SuperFINIX input manual

The input of SuperFINIX follows the same syntactic principles of Serpent inputs, i.e. the format of the input file is unrestricted. The file consists of white-space (space, tab or newline) separated words, containing alphanumeric characters(’a-z’, ’A-Z’, ’0-9’, ’.’, ’-’). If special characters or white spaces need to be used within the word (file names, etc.), the entire string must be enclosed within quotes.

The input file is divided into separate data blocks, denoted as cards. The file is processed one card at a time and there are no restrictions regarding the order in which the cards should be organized. The input cards are listed below. Additional options are followed by key word "set". All input cards and options are case-insensitive. Each input card is delimited by the beginning of the next card. It is hence important that none of the parameter strings used within the card coincide with the card identifiers.

The percent-sign ('%') is used to define a comment line. Anything from this character to the end of the line is omitted when the input file is read. The alternative is to use C-style comment sections beginning with "/*" and ending with "*/". Everything between these delimiters is omitted, regardless of the number of newlines or special characters.

This page will contain the whole input syntax of SuperFINIX, with links to more detailed descriptions where needed.

Input cards

NOTE: SuperFINIX command words are in boldface and input parameters entered by the user in CAPITAL ITALIC. Optional input parameters are enclosed in [ square brackets ], and when the number of values is not fixed, the remaining values are marked with three dots (...).

lat (regular lattice definition)

lat UNI TYPE X0 Y0 NX NY PITCH UNI1 UNI2 ...

Defines a finite two-dimensional lattice in xy-plane with square or X- or Y-type hexagonal elements. The lattice is infinite in z-direction. Input values:

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Lattice type 1 indexing example for N_X = N_Y = 3.

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Lattice type 2 indexing example for N_X = N_Y = 3.

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Lattice type 3 indexing example for N_X = N_Y = 3.

UNI	: universe name of the lattice
TYPE	: lattice type
X0	: x-coordinate of the lattice origin (origin is in the center of the lattice).
Y0	: y-coordinate of the lattice origin (origin is in the center of the lattice).
NX	: number of lattice elements in x-direction
NY	: number of lattice elements in y-direction
PITCH	: lattice pitch
UNIn	: list of universes filling the lattice positions

Possible lattice types are:

Type	Description
1	Square lattice
2	X-type hexagonal lattice
3	Y-type hexagonal lattice

Notes:

• Number of universes in list of universes must be N_X × N_Y.
• For square lattices the x coordinate increases from left to right and the y coordinate increases from top to bottom, so the first N_X values in the list of universes create the bottommost (minimum y) row from minimum x to maximum x and the last N_X values in the list of universes create the topmost (maximum y) values. Example of the indexing is provided in the attached figure.
• The line breaks usually present in the list of universes are only used to help visualizing the universe order for the user. SuperFINIX ignores them when processing the list of universes.
• The input of X- and Y-type hexagonal lattices is similar to each other, only the directions of the x- and y-axis change. The axis directions can be checked by using the geometry plotter. Examples of the indexing are provided in the attached figures.

rodtype (rod type definition)

rodtype NAME ROD_NAME OPTIONS_NAME SCENARIO_NAME [ multiplicity N ]
            [ rgb R G B ]

Defines the variations invoked for a branch in the automated burnup sequence.

Mandatory information:

NAME	: Name identifying this rod type in the rest of the SuperFINIX input.
ROD_NAME	: Name of the FINIX rod block to use for defining the basic fuel rod properties for this rod type.
OPTIONS_NAME	: Name of the FINIX options block to use for defining the general options for this rod type.
SCENARIO_NAME	: Name of the FINIX scenario block to use for defining the scenario for this rod type.

Optional cards:

multiplicity: Multiplicity for this rod type, which is used to divide the values of incoming power before it is passed to a FINIX solver.

N	: Optional multiplicity for the rod, i.e. this rod type represents N fuel rods and the input power for this rod type will be divided by N before being given to FINIX.

rgb: Rod type color for geometry plots

R	: Value for the red channel of geometry plots (between 0 and 255)
G	: Value for the green channel of geometry plots (between 0 and 255)
B	: Value for the blue channel of geometry plots (between 0 and 255)

Notes:

• The ROD_NAME, OPTIONS_NAME and SCENARIO_NAME must match block names in the FINIX rod library, options library and scenario library respectively.

include (read another input file)

include FILE

Reads another input file. Input values:

FILE	: name of the input file

Notes:

• The include card can be used to simplify the structure of complicated inputs.
• The input parser starts reading and processing the new file from the point where the input card is placed. Processing of the original file continues after the new file is completed.
• The included file must contain complete input cards and options, it cannot be used to read the values of another card.

plot (geometry plot definition)

plot TYPE XPIX YPIX [ POS MIN1 MAX1 MIN2 MAX2 ]

Produces a png-format geometry plot. Input values:

TYPE	: defines the plot type (orientation and plotting of boundaries)
XPIX	: horizontal image size in pixels
YPIX	: vertical image size in pixels
POS	: position of plot plane
MIN1	: minimum horizontal coordinate of plotted region
MAX1	: maximum horizontal coordinate of plotted region
MIN2	: minimum vertical coordinate of plotted region
MAX2	: maximum vertical coordinate of plotted region

Notes:

• The TYPE parameter consists of one or two concatenated values ('AB'):
  1. The first value ('A') defines the plot plane (1 = yz, 2 = xz, 3 = xy).
  2. The second value ('B') defines which boundaries are plotted (0 = no boundaries, 1 = cell boundaries, 2 = material boundaries, 3 = both). If the second value in is not provided, material boundaries are plotted.
• Each material plotted with different color. The colors are sampled randomly, unless defined using the rgb entry in the rodtype card.
• Empty lattice positions are plotted in black and special colors are used to plot geometry errors (red = overlap, green = undefined region).
• The position parameter defines the location of the plot plane on the axis perpendicular to it (e.g. z-coordinate for xy-type plot).
• The minimum and maximum coordinates define the boundaries of the plotted region (e.g. minimum and maximum x- and y-coordinates for xy-type plot). If these coordinates are not provided, the plot is extended to the maximum dimensions of the geometry.
• The relative dimensions of image size in pixels should match that of the plotted region. Otherwise the image gets distorted.
• Geometry plotter requires compiling the source code with GD Graphics libraries.
• Geometry plot produced by the nth plot-card is written in file [input]_geom[n].png.

Input options

Input options are used to set various calculation parameters that are not included in the main input cards. Each option is identified by key word "set". Optional values are enclosed within square brackets.

set binaryrestart

set binaryrestart OPT

Use binary restart files for FINIX and internal memory restarts where possible instead of writing plaintext restart files.

OPT	: option (0/no/1/yes)

Notes:

• Default value is yes.
• With binary restart files on, much of the intermediate storage of restarts is handled in program memory.

set burnupmaxstep

set burnupmaxstep STEPSIZE

Maximum step size for FINIX time-integration in burnup problems before the step is divided into internal sub-steps.

STEPSIZE

: Length of step in seconds.

Notes:

• Default value is 10 years (60.0*60.0*24*365*10 seconds), meaning that the steps are not subdivided inside SuperFINIX.

set finalrestart

set finalrestart OPT

Should restart files be automatically written for each rod at the end of the calculation?

OPT	: option (0/no/1/yes)

Notes:

• Default value is yes.

set finixbc

set finixbc BC

Sets the boundary condition to use for the FINIX thermal solution inside rods.

BC	: Integer value for the boundary coefficient. Allowed values: 0 (Fixed clad outer temperature) and 2 (heat transfer coefficient at cladding surface and coolant bulk temperature given).

Notes:

• Default value is 0, fixed clad outer temperature.

set inrmesh

set inrmesh NR RMIN RMAX
set inrmesh -NR R0 R1 ... RNR

Defines the global input radial meshing used in all rods for the input radial power field. If a radially flat input power distribution is to be used, one radial zone with limits corresponding to the pellet cold inner and outer radii should be used. Either equally or arbitrarily spaced based on the sign of the first parameter.

NR	: Number of radial zones.
RMIN	: Minimum radial coordinate (cm).
RMIN	: Maximum radial coordinate (cm).
Ri	: Arbitrarily spaced radial zone boundary (cm).

Notes:

• See separate page for information on how the radial power distribution is transferred from SuperFINIX to FINIX.

set mingaphtc

set mingaphtc HTC

Sets minimum allowed gas gap heat transfer coefficient during FINIX internal secant iteration for gas gap heat transfer coefficient. Too low values encountered during the iteration can lead to momentary high pellet temperatures and a breakdown of the solvers.

HTC	: Lower boundary for heat transfer coefficient in secant iteration (W/m2).

Notes:

• Default value is 300 W/m².

set optionsfile

set optionsfile FNAME

Sets path to the file containing FINIX options-definitions.

FNAME

: Path to file.

Notes:

• See section 8.7 in the FINIX manual for information on the FINIX input files.

set outrmesh

set outrmesh NR RMIN RMAX
set outrmesh -NR R0 R1 ... RNR

Defines the global output radial meshing used in all rods for the output radial temperature field. Either equally or arbitrarily spaced based on the sign of the first parameter.

NR	: Number of radial zones.
RMIN	: Minimum radial coordinate (cm).
RMIN	: Maximum radial coordinate (cm).
Ri	: Arbitrarily spaced radial zone boundary (cm).

Notes:

• See separate page for information on the radial averaging of FINIX temperatures to this radial mesh.

set pport

set pport PORT

The port to connect to in Cerberus driven calculations.

PORT	: Port number.

Notes:

• It is generally simpler to use the -port command line parameter when executing SuperFINIX through Cerberus.
• Can not be used at the same time with the -port command line parameter.

set rodfile

set rodfile FNAME

Sets path to the file containing FINIX rod-definitions.

FNAME

: Path to file.

Notes:

• See section 8.7 in the FINIX manual for information on the FINIX input files.

set scenariofile

set scenariofile FNAME

Sets path to the file containing FINIX scenario-definitions.

FNAME

: Path to file.

Notes:

• See section 8.7 in the FINIX manual for information on the FINIX input files.

set steadymaxstep

set steadymaxstep STEPSIZE

Maximum step size for FINIX time-integration in the evaluation of a "steady state" fuel behaviour solution before the step is divided into internal sub-steps.

STEPSIZE

: Length of step in seconds.

Notes:

• Default value is 1 hour (60.0*60.00 seconds).

set steadyrelaxtime

set steadyrelaxtime TIME

Time used for the evaluation of "steady state" fuel behaviour solution. Assumption is that after changes to the fuel rod boundary conditions (power, thermal boundary condition, ...) the fuel rod behaviour will relax into a new steady state after a short TIME.

TIME	: Time (in seconds) to allow for relaxation of fuel rod behaviour after changes to boundary conditions.

Notes:

• Default value is 1 hour (60.0*60.0 seconds).

set toplattice

set toplattice LAT

Sets the top level lattice that is used as the basis for the geometry.

LAT	: Name of the top level lattice.

Notes:

• The top level lattice forms the basis for the geometry and can contain fuel rods or other lattices as its elements.

set transientmaxstep

set transientmaxstep STEPSIZE

Maximum step size for FINIX time-integration in transient problems before the step is divided into internal sub-steps.

STEPSIZE

: Length of step in seconds.

Notes:

• Default value is 1 hour (60.0*60.0 seconds).

set zmesh

set zmesh NZ ZMIN ZMAX
set zmesh -NZ Z0 Z1 ... ZNZ

Defines the global axial meshing used for all rods as well as all input and output fields. Either equally or arbitrarily spaced based on the sign of the first parameter.

NZ	: Number of axial zones.
ZMIN	: Minimum axial coordinate (cm).
ZMIN	: Maximum axial coordinate (cm).
Zi	: Arbitrarily spaced axial zone boundary (cm).

Notes:

• At the moment, all assemblies and rods will use the same axial meshing.
• The number of axial zones here needs to match the one given in the FINIX options block defined for each rodtype.