet bore gap as a function of tube-to-tubesheet bore contact pressure, i.e.,

a,c,e and recognizing that the SLB contact pressure will be a ratio, r, of the NOP contact pressure, the leak rate ratio can be represented as a function of r (SLB:NOP ratio) and the operative equation becomes:

QDBA _ APDBA /PNOP r[ c E....

QNOP ApVOP /IDBA Eq.5 The exponent on r results from the power of the contact pressure in the gap to Pc correlation

]a,c,e raised to the third power.

25

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Figure 14 shows the leak rate ratio as a function of the SLB:NOP contact pressure ratio, r. Only SLB:NOP contact ratios below 1 are shown because at values greater than 1, the SLB:NOP>1 criterion is met a priori.

At the request of the NRC, a similar calculation was performed, but assuming shorter crevice lengths for the test specimens. For example, at the bottom of the tubesheet where a Ap of 1 psi is calculated based on application of the crevice pressure profile, a crevice length of 1 inch was assumed. Similarly, for the Ap at the neutral axis, half the length of the specimenwas assumed. However, for the full predicted driving head, the full length of the specimen was assumed. For these assumptions, the correlation between contact pressure and gap, Figure 13, changes because the gap is a function of length of the crevice (see Equation 3). The resulting leak rate factor as a function of contact pressure ratio is shown on Figure 14 as well. It is concluded that the originalassumption of full crevice length for all conditions is the most conservative when applying the parallel plate theory to calculate leak rate ratio (SLB:NOP).

However, application of shorter crevice lengths is the more realistic case.

The ratio of expected steam line break leakage to normal operating leakage (i.e., leakage rate factor) is calculated using the predicted location-specific contact pressure at tubesheet elevations within the H*

distance. The leak rate ratio is an expression of how significantly the leakage can change as a result of the change in driving head, viscosity and contact pressure.

Figures 15 and 16 show the calculated leak rate factors for the Model D5 SGs based on the crevice pressure profiles provided in Figures 3 through 8. The principal factor driving the predicted leak rate ratios is r, the ratio of contact pressures, as shown in Figure 14. The more realistic calculation based on reduced crevice lengths results in leak rate factors of less than 2.5 for all radii at all elevations. Except for two points at elevations less than 5 inches below the top of the tubesheet for the outermost radius (49.825 inches), all other predicted leak rate factors are less than one. The two values greater than 1 are the result of the predicted crevice pressure profile shown in Figure 8 for the TS radius of 49.825 inches. At the H* depth for the Model D5 (approximately 17 inches), the SLB contact pressure exceeds the NOP contact pressure; thus the leak rate ratio is controlled at this elevation. Similarly, at about 2 inches below the top of the tubesheet, the SLB contact pressure again exceeds the NOP contact pressure and by a greater difference than at approximately 17 inches. The criterion SLB:NOP>1 is met between the H* distance and approximately 12.5 inches below the top of the tubesheet, and again between approximately 2 inches below the top of the tubesheet and the top of the tubesheet.

Consequently, the two predicted local leak rate ratios greater than 1 are of no consequenceand can be ignored.

From Figures 15 and 16 it is seen that the smallest leak rate ratios occur at, or just above, the H* depth.

At a distance approximately 2 inches above the H*distance, the leak rate ratios are less than [ ]a,c,e. At a distance of approximately 6 inches above the H* distance, the predicted leak rate ratios are all less than [ a,c,e or less than [ I a,c,e for the case of reduced crevice length . Therefore, because absolute 26

LTR-SGMP-10-95 NP-Attachment, Rev. 1 leakage will be principally limited at, or below, the H* distance and the leak rate ratios above H* are bounded by values of [ ac,e or less, it is concluded that the maximum leak rate ratio applicable to the D5 SGs is less than [ Iace based on application of the parallel plate theory. This value is bounded by the limiting leakage factor of 3.27 for a postulated FLB in the current technical basis for the Model D5 SG (References 1 and 7).

Table 6 Axially Dependent SLB:NOP Differential Pressure Ratios TS Axial APNOP APSLB Ratio Position(l) (in.) (psi) (psi) a,c,e 0.00 2.00 4.00 6.00 10.52 16.90 19.03 20.03 21.03 (1) Axial Position .00 is the bottom of the tubesheet (2) A 1 psi pressure differential was assumed at the assumed source of the leakage Table 7 Driving Head in Crevice for Test Specimens NOP T SLB Axial Location Test Condition 2235 psig 2835 psig Ap (psid)

BTS 1 1 Neutral Axis 600OF 468 520 TTS 1262 2536 27

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 8 Example Gap Calculation 1' ) for Specimen Tested at NOP Conditions Crevice Leakage Leakage Flow Calculated Gap at Specimen ID Test Condition Length FlowL ag Fn3lsecw 1262 psid (in.) (gpm) (in.) a,c,e 1-b 15-c 15-d 16-c 16-d 16-h 8-a 8-b 14-a 14-b 2-d 2-e 2-f 7-a 7-b 13-a 13-b 13-f 13-g 13-h (1) Similar calculations were performed for each specimen at other significant pressure differentials.

28

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 9 Example Gap Calculation for Specimen Tested at SLB Conditions MeasuredCacltdGpt Nominal Test Specimen MeasuredMCalculated Gap at Specimen ID MeaurekLekag 3 2536 psid Condition

___ ______ _ _m) Length (in.) Leakage _ __(in_ /sec)

_ __ _ _(in.) 2i36 (1)

() _

1-a a,c,e 1-C 15-a 15-e 15-f 16-a 16-e 16-f 8-C 8-d 14-c 14-d 2-a 2-c 2-g 2-i 7-e 7-f 13-e 13-j 13-j (1) This value is the maximum Ap across the tube, based on a nominal Ap of 2560 adjusted for crevice pressure as documented in Reference 1.

29

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 10 Gap Related to Driving Head for Test Specimens Ap (psid) Gap (in.)

i(1) 9.64E-04 S(2) 7.79E-04 468 9.97E-05 520 1.20E-04 1262 7.17E-05 2536 7.07E-05 Notes:

(1) For NOP Condition (2) For SLB Condition Table 11 Calculated Contact Pressures for the Leak Test Specimens Conditions NOP SLB Primary Pressure 2235 psi 2835 psi Axial Location Secondary Pressure 785 psi 0 psi Temperature 600°F 600°F Tube Wall AP Contact Pressure (psi)

NOP SLB NOP SLB BTS 1 1 459 459 Neutral Axis 468 520 934 971 TTS 1262 2536 1506 2425 Table 12 Relationship between Gap and Contact Pressure Contact AP(psid) Pressure (psi) Gap (in) 1 459 9.64E-04 1 459 7.79E-04 468 934 9.97E-05 520 971 1.20E-04 1262 1506 7.17E-05 2536 2425 7.07E-05 30

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a, c, e Figure 11 a, c, e Leakage Rate as a Function of Gap Figure 12 Calculated Gap as a Function of Tube-to-Tubesheet Contact Pressure (Full Crevice Length) 31

LTR-SGMP-10-95 NP-Attachment, Rev. 1

- 1 a, c, e Figure 13 Calculated Gap as a Function of Tube-to-Tubesheet Contact Pressure a, c, e (Reduced Crevice Length)

Figure 14 Leak Rate Ratio vs. Contact Pressure Ratio 32

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a, c, e Figure 15 Model D5 Leak Rate Ratios at All Radii; Parallel Plate Model; a, c, e Full Crevice Length Figure 16 Model D5 Leak Rate Ratios at All Radii; Parallel Plate Model; Reduced Crevice Length 33

LTR-SGMP-10-95 NP-Attachment, Rev. 1 5.0 Summary and Conclusions This document considered the implication to the leak rate ratio between SLB conditions and NOP conditions when the predicted contact pressures at SLB conditions are less than the predicted contact pressures at NOP conditions in the H* analysis. An evaluation was required because the NRC had applied a criterion that requires that SLB contact pressure exceed the NOP contact pressure at all elevations in the tubesheet. For the Model D5 SGs, this criterion could not be met.

Two approaches were utilized:

1. An approach that assumes various relationships between loss coefficient and contact pressure using the available leak rate data as a benchmark for the relationships. The available data includes a relatively wide range of scatter and is not amenable to a high confidence correlation between loss coefficient and contact pressure. However, the data does provide a suitable benchmark for developing the assumed relationships. The assumed relationships are not mathematical correlations based on the data but are chosen to test the significance of a presumed correlation between loss coefficient and contact pressure when considering the H*

SLB:NOP leak rate ratio.

2. Application of the theory for flow between parallel plates: This theory is readily adapted for the situation of a cylinder in a cylinder. In this approach, the measured leak rates from the test data are utilized to calculate the gap between the tube and the collar necessary to result in the measured leak rate. From this, the measured leak rates can be related to the driving across the test specimen. Different assumptions were made regarding the lengths of the leak path to evaluate the effect of these assumptions on the calculated leak rate ratios. Using the calculation methods applied in the H*calculations, the contact pressures between the tube and the collar (simulated tubesheet) in the test specimens were calculated for the same driving head used in the gap calculations. From these two calculations, a correlation between contact pressure and gap was developed. This correlation was used to determine the gap and subsequently the predicted leakage using the predicted Model D5 H* contact pressures for each of the SLB and NOP conditions.

The available data are used as a benchmark for both approaches. There is no evidence in the data that a discontinuity exists in any relationship between loss coefficient and contact pressure within the range of the contact pressures tested. The data reasonably represent the predicted range of contact pressure from the H* analysis; indeed, they are calculated using the same methods.

That no discontinuity in the data exists is supported by the manufacturing process of the test specimens.

A discontinuity in the loss coefficient relationship with contact pressure requires that the characteristics of the crevice are changed by exposure to a particular test condition. Both the test specimens and the SG tubes were expanded at pressures of about [ ]... e ksi While the predicted contact pressures at 34

LTR-SGMP-10-95 NP-Attachment, Rev. 1 operating conditions are less than about [ ] a ksi. Therefore, no test or operating condition has the potential to change the crevice characteristic.

The results from the parametric application of assumed relationshipsbetween loss coefficient and contact pressure, all of which result in an increase in loss coefficient with an increase in contact pressure, yield a maximum leakrate ratio of less than [ Ia," based on the contact pressures predicted using the C2 model. Application of contact pressures based on the Thick-Shell model yields somewhat higher leak rate ratios, but only for the relationships between K and Pc that are not considered to be credible. For the credible relationships between K and Pc, leak rate ratios of [ a,c,e or less are predicted usingthe thick-shell-based contact pressures.

The parametric resistance approach is analogous to a simple electrical circuit and is a straightforward application of the Darcy equation for flow through a porous medium. The Darcy formulation for leakage is the reference basis for the H* leakage calculation in Reference 1. Total flow resistance is based on a segment-wise calculation of flow resistance over the entire crevice above H* based on the predicted NOP and SLB contact pressures for the Model D5 SGs. The reference contact pressures were those calculated using the C2 model, the current reference model for H* calculations. A separate analysis was performed using contact pressures based on application of thick-shell equations.

The only additional assumption made is that the loss coefficient is an increasing function of contact pressure. It is shown that there is very little sensitivity of leak rate ratio to the assumed relationship between loss coefficient and contact pressure within the range of contact pressures at issue between SLB and NOP conditions predicted for the Model D5 SGs using the C2 model. The leak rate ratio increases with larger ratios of contact pressure (NOP:SLB) but not to the degree that the current licensing basis is challenged. Within a relatively narrow range of contact pressures, there is little change in the resistance to flow in the crevice regardless of the assumption of relationship between Kand Pc.

The other operative factors, driving head ratio and viscosity ratio, effectively cancel each other because the driving head ratio is approximately 2 and the viscosity ratio is approximately 0.5 for the conditions of interest.

The application of the parallel plate theory utilizes the available test data to calibrate gap size versus contact pressure and applies that correlation to calculate the leakage at both NOP and SLB conditions to develop the leak rate ratio. The parallel plate theory is independent of the loss coefficient, but depends on the measured leak rates. Although the measured leak rates are somewhat scattered, application of the parallel plate theory results in good correlations between gap and driving head, indicating that the data is a good benchmark for the applications in this document.

The results from the most conservative application of the parallel plate theory yield an applicable leak rate ratio of less than 1.5. A more realistic application of the model yields an applicable leak rate ratio of approximately 1.0. All but two local leak rate ratios calculated are less than 1.5 for the most conservative assumption of crevice length and less than 1.0 for a more realistic assumption of crevice length. The largest calculated leak rate ratios (between 2 and 3) occur at the outermost radius of the 35

LTR-SGMP-10-95 NP-Attachment, Rev. 1 tubesheet and are in a tubesheet span that is bounded by spans above and below, but within the H*

.inspection distance, that exhibit much smaller leak rate ratios. Nevertheless, even the highest predicted leak rate ratios inthis span are within the leak rate ratio included in the current licensing basis for H* for the Model D5 SGs.

Of the two alternative approaches to calculating leak rate ratio, the resistance model is the more straightforward approach that is readily confirmed by a first-principles analysis, and is recommended for application to the H* technical justification. The only assumption required for this approach is that the available leakage database, although somewhat scattered, provides a reasonable benchmark for the loss coefficient versus contact pressure. This assumption is borne out by the good correlations achieved in the application of the parallel plate theory, which are based on the same database. This assumption is also tempered by the fact that leak rate ratios are of interest. If the absolute value of loss coefficient were to increase or decrease over the range of contact pressures of interest, little variation in the calculated leak rate ratios would be expected and is, in fact, demonstrated by the assumed relationships. The contact pressures for the test specimens were calculated using the same methods included in the current Model D5 licensing basis, WCAP-17072-P, that take into account a correction for crevice pressure on the Ap across the tubes. The approach utilized in the resistance model relies exclusively on the accepted leakage model for H*, the Darcy model, and on the same structural calculations that are used for determining the H* distance. Contact pressures using both the C2 model and the Thick-Shell equation model were used in this analysis. The driving potential for the resistance model is the known pressure difference across the entire crevice length as defined by H*for the Model I5 SGs (approximately 17 inches). The simplicity of the model permits a parametric study of various assumed correlations between loss coefficient and contact pressure that are the implied underlying basis for the criterion that SLB contact pressure must exceed NOP contact pressure to limit the accident induced leakage.

A leak rate ratio of 1.2 is recommended for the Model D5 conditions. This value is bounded by the limiting leak rate factor of 3.27 for the postulated FLB event in the current H* licensing basis for the Model D5 SGs.

36

LTR-SGMP-10-95 NP-Attachment, Rev. 1 6.0

References:

1. WCAP-17072-P Rev. 0, "H*: Alternate Repair Criteria for the Tubesheet Expansion Region in Steam Generators with Hydraulically Expanded Tubes (Model DS)," Westinghouse Electric Company LLC, May 2009.

2. USNRC Memo from Andrew Johnson to Allen L. Hiser, "Summary of the October 29 and 30, 2008 Category 2 Public Meeting with the Nuclear Energy Institute (NEI) and Industry to Discuss Modeling Issues Pertaining to the Steam Generator Tube-to-Tubesheet Joints," November 5, 2008.

3. CN-SGDA-03-119, "Calculation of Loss Coefficient for Model D5 Steam Generators,"

Westinghouse Electric Company LLC, November 10, 2003.

4. STD-MCE-03-49, "Determination of Model D5 Tube-to-Tubesheet Leakage Resistance for H-star Program for CBE/DCE/DDP/TCX," November 4, 2003.

5. Introduction to Fluid Mechanics, Fox and McDonald, 2nd Edition.

6. LTR-SGMP-10-78, "Effects of Tubesheet Bore Eccentricity and Dilation on Tube to Tubesheet Contact Pressure and their Relative Importance to H*," Westinghouse Electric Company LLC, (to be issued).

7. LTR-SGMP-09-100, "Response to NRC Request for Additional Information on H*; Model F and Model D5 Steam Generators," Westinghouse Electric Company LLC, August 14, 2009.

37

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Appendix A Calculation of Loss Coefficient for Model DS High Temperature Hydraulic Expansion Leakage Tests 38

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Loss Coefficient Calculation Summary Introduction A series of tests was performed to simulate the Model D5 tubesheet hydraulic expansion leakage and its potential for leakage if a through-wall flaw were present at the bottom of the joint. By applying a known primary-to-secondary pressure differential to a simulated tube-to-tubesheet interface containing known flaws, it was possible to measure the leakage flow rate of the fluid through the hydraulically expanded joint. The known flaw in the tube was six 0.060 inch holes through the tube at the upstream end of the specimens.

Leakage flow in the tube-to-tubesheet crevice is assumed to be governed by the Darcy equation for laminar flow according to a previous tube-to-tubesheet leakage analysis that was performed in Reference 1 of this appendix. The Darcy equation, which is shown below, provides a correlation between the volumetric flow rate of a fluid flow and the applied pressure difference across the "porous medium," in this case, the tube to tubesheet crevice.

Q AP (Eq. 1) 12KuL where Q = volumetric flow rate in ft3 / sec L = crevice length in inches AP = pressure difference in psi 4

K = loss coefficient in inch

= dynamic viscosity in lbf sec / ft2 From Equation 1, the loss coefficient can therefore be written as If the volumetric flow rate is converted to gallons per minute, the loss coefficient equation is rewritten as K=37.4( AP L Q',uj (q .

where Q' is the volumetric flow rate in gallons per minute.

39

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Tube-to-tubesheet leakage testing was performed to measure the leakage volumetric flow rates under various temperature and pressure conditions. The tests consisted of applying an internal tube pressure to a tube in tubesheet simulant, in which the tube included a known flaw (six 0.060 inch throughwall holes in the tubes) that freely permitted primary-to-secondary leakage. Tests were performed in an autoclave at high temperature (600'F). Any leakage through the tube to tubesheet crevice was collected and the volumetric flow rate for the leakage was calculated. (Note that the leakage [i.e. mass flow rate] through the crack, the leakage through the crevice, and the leakage emerging from the tube-to-tubesheet interface are all assumed to be equal.)

Loss Coefficient Calculations for Heated Autoclave Conditions Because the possibility that high temperature fluid may flash to steam in the crevice, the measured leakage flow from the 600*F autoclave tests cannot simply be entered into Equation 3 in order to calculate the experimental loss coefficients. To account for the possibility of flashing in the crevice, a modified version of the DENTFLO Code (Reference 1) is used to calculate the crevice loss coefficient for the high temperature tests. DENTFLO models the tube crack in series with the crevice. Because of the free communication between the primary side fluid and the crevice, the DENTFLO crack properties were set so that only a very small pressure drop was developed across the "flaw" and a correction factor for the remaining pressure drop through the crevice was made as described below.

Rather than run DENTFLO for each experimental test case, it was assumed that C

K = -- (Eq. 4)

Q, where the value of the crack flow constant, C, is a function of the primary-to-secondary pressure difference and is given by the following equation L =3(Eq. 5)

Since only the volumetric flow rate (Q') in Equation 4 is known, a range of values for the loss coefficient was used to approximate a crack flow constant. Based on prior analysis, Reference 2, it was expected, that the loss coefficients would be within the range of 3x10 10 to lxO10 4 inch 4 . Therefore, a crack flow constant was determined for eight different assumed loss coefficients within the expected range. For the 8 assumed values of Kfor each test specimen expansion length, the crack flow constants were found to remain fairly constant; thus, the average crack flow constant for the given pressure differential and crevice length was utilized for subsequent calculations. Table A-1 is the matrix of conditions for which a crack flow constant was developed. Table 2 summarizes the average crack flow constants for the conditions considered.

40

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table 2 is an example of the results of the DENTFLO runs and the calculated values of the crack flow constants for the 1,450 psi primary-to7secondary nominal pressure differentials. In Table A-2, column 1 shows the primary side to secondary side pressure differences, column 2 shows the assumed values of K within the expected range of loss coefficients for the crevice flows, and column 3 shows the crevice lengths. Column 4 shows the leak rate in the primary side, as taken directly from the DENTFLO output files. Column 5 shows the leak rate in the secondary side, which is calculated by multiplying the leak rate in the primary side by the ratio of the density of water at the primary side conditions (42.3 Ibm/ ft 3) and the density of water at the secondary side conditions (62.3 lbm/ft3). (Note that the density of the water at the primary side conditions for all primary-to-secondary side pressure differentials was assumed to be the fluid density for water at a saturation temperature of 600°F. Since the density varies very little for changes in primary side pressure, this is a reasonable assumption.) Column 6 provides the crack flow constants, which are the product of the loss coefficients (Column 2) and the leak rates in the secondary side (Column 5). Finally, column 8 provides the average crack flow constants for the values in the expected loss coefficient range for each crevice length. For example, the crack flow constant calculations in the first row of 2 for a loss coefficient of 3.00 x 1010 inch-4 are provided below.

_ PprimaryQ =(42.3 1(2 10-')= 1.478 x 10-'

Qsec.....la,y = 62.3

,Pseconary .7 gpm C= = (3.00 x0I'WX1.478xlo-')= 4. 4 3 4 x 109 gpm

.KQsecOc.,,Y inch4 As expected, the values of the crack flow constants are seen in Table A-2 to have minimal variation over the range of loss coefficients evaluated (3x10°' to 1x1014 inch 4). Because there is little variation in the crack flow constant over the range of assumed loss coefficient, the average value of the crack flow constant for each pressure differential were calculated and are provided in Table A-3.

Table 3 shows the crack flow constant for all test conditions and specimen lengths.

With the average crack flow constants for each experimental condition known, the experimental volumetric flow rates can be used to calculate the experimental values of the crevice loss coefficients using Equation 4. Table A-4 provides the calculated loss coefficients for the complete data set for the Model D5 tests performed at the 600°F conditions.

41

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Example Calculation for Specimen 1-b The governing equations are Equations 4 and 5:

Input Parameters Parameter Value Units Specimen Length L 12 inches Driving Head Ap 1450 psid Measured Secondary 9.80E-05 gpm Side Leakage Crack Constant from C 1.321E+09 gpm/in 4 DENTFLO By way of example, for Sample 1-b in Table i on Page 6 of this report, the loss coefficient, K, is calculated as follows. This test is simulating normal operating conditions and the length of the hydraulic expansion in the test specimen is 12 inches. Therefore, referring to Table 2 of this Appendix A, based on the DENTFLO results, the average crack flow constant for the 12 inch long test specimen at 1450 psid is calculated to be 1.321E+09 gpm in 4 .

As noted above, Table 2 in Appendix A is an example of the results of the DENTFLO runs and the calculated values of the crack flow constants for the 1,450 psi primary-to-secondary nominal pressure differentials. In Table 2, column 1 shows the primary side to secondary side pressure differences, column 2 shows the assumed values of K within the expected range of loss coefficients for the crevice flows, and column 3 shows the crevice lengths. Column 4 shows the leak rate in the primary side, as taken directly from the DENTFLO output files. Column 5 shows the leak rate in the secondary side, which is calculated by multiplying theleak rate in the primary side by the ratio of the density of water at the primary side conditions (42.3 Ibm/ ft 3) and the density of water at the secondary side conditions (62.3 lbm/ft 3). (Note that the density of the water at the primary side conditions for all primary-to-secondary side pressure differentials was assumed to be the fluid density for water at a saturation temperature of 600'F. Since the density varies very little for changes in primary side pressure, this is a reasonable assumption.) Column 6 provides the crack flow constants, which are the product of the loss coefficients (Column 2) and the leak rates in the secondary side (Column 5). Finally, column 8 provides the average crack flow constants for the values in the expected loss coefficient range for each crevice length. For example, the crack flow constant calculations in the first row of 2 for a loss coefficient of 3.00 x 1010 inch-4 are provided below.

42

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Qseco,17dar = Pprimary gpiir = ")(2.177x 10')= 1.478x 10O 62.3 gpm P~secornary 6.

C=KQ...onav = (3.00 x . 100X1.478 x 10_') =4.434 x 109 inch' gpmi As expected, the values of the crack flow constants are seen in Table 2 to have minimal variation over the range of loss coefficients evaluated (3x10°' to lxlO14 inch-4). Because there is little variation in the crack flow constant over the range of assumed loss coefficient, the average value of the crack flow constants for each pressure differential were calculated and are provided in Table 3. Referring to Table 2, the average value for crack flow constant for a 12 inch crevice length at a pressure differential of 9 .4 1450 psid calculated to be 1.321 x 109 gpm in As noted above, loss coefficient, K,is calculated using, Eq. (4). Again referring to Table 1 on Page 6, the secondary side leakage (Q') was measured at [ ] ..c.. gpm. Therefore, the loss coefficient for 4

Sample 1-b is calculated to be [ ]a~ce in- .

References

1. NSD-E-SGDA-98-107, "Software Release Letter for the DENTFLO Code, Version 1."

2. TH-98-37, Revision 0, "Vogtle/Yonggwang Tubesheet Crevice Leakage," G. P. Lilly, 11/5/98.

43

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table A-1 Matrix of Conditions for DENTFLO Analyses DENTFLO Test Pressure Difference Primary Pressure Secondary Pressure Pressure Difference (psi) (psia) (psi)

(psia) 1,450 2,265 800 1,465 1,885 1,915 15 1,900 2,835 2,865 15 2,850 44

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table A-2 Crack Flow Constant Calculations for DENTFLO Run Differential Pressure = 1,450 psi a,c,e 45

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Table A-3 Average Crack Flow Constants for the Test Conditions a.c.e 46

LTR-SGMP-10-95 NP-Attachment; Rev. 1 Table A-4 Loss Coefficients for Experimental Data Measured at 600°F Heated Conditions F a,c,e 47

1 NP=Attachment, Rev.

LTR-SGMP-10-95 Appendix B Thick Shell Equations DS SG Based on Application of Profiles for the Model Contact Pressure 48

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure B-1 Model D5 SG Contact Pressures Based on Application of the Thick Shell Equation Model; Radius=4.437 a,c,e Figure B-2 Model D5 SG Contact Pressures Based on Application of the Thick Shell, Equation Model; Radius=10.431 49

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure B-3 Model DS SG Contact Pressures Based on Application of the Thick Shell Equation Model; Radius=18.139 a,c,e Figure B-4 Model b5 SG Contact Pressures Based on Application of the Thick Shell Equation Model; Radius=26.703 50

LTR-SGMP-10-95 NP-Attachment, Rev. 1 a,c,e Figure B-5 Model DS SG Contact Pressures Based on Application of the Thick Shell Equation Model; Radius=42.974 a,c,e Figure B-6 Model DS SG Contact Pressures Based on Application of the Thick Shell Equation Model.

Radius=49.825 51

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Appendix C C2 Model Summary 52

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Overview WCAP-17072-P, Figure 1-1, describes the process of calculating H*. There are three principal processes required:

1. Calculation of the overall structural response to the operating conditions of interest; normal operating conditions (NOP) and the limiting accident conditions, steam line break (SLB). The structural model for the tubesheet complex (channel head, tubesheet, stub barrel and divider plate) is a 3-D FEA model that provides the local deformations at the locations of the tubes in the tubesheet. The model is described in detail in WCAP-17072-P.

2. The local deformations are input to another structural model that calculates the axially distributed contact pressures between the tubes and the tubesheet. In WCAP-17072-P for NOP conditions, the structural model employed utilizes the classical thick-shell equations to calculate contact pressures. Because application of this model did not yield the desired contact pressure ratio between SLB conditions and NOP conditions (SLB:NOP>1), an alternate model was employed to calculate contact pressures for the SLB conditions. This model was the ancestor of the current square cell model (C2) that is employed to calculate contact pressures for both NOP and SLB conditions for the Model D5 SGs.

3. The contact pressures from step 2 are input to an integration code that calculates the cumulative forces resisting tube pullout for the limiting operating conditions, NOP or SLB.

This Appendix provides a discussion of the C2 model currently used in the analysis for the Model D5 SGs, the basis of the contact pressure profiles contained in the body of this report. Only a general description of the model and its application is provided here because formal documentation of the model is not yet complete and will be the subject of the final technical justification of H*.

Description of the Square Cell (C2) Model The C2 model is a planar model of a tube in a tubesheet segment. The tubesheet segment can be visualized as a square local segment of the tubesheet that is defined by a single tube pitch (1.0625 inch for the Model D5) centered on the location of a tube. The model includes the tubesheet bore and a tube in its expanded diameter but without any residual contact pressure from the hydraulic expansion process. Thus, in its unloaded state, the tube is in zero-pressure line-on-line contact with the tubesheet bore.

The loading conditions applied to the square cell model are temperature, which varies axially through the tubesheet, the internal tube pressure modified by the axially-dependen t crevice pressure, and planar displacements at the model boundaries, which are taken from the 3D-FEA model of the tubesheet complex when it is loaded by temperature increase and differential pressures applicable to 53

LTR-SGMP-10-95 NP-Attachment, Rev. 1 the operating conditions of interest. Previously, when applying the thick-shell model-, similar displacement were applied directly to the tubesheet bore, however, in the C2 model application, the displacement conditions are applied to the boundaries of the model and the model determines the conditions at the actual tube-to-tubesheet interface.

To calculate the axial contact pressures profile for a specific tube, the temperatures and displacements appropriate to nine points through the thickness of the tubesheet are input separately to the model along with the tube-wall Ap appropriate to each elevation to determine the contact pressure at each elevation. This process assumes that the centerline of the tube in question remains straight, e.g., that no bending of the tubesheet occurs while the displacement input boundary conditions include the total effects of temperature and pressure loading. Ignoring the coupling due to tubesheet bending is a very conservative application of this model.

The input boundary conditions include displacement in both axes of the plane. Conceptually, this is similar to the original analysis using the thick-shell equations, but the application details are different.

Previously, the radial displacement was taken directly from the 3D FEA model, and the circumferential displacement was derived from the radial displacement (see Section 6.3 of WCAP-17072-P). For application of the C2 model, which is driven by the boundary displacements, it was desired that the radial displacements be calculated directly in the 3D FEA model of the tubesheet complex. To facilitate this, the 3D-FEA model was modified by adding the same mesh used on the tubesheet centerline face perpendicular to the divider plate one and two pitches into the depth (not thickness) of the tubesheet.

This permitted obtaining the displacements in the direction parallel to the divider plate directly.

The 3D FEA model mesh was also modified for other reasons not directly related to application of the C2 model. For example, to avoid applying a factor to account for a non-functional divider plate, the model was changed to directly reflect that the upper 5 inches of the divider plate were assumed to be non-existent. Further, other changes were made to the 3D FEA model mesh to more properly represent the axial thermal profile through the thickness of the tubesheet. Figure C-1 illustrates the final mesh for the 3D FEA tubesheet complex model.

54

LTR-SGMP-10-95 NP-Attachment, Rev. 1 Figure C-1 Final Mesh for 3D FEA Tubesheet Complex Model 55

Westinghouse Proprietary Class 2

• )Westinghouse I To: D.H. Warren M.W. Ryan Date: September 7, 2010 cc D. A. Testa W. Bedont A. Roslund C. L. Hammer C.D. Cassino G. W. Whiteman From: Steam Generator Management Programs Your ref:

Ext 724-722-5082 Our ref: LTR-SGMP-10-107 Fax: 724-722-5889 Subject Catawba Unit 2: Assessment of Probabilistic Value of H*

References:

Attached please find LTR-SGMP-10-107 P-Attachment (proprietary) and LTR-SGMP-10-107 NP-Attachment (non-proprietary). These documents are a qualitative assessment of the probabilistic H*

length based on application of the Square Cell (C2) model for calculating H*. This assessment was requested by Duke Power in response to a commitment made to the NRC during a meeting on August 24, 2010 among the NRC, Industry and Westinghouse to provide such an assessment. This assessment is a necessary item to support the Duke Power licensing efforts for application of the H*

criteria during the September 2010 outage.

Please transmit the attachments to Duke Power (Daniel Mayes and Parker Downing) through normal project channels.

Author: *ElectronicallyApproved Verified: *ElectronicallyApproved Hermann Lagally C. D. Cassino Fellow Engineer Senior Engineer SG Management Programs SG Management Programs Approved: *ElectronicallyApproved Damian A. Testa, Manager SG Management Programs

• Electronicallyapproved recordsare authenticatedin the Electronic DocumentManagement System 1

Westinghouse Non-Proprietary Class 3 LTR-SGMP-1O-107 NP-Attachment Catawba Unit 2: Assessment of Probabilistic Value of H*

September 2010 Westinghouse Electric Company LLC P.O. Box 158 Madison, PA 15668

© 2010 Westinghouse Electric Company LLC All Rights Reserved 1

LTR-SGMP-10-107 NP-Attachment Introduction Reference 1 provided the technical justification for H* for the Model D5 SGs. In this report, the model used to calculate the tube-to-tubesheet contact pressures that define the H* length for the normal operating condition (NOP) was based on the classical thick-shell equations. However, it was necessary to employ a different model, the square cell model (C2 model), for the Model D5 SGs to show that the contact pressures at steam line break (SLB) conditions exceeded those at NOP conditions to meet a criterion specified by the NRC; that is that contact pressures at SLB conditions must exceed those at NOP conditions (SLB:NOP>I). Application of the C2 model as documented in Reference 1 led to NRC questions (Reference 2) regarding the C2 model.

Because it was not possible to meet the SLB:NOP>1 criterion using the thick-shell model, the C2 model was further developed and consistently applied for both NOP and SLB conditions because it was thought that this application would resolve the issue of the SLB:NOP>I criterion. While not completed yet, the results from application of the C2 model also show that the contact pressures at SLB conditions do not exceed those at NOP conditions over the full depth of the H* distance. Further, application of the C2 model predicts that over a short distance from the top of the tubesheet, the contact pressure is zero for most of the tubesheet radii of interest for H*. However, notwithstanding the short distance of zero contact pressure at the top of the tubesheet, the mean predicted length of contact required to meet the H* criteria to prevent tube pullout is comparable between the two approaches, application of the thick shell model and application of the C2 model.

The mean contact length is based on nominal material properties and is the baseline case for the probabilistic assessment of H* that defines the licensed inspection depth for application of H*. This document provides a qualitative assessment of the probabilistic value of H* for the criteria established by the industry, that is 0.95 probability at 50% confidence (95/50) for the population of tubes that is exposed to the limiting conditions. This document also provides information regarding the H* distance at a more restrictive probabilistic goal as an information point.

Assessment Reference 3 is a summary of the probabilistic assessments for all of the models of SG that are H*

candidates. Included in Reference 3 are the results of the Monte Carlo analysis for the Model D5 SGs that defines the 95/50 value of H*. The basis of the Monte Carlo analysis was the mean value of H*,

]ace inches from the top of the tubesheet. Table 1 summarizes the results of the Monte Carlo analysis for the Model D5 SG as documented in Reference 3. Industry requirements are to meet 95/50 probabilities; the data for 95/95 probability is provided for information.

2

LTR-SGMP-10-107 NP-Attachment Table 1 Summary of Probabilistic H* Values for the Model DS SGs Based on the Thick Shell Equation Model Total Mean H* for Each SG H* for All Tubes in the Plant No. of No. of No.

of Tubes Tubes in Value of (inch) (inch)

H*

Loops per SG the Plant (inch) 95/50 95/95 Plant 95/50 95/95

[ la,c,e j]aeeaI [ [ ] a,c,e j] a,c,e 4 4570 18280 (1) (1) (1) (1) (1)

(1) Includes 0.3 inch BET allowance The limiting condition for the H* values in Table 1 was the NOP condition as documented in Reference 1.

Because of this, it was noted by the NRC that all tubes in the plant are exposed to the same condition and that, therefore, the probabilistic analysis should be based on the entire complement of tubes in the bundle. This is the basis on which the requested H* inspection depth was licensed for the temporary application of H*.

From application of the thick-shell model, the required length of contact is [ ]a,c,e inches minus the a,c,e inch allowance for the position of the bottom of the expansion transition (BET), or [ a,c,e inches. This represents the distance over which the integrated pullout resistance forces equilibrate to the limiting condition end-cap loads.

For consistent application of the both the C2 model and the thick shell model to the Model D5 SGs, the limiting condition for the H* depth is the SLB transient. In Reference 1, the NOP analysis is based on the thick shell model while the SLB analysis is based on the original version of the C2 model. The definition of the SLB transient includes only one of the four SGs in the Model D5 plants. Consequently, the population of tubes for the probabilistic analysis for H* based on use of the C2 model is limited to the number of tubes in a single SG.

Based on application of the C2 model, the mean H* distance is predicted to be [ , inches. This a~c,e value applies at the critical radius for H*, which is [ ] a"c"einches, the same as the critical radius in Reference 1. As shown in Figure 6 of Reference 4, the predicted length of zero contact pressure is

[ c] inches. Therefore, the required length of contact between the tubes and the tubesheet is

] ace inches ([ ] aC"e), slightly less than that predicted using the thick shell model. The reason a shorter contact length is required based on the C2 model is that the rate of increase of contact pressure (slope) is steeper than that predicted by the thick-shell equation model. One can conclude from this that both approaches to the H* calculations predict reasonably the same result; in other 3

LTR-SGMP-10-107 NP-Attachment words, that one analysis validates the other. For this reason, it is reasonable to assume that the probabilistic analysis based on the thick-shell model would also apply to the C2 model.

From Table 1, the incremental length required to achieve a probabilistic H* value at 95/50 for a single SG is [ ] a,ce:inches ([ ]ac"e). All of the values in Table 1 include the [ ] ac,e inch allowance for the BET. A further increment of [ j ace inch is required to achieve a probability level of 95/95 for a single SG. Table 2 shows the results for the predicted probabilistic values based on application of the C2 model when the same increments are applied to the C2 model based mean H* value.

Table 2 Estimate of Probabilistic H* Values for Application of the C2 Model Additional H*

Mean H* from C2 H* Increment to Estimated 95/50 I Incrementtio to Estimated 95/95 Model Achieve 95/50 H* from C2 Model Achieve 95/95 H*from H rmCC2 Model oe J a,c,e I a~ce J a,c,e [ .]a,c,e [ ]a~ce It is necessary to adjust these values for the crevice pressure profile. The basis of this adjustment is discussed in Reference 1, Section 8, with reference specifically to Figure 8-1. For an initial predicted value of H* of [ a,c,e inches, and adjustment of [ ac,e inches is required to account for the difference in the crevice pressure profile for the initial prediction of [ j ..... inches. Therefore, the final 95/50 estimated value of H* is [ ] ac,e inches. The same increment, [ ] a,c,e inch, applies to this value to achieve the 95/95 probability level.

The currently requested inspection depth for the Model D5 SG is 16.95 inches. The estimated 95/50 H*

depth provides significant margin, [ j a,c,e inches, compared to the licensed value. At the 95/95 probability level, the margin is [ ] a,c,e inches.

Additional Considerations There are significant additional conservatisms that are inherent to the H* analysis that should also be recognized.

1. The C2 model is a realistic representation of the manner in which tubesheet displacements are transmitted to the tube-to-tubesheet bore interface. Application of the C2 model to the H*

analysis is extremely conservative because it is implicitly assumed that the various segments that constitute the tubesheet thickness are collinear. The tubesheet displacements are the result of temperature and pressure loading; therefore, because bending of the tubesheet contributes to the displacements, the centerline of any tubesheet bore is not straight. When the curvature of the centerline of the tubesheet bores is included, the contact pressures 4

LTR-SGMP-1O-107 NP-Attachment significantly increase, and the length of predicted zero contact pressure at the top of the tubesheet will be significantly decreased or eliminated. An increase in contact pressures will decrease the length of contact required to meet the H* pullout criteria, and reduction of the zero contact pressure length will directly decrease the predicted H* length. Therefore, the margin to the requested inspection depth of 16.95' inches is significantly greater.

2. The H* analysis neglects the contribution from residual contact pressure resulting from the hydraulic expansion. The hydraulic expansion process applies a minimum of [ ]a,,,e ksi pressure to the ID of the tube to achieve expansion of the tube into the tubesheet bore. The probabilistic variability in the H* length is principally due to potential variations in the material properties of the tubesheet and the tube. Regardless of the properties of the tubesheet(s) and the specific tubes at specific locations, the expansion process assures that a level of residual contact pressure exists at all tube locations. If residual contact pressure were included in the H*

analysis, the predicted contact pressures would increase, the predicted length of zero contact pressure would decrease and the required length of contact to meet the H* pullout criteria would decrease. Therefore, neglecting residual contact pressure in the H* calculations provides a significant margin to the predicted H* length.

Summary and Conclusions

1. Based on C2 model results, the SLB condition is the limiting condition for H*.

2. Application of the C2 model to calculate the H* distance results in a short length of zero contact pressure at the top of the tubesheet at most tubesheet radii, including the critical radius 1a,c,e inches.

3. The required length of contact to meet the H* pullout criteria based on the C2 model is slightly shorter compared to similar calculations based on the thick-shell model. Because of the similarity of the results from both methods, the change in length from the available probabilistic assessment for the thick shell model results is considered to be applicable to the C2 model as well.

4. When considering the additional length required to achieve the required goal of 0.95 probability at 50% confidence, and at even higher confidence, the resulting H* values exhibit significant margin compared to the proposed inspection depth of 16.95 inches.

This is the request of record for the Model D5 SGs. The current Catawba Unit 2 request is expected to be for an inspection distance of 20.0 inches from the top of the tubesheet. The stated margins in this document will increase accordingly.

5

LTR-SGMP-10-107 NP-Attachment

5. Several unquantified conservative assumptions exist in the analysis that provide added assurance that there is significant margin between the predicted H* depth and the requested H*

depth of 16.95 inches.

References:

1. WCAP-17072-P, Rev. 0, "H*: Alternate Repair Criteria for the Tubesheet Expansion Region in Steam Generators with Hydraulically Expanded Tubes (Model D5)," Westinghouse Electric Company LLC, May 2009.

2. USNRC Letter, "Vogtle Electric Generating Plant, Units 1 and 2- Transmittal of Unresolved Issues Regarding, Permanent Alternate Repair Criteria for Steam Generators (TAC Nos. ME1339 and ME 1340),"

November 23, 2009.

3. LTR-SGMP-09-104 -P Attachment, Rev. 1, 'White Paper on Probabilistic Assessment of H*,"

Westinghouse Electric Company LLC, August 13, 2009.

4. LTR-SGMP-10-95 P-Attachment, "H* Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions," September 2010.

6

ATTACHMENT 3 Westinghouse Authorization Letter with Accompanying Affidavit, Proprietary Information Notice, and Copyright Notice

eWestinghouse Nuclear Services Westinghouse P.O. Box 355 Electric Company Pittsburgh, Pennsylvania 15230-0355 USA.

U.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643 Document Control Desk Direct fax: (412)374-3846 Washington, DC 20555-0001 e-mail: greshaja@westinghouse.com AW-10-2940 September 3, 2010 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE

Subject:

LTR-SGMP-10-95 P-Attachment, Rev. 1, "H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions" (Proprietary)

Reference:

Letter from J. A. Gresham to Document Control Desk, LTR-NRC-10-60, dated September 3, 2010 The Application for Withholding Proprietary Information from Public Disclosure is submitted by Westinghouse Electric Company LLC (Westinghouse), pursuant to the provisions of paragraph (b)(1) of Section 2.390 of the Commission's regulations. It contains commercial strategic information proprietary to Westinghouse and customarily held in confidence.

The proprietary material for which withholding is being requested is identified in the proprietary version of the subject report. In conformance with 10 CFR Section 2.390, Affidavit AW-10-2940 accompanies this Application for Withholding Proprietary Information from Public Disclosure, setting forth the basis on which the identified proprietary information may be withheld from public disclosure.

Accordingly, it is respectfully requested that the subject information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.390 of the Commission's regulations.

Correspondence with respect to the proprietary aspects of the application for withholding or the accompanying affidavit should reference AW-10-2940 and should be addressed to J. A. Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.

k A. Gresham, Manager Regulatory Compliance and Plant Licensing Enclosures

AW- 10-2940 AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:

ss COUNTY OF ALLEGHENY:

Before me, the undersigned authority, personally appeared J. A. Gresham, 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:

J. A. Gresham, Manager Regulatory Compliance and Plant Licensing Sworn to and subscribed before me this 3rd day of September 2010 Notary Publ COMMONWEALTH OF PENNSYLVANIA Notarial Seal Cynthia Olesky, Notary Public Manor Boro, Westmoreland County My Commission Expires July 16, 2014 Member. Pennsylvania Association of Notaries

2 AW-10-2940 (1) I am Manager, Regulatory Compliance and Plant Licensing, in Nuclear Services, Westinghouse Electric Company LLC (Westinghouse), and as such, .Ihave 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 Proprietary Information from Public Disclosure accompanying this Affidavit.

(3) [ 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 constitutes Westinghouse policy and provides 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 AW-10-2940 Westinghouse's competitors without license from Westinghouse constitutes a 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 competitive 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 to 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 AW-10-2940 (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 component 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 those 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 confidenceand, 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-SGMP- 10-95 P-Attachment, Rev. 1, "H*: Alternate Leakage Calculation Methods for H* for Situations When Contact Pressure at Normal Operating Conditions Exceeds Contact Pressure at Accident Conditions," (Proprietary) dated September 2010, for submittal to the Commission, being transmitted by Westinghouse letter, LTR-NRC- 10-60, and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk. The proprietary information as submitted by Westinghouse is that associated with technical justification of the H* Alternate Repair Criteria for hydraulically expanded steam generator tubes and may be used only for that purpose.

5 AW-10-2940 This information is part of that which will enable Westinghouse to:

(a) License the H* Alternate Repair Criteria.

Further this information has substantial commercial value as follows:

(a) Westinghouse plans to sell the use of the information to its customers for the purpose of licensing the H* Alternate Repair Criteria.

(b) Westinghouse can sell support and defense of the H* criteria.

(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 to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical justification 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.

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.

PROPRIETARY INFORMATION NOTICE Transmitted herewith are proprietary and/or non-pro'prietary 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 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).

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 interrial 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, order, 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.

Westinghouse Westinghouse Electric Company Nuclear Services P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355 USA U.S. Nuclear Regulatory Commission Direct tel: (412) 374-4643 Document Control Desk Direct fax: (412) 374-3846 Washington, DC 20555-0001 e-mail: greshaja@westinghouse.com Proj letter:

CAW- 10-2943 September 7, 2010 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE

Subject:

LTR-SGMP-10-107 P-Attachment, "Catawba Unit 2: Assessment of Probabilistic Value of H*"

(Proprietary)

The proprietary information for which withholding is being requested in the above-referenced report is further identified in Affidavit CAW- 10-2943 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 the utilization of the accompanying affidavit by Duke Power Company.

Correspondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW-10-2943, and should be addressed to J. A. Gresham, Manager, Regulatory Compliance and Plant Licensing, Westinghouse Electric Company LLC, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.

Very truly yours,

. A. Gresham, Manager Regulatory Compliance and Plant Licensing Enclosures

CAW-10-2943 AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:

ss COUNTY OF ALLEGHENY:

Before me, the undersigned authority, personally appeared J. A. Gresham, 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:

A Gresham, Manager Regulatory Compliance and Plant Licensing Sworn to and subscribed before me this 7th day of September 2010 tary Public COMMONWEALTH OF PENNSYLVANIA Notaial seal CWa Okf, Notary Publk Manor smt, Wagmavg~aij Count M. . J,-, 16, 2014 Mumrier. rnnhlvanMI AaSedetMoV of Notaries

2 CAW-10-2943 (1) I am Manager, Regulatory Compliance and Plant Licensing, 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 2.3 90 of the Commission's regulations and in conjunction with the Westinghouse Application for Withholding Proprietary Information from Public Disclosure accompanying this Affidavit.

(3) 1 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 informationsought 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 constitutes Westinghouse policy and provides 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 aspectsof a process (or component, structure, tool, method, etc.) where prevention of its use by any of

3 CAW- 10-2943 Westinghouse's competitors without license from Westinghouse constitutes a 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 competitive 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 to 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- 10-2943 (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 component 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 those 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-SGMP- 10-107 P-Attachment, "Catawba Unit 2:

Assessment of Probabilistic Value of H*," (Proprietary) dated September 2010, for submittal to the Commission, being transmitted by Duke Power Company letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk. The proprietary information as submitted by Westinghouse is that associated with technical justification of the H* Alternate Repair Criteria for Catawba Unit 2, and may be used only for that purpose.

This information is part of that which will enable Westinghouse to:

(a) License the H* Alternate Repair Criteria.

5 CAW-10-2943 Further this information has substantial commercial value as follows:

(a) Westinghouse plans to sell the use of the information to its customers for the purpose of licensing the H* Alternate Repair Criteria.

(b) Westinghouse can sell support and defense of the H* criteria.

(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 to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical justification 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.

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.

PROPRIETARY INFORMATION NOTICE Transmitted herewith are proprietary and/or non-proprietary 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 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).

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, order, 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.

ATTACHMENT 4 Revised Marked-Up TS Pages

INSERT 1 For Unit 2 only, during the End of Cycle 17 Refueling Outage and subsequent Cycle 18 operation, tubes with service-induced flaws located greater than 20 inches below the top of the tubesheet do not require plugging. Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 20 inches below the top of the tubesheet shall be plugged upon detection.

INSERT 2 For Unit 2, during the End of Cycle 17 Refueling Outage and subsequent Cycle 18 operation, the number and portions of the tubes inspected and method of inspection shall be performed with the objective of detecting flaws of any type (for example, volumetric flaws, axial and circumferential -cracks) that may be present along the length of the tube, from 20 inches below the top of the tubesheet on the hot leg side to 20 inches below the top of the tubesheet on the cold leg side, and that may satisfy the applicable tube repair criteria.

INSERT 3 For Unit 2, during the End of Cycle 17 Refueling Outage and subsequent Cycle 18 operation, if crack indications are found in any SG tube from 20 inches below the top of the tubesheet on the hot leg side to 20 inches below the top of the tubesheet on the cold leg side, then the next inspection for each SG for the degradation mechanism that caused the crack indication shall not exceed 24 EFPM or one refueling outage (whichever is less).

INSERT 4 In addition, if the calculated accident leakage rate from the most limiting accident is less than 3.27 times the maximum primary to secondary LEAKAGE rate, the report shall describe how it was determined, and INSERT 5

j. For Unit 2, following completion of an inspection performed during the End of Cycle 17 Refueling Outage (and any inspections performed during subsequent Cycle 18 operation), the results of monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided.

(2) Technical Specifications The Technical S ifications contained in Appendix A, as revised through Amendment No ,shich are attached hereto, are hereby incorporated' into this renewed operating license. Duke Energy Carolinas, LLC shall operate the facility in accordance with the Technical Specifications.

(3) Updated Final Safety Analysis Report The Updated Final Safety Analysis Report supplement submitted pursuant to 10 CFR 54.21(d), as revised on December 16, 2002, describes certain future activities to be completed before the period of extended operation. Duke shalt complete these activities no later than February 24, 2026, and shall notify the NRC in writing when implementation of these activities is complete and can be verified by NRC inspection.

The Updated Final Safety Analysis Report supplement as revised on December 16, 2002, described above, shall be included in the next scheduled update to the Updated Final Safety Analysis Report required by 10 CFR 50.71(e)(4), following issuance of this renewed operating license. Until that update is complete, Duke may make changes to the programs described in such supplement without prior Commission approval, provided that Duke evaluates each such change pursuant to the criteria set forth in 10 CFR 50.59 and otherwise complies with the requirements in that section.

(4) Antitrust Conditions Duke Energy Carolinas, LLC shall comply with the antitrust conditions delineated in Appendix C to this renewed operating license.

(5) Fire Protection Proaram (Section 9.5.1, SER, SSER #2, SSER #3, SSER #4, SSER #5)*

Duke Energy Carolinas, LLC shall implement and maintain in effect all provisions of the approved fire protection program as described in the Updated Final Safety Analysis Report, as amended, for the facility and as approved in the SER through Supplement 5, subject to the following provision:

The licensee may make changes to the approved fire protection program without prior approval of the Commission only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.

• The parenthetical notation following the title of this renewed operating license condition denotes the section of the Safety Evaluation Report and/or its supplements wherein this renewed license condition is discussed.

Renewed License No. NPFr,)

Amendment No. is,

(6) Mitigation Strategies Develop and maintain, strategies for addressing large fires and explosions and that include the following key areas:

(a) Fire fighting. response strategy with the following elements:

1. Pre-defined coordinated fire response strategy and guidance

2. Assessment of mutual. aid fire fighting assets

3. Designated staging; areas for equipment and materials 4.. Command and, control

5. Training of response personnel (b) Operations to mitigate fuel; damage considering. the following:

1. Protection and use of personnel assets

2. Communications

3. Minimizing fire spread

4. Procedures for implementing integrated fire response strategy

5. Identification of readily-available pre-staged equipment

6. Training on integrated fire response strategy

7. Spent fuel pool mitigation measures (c) Actions to minimize release to include consideration of:

1. Water spray scrubbing

2. Dose to onsite responders (7) Additional Conditions The Additional Co igitions contained; in Appendix B,. as revised through Amendment No.(-W are hereby incorporated into this renewed operating license. Duke Energy Carolinas, LLC shall operate the facility in accordance with the Additional Conditions.

D. The facility requires exemptions from certain requirements of Appendix J to 10 CFR Part 50, as delineated below and pursuant-to evaluations contained in the referenced SER and SSERs. These include, (a) partial, exemption from the requirement of paragraph Ut0D12(bXii) of Appendix J, the testing of containment airlocks at times when the containment integrity is not required (Section-6.2.6 of the-SER, and SSERs # 3 and #4).

(b) exemption from the requirement of paragraph IIl.A.(d) of Appendix J, insofar as it requires the venting and draining of lines for type A tests (Section 6.2.6 of SSER #3), and (c) partial exemption from the requirements of paragraph 111.1 of Appendix J, as it relates to bellows testing (Section 6.2.6 of the SER and SSER #3). These exemptions are authorized by law, will not present an undue risk to the public health and safety, are consistent Renewed License No. NPF-52 Amendment No.

Amendment ' Implementation Number Additional Condition Date 165 The schedule for the performance of new and By January 31, 1999 revised surveillance requirements shall be as follows:

For surveillance requirements (SRs) that are new in Amendment No. 165 the first performance is due at the end of the first surveillance interval that begins at implementation of Amendment No. 165. For SRs that existing prior to Amendment No. 165, including SRs with modified acceptance criteria and SRs who intervals of performance are being extended, the first performance is due at the end of the first surveillance interval that begins on the date the surveillance was last performed prior to implementation of amendment No. 165. For SRs that existed prior to Amendment No. 165, whose intervals of performance are being reduced, the first reduced surveillance interval begins upon completion of the first surveillance performed after implementation of Amendment No. 165 orseam generato G) inegrity or any e assessments, th ratio of 2.5 will be ed in into ode 4udng completion o oth the Condition onitoring le417 o eratio (CM) and e Opemtion I Assis ment (OA) upon i ;lementation of the fterim Alternate Re ;ir Criterion (IARC)X./or example, for the from the lowerr hso the most limitin G during the p * ~cycle of operation will be multiplied* a factor of 2.5 and add to the

(** total leage to the co ~S~red fromallowable any otheracsour i ent and analysis

• eakage assumption. ForJ CIA, the difference in leakage frr the allowable limit during the limiting d ign basis accident mi s the leakage fro fe other sources will b*

divided by 2. nd compared to the ob rved leakage. 'aministrative limit will e establi'e*dto not exceed the ca lated value_

Renewed License No. NPF-52 Amendment No.

NO CHANGES THIS PAGE.

FOR INFORMATION ONLY Programs and Manuals 5.5 5.5 Programs and Manuals (continued) 5.5.8 Inservice Testing Proaram This program provides controls for inservice testing of ASME Code Class 1, 2, and 3 components including applicable supports. The program shall include the following:

a. Testing frequencies applicable to the ASME Code for Operations and Maintenance of Nuclear Power Plants (ASME OM Code) and applicable Addenda as follows:

ASME OM Code and applicable Required Frequencies for Addenda terminology for performing inservice testing inservice testinq activities activities Weekly At least once per 7 days Monthly At least once per 31 days Quarterly or every 3 months At least once per 92 days Semiannually or every 6 mpnths At least once per 184 days Every 9 months At least once per 276 days Yearly or annually At least once per 366 days Biennially or every 2,years At least once per 731 days

b. The provisions of SR 3.0.2 are applicable to the above required Frequencies and to other normal and accelerated Frequencies specified as 2 years or less for performing inservice testing activities;

c. The provisions of SR 3.0.3 are applicable to inservice testing activities; and

d. Nothing in the ASME OM Code shall be construed to supersede the requirements of any TS.

5.5.9 Steam Generator (SG) Program A Steam Generator Program shall be established and implemented to ensure that SG tube integrity is maintained. In addition; the Steam Generator Program shall include the following provisions:

a. Prpvisions for condition monitoring assessments. Condition monitoring assessment means an evaluation of the "as found" condition of the tubing with respect to the performance criteria for structural integrity and accident induced leakage. The "as found" condition refers to the (continued)

Catawba Units 1 and 2 5.5-6 Amendment Nos. 252, 247

O*CHANGES THIS PACE.] Programs and Manuals FOR lNrORATIO,%ONLY 5.5 Programs and Manuals 5.5.9 Steam Generator (SG) Program (continued) condition of the tubing during a SG inspection outage, as determined from the inservice inspection results or by other means, prior to the plugging of tubes. Condition monitoring assessments shall be conducted during each outage during which the SG tubes are inspected or plugged to confirm that the performance criteria are being met.

b. Performance criteria for SG tube integrity. SG tube integrity shall be maintained by meeting the performance criteria for tube structural integrity, accident induced leakage, and operational LEAKAGE.

1. Structural integrity performance criterion: All inservice SG tubes shall retain structural integrity over the full range of normal operating conditions (including startup, operation in the power range, hot standby, and cooldown, and all anticipated transients

'included in the design specification) and design basis accidents.

This includes retaining a safety factor of 3.0 against burst under normal steady state full power operation primary to secondary pressure differential and a safety factor of 1.4 against burst applied to the design basis accident primary to secondary pressure differentials. Apart from the above requirements, additional loading conditions associated with the design basis accidents, or combination of accidents in accordance with the design and licensing basis, shall also be evaluated to determine if the associated loads contribute significantly to burst or collapse.

In the assessment of tube integrity, those loads that do significantly affect burst or collapse shall be determined and assessed in combination with the loads due to pressure with a safety factor of 1.2 on the combined primary loads and 1.0 on axial secondary loads.

2. Accident induced leakage performance criterion: The primary to secondary accident induced leakage rate for any design basis accident, other than a SG tube rupture, shall not exceed the leakage rate assumed in the accident analysis in terms of total leakage rate for all SGs and leakage rate for an individual SG.

Leakage is not to exceed 150 gallons per day through each SG for a total of 600 gallons per day through all SGs.

3. The operational LEAKAGE performance criterion is specified in LCO 3.4.13, "RCS Operational LEAKAGE."

c. Provisions for SG tube repair criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding 40% of the nominal tube wall thickness shall be plugged.

(continued)

Catawba Units 1 and 2 5.5-7 Amendment Nos. 218/212

• Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.9 Steam Generator (SG) Program (continued)

The following SG tube alternate repair criteria shall be applied as an alternative to the 40% depth based criteria:

1. For the Unit 2 End Cycle 16 Refueling 0 age and subsequent Cycle 17 oper a n only, tubes with flaw aving a circumferential component ss than or equal to 203 egrees found in the portion of the t below 17 inches from e top of the tubesheet and ab 1 inch from the bottom the tubesheet do not require ugging. Tubes with fla aving a circumferential compon greater than 203 degr found in the portion of the tube low 17 inches fromthe p of the tubesheet and above 1 , h from the bottom of the t sheet shall be removed from s ice.

Tubes service-induced flaws located hin the region from the t of the tubesheet to 17 inches ow the top of the t sheet shall be removed from ice. Tubes with service-induced axial cracks found in t portion of the tube below 17 inches from the top of the esheet do not require plugging.

When more than o law with circumferential comprn nts is found in the po n of the tube below 17 inchesfm the top of IM1SeirY I the tubeshe and above 1 inch from the bo of the tubesheet with the al of the circumferential com ents greater than 203 deg s and an axial separaion di -e of less than 1 inch, then tube shall be removed fro rvice. When the circumferential components of each of the ws are added, it is acceptable to count the overlapped ions only once in the total of circumferential co nents.

When one more flaws with circumferential co nents are found i e portion of the tube within 1 inch m the bottom of the esheet, and the total of the circ rential components und in the tube exceeds 94 degr ,then the tube shall be removed from service. When e or more flaws with circumferential compone are found in the portion of the tube within 1 inch from the ttom of the tubesheet and within 1 inch axial separation ance of a flaw above 1 inch from the bott of the tube e and the total of the circumferential com ents found in tube exceeds 94 degrees, then the tube all be rem d from service. When the circumferenti , mponents of ch of the flaws are added, it is acceptabl count the overlappedportions onyce in the t of circumferential components.

(continued)

Catawba Units 1 and 2 5,5-7a Amendment No.0

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.91 Steam Generator (SG) Program (continued) ' (,J*" i, t-*'

d. Provisions for S ube inspections. Periodic SG tube inspections shall be performed. num er an portions of the tubes inspected and method of inspection shall be performed with the objective of detecting flaws of any type (for example, volumetric flaws, axial and circumferential cracks) that may be present along the length of the tube, from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet, and that may satisfy the applicable tube repair criteria. The tube-to-tubesheet weld is not part of the tube. In addition to meeting requirements d.1, d.2, d.3, and d.4 below, the inspection scope, 1, J"'wr ..T -;"ý inspection methods, and inspection intervals shall be such as to ensure that SG tube integrity is maintained until the next SG inspection. An assessment of degradation shall be performed to determine the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations.

1. Inspect 100% of the tubes in each SG during the first refueling outage following SG replacement.

2. For Unit 1, inspect 100% of the tubes at sequential periods of 144,108, 72, and, thereafter, 60 Effective Full Power Months (EFPM). The first sequential period shall be considered to begin after the first inservice inspection of the SGs. In addition, inspect 50% of the tubes by the refueling outage nearest the midpoint of the period and the remaining 50% by the refueling outage nearest the end of the period. No SG shall operate for more than 72 EFPM or three refueling outages (whichever is less) without being inspected.

3. For Unit 2, inspect 100% of the tubes at sequential periods of 120, 90, and, thereafter, 60 EFPM. The first sequential period shall be considered to begin after the first inservice inspection of the SGs. In addition, inspect 50% of the tubes by the refueling outage nearest the midpoint of the period and the remaining 50%

by the refueling outage nearest the end of the period. No SG shall operate for more than 48 EFPM or two refueling outages (whichever is less) without being inspected.

- 4. rack indications are found in any SG tube, then the next inspection for each SG for the degradation mechanism that caused the crack indicatior shall not exceed 24 EFPM or one refuelin outa e whichever is less). If definitive information, such as from examination of a pu le tu e, diagnostic non-destructive testing, or engineering evaluation indicates that a crack-like indication is not associated with crack(s), then the indication need (continued)

Catawba Units 1 and 2 5.5-8 Amendment Nos.

LN AA N ,CHHAE IPS 5.5G 0PNONLY Programs and Manuals5.5 5.5 Programs and Manuals 5.5.9 Steam Generator (SG) Program (continued) not be treated as a crack.

e. Provisions for monitoring operational primary to secondary LEAKAGE.

5.5.10 Secondary Water Chemistry Program This program provides controls for monitoring secondary water chemistry to inhibit SG tube degradation and low pressure turbine disc, stress corrosion cracking. The program shall include:

a. Identification of a sampling schedule for the critical variables and control points for these variables;

b. Identification of the procedures used to measure the values of the critical variables;

c. Identification of process sampling points, which shall include monitoring the discharge of the condensate pumps for evidence of condenser in leakage;

d. Procedures for the recording and management of data;

e. Procedures defining corrective actions for all off control point chemistry conditions; and

f. A procedure identifying the authority responsible for the interpretation of the data and the sequence and timing of administrative events, which is required to initiate corrective action.

5.5.11 Ventilation Filter Testing Proaram (VFTP)

A program shall be established to implement the following required testing of Engineered Safety Feature (ESF) filter ventilation systems in accordance with Regulatory Guide 1.52, Revision 2, and ANSI N510-1980, with exceptions as noted in the UFSAR.

a. Demonstrate for each of the ESF systems that an inplace test of the high efficiency particulate air (HEPA) filters shows the following penetration and system bypass when tested in accordance with Regulatory Guide 1.52, Revision 2, and ANSI N510-1980 at the flowrate specified below +/- 10%.

(continued)

, Catawba Units 1 and 2 5.5-9 Amendment Nos. 218/212

Reporting Requirements 5.6 5.6 Reporting Requirements (continued) 5.6.7 PAM Report When a report is required by LCO 3.3.3, "Post Accident Monitoring (PAM)

Instrumentation," a report shall be submitted within the following 14 days. The report shall outline the preplanned alternate method of monitoring, the cause of the inoperability, and the plans and schedule for restoring the instrumentation channels of the Function to OPERABLE status.

5.6.8 Steam Generator (SG) Tube Inspection Report A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of the inspection. The report shall include:

a. The scope of inspections performed on each SG,

b. Active degradation mechanisms found,

c. Non-destructive examination techniques utilized for each degradation mechanism,

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications,

e. Number of tubes plugged during the inspection outage for each active degradation mechanism,

f. Total number and percentage of tubes plugged to date, I

g. The results of condition monitoring, including the results of tube pulls and in-situ testing, I (continued)

Catawba Units 1 and.2 5.6-5 Amendment Nos. 222,0

Reporting Requirements 5.6 5.6 Reporting Requirements 5.6,8 Steam Generator (SG) Tube Inspection Report (continued)

For Unit 2, foll completion of an inspection performed during the End of Cycle aRefueling Outage (and any inspections performed during subsequent C cle operation), the primary to secondary LEAKAGE rate observe~d in each SG (if it is not practical to assign leakage to an individual SG, the entire primary to secondary LEAKAGE should be conservatively assumed to be from one SG) durinthe cycle preceding the inspection which is the subject of the report,6,a)

For Unit 2, followin completion of an inspection performed during the

.(D-- End of Cycle Refueling Outage (and any inspections performed during subse uent C cle operation), the calculated accident leakage rate from the portion of the tubes below . inches from the top of the tubesheet for the most limiting accident in the most limiting SG.

Catawba Units 1 and 2 5.6-6 Amendment Nos. 222/01