Difference between revisions of "Input syntax manual"
(→set confi) |
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*The importance mesh is printed in file [input].msh. | *The importance mesh is printed in file [input].msh. | ||
*Importance (weight window) meshes are read using the [[#wwin (weight window mesh definition)|wwin card]]. | *Importance (weight window) meshes are read using the [[#wwin (weight window mesh definition)|wwin card]]. | ||
− | *This capability is | + | *This capability is still <u>very much under development</u>. The input syntax may be revised at some point. |
=== wwin (weight window mesh definition) === | === wwin (weight window mesh definition) === |
Revision as of 15:24, 23 September 2016
Serpent has no interactive user interface. All communication between the code and the user is handled through one or several input files and various output files.
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 (note to developers: make it so). 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. Unlike Serpent 1, hashtag ('#') can no longer be used to mark comment lines in Serpent 2 input. 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 Serpent 2, with links to more detailed descriptions where needed. For reference see also the Serpent 1 input manual.[1]
Contents
- 1 Input cards
- 1.1 branch (branch definition)
- 1.2 cell (cell definition)
- 1.3 coef (coefficient matrix definition)
- 1.4 det (detector definition)
- 1.5 div (divisor definition)
- 1.6 ftrans (fill transformation)
- 1.7 ifc (interface file)
- 1.8 include (read another input file)
- 1.9 lat (regular lattice definition)
- 1.10 mat (material definition)
- 1.11 mesh (mesh plot definition)
- 1.12 pin (pin geometry definition)
- 1.13 plot (geometry plot definition)
- 1.14 solid (irregular 3D geometry definition)
- 1.15 src (source definition)
- 1.16 strans (surface transformation)
- 1.17 surf (surface definition)
- 1.18 tme (time binning definition)
- 1.19 trans (transformations)
- 1.20 utrans (universe transformation)
- 1.21 wwgen (response matrix based importance map solver)
- 1.22 wwin (weight window mesh definition)
- 2 Input options
- 2.1 set acelib
- 2.2 set adf
- 2.3 set arr
- 2.4 set bc
- 2.5 set blockdt
- 2.6 set ccmaxiter
- 2.7 set ccmaxpop
- 2.8 set coefpara
- 2.9 set comfile
- 2.10 set confi
- 2.11 set declib
- 2.12 set delnu
- 2.13 set depout
- 2.14 set dfsol
- 2.15 set dynsrc
- 2.16 set dt
- 2.17 set entr
- 2.18 set forcedt
- 2.19 set fsp
- 2.20 set fum
- 2.21 set gbuf
- 2.22 set gcu
- 2.23 set gcut
- 2.24 set his
- 2.25 set impl
- 2.26 set inventory
- 2.27 set mcvol
- 2.28 set micro
- 2.29 set memfrac
- 2.30 set minxs
- 2.31 set mvol
- 2.32 set nbuf
- 2.33 set nfg
- 2.34 set nfylib
- 2.35 set nphys
- 2.36 set nps
- 2.37 set outp
- 2.38 set poi
- 2.39 set pop
- 2.40 set ppid
- 2.41 set ppw
- 2.42 set relfactor
- 2.43 set rfr
- 2.44 set rfw
- 2.45 set root
- 2.46 set savesrc
- 2.47 set seed
- 2.48 set spd
- 2.49 set sfylib
- 2.50 set title
- 2.51 set tcut
- 2.52 set tpa
- 2.53 set ures
- 2.54 set usym
- 3 References
Input cards
NOTE: Serpent 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 (...).
branch (branch definition)
branch NAME [ repm MAT1 MAT2 ] [ repu UNI1 UNI2 ] [ stp MAT DENS TEMP THERM1 SABL1 SABH1 THERM2 SABL2 SABH2 ... ] [ tra TGT TRANS ] [ var VNAME VAL ]
Defines the variations invoked for a branch in the automated burnup sequence. Input values:
NAME | : branch name |
MAT1 | : name of the replaced material |
MAT2 | : name of the replacing material |
UNI1 | : name of the replaced universe |
UNI2 | : name of the replacing universe |
MAT | : name of the material for which density and temperature are adjusted |
DENS | : material density after adjustment (positive entries for atomic, negative entries for mass densities, or "sum" to use the sum of the constituent nuclide densities) |
TEMP | : material temperature after adjustment, or -1 if no adjustment in temperature |
THERMn | : n:th thermal scattering data associated with the material |
SABLn | : name of the n:th S() library for temperature below the given value |
SABHn | : name of the n:th S() library for temperature above the given value |
TGT | : target universe, surface or cell |
TRANS | : applied transformation |
VNAME | : variable name |
VAL | : variable value |
Notes:
- The branch name identifies the branch in the coefficient matrix of the coef card
- The input parameters consist of a number variations, which are invoked when the branch is applied. A single branch card may inclued one or several variations.
- The repm variation can be used to replace one material with another, for example, to change coolant boron concentration.
- The repu variation can be used to replace one universe with another, for example, to replace empty control rod guide tubes with rodded tubes for control rod insertion in 2D geometries.
- The stp variation can be used to change material density and temperature. The adjustment is made using the built-in Doppler-broadening preprocessor routine and tabular interpolation for S() thermal scattering data.
- The last three parameters of the stp entry are provided only if the material has thermal scattering libraries attached to it (see the therm card).
- The tra variation can be used to move or rotate different parts of the geometry, for example, to adjust the position of control rods in 3D geometries.
- Variables can be used to pass information into output file, which may be convenient for the post-processing of the data.
- The branch card is used together with the coef card.
- For more information, see detailed description on the automated burnup sequence.
cell (cell definition)
cell NAME UNI0 MAT [ SURF1 SURF2 ... ]
Defines a material cell. Input values:
NAME | : cell name |
UNI0 | : universe where the cell belongs to |
MAT | : material that fills the cell |
SURFn | : surface list |
cell NAME UNI0 fill UNI1 [ SURF1 SURF2 ... ]
Defines a filled cell. Input values:
NAME | : cell name |
UNI0 | : universe where the cell belongs to |
UNI1 | : universe that fills the cell |
SURFn | : surface list |
cell NAME UNI0 outside [ SURF1 SURF2 ... ]
Defines an outside cell. Input values:
NAME | : cell name |
UNI0 | : universe where the cell belongs to |
SURFn | : surface list |
Notes:
- There are three types of cells: material cells, filled cells and outside cells. Filled cells are identified by providing the key word fill, followed by the universe filling the cell. If the key word is missing, the third entry is interpreted as the material filling the cell. Outside cells are identified by replacing the material name with key word outside.
- Void cells can be defined by setting the material name to "void"
- When the geometry is set up, the root universe must always be defined. By default the root universe is named "0", and it can be changed with the set root option.
- Outside cells are used to define the part of the geometry that does not belong to the model. When the particle enters an outside cell, boundary conditions are applied. It is important that the geometry model is non-re-entrant when vacuum boundary conditions are used.
- Outside cells are allowed only in the root universe. It is important that all space outside the model is defined.
- The surface list defines the boundaries of the cell by listing the surface names (as provided in the surface card), together with the operator identifiers (nothing for intersection, ":" for union, "-" for complement and "#" for cell complement).
- For more information, see detailed description on the universe-based geometry type in Serpent.
coef (coefficient matrix definition)
coef NBU [ BU1 BU2 ... ] [ NBR1 BR1,1 BR1,2 ... ] [ NBR2 BR2,1 BR2,2 ... ] ...
Defines the coefficient matrix for the automated burnup sequence. Input values:
NBU | : number of burnup points |
BUn | : burnup steps at which the branches are invoked |
NBRm | : number branches in the m:th dimension of the burnup matrix |
BRm,i | : name of the i:th branch in the m:th dimension |
Notes:
- The coef card creates a multi-dimensional coefficient matrix (of size NBR1 NBR2 NBR3 ... ). The automated burnup sequence performs a restart for each of the listed burnup points, and loops over the branch combinations defined by the coefficient matrix.
- The coef card is used together with the branch card
- For more information, see detailed description on automated burnup sequence.
det (detector definition)
det NAME [ PARTICLE] [ dr MT MAT] [ dv VOL] [ dc CELL] [ du UNI] [ dm MAT] [ dl LAT] [ dx XMIN XMAX NX] [ dy YMIN YMAX NY] [ dz ZMIN ZMAX NZ] [ dn MESHTYPE MIN0 MAX0 N0 MIN1 MAX1 N1 MIN2 MAX2 N2] [ dh HEXTYPE X0 Y0 PITCH NX NY ZMIN ZMAX NZ] [ de EGRID] [ di TBIN] [ ds SURF DIR] [ dir COSX COSY COSZ] [ dtl SURF] [ df FILE FRACTION] [ dt TYPE PARAM] [ da DET] [ dh LOGICAL] [ dumsh UNI NCELL CELL0 BIN0 CELL1 BIN1 ...]
Detector definition. Input values:
dn | : Curvilinear mesh detector |
MESHTYPE | : Type of curvilinear mesh. 1 = cylindrical (dimensions r, phi, z). 2 = spherical (dimensions r, phi, theta) |
MINn | : Minimum value of coordinate n for the mesh division. |
MAXn | : Maximum value of coordinate n for the mesh division. |
Nn | : Number of bins in the n coordinate direction (the division will be equal r, not equal volume). |
div (divisor definition)
div MAT [ sep LVL ] [ subx NX XMIN XMAX ] [ suby NY YMIN YMAX ] [ subz NZ ZMIN ZMAX ] [ subr NR RMIN RMAX ] [ subs NS S0 ]
Divides a material into a number of sub-zones. Input values:
MAT | : name of the divided material |
LVL | : geometry level at which the cell-wise division takes place (0 = no division, 1 = last level, 2 = 2nd last level, etc.) |
NX | : number of x-zones |
XMIN | : minimum x-coordinate (cm) |
XMAX | : maximum x-coordinate (cm) |
NY | : number of y-zones |
YMIN | : minimum y-coordinate (cm) |
YMAX | : maximum y-coordinate (cm) |
NZ | : number of z-zones |
ZMIN | : minimum z-coordinate (cm) |
ZMAX | : maximum z-coordinate (cm) |
NR | : number of radial zones |
RMIN | : minimum radial coordinate (cm) |
RMAX | : maximum radial coordinate (cm) |
NZ | : number of angular sectors |
S0 | : zero position of angular division (degrees) |
Notes:
- The automated divisor feature can be used to sub-divide burnable materials into depletion zones, but the use is not limited to burnup mode.
- The spatial sub-division is based on either Cartesian or cylindrical mesh.
- Volumes of the divided materials must be set manually (see detailed description on the definition of material volumes).
- Using automated instead of manual depletion zone division saves memory, which may become significant in very large burnup calculation problems (see detailed description on memory usage).
- For more information, see detailed description on automated depletion zone division.
ftrans (fill transformation)
See transformations.
ifc (interface file)
ifc FILE
Links a multi-physics interface file to be used with the current input. Input values:
FILE | : path to the multi-physics interface file |
Notes:
- See also Coupled multi-physics calculations.
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 and options, it cannot be used to read the values of another card.
lat (regular lattice definition)
mat (material definition)
mesh (mesh plot definition)
pin (pin geometry definition)
plot (geometry plot definition)
plot TYPE XPIX YPIX [ POS MIN1 MAX1 MIN2 MAX2 ]
plot TYPE Fmin Fmax E 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 |
Fmin | : minimum importance for importance map plots |
Fmax | : maximum importance for importance map plots |
E | : particle energy for importance map plots |
Notes:
- The type parameter consists of one or two concatenated values ('AB'):
- The first value ('A') defines the plot plane (1 = yz, 2 = xz, 3 = xy).
- 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.
- Importance maps read using the wwin card can be plotted on top of the geometry by setting the second value ('B') of the type parameter to 4 (linear color scheme) or 5 (logarithmic color scheme). The input parameters then also include the minimum and maximum importance and the particle energy.
- Each material plotted with different color. The colors are sampled randomly, unless defined using the rgb entry in the material card.
- Void is 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.
- Command line parameter '-plot' stops the execution after the geometry plots are prodused. Option '-qp' invokes a quick plot mode, which does not check for overlaps.
- See practical examples.
- Note to developers: particle type should be included as an input parameter in importance map plots.
solid (irregular 3D geometry definition)
solid 1 UNI BGUNI MESH_SPLIT MESH_DIM SZ1 SZ2 ... SZMESH_DIM POINTS_FILE FACES_FILE OWNER_FILE NEIGHBOUR_FILE MATERIALS_FILE
Creates an unstructured mesh-based geometry universe. Input values are:
UNI | : universe name for the irregular geometry |
BGUNI | : name of the background universe filling all undefined space |
MESH_SPLIT | : Splitting criterion for the adaptive search mesh (maximum number of geometry cells in search mesh cell) |
MESH_DIM | : number of levels in the adaptive search mesh |
SZi | : Size of the search mesh at level i |
POINTS_FILE | : Path to the unstructured mesh points file |
FACES_FILE | : Path to the unstructured mesh faces file |
OWNER_FILE | : Path to the unstructured mesh owner file |
NEIGHBOUR_FILE | : Path to the unstructured mesh neighbour file |
MATERIALS_FILE | : Path to the unstructured mesh materials file |
solid 2 UNI BGUNI MESH_SPLIT MESH_DIM SZ1 SZ2 ... SZMESH_DIM MODE R0 body BODY1 CELL1 MAT1 file BODY1 FILE1 SCALE1 X1 Y1 Z1 file BODY1 FILE2 SCALE2 X2 Y2 Z2 ... body BODY2 CELL2 MAT2 file BODY2 FILE3 SCALE3 X3 Y3 Z3 file BODY2 FILE4 SCALE4 X4 Y4 Z4 ...
Creates an STL-based geometry universe. Input values are:
UNI | : universe name for the irregular geometry |
BGUNI | : name of the background universe filling all undefined space |
MESH_SPLIT | : Splitting criterion for the adaptive search mesh (maximum number of geometry cells in search mesh cell) |
MESH_DIM | : number of levels in the adaptive search mesh |
SZi | : Size of the search mesh at level i |
MODE | : Mode for handling the triangulated geometry (1 = "fast", 2 = "safe"). |
R0 | : Radius inside which two points of the STL-geometry are joined into one. |
BODYi | : Name of solid body i |
CELLi | : Name of geometry cell i linked with body i |
MATi | : Material filling cell i |
FILEi | : Path to a file containing an STL solid model, multiple files can be linked to one body |
SCALEi | : Scaling factor for the STL model in FILEi |
Xi | : Shift in x-direction to the STL model in FILEi |
Yi | : Shift in y-direction to the STL model in FILEi |
Zi | : Shift in z-direction to the STL model in FILEi |
solid 3 INTERFACE_FILE
Creates an unstructured mesh-based geometry universe with unstructured mesh-based temperature and/or density distributions. Input values are:
INTERFACE_FILE | : Path to the interface file containing the rest of the parameters |
src (source definition)
strans (surface transformation)
See transformations.
surf (surface definition)
surf NAME TYPE [ PARAM1 PARAM2 ... ]
Defines a surface. Input values:
NAME | : is the surface name |
TYPE | : is the surface type |
PARAMn | : are the surface parameters |
Notes:
- The name is used to identify the surface, for example, in the cell card.
- See separate description on surface types.
- Surfaces can be moved and rotated using transformations.
tme (time binning definition)
tme NAME 1 NB LIM1 LIM2 ...
tme NAME 2 NB Tmin Tmax
tme NAME 3 NB Tmin Tmax
Defines a time binning structure. The second entry sets the binning type (1 = arbitrary, 2 = uniform, 3 = log-uniform). Remaining values:
NAME | : name of the time binning |
NB | : number of bins |
LIMn | : upper time boundary in arbitrary binning |
Tmin | : minimum time boundary in uniform or log-uniform binning |
Tmax | : maximum time boundary in uniform or log-uniform binning |
Notes:
- The entered values are in seconds
- Time binning is used with detectors and dynamic simulation mode.
trans (transformations)
trans TYPE UNIT LVL
trans TYPE UNIT X Y Z
trans TYPE UNIT X Y Z θx θy θz
trans TYPE UNIT X Y Z α1 α2 α3 α4 α5 α6 α7 α8 α9
Defines surface, universe or fill transformation. Input values:
TYPE | : type of transformation (S = surface transformation, F = fill transformation, U = universe transformation) |
UNIT | : surface, cell or universe name to which the transformation is applied |
LVL | : level number in universe level transformation |
X,Y,Z | : translation vector |
θx θy θz | : rotation angles with respect to x-, y- and z-axes (in degrees) |
α1 ... α9 | : coefficients of the rotation matrix |
Notes:
- Fill transformation is applied in the universe filling the given cell.
- Level transformation is a special type of universe transformation, in which the coordinates in the given universe are obtained relative to geometry level LVL.
- Rotations are applied before translations.
- Rotations can be defined either by providing the three angles with respect to the three coordinate axes, or by defining the rotation matrix. In the second case Serpent applies vector multiplication where and are the position vectors before and after the operation and coefficients α1 ... α9 define the 3 by 3 matrix .
- To preserve backwards compatibility, input parameters "strans", "utrans" and "ftrans" without the following type identifier are also accepted for defining surface, universe and fill transformations, respectively. To preserve compatibility with Serpent 1, parameter "trans" without type identifier defines a universe transformation.
utrans (universe transformation)
See transformations.
wwgen (response matrix based importance map solver)
wwgen NAME NI F ERG MSH MIN1 MAX1 SZ1 MIN2 MAX2 SZ2 MIN3 MAX3 SZ3 DET1 w1 [ DET2 w2 ... ]
Defines the parameters for importance map calculation. Input values:
NAME | : a unique name to identify the calculation |
NI | : maximum number of iterations |
F | : normalization factor / weighing flag |
ERG | : energy group structure (or -1 if no energy dependence is included) |
MSH | : mesh type (1 = Cartesian, 2 = Cylindrical) |
MINn | : minimum mesh boundary (n:th coordinate) |
MAXn | : maximum mesh boundary (n:th coordinate) |
SZn | : number of mesh cells (n:th coordinate) |
DETi | : detectors used as target response functions |
wi | : weight factors for detector scores |
Notes:
- Multiple energy groups not yet supported (input value must be set to -1).
- The importances are normalized in such way that the maximum importance in cells with source points is set to F.
- If the the normalization factor is given with a negative sign, inverse detector scores are used in the importance calculation.
- The coordinate axes 1, 2 and 3 in Cartesian mesh refer to (x,y,z) and in cylindrical mesh to (r,θ,z), with θ given in degrees.
- The mesh must be defined slightly larger than the geometry (the mesh boundaries should not coincide with the geometry boundaries).
- Source points located on mesh cell boundaries cause fatal errors.
- Works only with external source simulations.
- May not work if source distribution is biased with weight.
- The importance mesh is printed in file [input].msh.
- Importance (weight window) meshes are read using the wwin card.
- This capability is still very much under development. The input syntax may be revised at some point.
wwin (weight window mesh definition)
wwin NAME [ wf FILE FMT ] [ wn F X Y Z E ] [ wx C G ]
Defines a weight window mesh for variance reduction. Input values:
NAME | : a unique name to identify the mesh |
FILE | : file path and name of the importance mesh file |
FMT | : file format (1 = mesh produced by Serpent importance map generator, 2 = MCNP weight window mesh file) |
F | : importance for renormalization |
X,Y,Z | : coordinates of point used for renormalization |
E | : energy used for renormalization |
C | : constant multiplier for adjusting importances |
G | : exponential for adjusting importances |
Notes:
- By default the importance map is read from the mesh file and used as-is, the additional options are provided for adjustments.
- The importances can be renormalized using the wn option by fixing the value at a given position and energy.
- The importances can be adjusted using the wx option by constant multiplier C and exponential factor G such that .
- Only works in external source simulation mode.
- No source biasing is currently applied.
- Importance (weight window) meshes can be generated by running the response matrix based solver.
- Importance maps can be visualized using the geometry plotter.
- This capability is available in version 2.1.27 still very much under development. The input syntax may be revised at some point.
Input options
Input options are used to set various calculation parameters that are not included in the main input cars. Each option is identified by key word "set". Optional values are enclosed within square brackets.
set acelib
set acelib LIB1 [ LIB2 LIB3 ... ]
Sets the cross section directory file paths. Input values:
LIBn | : file paths to directory files |
Notes:
- If the file path contains special characters it is advised to enclose it within quotes.
- A default directory path can be set by defining environment variable SERPENT_DATA. The code looks for cross section directory files in this path if not found at the absolute.
set adf
set adf UNI SURF SYM
Sets parameters for the calculation of assembly discontinuity factors. Input values:
UNI | : universe where spatial homogenization is performed |
SURF | : surface enclosing the universe |
SYM | : symmetry option (see separate list) |
Notes:
- The surface enclosing the universe can be super-imposed (i.e. not part of the geometry definition), but it must enclose the entire universe.
- When the universe is surrounded by zero net-current (reflective) boundary conditions, the ADF's are calculated as the ratios of surface- and volume-averaged heterogeneous flux.
- When the net current is non-zero, the calculation is based on the ratio of surface-averaged homogeneous and heterogeneous flux. The homogeneous flux is obtained from a built-in diffusion flux solver.
- Calculation parameters for the diffusion flux solver can be set using the set dfsol option.
- Calculation of ADF's is currently allowed only for planes and infinite square and hexagonal prisms.
- Symmetry options are used to average out the statistical variation in the ADF's, which might otherwise lead to systematic errors in core calculations. It is important that the options are used only when the geometry has the corresponding symmetry.
- See separate description of output parameters.
set arr
set arr MODEN [ MODEG ]
Sets analog reaction rate calculation on or off. Input values:
MODEN | : mode for neutrons (0 = no reactions included, 1 = include only reactions that affect neutron balance, 2 = include all reactions) |
MODEG | : mode for photons (0 = no reactions included, 1 = include all reactions) |
Notes:
- Analog reaction rates are calculated by counting sampled events and printed in a separate output file.
- See detailed description on the reaction rate output file.
set bc
set bc MODE
Sets the boundary conditions for all outer boundaries of the geometry. Input values:
MODE | : boundary type (1 = vacuum, 2 = reflective, 3 = periodic) |
set bc MODE ALB
Sets the boundary conditions with albedo for all outer boundaries of the geometry. Input values:
MODE | : boundary type (1 = vacuum, 2 = reflective, 3 = periodic) |
ALB | : albedo |
set bc MODEX MODEY MODEZ
Sets the boundary conditions separately for x-, y- and z-directions. Input values:
MODEX | : boundary type in x-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
MODEY | : boundary type in y-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
MODEZ | : boundary type in z-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
set bc MODEX MODEY MODEZ ALB
Sets the boundary conditions with albedo separately for x-, y- and z-directions. Input values:
MODEX | : boundary type in x-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
MODEY | : boundary type in y-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
MODEZ | : boundary type in z-direction (1 = vacuum, 2 = reflective, 3 = periodic) |
ALB | : albedo |
Notes:
- The boundary conditions can be set either for all directions at once (single parameter) or x-, y- and z-directions separately (three parameters). Albedos are provided by adding one more parameter in the list.
- The default boundary condition is vacuum (= 1) in all directions.
- Albedo boundary conditions are invoked by multiplying the particle weight with factor ALB each time a reflective or periodic boundary is hit.
- Repeated boundary conditions (reflective or periodic) are based on universe transformations, which limits outer boundary to surfaces that form regular lattices (square and hexagonal prisms, rectangles, cubes and cuboids).
- Repeated boundary conditions are applied on the first surface of outside cells (see definition of outside cells in the cell card)
- For symmetry purposes Serpent provides the universe symmetry option.
- For more information, see detailed description on boundary conditions.
set blockdt
set blockdt MAT1 MAT2 ...
Defines the list of materials where delta-tracking is never used. Input values:
MATn | : material names |
Notes:
- This option is used to override selection of tracking mode based on the probability threshold (see set dt) in individual materials.
- Use of delta-tracking can be forced in individual materials using set forcedt.
- For more information on tracking modes, see the detailed description on delta- and surface-tracking.
- Note to developers: should have different lists for neutrons and photons?
set ccmaxiter
set ccmaxiter NITER
Sets the maximum number of coupled calculation iterations. Input values:
NITER | : number of iterations. |
Notes:
- Default maximum number of iterations is 1 (no iteration).
- The iteration is stopped when either the maximum number of iterations or the maximum active neutron population (set with set ccmaxpop) has been simulated.
- See Coupled multi-physics calculations for further information.
set ccmaxpop
set ccmaxpop CPOP
Sets the maximum total live population to simulate in a coupled calculation. Input values:
CPOP | : total active population to simulate. |
Notes:
- Default maximum population is INFTY/1e6.
- The iteration is stopped when either the maximum number of iterations (set with set ccmaxiter) or the maximum active neutron population has been simulated.
- Only the population simulated during active cycles is included in this amount.
- This is mostly useful if the neutron population per iteration is not constant.
- See Coupled multi-physics calculations for further information.
set coefpara
set coefpara FMT [ PARAM1 PARAM2 ... ]
Defines the parameters included in the separate group constant output file. Input values:
FMT | : output format, currently used for including or excluding statistical errors (0 = not included, 1 = included) |
PARAMn | : list of parameters or detectors included in the file |
Notes:
- The group constant output file "<input>.coe" is produced when the automated burnup sequence is invoked.
- The available parameters are listed under homogenized group constants in the description of the _res.m output file.
- Detectors are identified by the name assigned to them in the detector card.
set comfile
set comfile INFILE OUTFILE
Defines the communication files used in the file-based coupled calculation communications. Input values:
INFILE | : Path to inwards communication file (signals to Serpent). |
OUTFILE | : Path to outwards communication file (signals fomr Serpent). |
Notes:
- Setting up a communication mode will enable the coupled calculation mode.
- For more information see: External coupling
set confi
set confi OPT
Sets confidentiality flag on or off. Input values:
OPT | : option to set confidentiality flag on (1/yes) or off (0/no) |
Notes:
- This option can be used to label calculations as confidential. If the option is set, text "(CONFIDENTIAL)" is printed in the run-time output next to the calculation title and the value of variable CONFIDENTIAL_DATA in the [input]_res.m output file is set to 1.
set declib
set declib LIB1 [ LIB2 LIB3 ... ]
Sets the decay data library file paths. Input values:
LIBn | : library file paths |
Notes:
- Decay libraries are standard ENDF format files containing decay data.
- If the file path contains special characters it is advised to enclose it within quotes.
- A default directory path can be set by defining environment variable SERPENT_DATA. The code looks for decay data files in this path if not found at the absolute.
set delnu
set delnu OPT
Sets delayed neutron emission on or off. Input values:
OPT | : option to switch delayed neutron emission on (1/yes) or off (0/no) |
Notes:
- Delayed neutron emission is on by default in neutron criticality source and off by default in external source simulation mode.
- See separate description of physics options in Serpent for differences to other codes.
set depout
set depout MODE
Controls which burnable material compositions are printed into the _dep.m output file in case of divided materials. Input values:
MODE | : value indicating, which materials to output to the _dep.m file (1 = only partials, 2 = only parents, 3 = both) |
Notes:
- Default is 2 (only parents)
set dfsol
set dfsol MODE [ NP ]
Options for homogeneous diffusion flux solver. Input values:
MODE | : boundary conditions for solver (1 = include net currents at boundary surfaces and corners, 2 = include only surface currents) |
NP | : number of points for trapezoidal integration for homogeneous flux |
Notes:
- This input option is used to control how the deterministic diffusion flux solver used to obtain assembly discontinuity factors (set adf) and pin power distributions (set ppw) is run
- Default mode is 1 (include both surfaces and corners in solution)
- Default number of points for trapezoidal integration is 100
- See also separate description of the built-in diffusion flux solver.
set dynsrc
set dynsrc PATH [ MODE ]
Links previously generated steady state source distributions to be used in a transient simulation with delayed neutron emission.
PATH | : The path of the previously generated source file (without the .main suffix) |
MODE | : Precursor tracking mode (0 = mesh based, 1 = point-wise) |
Notes:
- Four source files will be required PATH.main, PATH.prec, PATH.live and PATH.precpoints
set dt
set dt NTRSH [ GTRSH ]
Sets probability threshold for delta-tracking. Input values:
NTRSH | : probability threshold for neutrons |
GTRSH | : probability threshold for photons |
Notes:
- Serpent uses delta-tracking by default for both neutrons and photons, but switches to surface-tracking if the probability of sampling virtual collisions (ratio between material total cross section and the majorant) exceeds the given threshold.
- Default probability threshold for both particle types is 0.9, i.e. delta-tracking is used if the ratio between total cross section and majorant is above 0.1.
- set dt 1 means that delta-tracking is always used and set dt 0 that it is never used.
- Use of delta-tracking can be enforced or blocked in individual materials using the set forcedt and set blockdt options
- Integral reaction rates are scored using the collision estimator of neutron flux, which has a few adjustable parameters (see set minxs).
- For more information on tracking modes, see the detailed description on delta- and surface-tracking.
set entr
set entr NX NY NZ [ XMIN XMAX YMIN YMAX ZMIN ZMAX ]
Defines the mesh structure used for calculating fission source entropy. Input values:
NX | : number of mesh cells in x-direction |
NY | : number of mesh cells in y-direction |
NZ | : number of mesh cells in z-direction |
XMIN | : minimum mesh boundary in x-direction |
XMAX | : maximum mesh boundary in x-direction |
YMIN | : minimum mesh boundary in y-direction |
YMAX | : maximum mesh boundary in y-direction |
ZMIN | : minimum mesh boundary in z-direction |
ZMAX | : maximum mesh boundary in z-direction |
Notes:
- Shannon entropy is used to monitor fission source convergence by recording the distribution of source points on mesh.
- The calculation is invoked by setting the generation history record option on (set his).
- The default mesh size is 5x5x5, extending over the entire geometry.
- Monitoring fission source convergence make sense only in criticality source mode.
- For more information, see detailed description on fission source convergence.
set forcedt
set forcedt MAT1 MAT2 ...
Defines the list of materials where delta-tracking is always used. Input values:
MATn | : material names |
Notes:
- This option is used to override selection of tracking mode based on the probability threshold (see set dt) in individual materials.
- Use of delta-tracking can be blocked in individual materials using set blockdt.
- For more information on tracking modes, see the detailed description on delta- and surface-tracking.
- Note to developers: should have different lists for neutrons and photons?
set fsp
set fsp OPT NSKIP
Sets fission source passing between two transport simulations in burnup or coupled calculation. The fission source at the end of one transport calculation is used as the initial source for the next transport calculation.
OPT | : option to switch fission source passing on (1/yes) or off (0/no) |
NSKIP | : number of inactive generations on subsequent steps |
Notes:
- Fission source passing is turned off by default.
- Number of inactive generations is taken from set pop card on the first step and from set fsp on all later steps.
set fum
set gbuf
set gbuf FAC [ BNK ]
Sets the size of photon buffer and event bank. Input values:
FAC | : factor (> 1) defining the buffer size |
BNK | : event bank size |
Notes:
- Photon buffer refers to pre-allocated memory block used to store photon particle data. This memory is needed for putting secondary photons in que, etc..
- The buffer factor defines the buffer size relative to simulated batch size.
- The event bank refers to pre-allocated memory block used to store history data on particle events. This bank is used only with certain special options, such as importance detectors and track plotter.
- The default values depend on simulation mode, and there is no need to adjust the values unless the calculation terminates with an error.
- Note to developers: event bank is now the same for both neutrons and photons.
set gcu
set gcut
set gcut GMAX
Sets generation cut-off for neutrons. Input values:
gmax | : number of simulated generations before cut-off |
Notes:
- The generation cut-off can be used in neutron external source simulations, to limit the length of fission chains.
- Applicable only to neutron external source simulation (invoked using set nps)
- Generation or time cut-off (set tcut) is always needed for neutron external source simulations in super-critical systems.
set his
set his OPT
Sets batch history record on or off. Input values:
OPT | : option to switch batch history record on (1/yes) or off (0/no) |
Notes:
- When invoked, Serpent collects batch-wise data on keff, fission source entropy etc. and produces a separate output file.
- Setting the history option also invokes the calculation of fission source (Shannon) entropy. The entropy mesh parameters can be adjusted using set entr.
- See detailed description on the history output file.
set impl
set impl ICAPT [INXN INUBAR]
Sets implicit reaction modes on or off.
ICAPT | : option to switch implicit capture reactions on (1/yes) or off (0/no) |
INXN | : option to switch implicit nxn reactions on (1/yes) or off (0/no) |
INUBAR | : number of fission neutrons to emit in each fission (nonzero = implicit treatment, 0 = analog treatment) |
Notes:
- Group constant generation requires implicit nxn reactions to be set on.
- If an implicit nubar is given, the weights of the fission neutrons are scaled to conserve the physical number of fission neutrons.
- See separate description of physics options in Serpent for differences to other codes.
set inventory
set inventory MAT1 MAT2 ...
Specifies which nuclides or elements to include in the *_dep.m output file.
MATn | : Nuclide or element to include |
Notes:
- MAT can be: an isotope, e.g. "U-235"; an element, e.g. "Zr"; or a special entry. Special entries include:
- "act" actinides (Z>89)
- "fp" fission products
- "dp" decay products below thorium in the natural actinide decay series
- "ng" noble gases (in the fission product range, He and Rn excluded)
set mcvol
set mcvol NP
Runs the Monte Carlo volume-checker routine to set material volumes before running the transport simulation. Input values:
NP | : number of points sampled in the geometry |
Notes:
- The Monte Carlo based volume calculation routine works by sampling random points in the geometry, and counting the number of hits in every material.
- When invoked, all material volumes are overridden by the results given by the checker routine.
- The volume checker can also be used to produce a separate input file for the volume entries (see detailed description on defining material volumes).
set micro
set memfrac
set memfrac FRAC
Defines the fraction of total system memory Serpent can allocate to its use. If the fraction is exceeded, the simulation will abort. This is mainly to avert the use of swap-memory, which can make the system unresponsive. Input values:
FRAC | : the fraction of system memory that Serpent is allowed to use (between 0 and 1) |
Notes:
- The default fraction is 0.8.
- The fraction can also be set via a SERPENT_MEM_FRAC environmental variable.
- Serpent tries to read the system total memory from the first line of the file /proc/meminfo
set minxs
set minxs LN [ TN LG TG ]
Defines the minimum mean distance for scoring the collision flux estimator (CFE) for photons and neutrons. Input values:
LN | : minimum mean distance for scoring the CFE for neutrons |
TN | : minimum mean time interval for scoring the CFE for neutrons |
LG | : minimum mean distance for scoring the CFE for photons |
TG | : minimum mean time interval for scoring the CFE for photons |
Notes:
- The use of delta-tracking necessitates the use of CFE for scoring the integral reaction rates. The scoring is based on both real and virtual collision to improve the statistics in low density regions (and short time intervals).
- The minimum mean distance is the statistical mean-free-path (mfp) of collisions that contribute to the CFE. Collisions are more frequent if the physical mfp is shorter.
- In time-dependent simulations it may be more convenient to define the minimum mean time between two collisions, to get sufficient statistics for short time bins.
- The default minimum mean scoring distance is 100 cm for both neutrons and photons. Adjusting the distance affects both statistics and running time, but it should be noted that no studies have been performed on what the optimal value should be.
- Only one criterion can be provided for each particle type. If distance is given, time must be set to -1 and vice versa.
- For more information on tracking modes and CFE, see the detailed descriptions on delta- and surface-tracking and result estimators.
set mvol
set mvol MAT1 ZONE1,1 VOL1,1 MAT1 ZONE1,2 VOL1,2 ... MAT2 ZONE2,1 VOL2,1 ...
Sets the volumes of material regions. Input values:
MATm | : name of material m |
ZONEm,n | : index of zone n in material m |
VOLm,n | : volume of zone n in material m |
Notes:
- This option is used to define material volumes manually. The input card is also produced when the Monte Carlo based volume checker routine is invoked.
- The zone index is related to automated depletion zone division, invoked by the div card. If no division is used, the index must be set to zero.
- Another option to define material volumes is to use the vol entry in the material card.
- For more infomation, see detailed description on the definition of material volumes.
set nbuf
set nbuf FAC [ BNK ]
Sets the size of neutron buffer and event bank. Input values:
FAC | : factor (> 1) defining the buffer size |
BNK | : event bank size |
Notes:
- Neutron buffer refers to pre-allocated memory block used to store neutron particle data. This memory is needed for banking fission neutrons for the next generation and putting secondary neutrons in que.
- The buffer factor defines the buffer size relative to simulated batch size.
- The event bank refers to pre-allocated memory block used to store history data on particle events. This bank is used only with certain special options, such as importance detectors and track plotter.
- The default values depend on simulation mode, and there is no need to adjust the values unless the calculation terminates with an error.
- Note to developers: event bank is now the same for both neutrons and photons.
set nfg
set nfylib
set nfylib LIB1 [ LIB2 LIB3 ... ]
Sets the neutron-induced fission yield library file paths. Input values:
LIBn | : library file paths |
Notes:
- Fission yield libraries are standard ENDF format files containing neutron-induced fission yield data.
- If the file path contains special characters it is advised to enclose it within quotes.
- A default directory path can be set by defining environment variable SERPENT_DATA. The code looks for fission yield data files in this path if not found at the absolute.
set nphys
set nphys FISS [ CAPT SCATT ]
Option to set reaction modes for neutrons on and off. Input values:
FISS | : option to handle fission (0 = not handled, 1 = handled) |
CAPT | : option to handle capture (0 = not handled, 1 = handled) |
SCATT | : option to handle scattering (0 = not handled, 1 = handled) |
Notes:
- All reaction modes are handled by default.
- If fission is switched off, it is handled as capture.
set nps
set nps PP [ BTCH TBI ]
Sets parameters for simulated particle population in external source mode. Input values:
PP | : total number of particles |
BTCH | : number of batches |
TBI | : time binning for dynamic mode |
Notes:
- The total number of particles is divided by the given number of batches to give the number of particles per batch.
- Using the nps card sets the mode to external source simulation. Criticality source simulation for neutrons is invoked using set pop.
- If time binning is provided, the simulation is run in the dynamic mode with sequential population control. The bin structure is defined using the tme card.
- Running an external source simulation requires a source, defined by the src card. Source definition also sets the transported particle type.
- Neutron external source simulations are limited to sub-critical systems, unless dynamic mode, time cut-off (set tcut) or generation cut-off (set gcut) is invoked.
- Neutron external source simulations in multiplying systems may require adjusting the neutron buffer (set nbuf).
- Delayed neutron emission is switched off by default in neutron external source simulation (for compatibility with MCNP). Delayed neutrons can be included with set delnu.
set outp
set outp INT
Sets the interval (in cycles) for writing simulation output to files. Input values:
INT | : number of cycles after which the output-files are updated |
Notes:
- Default value is 50.
- Affects files such as _res.m, _det.m as well as mesh plots.
set poi
set poi OPT
Switches the calculation of poison cross sections on or off. Input values:
OPT | : option to switch the calculation of poison cross sections on (1/yes) or off (0/no) |
Notes:
- Poison cross sections include the fission yields and microscopic and macroscopic absorption cross sections of fission product poisons 135Xe and 149Sm, as well as their precursors. The data is part of the homogenized group constant output.
- The calculation requires setting the decay and fission yield library file paths.
set pop
set pop NPG NGEN NSKIP [ K0 BTCH ]
Sets parameters for simulated neutron population in criticality source mode. Input values:
NPG | : number of neutrons per generation |
NGEN | : number of active generations |
NSKIP | : number of inactive generations |
K0 | : initial guess for keff |
BTCH | : batching interval |
Notes:
- The simulation is first run for a number of inactive generations to allow the fission source to converge. This is followed by a number of active generations, during which the results are collected. The statistics are divided in batches, and by default each generation forms its own batch.
- Using the pop card sets the mode to criticality source simulation. External source simulation is invoked using set nps.
- Convergence of fission source can be monitored using Shannon entropy (input parameters set his and set entr).
- Initial guess for keff is 1.0 by default. Setting the value manually may get the simulation going if it terminates on the first generation because of poor initial guess. The value does not affect fission source convergence.
- See detailed descriptions on fission source convergence and statistical effects of batching.
set ppid
set ppid PID
Defines the external code process identifier (PID) number to be used for communication in the POSIX-based coupled calculation communications. Input values:
PID | : Process identifier (PID) of the (parent) process that Serpent should communicate with. |
Notes:
- Setting up a communication mode will enable the coupled calculation mode.
- For more information see: External coupling
set ppw
set ppw UNI LAT
Turns on the calculation of pin-wise peaking factors. The results are printed in variable PPW_POW_FRAC in the [input]_res.m output file. Input values:
UNI | : The universe where the power distribution is calculated. |
LAT | : The lattice where the calculation is performed. |
Notes:
- The peaking factors can be printed to the group constant output with set coefpara.
set relfactor
set relfactor FAC
Sets the underrelaxation factor for the power relaxation used in coupled multi-physics calculations. Input values:
FAC | : underrelaxation factor |
Notes:
- Setting the underrelaxation factor to 0, disables power relaxation altogether. The power distribution written to the output-files will be unrelaxed and only based on the most recent iteration.
set rfr
set rfr STEP FILE
set rfr idx I FILE
Reads material compositions from a binary restart file. Input values:
STEP | : burnup step from which the compositions are obtained |
I | : burnup step index from which the compositions are obtained |
FILE | : name of the binary restart file |
Notes:
- Positive values for step are interpreted as burnup units (MWd/kgU) and negative values as time units (days)
- This option can be used together with the set rfw feature for applying changes in the modeled system during burnup calculation
set rfw
set rfw OPT FILE
Writes material compositions in burnup calculation into a binary restart file. Input values:
OPT | : option to switch writing on (1/yes) or off (0/no) |
FILE | : name of the binary restart file |
Notes:
- Restart file writing is switched off by default.
- This option can be used together with the set rfr feature for applying changes in the modeled system during burnup calculation
set root
set root UNI
Sets the root universe. Input values:
UNI | : universe name |
Notes:
- Root universe is the universe at the lowest level of the geometry hierarchy, and must always be defined. By default the root is set to "0".
- For more information, see detailed description on the universe-based geometry type in Serpent.
set savesrc
set savesrc PATH [ PN PP NX NY NZ ]
Sets up the creation of an initial source to be used in a dynamic simulation with delayed neutron emission.
PATH | : The path of the source file to be created |
PN | : Proportion of tentative neutrons to save (default 1.0) |
PP | : Proportion of tentative precursors to save (default 1.0) |
NX | : Precursor mesh size in x-direction (default 1) |
NY | : Precursor mesh size in y-direction (default 1) |
NZ | : Precursor mesh size in z-direction (default 1) |
Notes:
- Four source files will be generated PATH.main, PATH.prec, PATH.live and PATH.precpoints
- If used in criticality source simulation, the system should be critical and the values will correspond to steady state values
- If used in a dynamic simulation, the values will correspond to end-of-simulation values
- If you are getting a warning from function WriteSourceFile "P larger than 1", you should lower the PN value.
set seed
set seed RNG
Sets the seed value for the random number sequence. Input values:
RNG | : seed value used for the random number sequence |
Notes:
- By default, Serpent gets the RNG seed from system time. This option overrides the value.
set spd
set spd Vn Vp
Overrides the speed of simulated particles. Input values:
Vn | : speed of neutrons (cm/s) |
Vp | : speed of photons (cm/s) |
Notes:
- This option is intended for adjusting particle speeds for better visualization in track plot animations.
- Adjusting the speed (obviously) results in incorrect estimates for all time constants.
- Exceeding the speed of light causes a fatal error in debug mode.
set sfylib
set sfylib LIB1 [ LIB2 LIB3 ... ]
Sets the spontaneous fission yield library file paths. Input values:
LIBn | : library file paths |
Notes:
- Spontaneous fission yield libraries are standard ENDF format files containing spontaneous fission yield data.
- If the file path contains special characters it is advised to enclose it within quotes
set title
set title NAME
Sets a title for the calculation. Input values:
NAME | : title used for the calculation |
Notes:
- The title is printed in the run-time output. If the title is not set, the input file name is printed instead.
set tcut
set tcut Tmax
Sets time cut-off for neutrons and photons. Input values:
Tmax | : time limit for simulated particle histories (in seconds) |
Notes:
- The time cut-off can be used in both neutron and photon external source simulations, to limit the length of particle histories.
- Time or generation cut-off (set gcut) is always needed for neutron external source simulations in super-critical systems.
- Time cut-off is automatically set in the dynamic external source simulation mode.
- Note to developers: this should take independent values for photons and neutrons
set tpa
set tpa Tmin Tmax TAIL NF EVB
Sets parameters for track plot animation. Input values:
Tmin | : starting time of track plot animation (in seconds) |
Tmax | : end time of track plot animation (in seconds) |
TAIL | : tail length of plotted particles (in cm) |
NF | : number of frames |
EVB | : event bank size |
Notes:
- The track plot animation works with the geometry plotter by creating a number of frames that visualize the motion of particles through the geometry.
- The track plotter is invoked using the "-tracks N" command line option, where N is the number of simulated particle histories (if the set tpa option is not defined, the code plots particle tracks in a geometry plot output).
- The routine produces NF frames [input]_trck[n]_frame[m].png, where [input] is the input file name, [n] is an index corresponding to the geometry plot and [m] is the frame index. The frames can be converted into a gif animation using tools like Imagemagick.
- The plotted particles have a tail to better visualize their movement from one collision to the next. The length of this tail is given in centimeters (similar to geometry dimensions). Neutrons are plotted in magenta, photons are plotted in green.
- Storing the simulated collision points requires additional memory, determined by the event bank size. If the given size is insufficient the calculation is terminated with an error message ("Event bank is empty").
- Producing track plot animations may require adjusting the particle buffers (set nbuf and set gbuf).
- The calculation may require a lot of memory for storing the complete simulated histories in neutron-multiplying systems or when particles are split by variance reduction.
- Motion of thermal and fast neutrons cannot be captured simultaneously because of the several orders of magnitude difference in their speed. Thermal systems are best visualized by enforcing all neutrons to travel at the same speed using the set spd option.
set ures
set ures OPT [ NUC1 NUC2 ... ]
Sets unresolved resonance probability table sampling on or off. Input values:
OPT | : option to switch probability table sampling on (1/yes) or off (0/no) |
NUCn | : list of nuclides to which the option is applied to. |
Notes:
- Probability table sampling is switched off by default
- Note to developers: add description of dilution cut-off
- See separate description of physics options in Serpent for differences to other codes.
set usym
set usym UNI AX BC X0 Y0 θ0 θw
Defines a universe symmetry. Input values:
UNI | : universe name |
AX | : symmetry axis (1 = x, 2 = y, 3 = z) |
BC | : boundary condition (2 = reflective, 3 = periodic) |
X0 | : x-coordinate of the origin |
Y0 | : y-coordinate of the origin |
θ0 | : azimuthal position where the symmetry segment starts (degrees) |
θw | : width of the segment (degrees) |
Notes:
- Universe symmetries can be used to simplify construction of complex geometries.
- Symmetries can also be used to reduce the number of burnable material zones when automated depletion zone division is applied.
- When symmetries are used, it is important to pay attention to the definition of material volumes.
- For more information, see examples on universe symmetries.
References
- ^ Leppänen, J. "Serpent – a Continuous-energy Monte Carlo Reactor Physics Burnup Calculation Code." User manual, June 18, 2015.