ML23075A347

WCAP-18795-NP, Revision 0, Analysis of Capsule N from the Xcel Energy Prairie Island Unit 2 Reactor Vessel Radiation Surveillance Program, (Part 2 of 7)

ML23075A347
Person / Time
Site:	Prairie Island
Issue date:	12/31/2022
From:	Benson R, Long M Northern States Power Company, Minnesota, Westinghouse, Xcel Energy
To:	Office of Nuclear Reactor Regulation
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ML23075A344	List: L-PI-23-002, WCAP-18795-NP, Revision 0, Analysis of Capsule N from the Xcel Energy Prairie Island Unit 2 Reactor Vessel Radiation Surveillance Program, (Part 7 of 7) ML23075A345 ML23075A346 ML23075A347 ML23075A348 ML23075A349 ML23075A350 ML23075A351
References
L-PI-23-002 WCAP-18795-NP, Rev 0
Download: ML23075A347 (1)

Text

Westinghouse Non-Proprietary Class 3 6-1 6 RADIATION ANALYSIS AND NEUTRON DOSIMETRY

6.1 INTRODUCTION

This section describes a discrete ordinates (Sn) transport analysis performed for the Prairie Island Unit 2 reactor to determine the neutron radiation environment within the reactor pressure vessel and surveillance capsules. In this analysis, fast neutron exposure parameters in terms of fast neutron (E > 1.0 MeV) fluence and iron atom displacements (dpa) were established on a plant- and fuel-cycle-specific basis. An evaluation of the most recent dosimetry sensor set from Capsule N, withdrawn at the end of the 31st plant operating cycle, is provided. Comparison of the results from the dosimetry evaluations with the analytical predictions served to validate the plant-specific neutron transport calculations. These validated calculations subsequently form the basis for projections of the neutron exposure of the reactor pressure vessel for operating periods extending to 60 effective full-power years (EFPY).

The use of fast neutron (E > 1.0 MeV) fluence to correlate measured material property changes to the neutron exposure of the material has traditionally been accepted for the development of damage trend curves as well as for the implementation of trend curve data to assess the condition of the vessel. However, it has been suggested that an exposure model that accounts for differences in neutron energy spectra between surveillance capsule locations and positions within the vessel wall could lead to an improvement in the uncertainties associated with damage trend curves and improved accuracy in the evaluation of damage gradients through the reactor vessel wall.

Because of this potential shift away from a threshold fluence toward an energy-dependent damage function for data correlation, ASTM E853-18, Standard Practice for Analysis and Interpretation of Light-Water Reactor Surveillance Neutron Exposure Results [17], recommends reporting displacements per iron atom along with fluence (E > 1.0 MeV) to provide a database for future reference. The energy-dependent dpa function to be used for this evaluation is specified in ASTM E693-94, Standard Practice for Characterizing Neutron Exposures in Iron and Low Alloy Steels in Terms of Displacements per Atom (DPA) , E706 (ID)

[18]. The application of the dpa parameter to the assessment of embrittlement gradients through the thickness of the reactor vessel wall has been promulgated in Revision 2 to Regulatory Guide 1.99, Radiation Embrittlement of Reactor Vessel Materials [1].

All of the calculations and dosimetry evaluations described in this section and in Appendix A were based on nuclear cross-section data derived from ENDF/B-VI. Furthermore, the neutron transport and dosimetry evaluation methodologies follow the guidance of Regulatory Guide 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence [19]. Additionally, the methods used to develop the calculated pressure vessel fluence are consistent with the NRC-approved methodology described in WCAP-18124-NP-A, Fluence Determination with RAPTOR-M3G and FERRET [20] and WCAP-18124-NP-A Revision 0 Supplement 1, Fluence Determination with RAPTOR-M3G and FERRET

- Supplement for Extended Beltline Materials [21].

6.2 DISCRETE ORDINATES ANALYSIS The arrangement of the surveillance capsules in the Prairie Island Unit 2 reactor vessel is shown in Figure 4-1. Six irradiation capsules attached to the thermal shield are included in the reactor design that constitutes the reactor vessel surveillance program. Capsules S, T, V, N, P, and R are located at azimuthal angles of WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-2 57°, 67°, 77°, 237°, 247°, and 257°, respectively. These full-core positions correspond to the following octant symmetric locations represented in Figure 6-1 and Figure 6-2: 13°, 23°, and 33° from the core cardinal axes. The stainless steel specimen containers are approximately 1-inch square in cross section and are approximately 63 inches in height. The containers are positioned axially such that the test specimens are centered on the core midplane, thus spanning the central five feet of the 12-foot high reactor core.

From a neutronic standpoint, the surveillance capsules and associated support structures are significant.

The presence of these materials has a significant effect on both the spatial distribution of neutron exposure rate and the neutron spectrum in the vicinity of the capsules. However, the capsules are far enough apart that they do not interfere with one another. In order to determine the neutron environment at the test specimen location, the capsules themselves must be included in the analytical model.

In performing the fast neutron exposure evaluations for the Prairie Island Unit 2 reactor vessel and surveillance capsules, plant-specific 3D forward transport calculations were carried out to directly solve for the space- and energy-dependent neutron exposure rate, (r,,z,E).

For the Prairie Island Unit 2 transport calculations, the model depicted in Figure 6-1 and Figure 6-2 was utilized. The model contained a representation of the reactor core, the reactor internals, the pressure vessel cladding and vessel wall, the insulation external to the pressure vessel, and the primary biological shield wall. This model formed the basis for the calculated results. In developing this analytical model, nominal design dimensions were generally employed for the various structural components. In addition, water temperatures, and hence, coolant densities in the reactor core and downcomer regions of the reactor were taken to be representative of full-power operating conditions. The coolant densities were treated on a fuel-cycle-specific basis. Table 6-10 contains the cycle-specific power levels, inlet coolant temperatures, and core average temperatures used in this analysis. The reactor core itself was treated as a homogeneous mixture of fuel, cladding, water, and miscellaneous core structures, such as fuel assembly grids, guide tubes, etc.

Section views of the model are shown in Figure 6-3 and Figure 6-4. The model extends radially from the centerline of the reactor core out to a location interior to the primary biological shield and over an axial span from an elevation more than five feet below the active fuel to more than five feet above the active fuel.

The RAPTOR-M3G model consisted of 186 radial mesh, 200 azimuthal mesh, and 435 axial mesh. Mesh sizes were chosen to assure that proper convergence of the inner iterations was achieved on a pointwise basis. The pointwise inner iteration flux convergence criterion utilized in the calculations was set at a value of 0.001.

The core power distributions used in the plant-specific transport analysis for the first 32 fuel cycles at Prairie Island Unit 2 included cycle-dependent fuel assembly initial enrichments, burnups, radial and axial power distributions. Actual operating characteristics through Cycle 32 have been evaluated; projections beyond Cycle 32 were based on Cycle 32 spatial power distributions, water temperatures, and reactor power level with a 10% bias on the peripheral and re-entrant corner relative powers as directed by Xcel Energy. The cycle-dependent fuel assembly initial enrichments, burnups, radial and axial power distributions were used to develop spatial- and energy-dependent core source distributions averaged over each individual fuel cycle.

Therefore, the results from the neutron transport calculations provided data in terms of fuel-cycle-averaged neutron exposure rate, which when multiplied by the appropriate fuel cycle length, generated the WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-3 incremental fast neutron exposure for each fuel cycle. In constructing these core source distributions, the energy distribution of the source was based on an appropriate fission split for uranium and plutonium isotopes based on the initial enrichment and burnup history of individual fuel assemblies. From these assembly-dependent fission splits, composite values of energy release per fission, neutron yield per fission, and fission spectrum were determined.

All of the transport calculations supporting this analysis were carried out using the RAPTOR-M3G discrete ordinates code and the BUGLE-96 cross-section library, as described in Westinghouse Report WCAP-18124-NP-A [20]. The BUGLE-96 library provides a coupled 47-neutron, 20-gamma-group cross-section data set produced specifically for light-water reactor (LWR) applications. In these analyses, anisotropic scattering was treated with a P3 Legendre expansion, and angular discretization was modeled with an S16 order of angular quadrature. Energy- and space-dependent core power distributions, as well as system operating temperatures, were treated on a fuel-cycle-specific basis.

Results of the discrete ordinates transport analyses pertinent to the surveillance capsule evaluations are provided in Table 6-1 through Table 6-3. In Table 6-1, the calculated fast neutron fluence rate and fluence (E > 1.0 MeV) are provided at the geometric center of the capsules, as a function of irradiation time for the Prairie Island Unit 2 reactor. Similar data presented in terms of iron atom displacement rate and integrated iron atom displacements are given in Table 6-2. Note that the fluence values for the surveillance capsules are different than the previous report. This is largely due to the updated methodology used in determining the fluence values. The previous values were determined using 2D adjoint transport methods. This analysis employed 3D forward transport methods.

In Table 6-3, lead factors associated with surveillance capsules are provided as a function of operating time for the Prairie Island Unit 2 reactor. The lead factor is defined as the ratio of the neutron fluence (E > 1.0 MeV) at the geometric center of the surveillance capsule to the maximum neutron fluence (E > 1.0 MeV) at the pressure vessel clad/base metal interface.

Neutron exposure data pertinent to the pressure vessel clad/base metal interface are given in Table 6-4 and Table 6-5 for neutron fluence (E > 1.0 MeV) rate and fluence (E > 1.0 MeV), respectively, and in Table 6-6 and Table 6-7 for dpa/s and dpa, respectively. In each case, the data are provided for each operating cycle of the Prairie Island Unit 2 reactor. Neutron fluence (E > 1.0 MeV) and dpa are also projected to future operating times extending to 60 EFPY. The vessel exposure data are presented in terms of the maximum exposure experienced by the pressure vessel at azimuthal angles of 0°, 15°, 30°, and 45°, and at the azimuthal location providing the maximum exposure relative to the core cardinal axes.

In Table 6-8 and Table 6-9, maximum projected fluences and dpa, respectively, of the various pressure vessel materials are given.

These data tabulations include both plant- and fuel-cycle-specific calculated neutron exposures at the end of Cycle 32 and projections to 60 EFPY. The projections beyond Cycle 32 were based on Cycle 32 spatial power distributions, water temperatures, and reactor power level with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-4 6.3 NEUTRON DOSIMETRY The validity of the calculated neutron exposures reported in Section 6.2 is demonstrated by a direct comparison against the measured sensor reaction rates and a least-squares evaluation performed for each of the capsule dosimetry sets. However, since the neutron dosimetry measurement data merely serve to validate the calculated results, only the direct comparison of measured-to-calculated results for the most recent surveillance capsule removed from Prairie Island Unit 2, Capsule N, is provided in this section of the report. For completeness, the assessment of all measured dosimetry removed from Prairie Island Unit 2 up to date based on both direct and least-squares evaluation comparisons is documented in Appendix A.

The direct comparison of measured versus calculated fast neutron threshold reaction rates for the sensors from Capsule N, that was withdrawn from the reactor at the conclusion of Cycle 31, is summarized below.

Reaction Rate (rps/atom)

Reaction M/C Measured Calculated 63 Cu (n,) 60Co 3.47E-17 4.23E-17 0.82 54 Fe (n,p) 54Mn 3.56E-15 4.57E-15 0.78 58 Ni (n,p) 58Co 6.28E-15 6.30E-15 1.00 238 U(Cd) (n,f) 137Cs 2.23E-14 2.25E-14 0.99 237 Np(Cd) (n,f) 137Cs 1.85E-13 1.82E-13 1.02 59 Co (n,) 60Co 3.02E-12 3.98E-12 0.76 Average of M/C Results 0.92 Standard Deviation (%) 12.2 The measured-to-calculated (M/C) reaction rate ratios for the Capsule N threshold reactions range from 0.78 to 1.02, and the average M/C ratio is 0.92 12.2% (1). This direct comparison falls within the 20%

criterion specified in Regulatory Guide 1.190. This comparison validates the current analytical results described in Section 6.2; therefore, the calculations are deemed applicable for Prairie Island Unit 2.

6.4 CALCULATIONAL UNCERTAINTIES The uncertainty associated with the calculated neutron exposure of the Prairie Island Unit 2 surveillance capsule and reactor pressure vessel is based on the recommended approach provided in Regulatory Guide 1.190. In particular, the qualification of the methodology was carried out in the following four stages:

1. Simulator Benchmark Comparisons: Comparisons of calculations with measurements from simulator benchmarks, including the Pool Critical Assembly (PCA) simulator at the Oak Ridge National Laboratory (ORNL) and the VENUS-1 Experiment.

2. Operating Reactor and Calculational Benchmarks: Comparisons of calculations with surveillance capsule and reactor cavity measurements from the H.B. Robinson power reactor WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 6-5 benchmark experiment. Also considered are comparisons of calculations to results published in the NRC fluence calculation benchmark.

3. Analytic Uncertainty Analysis: An analytical sensitivity study addressing the uncertainty components resulting from important input parameters applicable to the plant-specific transport calculations used in the neutron exposure assessments.

4. Plant-Specific Benchmarking: Comparisons of the plant-specific calculations with all available dosimetry results from the Prairie Island Unit 2 surveillance program.

The first phase of the methods qualification (simulator benchmark comparisons) addressed the adequacy of basic transport calculation and dosimetry evaluation techniques and associated cross-sections. This phase, however, did not test the accuracy of commercial core neutron source calculations nor did it address uncertainties in operational or geometric variables that impact power reactor calculations. The second phase of the qualification (operating reactor and calculational benchmark comparisons) addressed uncertainties in these additional areas that are primarily methods-related and would tend to apply generically to all fast neutron exposure evaluations. The third phase of the qualification (analytical sensitivity study) identified the potential uncertainties introduced into the overall evaluation due to calculational methods approximations, as well as to a lack of knowledge relative to various plant-specific input parameters. The overall calculational uncertainty applicable to the Prairie Island Unit 2 analysis was established from results of these three phases of the methods qualification.

The fourth phase of the uncertainty assessment (comparisons with Prairie Island Unit 2 measurements) was used solely to demonstrate the validity of the transport calculations and to confirm the uncertainty estimates associated with the analytical results. The comparison was used only as a check and was not used in any way to modify the calculated surveillance capsule and pressure vessel neutron exposures described in Section 6.2. As such, the validation of the Prairie Island Unit 2 analytical model based on the measured plant dosimetry is completely described in Appendix A.

The following summarizes the uncertainties developed from the first three phases of the methodology qualification. Additional information pertinent to these evaluations is provided in Westinghouse Report WCAP-18124-NP-A [20].

Description Capsule and Vessel IR Simulator Benchmark Comparisons 3%

Operating Reactor and Calculational Benchmarks 5%

Analytic Uncertainty Analysis 11%

Additional Uncertainty for Factors not Explicitly Evaluated 5%

Net Calculational Uncertainty 13%

The net calculational uncertainty was determined by combining the individual components in quadrature.

Therefore, the resultant uncertainty was treated as random, and no systematic bias was applied to the analytical results. The plant-specific measurement comparisons described in Appendix A support these uncertainty assessments for Prairie Island Unit 2.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-6 The NRC-issued Safety Evaluation for WCAP-18124-NP-A appears in Section A of [20]. The NRC identified two Limitations and Conditions associated with the application of RAPTOR-M3G and FERRET, which are reproduced here for convenience:

1. Applicability of WCAP-18124-NP, Revision 0 is limited to the RPV region near the active height of the core based on the uncertainty analysis performed and the measurement data provided.

Additional justification should be provided via additional benchmarking, fluence sensitivity analysis to the response parameters of interest (e.g., pressure-temperature limits, material stress/strain), margin assessment, or a combination thereof, for applications of the method to components including, but not limited to, the RPV upper circumferential weld and the reactor coolant system inlet and outlet nozzles and reactor vessel internal components.

2. Least squares adjustment is acceptable if the adjustments to the M/C ratios and to the calculated spectra values are within the assigned uncertainties of the calculated spectra, the dosimetry measured reaction rates, and the dosimetry reaction cross sections. Should this not be the case, the user should re-examine both measured and calculated values for possible errors. If errors cannot be found, the particular values causing the discrepancy should be disqualified.

The neutron exposure values applicable to the surveillance capsules and the maximum reactor pressure vessel neutron exposure values used to derive the surveillance capsule lead factors are completely covered by the benchmarking and uncertainty analyses in WCAP-18124-NP-A. Note, however, that this report does contain neutron exposure values for materials that are outside the qualification basis of WCAP-18124-NP-A (i.e. extended beltline materials). For the materials considered to be located in the extended beltline region, a comprehensive analytical uncertainty analysis applicable to the Prairie Island Unit 2 RPV extended beltline region is summarized in WCAP18124-NP-A, Revision 0, Supplement 1-NP-A [21]. All RPV extended beltline calculations for Prairie Island Unit 2 were performed using the WCAP-18124-NP-A, Revision 0, Supplement 1-NP-A methodology.

Limitation # 2 applies in situations where the least-squares analysis is used to adjust the calculated values of neutron exposure. In this report, the least-squares analysis is provided only as a supplemental check on the results of the dosimetry evaluation. The least-squares analysis was not used to modify the calculated surveillance capsule or reactor pressure vessel neutron exposure. Therefore, Limitation # 2 does not apply.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-7 Table 6-1 Calculated Maximum Fast (E > 1.0 MeV) Neutron Fluence Rate and Fluence at Surveillance Capsule Locations Cycle Total Fluence Rate (n/cm2-s)

Cycle Length Time 13° 23° 33° (EFPY) (EFPY) 1 1.39 1.39 1.36E+11 7.79E+10 7.48E+10 2 0.87 2.26 1.45E+11 8.68E+10 8.40E+10 3 0.89 3.15 1.50E+11 8.91E+10 8.71E+10 4 0.98 4.13 1.51E+11 8.84E+10 8.46E+10 5 0.92 5.05 1.58E+11 9.03E+10 8.74E+10 6 0.99 6.04 1.49E+11 7.93E+10 7.12E+10 7 1.01 7.05 1.43E+11 8.20E+10 7.62E+10 8 0.90 7.95 1.25E+11 7.61E+10 7.06E+10 9 0.85 8.80 1.82E+11 9.43E+10 8.63E+10 10 0.92 9.71 1.58E+11 9.42E+10 9.12E+10 11 1.09 10.80 1.48E+11 8.63E+10 8.25E+10 12 1.08 11.88 1.26E+11 8.51E+10 8.57E+10 13 1.26 13.15 9.40E+10 6.46E+10 6.25E+10 14 1.33 14.47 8.76E+10 6.11E+10 6.11E+10 15 1.38 15.86 8.99E+10 5.67E+10 5.52E+10 16 1.38 17.24 9.43E+10 7.13E+10 6.69E+10 17 1.55 18.78 8.79E+10 6.56E+10 5.87E+10 18 1.48 20.27 8.37E+10 5.78E+10 5.47E+10 19 1.30 21.57 8.10E+10 6.50E+10 6.10E+10 20 1.56 23.13 9.53E+10 6.84E+10 6.04E+10 21 1.52 24.64 8.87E+10 6.30E+10 5.54E+10 22 1.48 26.12 8.86E+10 6.17E+10 5.81E+10 23 1.37 27.49 8.95E+10 6.00E+10 5.77E+10 24 1.72 29.21 8.69E+10 5.77E+10 5.48E+10 25 1.44 30.66 8.60E+10 5.94E+10 5.99E+10 26 1.68 32.34 8.87E+10 5.82E+10 5.74E+10 27 1.24 33.58 9.32E+10 6.10E+10 6.06E+10 28 1.65 35.24 9.35E+10 6.04E+10 5.70E+10 29 1.64 36.88 9.36E+10 6.14E+10 6.10E+10 30 1.85 38.73 8.86E+10 6.10E+10 6.21E+10 31 1.91 40.64 9.20E+10 5.91E+10 5.77E+10 32 1.95 42.59 9.15E+10 6.04E+10 6.01E+10 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-8 Table 6-1 Calculated Maximum Fast (E > 1.0 MeV) Neutron Fluence Rate and Fluence at Surveillance Capsule Locations (cont.)

Total Fluence (n/cm2)

Cycle Time V T R P N S (EFPY) (13°) (23°) (13°) (23°) (33°) (33°)

1 1.39 5.98E+18 3.42E+18 5.98E+18 3.42E+18 3.29E+18 3.29E+18 2 2.26 5.81E+18 9.97E+18 5.81E+18 5.59E+18 5.59E+18 3 3.15 8.30E+18 1.42E+19 8.30E+18 8.03E+18 8.03E+18 4 4.13 1.10E+19 1.88E+19 1.10E+19 1.06E+19 1.06E+19 5 5.05 2.34E+19 1.37E+19 1.32E+19 1.32E+19 6 6.04 2.81E+19 1.61E+19 1.54E+19 1.54E+19 7 7.05 3.26E+19 1.88E+19 1.78E+19 1.78E+19 8 7.95 3.62E+19 2.09E+19 1.98E+19 1.98E+19 9 8.80 4.11E+19 2.34E+19 2.22E+19 2.22E+19 10 9.71 2.62E+19 2.48E+19 2.48E+19 11 10.80 2.91E+19 2.76E+19 2.76E+19 12 11.88 3.20E+19 3.05E+19 3.05E+19 13 13.15 3.46E+19 3.30E+19 3.30E+19 14 14.47 3.72E+19 3.56E+19 3.56E+19 15 15.86 3.96E+19 3.80E+19 3.80E+19 16 17.24 4.27E+19 4.09E+19 4.09E+19 17 18.78 4.38E+19 4.38E+19 18 20.27 4.64E+19 4.64E+19 19 21.57 4.89E+19 4.89E+19 20 23.13 5.18E+19 5.18E+19 21 24.64 5.45E+19 5.45E+19 22 26.12 5.72E+19 5.72E+19 23 27.49 5.97E+19 5.97E+19 24 29.21 6.27E+19 6.27E+19 25 30.66 6.54E+19 6.54E+19 26 32.34 6.84E+19 6.84E+19 27 33.58 7.08E+19 7.08E+19 28 35.24 7.38E+19 7.38E+19 29 36.88 7.69E+19 7.69E+19 30 38.73 8.06E+19 8.06E+19 31 40.64 8.41E+19 8.41E+19 32 42.59 8.77E+19 48 9.90E+19 51 1.05E+20 54 1.11E+20 60 1.24E+20 Note:

1. Values beyond Cycle 32 are projected based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-9 Table 6-2 Calculated Iron Atom Displacement Rate and Iron Atom Displacements at Surveillance Capsule Locations Cycle Total Iron Atom Displacement Rate Cycle Length Time (dpa/s)

(EFPY) (EFPY) 13-degree 23-degree 33-degree 1 1.39 1.39 2.49E-10 1.37E-10 1.32E-10 2 0.87 2.26 2.66E-10 1.52E-10 1.48E-10 3 0.89 3.15 2.75E-10 1.56E-10 1.54E-10 4 0.98 4.13 2.77E-10 1.55E-10 1.49E-10 5 0.92 5.05 2.90E-10 1.58E-10 1.54E-10 6 0.99 6.04 2.73E-10 1.39E-10 1.25E-10 7 1.01 7.05 2.62E-10 1.44E-10 1.34E-10 8 0.90 7.95 2.29E-10 1.33E-10 1.24E-10 9 0.85 8.80 3.34E-10 1.66E-10 1.52E-10 10 0.92 9.71 2.89E-10 1.65E-10 1.61E-10 11 1.09 10.80 2.70E-10 1.51E-10 1.45E-10 12 1.08 11.88 2.30E-10 1.49E-10 1.51E-10 13 1.26 13.15 1.71E-10 1.13E-10 1.10E-10 14 1.33 14.47 1.59E-10 1.06E-10 1.07E-10 15 1.38 15.86 1.63E-10 9.88E-11 9.69E-11 16 1.38 17.24 1.71E-10 1.24E-10 1.17E-10 17 1.55 18.78 1.59E-10 1.14E-10 1.03E-10 18 1.48 20.27 1.52E-10 1.00E-10 9.59E-11 19 1.30 21.57 1.47E-10 1.13E-10 1.07E-10 20 1.56 23.13 1.73E-10 1.19E-10 1.06E-10 21 1.52 24.64 1.61E-10 1.09E-10 9.72E-11 22 1.48 26.12 1.61E-10 1.07E-10 1.02E-10 23 1.37 27.49 1.62E-10 1.04E-10 1.01E-10 24 1.72 29.21 1.58E-10 1.00E-10 9.61E-11 25 1.44 30.66 1.56E-10 1.03E-10 1.05E-10 26 1.68 32.34 1.61E-10 1.01E-10 1.01E-10 27 1.24 33.58 1.69E-10 1.06E-10 1.06E-10 28 1.65 35.24 1.70E-10 1.05E-10 9.99E-11 29 1.64 36.88 1.70E-10 1.07E-10 1.07E-10 30 1.85 38.73 1.61E-10 1.06E-10 1.09E-10 31 1.91 40.64 1.67E-10 1.03E-10 1.01E-10 32 1.95 42.59 1.66E-10 1.05E-10 1.05E-10 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-10 Table 6-2 Calculated Iron Atom Displacement Rate and Iron Atom Displacements at Surveillance Capsule Locations (cont.)

Total Iron Atom Displacements (dpa)

Cycle Time V T R P N S (EFPY) (13°) (23°) (13°) (23°) (33°) (33°)

1 1.39 1.10E-02 6.00E-03 1.10E-02 6.00E-03 5.79E-03 5.79E-03 2 2.26 1.02E-02 1.83E-02 1.02E-02 9.86E-03 9.86E-03 3 3.15 1.46E-02 2.60E-02 1.46E-02 1.42E-02 1.42E-02 4 4.13 1.93E-02 3.45E-02 1.93E-02 1.88E-02 1.88E-02 5 5.05 4.29E-02 2.39E-02 2.32E-02 2.32E-02 6 6.04 5.15E-02 2.83E-02 2.72E-02 2.72E-02 7 7.05 5.98E-02 3.29E-02 3.14E-02 3.14E-02 8 7.95 6.63E-02 3.66E-02 3.50E-02 3.50E-02 9 8.80 7.53E-02 4.11E-02 3.90E-02 3.90E-02 10 9.71 4.58E-02 4.37E-02 4.37E-02 11 10.80 5.10E-02 4.87E-02 4.87E-02 12 11.88 5.61E-02 5.38E-02 5.38E-02 13 13.15 6.06E-02 5.82E-02 5.82E-02 14 14.47 6.50E-02 6.27E-02 6.27E-02 15 15.86 6.93E-02 6.69E-02 6.69E-02 16 17.24 7.47E-02 7.20E-02 7.20E-02 17 18.78 7.71E-02 7.71E-02 18 20.27 8.16E-02 8.16E-02 19 21.57 8.60E-02 8.60E-02 20 23.13 9.12E-02 9.12E-02 21 24.64 9.58E-02 9.58E-02 22 26.12 1.01E-01 1.01E-01 23 27.49 1.05E-01 1.05E-01 24 29.21 1.10E-01 1.10E-01 25 30.66 1.15E-01 1.15E-01 26 32.34 1.20E-01 1.20E-01 27 33.58 1.24E-01 1.24E-01 28 35.24 1.30E-01 1.30E-01 29 36.88 1.35E-01 1.35E-01 30 38.73 1.42E-01 1.42E-01 31 40.64 1.48E-01 1.48E-01 32 42.59 1.54E-01 48 1.74E-01 51 1.85E-01 54 1.96E-01 60 2.18E-01 Note:

1. Values beyond Cycle 32 are projected based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-11 Table 6-3 Calculated Surveillance Capsule Lead Factors Cycle Total Lead Factor Length Time Cycle (EFPY) (EFPY) 13° 23° 33° 1 1.39 1.39 3.031 1.73 1.66 2 0.87 2.26 3.06 1.78 1.72 3 0.89 3.15 3.08 1.80 1.74 4 0.98 4.13 3.08 1.802 1.74 5 0.92 5.05 3.07 1.79 1.73 6 0.99 6.04 3.07 1.76 1.68 7 1.01 7.05 3.11 1.78 1.70 8 0.90 7.95 3.09 1.78 1.69 9 0.85 8.80 3.083 1.76 1.66 10 0.92 9.71 3.08 1.77 1.68 11 1.09 10.80 3.07 1.76 1.67 12 1.08 11.88 3.08 1.80 1.71 13 1.26 13.15 3.09 1.82 1.74 14 1.33 14.47 3.09 1.84 1.76 15 1.38 15.86 3.09 1.85 1.77 16 1.38 17.24 3.11 1.884 1.80 17 1.55 18.78 3.12 1.92 1.83 18 1.48 20.27 3.13 1.93 1.84 19 1.30 21.57 3.14 1.97 1.87 20 1.56 23.13 3.15 1.99 1.89 21 1.52 24.64 3.16 2.01 1.89 22 1.48 26.12 3.16 2.02 1.90 23 1.37 27.49 3.16 2.02 1.91 24 1.72 29.21 3.16 2.02 1.91 25 1.44 30.66 3.16 2.02 1.92 26 1.68 32.34 3.15 2.02 1.92 27 1.24 33.58 3.15 2.02 1.92 28 1.65 35.24 3.15 2.02 1.92 29 1.64 36.88 3.15 2.03 1.93 30 1.85 38.73 3.16 2.04 1.94 31 1.91 40.64 3.15 2.03 1.945 32 1.95 42.59 3.15 2.04 1.95 48 3.15 2.04 1.96 51 3.15 2.04 1.97 54 3.15 2.04 1.97 60 3.15 2.04 1.98 Notes:

1. Capsule V was removed after Cycle 1.

2. Capsule T was removed after Cycle 4.

3. Capsule R was removed after Cycle 9.

4. Capsule P was removed after Cycle 16.

5. Capsule N was removed after Cycle 31.

6. The projections beyond Cycle 32 are based on Cycle 32 with a 10% bias on peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-12 Table 6-4 Calculated Maximum Fast (E > 1.0 MeV) Neutron Fluence Rate at the Pressure Vessel Clad/Base Metal Interface Fluence Rate (n/cm2-s)

Cycle Total Elevation Cycle Length Time 0° 15° 30° 45° Maximum of Max.

(EFPY) (EFPY) (cm) 1 1.39 1.39 4.49E+10 2.69E+10 1.77E+10 1.55E+10 4.49E+10 -9 2 0.87 2.26 4.75E+10 2.93E+10 2.01E+10 1.73E+10 4.75E+10 73 3 0.89 3.15 4.83E+10 2.97E+10 2.05E+10 1.80E+10 4.83E+10 -1 4 0.98 4.13 4.90E+10 3.00E+10 2.01E+10 1.72E+10 4.90E+10 5 5 0.92 5.05 5.19E+10 3.11E+10 2.06E+10 1.84E+10 5.19E+10 -3 6 0.99 6.04 5.03E+10 2.98E+10 1.74E+10 1.62E+10 5.03E+10 59 7 1.01 7.05 4.24E+10 2.84E+10 1.82E+10 1.75E+10 4.24E+10 -3 8 0.90 7.95 4.28E+10 2.53E+10 1.70E+10 1.47E+10 4.28E+10 -3 9 0.85 8.80 5.98E+10 3.53E+10 2.06E+10 1.92E+10 5.98E+10 -3 10 0.92 9.71 5.07E+10 3.13E+10 2.15E+10 1.85E+10 5.07E+10 5 11 1.09 10.80 5.06E+10 2.96E+10 1.95E+10 1.89E+10 5.06E+10 5 12 1.08 11.88 3.87E+10 2.60E+10 2.01E+10 1.89E+10 3.87E+10 5 13 1.26 13.15 2.96E+10 1.97E+10 1.50E+10 1.33E+10 2.96E+10 5 14 1.33 14.47 2.79E+10 1.84E+10 1.45E+10 1.29E+10 2.79E+10 73 15 1.38 15.86 2.95E+10 1.85E+10 1.32E+10 1.26E+10 2.95E+10 5 16 1.38 17.24 2.78E+10 2.02E+10 1.62E+10 1.41E+10 2.78E+10 5 17 1.55 18.78 2.61E+10 1.89E+10 1.45E+10 1.21E+10 2.61E+10 5 18 1.48 20.27 2.56E+10 1.76E+10 1.32E+10 1.19E+10 2.56E+10 5 19 1.30 21.57 2.27E+10 1.76E+10 1.48E+10 1.26E+10 2.27E+10 5 20 1.56 23.13 2.87E+10 2.03E+10 1.50E+10 1.19E+10 2.87E+10 67 21 1.52 24.64 2.69E+10 1.89E+10 1.38E+10 1.16E+10 2.69E+10 67 22 1.48 26.12 2.75E+10 1.86E+10 1.41E+10 1.24E+10 2.76E+10 67 23 1.37 27.49 2.87E+10 1.86E+10 1.38E+10 1.26E+10 2.87E+10 67 24 1.72 29.21 2.86E+10 1.80E+10 1.31E+10 1.14E+10 2.86E+10 3 25 1.44 30.66 2.76E+10 1.79E+10 1.41E+10 1.28E+10 2.76E+10 -73 26 1.68 32.34 2.93E+10 1.83E+10 1.36E+10 1.28E+10 2.93E+10 -73 27 1.24 33.58 3.02E+10 1.92E+10 1.44E+10 1.32E+10 3.02E+10 -73 28 1.65 35.24 2.97E+10 1.91E+10 1.36E+10 1.22E+10 2.97E+10 -3 29 1.64 36.88 2.88E+10 1.91E+10 1.44E+10 1.31E+10 2.88E+10 -3 30 1.85 38.73 2.76E+10 1.83E+10 1.46E+10 1.34E+10 2.76E+10 -73 31 1.91 40.64 2.96E+10 1.88E+10 1.37E+10 1.21E+10 2.96E+10 -73 32 1.95 42.59 2.93E+10 1.88E+10 1.42E+10 1.29E+10 2.93E+10 -3 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-13 Table 6-5 Calculated Maximum Fast (E > 1.0 MeV) Neutron Fluence at the Pressure Vessel Clad/Base Metal Interface Fluence (n/cm2)

Cycle Total Elevation Cycle Length Time 0° 15° 30° 45° Maximum of Max.

(EFPY) (EFPY)

(cm) 1 1.39 1.39 1.98E+18 1.18E+18 7.78E+17 6.81E+17 1.98E+18 -9 2 0.87 2.26 3.25E+18 1.97E+18 1.32E+18 1.15E+18 3.25E+18 -3 3 0.89 3.15 4.60E+18 2.81E+18 1.90E+18 1.65E+18 4.60E+18 -3 4 0.98 4.13 6.12E+18 3.73E+18 2.52E+18 2.18E+18 6.12E+18 -1 5 0.92 5.05 7.62E+18 4.63E+18 3.11E+18 2.72E+18 7.62E+18 -3 6 0.99 6.04 9.15E+18 5.55E+18 3.65E+18 3.22E+18 9.15E+18 -1 7 1.01 7.05 1.05E+19 6.45E+18 4.23E+18 3.78E+18 1.05E+19 -1 8 0.9 7.95 1.17E+19 7.17E+18 4.71E+18 4.19E+18 1.17E+19 -1 9 0.85 8.8 1.33E+19 8.12E+18 5.26E+18 4.71E+18 1.33E+19 -1 10 0.92 9.71 1.48E+19 9.02E+18 5.89E+18 5.24E+18 1.48E+19 -1 11 1.09 10.8 1.65E+19 1.00E+19 6.56E+18 5.89E+18 1.65E+19 -1 12 1.08 11.88 1.78E+19 1.09E+19 7.24E+18 6.54E+18 1.78E+19 1 13 1.26 13.15 1.90E+19 1.17E+19 7.84E+18 7.07E+18 1.90E+19 3 14 1.33 14.47 2.02E+19 1.25E+19 8.45E+18 7.61E+18 2.02E+19 3 15 1.38 15.86 2.15E+19 1.33E+19 9.02E+18 8.16E+18 2.15E+19 3 16 1.38 17.24 2.27E+19 1.42E+19 9.73E+18 8.77E+18 2.27E+19 3 17 1.55 18.78 2.39E+19 1.51E+19 1.04E+19 9.36E+18 2.39E+19 3 18 1.48 20.27 2.51E+19 1.59E+19 1.11E+19 9.92E+18 2.51E+19 3 19 1.3 21.57 2.61E+19 1.66E+19 1.17E+19 1.04E+19 2.61E+19 3 20 1.56 23.13 2.75E+19 1.76E+19 1.24E+19 1.10E+19 2.75E+19 5 21 1.52 24.64 2.88E+19 1.85E+19 1.31E+19 1.16E+19 2.88E+19 5 22 1.48 26.12 3.00E+19 1.94E+19 1.37E+19 1.22E+19 3.00E+19 5 23 1.37 27.49 3.13E+19 2.02E+19 1.43E+19 1.27E+19 3.13E+19 5 24 1.72 29.21 3.28E+19 2.12E+19 1.50E+19 1.33E+19 3.28E+19 5 25 1.44 30.66 3.41E+19 2.20E+19 1.57E+19 1.39E+19 3.41E+19 5 26 1.68 32.34 3.56E+19 2.29E+19 1.64E+19 1.46E+19 3.56E+19 5 27 1.24 33.58 3.68E+19 2.37E+19 1.69E+19 1.51E+19 3.68E+19 5 28 1.65 35.24 3.83E+19 2.47E+19 1.77E+19 1.57E+19 3.83E+19 3 29 1.64 36.88 3.98E+19 2.57E+19 1.84E+19 1.64E+19 3.98E+19 3 30 1.85 38.73 4.15E+19 2.68E+19 1.92E+19 1.72E+19 4.15E+19 3 31 1.91 40.64 4.32E+19 2.79E+19 2.01E+19 1.79E+19 4.32E+19 3 32 1.95 42.59 4.50E+19 2.90E+19 2.09E+19 1.87E+19 4.50E+19 3 48 5.05E+19 3.25E+19 2.36E+19 2.11E+19 5.05E+19 3 51 5.35E+19 3.45E+19 2.50E+19 2.24E+19 5.35E+19 3 54 5.66E+19 3.64E+19 2.65E+19 2.38E+19 5.66E+19 3 60 6.26E+19 4.03E+19 2.94E+19 2.64E+19 6.26E+19 3 Note:

1. Projections are based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-14 Table 6-6 Calculated Maximum Iron Atom Displacement Rate at the Pressure Vessel Clad/Base Metal Interface Displacement Rate (dpa/s)

Cycle Total Elevation Cycle Length Time 0° 15° 30° 45° Maximum of Max.

(EFPY) (EFPY)

(cm) 1 1.39 1.39 7.37E-11 4.44E-11 2.89E-11 2.52E-11 7.37E-11 -9 2 0.87 2.26 7.79E-11 4.84E-11 3.28E-11 2.82E-11 7.79E-11 73 3 0.89 3.15 7.92E-11 4.91E-11 3.35E-11 2.93E-11 7.92E-11 -1 4 0.98 4.13 8.04E-11 4.95E-11 3.27E-11 2.80E-11 8.04E-11 5 5 0.92 5.05 8.51E-11 5.14E-11 3.36E-11 3.00E-11 8.51E-11 -3 6 0.99 6.04 8.25E-11 4.93E-11 2.84E-11 2.64E-11 8.25E-11 57 7 1.01 7.05 6.95E-11 4.68E-11 2.97E-11 2.84E-11 6.95E-11 -3 8 0.90 7.95 7.01E-11 4.18E-11 2.77E-11 2.39E-11 7.01E-11 -3 9 0.85 8.80 9.82E-11 5.83E-11 3.37E-11 3.13E-11 9.82E-11 -3 10 0.92 9.71 8.32E-11 5.17E-11 3.51E-11 3.02E-11 8.32E-11 5 11 1.09 10.80 8.28E-11 4.88E-11 3.19E-11 3.07E-11 8.28E-11 5 12 1.08 11.88 6.34E-11 4.28E-11 3.28E-11 3.08E-11 6.34E-11 9 13 1.26 13.15 4.85E-11 3.23E-11 2.44E-11 2.16E-11 4.85E-11 5 14 1.33 14.47 4.56E-11 3.02E-11 2.36E-11 2.10E-11 4.56E-11 73 15 1.38 15.86 4.83E-11 3.05E-11 2.14E-11 2.05E-11 4.83E-11 9 16 1.38 17.24 4.55E-11 3.32E-11 2.64E-11 2.29E-11 4.55E-11 5 17 1.55 18.78 4.27E-11 3.10E-11 2.36E-11 1.97E-11 4.27E-11 5 18 1.48 20.27 4.18E-11 2.89E-11 2.15E-11 1.93E-11 4.18E-11 5 19 1.30 21.57 3.72E-11 2.89E-11 2.41E-11 2.05E-11 3.72E-11 5 20 1.56 23.13 4.70E-11 3.33E-11 2.44E-11 1.94E-11 4.70E-11 65 21 1.52 24.64 4.40E-11 3.10E-11 2.24E-11 1.89E-11 4.40E-11 65 22 1.48 26.12 4.50E-11 3.06E-11 2.29E-11 2.02E-11 4.52E-11 67 23 1.37 27.49 4.69E-11 3.05E-11 2.24E-11 2.05E-11 4.69E-11 67 24 1.72 29.21 4.67E-11 2.95E-11 2.13E-11 1.86E-11 4.67E-11 3 25 1.44 30.66 4.51E-11 2.94E-11 2.30E-11 2.08E-11 4.51E-11 -73 26 1.68 32.34 4.78E-11 3.01E-11 2.22E-11 2.07E-11 4.78E-11 -73 27 1.24 33.58 4.93E-11 3.16E-11 2.34E-11 2.15E-11 4.93E-11 -71 28 1.65 35.24 4.86E-11 3.14E-11 2.22E-11 1.98E-11 4.86E-11 61 29 1.64 36.88 4.71E-11 3.14E-11 2.34E-11 2.13E-11 4.71E-11 -3 30 1.85 38.73 4.51E-11 3.01E-11 2.37E-11 2.17E-11 4.51E-11 65 31 1.91 40.64 4.84E-11 3.09E-11 2.23E-11 1.97E-11 4.84E-11 -73 32 1.95 42.59 4.80E-11 3.09E-11 2.30E-11 2.09E-11 4.80E-11 63 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-15 Table 6-7 Calculated Maximum Iron Atom Displacements at the Pressure Vessel Clad/Base Metal Interface Displacements (dpa)

Cycle Total Elevation Cycle Length Time 0° 15° 30° 45° Maximum of Max.

(EFPY) (EFPY)

(cm) 1 1.39 1.39 3.24E-03 1.95E-03 1.27E-03 1.11E-03 3.24E-03 -9 2 0.87 2.26 5.33E-03 3.26E-03 2.16E-03 1.87E-03 5.33E-03 -3 3 0.89 3.15 7.55E-03 4.63E-03 3.09E-03 2.69E-03 7.55E-03 -3 4 0.98 4.13 1.00E-02 6.16E-03 4.11E-03 3.56E-03 1.00E-02 -1 5 0.92 5.05 1.25E-02 7.65E-03 5.08E-03 4.43E-03 1.25E-02 -3 6 0.99 6.04 1.50E-02 9.16E-03 5.95E-03 5.24E-03 1.50E-02 -1 7 1.01 7.05 1.72E-02 1.07E-02 6.90E-03 6.15E-03 1.72E-02 -1 8 0.90 7.95 1.92E-02 1.18E-02 7.69E-03 6.83E-03 1.92E-02 -1 9 0.85 8.80 2.19E-02 1.34E-02 8.59E-03 7.67E-03 2.19E-02 -1 10 0.92 9.71 2.43E-02 1.49E-02 9.60E-03 8.54E-03 2.43E-02 -1 11 1.09 10.80 2.71E-02 1.66E-02 1.07E-02 9.59E-03 2.71E-02 -1 12 1.08 11.88 2.92E-02 1.80E-02 1.18E-02 1.06E-02 2.92E-02 -1 13 1.26 13.15 3.12E-02 1.93E-02 1.28E-02 1.15E-02 3.12E-02 3 14 1.33 14.47 3.31E-02 2.06E-02 1.38E-02 1.24E-02 3.31E-02 3 15 1.38 15.86 3.52E-02 2.19E-02 1.47E-02 1.33E-02 3.52E-02 3 16 1.38 17.24 3.72E-02 2.33E-02 1.59E-02 1.43E-02 3.72E-02 3 17 1.55 18.78 3.93E-02 2.49E-02 1.70E-02 1.52E-02 3.93E-02 3 18 1.48 20.27 4.12E-02 2.62E-02 1.80E-02 1.61E-02 4.12E-02 5 19 1.30 21.57 4.27E-02 2.74E-02 1.90E-02 1.70E-02 4.27E-02 5 20 1.56 23.13 4.50E-02 2.90E-02 2.02E-02 1.79E-02 4.50E-02 5 21 1.52 24.64 4.71E-02 3.05E-02 2.13E-02 1.88E-02 4.71E-02 5 22 1.48 26.12 4.92E-02 3.19E-02 2.24E-02 1.98E-02 4.92E-02 5 23 1.37 27.49 5.13E-02 3.33E-02 2.33E-02 2.07E-02 5.13E-02 5 24 1.72 29.21 5.38E-02 3.49E-02 2.45E-02 2.17E-02 5.38E-02 5 25 1.44 30.66 5.58E-02 3.62E-02 2.55E-02 2.26E-02 5.58E-02 5 26 1.68 32.34 5.84E-02 3.78E-02 2.67E-02 2.37E-02 5.84E-02 5 27 1.24 33.58 6.03E-02 3.90E-02 2.76E-02 2.45E-02 6.03E-02 5 28 1.65 35.24 6.28E-02 4.06E-02 2.88E-02 2.56E-02 6.28E-02 5 29 1.64 36.88 6.52E-02 4.23E-02 3.00E-02 2.67E-02 6.52E-02 5 30 1.85 38.73 6.79E-02 4.40E-02 3.13E-02 2.79E-02 6.79E-02 3 31 1.91 40.64 7.08E-02 4.59E-02 3.27E-02 2.91E-02 7.08E-02 3 32 1.95 42.59 7.37E-02 4.78E-02 3.41E-02 3.04E-02 7.37E-02 3 48 8.27E-02 5.35E-02 3.84E-02 3.43E-02 8.27E-02 3 51 8.76E-02 5.67E-02 4.08E-02 3.65E-02 8.76E-02 3 54 9.26E-02 5.99E-02 4.32E-02 3.86E-02 9.26E-02 3 60 1.02E-01 6.63E-02 4.79E-02 4.30E-02 1.02E-01 -1 Note(s):

1. Projections are based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-16 Table 6-8 Calculated Maximum Fast Neutron Fluence (E > 1.0 MeV) at Pressure Vessel Welds and Shells Fast Neutron (E > 1.0 MeV) Fluence (n/cm2)

Material 42.6 EFPY 48 EFPY 54 EFPY 60 EFPY Upper Shell Forging 2.63E+19 2.98E+19 3.37E+19 3.76E+19 Intermediate Shell Forging 4.50E+19 5.05E+19 5.66E+19 6.26E+19 Lower Shell Forging 4.43E+19 4.98E+19 5.58E+19 6.19E+19 Inlet Nozzle to Nozzle Shell Weld 2.64E+16 3.01E+16 3.42E+16 3.82E+16

- Lowest Extent Upper to Intermediate Shell Weld 2.82E+19 3.20E+19 3.61E+19 4.03E+19 Intermediate to Lower Shell Weld 4.43E+19 4.98E+19 5.58E+19 6.19E+19 Lower Shell to Lower Closure 1.52E+16 1.73E+16 1.95E+16 2.18E+16 Head Weld Note(s):

1. Projections are based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-17 Table 6-9 Calculated Maximum Iron Atom Displacements at Pressure Vessel Welds and Shells Iron Atom Displacements (dpa)

Material 42.6 EFPY 48 EFPY 54 EFPY 60 EFPY Upper Shell Forging 4.32E-02 4.90E-02 5.54E-02 6.17E-02 Intermediate Shell Forging 7.37E-02 8.27E-02 9.26E-02 1.03E-01 Lower Shell Forging 7.25E-02 8.14E-02 9.13E-02 1.01E-01 Inlet Nozzle to Nozzle Shell Weld 1.26E-04 1.43E-04 1.62E-04 1.80E-04

- Lowest Extent Upper to Intermediate Shell Weld 4.65E-02 5.26E-02 5.94E-02 6.62E-02 Intermediate to Lower Shell Weld 7.25E-02 8.14E-02 9.13E-02 1.01E-01 Lower Shell to Lower Closure 7.78E-05 8.82E-05 9.97E-05 1.11E-04 Head Weld Note:

1. Projections are based on Cycle 32 with a 10% bias on the peripheral and re-entrant corner assemblies.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 6-18 Table 6-10 Summary of Reactor Power and RCS Temperatures Core Core Inlet Core Power Average Coolant Cycle Temperature (MWth) Temperature

(°F)

(°F) 1 1650 571 536 2 1650 571 536 3 1650 571 536 4 1650 571 536 5 1650 571 536 6 1650 571 536 7 1650 571 536 8 1650 571 536 9 1650 571 536 10 1650 571 536 11 1650 571 536 12 1650 571 536 13 1650 571 536 14 1650 571 536 15 1650 571 536 16 1650 571 536 17 1650 571 536 18 1650 571 536 19 1650 571 536 20 1650 571 536 21 1650 571 536 22 1650 571 536 23 1650 563 531 24 1650 563 531 25 1650 562 530 26 1671(1) 563 530 27 1677 563 530 28 1677 562 531 29 1677 562 531 30 1677 562 531 31 1677 562 531 32 1677 562 531 Note(s):

1. There was a mid-cycle power uprate during Cycle 26 from 1650 MWth to 1677 MWth.

This uprate was done at a burnup of 4,975 MWD/MTU. The burnup-weighted average thermal power of 1671 MWth was used for the Cycle 26 transport calculations.

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Westinghouse Non-Proprietary Class 3 6-19 Figure 6-1 Prairie Island Unit 2 Plan View of the Reactor Geometry at the Core Midplane WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 6-20 Figure 6-2 Prairie Island Unit 2 Plan View of the Reactor Geometry at the Nozzle Centerline WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 6-21 Figure 6-3 Prairie Island Unit 2 Section View of the Reactor Geometry at 0-Degrees WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 6-22 Figure 6-4 Prairie Island Unit 2 Section View of the Reactor Geometry at 33-Degrees WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 7-1 7 SURVEILLANCE CAPSULE REMOVAL SCHEDULE The following surveillance capsule removal schedule (Table 7-1) meets the requirements of ASTM E185-82

[10] with consideration of NUREG-1801 [7] and NUREG-2191 [22]. It is noted that the Capsule N fluence bounds the projected fluence of the Prairie Island Unit 2 RV through 80 years of operation (peak vessel fluence of 7.46 x 1019 n/cm2 at 72 EFPY).

Table 7-1 Prairie Island Unit 2 Surveillance Capsule Withdrawal Schedule Fluence Capsule Capsule Location Lead Factor Withdrawal EFPY(1)

(n/cm2, E > 1.0 MeV) 1.39 V 77° 3.03 5.98E+18 (EOC 1) 4.13 T 67° 1.80 1.10E+19 (EOC 4) 8.80 R 257° 3.08 4.11E+19 (EOC 9) 17.24 P 247° 1.88 4.27E+19 (EOC 16) 40.64 N 237° 1.94 8.41E+19 (EOC 31)

S 57° --- Standby(2) ---

Notes:

1. Effective full-power years (EFPY) from plant startup. EOC = end-of-cycle.

2. It is recommended that Capsule S be removed at approximately 54 EFPY, which is the projected peak reactor vessel fluence at 120 years (1.11 x 1020 n/cm2 at 108 EFPY). The need for an alternative form of neutron dosimetry should be assessed when the last capsule is withdrawn.

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Westinghouse Non-Proprietary Class 3 8-1 8 REFERENCES

1. U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Regulatory Guide 1.99, Revision 2, Radiation Embrittlement of Reactor Vessel Materials, May 1988.

[Agencywide Documents Access and Management System (ADAMS) Accession Number ML003740284]

2. Westinghouse Report, WCAP-8193, Rev. 0, Northern States Power Co. Prairie Island Unit No. 2 Reactor Vessel Radiation Surveillance Program, September 1973.

3. ASTM E185-70, Standard Recommended Practice for Surveillance Tests for Nuclear Reactor Vessels, 1970.

4. Appendix G of the ASME Boiler and Pressure Vessel (B&PV) Code,Section XI, Division 1, Fracture Toughness Criteria for Protection Against Failure.

5. ASTM E208, Standard Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels, ASTM.

6. ASTM E399, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness Klc of Metallic Materials, ASTM.

7. NUREG-1801, Rev. 2, Generic Aging Lessons Learned (GALL) Report, December 2010, U.S.

Nuclear Regulatory Commission Report. [ADAMS Accession Number ML103490041]

8. Westinghouse Report RT-TR-22-26, Rev. 0, Prairie Island Unit 2 Surveillance Capsule Test Report, September 29, 2022.

9. 10 CFR 50, Appendix H, Reactor Vessel Material Surveillance Program Requirements, U.S.

Nuclear Regulatory Commission, Federal Register, October 2, 2020.

10. ASTM E185-82, Standard Practice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels, American Society for Testing and Materials, 1982.

11. ASTM E23-18, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials, 2018.

12. ASTM E2298-18, Standard Test Method for Instrumented Impact Testing of Metallic Materials, 2018.

13. ASTM A370-18, Standard Test Methods and Definitions for Mechanical Testing of Steel Products, 2018.

14. ASTM E8/E8M-16a, Standard Test Methods for Tension Testing of Metallic Materials, 2016.

15. ASTM E21-17, Standard Test Methods for Elevated Temperature Tension Tests of Metallic Materials, 2017.

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Westinghouse Non-Proprietary Class 3 8-2

16. Westinghouse Report, WCAP-14613, Rev. 2, Analysis of Capsule P from the Northern States Power Company Prairie Island Unit 2 Reactor Vessel Radiation Surveillance Program, February 1998.

17. ASTM E853-18, Standard Practice for Analysis and Interpretation of Light-Water Reactor Surveillance Neutron Exposure Results, 2018.

18. ASTM E693-94, Standard Practice for Characterizing Neutron Exposures in Iron and Low Alloy Steels in Terms of Displacements Per Atom (DPA), E706 (ID), 1994.

19. U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, Regulatory Guide 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence, March 2001. [ADAMS Accession Number ML010890301]

20. Westinghouse Report, WCAP-18124-NP-A, Rev. 0, Fluence Determination with RAPTOR-M3G and FERRET, July 2018. [ADAMS Accession Number ML18204A010]

21. Westinghouse Report, WCAP-18124-NP-A, Rev. 0, Supplement 1 NP-A, Fluence Determination with RAPTOR-M3G and FERRET - Supplement for Extended Beltline Materials, May 2022.

[ADAMS Accession Number ML22153A139]

22. NUREG-2191, Volume 2, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, July 2017, U.S. Nuclear Regulatory Commission Report. [ADAMS Accession Number ML17187A204]

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Westinghouse Non-Proprietary Class 3 A-1 APPENDIX A VALIDATION OF THE RADIATION TRANSPORT MODELS BASED ON NEUTRON DOSIMETRY MEASUREMENTS A.1 NEUTRON DOSIMETRY Comparisons of measured dosimetry results to both the calculated and least-squares adjusted values for Capsules V, T, R, P, and N are provided in this appendix. The sensor sets have been analyzed in accordance with the current dosimetry evaluation methodology described in Regulatory Guide 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence [A-1]. One of the main purposes for providing this material is to demonstrate that the overall measurements agree with the calculated and least-squares adjusted values to within 20% as specified by Regulatory Guide 1.190, thus serving to validate the calculated neutron exposures reported in Section 6.2.

A.1.1 Sensor Reaction Rate Determinations In this section, the results of the evaluations of Capsules V, T, R, P, and N are presented. The capsules designation, locations within the reactor, and time of withdrawal are as follows:

Azimuthal Withdrawal Irradiation Time Capsule Location Time (EFPY)

V 77º End of Cycle 1 1.39 T 67º End of Cycle 4 4.13 R 257º End of Cycle 9 8.80 P 247º End of Cycle 16 17.24 N 237º End of Cycle 31 40.64 S 57º Standby ---

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Westinghouse Non-Proprietary Class 3 A-2 The passive neutron sensors included in these evaluations are summarized as follows:

Sensor Material Reaction of Interest Capsule V Capsule T Capsule R Capsule P Capsule N Copper Cu-63 (n,) Co-60 X X X X X Iron Fe-54 (n,p) Mn-54 X X X X X Nickel Ni-58 (n,p) Co-58 X X X X X Uranium-238 U-238 (n,f) Cs-137 X X X X X Neptunium-237 Np-237 (n,f) Cs-137 X X X X X Cobalt-Aluminum(1) Co-59 (n,) Co-60 X X X X X Notes:

1. The cobalt-aluminum sensors include only bare sensors. For all the capsules withdrawn to-date, none of the cadmium shielded cobalt-aluminum wires have been recovered.

The design of the in-vessel surveillance capsules places the individual neutron sensors at several radial locations within the test specimen array. As a result of the various radial locations, gradient correction factors are applied to the measured reaction rates to index all of the neutron sensor measurements to a common geometric location (the center of the capsule) prior to use in the least-squares adjustment procedure. Pertinent physical and nuclear characteristics of the passive neutron sensors analyzed are listed in Table A-1.

The use of passive monitors does not yield a direct measure of the energy-dependent neutron exposure rate at the point of interest. Rather, the activation or fission process is a measure of the integrated effect that the time- and energy-dependent neutron exposure rate has on the target material over the course of the irradiation period. An accurate assessment of the average neutron exposure rate incident on the various monitors may be derived from the activation measurements only if the irradiation parameters are well known. In particular, the following variables are of interest:

• The measured specific activity of each monitor.

• The physical characteristics of each monitor.

• The operating history of the reactor.

• The energy response of each monitor.

• The neutron energy spectrum at the monitor location.

The radiometric counting of the sensors from Capsule N was carried out by Pace Analytical Services, Inc.

The radiometric counting followed established ASTM procedures. The previously withdrawn in-vessel Capsules V, T, R, and P were re-evaluated using the current calculational model.

The operating history of the reactor over the irradiation periods was based on the monthly power generation of Prairie Island Unit 2 from initial reactor criticality through the end of the dosimetry evaluation period.

For the sensor sets utilized in the surveillance capsules, the half-lives of the product isotopes are long enough that a monthly histogram describing reactor operation has proven to be an adequate representation for use in radioactive decay corrections for the reactions of interest in the exposure evaluations. The irradiation history for Cycle 1 through Cycle 16 is in [A-2]. The monthly thermal generation data for Cycle 17 through Cycle 31 were provided by Xcel Energy.

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Westinghouse Non-Proprietary Class 3 A-3 The irradiation history for Cycle 17 through Cycle 31 is summarized in Table A-2.

Having the measured specific activities, the physical characteristics of the sensors, and the operating history of the reactor, reaction rates referenced to full-power operation were determined from the following equation:

A R=

Pj N0 FY P Cj [1 etj ][etd,j ]

ref where:

R = Reaction rate averaged over the irradiation period and referenced to operation at a core power level of Pref (rps/nucleus).

A = Measured specific activity (dps/g).

N0 = Number of target element atoms per gram of sensor.

F = Atom fraction of the target isotope in the target element.

Y = Number of product atoms produced per reaction.

Pj = Average core power level during irradiation Period j (MW).

Pref = Maximum or reference power level of the reactor (MW).

Cj = Calculated ratio of (E > 1.0 MeV) during irradiation Period j to the time weighted average (E > 1.0 MeV) over the entire irradiation period.

= Decay constant of the product isotope (1/sec).

tj = Length of irradiation Period j (sec).

td,j = Decay time following irradiation Period j (sec).

The summation is carried out over the total number of monthly intervals comprising the irradiation period.

In the equation describing the reaction rate calculation, the Ratio [Pj]/[Pref] accounts for month-by-month variation of reactor core power level within any given fuel cycle as well as over multiple fuel cycles. The Ratio Cj, which was calculated for each fuel cycle using the transport methodology discussed in Section 6.2, accounts for the change in sensor reaction rates caused by variations in exposure rate level induced by changes in core spatial power distributions from fuel cycle to fuel cycle. For a single-cycle irradiation, Cj is normally taken to be 1.0. However, for multiple-cycle irradiations, the additional Cj term should be employed. The impact of changing exposure rate levels for constant power operation can be quite significant for sensor sets that have been irradiated for many cycles in a reactor that has transitioned from WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 A-4 non-low-leakage to low-leakage fuel management or for sensor sets contained in surveillance capsules that have been moved from one capsule location to another. The fuel-cycle-specific neutron exposure rate values are used to compute cycle-dependent values for Cj values at the radial and azimuthal center of the respective capsules at core midplane.

Prior to using the measured reaction rates in the least-squares evaluations of the dosimetry sensor sets, additional corrections were made to the U-238 measurements to account for the presence of 235U impurities in the sensors, as well as to adjust for the build-in of plutonium isotopes over the course of the irradiation.

Corrections were also made to the U-238 and Np-237 sensor reaction rates to account for gamma-ray-induced fission reactions that occurred over the course of the surveillance capsule irradiations. The correction factors corresponding to the Prairie Island Unit 2 fission sensor reaction rates are summarized as follows:

Correction Capsule V Capsule T Capsule R Capsule P Capsule N U-235 Impurity/Pu Build-in 0.8611 0.8417 0.7389 0.7332 0.6213 U-238 (,f) 0.9548 0.9596 0.9548 0.9603 0.9599 Net U-238 Correction 0.8222 0.8077 0.7055 0.7041 0.5964 Np-237 (,f) 0.9851 0.9855 0.9851 0.9856 0.9858 The correction factors were applied in a multiplicative fashion to the decay-corrected cadmium-covered fission sensor reaction rates.

Results of the sensor reaction rate determinations for the in-vessel Capsules V, T, R, P, and N are given in Table A-3 through Table A-7, where the measured specific activities, decay-corrected saturated specific activities, and computed reaction rates for each sensor are listed.

A.1.2 Least-Squares Evaluation of Sensor Sets Least-squares adjustment methods provide the capability of combining the measurement data with the corresponding neutron transport calculations resulting in a best-estimate neutron energy spectrum with associated uncertainties. Best-estimates for key exposure parameters such as fluence rate (E > 1.0 MeV) or dpa/s along with their uncertainties are then easily obtained from the adjusted spectrum. In general, the least-squares method, as applied to dosimetry evaluations, act to reconcile the measured sensor reaction rate data, dosimetry reaction cross-sections, and the calculated neutron energy spectrum within their respective uncertainties. For example, R i R i = ( ig ig )( g g )

g relates a set of measured reaction rates, Ri, to a single neutron spectrum, g, through the multigroup dosimeter reaction cross-sections, ig, each with an uncertainty . The primary objective of the least-squares evaluation is to produce unbiased estimates of the neutron exposure parameters at the location of the measurement.

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Westinghouse Non-Proprietary Class 3 A-5 For the least-squares evaluation of the Prairie Island Unit 2 dosimetry, the FERRET code [A-3] was employed to combine the results of the plant-specific neutron transport calculations and sensor set reaction rate measurements to determine the best-estimate values of exposure parameters (fluence rate (E > 1.0 MeV) and dpa) and their associated uncertainties.

The application of the least-squares methodology requires the following input:

1. The calculated neutron energy spectrum and associated uncertainties at the measurement location.

2. The measured reaction rates and associated uncertainty for each sensor contained in the multiple sensor set.

3. The energy-dependent dosimetry reaction cross-sections and associated uncertainties for each sensor contained in the multiple sensor set.

For the Prairie Island Unit 2, the calculated neutron spectrum was obtained from the results of plant-specific neutron transport calculations described in Section 6.2. The sensor reaction rates were derived from the measured specific activities using the procedures described in Section A.1.1. The dosimetry reaction cross-sections and uncertainties were obtained from the SNLRML dosimetry cross-section library [A-4].

The uncertainties associated with the measured reaction rates, dosimetry cross-sections, and calculated neutron spectrum were input to the least-squares procedure in the form of variances and covariances. The assignment of the input uncertainties followed the guidance provided in ASTM E944, Standard Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance [A-5].

The following provides a summary of the uncertainties associated with the least-squares evaluation of the Prairie Island Unit 2 surveillance capsule sensor sets.

Reaction Rate Uncertainties The overall uncertainty associated with the measured reaction rates includes components due to the basic measurement process, irradiation history corrections, and corrections for competing reactions. A high level of accuracy in the reaction rate determinations is ensured by utilizing laboratory procedures that conform to the ASTM National Consensus Standards for reaction rate determinations for each sensor type.

After combining all of these uncertainty components, the sensor reaction rates derived from the counting and data evaluation procedures were assigned the following net uncertainties for input to the least-squares evaluation:

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Westinghouse Non-Proprietary Class 3 A-6 Reaction Uncertainty (1) 63 Cu (n,) 60Co 5%

54 Fe (n,p) 54Mn 5%

58 Ni (n,p) 58Co 5%

59 Co (n,) 60Co 5%

238 U (n,f) FP 10%

237 Np (n,f) FP 10%

In the case of Capsule N, two sets of data are provided. The Case 1 data set was based on the use of the nominal uncertainties for the measured reaction rates. However, as seen in Table A-12, the value of 2 per degree of freedom associated with this evaluation was 1.128. A value of 2/DOF greater than 1.0 indicates that the uncertainties associated with the input parameters may have been underestimated. Since the same transport calculations and dosimetry reaction cross-sections were used in all five capsule evaluations with no issue arising with respect to capsules V, T, R, and P, it is not likely that the uncertainties associated with these input parameters caused the inconsistency noted in the Capsule N evaluation. Additionally, a comparison of the Capsule N normalized reaction rates with the database of 2-Loop Thermal Shield plant in-vessel capsules at 33 degrees was completed. This comparison showed that all normalized measured reaction rates fall within three standard deviations of the normalized reaction rates in the database. As such, they are all judged to be credible. Therefore, based on the assumption that the uncertainties associated with the Capsule N measured reaction rates were too small, the Case 2 least-squares analysis was performed using larger input uncertainties for the measured reaction rates. The reaction rate uncertainties used in the two least squares evaluations for Capsule N are summarized as follows:

Uncertainty (1)

Reaction Case 1 Case 2 63 Cu (n,) 60Co 5% 10%

54 Fe (n,p) 54Mn 5% 10%

58 Ni (n,p) 58Co 5% 10%

59 Co (n,) 60Co 5% 10%

238 U (n,f) FP 10% 15%

237 Np (n,f) FP 10% 15%

From Table A-13, it is noted that the used of the larger reaction rate uncertainties reduced the value of 2/DOF to 0.512. Therefore, for Capsule N, the Case 2 least squares evaluation was taken as the final result.

Dosimetry Cross-Section Uncertainties The reaction rate cross-sections used in the least-squares evaluations were taken from the SNLRML library.

This data library provides reaction cross-sections and associated uncertainties, including covariances, for WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 A-7 66 dosimetry sensors in common use. Both cross-sections and uncertainties are provided in a fine multigroup structure for use in least-squares adjustment applications. These cross-sections were compiled from recent cross-section evaluations, and they have been tested for accuracy and consistency for least-squares evaluations. Further, the library has been empirically tested for use in fission spectra determination, as well as in the fluence and energy characterization of 14 MeV neutron sources.

For sensors included in the Prairie Island Unit 2 surveillance program, the following uncertainties in the fission spectrum averaged cross-sections are provided in the SNLRML documentation package:

Reaction Uncertainty Cu-63 (n,) Co-60 4.08-4.16%

Fe-54 (n,p) Mn-54 3.05-3.11%

Ni-58 (n,p) Co-58 4.49-4.56%

Co-59 (n,) Co-60 0.79-3.59%

U-238 (n,f) 0.54-0.64%

Np-237 (n,f) 10.32-10.97%

These tabulated ranges provide an indication of the dosimetry cross-section uncertainties associated with the sensor sets used in LWR irradiations.

Calculated Neutron Spectrum The neutron spectra inputs to the least-squares adjustment procedure were obtained directly from the results of plant-specific transport calculations for each surveillance capsule irradiation period and location. The spectrum for each capsule was input in an absolute sense (rather than as simply a relative spectral shape).

Therefore, within the constraints of the assigned uncertainties, the calculated data were treated equally with the measurements.

While the uncertainties associated with the reaction rates were obtained from the measurement procedures and counting benchmarks and the dosimetry cross-section uncertainties were supplied directly with the SNLRML library, the uncertainty matrix for the calculated spectrum was constructed from the following relationship:

M gg' = R 2n + R g

• R g'

• Pgg' where Rn specifies an overall fractional normalization uncertainty and the fractional uncertainties Rg and Rg' specify additional random groupwise uncertainties that are correlated with a correlation matrix given by:

Pgg = [1 - ] gg + e-H WCAP-18795-NP December 2022 Revision 0

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Westinghouse Non-Proprietary Class 3 A-8 where:

(g g' ) 2 H=

2 2 The first term in the correlation matrix equation specifies purely random uncertainties, while the second term describes the short-range correlations over a group range ( specifies the strength of the latter term).

The value of is 1.0 when g = g, and is 0.0 otherwise.

The set of parameters defining the input covariance matrix for the Prairie Island Unit 2 calculated spectra was as follows:

Exposure Rate Normalization Uncertainty (Rn) 15%

Exposure Rate Group Uncertainties (Rg, Rg')

(E > 0.0055 MeV) 15%

(0.68 eV < E < 0.0055 MeV) 25%

(E < 0.68 eV) 50%

Short Range Correlation ()

(E > 0.0055 MeV) 0.9 (0.68 eV < E < 0.0055 MeV) 0.5 (E < 0.68 eV) 0.5 Exposure Rate Group Correlation Range ()

(E > 0.0055 MeV) 6 (0.68 eV < E < 0.0055 MeV) 3 (E < 0.68 eV) 2 A.1.3 Comparisons of Measurements and Calculations Results of the least-squares evaluations are provided in Table A-8 through Table A-13. In these tables, measured, calculated, and best-estimate values for sensor reaction rates are given. Also provided in these tabulations are ratios of the measured reaction rates to both the calculated and least-squares adjusted reaction rates. These ratios of measured-to-calculated (M/C) and measured-to-best estimate (M/BE) illustrate the consistency of the fit of the calculated neutron energy spectra to the measured reaction rates both before and after adjustment. Additionally, comparisons of the calculated and best-estimate values of neutron fluence rate (E > 1.0 MeV) and iron atom displacement rate are tabulated along with the best-estimate-to-calculated (BE/C) ratios observed for each of the capsules.

The data comparisons provided in Table A-8 through Table A-13 show that the adjustments to the calculated spectra are relatively small and within the assigned uncertainties for the calculated spectra, measured sensor reaction rates, and dosimetry reaction cross-sections. Further, these results indicate that the use of the least-squares evaluation results in a reduction in the uncertainties associated with the exposure of the surveillance capsules. From Section 6.4, the calculational uncertainty is specified as 13% at the 1 level.

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Westinghouse Non-Proprietary Class 3 A-9 Further comparisons of the measurement results with calculations are given in Table A-14 and Table A-15.

In Table A-14, calculations of individual threshold sensor reaction rates are compared directly with the corresponding measurements. These threshold reaction rate comparisons provide a good evaluation of the accuracy of the fast neutron portion of the calculated energy spectra. In Table A-15, calculations of fast neutron exposure rates in terms of fast neutron (E > 1.0 MeV) fluence rate and dpa/s are compared with the best-estimate results obtained from the least-squares evaluation of the capsule dosimetry results. These comparisons yield consistent and similar results with all measurement-to-calculation comparisons falling within the 20% limits specified as the acceptance criteria in Regulatory Guide 1.190.

In the case of the direct comparison of the measured and calculated sensor reaction rates, for the individual threshold sensors considered in the least-squares analysis, the M/C comparisons of the fast neutron threshold reactions range from 0.90 to 1.09. The overall average M/C ratio is 0.98 with an associated standard deviation of 9.8%.

In the case of the comparison of the best-estimate and calculated fast neutron exposure parameters, the BE/C comparisons are 0.97 and 0.98 for fast neutron (E > 1.0 MeV) fluence rate and iron atom displacement rate, respectively.

Based on these comparisons, it is concluded that the calculated fast neutron exposures provided in Section 6.2 are valid for use in the assessment of the condition of the materials comprising the beltline region of the Prairie Island Unit 2 reactor pressure vessel.

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Westinghouse Non-Proprietary Class 3 A-10 Table A-1 Nuclear Parameters Used in the Evaluation of Neutron Sensors 90%

Atomic Target Product Fission Reaction of Response Weight Atom Half-life Yield Interest Range(1)

(g/g-atom) Fraction (days) (%)

(MeV)

Cu-63 (n,) Co-60 63.546 0.6917 1925.28 - 4.53-11.0 Fe-54 (n,p) Mn-54 55.845 0.05845 312.13 - 2.27-7.54 Ni-58 (n,p) Co-58 58.693 0.68077 70.86 - 1.98-7.51 Co-59 (n,) Co-60 58.933 0.0015 1925.28 - Non-threshold U-238 (n,f) Cs-137 238.051 1.00 10975.76 6.02 1.44-6.69 Np-237 (n,f) Cs-137 237.048 1.00 10975.76 6.27 0.68-5.61 Note:

1. Energies between which 90% of activity is produced (U-235 fission spectrum) [A-6]

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Westinghouse Non-Proprietary Class 3 A-11 Table A-2 Monthly Thermal Generation at Prairie Island Unit 2 Cycles 17 through 31 Cycle 17 Cycle 18 Cycle 19 Cycle 20 Thermal Thermal Thermal Thermal Month Generation Month Generation Month Generation Month Generation

[MW-Hr] [MW-Hr] [MW-Hr] [MW-Hr]

6/27/1995 75988 3/30/1997 26012 1/1/1999 1069376 6/7/2000 854709 7/1/1995 1218591 4/1/1997 1040736 2/1/1999 1036346 7/1/2000 1230424 8/1/1995 1227600 5/1/1997 1191043 3/1/1999 1229905 8/1/2000 1230622 9/1/1995 1180266 6/1/1997 1191090 4/1/1999 1191542 9/1/2000 1184198 10/1/1995 1227600 7/1/1997 1196001 5/1/1999 1232232 10/1/2000 1231043 11/1/1995 1168654 8/1/1997 1231031 6/1/1999 1173590 11/1/2000 1191652 12/1/1995 1231175 9/1/1997 1190525 7/1/1999 1231528 12/1/2000 1229784 1/1/1996 1218525 10/1/1997 1230313 8/1/1999 1231668 1/1/2001 1225145 2/1/1996 1121189 11/1/1997 1191028 9/1/1999 1072708 2/1/2001 1106582 3/1/1996 1154299 12/1/1997 1231287 10/1/1999 1221341 3/1/2001 1222419 4/1/1996 1137599 1/1/1998 939213 11/1/1999 1188948 4/1/2001 1158990 5/1/1996 1229222 2/1/1998 0 12/1/1999 1217110 5/1/2001 354077 6/1/1996 1143478 3/1/1998 1056451 1/1/2000 1231319 6/1/2001 962014 7/1/1996 1103500 4/1/1998 1190681 2/1/2000 1152886 7/1/2001 1191567 8/1/1996 1219943 5/1/1998 1232133 3/1/2000 1230836 8/1/2001 1225305 9/1/1996 1191672 6/1/1998 1167691 4/1/2000 1098309 9/1/2001 1185794 10/1/1996 1207935 7/1/1998 1231407 5/1/2000 0 10/1/2001 1210389 11/1/1996 1188085 8/1/1998 1231786 11/1/2001 1059661 12/1/1996 1228990 9/1/1998 1148852 12/1/2001 1224856 1/1/1997 906076 10/1/1998 1230748 1/1/2002 1196794 2/1/1997 0 11/1/1998 317705 2/1/2002 28116 12/1/1998 0 Total 22380386 Total 21465733 Total 18809643 Total 22504141 EFPS 4.883E+07 EFPS 4.683E+07 EFPS 4.104E+07 EFPS 4.910E+07 EFPD 565.16 EFPD 542.06 EFPD 474.99 EFPD 568.29 EFPY 1.55 EFPY 1.48 EFPY 1.30 EFPY 1.56 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-12 Table A-2 Monthly Thermal Generation at Prairie Island Unit 2 Cycles 17 through 31 (cont.)

Cycle 21 Cycle 22 Cycle 23 Cycle 24 Thermal Thermal Thermal Thermal Month Generation Month Generation Month Generation Month Generation

[MW-Hr] [MW-Hr] [MW-Hr] [MW-Hr]

3/2/2002 1141963 10/10/2003 711673 6/11/2005 741210 12/15/2006 633256 4/1/2002 1166946 11/1/2003 1185786 7/1/2005 1224846 1/1/2007 1229041 5/1/2002 1225500 12/1/2003 1224823 8/1/2005 1224904 2/1/2007 1106467 6/1/2002 1185858 1/1/2004 1225381 9/1/2005 1184999 3/1/2007 846054 7/1/2002 1221635 2/1/2004 1146123 10/1/2005 1223543 4/1/2007 1043592 8/1/2002 1225458 3/1/2004 1225203 11/1/2005 1177296 5/1/2007 1227888 9/1/2002 1185913 4/1/2004 1155295 12/1/2005 1224848 6/1/2007 1187991 10/1/2002 1222094 5/1/2004 1225074 1/1/2006 1223916 7/1/2007 1227957 11/1/2002 1185952 6/1/2004 1185771 2/1/2006 487714 8/1/2007 1228169 12/1/2002 1225505 7/1/2004 1224369 3/1/2006 1224694 9/1/2007 1130705 1/1/2003 1206856 8/1/2004 1222124 4/1/2006 1176371 10/1/2007 1227781 2/1/2003 1106655 9/1/2004 1185565 5/1/2006 1228916 11/1/2007 1188861 3/1/2003 1224708 10/1/2004 1219475 6/1/2006 1189157 12/1/2007 1229147 4/1/2003 1165336 11/1/2004 1099413 7/1/2006 1188995 1/1/2008 1229835 5/1/2003 1225142 12/1/2004 1223666 8/1/2006 1228897 2/1/2008 1150644 6/1/2003 1185302 1/1/2005 1224633 9/1/2006 1165170 3/1/2008 1206182 7/1/2003 1224683 2/1/2005 1105536 10/1/2006 1216823 4/1/2008 1187368 8/1/2003 1207972 3/1/2005 1122097 11/1/2006 544083 5/1/2008 1226011 9/1/2003 407081 4/1/2005 471606 6/1/2008 1185834 5/1/2005 0 7/1/2008 1225203 8/1/2008 1224236 9/1/2008 727472 10/1/2008 0 Total 21940558 Total 21383613 Total 19876382 Total 24869695 EFPS 4.787E+07 EFPS 4.666E+07 EFPS 4.337E+07 EFPS 5.426E+07 EFPD 554.05 EFPD 539.99 EFPD 501.93 EFPD 628.02 EFPY 1.52 EFPY 1.48 EFPY 1.37 EFPY 1.72 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-13 Table A-2 Monthly Thermal Generation at Prairie Island Unit 2 Cycles 17 through 31 (cont.)

Cycle 25 Cycle 26 Cycle 27 Cycle 28 Thermal Thermal Thermal Thermal Month Generation Month Generation Month Generation Month Generation

[MW-Hr] [MW-Hr] [MW-Hr] [MW-Hr]

11/1/2008 1043453 5/26/2010 181340 5/29/2012 32064 1/3/2014 973614 12/1/2008 1228706 6/1/2010 1183890 6/1/2012 1174547 2/1/2014 1128408 1/1/2009 1228724 7/1/2010 1226471 7/1/2012 1247728 3/1/2014 1236797 2/1/2009 1109454 8/1/2010 1226649 8/1/2012 1246540 4/1/2014 1207937 3/1/2009 1229385 9/1/2010 1183241 9/1/2012 1206440 5/1/2014 1001225 4/1/2009 1189241 10/1/2010 1227610 10/1/2012 1207071 6/1/2014 1203966 5/1/2009 1206648 11/1/2010 1206766 11/1/2012 1207742 7/1/2014 1247880 6/1/2009 1188775 12/1/2010 1246099 12/1/2012 1247012 8/1/2014 1247821 7/1/2009 1223052 1/1/2011 1246011 1/1/2013 1211658 9/1/2014 1205353 8/1/2009 1222790 2/1/2011 1126465 2/1/2013 1127094 10/1/2014 1083893 9/1/2009 1184118 3/1/2011 1247370 3/1/2013 1247860 11/1/2014 1207978 10/1/2009 1227379 4/1/2011 1202166 4/1/2013 1207453 12/1/2014 1247969 11/1/2009 1185142 5/1/2011 1181954 5/1/2013 1198727 1/1/2015 1248353 12/1/2009 1226266 6/1/2011 1203939 6/1/2013 1033796 2/1/2015 1127999 1/1/2010 1225975 7/1/2011 1244062 7/1/2013 1007918 3/1/2015 342250 2/1/2010 1110106 8/1/2011 1245244 8/1/2013 1008484 4/1/2015 1103690 3/1/2010 1229268 9/1/2011 1206628 9/1/2013 642402 5/1/2015 1233108 4/1/2010 602761 10/1/2011 585661 10/1/2013 0 6/1/2015 937272 11/1/2011 1207636 11/1/2013 0 7/1/2015 1247623 12/1/2011 1248018 12/1/2013 0 8/1/2015 1247039 1/1/2012 1248637 9/1/2015 1209080 2/1/2012 781320 10/1/2015 638708 3/1/2012 0 11/1/2015 0 4/1/2012 0 Total 20861244 Total 24657176 Total 18254534 Total 24327965 EFPS 4.552E+07 EFPS 5.312E+07 EFPS 3.919E+07 EFPS 5.222E+07 EFPD 526.80 EFPD 614.81 EFPD 453.55 EFPD 604.45 EFPY 1.44 EFPY 1.68 EFPY 1.24 EFPY 1.65 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-14 Table A-2 Monthly Thermal Generation at Prairie Island Unit 2 Cycles 17 through 31 (cont.)

Cycle 29 Cycle 30 Cycle 31 Thermal Thermal Thermal Month Generation Month Generation Month Generation

[MW-Hr] [MW-Hr] [MW-Hr]

12/5/2015 310537 11/21/2017 353040 10/28/2019 92447 1/1/2016 0 12/1/2017 1251387 11/1/2019 1211100 2/1/2016 211718 1/1/2018 1251004 12/1/2019 1251473 3/1/2016 1249663 2/1/2018 1130125 1/1/2020 1251331 4/1/2016 1209451 3/1/2018 1251040 2/1/2020 1169142 5/1/2016 1250183 4/1/2018 1206955 3/1/2020 1249699 6/1/2016 1208231 5/1/2018 1250965 4/1/2020 1208979 7/1/2016 1247211 6/1/2018 1210003 5/1/2020 1237156 8/1/2016 1247986 7/1/2018 1251370 6/1/2020 1183794 9/1/2016 1204150 8/1/2018 1251177 7/1/2020 1250514 10/1/2016 1247704 9/1/2018 1210055 8/1/2020 1250946 11/1/2016 1207974 10/1/2018 1251124 9/1/2020 1120784 12/1/2016 1249217 11/1/2018 1207350 10/1/2020 1252048 1/1/2017 1182008 12/1/2018 1250374 11/1/2020 1205131 2/1/2017 1130755 1/1/2019 1252476 12/1/2020 1252794 3/1/2017 1250940 2/1/2019 1131344 1/1/2021 1253136 4/1/2017 1147542 3/1/2019 1252656 2/1/2021 1131808 5/1/2017 1252118 4/1/2019 1211916 3/1/2021 1250685 6/1/2017 1211399 5/1/2019 1247839 4/1/2021 1212547 7/1/2017 1251833 6/1/2019 1211475 5/1/2021 1252614 8/1/2017 1250924 7/1/2019 1251166 6/1/2021 1211746 9/1/2017 1124021 8/1/2019 1237465 7/1/2021 1251771 10/1/2017 517064 9/1/2019 1009021 8/1/2021 1239063 10/1/2019 109665 9/1/2021 1015179 10/1/2021 11128 Total 24162628 Total 27240994 Total 28017016 EFPS 5.187E+07 EFPS 5.848E+07 EFPS 6.014E+07 EFPD 600.34 EFPD 676.83 EFPD 696.11 EFPY 1.64 EFPY 1.85 EFPY 1.91 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-15 Table A-3 Measured Sensor Activities and Reaction Rates for Surveillance Capsule V Corrected Average Average Measured Saturated Reaction Reaction Reaction Target Activity Activity Rate Rate Rate Sample Isotope (dps/g) (dps/g) (rps/atom) (rps/atom) (rps/atom)77-918 Cu-63 5.900E+04 4.320E+05 6.591E-17 77-919 Cu-63 6.460E+04 4.730E+05 7.216E-17 6.903E-17 6.903E-17 77-921 Fe-54 2.370E+06 5.045E+06 8.004E-15 77-922 Fe-54 2.210E+06 4.704E+06 7.464E-15 77-923 Fe-54 2.340E+06 4.981E+06 7.903E-15 77-924 Fe-54 2.430E+06 5.173E+06 8.207E-15 77-925 Fe-54 2.490E+06 5.300E+06 8.409E-15 7.997E-15 7.997E-15 77-920 Ni-58 1.397E+07 7.543E+07 1.080E-14 1.080E-14 1.080E-14 77-926 U-238 (Cd) 2.620E+05 8.394E+06 5.512E-14 5.512E-14 4.532E-14 77-927 Np-237 (Cd) 2.250E+06 7.209E+07 4.526E-13 4.526E-13 4.459E-13 77-914 Co-59 2.150E+07 1.277E+08 8.334E-12 77-916 Co-59 2.020E+07 1.200E+08 7.830E-12 8.082E-12 8.082E-12 Note(s):

1. Measured activity is decay corrected to 3/14/1977.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-16 Table A-4 Measured Sensor Activities and Reaction Rates for Surveillance Capsule T Corrected Average Average Measured Saturated Reaction Reaction Reaction Target Activity Activity Rate Rate Rate Sample Isotope (dps/g) (dps/g) (rps/atom) (rps/atom) (rps/atom) 80-2999 Cu-63 1.040E+05 3.315E+05 5.058E-17 80-2003 Cu-63 1.160E+05 3.698E+05 5.641E-17 5.350E-17 5.350E-17 80-2997 Fe-54 1.650E+06 3.647E+06 5.786E-15 80-2998 Fe-54 1.470E+06 3.249E+06 5.155E-15 80-3000 Fe-54 1.650E+06 3.647E+06 5.786E-15 80-3002 Fe-54 1.610E+06 3.559E+06 5.646E-15 80-3006 Fe-54 1.720E+06 3.802E+06 6.032E-15 5.681E-15 5.681E-15 80-3001 Ni-58 1.790E+06 5.732E+07 8.206E-15 8.206E-15 8.206E-15 80-3007 U-238 (Cd) 4.840E+05 5.471E+06 3.592E-14 3.592E-14 2.901E-14 80-3008 Np-237 (Cd) 4.090E+06 4.623E+07 2.902E-13 2.902E-13 2.860E-13 80-2995 Co-59 2.650E+07 6.682E+07 4.360E-12 80-3004 Co-59 2.600E+07 6.556E+07 4.277E-12 4.319E-12 4.319E-12 Note(s):

1. Measured activity is decay corrected to 12/2/1980.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-17 Table A-5 Measured Sensor Activities and Reaction Rates for Surveillance Capsule R Corrected Average Average Measured Saturated Reaction Reaction Reaction Target Activity Activity Rate Rate Rate Sample Isotope (dps/g) (dps/g) (rps/atom) (rps/atom) (rps/atom) 86-2035 Cu-63 2.380E+05 4.768E+05 7.274E-17 86-2037 Cu-63 2.560E+05 5.129E+05 7.824E-17 7.549E-17 7.549E-17 86-2028 Fe-54 2.642E+06 5.404E+06 8.574E-15 86-2036 Fe-54 2.431E+06 4.973E+06 7.889E-15 86-2030 Fe-54 2.602E+06 5.322E+06 8.444E-15 86-2038 Fe-54 2.525E+06 5.165E+06 8.194E-15 86-2032 Fe-54 2.851E+06 5.832E+06 9.252E-15 86-2033 Fe-54 2.789E+06 5.705E+06 9.051E-15 8.567E-15 8.567E-15 86-2031 Ni-58 3.320E+06 8.237E+07 1.179E-14 1.179E-14 1.179E-14 86-2025 U-238 (Cd) 2.165E+06 1.222E+07 8.025E-14 8.025E-14 5.661E-14 86-2026 Np-237 (Cd) 1.282E+07 7.237E+07 4.543E-13 4.543E-13 4.475E-13 86-2029 Co-59 6.924E+07 1.126E+08 7.343E-12 86-2034 Co-59 7.604E+07 1.236E+08 8.064E-12 7.703E-12 7.703E-12 Note(s):

1. Measured activity is decay corrected to 7/22/1986.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-18 Table A-6 Measured Sensor Activities and Reaction Rates for Surveillance Capsule P Corrected Average Average Measured Saturated Reaction Reaction Reaction Target Activity Activity Rate Rate Rate Sample Isotope (dps/g) (dps/g) (rps/atom) (rps/atom) (rps/atom) 95-2274 Cu-63 1.980E+05 3.226E+05 4.921E-17 95-2278 Cu-63 2.140E+05 3.487E+05 5.319E-17 5.120E-17 5.120E-17 95-2273 Fe-54 1.930E+06 3.312E+06 5.254E-15 95-2275 Fe-54 1.650E+06 2.831E+06 4.492E-15 95-2277 Fe-54 1.850E+06 3.174E+06 5.036E-15 95-2279 Fe-54 1.780E+06 3.054E+06 4.846E-15 95-2282 Fe-54 2.070E+06 3.552E+06 5.635E-15 5.053E-15 5.053E-15 95-2276 Ni-58 7.830E+06 4.984E+07 7.135E-15 7.135E-15 7.135E-15 95-2269 U-238 (Cd) 1.690E+06 5.421E+06 3.560E-14 3.560E-14 2.507E-14 95-2270 Np-237 (Cd) 1.160E+07 3.721E+07 2.336E-13 2.336E-13 2.302E-13 95-2271 Co-59 3.930E+07 5.065E+07 3.304E-12 95-2280 Co-59 4.030E+07 5.193E+07 3.388E-12 3.346E-12 3.346E-12 Note(s):

1. Measured activity is decay corrected to 10/20/1995.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-19 Table A-7 Measured Sensor Activities and Reaction Rates for Surveillance Capsule N Corrected Average Average Measured Saturated Reaction Reaction Reaction Target Activity Activity Rate Rate Rate Sample Isotope (dps/g) (dps/g) (rps/atom) (rps/atom) (rps/atom) 30490505006 Cu-63 1.420E+05 2.202E+05 3.360E-17 30490505009 Cu-63 1.510E+05 2.342E+05 3.572E-17 3.466E-17 3.466E-17 30490505004 Fe-54 1.320E+06 2.410E+06 3.823E-15 30490505005 Fe-54 1.150E+06 2.099E+06 3.331E-15 30490505008 Fe-54 1.220E+06 2.227E+06 3.533E-15 30490505010 Fe-54 1.210E+06 2.209E+06 3.505E-15 30490505011 Fe-54 1.240E+06 2.264E+06 3.591E-15 3.557E-15 3.557E-15 30490505007 Ni-58 3.430E+06 4.385E+07 6.279E-15 6.279E-15 6.279E-15 30490505001 U-238 (Cd) 3.130E+06 5.685E+06 3.733E-14 3.733E-14 2.226E-14 30490505002 Np-237 (Cd) 1.650E+07 2.997E+07 1.881E-13 1.881E-13 1.854E-13 30490505003 Co-59 3.780E+07 4.632E+07 3.022E-12 3.022E-12 3.022E-12 Note(s):

1. Measured activity is decay corrected to 5/15/2022.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-20 Table A-8 Least-Squares Evaluation of Dosimetry in Surveillance Capsule V (13° Position, Core Midplane, Irradiated During Cycle 1) 2/DOF = 0.199 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 6.90E-17 7.02E-17 6.78E-17 0.98 1.02 0.97 54 Fe (n,p) 54Mn 8.00E-15 8.47E-15 8.06E-15 0.94 0.99 0.95 58 58 Ni (n,p) Co 1.08E-14 1.18E-14 1.12E-14 0.91 0.97 0.94 238 U(Cd) (n,f) 137Cs 4.53E-14 4.50E-14 4.36E-14 1.01 1.04 0.97 237 137 Np(Cd) (n,f) Cs 4.46E-13 3.95E-13 4.18E-13 1.13 1.06 1.06 59 60 Co (n,) Co 8.08E-12 1.01E-11 8.13E-12 0.80 0.99 0.80 Average of Fast Energy Threshold Reactions 0.99 1.02 0.98 Percent Standard Deviation 8.6 3.6 4.9 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 1.37E+11 13 1.34E+11 6 0.98 (n/cm2-s)

Displacement Rate 2.46E-10 13 2.44E-10 7 0.99 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-21 Table A-9 Least-Squares Evaluation of Dosimetry in Surveillance Capsule T (23° Position, Core Midplane, Irradiated During Cycles 1 through 4) 2/DOF = 0.176 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 5.35E-17 5.62E-17 5.34E-17 0.95 1.00 0.95 54 Fe (n,p) 54Mn 5.68E-15 6.04E-15 5.83E-15 0.94 0.97 0.96 58 58 Ni (n,p) Co 8.21E-15 8.30E-15 8.14E-15 0.99 1.01 0.98 238 U(Cd) (n,f) 137Cs 2.90E-14 2.93E-14 2.93E-14 0.99 0.99 1.00 237 137 Np(Cd) (n,f) Cs 2.86E-13 2.34E-13 2.63E-13 1.22 1.09 1.12 59 60 Co (n,) Co 4.32E-12 5.16E-12 4.34E-12 0.84 1.00 0.84 Average of Fast Energy Threshold Reactions 1.02 1.01 1.00 Percent Standard Deviation 11.3 4.5 6.9 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 8.49E+10 13 8.68E+10 6 1.02 (n/cm2-s)

Displacement Rate 1.46E-10 13 1.51E-10 7 1.03 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-22 Table A-10 Least-Squares Evaluation of Dosimetry in Surveillance Capsule R (13° Position, Core Midplane, Irradiated During Cycles 1 through 9) 2/DOF = 0.684 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 7.55E-17 7.62E-17 7.39E-17 0.99 1.02 0.97 54 Fe (n,p) 54Mn 8.57E-15 9.19E-15 8.80E-15 0.93 0.97 0.96 58 58 Ni (n,p) Co 1.18E-14 1.28E-14 1.22E-14 0.92 0.96 0.95 238 U(Cd) (n,f) 137Cs 5.66E-14 4.89E-14 4.82E-14 1.16 1.18 0.99 237 137 Np(Cd) (n,f) Cs 4.47E-13 4.30E-13 4.39E-13 1.04 1.02 1.02 59 60 Co (n,) Co 7.70E-12 1.10E-11 7.78E-12 0.70 0.99 0.71 Average of Fast Energy Threshold Reactions 1.01 1.03 0.98 Percent Standard Deviation 9.7 8.6 2.8 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 1.48E+11 13 1.48E+11 6 1.00 (n/cm2-s)

Displacement Rate 2.67E-10 13 2.67E-10 7 1.00 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-23 Table A-11 Least-Squares Evaluation of Dosimetry in Surveillance Capsule P (33° Position, Core Midplane, Irradiated During Cycles 1 through 16) 2/DOF = 0.139 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 5.12E-17 5.36E-17 5.03E-17 0.96 1.02 0.94 54 Fe (n,p) 54Mn 5.05E-15 5.68E-15 5.18E-15 0.89 0.97 0.91 58 58 Ni (n,p) Co 7.13E-15 7.79E-15 7.16E-15 0.92 1.00 0.92 238 U(Cd) (n,f) 137Cs 2.51E-14 2.73E-14 2.53E-14 0.92 0.99 0.93 237 137 Np(Cd) (n,f) Cs 2.30E-13 2.17E-13 2.17E-13 1.06 1.06 1.00 59 60 Co (n,) Co 3.35E-12 4.73E-12 3.38E-12 0.71 0.99 0.71 Average of Fast Energy Threshold Reactions 0.95 1.01 0.94 Percent Standard Deviation 7.0 3.4 3.8 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 7.88E+10 13 7.37E+10 6 0.93 (n/cm2-s)

Displacement Rate 1.35E-10 13 1.28E-10 7 0.95 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-24 Table A-12 Least-Squares Evaluation of Dosimetry in Surveillance Capsule N (33° Position, Core Midplane, Irradiated During Cycles 1 through 31) - Case 1 2/DOF = 1.128 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 3.47E-17 4.23E-17 3.52E-17 0.82 0.98 0.83 54 Fe (n,p) 54Mn 3.56E-15 4.57E-15 3.92E-15 0.78 0.91 0.86 58 58 Ni (n,p) Co 6.28E-15 6.30E-15 5.80E-15 1.00 1.09 0.92 238 U(Cd) (n,f) 137Cs 2.23E-14 2.25E-14 2.09E-14 0.99 1.06 0.93 237 137 Np(Cd) (n,f) Cs 1.85E-13 1.82E-13 1.81E-13 1.02 1.02 0.99 59 60 Co (n,) Co 3.02E-12 3.98E-12 3.04E-12 0.76 0.99 0.76 Average of Fast Energy Threshold Reactions 0.92 1.01 0.91 Percent Standard Deviation 12.2 7.0 6.9 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 6.57E+10 13 6.27E+10 6 0.95 (n/cm2-s)

Displacement Rate 1.13E-10 13 1.09E-10 7 0.96 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-25 Table A-13 Least-Squares Evaluation of Dosimetry in Surveillance Capsule N (33° Position, Core Midplane, Irradiated During Cycles 1 through 31) - Case 2 2/DOF = 0.512 Reaction Rate (rps/atom)

Best-Measured Calculated Estimate Reaction (M) (C) (BE) M/C M/BE BE/C 63 Cu (n,) 60Co 3.47E-17 4.23E-17 3.64E-17 0.82 0.95 0.86 54 Fe (n,p) 54Mn 3.56E-15 4.57E-15 4.04E-15 0.78 0.88 0.88 58 58 Ni (n,p) Co 6.28E-15 6.30E-15 5.71E-15 1.00 1.10 0.91 238 U(Cd) (n,f) 137Cs 2.23E-14 2.25E-14 2.07E-14 0.99 1.08 0.92 237 137 Np(Cd) (n,f) Cs 1.85E-13 1.82E-13 1.76E-13 1.02 1.05 0.97 59 60 Co (n,) Co 3.02E-12 3.98E-12 3.09E-12 0.76 0.98 0.78 Average of Fast Energy Threshold Reactions 0.92 1.01 0.91 Percent Standard Deviation 12.2 9.3 4.6 Best-Calculated Estimate Integral Quantity (C)  % Unc. (BE)  % Unc. BE/C Neutron Fluence Rate (E > 1.0 MeV) 6.57E+10 13 6.16E+10 7 0.94 (n/cm2-s)

Displacement Rate 1.13E-10 13 1.07E-10 8 0.94 (dpa/s)

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-26 Table A-14 Measured-to-Calculated (M/C) Reaction Rates - In-Vessel Capsules Capsule  % Std.

Reaction V T R P N Average Dev.

63 60 Cu (n,) Co 0.98 0.95 0.99 0.96 0.82 0.94 7.3 54 Fe (n,p) 54Mn 0.94 0.94 0.93 0.89 0.78 0.90 7.6 58 Ni (n,p) 58Co 0.91 0.99 0.92 0.92 1.00 0.95 4.6 238 U(Cd) (n,f) 137Cs 1.01 0.99 1.16 0.92 0.99 1.01 8.7 237 Np(Cd) (n,f) 137Cs 1.13 1.22 1.04 1.06 1.02 1.09 7.5 Average of M/C Results 0.98 9.8 Table A-15 Best-Estimate-to-Calculated (BE/C) Exposure Rates - In-Vessel Capsules Neutron Fluence (E > 1.0 MeV)

Rate Iron Atom Displacement Rate Capsule BE/C BE/C V 0.98 0.99 T 1.02 1.03 R 1.00 1.00 P 0.93 0.95 N 0.94 0.94 Average 0.97 0.98

% Std. Dev. 3.9 3.8 WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 A-27 A.2 REFERENCES A-1 U.S. Nuclear Regulatory Commission Regulatory Guide 1.190, Calculational and Dosimetry Methods for Determining Pressure Vessel Neutron Fluence, March 2001. [ADAMS Accession Number ML010890301]

A-2 Westinghouse Report, WCAP-14613, Rev. 2, Analysis of Capsule P from the Northern States Power Company Prairie Island Unit 2 Reactor Vessel Radiation Surveillance Program, February 1998.

A-3 A. Schmittroth, FERRET Data Analysis Core, HEDL-TME 79-40, Hanford Engineering Development Laboratory, Richland, WA, September 1979.

A-4 RSICC Data Library Collection DLC-178, SNLRML Recommended Dosimetry Cross-Section Compendium, July 1994.

A-5 ASTM Standard E944-19, Standard Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance, 2019.

A-6 ASTM Standard E844-18, Standard Guide for Sensor Set Design and Irradiation for Reactor Surveillance, 2018.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-1 APPENDIX B LOAD-TIME RECORDS FOR CHARPY SPECIMEN TESTS FROM CAPSULE N

• NLXX denotes Lower Shell Forging D (Heat # 22642), Tangential Orientation

• NTXX denotes Lower Shell Forging D (Heat # 22642), Axial Orientation

• NWXX denotes Surveillance Weld material

• NHXX denotes Heat-Affected Zone (HAZ) material

• RXX denotes Correlation Monitor material Note that the instrumented Charpy data is not required per ASTM Standards E185-82 or E23-18.

WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-2 NL59: Tested at 73°F NL56: Tested at 120°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-3 NL53: Tested at 130°F NL57: Tested at 140°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-4 NL51: Tested at 155°F NL49: Tested at 165°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-5 NL58: Tested at 175°F NL55: Tested at 200°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-6 NL60: Tested at 225°F NL52: Tested at 250°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-7 NL54: Tested at 300°F NL50: Tested at 325°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-8 NT54: Tested at 100°F NT56: Tested at 120°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-9 NT49: Tested at 140°F NT59: Tested at 155°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-10 NT58: Tested at 165°F NT53: Tested at 170°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-11 NT60: Tested at 175°F NT57: Tested at 200°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-12 NT55: Tested at 225°F NT51: Tested at 275°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-13 NT50: Tested at 300°F NT52: Tested at 325°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-14 NW36: Tested at 30°F NW39: Tested at 50°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-15 NW38: Tested at 73°F NW40: Tested at 100°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-16 NW37: Tested at 175°F NW35: Tested at 225°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-17 NW33: Tested at 275°F NW34: Tested at 300°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-18 NH39: Tested at -25°F NH33: Tested at 25°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-19 NH36: Tested at 30°F NH40: Tested at 60°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-20 NH37: Tested at 90°F NH34: Tested at 120°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-21 NH35: Tested at 175°F NH38: Tested at 275°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-22 R37: Tested at 200°F R35: Tested at 225°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-23 R34: Tested at 240°F R33: Tested at 275°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-24 R36: Tested at 320°F R38: Tested at 375°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)

Westinghouse Non-Proprietary Class 3 B-25 R39: Tested at 425°F R40: Tested at 450°F WCAP-18795-NP December 2022 Revision 0

• • • This record was final approved on 12/14/2022, 8:08:16 AM. (This statement was added by the PRIME system upon its validation)