ML15134A125

NRR E-mail Capture - FW: Raptor Slides

ML15134A125
Person / Time
Site:	Catawba
Issue date:	05/14/2015
From:	Ed Miller Plant Licensing Branch II
To:	Matthew Hardgrove Office of Nuclear Reactor Regulation
References
Download: ML15134A125 (27)

Text

NRR-PMDAPEm Resource From: Miller, Ed Sent: Thursday, May 14, 2015 8:26 AM To: Hardgrove, Matthew; Jenkins, Joel; Jackson, Christopher; Pascarelli, Robert; Poehler, Jeffrey

Subject:

FW: RAPTOR slides Attachments: Duke Final slides for NRC RAPTOR presentation dated 5-12-15 rev 1.pdf; Catawba Unit 1 MUR RAI Whitepaper Slides_prop3_NRC.pdf These are updated slides from Duke for the 5/19 meeting. The licensee indicated the change was on slide 6.

Ed 1

Hearing Identifier: NRR_PMDA Email Number: 2067 Mail Envelope Properties (9C2386A0C0BC584684916F7A0482B6CA018F6CB564AC)

Subject:

FW: RAPTOR slides Sent Date: 5/14/2015 8:26:11 AM Received Date: 5/14/2015 8:26:00 AM From: Miller, Ed Created By: Ed.Miller@nrc.gov Recipients:

"Hardgrove, Matthew" <Matthew.Hardgrove@nrc.gov>

Tracking Status:: Response: None : 4/29/2015 4:26:00 PM "Jenkins, Joel" <Joel.Jenkins@nrc.gov>

Tracking Status:: Response: None : 4/30/2015 6:58:00 AM "Jackson, Christopher" <Christopher.Jackson@nrc.gov>

Tracking Status:: Response: None : 5/5/2015 2:16:00 PM "Pascarelli, Robert" <Robert.Pascarelli@nrc.gov>

Tracking Status:: Response: None : 4/29/2015 4:54:00 PM "Poehler, Jeffrey" <Jeffrey.Poehler@nrc.gov>

Tracking Status:: Response: None : 5/1/2015 9:32:00 AM Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 122 5/14/2015 8:26:00 AM Duke Final slides for NRC RAPTOR presentation dated 5-12-15 rev 1.pdf 117259 Catawba Unit 1 MUR RAI Whitepaper Slides_prop3_NRC.pdf 634311 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

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Westinghouse Non-Proprietary Class 3 © 2015 Westinghouse Electric Company LLC. All Rights Reserved.

Catawba Unit 1 MUR SRXB-RAI 8 Response Jianwei Chen Principal Engineer, Ph. D Greg A. Fischer Principal Engineer, P.E.

1

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Background

• The neutron fluence exposure at reactor pressure vessel (RPV) is an important input to the reactor vessel integrity (RVI) assessment, which is a critical evaluation for power uprate and plant life extension

• Traditionally, the neutron fluence has been evaluated using discrete ordinates radiation transport codes:

- TWOTRAN (1968) - Can only solve 1-D and 2-D problems

- DOT (1970) - Can only solve 1-D and 2-D problems

- DORT (1980s) - Can only solve 1-D and 2-D problems

- TORT - Can solve 3-D problems, but not for full-size commercial reactor vessels per Regulatory Guide 1.190 pedigree due to computer resource limitations 2

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Background

• RAPTOR-M3G was developed to overcome TORTs limitations Feature TORT RAPTOR-M3G Solves the linear Boltzmann radiation transport equation in 3D Applies the method of discrete ordinates (the SN method) to treat directional variables Applies weighted finite-difference methods to treat spatial variables Applies a multigroup formulation to treat energy dependence DOORS Package (DORT/TORT) input format Execute on a one-workstation platform Executes simultaneously in-parallel on a network of workstations Execute with theta-weighted (TW) spatial differencing scheme Execute with directional theta-weighted (DTW) spatial differencing scheme 3

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Background

• Westinghouse has performed the neutron fluence evaluation in support of the Catawba Unit 1 MUR using RAPTOR-M3G in WCAP-17669-NP, Revision 0

• NRC issued SRXB-RAI 8:

- The RAPTOR-M3G code used to calculate fluence for MUR conditions does not appear to be approved by the NRC for use in this scenario. The NRC staff requests that the licensee provide justification for the use of RAPTOR-M3G for fluence calculations for MUR conditions, or provide an alternative fluence calculation using an NRC approved method.

4

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Westinghouse RAI Response

• Westinghouse/Duke are providing justification to the NRC that the use of RAPTOR-M3G for fluence calculations for MUR conditions is acceptable.

• Additional Catawba Unit 1 specific benchmark calculations have been done between TORT and RAPTOR-M3G

- For limiting RPV materials

- For representative fuel cycles

• Due to computer limitations with TORT, three reduced size models were used:

- Upper Reactor Environment (URE) model (Weld 06)

- Midplane Reactor Environment (MRE) model (Weld 05)

- Lower Reactor Environment (LRE) model (Weld 04) 5

Westinghouse Non-Proprietary Class 3 © 2015 Westinghouse Electric Company LLC. All Rights Reserved.

Westinghouse RAI Response Strategy 4 sets of results for detailed comparison of TORT and RAPTOR-M3G runs 6

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Questions?

7

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Westinghouse RAI Response Calculations

• RPV Materials Evaluated in Benchmark Calculations

- Upper Shell to Intermediate Shell Circumferential Weld W06

- Intermediate Shell to Lower Shell Circumferential Weld W05

- Lower Shell to Bottom Head Ring Circumferential Weld W04

• Power Distributions used in Benchmark Calculations

- Cycle 3, representative of Out-In (High Leakage) core design strategies

- Cycle 21, representative of Low-Leakage core design strategies

- A time-weighted average of power distributions through 54 EFPY, to provide fluence projection at 54 EFPY based on one cycle calculation 8

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Westinghouse RAI Response Calculations

• URE model - 209 radial, 195 azimuthal, and 89 axial mesh intervals TORT and RAPTOR-M3G runs are using the same geometry model, materials, and source distributions 9

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Westinghouse RAI Response Calculations

• MRE model - 209 radial, 195 azimuthal, and 85 axial mesh intervals TORT and RAPTOR-M3G runs are using the same geometry model, materials, and source distributions 10

Westinghouse Non-Proprietary Class 3 © 2015 Westinghouse Electric Company LLC. All Rights Reserved.

Westinghouse RAI Response Calculations

• LRE model - 209 radial, 195 azimuthal, and 91 axial mesh intervals Combining all three reduced size models would be a full core model similar to geometry model used in WCAP-17669-NP, but still not as refined.

11

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Westinghouse RAI Response Calculations

• Boundary Conditions and Extent of Applicability for the Reduced Size Models Parameter Reduced-Size Model URE MRE LRE Bottom of Model* 0.0 cm -191.206 cm -363.296 cm Bottom Boundary Condition Reflective Void Void Top of Model* 343.46 cm 190.289 cm 0.0 cm Top Boundary Condition Void Void Reflective Bottom Extent of Model Applicability* 75.0 cm -75.0 cm -330.0 cm Top Extent of Model Applicability* 300.0 cm 75.0 cm -75.0 cm Materials Analyzed in Model Weld W06 Weld W05 Weld W04

• Dimensions are given relative to the active core midplane URE - Weld 06 MRE - Weld 05 12 LRE - Weld 04

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Westinghouse RAI Response Calculation Results

• Calculated Neutron Fluence Rates for Catawba Unit 1 Cycle 3 Model Calculated Neutron (E>1.0 MeV)

Fluence Rate (Flux) [n/cm2-s]

Weld W06 Weld W05 Weld W04 Reduced-Size Models (TORT) with TW 1.06E+09 2.36E+10 1.91E+09 Reduced-Size Models (RAPTOR-M3G) with TW 1.06E+09 2.36E+10 1.90E+09 RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 1.06E+09 2.36E+10 1.90E+09 with TW RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 1.14E+09 2.33E+10 1.98E+09 TORT and RAPTOR-M3G with TW methods give identical results (<1%).

RAPTOR-M3G with DTW method yields more conservative results for limiting weld W06 13

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Westinghouse RAI Response Calculation Results

• Calculated Neutron Fluence Rates for Catawba Unit 1 Cycle 21 Model Calculated Neutron (E>1.0 MeV)

Fluence Rate (Flux) [n/cm2-s]

Weld W06 Weld W05 Weld W04 Reduced-Size Models (TORT) with TW 6.41E+08 1.54E+10 1.20E+09 Reduced-Size Models (RAPTOR-M3G) with TW 6.40E+08 1.54E+10 1.20E+09 RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 6.40E+08 1.54E+10 1.20E+09 with TW RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 6.98E+08 1.54E+10 1.26E+09 TORT and RAPTOR-M3G with TW methods give identical results (<1%).

RAPTOR-M3G with DTW method yields more conservative results for limiting weld W06 14

Westinghouse Non-Proprietary Class 3 © 2015 Westinghouse Electric Company LLC. All Rights Reserved.

Westinghouse RAI Response Calculation Results

• Calculated Neutron Fluence after 54 EFPY at Catawba Unit 1 (Reduced-Size Models calculated using time-weighted average power distributions)

Model Calculated Neutron (E>1.0 MeV)

Fluence [n/cm2]

Weld W06 Weld W05 Weld W04 Reduced-Size Models (TORT) with TW 1.05E+18 2.66E+19 1.83E+18 Reduced-Size Models (RAPTOR-M3G) with TW 1.05E+18 2.66E+19 1.83E+18 RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 1.05E+18 2.66E+19 1.83E+18 with TW (1.07E+18)* (2.63E+19)* (1.86E+18)*

RAPTOR-M3G Model in WCAP-17669-NP, Rev. 0 1.16E+18 2.60E+19 1.95E+18

• The projected 54 EFPY fluence value in the parenthesis is calculated by accumulating cycle-specific fluence for cycles 1 through 22, and assuming Cycle 22 at MUR power for cycles beyond Cycle 22, the same approach used in WCAP-17669-NP, Rev. 0 TORT and RAPTOR-M3G with TW methods give identical results (<1%).

RAPTOR-M3G with DTW method yields more 15 conservative results for limiting weld W06

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Westinghouse RAI Response Calculation Conclusions

• TORT and RAPTOR-M3G produce nearly identical results, i.e., within 1%, when using the same geometrical model and calculation control parameters

• The results from RAPTOR-M3G and TORT agree better than the 13% uncertainty assigned to the calculational methodology and well within the 20% uncertainty deemed acceptable for RTPTS and RTNDT determination

• The fast neutron fluence reported to NRC for the limiting material at 54 EFPY (upper shell to intermediate shell circumferential weld W06) in WCAP-17669-NP, Rev. 0 is the bounding value

• Therefore, the fast neutron flux / fluence values submitted to NRC in WCAP-17669-NP, Rev. 0 are acceptable 16

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Westinghouse RAI Response Calculation Conclusions

• The in-vessel surveillance capsule and ex-vessel neutron dosimetry data have been provided in WCAP-17669-NP, Rev. 0, Appendix C, the measurement-to-calculation comparisons show:

- The in-vessel dosimeters meet the +/-20% criteria for in-vessel surveillance capsules per Regulatory Guide 1.190

- The ex-vessel dosimeters meet the +/- 30% criteria for the cavity capsules per Regulatory Guide 1.190.

• Further sensitivity study has shown:

- Both the RAPTOR-M3G model used in WCAP-17669-NP, Rev. 0 and the reduced size models have achieved geometrical convergence, i.e., using much coarser mesh only changes the fluence results less than 2%.

- Using different quadrature sets (e.g., S12 vs. S8) only renders less than 3% difference in the calculated fluence values.

17

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Thank you !

Questions?

18