Ants Cerberus input/output manual

Ants may take input and give output variables and fields from or to Cerberus. Many input variables are shared with the Ants input file and some are only possible to be given via Cerberus.

Note that some of the Ants output fields are updated from the data given in the input fields or variables only after a subsequent solve call.

Input variables

Name	Size and type	Availability	Explanation	Related input cards	Notes
Ants_iv_boron	1*float64		Global value for coolant boron content (ppm) to be used in all nodes or an initial value of boron if it is used as control variable.	iteration boron	If both this variable and Ants_if_boron_concentration are given, the last one sent to Ants will be used.
Ants_iv_control_variable	1*int64		Set the control variable for critical variable iteration.	iteration control_variable	See cerberus.krakendefs.ants.AntsControlVar
Ants_iv_convergence_criterion_boron	1*float64			iteration conv_crit_boron
Ants_iv_convergence_criterion_fission_source	1*float64			iteration conv_crit_fsrc
Ants_iv_convergence_criterion_fission_source_l2	1*float64			iteration conv_crit_fsrc_l2
Ants_iv_convergence_criterion_flux	1*float64			iteration conv_crit_flux
Ants_iv_convergence_criterion_keff	1*float64			iteration conv_crit_keff
Ants_iv_convergence_criterion_partial_current	1*float64			iteration conv_crit_partial_current
Ants_iv_convergence_criterion_poison_density	1*float64			iteration conv_crit_poison_density
Ants_iv_convergence_criterion_power	1*float64			iteration conv_crit_power
Ants_iv_corrector_method	1*int64		Which type of corrector time integration to use for depletion?		See cerberus.krakendefs.ants.AntsCorrector
Ants_iv_corrector_num_substep	1*int64		Number of depletion substeps to take on corrector. Default: ??
Ants_iv_cr_bank_height_<identifier>	1*float64	If controlrod group load is defined in input.		controlrod group height	Defined as height of CR lowest end from geometry bottom.
Ants_iv_critical_node_method	1*int64			iteration critical_node_method	See cerberus.krakendefs.ants.AntsCriticalNodeMethod
Ants_iv_critical_node_shift	1*float64			iteration critical_node_shift
Ants_iv_critical_node_shift_increment	1*float64
Ants_iv_decay_num_substep	1*int64		Number of depletion substeps to take during decay. Default: ??
Ants_iv_depletion_type	1*int64		The type of solution used for depleting materials.		See cerberus.krakendefs.ants.AntsDepStyle
Ants_iv_disable_abundant_messages	1*int64		If set to 1, disables some abundant warning messages from Ants, printing of which may slow down the calculation. Default value: 0.
Ants_iv_eigenvalue_critical_limit	1*float64			iteration eigenvalue_critical_limit
Ants_iv_eigenvalue_critical_limit_fix_sign	1*float64
Ants_iv_eigenvalue_real_limit	1*float64			iteration eigenvalue_real_limit
Ants_iv_keff	1*float64		Input effective multiplication for boron iteration (Ants_iv_control_variable) or transient calculations, or an initial value for effective multiplication factor iteration. Default: 1.0
Ants_iv_normalization_variable	1*int64		Set the variable to which the neutronics solution is normalized or disable normalization.	iteration normalization_type	See cerberus.krakendefs.ants.AntsNormalization
Ants_iv_num_datafield_point	1*int64		Number of points for which coordinates (Ants_iv_datafield_xyz) will be provided to evaluate point-wise homogeneous flux (Ants_ov_datafield_flux).
Ants_iv_num_inner_iteration	1*int64		Number of neutronics inner iterations per outer iteration.	iteration num_inner
Ants_iv_poison_ff	1*float64		Factor for accelerating the time in the evaluation of poison concentrations. Default 1.0.		A factor of 10, for example, means that for 1 second of transient simulated, the poison concentrations are updated as if 10 seconds have been elapsed.
Ants_iv_predictor_method	1*int64		Which type of predictor time integration to use for depletion?		See cerberus.krakendefs.ants.AntsPredictor
Ants_iv_predictor_num_substep	1*int64		Number of depletion substeps to take on predictor. Default: ??
Ants_iv_reset_neutronics_state	1*int64		If set to 1, the internal neutronics solution of Ants will be reset and the next solution will begin from that state.		Can be used e.g. for resetting Ants between single-node solutions for different node types.
Ants_iv_samarium_state	1*int64		State of samarium chain nuclides during calculation.	iteration samarium_state	See cerberus.krakendefs.ants.AntsSamarium
Ants_iv_total_power	1*float64		Set the core total power (W) for flux normalization.	iteration power
Ants_iv_xenon_state	1*int64		State of xenon chain nuclides during calculation.	iteration xenon_state	See cerberus.krakendefs.ants.AntsXenon

Input fields

Base name	Suffix	Mesh	Type	Units	Explanation	Notes
Ants_if_boron_concentration		Calculation node	float64	ppm	Local boron concentration.	If both this field and Ants_iv_boron are given, the last one sent to Ants will be used. If boron is used as control variable, this data will not be used.
Ants_if_burnup		Calculation node	float64	J/kg	Local burnup.	Burnup is not taken into account when initializing Ants micro depletion nuclide fields, if it is not especially requested with Ants_if_mdep_number_density.
Ants_if_coolant_density		Calculation node	float64	kg/m3	Local coolant density.
Ants_if_coolant_density_unheated		Calculation node	float64	kg/m3	Local coolant density in bypass / unheated channel.
Ants_if_coolant_mean_historical_density		Calculation node	float64	kg/m3	Local mean historical coolant density.
Ants_if_coolant_temperature		Calculation node	float64	K	Local coolant temperature.
Ants_if_datafield_xyz		Datafield	float64	m	Input coordinates (x0, y0, z0, x1, y1, z1, ...) for a set of points in which the homogeneous flux can be polled (Ants_of_datafield_flux).
Ants_if_fission_source_expansion_coeff	_poly_<poly>_group_<group>	Calculation node	float64		Coefficients of polynomial fission source expansion.	Used in transient calculations and transient restarts.
Ants_if_flux_expansion_coeff	_poly_<poly>_group_<group>	Calculation node	float64		Coefficients of polynomial flux expansion.	Used in transient calculations and transient restarts.
Ants_if_fuel_temperature		Calculation node	float64		Local fuel temperature.
Ants_if_mdep_number_density		Calculation node	float64	1/m3		If any value is below -1E-56 for a node and region, the values will be initialized from the group constant data nominal values according to current node burnup values.
Ants_if_min_eigenvalue_calculated		Calculation node	float64	unitless	The smallest (absolute) local node eigenvalue calculated, before critical node treatments were applied.
Ants_if_min_eigenvalue_used		Calculation node	float64	unitless	The smallest (absolute) local node eigenvalue used, after critical node treatments were applied.
Ants_if_netcurrent	_group_<group>_moment_<moment>	Calculation node	float64		Local node net neutron current moments.
Ants_if_num_pin		Calculation node	int64		Number of pins in the local node.	Can be used when giving group constants through Cerberus.
Ants_if_number_density_i135		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_np239		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_pm149		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_pu239		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_sm149		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_u238		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_xe135		Calculation node	float64	1/m3	Local number density.
Ants_if_number_density_xe135m		Calculation node	float64	1/m3	Local number density.
Ants_if_outcurrent	_group_<group>_moment_<moment>	Calculation node	float64		Local node outwards neutron current moments.
Ants_if_ppr_form_function	_group_<group>	Calculation node pin	float64	unitless	Local pin power form functions.	Used for fixed group constant calculations.
Ants_if_ppr_wx		Calculation node pin	float64	m	Local pin cell x widths.	Used for fixed group constant calculations.
Ants_if_ppr_wy		Calculation node pin	float64	m	Local pin cell y widths	Used for fixed group constant calculations.
Ants_if_ppr_x		Calculation node pin	float64	m	Local pin cell centroid x-coordinates.	Used for fixed group constant calculations.
Ants_if_ppr_y		Calculation node pin	float64	m	Local pin cell centroid y-coordinates.	Used for fixed group constant calculations.
Ants_if_precursor_expansion_coeff	_poly_<poly>_precursor_group_<precgroup>	Calculation node	float64		Coefficients of polynomial precursor number density expansion.	Used in transient calculations and transient restarts.
Ants_if_supernode_boron_concentration		Input node	float64	ppm	Local boron concentration given for input nodes.
Ants_if_supernode_coolant_density		Input node	float64	kg/m3	Local coolant density given for input nodes.
Ants_if_supernode_coolant_density_unheated		Input node	float64	kg/m3	Local coolant density in bypass / unheated channel given for input nodes
Ants_if_supernode_coolant_temperature		Input node	float64	K	Local coolant temperature given for input nodes
Ants_if_supernode_fuel_temperature		Input node	float64	K	Local fuel temperature given for input nodes.
Ants_if_supernode_ppr_burnup		Input node	float64	MWd/kgU	Local pin burnup given for input nodes.
Ants_if_xs_absorption	_group_<group>	Calculation node	float64	1/m	Local absorption cross section.	Used for fixed group constant calculations.
Ants_if_xs_beta	_precursor_group_<precgroup>	Calculation node	float64	unitless	Local delayed neutron fraction.	Used for fixed group constant calculations.
Ants_if_xs_chi_delayed	_group_<group>	Calculation node	float64	unitless	Local delayed fission neutron spectrum.	Used for fixed group constant calculations.
Ants_if_xs_chi_prompt	_group_<group>	Calculation node	float64	unitless	Local prompt fission neutron spectrum.	Used for fixed group constant calculations.
Ants_if_xs_chi_total	_group_<group>	Calculation node	float64	unitless	Local total fission neutron spectrum.	Used for fixed group constant calculations.
Ants_if_xs_diffusion	_group_<group>	Calculation node	float64	m	Local diffusion coefficient.	Used for fixed group constant calculations.
Ants_if_xs_discontinuityfactor	_group_<group>_moment_<moment>	Calculation node	float64	unitless	Local flux moment discontinuity factor.	Used for fixed group constant calculations.
Ants_if_xs_fission	_group_<group>	Calculation node	float64	1/m	Local fission cross section.	Used for fixed group constant calculations.
Ants_if_xs_inversevelocity	_group_<group>	Calculation node	float64	s/m	Local inverse velocity.	Used for fixed group constant calculations.
Ants_if_xs_kappafission	_group_<group>	Calculation node	float64	J/m	Local fission energy production cross section.	Used for fixed group constant calculations.
Ants_if_xs_lambda	_precursor_group_<precgroup>	Calculation node	float64	1/s	Local precursor decay constant.	Used for fixed group constant calculations.
Ants_if_xs_nufission	_group_<group>	Calculation node	float64	1/m	Local fission neutron production cross section.	Used for fixed group constant calculations.
Ants_if_xs_removal	_group_<group>	Calculation node	float64	1/m	Local removal cross section.	Used for fixed group constant calculations.
Ants_if_xs_scattering	_group_<fromgroup>_group_<togroup>	Calculation node	float64	1/m	Local group to group scattering cross sections.	Used for fixed group constant calculations.

Output variables

Name	Size and type	Availability	Explanation	Notes
Ants_ov_boron	1*float64		Current global boron (ppm).
Ants_ov_convergence_criterion_boron	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_fission_source	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_fission_source_l2	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_flux	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_keff	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_partial_current	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_poison_density	1*float64		Current value for the convergence limit
Ants_ov_convergence_criterion_power	1*float64		Current value for the convergence limit
Ants_ov_convergence_parameter_boron	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_fission_source	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_fission_source_l2	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_flux	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_keff	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_partial_current	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_poison_density	1*float64		Current evaluated value for convergence parameter
Ants_ov_convergence_parameter_power	1*float64		Current evaluated value for convergence parameter
Ants_ov_cr_bank_height_<identifier>	1*float64	If controlrod group load is defined in input.	Current axial height (cm) of this control rod identifier.	Height of CR lowest end from geometry bottom.
Ants_ov_is_boron_global	1*int64		Does group constant evaluation currently use a global (1) or calculation-node-local (0) value for boron?
Ants_ov_keff	1*float64		Current value for keff. Either evaluated for current boron or given as input.
Ants_ov_max_mdep_nuclide	1*int64		Maximum number of microdepletion nuclides in any region of any material in the calculation.
Ants_ov_max_mdep_region	1*int64		Maximum number of microdepletion regions in any material in the calculation.
Ants_ov_mean_burnup	1*float64		Mean burnup in the system.	Calculated correctly from fueled parts?
Ants_ov_min_eigenvalue_calculated	1*float64		The smallest (absolute) local node eigenvalue calculated, before critical node treatments were applied.
Ants_ov_min_eigenvalue_used	1*float64		The smallest (absolute) local node eigenvalue used, after critical node treatments were applied.
Ants_ov_num_group	1*int64		Number of neutron groups in the calculation.
Ants_ov_num_moment	1*int64		Number of directional flux moments in the calculation.
Ants_ov_num_polynomial	1*int64		Number of polynomial terms in the polynomial expansions.
Ants_ov_num_precursor_group	1*int64		Number of precursor groups in the calculation.
Ants_ov_total_power	1*float64		Current evaluated total power.

Output fields

Base name	Suffix	Mesh	Type	Units	Explanation	Notes
Ants_of_active_volume		Calculation node	float64	m3	Node active volume (zero for reflector nodes)
Ants_of_boron_concentration		Calculation node	float64	ppm	Local boron concentration.
Ants_of_burnup		Calculation node	float64	MWd/kgU	Local burnup.
Ants_of_coolant_mean_historical_density		Calculation node	float64	kg/m3	Local mean historical coolant density.
Ants_ov_datafield_flux_group_<group>		Datafield	float64	1/(m2s)	Local homogeneous flux.
Ants_ov_datafield_nodal_response	_<resp>	Datafield	float64		Local homogeneous flux times nodal response function.
Ants_of_fission_source_expansion_coeff	_poly_<poly>_group_<group>	Calculation node	float64		Coefficients of polynomial fission source expansion.	Used in transient calculations and transient restarts.
Ants_of_flux		Calculation node	float64	m/s	Integral flux.
Ants_of_flux_expansion_coeff	_poly_<poly>_group_<group>	Calculation node	float64		Coefficients of polynomial flux expansion.	Used in transient calculations and transient restarts.
Ants_of_fuel_assembly_index		Calculation node	int64	unitless	Which fuel assembly does this node belong to?
Ants_of_hm_mass		Calculation node	float64	kg	Local heavy metal mass.
Ants_of_mdep_activity	_region_<region>	Microdepletion	float64	1/s	Local activity of microdepletion nuclides.
Ants_of_mdep_decay_heat	_region_<region>	Microdepletion	float64	W	Local decay heat of microdepletion nuclides.
Ants_of_mdep_number_density	_region_<region>	Microdepletion	float64	1/m3	Local number density of microdepletion nuclides.
Ants_of_mdep_zai	_region_<region>	Microdepletion	float64	unitless	Local ZAI of microdepletion nuclides.
Ants_of_min_eigenvalue_calculated		Calculation node	float64	unitless	The smallest (absolute) local node eigenvalue calculated, before critical node treatments were applied.
Ants_of_min_eigenvalue_used		Calculation node	float64	unitless	The smallest (absolute) local node eigenvalue used, after critical node treatments were applied.
Ants_of_num_mdep_region		Calculation node	int64	unitless	Number of microdepletion regions present in the local node.
Ants_of_num_nuclide	_region_<region>	Microdepletion	int64	unitless	Number of nuclides in each microdepletion region.
Ants_of_number_density_i135		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_np239		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_pm149		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_pu239		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_sm149		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_u238		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_xe135		Calculation node	float64	1/m3	Local number density.
Ants_of_number_density_xe135m		Calculation node	float64	1/m3	Local number density.
Ants_of_outcurrent	_group_<group>_moment_<moment>	Calculation node	float64	1/s	Local node outwards neutron current moments.
Ants_of_power		Calculation node	float64	W	Local node power.
Ants_of_precursor_expansion_coeff	_poly_<poly>_precursor_group_<precgroup>	Calculation node	float64		Coefficients of polynomial precursor number density expansion.	Used in transient calculations and transient restarts.
Ants_of_supernode_active_volume		Input node	float64	m3	Input node active volume (zero for reflector nodes).
Ants_of_supernode_index		Input node	float64	-	Ants internal index of input node.
Ants_of_supernode_nodal_response		Input node	float64		Local evaluated value for the nodal response.
Ants_of_supernode_num_pin		Input node	float64		Number of pins in input node.
Ants_of_supernode_power		Input node	float64	W	Power of input node.
Ants_of_supernode_ppr_burnup		Input node pin	float64	MWd/kgU	Pin burnup at input node.
Ants_of_supernode_ppr_flux	_group_<group>	Input node pin	float64	m/s	Pin integral group flux at input node.
Ants_of_supernode_ppr_hm_mass		Input node pin	float64	kg/m3	Pin heavy metal mass at input node.
Ants_of_supernode_ppr_power		Input node pin	float64	W	Pin power at input node.
Ants_of_supernode_ppr_power	_group_<group>	Input node pin	float64	W	Pin group power at input node.
Ants_of_supernode_ppr_wx		Input node pin	float64	m	Local pin cell x widths.
Ants_of_supernode_ppr_wy		Input node pin	float64	m	Local pin cell y widths
Ants_of_supernode_ppr_x		Input node pin	float64	m	Local pin cell centroid x-coordinates.
Ants_of_supernode_ppr_y		Input node pin	float64	m	Local pin cell centroid y-coordinates.
Ants_of_supernode_volume		Input node	float64	m3	Input node volume
Ants_of_surfaceflux	_group_<group>_moment_<moment>	Calculation node	float64	1/s	Local node surface flux moments.
Ants_of_volume		Calculation node	float64	m3	Node volume.
Ants_of_xs_absorption	_group_<group>	Calculation node	float64	1/m	Local absorption cross section.
Ants_of_xs_beta	_precursor_group_<precgroup>	Calculation node	float64	unitless	Local delayed neutron fraction.
Ants_of_xs_chi_delayed	_group_<group>	Calculation node	float64	unitless	Local delayed fission neutron spectrum.
Ants_of_xs_chi_prompt	_group_<group>	Calculation node	float64	unitless	Local prompt fission neutron spectrum.
Ants_of_xs_chi_total	_group_<group>	Calculation node	float64	unitless	Local total fission neutron spectrum.
Ants_of_xs_diffusion	_group_<group>	Calculation node	float64	m	Local diffusion coefficient.
Ants_of_xs_discontinuityfactor	_group_<group>_moment_<moment>	Calculation node	float64	unitless	Local flux moment discontinuity factor.
Ants_of_xs_fission	_group_<group>	Calculation node	float64	1/m	Local fission cross section.
Ants_of_xs_inversevelocity	_group_<group>	Calculation node	float64	s/m	Local inverse velocity.
Ants_of_xs_kappafission	_group_<group>	Calculation node	float64	J/m	Local fission energy production cross section.
Ants_of_xs_lambda	_precursor_group_<precgroup>	Calculation node	float64	1/s	Local precursor decay constant.
Ants_of_xs_nufission	_group_<group>	Calculation node	float64	1/m	Local fission neutron production cross section.
Ants_of_xs_removal	_group_<group>	Calculation node	float64	1/m	Local removal cross section.
Ants_of_xs_scattering	_group_<fromgroup>_group_<togroup>	Calculation node	float64	1/m	Local group to group scattering cross sections.

Meshes

Ants input and output fields are based on a few different meshes.

Input node pin mesh

A two level mesh where the first level corresponds to the input node mesh, while the second level is a list of the different pins inside the input node.

Calculation node pin mesh

A two level mesh where the first level corresponds to the calculation node mesh, while the second level is a list of the different pins inside the input node.

Microdepletion mesh

A two level mesh where the first level corresponds to the calculation node mesh, while the second level is a list of the different nuclides in the calculation node.

Datafield mesh

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