Input syntax manual
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 ifc (interface file)
- 1.7 include (read another input file)
- 1.8 lat (regular lattice definition)
- 1.9 mat (material definition)
- 1.10 mesh (mesh plot definition)
- 1.11 pin (pin geometry definition)
- 1.12 plot (geometry plot definition)
- 1.13 rmtx (response matrix based importance map solver)
- 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)
- 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 declib
- 2.11 set delnu
- 2.12 set depout
- 2.13 set dfsol
- 2.14 set dynsrc
- 2.15 set dt
- 2.16 set entr
- 2.17 set forcedt
- 2.18 set fsp
- 2.19 set fum
- 2.20 set gbuf
- 2.21 set gcu
- 2.22 set gcut
- 2.23 set his
- 2.24 set impl
- 2.25 set inventory
- 2.26 set mcvol
- 2.27 set micro
- 2.28 set memfrac
- 2.29 set minxs
- 2.30 set mvol
- 2.31 set nbuf
- 2.32 set nfg
- 2.33 set nfylib
- 2.34 set nphys
- 2.35 set nps
- 2.36 set outp
- 2.37 set poi
- 2.38 set pop
- 2.39 set ppid
- 2.40 set ppw
- 2.41 set relfactor
- 2.42 set rfr
- 2.43 set rfw
- 2.44 set root
- 2.45 set savesrc
- 2.46 set seed
- 2.47 set sfylib
- 2.48 set title
- 2.49 set tcut
- 2.50 set ures
- 2.51 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:
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.
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 ]
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'):
- 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.
- 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.
rmtx (response matrix based importance map solver)
rmtx 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:
NI | : maximum number of iterations | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
f | : normalization factor | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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)
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:
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:
solid 3 INTERFACE_FILE Creates an unstructured mesh-based geometry universe with unstructured mesh-based temperature and/or density distributions. Input values are:
src (source definition)strans (surface transformation)surf (surface definition)surf NAME TYPE [ PARAM1 PARAM2 ... ] Defines a surface. Input values:
Notes:
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:
Notes:
Input optionsInput 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 acelibset acelib FILE Sets the cross section library directory file to use with the simulation. Input values:
Notes:
set adfset adf UNI SURF SYM Sets parameters for the calculation of assembly discontinuity factors. Input values:
Notes:
set arrset arr MODEN [ MODEG ] Sets analog reaction rate calculation on or off. Input values:
Notes:
set bcset bc MODE Sets the boundary conditions for all outer boundaries of the geometry. Input values:
set bc MODE ALB Sets the boundary conditions with albedo for all outer boundaries of the geometry. Input values:
set bc MODEX MODEY MODEZ Sets the boundary conditions separately for x-, y- and z-directions. Input values:
set bc MODEX MODEY MODEZ ALB Sets the boundary conditions with albedo separately for x-, y- and z-directions. Input values:
Notes:
set blockdtset blockdt MAT1 MAT2 ... Defines the list of materials where delta-tracking is never used. Input values:
Notes:
set ccmaxiterset ccmaxiter NITER Sets the maximum number of coupled calculation iterations. Input values:
Notes:
set ccmaxpopset ccmaxpop CPOP Sets the maximum total live population to simulate in a coupled calculation. Input values:
Notes:
set coefparaset coefpara FMT [ PARAM1 PARAM2 ... ] Defines the parameters included in the separate group constant output file. Input values:
Notes:
set comfileset comfile INFILE OUTFILE Defines the communication files used in the file-based coupled calculation communications. Input values:
Notes:
set declibset declib LIB1 [ LIB2 LIB3 ... ] Sets the decay data library file paths. Input values:
Notes:
set delnuset delnu OPT Sets delayed neutron emission on or off. Input values:
Notes:
set depoutset depout MODE Controls which burnable material compositions are printed into the _dep.m output file in case of divided materials. Input values:
Notes:
set dfsolset dfsol MODE [ NP ] Options for homogeneous diffusion flux solver. Input values:
Notes:
set dynsrcset dynsrc PATH [ MODE ] Links previously generated steady state source distributions to be used in a transient simulation with delayed neutron emission.
Notes:
set dtset dt NTRSH [ GTRSH ] Sets probability threshold for delta-tracking. Input values:
Notes:
set entrset entr NX NY NZ [ XMIN XMAX YMIN YMAX ZMIN ZMAX ] Defines the mesh structure used for calculating fission source entropy. Input values:
Notes:
set forcedtset forcedt MAT1 MAT2 ... Defines the list of materials where delta-tracking is always used. Input values:
Notes:
set fspset 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.
Notes:
set fumset gbufset gbuf FAC [ BNK ] Sets the size of photon buffer and event bank. Input values:
Notes:
set gcuset gcutset gcut GMAX Sets generation cut-off for neutrons. Input values:
Notes:
set hisset his OPT Sets batch history record on or off. Input values:
Notes:
set implset impl ICAPT [INXN INUBAR] Sets implicit reaction modes on or off.
Notes:
set inventoryset inventory MAT1 MAT2 ... Specifies which nuclides or elements to include in the *_dep.m output file.
Notes:
set mcvolset mcvol NP Runs the Monte Carlo volume-checker routine to set material volumes before running the transport simulation. Input values:
Notes:
set microset memfracset 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:
Notes:
set minxsset minxs LN [ TN LG TG ] Defines the minimum mean distance for scoring the collision flux estimator (CFE) for photons and neutrons. Input values:
Notes:
set mvolset mvol MAT1 ZONE1,1 VOL1,1 MAT1 ZONE1,2 VOL1,2 ... MAT2 ZONE2,1 VOL2,1 ... Sets the volumes of material regions. Input values:
Notes:
set nbufset nbuf FAC [ BNK ] Sets the size of neutron buffer and event bank. Input values:
Notes:
set nfgset nfylibset nfylib LIB1 [ LIB2 LIB3 ... ] Sets the neutron-induced fission yield library file paths. Input values:
Notes:
set nphysset nphys FISS [ CAPT SCATT ] Option to set reaction modes for neutrons on and off. Input values:
Notes:
set npsset nps PP [ BTCH TBI ] Sets parameters for simulated particle population in external source mode. Input values:
Notes:
set outpset outp INT Sets the interval (in cycles) for writing simulation output to files. Input values:
Notes:
set poiset poi OPT Switches the calculation of poison cross sections on or off. Input values:
Notes:
set popset pop NPG NGEN NSKIP [ K0 BTCH ] Sets parameters for simulated neutron population in criticality source mode. Input values:
Notes:
set ppidset ppid PID Defines the external code process identifier (PID) number to be used for communication in the POSIX-based coupled calculation communications. Input values:
Notes:
set ppwset relfactorset relfactor FAC Sets the underrelaxation factor for the power relaxation used in coupled multi-physics calculations. Input values:
Notes:
set rfrset rfr STEP FILE set rfr idx I FILE Reads material compositions from a binary restart file. Input values:
Notes:
set rfwset rfw OPT FILE Writes material compositions in burnup calculation into a binary restart file. Input values:
Notes:
set rootset root UNI Sets the root universe. Input values:
Notes:
set savesrcset 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.
Notes:
set seedset seed RNG Sets the seed value for the random number sequence. Input values:
Notes:
set sfylibset sfylib LIB1 [ LIB2 LIB3 ... ] Sets the spontaneous fission yield library file paths. Input values:
Notes:
set titleset title NAME Sets a title for the calculation. Input values:
Notes:
set tcutset tcut TMAX Sets time cut-off for neutrons and photons. Input values:
Notes:
set uresset ures OPT [ NUC1 NUC2 ... ] Sets unresolved resonance probability table sampling on or off. Input values:
Notes:
set usymset usym UNI AX BC X0 Y0 θ0 θw Defines a universe symmetry. Input values:
Notes:
References
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