Thermochemistry Model Development MS-16OR ORNL Thermochimica Update S. Simunovic, T. M. Besmann, B. Gaston, M. H. A. Piro December 1-4, 2015 2 Outline Introduction Development of thermodynamics models for nuclear fuels Thermochimica implementation in INL codes / Bison Summary 3 Introduction Thermochimica is an open-source software library for computing thermodynamic equilibria with the primary purpose of direct integration into multi-physics codes. The software is written in Fortran and it can be called from a Fortran, C, or C++ Application Programming Interfaces (API) on a desktop workstation or high performance computing environment. Software development began during M.H.A. Piros PhD at RMC, it evolved during a Post-Doctoral fellowship at ORNL and it is currently being maintained by M.H.A. Piro and S. Simunovic. 4 Brief Background Conditions for thermodynamic equilibrium: Gibbs Phase rule, Conservation of mass, and Global minimum of Gibbs energy at constant T & P (derived from first and second laws of thermodynamics). Thermodynamic equilibrium is assumed (i.e., time dependency is not considered). The appropriateness of this assumption is problem specific. This is generally a good assumption when temperature is high and time scale is long. 5 Species mole fraction Chemical Potential Element Mass Database Gibbs energy Moles of Phases Enthalpy Heat capacity Pressure T HERMO - CHIMICA Temper- ature Input Output 6 Nuclear Engineering Applications of Thermochimica Fuel performance and safety analysis: Fuel chemistry, Fuel melting, Reactive fission gas retention (predicting fission product speciation), Stress corrosion cracking (I-SCC) / Pellet-cladding interaction (PCI), and Zirconium hydriding. Potential applications (more development needed): Aqueous chemistry: CRUD formation, fuel storage, fuel transportation. 7 Highlights This project contributes to the NEAMS vision by Utilizing thermochemical models of oxide fuel to simulate chemical evolution during burnup Developing Thermochimica, an efficient thermochemical computational code for coupling to depletion calculations and transport codes Via Thermochmica, providing the thermodynamic values to phase field codes The focus for FY15 Continued expansion/refinement of a thermochemical database for oxide fuel- fission products and initiating efforts for metallic fuels The main accomplishments in FY15 were Expanded assessed thermodynamic models for the fluorite structure fuel phase with Mo and Zr components for use with Thermochimica in MBM Initiated modeling of metallic fuels Merged Thermochimica with Bison, and developed functions for supporting multicomponent reaction diffusion process Developed new algorithms for computing of thermodynamic equilibria 8 Highlights (cont.) Project will continue into FY16 Inclusion in state-of-the-art thermodynamic model for oxide nuclear fuels of key reactive elements such as cesium, rubidium, iodine and bromine Expansion of the metallic fuels thermochemical model with alternative alloy formulations in prioritized transuranic and fission product elements Development of models for multi-component reactive transport in LWR fuel materials based on thermodynamic models 9 Basis for Oxide Fuel Are U-O Thermodynamic Models U-O Phase Diagram O 2(g) Partial Pressure Predictions C. Gueneau, N. Dupin, B. Sundman, C. Martial, J.-C. Dumas, S. Gosse, S. Chatain, F. DeBruycker, D. Manara and R.J.M. Konings, J. Nucl. Mater., 419 (2011) (U 3+,U 4+,U 5+,U 6+,M X+,M Y+,) 1 (O 2-,Va 0 ) 2 (O 2-,Va 0 ) 1 Fuel Fluorite Structure Phase 3-Sublattice Model 10 Important Zr and Mo FPs Need Models of Dissolution in UO 2 Thermochemical Models Ellingham diagram indicating oxygen potential for oxide phase formation Sublattice models for Zr in urania yield computed UO 2 -ZrO 2 and U-Zr-O phase diagrams 11 Mo and Zr Added to Oxide Fuel Models, Continuing Fuel Modeling Expansion Although U-Mo-O not yet fully assessed, models for the system exist and were incorporated in broader fuel model Current fuel model status M are assessed for the systems and have been added to the models M are added but not yet included as assessed Y Gd Ce Pr Nd Th Zr Ba Te Cs Mo Sr 12 Example: Mo and Zr Partitioning in Fuel Phases Important for Oxygen Behavior Mo Zr Partitioning among fuel phases at typical PWR 72.5 GWd/t burnup 13 Initiated Development of Transmutation/Fast Reactor Metallic Fuel Models: U-Pu-Zr, U-Mo Computed Phase Diagrams for U-Pu-Zr and U-Mo Solidus contours for U-Pu-Zr Regular Solution Model for Used Alloy Systems (binary example) M Kurata, IOP Conf. Series: Materials Science and Engineering 9 (2010) A. Berche, et al., Journal of Nuclear Materials 2011, 411 (1-3), 14 Oxide and Metallic Fuels Thermochemical Models/Values in Thermochimica The well-advanced models for oxide fuel are formatted for use in thermochimica Fluorite structure fuel phase with Pu, rare earths, Mo, and Zr Secondary oxide phases using preliminary models White or noble metal phases Vapor species Initial models of metallic transmutation/fast reactor fuel alloys now in Thermochimica data format U-Pu-Zr phases U-Pu-Mo, with only U-Mo assessed and no ternaries 15 https://www.oecd-nea.org/science/docs/2015/nsc-r pdf 16 Implementation of Thermochimica in the INL Codes Thermochimica library has been reorganized and is now a separate module in the INL Gitlab system The library can be compiled separately It has 58 validation tests The library must be downloaded and placed in the same directory as the application using the library User manual is included in the package New methods are implemented for global optimization calculations M.H.A. Piro, S. Simunovic; Global optimization algorithms to compute thermodynamic equilibria in large complex systems; J Comp Mat Sci; under review. 17 Implementation of Thermochimica in the INL Codes Thermochimica-based models were merged into Bison Bison tests: Zr-H system, Zr hydride formation and H diffusion Fuel model, initial conditions with oxygen diffusion Mihaela, et., J Nuclear Materials 394 (2009) Fuel model, aux kernel routines for various oxygen calculations Bison examples: Using Bison burnup models for calculation of thermodynamic quantities Need more detailed depletion model in Bison to take advantage of thermodynamics Currently using MPACT, ORIGEN in separate calculations 18 Example: Zr-H System and H Diffusion void MaterialHZrH::computeQpProperties(){ // Hydride phases to search for in eq. solution, comma delimitated char s1[] = "ZRH2_DELTA,ZRH2_EPSILON"; // read model data file, read only once FORTRAN_CALL(Thermochimica::ssinitiatezrhd)(); FORTRAN_CALL(Thermochimica::ssparsecsdatafile)(); // Set temperature and pressure for thermochemistry solver FORTRAN_CALL(Thermochimica::settemperaturepressure)(&Temperature, &Pressure); iElement=40; FORTRAN_CALL(Thermochimica::setelementmass)(&iElement, &dBMol); // Zr iElement=1; FORTRAN_CALL(Thermochimica::setelementmass)(&iElement, &dAMol); // H // calculate thermochemical equilibrium FORTRAN_CALL(Thermochimica::thermochimica)(); // check for error status FORTRAN_CALL(Thermochimica::checkinfothermo)(&idbg); // difference in hydrides to be stored for source rate calculation _dhhydride[_qp] = _hhydride[_qp] - _hhydride_old[_qp]; } 19 Example: Oxygen-related Calculations Real OxygenThermochimicaAux::computeValue(){ // Read in thermodynamics model, only once FORTRAN_CALL(Thermochimica::ssparsecsdatafile)(); iElement=94; dMol=_elPu[_qp]; FORTRAN_CALL(Thermochimica::setelementmass)(&iElement, &dMol); // iElement=92; dMol=_elU[_qp]; FORTRAN_CALL(Thermochimica::setelementmass)(&iElement, &dMol); // // calculate thermochemical equilibrium FORTRAN_CALL(Thermochimica::thermochimica)(); FORTRAN_CALL(Thermochimica::compotomratio)(cCEFFtn, &dO2M, &idbg); iElement=_o2idx; FORTRAN_CALL(Thermochimica::getmolfraction)(&iElement, &dMolFraction, &idbg); iElement=_oidx; FORTRAN_CALL(Thermochimica::getelementpotential)(&iElement, &dElementPotential, &idbg); dIdealConstant = ; dO2PPressure = dIdealConstant * Temperature * log(dMolFraction); dO2Potential = 2.0 * dIdealConstant * Temperature * dElementPotential; _o2m[_qp] = dO2M; _o2dg[_qp] = dO2Potential; return dO2PPressure; } 20 Input: Oxygen-related Calculations [AuxKernels] [./opp] type = OxygenThermochimicaAux variable = oxypp O = el_o U = el_u Pu = el_pu O2idx = 2 Oidx = 3 temp = temp pressure = 1.0 thermofile = DBV8_TMB_modified.dat cefuo2 = 'O2ZRU_C' tunit = 'K' punit = 'atm' munit = 'moles' o2m = o2m o2dg = o2dg execute_on = timestep_end [../] [] 21 Results: Oxygen-related Calculations Various thermodynamics data can be accessed via Thermochimica API New examples are being added for multicomponent reaction- diffusion problems K J/mol TemperatureRT ln(P O2 )O/M 22 Integration with Existing Burnup Models in BISON [Burnup] [./burnup] block = pellet_type_1 rod_ave_lin_pow = power_history axial_power_profile = axial_peaking_factors num_radial = 80 num_axial = 11 a_lower = 2.49e-3 a_upper = 2.621e-2 fuel_inner_radius = 0 fuel_outer_radius =.0041 N235 = N235 N238 = N238 N239 = N239 N240 = N240 N241 = N241 N242 = N242 RPF = RPF [../] [] [AuxKernels] [./opp] type = OxygenPPressureAux variable = opp o2m = o2m temp = temp pressure = 1.0 thermofile = Pu_U_O_CEA.dat O2idx = 2 O = e+28 N235 = N235 N238 = N238 N239 = N239 N240 = N240 N241 = N241 N242 = N242 block = pellet_type_1 execute_on = timestep [../] [] 23 Integration with Existing Burnup Models in BISON (a) Temperature [K], and (b) oxygen potential [J/mol] for time s (5.2 hr) (a)(b) 24 Integration with Existing Burnup Models in BISON (a) Oxygen potential [J/mol] and (b) oxygen to metal ratio at e+07 s (154 days) (a)(b) 25 Summary Expanded assessed thermodynamic models for the fluorite structure fuel phase with Mo and Zr components for use with Thermochimica in MBM Initiated modeling of metallic fuels Merged Thermochimica with Bison, and developed functions for supporting multicomponent reaction diffusion process Developed new algorithms for computing of thermodynamic equilibria