RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN

Transcription

1 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN FRAPCON/FRAPTRAN User Group Meeting 2014, Sendai, Japan, September 18, 2014 Presented by Jinzhao Zhang Co-authors: Adrien Dethioux, Thomas Drieu and Zeynab Umidova CHOOSE EXPERTS, FIND PARTNERS

2 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 2 TABLE OF CONTENT Introduction OECD RIA benchmark Phase II IAEA FUMAC EU NUGENIA-INFORMS Halden LOCA tests simulation and uncertainty analysis Problems reporting

3 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 3 INTRODUCTION Tractebel Engineering (GDF-SUEZ) the Architect Engineer and Owner s Engineer for all 7 operating PWRs in Belgium the Owner s Engineer for new NPPs to be built by the GDF-SUEZ group Tractebel Engineering is a member of the FRAPCON/FRAPTRAN users group since 2001 Participated in the user group meetings; Beta testing/error reporting ; Participated in the peer review of FRAPCON/FRAPTRAN (2013); Participated jointly with PNNL/UJV in the IAEA FUMEX-III project.

4 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 4 INTRODUCTION Key fuel rod design/safety issues at Tractebel Fission gas release (FGR) at high duty/burnup and transient conditions Rod internal pressure (no cladding lift-off) at high duty/burnup Cladding corrosion at high duty/burnup Pellet-Cladding Mechanical Interation (PCMI or PCI) during Condition II transients Impact on the flexibility and relaibility of the NPP operation (power modulations, ERPO, stretch-out) Evolutions of LOCA/RIA safety criteria (performance based cladding embrittlement criteria) Fuel behaviours at high burnups under LOCA/RIA (fuel fragmentation, relocation, dispersal, PCMI and high temperature failures) Fuel behaviours under design basis and beyond design basis accidents Impact on the safety of the NPP operation

5 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 5 INTRODUCTION Objectives: qualification of FRAPCON3.5/FRAPTRAN1.5 for applications to Independent verification of the fuel vendor s fuel rod design and modifications Independent verification of fuel vendors LOCA/RIA safety analysis and reloads fuel safety evaluation Qualify the fuel rod codes FRAPCON/FRAPTRAN for simulation of high burnup fuel behaviours during LOCA/RIA conditions; Develop a safety evaluation method for margin assessment regarding to the new LOCA/RIA safety criteria; Develop a method for independent verification of the safety analyses for demonstrating the compliance with the new LOCA/RIA safety criteria. Generation of fuel rod input data for neutronics codes Feasibility study for power modulation Operational support Licensing support

6 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 6 INTRODUCTION Approches: Review of development assessment and users assessment Independent assessment of code applicability for the target applications Application of statistical uncertainty and sensitivity analysis method by participating in the international fuel rod code benchmarks - IAEA FUMEX-III ( ) - OECD RIA benchmark Phase I ( ) - OECD RIA benchmark Phase II ( ) - IAEA FUMAC ( ) - EU NUGENIA-INFORMS ( ) - Halden LOCA tests simulation and uncertainty analysis ( ) -> developing safety evaluation method for NPPs LOCA/RIA margin assessment

7 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 7 OECD RIA BENCHMARK PHASE II RIA fuel rod codes benchmark OECD/NEA/CSNI Working Group on Fuel Safety (WGFS) Project ( ). Objectives Assess the ability of RIA fuel rod codes to reproduce the results from experiments and Evaluate the uncertainty associated with the calculated results for the relevant phenomena. Scope The first activity: to compare the results of different simulations on 8 simplified cases, in order to understand the differences in modelling of the concerned phenomena. The second activity: the assessment of the uncertainty of the results, in particular, the impact of the initial states and key models on the results of the transient.

8 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 8 OECD RIA BENCHMARK PHASE II Tractebel s participation Task 1: Use FRAPTRAN 1.5 for all 6 PWR cases Results were sent for comparisons with other participants Geometry TH conditions Contact Conditions Pmax (W) No gap He Pressure (bar) gap Fixed PWR BWR Bonding Slipping Thermal Case 1 X X X X X Mechanical Case 2 X X X X X Case 3 X X X X X Case 4 X X X X X Case 5 X X X X X TH Case 6 X X X X X Case 7 X X X X X Case 8 X X X X X

9 TRACTEBEL's ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD RIA BENCHMARK PHASE II Tractebel s participation Thermal and Mechanical models (case 1 3): No thermal difference Mechanical behaviour ok: Ex: Cladding strain Clad hoop strain : gap influence is predominant Clad axial strain : Contact pellet/clad condition is predominant. 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0 2,5 Clad total hoop strain (%) Case1 Case2 case Time (s) Clad total axial strain (%) Case1 Case2 case3 2 1,5 1 0,5 0-0, Time (s)

10 TRACTEBEL's ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD RIA BENCHMARK PHASE II Tractebel s participation Models with gap (case 2 and 3): 4,24 Fuel outer radius (mm) Case1 Case2 case3 4,22 Pellet/Gap homogenisation? 4,2 4,18 4,16 4,14 4,12 4, Time (s)

11 TRACTEBEL's ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD RIA BENCHMARK PHASE II Tractebel s participation TH models (case 4, 5 and 8): Thermal and mechanical behaviour OK Ex: - Clad hoop strain: Pmax is predominant + slight difference for a different He pressure. - Clad inner temperature: influence of Pmax but no difference due to He pressure. 2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0, Clad hoop strain (%) case4 case5 case Time (s) Clad inner temperature ( C) case4 case5 case Time (s)

12 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 12 IAEA FUMAC FUMAC = FUel Modelling in Accident Conditions IAEA Coordinated Research Project CRP ( ). Objectives Improvement and development of computer modelling codes Compilation and analysis of experimental data for codes validation for better understanding and enhanced safety of nuclear fuel behaviour in accident conditions Scope Focus on LOCA (DBA), in line with the early stage of the scenario of the Fukushima accident (BDBA) Assessment of the full core behaviour by means of coupled code systems, as well as the multi-dimensional analysis of pellet cladding interaction. Preparation of experimental data sets for code benchmarking, assessment of the content and format of available data, and definition of new experiments.

13 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 13 IAEA FUMAC Tractebel s participation Perform selected benchmark cases on the fuel behaviours during LOCA using the available or modified fuel rod codes FRAPCON/FRAPTRAN; Compare against data provided by the IAEA and OECD/NEA, and/or other code calculation results; Identify the weakness of the relevant models, and if possible, make necessary modifications in the codes, or if necessary and feasible, couple with other codes such as system thermal hydraulic code (RELAP or TRACE); Perform statistical uncertainty and sensitivity analysis for the selected cases with DAKOTA software. Benchmark cases to be agreed at the first RCM in Germany in November 2014.

14 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 14 EU NUGENIA-INFORMS INFORMS = Improved Nuclear Fuel OpeRational Modelling tools for Safety assessment NUGENIA joint R&D project within the European Union Euratom 7th Framework Program ( ). Objectives/Scope Improvement of the physical models for fuel and fission products behaviour Integration and benchmarking of the fuel performance and safety assessment codes for effective evaluation of fuel safety & performance (or source term management) in off-normal conditions including design basis accident conditions and spent fuel pool conditions

15 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 15 EU NUGENIA-INFORMS Tractebel s participation Identify gaps in FRAPCON/TRAN fission gas release models Assessment and benchmark of the FRAPCON/TRAN fuel rod codes with improved FGR models for steady state, power ramps, LOCA and RIA Benchmark cases to be agreed in 2015.

16 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 16 OECD HALDEN LOCA TEST SIMULATION FRAPCON/FRAPTRAN simulation of 5 Halden LOCA tests (PWR rods) IFA , 9-10 Focused on the relevant thermal and mechanical responses of fuel and cladding during LOCA Fuel temperatures fuel fragmentation and relocation cladding ballooning and burst (rupture) oxidation Objectives Check the ability of the FRAPTRAN code to predict or reproduce the measurements to identify the improvements to be made in the codes To identify the most important paramters for uncertainty analysis

17 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Simulation with FRAPCON/FRAPTRAN Pre-irradiation with FRAPCON Transient simulation by FRAPTRAN with imposed cladding outside temperatures Focus on the fuel rod responses of interest: rod internal pressure, ballooning, burst, ECR Modelling assumptions FRAPCON simulation of the refabricated rodlet at normal operation conditions Modification of the FRAPCON restart file used for initialization of FRAPTRAN model Refabricated rodlet pressure and gas content Use of FRAPTRAN Heat option for thermal mechanical calculations only Cladding temperature history imposed as the coolant temperature on the base of TCC1 measurements High heat transfer coefficients (HTC) imposed identical cladding and coolant temperatures

18 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Chosen models Fuel clad deformation: FRACAS I Rigid pellet model (default) Clad ballooning/burst: BALON2 failure model with empirical stress & strain limits (default) Fission gas release: Massih model (default) High temperature oxidation: Cathcart-Pawel model (C-P) Plenum gas temperature model modification The original rod gas plenum temperature model gave unsatisfactory results: too high temperature and rod internal pressure Modifications made to allow specification of an external plenum volume held at a defined constant gas temperature A arbitrary gas temperature of 127 C assumed for the whole transient Major source of uncertainties as the plenum gas temperature varies with time! Possible further improvement to the code by Imposing evolution of plenum gas temperature during transient, or Improving the gas plenum temperature model to calculate the plenum gas temperature

19 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Imposed cladding temperatures in two zones

20 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Evolution of best-estimate rod internal pressure Ballooning Burst

21 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis Objectives Identify the most important input parameters influencing the result of interest Evaluate the impact of the fuel rod data, model and test uncertainties on the uncertainties of the calculation results Identification of uncertainty parameters in three categories Fuel rod fabrication data Models Operation or test boundary conditions Selection of important uncertainty parameters Some parameters added for confirmation of importance Distributions and ranges taken as usually presented in literature Material properties not included

22 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: parameter range and distribution

23 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis Method and assumptions Monte-Carlo simple random sampling of all parameters with 93 FRAPCON/FRAPTRAN runs Use of first order: Min/Max are the lower and upper bounds (5/95 and 95/95, doublesided) Use of Pearson s and Spearman s correlation coefficients for sensitivity analysis Identification of the most influential parameters on the results of interest

24 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/14 24 OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: DAKOTA UA/SA process Fabrication Clad inner diameter Pellet outer diameter Resintering Cladding roughness Models Fuel thermal conductivity FGR model Fuel thermal expansion Corrosion model Boundary conditions Plenum temperature Cladding temperature Steady state power Transient power DAKOTA Clad inner diameter Pellet outer diameter Resintering Cladding roughness Fuel thermal conductivity FGR model Fuel thermal expansion Corrosion model Steady-State Power Cladding roughness Transient power Plenum temperature Cladding temperature FRAPCON input Restart file FRAPTRAN input Responses: - ECR, - strain, - pressure, DAKOTA UA/SA Results: - Lower/upper bounds - Correlations

25 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: evolution of rod internal pressure

26 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: evolution of average fuel temperature

27 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: evolution of cladding radial strain

28 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Uncertainty analysis: evolution of Cathcart-Pawel ECR

29 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ OECD HALDEN LOCA TEST SIMULATION Sensitivity analysis Pearson s linear correlation coefficients Designate the linear correlation between one input and one output. Absolute values less than 0.25 indicate week correlation. Absolute values between 0.25 and 0.75 indicate moderate correlation. Absolute values above 0.75 indicate strong correlation. Example: Fuel temperatures before burst at node 6 (close to burst position) Instant = 180 s, node 6 Av. Fuel T. Center T. Clad inner diameter 0,88 0,89 Pellet outer diameter -0,71-0,73 Resintering 0,42 0,43 Cladding roughness 0,10 0,09 Fuel thermal conductivity -0,97-0,98 Relative power during transient 0,94 0,96 Relative power during base irradiation 0,89 0,91 FGR model 0,54 0,57 Fuel thermal expansion 0,99 0,99 Steady state corrosion model 0,80 0,82 Plenum temperature 0,17 0,18 Cladding temperature 1,00 0,99

30 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ PROBLEMS REPORTING Floating point problem with Linux installation of FRAPTRAN 1.5 ( of 21/08/2014) After re-compiling FRAPTRAN 1.5 on Linux platform, we rerun some of the assessment cases. By comparison with windows pre-compiled version, we obtain very similar results (some last digit differences). However, for the cladding elastic hoop strain, the Linux version returned Infinity in some cases (MT1BR.in, PBF11C-R3.in and treatloca.in) while the Windows version returned a real number, as expected. Linux version cladding elastic hoop strain Infinity 0.000E E E E E +00 Windows version cladding elastic hoop strain 8.122E E E E E E+00 Is there any other known best practice to compile on Linux? The source code on cladding elastic strain may need to be verified.

31 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ PROBLEMS REPORTING FRAPTRAN 1.5 code failure after ballooning at high cladding temperatures ( of 20/02/2014) We use FRAPTRAN1.5 for performing an assessment of ECR C-P margins with respect to the new NRC LOCA criterion of ECR as function of the hydrogen content (i.e., burnup or corrosion thickness), using the PCT calculated in the current LOCA safety analysis. However, we have code failures due to probably the ballooning model if the specified PCT are higher than about 1100 C. What should be done if the ballooning model fails? We re trying the refined mesh, but it seems not working. Is this related to the modifications of the ballooning model in the new version to consider double sided oxidation? (Do you have a description of the modifications?) Is it related to the coding error in the energy conservation in the ballooning region in FRAPTRAN, as reported by SCK-CEN?

32 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ PROBLEMS REPORTING FRAPTRAN 1.5 code failure after ballooning at high cladding temperatures ( of 20/02/2014) Example of results:

33 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ PROBLEMS REPORTING FRAPTRAN 1.5 code failure after ballooning at high cladding temperatures ( of 20/02/2014) Example of results:

34 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ PROBLEMS REPORTING FRAPTRAN 1.5 code inconsistency on calculation of total ECR In cases similar to the previous, the results on total ECR seem not coherent with the calculated oxide thicknesses (ID+OD).

35 RECENT ACTIVITIES AND PLAN WITH FRAPCON/FRAPTRAN 18/09/ REFERENCES Jinzhao Zhang, Zeynab Umidova and Adrien Dethioux, "Simulation of Fuel Behaviours under LOCA and RIA Using FRAPTRAN and Uncertainty Analysis with DAKOTA," (IAEA Technical Meeting on Modelling of Water-Cooled Fuel Including Design Basis and Severe Accidents, Chengdu, China, 28 October 1 November, 2013) Jimmy Sudjana, Zeynab Umidova, Jinzhao Zhang, Maxime Haedens and Christophe Schneidesch, "Evaluation of PWR Rod Ejection Accident Margins Using PANTHER/COBRA and FRAPTRAN," (Proceedings of LWR Fuel Performance Meeting TopFuel 2013, Charlotte, NC, USA, September 15-19, 2013) A. Dethioux, Z. Umidova and J. Zhang, " Uncertainty analysis on FRAPTRAN simulation of the Halden LOCA tests IFA-650.4&5, (HPG Workshop on Data Uncertainties, Halden, Norway, September 4-5, 2013) Zeynab Umidova, Adrien Dethioux and Jinzhao Zhang, "Qualification of FRAPCON/FRAPTRAN Codes for Fuel Rod Design Verification and Reload Fuel Safety Evaluation", (Transactions of the 2012 International Meeting on LWR Fuel Performance (TopFuel 2012), Manchester, UK, 2-5 September, 2012)