ML022110334

WCAP-15047, Revision 2, D.C. Cook Unit 2 WOG Reactor Vessel 60-Year Evaluation Minigroup Heatup and Cooldown Limit Curves for Normal Operation

ML022110334
Person / Time
Site:	Cook
Issue date:	05/31/2002
From:	Charles Brown, Gresham J Westinghouse
To:	Office of Nuclear Reactor Regulation
References
AEP:NRC:2349-01, FOIA/PA-2005-0108 WCAP-15047, Rev 2
Download: ML022110334 (61)

Text

WESTINGHOUSE NON-PROPRIETARY CLASS 3 D.C. Cook Unit 2 WOG Reactor Vessel 60-Year Evaluation Minigroup Heatup and Cooldown Limit Curves for Normal Operation Westinghouse Electric Company LLC

PAGE 03/04 06/@5/2002 14:47 412-374-4@11 WESTIN.GHOUSE NONI-PROPI'ETAIRY CLASS 3 WCAP-15047, Revision 2 D.C. Cook Unit 2 WOG Reactor Vessel 60-Year Evaluation Minigroup Heatup and Cooldown Limit Curves For Normal Operation Cherryl Brown May 2002 Prepared by the Westinghouse Electric Company LLC for the WOG Reactor Vessel 60-Year Evaluation N.finigroup 3A. G-reshani, Manager Equipment & Materials Technology WESTlNýGHOUSE ELECTRIC COMPANY LLC P.O. Box 355 Pittsburgh, Pernsylvaria 15230-0355

© 2002 Westinghouse Electric Company LLC All Rithts Reserved W EC-LICENSING

. I LEGAL NOTICE This report was prepared by Westinghouse as an account of work sponsored by the Westinghouse Owners Group (vVOG). Neither the WOG. any member of the WOG, Westinghouse, nor any person acting on behalf of any of themr (A)

Makes any warranty or representation whatsoever, express or implied, (I) with respect to the use of any information, apparatus. method, process, or similar item disclosed in this report, including merchantability and fitness for a particular purpose, (II) that such use does not infringe on or interfere with privately owned rights, including any party's intellectual property., or (III) that this report is suitable to any particular user's circumstance; or (B)

Assumes responsibility for any damages or other liability whatsoever (including any consequential damages, even if the WOG or any WOG representative has been advised of the possibility of such damages) resulting from any selection or use of this report or any information, apparatus, method, process, or similar item disclosed in this report.

PREFACE This report has been technically reviewed and verified by:

T. Laubham i/'nI Revision 1:

An error was detected in the "OPERLIM" Computer Program that Westinghouse uses to generate pressure-temperature (PT) limit curves (Documented in NSAL Letter NSAL-0 1-004, "Pressure/Temperature Limit Curves", Dated May 2, 2001). This error potentially effects the heatup curves when the 1996 Appendix G Methodology is used in generating the PT curves. It has been determined that WCAP-15047 Rev. 0 was impacted by this error. Thus, this revision provides corrected curves from WCAP-15047 Rev. 0.

Note that only the heatup curves and associated data points tables in Section 9 have changed. The cooldown curves and data points remain valid and were not changed.

Revision 2:

The PT curves documented in Revisions 0 and 1 were based on "best estimate" fluences. WCAP-135 15 was revised to update the fluence methodology (ie. Reg. Guide 1. 190) and to include the "calculated" fluences. Thus, this report was revised to incorporate the "calculated" fluences into the D.C. Cook Unit 2 PT curves. In addition to this change, the PT curves were also updated to incorporate the use of the methodology from the 1995 ASME Code Section XI through the 1996 Addenda, Appendix G and Code Case N-64 1, which allows the use of K:c for PT Curve Generation and alternative methods for calculating the enable temperature (Section 10. 0). Text has been updated to support the use of the '96 App. G and Ki.

methodologies.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

ii TABLE OF CONTENTS LIST OF TABLES iv LIST OF FIGURES vi

1.0 INTRODUCTION

1-1 2.0 PURPOSE 2-1 3.0 CRITERL-k FOR ALLOWABLE PRESSURE-TEMPERATURE RELATIONSHIPS 3-1 4.0 CHEMISTRY FACTOR DETERMINATION 4-1 4.1 Chemistrv Factor Methodolopy 4-1 4.1.1 Application of the Ratio Procedure 4-2 4.1.2 Temperature Effects on Surveillance Data 4-2 4.2 Surveillance Program Credibility Evaluation 4-5 4.2.1 Application of the Credibility Criteria 4-12 4.2.2 ca and How it was Determined 4-12 5.0 UNIRRADL-kTED PROPERTIES 5-1 5.1 Initial RTCT of Beltlme Materials 5-1 5 2 Determination of ai 5-2 5.3 Bolt-up Temperature 5-2 6.0 REACTOR VESSEL GEOMETRIC & SYSTEM PARAMMETERS 6-1 6.1 Reactor Vessel Physical Dimensions and Operating Conditions 6-1 7.0 FLUENCE FACTOR DETERMINATION 7-1

7. 1 Peak Clad Base Metal Interface Fluence for each Beltline Material 7-1 7.2 1/4T & 3/4T Thickness Fluence for each Beltline Material 7-2 7.3 Fluence Factors 7-2 D.C. Cook Unit 2 Hearup and Cooldown Limit Curves

TABLE OF CONTENTS - (Continued) 8.0 CALCULATION OF ADJUSTED REFERENCE TEMPERATURE 8.1 Methodology 8.2 Adjusted Reference Temperature (ART) Calculations 9.0 HEATUP AND COOLDOWN PRESSURE-TEMPERATL-RE LIMIT CURVES

9. 1 Introduction and Methodology 10.0 ENABLE TEMPERATURE C.ALCULATIONS 10.1 ASME Code Case N-641 Methodology 10.2 32 EFPY Enable Temperature 10.3 48 EFPY Enable Temperature 11 REFERENCES DC. Cook Unit 2 Heatup and Cooldown Limit Curves iii 8-1 8-1 8-2 9-1 9-1 10-1 10-1 10-1 10-2 11-1

iv LIST OF TABLES 4-1 Reactor Vessel Beltline Material Copper and Nickel Content and Calculated CF 4-3 4-2 Calculation of Chemistry Factors using Cook Unit 2 Surveillance Capsule Data 4-4 4-3 Calculation of Chemistry Factors using Cook Unit 2 Surveillance Capsule Data 4-9 4-4 Cook Unit 2 Surveillance Capsule Data Scatter about the Best-Fit line for the 4-10 Weld Material 4-5 Cook Unit 2 Surveillance Capsule Data Scatter about the Best-Fit line for the 4-11 Intermediate Shell Plate C552 1-2 Material 5-1 Reactor Vessel Beltline Material Description 5-1 7-1 Best-Estimate Fluence (1019 n/cm, E > 1.0 MeV) at the Pressure Vessel 7-1 Clad/Base Metal Interface for the Cook Unit 2 Reactor Vessel 7-2 Summary of Fluence Values Used to Calculate the Cook Unit 2 ART Values 7-2 7-3 Summary of Fluence Values Used to Calculate the Cook Unit 2 ART Values 7-3 8-1 Calculation of the ART Values for the 1/4T Location and 32 EFPY 8-3 8-2 Calculation of the ART Values for the 3/4T Location and 32 EFPY 8-4 8-3 Calculation of the ART Values for the 1/4T Location and 48 EFPY 8-5 8-4 Calculation of the ART Values for the 3/4T Location and 48 EFPY 8-6 8-5 Summary of the Limiting ART Values to be Used in the Generation of the 8-7 Cook Unit 2 Reactor Vessel Heatup and Cooldown Curves 9-1 D.C. Cook Units 2 Reactor Vessel Heatup Curve Data Points for 32 EFPY 9-7 Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150 0 F and 621 psi per 10CFR50)

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

V LIST OF TABLES - (Continued) 9-2 D.C. Cook Unit 2 Reactor Vessel Cooldown Curve Data Points for 32 EFPY 9-8 Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFR50) 9-3 D.C. Cook Unit 2 Reactor Vessel Heatup Cur-ve Data Points for 48 EFPY 9-9 Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFR50) 9-4 D.C. Cook Unit 2 Reactor Vessel Cooldown Curve Data Points for 48 EFPY 9-10 Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFRSO)

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

vi LIST OF FIGURES 9-1 D.C. Cook Unit 2 Reactor Coolant System Heatup Limitations (Heatup Rate 9-3 of 600F,/hr) Applicable for 32 EFPY (Without Margins for Instrumentation Errors)

(Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFRS0) 9-2 D.C. Cook Unit 2 Reactor Coolant System Cooldovxrn Limitations (Cooldown Rates 9-4 of 0, 20, 40, 60 and OOOF/'hr) Applicable for 32 EFPY (Without Margins for Instrumentation Errors) (Includes Vessel Flange Requirements of 150 0F and 621 psi per 10CFR50) 9-3 D.C. Cook Unit 2 Reactor Coolant System Heatup Limitations (Heatup Rate 9-5 of 60°F/hr) Applicable for 48 EFPY (Without Margins for Instrumentation Errors)

(Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFR50) 9-4 D.C. Cook Unit 2 Reactor Coolant System Cooldown Limitations (Cooldown Rates 9-6 of 0, 20, 40, 60 and 100°F/hr) Applicable for 48 EFPY (Without Margins for Instrumentation Errors) (Includes Vessel Flange Requirements of 150OF and 621 psi per 10CFR50)

D.C. Cook Umt 2 Heatup and Cooldown Limit Curves

1-1

1.0 INTRODUCTION

Heatup and cooldown limit curves are calculated using the adjusted RTNT (reference nil-ductility temperature) corresponding to the limiting beltline region material of the reactor vessel.

The adjusted RTNcT of the limiting material in the core region of the reactor vessel is determined by using the unirradiated reactor vessel material fracture toughness properties, estimating the radiation-induced ART\\,yT, and adding a margin. The unirradiated RTN-: is designated as the higher of either the drop weight nil-ductility transition temperature (NDTT) or the temperature at which the material exhibits at least 50 ft-lb of impact energy and 35-mil lateral expansion (normal to the major working direction) minus 60°F RT,,I-T increases as the material is exposed to fast-neutron radiation. Therefore, to find the most limiting RTN.DT at any time period in the reactor's life, ART>MoT due to the radiation exposure associated with that time period must be added to the unirradiated RT>,F-T (IRTN-DT).

The extent of the shift in RT,,j-n is enhanced by certain chemical elements (such as copper and nickel) present in reactor vessel steels. The Nuclear Regulatory Commission (NRC) has published a method for predicting radiation embrittlement in Regulatory Guide 1.99, Revision 2, "Radiation Embrittlement of Reactor Vessel Materials['.1 Regulatory Guide 1.99, Revision 2, is used for the calculation of Adjusted Reference Temperature (ART) values (IRTNrDT + ARTMT + margins for uncertainties) at the l/4T and 3/4T locations, where T is the thickness of the vessel at the beltline region measured from the clad/base metal interface.

The heatup and cooldown curves documented in this report were generated using the most limiting ART values and the NRC approved methodology documented in WCXP-14040-NP-A, Revision 2"",

"Methodology Used to Develop Cold Overpressure Mitigating System Setpoints and RCS Heatup and Cooldown Limit Curves" with exception of the following: 1) The fluence values used in this report are calculated fluence values (i.e. comply with Reg. Guide 1.190), not the best estimate fluence values. 2)

The K:c critical stress intensities are used in place of the Kia critical stress intensities. This methodology is taken from approved ASME Code Case N-64 1 31 (which covers Code Cases N-64011 ). 3) The 1996 Version of Appendix G to Section XI[31 will be used rather than the 1989 version.

DC. Cook Unmt 2 Heatup and Cooldown Limt Curves

2.0 PURPOSE D.C. Cook Unit 2, as members of the WOG Reactor Vessel 60-year Mini-group, has contracted Westinghouse to generate new heatup and cooldown curves for the current end of license and life extension.

The D.C. Cook Unit 2 heatup and cooldown curves were generated without margins for instrumentation errors.

The curves include a hydrostatic leak test limit curve from 2485 to 2000 psig and pressure temperature limits for the vessel flange regions per the requirements of 10 CFR Part 50, Appendix Gr1.

The purpose of this report is to present the calculations and the development of D.C. Cook Unit 2 heatup and cooldowvn curves for the current end of license and license renewal.

This report documents the calculated adjusted reference temperature (ART) values following the methods of Regulatory Guide 1.99, Revision 2{1, for all the beltline materials and the development of the heatup and cooldown pressure temperature limit curves for normal operation.

D.C. Cook Unrt 2 Heatup and Cooldown Limit Curves

3-1 3.0 CRITERLI FOR.LLOWXBLE PRESSURE-TEMPERATURE RELATIONSHIPS 3.1 Overall Approach Appendix G to 10 CFR Part 50, "Fracture Toughness Requirements'(2] specifies fracture toughness requirements for ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of safety during any condition of normal operation, including anticipated operational occurrences and system hydrostatic tests, to which the pressure boundary may be subjected over its service lifetime. The ASME Boiler and Pressure Vessel Code forms the basis for these requirements.

Section XI, Division 1, "Rule for Inservice Inspection of Nuclear Power Plant Components", Appendix G{31, contains the conservative methods of analysis.

The ASME approach for calculating the allowable limit curves for various heatup and cooldown rates specifies that the total stress intensity factor, Kr, for the combined thermal and pressure stresses at any time during heatup or cooldown cannot be greater than the reference stress intensity factor, Ki,, for the metal temperature at that time.

Ki is obtained from the reference fracture toughness curve, defined in Code Case N-641 of Appendix G of the ASME Code,Section XI. The Kic curve is given by the following equation:

K- = 33.2 + 20.734

• e'o(RTvr,](1)

where, Kic =

reference stress intensity factor as a function of the metal temperature T and the metal reference nil-ductility temperature RTNDT This Ki. curve is based on the lower bound of static K1 values measured as a function of temperature on specimens of SA-533 Grade B Class 1. SA-508-1. SA-508-2, and SA-508-3 steels-D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

3-2 3.2 Methodology for Pressure-Temperature Limit Curve Development The governing equation for the heatup-cooldow-n analysis is defined in Code Case N-640 of Appendix G of the ASME Code as follows:

C

• K i Kr, < K,c (2)

where, KLn

=

stress intensity factor caused by membrane (pressure) stress Ki,

=

stress intensity factor caused by the thermal gradients Ki

=

function of temperature relative to the RTN-DT of the material C

=

2.0 for Level A and Level B service limits C

=

1.5 for hydrostatic and leak test conditions during which the reactor core is not critical For membrane tension, the Ki corresponding to membrane tension for the postulated defect is:

KLnMm * (pR, + t)

(3)

Where Mm, for an inside surface is given by:

Mm = 1.85 for "it < 2, NI = 0.926,it for 2 _< \\'t < 3.464, and NmI = 3.2 1 for 4t > 3.464.

Similarly. Mm for an outside surface flaw is given by:

Mm = 1.77 for q't < 2, Mm = 0.893 1't for 2 _< 't < 3.464, and Mm = 3.09 for,t > 3.464.

Where:

Ri = vessel inner radius.

t = vessel wall thickness, and p internal pressure, DC. Cook Unit 2 Heatup and Cooldown Limit Curves

• 0*

For Bending Stress, the K, corresponding to bending stress for the postulated defect is:

Krb = %lb

• maximum bending stress, where Mb is two-thirds of Mm For the Radial Thermal Gradient, the maximum K; produced by radial thermal gradient for the postulated inside surface defect is:

Ki, = 0.953x10"3 x CR x t15 (4) whereý CR = the cooldown rate in OF/hr.

For the Radial Thermal Gradient, the maximum K1 produced by radial thermal gradient for the postulated outside surface defect is:

Ki, = 0.753x10"3 x HU x t 5 (5) where:

HU = the heatup rate in OF/hr.

The through-wall temperature difference associated with the maximum thermal K1 can be determined from ASME Section XI, Appendix G, Figure G-2214-1. The temperature at any radial distance from the vessel surface can be determined from ASME Section XI, Appendix G. Figure G-2214-2 for the maximum thermal K1.

(a) The maximum thermal K1 relationship and the temperature relationship in Fig. G-2214-1 are applicable only for the conditions given in G-22 14.3 (a)(1) and (2) of Appendix G to ASME Section XM.

(b) Altemativelv. the K1 for radial thermal gradient can be calculated for any thermal stress distribution and at any specified time during cooldown for a 'i,-thickness inside surface defect using the relationship:

K.,, = (1.0359Ca + 0.6322CI - 0.4753C: - 0.3855C3)

(6) or similarly, KIT during heatup for a 1/44-thickness outside surface defect using the relationship:

DC. Cook Unit 2 Hearup and Cooldown Limit Curves

3-4 K, = (1.043C +-0 630C +0.481C2 +/- 0.401C3) *

,-t (7) where the coefficients Co. C:, C: and C3 are determined from the thermal stress distribution at any specified time during the heatup or cooldown using the form:

o(X) = Co + CI(x / a) + C:(x / a) 2 + C3(x / a)3 (8) and x is a variable that represents the radial distance from the appropriate (i.e., inside or outside) surface to any point on the crack front and a is the maximum crack depth.

Note, that equations 3 through 8 were added to the OPERLIM computer program, which is the Westinghouse computer program used to generate pressure-temperature limit curves. No other changes were made to the OPERLIM computer program with regard to the pressure-temperature curve calculation methodology. Hence, the pressure-temperature curve methodology described in WCAP-14O40410 ' Section 2.6 (equations 2.6.2-4 and 2.6.3-1) remains valid for the generation of the pressure-temperature curves documented in this report with the exceptions described above.

At any time during the heatup or cooldown transient, Kic is determined by the metal temperature at the tip of a postulated flaw at the /,%T and %/ýT location, the appropriate value for RT.,Tou and the reference fracture toughness curve. The thermal stresses resulting from the temperature gradients through the vessel wall are calculated and then the corresponding (thermal) stress intensity factors, Kit, for the reference flaw are computed.

From Equation 2I the pressure stress intensity factors are obtained and, from these, the allowable pressures are calculated.

For the calculation of the allowable pressure versus coolant temperature during cooldown, the reference flaw of Appendix G to the ASME Code is assumed to exist at the inside of the vessel wall.

During cooldown, the controlling location of the flaw is always at the inside of the wall because the thermal gradients produce tensile stresses at the inside, which increase with increasing cooldown rates. Allowable pressure-temperature relations are generated for both steady-state and finite cooldown rate situations.

From these relations, composite limit curves are constructed for each cooldown rate of interest.

D.C. Cook Unit 2 Heatup and Cooldovwn Limit Curves

_-5 The use of the composite curve in the cooldown analysis is necessary because control of the cooldown procedure is based on the measurement of reactor coolant temperature. whereas the limiting pressure is actually dependent on the material temperature at the tip of the assumed flaw. During cooldown, the 1/4T vessel location is at a higher temperature than the fluid adjacent to the vessel inner diameter.

This condition, of course, is not true for the steady-state situation. It follows that, at any given reactor coolant temperature, the AT (temperature) developed during cooldown results in a higher value of Kic at the 1/T location for finite cooldown rates than for steady-state operation. Furthermore, if conditions exist so that the increase in Kic exceeds Kit, the calculated allowable pressure during cooldown will be greater than the steady-state value.

The above procedures are needed because there is no direct control on temperature at the V'T location and, therefore, allowable pressures may unknowingly be violated if the rate of cooling is decreased at various intervals along a cooldown ramp. The use of the composite curve eliminates this problem and ensures conservative operation of the system for the entire cooldown period.

Three separate calculations are required to determine the limit curves for finite heatup rates. As is done in the cooldown analysis, allowable pressure-temperature relationships are developed for steady-state conditions as well as finite heatup rate conditions assuming the presence of a V4T defect at the inside of the wall. The heatup results in compressive stresses at the inside surface that alleviate the tensile stresses produced by internal pressure.

The metal temperature at the crack tip lags the coolant temperature; therefore, the Kic for the VJT crack during heatup is lower than the Kic for the 1/4/T crack during steady-state conditions at the same coolant temperature.

During heatup, especially at the end of the transient, conditions may exist so that the effects of compressive thermal stresses and lower Kic values do not offset each other, and the pressure-temperature curve based on steady-state conditions no longer represents a lower bound of all similar curves for finite heatup rates when the 'AT flaw is considered.

Therefore, both cases have to be analyzed in order to ensure that at any coolant temperature the lower value of the allowable pressure calculated for steady-state and finite heatup rates is obtained.

The second portion of the heatup analysis concerns the calculation of the pressure-temperature limitations for the case in which a '/T flaw located at the '"J location from the outside surface is assumed. Unlike the situation at the vessel inside surface, the thermal gradients established at the outside surface during heatup produce stresses which are tensile in nature and therefore tend to reinforce any pressure stresses present.

These thermal stresses are dependent on both the rate of heatup and the time (or coolant temperature) along D.C. Cook Unit 2 Heatup and Cooldown Lirrut Curves

3-6 the heatup ramp Since the thermal stresses at the outside are tensile and increase with increasing heatup rates, each heatup rate must be analyzed on an individual basis.

Following the generation of pressure-temperature curves for both the steady state and finite heatup rate situations, the final limit curves are produced by constructing a composite curve based on a point-by-point comparison of the steady-state and finite heatup rate data.

At any given temperature, the allowable pressure is taken to be the lesser of the three values taken from the curves under consideration. The use of the composite curve is necessarv to set conservative heatup limitations because it is possible for conditions to exist wherein, over the course of the heatup ramp, the controlling condition switches from the inside to the outside, and the pressure limit must at all times be based on analysis of the most critical criterion.

10 CFR Part 50, Appendix G addresses the metal temperature of the closure head flange and vessel flange regions. This rule states that the metal temperature of the closure flange regions must exceed the material unirradiated RTtZDT by at least 120OF for normal operation when the pressure exceeds 20 percent of the pre-service hydrostatic test pressure (3106 psig), which is 621 psig 4 1 for the D.C. Cook Unit 2 reactor vessel.

The limiting unirradiated RTnDT of 30'F occurs in the vessel flange of the D.C. Cook Unit 2 reactor vessel, so the minimum allowable temperature of this region is 150°F at pressure greater than 621 psig without uncertainties. This limit is reflected in the heatup and cooldown curves shown in Figures 9-1 through 94.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

4-1 4.0 CHEMISTRY FACTOR DETER-MINATION 4.1 Chemistry Factor Methodology:

The calculations of chemistry, factor (CF) values for the D.C. Cook Unit 2 reactor vessel beltline materials are performed in accordance with Regulatory Guide 1.99, Revision 2 as follows:

The CF is based on the Cu and Ni weight % of the material or it is based on the results of surveillance capsule test data. When the weight percent of copper and nickel is used to determine the CF. the CF is obtained from either Table 1 or Table 2 of Regulatory Guide 1.99, Revision 2. The results of this method are given in Table 1-4.

When surveillance capsule data is used to determine the CF, the CF is determined as follows:

CF Ell [,a x iO.28-O.11ogfi)]"

CF =2=,,x.t 9

E,,[ f ( o.,28-o.11ogf ) I zF9 Where:

n

=

The Number of Surveillance Data Points A,

=

The Measured Value of ARTN-DT f,

=

Fluence for each Surveillance Data Point When the surveillance weld copper and nickel content differs from that of the vessel weld, the measured values of ARTNUT are adjusted by multiplying them by the ratio of the chemistry factor for the vessel weld to that for the surveillance weld based on the copper and nickel content of the materials.

The Ratio Procedure is documented in Regulatory Guide 1.99 Revision 2 Position 2. 1. and shown below.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

4-2 4.1 1 Application of the Ratio Procedure:

The D.C Cook Unit 2 intermediate and lower shell axial weld seams, the intermediate to lower shell girth weld seam, and the surveillance program weld metal were all fabricated with weld wire type ADCONI INMM, Heat Number $3986 and Flux Type Linde 124, Lot Number 934. Despite the fact that all the welds are made of the same heat and flux, the weight percent copper and nickel of the surveillance weld metal differs slightly versus the overall best estimate chemistry for the vessel weld metal (Per D.C. Cook Design Information Transmittal, DIT-B-022301111).

As reported in Table 4-1. the chemistry factor of the surveillance weld is 75.0°F, while the vessel weld chemistry factor is 76.40F. This produces a ratio of

1. 019. Therefore, a ratio of 1.0 19 was applied to the measure weld metal ART,'CT values.

4.1.2 Temperature Effects on Surveillance Data:

Studies have shown that for temperatures near 5500F, a I°F decrease in irradiation temperature will result in approximately I°F increase in ARTN-DT. Thus, for plants that use surveillance data from other reactor vessels that operate at a different temperature or when the capsule is at a different temperature than the plant, then this difference must be considered.

The temperature adjustment is as follows:

Temp. Adjusted ARTN-.c = ARTNiT Measured - (TLapsuie - Tplant)

The D.C Cook Unit 2 capsules are located in the reactor between the thermal shield and the vessel wall and are positioned opposite the center of the core. The test capsules are in guide tubes attached to the thermal shield. The location of the specimens with respect to the reactor vessel beltline provides assurance that the reactor vessel wall and the specimens experience equivalent operating conditions and the temperatures will not differ by more than 250F. Hence, no temperature adjustment was made.

Following in Table 4-1 are best estimate chemistry values for all the beltline materials, including the surveillance capsule weld along with the chemistry factors (CF) as determined per Regulatorn Guide 1.99, Revision 2, Position I or 2 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

4-3 NOTES:

(a) These values were determined bv ATI and Transmitted to Westinghouse via DIT-B-02230-00'".

(b) Actual value was 0. 125 and was conservatively rounded to 0.130. It should also be noted that Inter. Shell Plate 10-2 has credible surveillance data, overriding the weight percent Cu & Ni.

Table 4-2 provides the calculation of the CF values for the surveillance materials per Regulatory Guide 1.99, Revision 2. Position 2.1. The ratio procedure of Regulatory Guide 1.99, Revision 2, Position -. I will be applied to the weld metal (ie. Ratio = Vessel CF + Surv. CF = 76.4 + 75. 0 = 1.019).

D.C. Cook Unit 2 Hearup and Cooldown Limit Curves TABLE 4-1 Reactor Vessel Beltline Material Copper and Nickel Content and Calculated CF Material Description wt. % Cu a) wt. % N1(3)

CF Inter. Shell Axial Welds 0.056

0. 956 76.4 0F Inter. Shell Plate 10-1 0.150 0.570 108.4,F (C5556-2)

Inter. Shell Plate 10-2

0. 130 b 0.580 90.40F (C5521-2)

Int/Lower Shell Circ Weld 0 056 0.956 76.40F Lower Shell Axial Welds 0.056 0.956 76.4°F Lower Shell Plate 9-1 0.110 0.640 74.60F (C5-540-2)

Lower Shell Plate 9-2 0.140 0.590 99-50F (C5592-1)

Surveillance Weld Metal 0.055 0.97 750F

4-4 (a) Calculated Fluence values are in units of n/cm., E > 1.0 MeV.

(b) Data obtained from WCAP-13515 Rev. I, revised Capsule U Analysis.

(c) Increased by a ratio of 1. 019 to account for difference between the vessel weld chemistry and the surveillance weld chemistry (76.4/75.0). The original ARTNT values are in parenthesis.

D.C. Cook Umt 2 Heatup and Cooldown Limit Curves

4-5 4 2 Surveillance Program Credibility Evaluation:

Regulatory Guide 1.99, Revision 2, describes general procedures acceptable to the NRC staff for calculating the effects of neutron radiation embrittlement of the low-alloy steels currently used for light water-cooled reactor vessels.

Position C 2 of Regulatory Guide 1.99, Revision 2, describes the methodology for calculating the adjusted reference temperature and Charpy upper-shelf energy' of reactor vessel beltline materials using surveillance capsule data. The methods of Position C.2 can only be applied when two or more credible surveillance data sets become available from the reactor in question.

To date, there have been four surveillance capsules removed from the D.C. Cook Unit 2 reactor vessel.

This capsule data must be shown to be credible-In accordance with the discussion of Regulatory Guide 1.99, Revision 2, there are five requirements that must be met for the surveillance data to be judged credible.

The purpose of this evaluation is to apply the credibility requirements of Regulatory Guide 1.99, Revision 2, to the D.C. Cook Unit 2 reactor vessel surveillance data and determine if the Cook Unit 2 surveillance data is credible.

Criterion 1:

Materials in the capsules should be those judged most likely to be controlling with regard to radiation embrittlement.

The beltline region of the reactor vessel is defined in Appendix G to 10 CFR Part 50, "Fracture Toughness Requirements", December 19, 1995 to be:

"the reactor vessel (shell material including welds, heat affected zones, and plates or forgings) that directly surrounds the effective height of the active core and adjacent regions of the reactor vessel that are predicted to experience sufficient neutron radiation damage to be considered in the selection of the most limiting material with regard to radiation damage."

DC. Cook Unit 2 Heatup and Cooldown Limit Curves

4-6 Hence, the D.C. Cook Unit 2 reactor vessel consists of the following beltline region materials:

a)

Intermediate Shell Plate C5556-2, b) Intermediate Shell Plate C5521-2, c) Lower Shell Plate C5540-2, d)

Lower Shell Plate C5592-1, and e) Intermediate and lower shell axial weld seams and the intermediate to lower shell girth weld seams were fabricated with weld wire type ADCOM INMM, Heat # S3986 and Flux Type Linde 124, Lot 934. The surveillance weld was fabricated for the same weld wire and flux. (See Reference 2)

Per WCAP-8512, the D.C. Cook Unit 2 surveillance program was based on ASTM E185-73, -Standard Recommended Practice for Surveillance Tests for Nuclear Reactor Vessels" Per Section 4 of ASTM E 185-73, "The test materials should be selected on the basis of initial transition temperature, upper shelf energy level, and estimated increase in transition temperature considering chemical composition (copper(Cu) and phosphorus(P)) and neutron fluence.

Recommended procedures for selection of materials are presented in Annex A]" (ie. Annex Al of ASTM E185-73). Following is the evaluation of the selection of the D.C. Cook Unit 2 surveillance materials.

Weld Metal:

All vessel beltline welds were fabricated with weld wire typ e ADCOM INMM, Heat 4 S3986 and Flux Type Linde 124, Lot 4 934. The surveillance weld was fabricated from the same weld wire heat and flux.

Hence, the surveillance weld metal is the same as all beltline welds and therefore, is representative of all beltline weld seams.

DC. Cook Unit 2 Heatup and Cooldown LIMirt Curves

4-7 Platesý Per Paragraph AI 1.1 of Annex to ASTM E185-73, "Base metals exhibiting differences in intial RT

-*T temperatures of 30°F (-1. 1OC) or less shall be considered equivalent."

The lower shell plates have an initial RTiizT temperature of -200F. These initial RTN-DT temperatures are well below the initial RTNDT temperatures of the intermediate shell plates, therefore, intermediate shell plates are considered more limiting than the lower shell plates.

Intermediate shell plate C5556-2 has an initial RTNDT temperature of 58°F and the intermediate shell plate C5521-2 has an initial RTN-DT temperature of 380F. Hence, based on the above criteria these two initial RTNLDT temperatures are considered equivalent.

Per Paragraph Al.1. 1 of Annex to ASTM E185-73, "... base metals (or weld metals) having differences in copper content of 0.03 weight % or less and differences in phosphorus content of 0.003 weight % or less shall be considered equivalent.

The difference in copper content of intermediate shell plate C5556-2 and C5521-2 is 0.01% and the difference in phosphorus content of intermediates shell plate C5556-2 and C5521-2 is 0.001°%.

Hence based on the above criteria these two plates are considered equivalent.

Per Figure Al of the Annex to ASTM E185-73, when the initial RTN-DT temperatures, copper content and phosphorus content are all equivalent, the base material with the lowest initial upper shelf energy (USE) should be selected. The initial USE of intermediate shell plate C5556-2 is 90 ft-lb and the initial USE of intermediate shell plate C5521-2 is 86 ft-lb. Hence, based on the preceding evaluation and the available methodology at the time that the D.C. Cook Unit 2 surveillance program was developed intermediate shell plate C5521-2 was the limiting beltline plate material.

Therefore, the materials selected for use in the D.C. Cook Unit 2 surveillance program were those judged to be most likely controlling with regard to radiation embrittlement according to the accepted methodology at the time the surveillance program was developed. Based on engineering judgment the D.C. Cook Umt 2 surveillance program meets the intent of this criteria.

D C. Cook Unit 2 Heatup and Cooldown Limit Curves

4-8 Criterion 2:

Scatter in the plots of Charpy energy versus temperature for the irradiated and unirradiated conditions should be small enough to permit the determination of the 30 ft-lb temperature and upper shelf energy, unambiguously.

Plots of Charpy energy versus temperature for the unirradiated and irradiated conditions are presented in References 4, 6, 7 and 8. Based on engineering judgment, the scatter in the data presented in those reports is small enough to determine the 30 ft-lb temperature and upper shelf energy of the D.C. Cook Unit 2 surveillance materials unambiguously. Therefore, the D.C. Cook Unit 2 surveillance program meets this criteria.

Criterion 3:

When there are two or more sets of surveillance data from one reactor, the scatter of ART,,, values about a best-fit line drawn as described in Regulatory Position 2.1 normally should be less than 28' Ffor welds and 17' Ffor base metal. Even if the fluence range is large (two or more orders of magnitude), the scatter should not exceed twice those values. Even if the data fail this criterion for use in shift calculations, they may be credible for determining decrease in upper shelf energy if the upper shelf can be clearly determined, following the definition given in ASTM El85-82.

The least squares method, as described mI Regulatory' Position 2. 1, will be utilized in determining a best-fit line for this data to determine if this criteria is met.

D C. Cook Unit 2 Heatup and Cooldown Limit Curves

4-9 TABLE 4-3 Calculation of Chemistry Factors using D.C. Cook Unit 2 Surveillance Capsule Data Material Capsule Fluence.'b)

FF

_ARTNOT~

FF * \\,RTNDT FF2 Intermediate T

2 38 x 10W 0.612 55 33.66 0.375 Shell C5521-2 Y

6.64 x 108 0.885 90 79.65 0.783 (longitudinal)

X 1.019 x 10ý1 1.005 95 95.48 1.010 U

1-583 x 10" 1.127 95 107.07 1.270 Intermediate T

2.38 x 10"8 0.612 80 48.96 0.375 Shell C5521-2 Y

6.64 x 1018 0.885 100 88.50 0.783 (Transverse)

X 1.019 x loll 1.005 103 103.52 1.010 U

1.583 x 10i 9 1.127 130 146.51 1.270 SUM:

703.35 6.876 CF = Y(FF RTNET) +

FF2 ) (703.35) + (6.876) = 102.3°F T

238 x10"8 0.612 40 24.48 0.375 Weld Metal y

6.64 x 10" 0.885 50 44.25 0.783 X

1.019 x lol9 1.005 70 70.35 1.010 U

1.583 x 10" 1.127 75 84.53 1.270 SUM:

223.61 3.438 CF = E(FF

• RTNDr)

( F(FF)

= (223.61) + (3.438) = 65.0°F (a) Calculated Fluence values are in units of n/cm 2, E > 1.0 MeV (b) Data obtained from WCAP-135 15 Rev. 1 [l revised Capsule U Analysis.

D.C. Cook Unit 2 Hearup and Cooldown Limit Curves

4-10 Plate Material-STABLE 4-4 D.C. Cook Unit 2 Surveillance Capsule Data Scatter about the Best-Fit Line for the Intermediate Shell Plate C5521-2 Material Intermediate Shell Plate FF Measured Best Fit Scatter of C5521-2 Orientation ARTNDT ART.DT ART-iT (OF)

(30 ft-lb) (-F)

(OF)

Longitudinal 0.612 55 62.6 7.6 (CF = 102.3 0F) 0.885 90 90.5 0.5 1.005 95 102.8 7.8 1.127 95 115.3 20.3 Transverse 0.612 80 62.6

-17.4 (CF = 102.3°F) 0.885 100 90.5

-9.5 1.005 103 102.8

-0.2 1.127 130 115.3

-147 Table 4-4 indicates that one measured plate ARTN'nr value is above the upper bound 1 of 178F by less than 18F. Meaning the best-fit line is slightly under predicting this measured ARTN-*T value-Table 4-4 also indicates that one measured plate ART>[r value is below the lower bound 1a of 17SF by approximately 38F. From a statistical point of view, -la (178F) would be expected to encompass 68% of the data. Therefore, it is still statistically acceptable to have two of the plate data points fall outside the

+/-+I bounds. The fact that two of the measured plate.xRTN-rT values are outside of 1 bound of 17SF can be attributed to several factors, such as i) the inherent uncertaintv in Charpy test data, 2) the use of hand fit Charpy curves, using engineering judgment, for the ARTNDT versus an asmnimetric or symmetric tangent Charpy curve fitting program and/or 3) rounding errors.

D.C. Cook Unit 2 Heatup and Cooldowi Limit Curves

4-11 Weld Metal:

TABLE 4-5 D.C. Cook Unit 2 Surveillance Capsule Data Scatter about the Best-Fit Line for the Weld Material FF Measured Best Fit`ý Scatter of ARTNDT (OF)

ARTm-T ARTNDTT (30 ft-lb) (IF)

(OF) 0.612 40 39.8

-0.2 0.885 50 57.5 7.5 1.005 70 65.3

-4.7 1.127 75 73.3

-1.7 NOTES:

(a) The Chemistry Factor used for the best fit ARTNDT is 65.0 0F.

The scatter of ARTN'T values about a best-fic line drawn, as described in Regulatory Position 2.1, is less than 280F as shown above. Therefore, this criteria is met for the D.C. Cook Unit 2 surveillance weld material. Since surveillance Weld data is credible, a aA margin of 14°F will be used when predicting the Cook Unit 2 beltline weld material properties.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves 4-II

4-12 Criterion 4:

The irradiation temperature of the Charpy specimens in the capsule should match the vessel wall temperature at the cladding/base metal interface within +/- 25 oF.

The D.C-Cook Unit 2 capsule specimens are located in the reactor between the thermal shield and the vessel wall and are positioned opposite the center of the core. The test capsules are in the guide tubes attached to the thermal shield. The location of the specimens with respect to the reactor vessel beltline provides assurance that the reactor vessel wall and the specimens experience equivalent operating conditions and the temperatures will not differ by more than 250F. This engineering judgment is accepted by the NRC.

Criterion 5:

The surveillance data for the correlation monitor material in the capsule should fall within the scatter band of the data base for that material The D.C. Cook Unit 2 surveillance program does not include correlation monitor material. Therefore, this criteria is not applicable to D.C. Cook Unit 2.

Based on the preceding responses to the criteria of Regulatory Guide 1.99, Revision 2, Section B, and the application of engineering judgment, the D.C. Cook Unit 2 surveillance data is credible.

4.2.1 Application of the Credibility Criteria:

The D.C. Cook Unit 2 surveillance data is deemed credible per Regulatory Guide 1.99, Revision 2. Hence,

]

will be used in the ART evaluations for the surveillance program materials.

4 2.2 cya and How it was Determined Per Regulatory Guide 1,99, Revision, 2 Position 1. 1, the values of CA are referred to as '"280F for welds and 170F for base metal, except that c7, need not exceed 0.50 times the mean value of ARTrDrT" The "mean value of ARTNCT" is defined in Regulatory Guide 1.99, Revision 2, by Equation 2. The chemistry factor in Regulatory Guide 1.99. Revision 2. Equation 2 is calculated from Tables I and 2 or Position 2 1 of Regulatory Guide.99, Revision 2.

Per Regulatory Guide 1.99, Revision, 2 Position 2. 1, when there is credible surveillance data, CA is taken to be the lesser of V Ž_RTýrD-, or 140F (28°F/2) for welds, or 8.5°F (170F/2) for base metal.

R*RRT-again is defined herein by Equation 13, while utilizing a "Best-Fit Chermstry Factor" calculated in accordance with Position 2I1 of Regulatory Guide 1.99, Revision 2 and is shown herein on Table 4-1.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

5-1 5.0 UNIRRADL-\\TED PROPERTIES 5.1 Initial RT9rT of Beltline Materials Charpy V-notch impact specimens from the base material plates of the reactor vessel were machined in the longitudinal orientation (longitudinal axis of the specimen parallel to the major working direction of the plate) and the transverse orientation (longitudinal axis of the specimen perpendicular to the major working direction of the plate). The core region weld Charpy impact specimen was perpendicular to the weld direction. The notch of the weld metal Charpy specimen was machined such that the direction of crack propagation in the specimen was in the welding direction.

Table 5-1 contains a description of the beltline materials and their initial RTN-rD values.

NOTESý (a) The Initial RTNT values were obtained from WCAP-13515 [4 and are measured values.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves TABLE 5-1 Reactor Vessel Material Initial RTnT Material Description Heat #

Flux Type Flux Lot Initial RT\\1T"'

D.C-Cook Unit 2 Inter. Shell Axial Welds S3986 Linde 124 0934

-350F Inter. Shell Plate 10-1 C5556-2 58°F Inter. Shell Plate 10-2 C5521-2 38F InutLower Shell Circ. Weld S3986 Linde 124 0934

-35°1 Lower Shell Axial Welds S3986 Linde 124 0934 F Lower Shell Plate 9-1 C5540-2 20°F Lower Shell Plate 9-2 C5592-1 20°F Surveillance Weld S3986 Linde 124 0934 Closure Head Flange 20°F (4437-V-1)

Vessel Flange (4436-V-2) 30°F

5.2 Determination of cai Since the initial RT,,jw values are measured values, the D.C. Cook Unit 2 Om values are 0F.

5-3 Bolt-up Temperature:

The minimum bolt-up temperature requirements for the D.C. Cook Unit 2 reactor pressure vessels are according to Paragraph G-2222 of the ASME Boiler and Pressure Vessel (B&P'VD Code,Section XI, Appendix G,. the reactor vessel may be bolted up and pressurized to 20 percent of the initial hydrostatic test pressure at the initial RTN1DT of the material stressed by the bolt-up.

Therefore, since the most limiting initial RT,,,-u value is 300F (vessel flange), the reactor vessel can be bolted up at 300F. However, based on engineering judgment Westinghouse recommends a bolt-up of at least 600F.

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

6-1 6.0 REACTOR VESSEL GEOMETRIC & SYSTEM PARA.METERS 6.1 Reactor Vessel Physical Dimensions and Operating Conditions:

The following are the D.C. Cook Unit 2 reactor vessel physical dimensions and operating conditions:

Reactor vessel inner diameter (to clad)

= 173 inches Clad thickness

= 7/32 inches Reactor Vessel Beltline Thickness

= 8.5 inches Pre-Service System Hydrostatic Pressure

= 3106 psig Capacity Factor (Future Cycles)

= 90%

System and Component Operating Conditions/Dimensions:

Design Pressure

= 2485 psig Operating Pressure

= 2235 psig D C Cook Umt 2 Heatup and Cooldown Limit Curves

7-1 7 0 FLUENCE FACTOR DETERMINATION 7.1 Peak Clad Base Metal Interface Fluence for each Belthne Material:

Contained in Table 7-1 are the reactor vessel clad/base metal interface fluences.

These values were obtained from WCAP-13515 Revision I*

"Analysis of Capsule U from the Indiana Michigan Power Company D.C. Cook Unit 2 Reactor Vessel Radiation Surveillance Program".

TABLE 7-I Calculated Fluence (10'9 n/cm, E > 1.0 MeV) at the Pressure Vessel Clad/Base Metal Interface for the D C. Cook Unit 2 Reactor Vessel EFPY 00 150 300 45° 0 626 0 435 0.357 12.20 (EOC 11) 13.60 (EOC 12) 0.248 0.384 0.469 32 0.527 0.837 1.128 48 0.771 1.232 1.706 Per AEP the current end of license (EOL) EFPY is 32 EFPY and the EOL license renewal EFPY is 48 EFPY.

Thus, the EFPY values used to generate pressure/temperature curves and the calculated fluence values are:

Current EOL = 32 EFPY Renewal EOL = 48 EFPY Cook Unit 2 has longitudinal weld seams at 00 and 100 azimuthal angles. However. all beltline welds were fabncated with the same weld wire and flux, thus the girth weld will receive the peak vessel fluence. Since the girth weld seam will receive a higher fluence than the longitudinal weld seams, only the peak vessel fluence will be used for the ART calculations (ie. The girth weld will bound all other belthlne weld seams).

In addition, all beltline plates will receive the peak vessel fluence D.C. Cook Unit 2 Heatup and Cooldown Limit Curves 0.231

7-2 7.2 1/4T & 3/4T Thickness Fluence for each Beltline Material.

The neutron fluence at the lI4T & 3/4T depth in the vessel wall was calculated per Regulatory Guide 1 99, Revision 2, as follows:

f = f"-* e-

, 10 r n/cm" (E > 1.0 MeV)

(10) where.

f,.z- = Vessel inner wall surface fluence, 10'9 n/cm2 (E > 1.0 MeV) (See Table 7-1) x

= is the depth into the vessel wall from the inner surface, inches (0.25

• 8.5 inches or 0.75

• 8.5 inches)

Contained in Table 7-2 is a summary of the fluence values used to calculate the D.C. Cook Unit 2 ART values used to develop the pressure-temperature curves for normal operation.

7.3 Fluence Factors:

The fluence factors were calculated per Regulatory Guide 1.99, Revision 2. using the following equation.

FF = fluence factor = f

-1logf?)

(11) where:

f = Vessel inner wall surface fluence. 1/4 T fluence or 3/4T fluence,

[10 9 n/cm' (E > 1.0 MeV) + 1019 n/cmn (E > 1.0 MeV)]

Contained in Table 7-3 is a summary of the calculated fluence factors for 32 and 48 EFPY.

D.C Cook Unit 2 Heatup and Cooldo-n Limit Curves TABLE 7-2 Summary,' of Fluence Values Used to Calculate the D.C. Cook Unit 2 ART Values EFPY Peak CladlBase l/4T Fluence 314T Fluence Metal Fluence (E > 1.0 MeV)

(E > 1.0 MeV)

(E > 1.0 MeV) 32 1.625 x 1019 ni/cm2 9.75 x 10" rnicm 2 3.51 x 101 n/cm:

48 2.457 x 1019 n/cmr 1.475 x l09 nrcm 5.32 1?x 10 n/cm'

7-3 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

6' 8-1 8.0 CALCULATION OF ADJUSTED REFERENCE TEMPERATURE

8.1 Methodology

From Regulatory Guide 1.99, Revision 2. the adjusted reference temperature (ART) for each material in the beltline region is given by the following expression:

ART = Initial RT.VDT -

-A RT,,nD - Margin (12)

Initial RTNDT is the reference temperature for the unirradiated material as defined in paragraph NB-233 1 of Section III of the AS)ME Boiler and Pressure Vessel Code' 91. If measured values of initial RTN-ir for the material in question are not available, generic mean values for that class of matenial may be used if there are sufficient test results to establish a mean and standard deviation for the class.

ART*m-r is the mean value of the adjustment in reference temperature caused by irradiation and should be calculated as follows:

A RTVDT = CF *f(o.

2 -ao-Ologf (13)

To calculate ARTNDT at any depth (e.g., at 1/4T or 3/4T), the following formula must first be used to attenuate the fluence at the specific depth. The resultant fluence is then placed in the equation above to calculate the ARTNDT at the specific depth. The calculated CF and FF values are given in Tables 4-1, 4-2 and 7-3 of this report.

f(depth x) =

fsiac

• ce (0

4 x)

(14)

When there are -two or more credible surveillance data sets"M available, Regulatory Guide 1.99 Revision 2, Position 2.1. states "To calculate the Margin in this case, use Equation 4; the values given there for g_ý may be cut in half'. Equation 4 from Regulatory Guide 1.99 Revision 2, is as follows:

V.VI

=

oU-o (15)

The values of ca are referred to as -23°F for welds and 170F for base metals."

Standard Deviation for Initial RT\\DT Margzin Term., ;-: If the initial RT',,.T values are measured values.

then am is taken to be 0°F, otherwise use 170F.

Standard Deviation for ARTN-,TT Margin Term, c7,: Per Regulatorv Guide 1.99 Revision 2. Position 1 I. the values of c7,_ are referred to as -.28oF for welds and 17°F for base metal, except that c;,_ need not exceed 0.50 times the mean value of ARTCT."

The "mean value of ARTT4n" is defined in Regulatory Guide 1.99 D C. Cook Unit 2 Heatup and Cooldown Limit Curves

8-2 Revision 2. by Equation 2. The chemistry factor in Regulatory Guide 1 99, Revision 2. Equation 2 is calculated from Tables I and 2 of Regulatory Guide 1.99 Revision 2 Per Regulatory Guide 1.99, Revision 2, Position 2.1, when there is credible surveillance data, a, is taken to be the lesser of VZLARTNDT or 14°F (280 F/2) for welds, or 8.50F (17°F/2) for base metal.

,RTtCT again is defined herein by Equation 4, while utilizing a "Best-Fit Chemistry Factor" calculated in accordance with Position 2.1 of Regulatory Guide 1.99, Revision 2.

Since ai is taken to be zero when a heat-specific measured value of initial RTN-DT are available (as they are in this case), the total margin term, based on Equation 4 of Regulatory Guide 1.99. Revision 2, is as follows:

Position 1.1 Lesser of ARTNUT or 56°F for Welds Lesser of ARTN-DT or 340F for Base Metal Position 2.1:

Lesser of ART.-T or 28°F for Welds Lesser of ARTNDT or 170F for Base Metal 8.2 Adjusted Reference Temperature (ART) Calculations:

The ART calculations along with the actual margin terms used for D.C. Cook Unit 2 are listed in Tables 8-1 through 8-4.

D C Cook Unmt 2 Heatup and Cooldown Limit Curves

8-3 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves TABLE 8-1 Calculation of the ART Values for D.C. Cook Unit 2 for the 1/4T Location and 32 EFPY Material RG 1.99 CF FF ARTN-DT Margin IRTh-T ART R2 Method Intermediate Shell Plate Position 1.1 108.4 0F

.993 107 60F 340F 58°F 200 C5556-2 I

Position 1. 1 90.4 0F

.993 89.8 0F 340F 38°F 162 Intermediate Shell Plate C5521-2 Position 2.1 102.3 0F

.993 l01.6°F 170F 38°F 157 Lower Shell Plate Position 1,1 74.60F

.993

74. 1OF 34°F

-20OF 88 C5540-2 Lower shell Plate Position 1.1 99.5°F

.993 98.80F 340F

-20OF 113 C5592-1 Beltline Weld Seams Position 1. 1 76.4 0F

.993 75.9 0F 560F

-35°F 97 (Circ. Weld is Limiting)

Position 2.1 66.30F

.993 65.8 0F 28°F

-35°F 59

8-4 8-4 D C. Cook Unit 2 Heatup and Cooidowvn Limit Curves TABLE 8-2 Calculation of the ART Values for D C. Cook Unit 2 for the 3/4T Location and 32 EFPY Material RG 1.99 CF FF ARTN-DT Margin IRTT ART R2 Method Intermediate Shell Plate Position 1. 1 108.4 0F

.711

77. 1°F 34°F 58°F 169oF C5556-2 Intermediate Shell Plate Position 1. 1 90.4°F

.711 64.30F 340F 38°F 136°F C5521-2 Position 2.1 102.3 0F

.711 72.7 0F 17-F 38°F 128°F Low er Shell Plate I-0 F6 o

Lower Position 1.1 74.60F

.711 53.0°F 340F

-200F 67°F C554o-2 Lower shell Plate Position 1. I 99.5OF

.711 70.7°F 34°F

-20°F 850F C5592-1 I

Beltline Weld Seams Position 1.1 76.4 0F

.711 54.3 0F 54.3 0F

-35°F 740F (Circ. Weld is Limiting)

Position 21 1 66.3 0F

.711

47. 1OF 28OF

-35 FF 40OF

8-5 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves TABLE 8-3 Calculation of the ART Values for D.C. Cook Unit 2 for the 1/4T Location and 48 EFPY Material RG 1.99 CF FF ART,,[-,T Margin IRT,,,DT ART R2 Method Intermediate Shell Plate Position 1.1 108.4 0F 1.108 120.1OF 340F 58OF 212 0F C5556-2 Intermediate Shell Plate Position 1. 1 90.4°F 1.108 100.2 0F 340F 38oF 172cF C5521-2 Position 2.1 102.30F 1.108 113.3OF 170F 38OF 168°F Lower Shell Plate C5540-2 Position 1. 1 74.60F 1.108 82.7 0F 340F

-20oF 97oF Lower shell Plate C5592-1 Position 1.1 99.50F 1.108 110.2 0F 340F

-20oF 124 0F Beftline Weld Seams Position 1.1 76.4 0F 1.108 84.7 0F 560F

-35oF 106oF (Circ. Weld is Limiting)

Position 2.1 66.3 0F 1.108 73.5 0F 28oF

-350F 67 0F

8-6 D.C. Cook Unit 2 Heatup and Cooldown Limut Curves TABLE 8-4 Calculation of the ART Values for D.C, Cook Unit 2 for the 3/4T Location and 48 EFPY Matenal RG 1.99 CF FF ARTNDT Margin IRTMDT ART R2 Method Intermediate Shell Plate Position 1.1 108.4 0F

.824 89.3cF 340F 58°F 181-F C5556-2 Intermediate Shell Plate Position 1.1 90.40F

.824

74. 5F 340F 380F 146°F C5521-2 Position 2.1 102.30F

.824 84.30F 175F 38OF 139°F Lower Shell Plate Position 1.1 74.6 0F

.824 61.5 0F 34°F

-20°F 750F C5540-2 Lower shell Plate Position I1A 99J5°F

.824 82.0°F 340F

-20OF 960F C5592-1 Beltline Weld Seams Position 1.1 76.4 0F

.824 63.0°F 56:F

-35°F 840F (Circ. Weld is Limiting)

Position 2.1 66.3°F

.824 54.6 0F 28°F

-350F 48°F

8-7 Contained in Table 8-5 is a summary of the limiting ART values used in the generation of the D C. Cook Unit 2 reactor vessel heatup and cooldown curves.

• Intermediate shell plate 10-1 (Heat 9 C5556-2) is the limiting material for all cases.

DC. Cook ULit 2 Hearup and Cooldown Limit Curves TABLE 8-5 Summary of the Lirmting ART Values* to be Used in the Generation of the Cook Unit 2 Reactor Vessel Heatup and Cooldown Curves EFPY 1/4 T Limiting ART 3/4 Limiting ART 32 200°F 169 0F 48 212OF 1810F

9-1 9.0 HEATUP AND COOLDOWN PRESSURE-TEMPERATURE LIMIT CURVES 9.1 Introduction and Methodology:

Pressure-temperature limit curves for normal heatup and cooldown of the primary reactor coolant system have been calculated for the pressure and temperature in the reactor vessel beltline region using the methods discussed in Sections 3 and 8 of this report.

Figure 9-1 presents the heatup curves without margins for possible instrumentation errors for a heatup rate of 60°F/hr.

This curve is applicable to 32 EFPY (current end of license).

Figure 9-2 presents the cooldown curves without margins for possible instrumentation errors for cooldown rates of 0, 20, 40, 60, and 100 0F,*hr. These curves are also applicable to 32 EFPY (current end of license). Figure 9-3 presents the heatup curves without margins for possible instrumentation uncertainty for a heatup rates of 600F/hr.

This curve is applicable to 48 EFPY (end of license renewal). Figure 9-4 presents the cooldown curves without margins for possible instrumentation uncertainty for cooldown rates of 0, 20, 40, 60. and 1000F/hr.

These curves are also applicable to 48 EFPY (end of license renewal).

Allowable combinations of temperature and pressure for specific temperature change rates are below and to the right of the limit lines shown in Figures 9-1 through 9-4. This is in addition to other criteria, which must be met before the reactor is made critical, as discussed in the following paragraphs.

The reactor must not be made critical until pressure-temperature combinations are to the right of the criticality limit line shown in Figures 9-1 and 9-3. The straight-line portion of the criticality limit is at the minimum permissible temperature for the 2485 psig inservice hydrostatic test as required by Appendix G to 10 CFR Part 50. The governing equation for the hydrostatic test is defined in Code Case N-640"21 and Appendix G to Section XI of the ASME Code[31 as follows:

.5 K*,,, < Ki (15)

where, KL, is the stress intensity factor covered by membrane (pressure) stress, Ki;= 33.2 - 20_734 exp [0.02 (T - RTNDT)],

T is the minimum permissible metal temperature, and RTM,,ZT is the metal reference nil-ductility temperature D.C. Cook Unit 2 Hearup and Cooldown Limit Carves

The criticality limit curve specifies pressure-temperature limits for core operation to provide additional margin during actual power production as specified in Reference 2. The pressure-temperature li mts for core operation (except for low power physics tests) are that the reactor vessel must be at a temperature equal to or higher than the minimum temperature required for the mserv ice hydrostatic test, and at least 40°F higher than the minimum permissible temperature in the corresponding pressure-temperature curve for heatup and cooldown calculated as described in Section 3 of this report. For the heatup and cooldown curves without margins for instrumentation errors, the minimum temperature for the in service hydrostatic leak tests for D.C. Cook Unit 2 reactor vessel at 32 and 48 EFPY is 260°F and 2720F, respectively. The vertical line drawn from these points on the pressure-temperature curve, intersecting a curve 40°F higher than the pressure-temperature hmit curve, constitutes the limit for core operation for the reactor vessel.

Figures 9-1 through 9-4 define all of the above limits for ensuring prevention of nonductile failure for the D.C. Cook Unit 2 reactor vessel. The data points for the heatup and cooldown pressure-temperature limit curves shown in Figures 9-1 through 9-4 are presented in Tables 9-1 through 9-4.

D C. Cook Unit 2 Heatup and Cooldown Limit Curves

9-3 NMATERILkL PROPERTY BASIS LIMITING NLMATERLA.:

Intermedi.

LIMITING ART VA-LUES AT 32 EFPY:

2500 Operlim,ersmor 5 17 jn 27021 1 Leak Test Limit 2250 Unacceptable 2000 Operation 1750 t a

(n Cn a

ia)

(UI CU 1500 1250 1000 750 500 250 0

ate Shell Plate C5556-2 I/4T, 200OF 3/4T, 169oF 0

50 100 150 200 250 300 350 400 450 500 550 Moderator Temperature (Deg. F)

FIGURE 9-1 D.C. Cook Umt 2 Reactor Coolant System Heatup Limitations (Hearup Rate of 600Flir) Applicable for 32 EFPY (Without Margins for Instrumentation Errors)

(Includes Vessel Flange Requirements of I500F and 621 psi per I0CFR0)

D C. Cook Unit 2 Heatup and Cootdown Lirrut Curves

9-9-4 NL-\\TERAL-L PROPERTY BASIS LIMITING MATERIAL:

Intermediate Shell Plate C5556-2 LIMITING ART VALUES AT 32 EFPY.

1/4T, 200cF 3/4T, 169cF 2500 2250 2 Unacceptable 2000 Operation 1750 1500 1250 1000 750 500 250 0

O peration Cooldown Rates F/H r steady-sta te

-20

-40

-60

-100 Boltu p 0

50 100 150 200 250 300 350 400 450 500 550 Moderator Temperature (Deg. F)

FIGURE Q-2 D.C. Cook UrUt 2 Reactor Coolant System Cooldown Limitations (Cooldown Rates of 0, 20, 40, 60 and l00°F/hr) Applicable for 32 EFPY (Without Nlargins for Instrumentation Errors) (Includes Vessel Flange Requirements of 150°F and 621 psi per 10CFR50)

D.C. Cook Umt 2 Heatup and Cooldown Limit Curves 0~

0~

0

9-5 NMkTERIAL PROPERTY BASIS LIMITING MATERIAL LIMITING ART VALdUES AT 48 EFPY:

2500 2250 2000 1750

3.

E 1500 1250 1000 750 500 250 0

Intermediate Shell Plate C5556-2 1/4T. 212°F 3/4T, 18IF 0

50 100 150 200 250 300 350 400 450 500 Moderator Temperature (Deg. F) 550 FIGURE 9-3 D.C. Cook Unit 2 Reactor Coolant System Heatup Limitations (Heatup Rate of 60°F'hr) Applicable for 48 EFPY (Without Margins for Instrumentation Errors)

(Includes Vessel Flange Requirements of 150 0F and 621 psi per 10CFRS0)

D C. Cook Unit 2 Heatup and Cooldown Limit Curves

NMATERIAL PROPERTY BASIS LIMITING MATERIAL:

Intermediate Shell Plate C5556-2 LIMITING ART VALUES AT 48 EFPY:

l/4T, 212°F 3/4T, 18IF 2500 perm version 5 1 Run

-5335

]

2250 I

2Unacceptable 2000 t Operation 1750 CL 1500 in V

W 1250 "a,

CL

= 1000 750 500 250 0

Acceptable Operation Cool do-n Rates F/H r stead y-sta te

-20

-40

-60

-100 0

50 100 150 200 250 300 350 Moderator Temperature (Deg.

FIGURE 9-4 400 450 500 550 F)

D.C Cook UnIt 2 Reactor Coolant System Cooldown Limitations (Cooldown Rates of 0.

20, 40. 60 and 100°F"hr) Applicable for 48 EFPY (Without Margins for Instrumentation Errors) (Includes Vessel Flange Requirements of 150°F and 621 psi per 10CFR50)

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

.9-9-7 TA3LE 9-1 D.C Cook Unit 2 Reactor Vessel Heatup Curve Data Points for 32 EFPY Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150°F and 621 psi per 10CFR50)

Composite 60 Critical Limit 60 Leak Test Limit T (OF)

P (psie)

T (OF)

P (psig)

T (OF)

P (psig) 60 0

260 0

243 2000 60 588 260 588 260 2485 65 588 260 588 70 588 260 589 75 588 260 590 80 588 260 592 85 588 260 594 90 588 260 595 95 588 260 600 100 588 260 600 105 589 260 606 110 592 260 608 115 595 260 614 120 600 260 620 125 606 260 621 130 614 260 621 135 621 260 621 140 621 260 621 145 621 260 6211 150 621 260 656 150 656 260 670 155 670 260 686 t60 686 260 704 165 704 260 724 170 724 260 746 175 746 260 770 180 770 260 797 185 797 260 827 190 827 260 860 195 860 260 896 2_)0 896 260 936 205 936 260 981 210 981 260 1030 215 1030 260 1084 220 1084 265 1144 2

1144 01211 1211 275 1284 235 1284 280 j

1365 240 1365 285 1454 24 5 1454 290 1531 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

1611 250 1531 1

295 255 1611 300 1699 260 1699 305 1796 265 1796 310 1903 270 1903 315 2022 275 2022 320 2152 280 2152 325 2296 285 2296 330 2455 290 2455 1

1 1

j D C. Cook ULit 2 Heatup and Cooldown Limit Curves 9-8 9-8

9-9 TABLE 9-2 D.C Cook Unit 2 Reactor Vessel Cooldown Curne Data Points for 32 EFPY Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 1500F and 621 psi per 10CFRSO)

Steady State 20 oF/hr.

40oF/hr.

60°F/hr.

100 0F/hr.

T(oF)

P (psiO) I T(oF)

P (psig)

T(oF)

P (psig)

T(0 F)

P (psip)

T(0 F)

P (psig)]

60 0

60 0

60 0

60 0

60 0

60 621 60 578 60 529 60 479 60 376 65 621 65 580 65 532 65 482 65 379 70 621 70 583 70 534 70 485 70 382 75 621 75 586 75 537 75 488 75 386 80 621 80 589 80 541 80 492 80 390 85 621 85 593 85 545 85 496 85 395 90 621 90 597 90 549 90 500 90 400 95 1 621 95 602 95 5 54 95 506 95 406 100 621 100 607 100 559 100 511 100 413 105 621 105 613 105 566 105 1 518 105 421 110 621 110 619 I110 i

572 I10 5 25 110 429 115 621 115 621 115 580 115 533 115 439 120 621 120 621 120 588 120 542 120 450 125 621 125 621 125 597 125 552 125 462 130 621 130 621 130 608 130 564 130 475 135 621 135 621 135 619 135 576 135 490 140 621 140 6 621 140 621 140 590 140 507 145 621 145 621 145 621 145 605 145 526 150 621 150 621 150 621 150 623 150 547 150 741 150 701 150 662 155 642 155 570 155 756 155 717 155 679 160 663 160 596 160 772 160 735 160 698 165 686 165 625 165 789 165 7 754 165 720 170 713 170 657 170 809 170 776 170 743 175 741 175 693 175 831 175 799 175 770 180 774 180 733 18{

855 180 826 180 799 185 809 185 776 185 881 185 855 185 831 190 848 190 825 190 911 190 887 190 866 195 892 195 879 195 943 195 923 195 906 200 941 200 939 200 979 200 962 1

200 949 205 994 205 1006 205 I

1019 205 1006 205 998 210 1054 210 1062 210 1062 210 1054 210 1051 215 1108 l

215 1108 215 1111 215 1108 215 1108 220 1164 220 1164 220 1164 220 1164 220 1164 225 1223 225 1223 221 5 12 1223 225 1223 230 1288 230 1288 2301) 12881288 235 1361 235 1361 2 235 1361 235 1361 2335 1361 240 1440 240 1440

,240 1440 240 1440 240 1440 145 15 245 1528 245 1528 3 245 1528 250 1

1626 2_0 1621 2

250 t626 250 1626 I

250 1626

-255 1733 255 1733 D C Cook Unit 2 Heamp and Cooldown Limit Curves I-

9-10 255

• 1733 I

255 1733 255 1733 260 _

1852 l 260 1852 1 3 i

18 265098 260 18526 0 0 1852 260 1852 265 265 198 265 1984 265 1984 265 1984 270 2129 270 2129 270 2129 270 270 2 129 2 75 2289 275 2289 275 2

2*89 275 1229 275 i

2289 i

280 2467 280 2467 280 i

2467 280 2467 280 2467 i

DC. Cook Unit 2 Heatup and Cooldovwn Limit Curves

.I

9-11 TABLE 9-3 D.C Cook Unit 2 Reactor Vessel Heatup Curve Data Points for 48 EFPY Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150°F and 621 psi per 10CFRS0) 600F/hr. Heatup 60°F/hr. Criticality Leak Test Limit T(°F)

P (psig)

T(°F)

P (psig)

T(°F)

P (psig) 60 0

272 0

255 2000 60 575 272 575 272 2485 65 575 272 5

T 70 5

575 272 576 75 575 272 576 80 575 272 579 85 575 272 579 90 575 272 582 95 575 272 583 100 575 272 586 105 575 272 590 110 576 272 592 115 579 272 598 120 582 272 599 125 586 272 606 130 592 272 611 135 598 272 614 140 606 272 621 145 614 272 621 150 621 272 624 1

150 624 272 635 155 635 272 647 160 647 272 661 165 661 272 676 170 676 272 693 175 693 272 712 180 712 272 733 185 733 272 757 190 757 272 7821 195 782 272 811 200 811 43 20o 843 272 878 210 878 272 916 215 916

.2722 959 220 959 272 1006 225 1006 272 1058 230 1058 275 1115 235 1115 280 1179 240 1179 1 285 1249 2

_45 1249 290 1326 1

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

250 1

1326 295 1411 255 1411 300 1501 260 1501 305 1578 265 1578 310 1662 270 I

1662 315 1756 275 1756 320 1858 280 1858 325 1972 285 1972 330 2097 290 2097 335 2235 295 2235 340 2387 300 2387 D.C. Cook Unit 2 Heatup and Cooldown Limit Curves 9-1 9-12

-1 9-131 TABLE 9-4 DC. Cock Unit 2 Reactor Vessel CooldowNn Curve Data Points for 48 EFPY Without Margins for Instrumentation Errors (Includes Vessel Flange Requirements of 150cF and 621 psi per 10CFRS0)

Steady State 20 OF/hr.

400 F!hr.

60°F!hr.

100OF/hr.

T(-F)

P (psig)

T(oF)

P (psig)

T(°F)

P (psig)

T(°F)

P (psig)

T(OF)

P (psig) 60 0

60 0

60 0

60 0

60 0

60 621 60

_572 60 523 60 473 60 368 65 621 65 574 65 525 65 475 65 370 70 621 70 576 70 527 70 477 70 373 75 621 75 579 75 529 75 479 75 375 80 621 80 581 80 532 80 482 80 378 621 85 584 85 535 85 485 85 382 90 621 90 587 90 538 90 488 90 386 95 621 95 591 95 542 95 492 95 390 100 621 100 595 100 546 100 497 100 395 105 621 105 599 105 551 105 502 105 401 110 621 110 604 110 556 110 507 110 407 115 621 115 610 115 562 115 514 115 415 120 621 120 616 120 569 120 521 120 423 125 621 125 621 125 576 125 528 125 432 130 621 130 621 130 584 130 537 130 443 135 621 135 621 135 593 135 547 135 454 140 621 140 621 140 603 140 558 140 467 145 621 145 621 145 614 145 570 145 482 150 621 150 621 150 626 150 583 150 498 150 711 150 669 155 639 155 598 155 516 155 723 155 681 160 654 160 614 160

-536 160 736 160 695 165 671 165 63, t65 559 165 750 165 710 170 690 170 653 170 584 170 765 170 727 175 710 175 676 175 612 175 782 175 746 180 733 180 701 180 642 180 801 180 766 185 758 185 729 1

185 677 185 822 185 789 190 786 190 759 190 715 190 845 I 190 815 195 817 195 794 195 757 195 870 195 843 200 851 200 831 200 804 20O 899 200 874 205 889 205 874 0J; 5

205 930 205 908 210 931 210 920 210 914 210 964 210 946 1

977 215 97 2-15 972 215 1002 215 988 20 1029 2 20 1020 220 1029 220 1044 220 1034 t22 1086 2 25 1086 2 25 1086 2.1091 225 1086 230 1142 230 1142 230 i

1142 230 1142 230 1142 235 119Q 235 1199 235 t 6179 D C. Cook Unit 2 Heatup and Cooldown Limit Curves

9-14 235 1199 24240 12 62 245 1331 245 1331 1331 241 12 62 240 1262 1" 245 245 1331 245 1331 250 1407 250 1407 250 1407 250 1407 250 1407 255 1492 255 1492 255 1492 255 1492 255 92 2 260 1586 260 1586 260 1586 260 1586 260 1586 265 1689 265 1689 265 1689 265 1689 265 1689 270 1803 270 1803 270 1803 270 1803 270 1803 275 1929 275 1929 275 1929 275 1929 275 1929 280 2069 280 2069 280 2069 280 2069 280 2069 285 2223 285 2223 285 2223 285 1 2223 285 2223 290 2394 290 2394 290 2394 290 2394 290 2394 1

D.C. Cook Unit 2 Heatup and Cooldown Limit Curves

I I 10-I 10.0 ENABLE TEMPERATURE CALCULATION:

10. 1 ASME Code Case N-641 Methodology:

ASME Code Case N-6413 presents alternative procedures for calculating pressure-temperature relationships and low temperature overpressure protection (LTOP) system effective temperatures and allowable pressures. -These procedures take into account alternative fracture toughness properties, circumferential and axial reference flaws, and plant-specific LTOP effective temperature calculations.

ASME Code Case N-641 provides the following temperature condition to protect against failure during reactor startup and shutdown. The code requires that the LTOP or COMS system be effective at coolant temperatures less than 200OF or at coolant temperatures less than a temperature corresponding to a reactor vessel metal temperature calculated below:

(1) T, = RT.*rT 40 - max (ATerai), OF (2) Te = RTn.zcT 50 In [((F

• Mm (pR, / t)) - 33.2) / 20.734], OF,

where, Nlm = 0.926(t)/12), for an inside surface flaw (Ref. 3),

F

= 1.1, accumulation factor for safety relief valves (Ref 13) p

= 2.485, vessel design pressure, ksi (Section 6.1)

& = 173 / 2 = 86.5, vessel inner radius, in. (Section 6.1) t

= 8.5, vessel wall thickness, in. (Section 6. 1)

RTNDT is the highest adjusted reference temperature (ART) for the limiting beltline material at a distance one fourth of the vessel section thickness from the vessel inside surface (ie. clad/base metal interface), as determined by Regulatory Guide 1.99, Revision 2. The highest of the three temperatures determines the LTOP system effective temperature 10.2 32 EFPY Enable Temperature:

The highest calculated 1/4T ART for the D.C. Cook Unit 2 reactor vessel beltline regions at 32 EFPY is 200oF From the OPERLIM computer code output for the D.C. Cook Unit 2 32 EFPY Pressure-Temperature limit curves without margins the maximum ATmea is:

Cooldown Rate (Steady-State Cooldown):

max (ATme,!)

at 1/4T = O°F Heatup Rate of 60°F/Hrr max (,Tmei) at 1i4T = 17.902°F D.C. Cook Umit 2 Heatup and Cooldown Limit Curves

10-2 Enable Temperature. T- (1)

Enable Temperature, T, (2)

= RTN.-T - 40 + max (

OTr F),

°F

= (200 - 40 + 17.902) OF

= 257 902oF

= RT\\-,T - 50 ln[((F

• MN (pR, / t)) - 33.2) / 20.734]. OF

= 200 - 50 ln[((1.1 *.926(8.5)("'"'* 2.485

• 86.5 / 8.5)-33.2) / 20.734], OF

= 200 + 50 ln[41.90 / 20.734], OF

= 200 + 50 ln[2.021]

= 235.180OF The minimum required enable temperature for the D.C. Cook Unit 2 Reactor Vessels will be conservati,'ely chosen to be 260°F for 32 EFPY.

10.3 48 EFPY Enable Temperature:

The highest calculated 1/4T ART for the D.C. Cook Unit 2 reactor vessel beltline regions at 48 EFPY is 212 0F.

From the OPER.LIM computer code output for the D.C. Cook Unit 2 48 EFPY Pressure-Temperature limit curves without margins the maximum ATmeti is:

Cooldown Rate (Steady-State Cooldown):

max (AT,,t) at 1/4T = 0°F Heatup Rate of 60°FfHr:

max (ATinetal) at 1/4T = 17.902°F Enable Temperature (ENBT)

Enable Temperature, T, (2)

=

RTL 7 + 40 + max (ATmeui), OF

=

(212 + 40 - 17.902) °F

=

269. 902 0F

= RT-ý\\TD +50 ln[((F

• NI, (pR, / t)) - 33 2) / 20.734], OF

= 212 50 ln[((1.1 *.926(8.5)1':)

• 2.485

• 86.5 /8.5)-33.2) / 20734]. OF

= 12 -50 ln[41.90 / 20.7344]7 F

-212 + 50 ln[2.021]

=247. 180OF The minimum required enable temperature for the D.C. Cook Unit 2 Reactor Vessels w'ill be conservatively chosen to be 270 0 F for 48 EFPY.

D C Cook Unit 2 Heatup and Cooldown Limit Curves

li-I

11.0 REFERENCES

Regulatory Guide 1.99, Revision 2. "Radiation Embrittlement of Reactor Vessel Materials". U.S.

Nuclear Regulatory Commission. May, 1988.

10 CFR Part 50., Appendix G, "Fracture Toughness Requirements", Federal Register, Volume 60, No. 243, dated December 19, 1995.

ASME Boiler and Pressure Vessel Code.Section XI, "Rule for Inservice Inspection of Nuclear Power Plant Components", Appendix G, "Fracture Toughness Criteria for Protection Against Failure", December 1995.

4 WCAP-135 15, Revision 1, "Analysis of Capsule U from the Indiana Michigan Power Company D.C. Cook Unit 2 Reactor Vessel Radiation Surveillance Program", T J Laubham, et. al., dated April 2002 WCAP-85 12, "American Electric Power Company Donald C. Cook Unit No. 2 Reactor Vessel Radiation Surveillance Program", A. Davidson, et. al., November 1975.

6 SwRI Project No. 02-5928, "Reactor Vessel Material Surveillance Program for Donald C. Cook Unit No. 2 Analysis of Capsule T", E.B. Norris, September 16, 1981.

7 SwRI Project No. 06-7244-002, "Reactor Vessel Material Surveillance Program for Donald C.

Cook Unit No. 2 Analysis of Capsule Y", E.B. Norris, February 1984.

8 SwRI Project No. 06-8888, "Reactor Vessel Material Surveillance Program for Donald C. Cook Unit No. 2 Analysis of Capsule X", P.K. Nair, et. al., May 1987.

9ý 1989 Section III, Division 1 of the ASME Boiler and Pressure Vessel Code, Paragraph NB-233 1, "Material for Vessels" I0 WCAP-14040-NP-A. Revision 2. "Methodology used to Develop Cold Overpressure Mitigating System Setpoints and RCS Heatup and Cooldown Lirmt Curves". J. D. Andrachek, et al., January 1996.

it.

AEP Design Information Transrmttal (DIT), DIT-B-02230-00, "NMaterial Chemistry of the Reactor Vessel Belt-line Materials for Cook Nuclear Plant Units I & 2", T.Satyan-Sharma. 10/23/01.

12 Cases of ASME Boiler and Pressure Vessel Code, Case N-640, "Alternative Reference Fracture Toughness for Development of P-T Limit Curves for Section XI, Division I", Approved March 1999.

13 Cases of ASME Boiler and Pressure Vessel Code, Case N-641, "Altemative Pressure-Temperature Relationship and Low Temperature Overpressure Protection System Requirements," Approved 03,99 D.C. Cook nint 2 Heatup and Cooldown Lirruit Curves

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to AEP:NRC:2349-01 WCAP-13517, Revision 1 "Evaluation of Pressurized Thermal Shock for D. C. Cook Unit 2" Dated May 2002