ML18249A237
| ML18249A237 | |
| Person / Time | |
|---|---|
| Site: | PROJ0728, 99902041 |
| Issue date: | 04/25/2019 |
| From: | Rowley J NRC/NRR/DSS/SNPB |
| To: | Peters G Framatome |
| Rowley J, NRR/DLP/PLPB, 415-4053 | |
| Shared Package | |
| ML18249A225 | List: |
| References | |
| ANP-10346P, EPID L-2017-TOP-0067 | |
| Download: ML18249A237 (10) | |
Text
REPORT OF THE AUDIT CONDUCTED JUNE 11 - 13, 2018, IN SUPPORT OF THE REVIEW OF TOPICAL REPORT ANP-10346P, REVISION 0 ATWS-I ANALYSIS METHODOLOGY FOR BWRS USING RAMONA5-FA PROJECT NO. 728/DOCKET NO. 99902041 EPID: NO. L-2017-TOP-0067
1.0 INTRODUCTION
By letter dated December 15, 2017, Framatome Inc. (Framatome previously AREVA) submitted a topical report (TR) which presents a methodology for the evaluation of the Anticipated Transient Without Scram (ATWS) with Instability (ATWS-I) for boiling water reactors (BWRs) using a recent version of the RAMONA5-FA methodology. The TR is entitled, ATWS-I Analysis Methodology for BWRs Using RAMONA5-FA, and can be identified by TR number ANP-10346P.
The TR provides a proposed generic methodology for licensing the extended flow window (EFW) operation, an extension of the operating domain, of BWR Type 3 to BWR Type 6 plants with regard to ATWS-I. The method aims at addressing the fuel specific impacts of the ATWS-I event and utilizes the RAMONA5-FA computer code. The approved version of RAMONA5-FA has been modified to be capable of simulating the severe power and flow oscillations associated with core instabilities unsuppressed with scram. The TR also proposes a calculation procedure to define the process and conservatisms to be used in licensing calculations.
The audit was held at the Framatome facilities at 2101 Horn Rapids Road in Richland, WA, from June 11 through June 13, 2018. During this meeting, the U.S. Nuclear Regulatory Commission (NRC) staff performed an in-depth audit of ANP-10346P and supporting documentation to identify appropriate additional information to request for submittal. Such information would be that required to determine (1) whether the proposed methodology for analysis of the ATWS-I event is supported by the assessments and technical justifications provided by Framatome and (2) whether the ATWS-I analysis methodology, as described in ANP-10346P, is sufficient to meet the aforementioned regulatory requirements and NRC guidance.
NRC Audit Team:
Scott Krepel - Nuclear performance and Code Review Branch, Division of Safety Systems (DSS), Office of Nuclear Reactor Regulation (NRR)
Ashley Smith - Reactor System Branch, DSS, NRR Aaron Wysocki - Contractor, Oak Ridge National Laboratory Jonathan Rowley - Licensing Processes Branch, NRR Enclosure 2
Framatome Staff:
Ken Greene Robert Schnepp Daniel Tinkler Kevin Quick Yousef Farawila Cameron Myers Doug Pruitt Alan Meginnis 2.0 DOCUMENTS AUDITED The following documents were made available to the NRC staff for review during the audit.
Document Number: Document
Title:
- 1. FS1-0028706 Rev 1 ATRIUM 10XM Stability Test STS-115.1 Deck Using RAMONA5-FA
- 2. FS1-0032505 Rev 1 Analysis of ATRIUM 10XM Stability Test STS 115.1 Using RAMONA5-FA
- 3. FS1-0032906 Rev 1 Analysis of ATRIUM 10XM Pressure Drop Test Using RAMONA5-FA
- 4. FS1-0032907 Rev 1 Re-Analysis of ATRIUM-10 Decay Ratio Benchmarks Using RAMONA5-FA
- 5. FS1-0032908 Rev 1 Analysis of ATRIUM-10 KATHY Pressure Drop Test Using RAMONA5-FA
- 6. FS1-0025502 Rev 1 RAMONA5-FA Input Deck for Oskarshamn-2 Stability Event Benchmark
- 7. FS1-0025870 Rev 1 [
]
- 8. STAIF Benchmarking Calculations based on FS1-0025811 Rev 1 MICROBURN-B2 Version 1: KKK, KKI, KRB-B, KRB-C, PB2, and WNP2
- 9. FS1-0032449 Rev 1 [ ] from KATHY Tests
- 10. FS1-0032731 Rev 1 Critical Power Reduced Order Model (CPROM) ATRIUM 10XM Application to Generic ATWSi
- 11. FS1-0033277 Rev 1 Cyclical Dryout and Rewetting Model for Generic ATWSi Methodology with Benchmarking to ATRIUM 10XM Stability Tests
- 12. FS1-0034008 Rev 1 Brunswick RAMONA5-FA Input Deck Development for ATWS-I Analyses
- 13. FS1-0034930 Rev 1 Void Fraction Benchmarking for RAMONA5-FA
- 14. FS1-0035033 Rev 1 Oskarshamn-2 Stability Event Benchmark with RAMONA5-FA
- 15. FS1-0035092 Rev 1 Brunswick ATWS-I Sample Problem
- 16. FS1-0035149 Rev 1 BWR-A Stability Event Benchmark with RAMONA5-FA
- 17. FS1-0031790 Rev 2 FSQA-05-RAMONA5-FA-UAPR17_SRelD-0
- 18. ANP-3274P Rev 3 Analytical Methods for Monticello ATWS-I
- 19. FS1-0038040 Rev 1 Rebenchmarking with Corrected Fuel Rod Properties
- 20. [ ] [
]
- 21. [ ] [
]
- 22. [ ] [
]
- 23. FSOP-21 Developing Computer Codes
- 24. ANP-3614P, Revision 0 Phenomenon Identification and Ranking for Boiling Water Reactor ATWS with Instabilities
- 25. FS1-0031792 Rev 1 RAMONA5-FA Theory Manual: A Computer Program for BWR Transient Analysis in the Time Domain
- 26. FS1-0007160 Revision 8 RAMONA5-FA Users Manual: A Computer Program for BWR Transient Analysis in the Time Domain
- 27. Draft Guideline ATWS with Core Instability Guideline
- 28. FS1-0036703 Rev 1 [
]
- 29. NS&T, 1996 Paper A Study of Nonlinear Oscillation and Limit Cycles in BWRs Part 1 - The Global Mode
- 30. NS&T, 1996 Paper A Study of Nonlinear Oscillation and Limit Cycles in BWRs Part 2 - The Regional Mode
- 31. FS1-0032907 Rev 1 ATWS-I Analysis Methodology for using RAMONA5-FA
- 32. Nuclear Engineering & Design Numerics of Codes and Stability Diffusion and Convergence
- 33. NUREG/CR-5816 BWR Stability Analysis with the BNL Engineering Plant Analyzer
- 34. Progress in Nuclear Comments on Local Power Oscillation Phenomenon at Energy 60 (212) 73-88 BWRs
- 35. BWR-10255PA Rev 2 Cycle-Specific DIVOM Methodology Using the RAMONA5-FA Code
- 36. NURETH15-457 TRACE/PARCS Analysis of Out-of-phase Power Oscillations with a Rotating Line of Symmetry
- 37. NS&T, Vol 38, No 5 2001 Paper Nonlinear Behavior under Regional Neutron Flux Oscillations in BWR Cores
- 38. Trans. Am. Nucl. Soc., Vol. 99, Considerations for Bypass Boiling during BWR Power pp. 739-740 (Nov. 2008) Oscillations
- 39. Topfuel Paper 92, 2010 Stability and Void Fraction Measurements for the ATRIUM 10XM BWR Fuel Bundle
- 40. 2011 Jahrestagung Full Scale Stability and Void Fraction Measurements Kerntechnik, Berlin, Germany, for the ATRIUM 10XM BWR Fuel Bundle May 17-19 2011
- 41. [ [
]
]
- 42. Nuclear Simulation of Two-Phase Flow in Complex Systems Technology Vol. 159, September 2007
- 43. Ph.D. Thesis, Oregon State Nodal Methods for Calculating Nuclear Reactor University, OSU-NE-9108, Transients, Control Rod Patterns, and Fuel Pin June 1991 Powers
- 44. EMF-2158(P)(A) Revision 0 Siemens Power Corporation Methodology for Boiling Water Reactors: Evaluation and Validation of CASMO-4/MICROBURN-B2
- 45. EMF-CC-074(P)(A) Volume 4 BWR Stability Analysis - Assessment of STAIF with Revision 0 Input from MICROBURN-B2
- 46. EMF-3028P-A Volume 2 RAMONA5-FA: A Computer Program for BWR Revision 4 Transient Analysis in the Time Domain Volume 2 --
Theory Manual
- 47. ANSI/ANS-5.1-1979 American National Standard for Decay Heat Power in Light Water Reactors
- 48. BNL-NUREG-51748 A Description and Assessment of RAMONA-3B Mod.
0 Cycle 4 A Computer Code with Three-Dimensional Neutron Kinetics for BWR System Transients
- 49. [ [ ]
]
- 50. [ ] [ ]
- 51. [ ] [
]
- 52. Second edition 2008 Springer- International Steam Tables - Properties of Water and Verlag Berlin Heidelberg Steam Based on the Industrial Formulation IAPWS-IF97
- 53. ANP-10262PA Revision 0 Enhanced Option III Long Term Stability Solution
- 54. NUREG/CR-6743, Phenomenon Identification and Ranking Tables LA-UR-00-3122 (PIRTS) for Power Oscillations Without Scram in Boiling Water Reactors Containing High Burnup Fuel
- 55. FRIGG-3, R-494/RL-1154, Hydrodynamic and Heat Transfer Measurements on A November 1969 Full-Scale Simulated 36-Rod Marviken Fuel Element with Non-Uniform Radial Heat Flux Distribution
3.0 AUDIT ACTIVITIES 3.1. PRESENTATION/OVERVIEW OF ANP-10346P Framatome opened the audit by presenting an overview of the evolution of the methodology in the TR. This presentation included information about the approved DIVOM methodology based on RAMONA5-FA, plant-specific ATWS-I methodology with AISHA and SINANO codes, and the current generic ATWS-I application.
3.2. REVIEW OF CONDITION REPORT 2018-3932 Framatome presented a discussion of the condition report that triggered a revision to the calculations supporting ANP-10346P. The discussion included a description of the error, corrective actions, and impacts on the results.
During recent code development an error was found in the calculation of the [
]
3.3. WALKTHROUGH OF CALCULATIONAL PROCEDURE Framatome gave a step-by-step explanation of the calculational procedure for the ATWS-I event as described in Section 8 of the TR. The walkthrough gave the NRC staff a better understanding of the procedure that a licensee will use to run calculations using this methodology. Additional information will be requested by the NRC staff regarding the quantification of sufficient margin between the licensing basis operator action time and the time of oscillation onset as described in Step 3b of the procedure.
3.4. AUDIT QUESTIONS Framatome presented answers to each question from the Audit Plan (Agencywide Documents Access and Management System Accession No. ML18192A550) followed by a discussion. A summary of the discussions are included in the following sections.
3.4.1. Fuel Rod Model At the audit, the applicant provided results for time-dependent gap conductance during a turbine trip with bypass (TTWBP) event in a representative channel, to assist the NRC staff in understanding the importance of this model with respect to meeting the ATWS acceptance criteria. [
]
Specific details of the ['''''''''''''' '''' ''''''''''] were discussed, which improved the NRC staffs understanding of the model and will assist the NRC staff in its regulatory determination.
3.4.2. Fitting of Parameters to Data As discussed at the audit, all parameters in constitutive models were evaluated and fitted in one of the following ways:
[ ]
[ ]
[ ]
[ ]
[
]
The NRC staffs examination of various parameter fittings - particularly the CPROM parameters - allowed the NRC staff to better understand the applicants approach and justifications for the parameter values that were chosen. From examination, the models such as CPROM appeared to capture the underlying physical phenomena sufficiently well so that few parameters needed to be fit to the data, and a clear and well-defined fitting process was used to determine their values. The NRC staff did not find evidence that any parameters were defined in a hand-waving or arbitrary fashion which may have led to unintentionally nonphysical behavior in the range of application of these models.
3.4.3. Axial Nodalization The NRC staff had concerns that the axial nodalization used in the TR methodology could lead to significant numerical errors in the calculation of the time-dependent behavior during ATWS-I, including decay ratios. [
]:
- 1. [
]
- 2. [
]
[
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3.4.4. [''''''''''''' ''''''''''''' '''''''']
TTWBP results including detailed results for the [''''''''''''' '''''''''''''' '''''''] below the active fuel were examined during the audit. The NRC staff found that, [
]
3.4.5. Addition of Numerical Noise The application of numerical noise to the simulation was discussed in depth. [
] The NRC staff may potentially ask an RAI for further examination and/or discussion of the adequacy of the modeling approach for numerical noise.
3.4.6. Input Deck Walkthrough The applicant walked the NRC staff through a sample RAMONA5-FA input deck to provide the NRC staff with an understanding of what input values and modeling options are changeable via the input file and what (if any) modeling flexibilities are provided to the user.
When performing ATWS-I calculations, [
] This provided the NRC staff with increased assurance that, hypothetically, users would not be allowed to adjust input parameters at will to affect the code results.
3.5. EXIT MEETING At the conclusion of the audit, an exit meeting was held to summarize the additional information that Framatome will be requested to submit to continue the review. The NRC staff and Framatome representatives agreed on a path forward for each question from the Audit Plan and any other review items that arose during the audit. The intent of this meeting was not to direct Framatome to submit this information, rather, it provided an early clarification opportunity for potential RAIs.