Output parameters

This page lists the output parameters in the main [input]_res.m output file.

General output parameters

Version, title and date

Parameter	Size	Description
VERSION	(string)	Code version
COMPILE_DATE	(string)	Date when the source code was compiled
DEBUG	1	Debug flag indicating if the DEBUG option was set when the source code was compiled
TITLE	(string)	Title defined using the set title input option
CONFIDENTIAL_DATA	1	Confidentiality flag set using the set confi input option
INPUT_FILE_NAME	(string)	File name of the main input file
WORKING_DIRECTORY	(string)	Directory path where the simulation was run
HOSTNAME	(string)	Host name where the simulation was run
CPU_TYPE	(string)	CPU type of the machine where the simulation was run (parsed from /proc/cpuinfo)
CPU_MHZ	(string)	CPU clock frequency of the machine where the simulation was run (parsed from /proc/cpuinfo)
START_DATE	(string)	Date and time when the simulation was started
COMPLETE_DATE	(string)	Date and time when this output was printed

Run parameters

Parameter	Size	Description
POP	1	Population size defined using the set pop input option (criticality) or the set nps input option (external source)
CYCLES	1	Number of active cycles defined using the set pop input option
SKIP	1	Number of inactive cycles defined using the set pop input option
BATCH_INTERVAL	1	Batching interval defined using the set pop input option
BATCHES	1	Number of batches defined using the set nps input option
SRC_NORM_MODE	1	Source normalization mode
SEED	1	Random number seed taken from system time or defined using the set seed input option
UFS_MODE	1	Uniform fission source mode defined using the set ufs input option
UFS_ORDER	1	Uniform fission exponential factor using the set ufs input option
NEUTRON_TRANSPORT_MODE	1	Flag indicating whether or not neutron transport simulation is on
PHOTON_TRANSPORT_MODE	1	Flag indicating whether or not neutron transport simulation is on
GROUP_CONSTANT_GENERATION	1	Flag indicating whether or not group constant generation is on
B1_CALCULATION	3	Flag indicating whether or not B1 calculation is on
B1_BURNUP_CORRECTION	1	Flag indicating whether or not B1 burnup correction is on
CRIT_SPEC_MODE	2	Critical spectrum modes
IMPLICIT_REACTION_RATES	1	Flag indicating whether or implicit reaction rates are used for group constant generation
VR_ITER_IDX	1	Variance reduction iteration index when output was printed (see wwin card)

Domain decomposition

Parameter	Size	Description
DD_MODE	1	Domain decomposition mode defined using the set dd input option
DD_NEUTRONS_TO_LIMBO	M	Neutrons sent to limbo (transferral buffer) at each domain
DD_NEUTRONS_FROM_LIMBO	M	Neutrons received from limbo (transferral buffer) at each domain

Optimization

Parameter	Size	Description
OPTIMIZATION_MODE	1	Optimization mode defined using the set opti input option
RECONSTRUCT_MICROXS	1	Flag indicating whether or not microscopic cross sections are reconstructed on the unionized energy grid
RECONSTRUCT_MACROXS	1	Flag indicating whether or not macroscopic cross sections are reconstructed on the unionized energy grid
DOUBLE_INDEXING	1	Double indexing option defined using the set dix input option
MG_MAJORANT_MODE	1	Multi-group majorant mode
SPECTRUM_COLLAPSE	1	Spectrum collapse method flag (set xscalc input option)

Parallelization

Parameter	Size	Description
MPI_TASKS	1	Number of parallel MPI tasks
OMP_THREADS	1	Number of parallel OpenMP threads
MPI_REPRODUCIBILITY	1	MPI reproducibility option defined by the set repro input option
OMP_REPRODUCIBILITY	1	OpenMP reproducibility option defined by the set repro input option
OMP_HISTORY_PROFILE	N	Fraction of particle histories run for each parallel OpenMP thread
SHARE_BUF_ARRAY	1	Shared buffer flag
SHARE_RES2_ARRAY	1	Shared RES2 array flag
OMP_SHARED_QUEUE_LIM	1	Limiting value for using shared particle queue

File paths

Notes:

• Only the first file path listed is displayed

Parameter	Size	Description
XS_DATA_FILE_PATH	(string)	Cross section directory file path defined using the set acelib input option
DECAY_DATA_FILE_PATH	(string)	Radioactive decay data file path defined using the set declib input option
SFY_DATA_FILE_PATH	(string)	Spontaneous fission yield data file path defined using the set sfylib input option
NFY_DATA_FILE_PATH	(string)	Neutron-induced fission yield data file path defined using the set nfylib input option
BRA_DATA_FILE_PATH	(string)	Isomeric branching ratio data file path defined using the set bralib input option
PHOTON_PHYS_DIRECTORY	(string)	Photon physics directory path defined using the set pdatadir input option

Misc. statistics

Collision and reaction sampling (neutrons/photons)

Notes:

• The first single/pair value corresponds to neutrons and, the second single/pair value corresponds to photons.

Parameter	Size	Description
MEAN_SRC_WGT	2/2	Mean source weight for non-criticality calculations (neutrons/photons)
SOURCE_SAMPLING_EFF	2/2	Source sampling efficiency for non-criticality calculations (neutrons/photons)
MEAN_SRC_WW_SPLIT	2/2	Mean source weight-window splitting in variance reduction (neutrons/photons)
MEAN_SRC_WW_EFF	2/2	Mean source weight-window sampling efficiency in variance reduction (neutrons/photons)
WW_BALA_ROULETE	2/2	Mean weight-window balance due to Russian roulette in variance reduction (neutrons/photons)
WW_BALA_SPLIT	2/2	Mean weight-window balance due to splitting in variance reduction (neutrons/photons)
MIN_MACROXS	2/2	Macroscopic cross section corresponding to the minimum mfp used for scoring the collision flux estimator (see the set cfe input option)
DT_THRESH	1/1	Probability threshold used for switching to delta-tracking (see the set dt input option)
ST_FRAC	2/2	Fraction of paths sampled using surface-tracking
DT_FRAC	2/2	Fraction of paths sampled using delta-tracking
DT_EFF	2/2	Delta-tracking efficiency
IFC_COL_EFF	2/2	Efficiency of interface collision rejection (see ifc card)
REA_SAMPLING_EFF	2/2	Reaction sampling efficiency
REA_SAMPLING_FAIL	2/2	Fraction of failed reaction samples
TMS_SAMPLING_EFF	2	Target motion sampling method, TMS, sampling efficiency (see tms option, in mat card)
TOT_COL_EFF	2/2	Total collision efficiency
AVG_TRACKING_LOOPS	2/2, 2/2	Average number of tracking loops per history and, fraction of failed tracking loops
TMS_FAIL_STAT	8	TMS fail statistics: total samples, majorant fail, lower limit fail, upper limit fail (see tms option, in mat card)
DBRC_EXCEED_FRAC	1	Doppler-broadening rejection correction, DBRC, majorant exceed fraction (see set dbrc input option)
AVG_TRACKS	2/2	Average number of tracks per history
AVG_REAL_COL	2/2	Average number of real collisions per history
AVG_VIRT_COL	2/2	Average number of virtual collisions per history
AVG_SURF_CROSS	2/2	Average number of surface crossings per history (NOTE: accurate only in ST mode)
LOST_PARTICLES	1	Number of lost particles

STL geometries

Parameter	Size	Description
STL_RAY_TEST	5	STL-ray-tracing test: total, ray is too parallel to facet, intersection point is too close to edge, facet is too close to search mesh cell boundary, two facets overlap
STL_ENFORCE_ST	1	Flag indicating whether or not delta tracking is enforced in STL geometries

Importance solver

Parameter	Size	Description
NEIGHBOUR_SEARCH_FAIL	2	Response matrix calculation fail rate

Run statistics

Parameter	Size	Description
CYCLE_IDX	1	Cycle index when output was printed
SIMULATED_HISTORIES	1	Number of simulated histories when output was printed
MEAN_POP_SIZE	1	Mean population size
MEAN_POP_WGT	1	Mean population weight
SIMULATION_COMPLETED	1	Flag indicating whether or not the simulation was completed

Running times

Notes:

• All times in minutes
• In burnup calculations the first value provides the cumulative and the second value the cycle-wise value

Parameter	Size	Description
TOT_CPU_TIME	1	Total CPU time
RUNNING_TIME	1	Total wall-clock running time
INIT_TIME	1(2)	Wall-clock time spent for initialization
PROCESS_TIME	1(2)	Wall-clock time spent for processing
TRANSPORT_CYCLE_TIME	1(3)	Wall-clock time spent for transport simulation
FINIX_SOLUTION_TIME	1	Wall-clock time spent for FINIX solution
BURNUP_CYCLE_TIME	1(2)	Wall-clock time spent for burnup solution
BATEMAN_SOLUTION_TIME	1(2)	Wall-clock time spent for solving the Bateman equations
MPI_OVERHEAD_TIME	1(2)	Wall-clock time spent MPI communication
DD_OVERHEAD_TIME	1	Wall-clock time spent for DD algorithm (see set dd input option)
RMX_SOLUTION_TIME	1	Wall-clock time spent for response matrix solution (see wwgen / wwin cards or set sca input option)
LEAKAGE_CORR_SOL_TIME	1	Wall-clock time spent for leakage correction solution (see set fum input option)
ESTIMATED_RUNNING_TIME	1(2)	Estimated total wall-clock running time
CPU_USAGE	1	Total CPU usage fraction
TRANSPORT_CPU_USAGE	1(2)	CPU usage fraction in transport simulation
OMP_PARALLEL_FRAC	1	Fraction of time spent in OpenMP parallel loops

Memory usage

Notes:

• All values are in megabytes
• Serpent allocates memory in fixed segments, so the allocated memory size may be larger than what is needed for the simulation

Parameter	Size	Description
AVAIL_MEM	1	Available memory size
ALLOC_MEMSIZE	1	Allocated memory size
MEMSIZE	1	Used memory size
XS_MEMSIZE	1	Memory size used for storing cross sections
MAT_MEMSIZE	1	Memory size used for storing material-wise data
RES_MEMSIZE	1	Memory size used for storing results
IFC_MEMSIZE	1	Memory size used for data for multi-physics interface data
RMX_MEMSIZE	1	Memory sized used for storing response matrix-wise data
MISC_MEMSIZE	1	Memory size used for data for miscellaneous data
UNKNOWN_MEMSIZE	1	Memory size used for data for uncategorized data
UNUSED_MEMSIZE	1	Allocated memory not used for anything

Geometry parameters

Parameter	Size	Description
TOT_CELLS	1	Total number of cells
UNION_CELLS	1	Total number of cells defined using unions

Neutron energy grid

Parameter	Size	Description
NEUTRON_ERG_TOL	1	Reconstruction tolerace for unionized energy grid
NEUTRON_ERG_NE	1	Number of points in neutron unionized energy grid
NEUTRON_EMIN	1	Minimum energy for neutron cross section data
NEUTRON_EMAX	1	Maximum energy for neutron cross section data

Photon energy grid

Parameter	Size	Description
PHOTON_ERG_NE	1	Number of points in photon unionized energy grid
PHOTON_EMIN	1	Minimum energy for photon cross section data
PHOTON_EMAX	1	Maximum energy for photon cross section data

Unresolved resonance probability table sampling

Parameter	Size	Description
URES_DILU_CUT	1	Density cut-off used for unresolved resonance probability table sampling
URES_EMIN	1	Minimum energy for unresolved resonance range
URES_EMAX	1	Maximum energy for unresolved resonance range
URES_AVAIL	1	Number of nuclides with probability table data
URES_USED	1	Number of nuclides for which probability table sampling was used

Nuclides and reaction channels

Parameter	Size	Description
TOT_NUCLIDES	1	Total number of nuclides
TOT_TRANSPORT_NUCLIDES	1	Total number of nuclides with transport cross sections
TOT_DOSIMETRY_NUCLIDES	1	Total number of nuclides with dosimetry cross sections
TOT_DECAY_NUCLIDES	1	Total number of decay nuclides (without transport cross sections)
TOT_PHOTON_NUCLIDES	1	Total number of nuclides with photon cross section data
TOT_REA_CHANNELS	1	Total number of reaction channels
TOT_TRANSMU_REA	1	Total number of transmutation reactions

Physics

Neutron physics options

Parameter	Size	Description
USE_DELNU	1	Flag indicating whether or not delayed neutron emission is on (see set delnu input option)
USE_URES	1	Flag indicating whether or not unresolved resonance probability table sampling is on (see set ures input option)
USE_DBRC	1	Flag indicating whether or not Doppler-broadening rejection correction is on (see set dbrc input option)
IMPL_CAPT	1	Flag indicating whether or not implicit capture reaction mode is on (see set impl input option)
IMPL_NXN	1	Flag indicating whether or not implicit nxn reaction mode is on (see set impl input option)
IMPL_FISS	1	Flag indicating whether or not implicit fission reaction mode is on (see set impl input option)
IMPL_FISS_NUBAR	1	Flag indicating wether or not implicit fission nubar reaction mode is on (see set impl input option)
DOPPLER_PREPROCESSOR	1	Flag indicating whether or not Doppler-broadening preprocessor is on (see tmp option, in mat card)
TMS_MODE	1	Flag indicating whether or not target motion sampling is on (see tms option, in mat card)
SAMPLE_FISS	1	Flag indicating whether or not fission reactions are handled (see set nphys input option)
SAMPLE_CAPT	1	Flag indicating whether or not capture reactions are handled (see set nphys input option)
SAMPLE_SCATT	1	Flag indicating whether or not scattering reactions are handled (see set nphys input option)

Photon physics options

Parameter	Size	Description
COMPTON_EKN	1	Photon energy above which Klein-Nishina is used for calculating energy and direction of the scattered photons (see set ekn input option)
COMPTON_DOPPLER	1	Flag indicating whether or not Doppler broadening method for the energy spectrum of the scattered photons is on (see set cdop input option)
COMPTON_EANG	1	Flag indicating whether or not Compton electron angular distribution model is on (see set cea input option)
PHOTON_TTB	1	Flag indicating whether or not thick-target bremsstrahlung approximation for modelling electrons and positrons is on (see set ttb input option)

Photon production

Parameter	Size	Description
PHOTON_SAMPLING_MODE	1	Flag indicating whether or not photon production from neutron reactions mode is on (see set ngamma input option)
PHOTON_SAMPLING_FAIL	2	Fraction of failed photon samples

Energy deposition

Notes:

• The list of fission energy release components includes: (1) EFR, kinetic energy of the fission products (following prompt neutron emission from the fission fragments); (2) ENP, kinetic energy of the prompt fission neutrons; (3) END, kinetic energy of the delayed fission neutrons; (4) EGP, total energy release by the emission of prompt gamma rays; (5) EGD, total energy release by the emission of delayed gamma rays; (6) EB, total energy release by delayed beta’s; (7) ENU, energy carried away by neutrinos; (8) ER, total energy less the energy of the neutrinos (ET - ENU), equal to the pseudo-Q-value in File 3 for MT=18; (9) ET, sum of all the partial energies previously listed, corresponding to the total energy release per fission and equal the Q-value.

Parameter	Size	Description
EDEP_MODE	1	Energy deposition mode (see set edepmode input option)
EDEP_DELAYED	1	Energy of delayed components in energy deposition calculations (see set edepdel input option)
EDEP_KEFF_CORR	1	Flag indicating whether or not correction for energy deposition estimates in non-critical systems (see set edepkcorr input option)
EDEP_LOCAL_EGD	1	Energy distribution of delayed components in energy deposition calculations, mode 3 (see set edepdel input option)
EDEP_COMP	9	Fission energy release components: EFR, ENP, END, EGP, EGD, EB, ENU, ER, ET.
EDEP_CAPT_E	1	Additional energy release in capture reactions, mode 1 (see set edepmode input option)

Radioactivity data

Notes:

• The values are given at the current burnup point (depletion step).

Parameter	Size	Description
TOT_ACTIVITY	1	Total activity
TOT_DECAY_HEAT	1	Total decay heat
TOT_SF_RATE	1	Total spontaneous fission rate
ACTINIDE_ACTIVITY	1	Actinide activity
ACTINIDE_DECAY_HEAT	1	Actinide decay heat
FISSION_PRODUCT_ACTIVITY	1	Fission product activity
FISSION_PRODUCT_DECAY_HEAT	1	Fission product decay heat
INHALATION_TOXICITY	1	Total inhalation toxicity
INGESTION_TOXICITY	1	Total ingestion toxicity
ACTINIDE_INH_TOX	1	Actinide inhalation toxicity
ACTINIDE_ING_TOX	1	Actinide ingestion toxicity
FISSION_PRODUCT_INH_TOX	1	Fission product inhalation toxicity
FISSION_PRODUCT_ING_TOX	1	Fission product ingestion toxicity
SR90_ACTIVITY	1	Sr-90 activity
TE132_ACTIVITY	1	Te-132 activity
I131_ACTIVITY	1	I-131 activity
I132_ACTIVITY	1	I-132 activity
CS134_ACTIVITY	1	Cs-134 activity
CS137_ACTIVITY	1	Cs-137 activity
PHOTON_DECAY_SOURCE	2	Total photon decay source rate and total released gamma decay
NEUTRON_DECAY_SOURCE	1	Total neutron decay source rate
ALPHA_DECAY_SOURCE	1	Total alpha decay source rate
ELECTRON_DECAY_SOURCE	1	Total beta decay source rate

Normalization coefficient

Parameter	Size	Description
NORM_COEF	2/2	Proportionality constant between the simulated events and the "physical" events that the simulated events represent, for neutrons and photons.

Parameters for burnup calculation

Parameter	Size	Description
BURN_MATERIALS	1	Number of depleted materials.
BURN_MODE	1	Burnup mode: 1 = TTA, 2 = CRAM (see set bumode input option).
BURN_STEP	1	Burnup step index.
BURN_RANDOMIZE_DATA	3	Flag indicating whether or not randomize data is set on: decay constants, fission yields and decay heat (see set rnddec input option).
BURNUP	2	Burnup at the current step (in MWd/kgU): cumulative and real-cumulative.
BURN_DAYS	2	Number of burn days at the current step: cumulative and step-wise.
FIMA	3	Number of fissions per initial fissile atom at the current step: relative step-wise, increment step-wise, final step-wise.

Coefficient calculation

Parameter	Size	Description
COEF_IDX	2	Coefficient index when output is printed and total number of coefficient calculations
COEF_BRANCH	1	Branch index within coefficient calculation when output is printed
COEF_BU_STEP	1	Burnup step at the given coefficient calculation when output is printed

Analog reaction rate estimators

Parameter	Size	Description
CONVERSION_RATIO	2	Analog estimate of conversion rate, ratio between fissile production and loss rate
TH232_FISS	4	Analog estimate of Th-232 fission rate (total/fraction)
U233_FISS	4	Analog estimate of U-233 fission rate (total/fraction)
U235_FISS	4	Analog estimate of U-235 fission rate (total/fraction)
U238_FISS	4	Analog estimate of U-238 fission rate (total/fraction)
PU239_FISS	4	Analog estimate of Pu-239 fission rate (total/fraction)
PU240_FISS	4	Analog estimate of Pu-240 fission rate (total/fraction)
PU241_FISS	4	Analog estimate of Pu-241 fission rate (total/fraction)
TH232_CAPT	4	Analog estimate of Th-232 capture rate (total/fraction)
U233_CAPT	4	Analog estimate of U-233 capture rate (total/fraction)
U235_CAPT	4	Analog estimate of U-235 capture rate (total/fraction)
U238_CAPT	4	Analog estimate of U-238 capture rate (total/fraction)
PU239_CAPT	4	Analog estimate of Pu-239 capture rate (total/fraction)
PU240_CAPT	4	Analog estimate of Pu-240 capture rate (total/fraction)
PU241_CAPT	4	Analog estimate of Pu-241 capture rate (total/fraction)
XE135_CAPT	4	Analog estimate of Xe-135 capture rate (total/fraction)
XE135M_CAPT	4	Analog estimate of Xe-135m capture rate (total/fraction)
SM149_CAPT	4	Analog estimate of Sm-149 capture rate (total/fraction)

Particle balance

Neutron balance (particles/weight)

Parameter	Size	Description
BALA_SRC_NEUTRON_SRC	1/1	Neutron produced by external source
BALA_SRC_NEUTRON_FISS	1/1	Neutron produced by fission
BALA_SRC_NEUTRON_NXN	1/1	Neutron produced by scattering
BALA_SRC_NEUTRON_VR	1/1	Neutron produced by variance reduction (Russian roulette, splitting)
BALA_SRC_NEUTRON_TOT	1/1	Total neutron produced
BALA_LOSS_NEUTRON_CAPT	1/1	Neutron lost by capture
BALA_LOSS_NEUTRON_FISS	1/1	Neutron lost by fission
BALA_LOSS_NEUTRON_LEAK	1/1	Neutron lost by leakage
BALA_LOSS_NEUTRON_CUT	1/1	Neutron lost by cut-off
BALA_LOSS_NEUTRON_ERR	1/1	Neutron lost by failed tracking
BALA_LOSS_NEUTRON_TOT	1/1	Total neutron lost
BALA_NEUTRON_DIFF	1/1	Difference between total neutron produced and lost

Photon balance (particles/weight/energy-weighted)

Parameter	Size	Description
BALA_SRC_PHOTON_SRC	1/1/1	Photon produced by external source
BALA_SRC_PHOTON_TTB	1/1/1	Photon produced by bremsstrahlung
BALA_SRC_PHOTON_ANNIH	1/1/1	Photon produced by annihilation
BALA_SRC_PHOTON_FLUOR	1/1/1	Photon produced by fluorescence
BALA_SRC_PHOTON_NREA	1/1/1	Photon produced by neutron reaction
BALA_SRC_PHOTON_VR	1/1/1	Photon produced by variance reduction (Russian roulette, splitting)
BALA_SRC_PHOTON_TOT	1/1/1	Total photon produced
BALA_LOSS_PHOTON_CAPT	1/1	Photon lost by capture
BALA_LOSS_PHOTON_LEAK	1/1	Photon lost by leakage
BALA_LOSS_PHOTON_CUT	1/1	Photon lost by cut-off
BALA_LOSS_PHOTON_ERR	1/1	Photon lost by failed tracking
BALA_LOSS_PHOTON_TOT	1/1	Total photon lost
BALA_PHOTON_DIFF	1/1	Difference between total photon produced and lost

Integral results

Normalized total reaction rates (neutrons)

Notes:

• In burnup calculations the values correspond to total, burnable and non-burnable rates

Parameter	Size	Description
TOT_POWER	2(6)	Total neutron fission power
TOT_POWDENS	2(6)	Total neutron fission power density
TOT_GENRATE	2(6)	Total neutron generation rate
TOT_FISSRATE	2(6)	Total neutron fission rate
TOT_CAPTRATE	2(6)	Total neutron capture rate
TOT_ABSRATE	2(6)	Total neutron absorption rate
TOT_SRCRATE	2(6)	Total neutron source rate
TOT_FLUX	2(6)	Total neutron flux
TOT_PHOTON_PRODRATE	4	Total neutron-photon production rate (implicit/analog)
TOT_LEAKRATE	2	Total neutron leakage rate
ALBEDO_LEAKRATE	2	Albedo neutron leakage rate
TOT_LOSSRATE	2	Total neutron loss rate
TOT_CUTRATE	2	Total neutron energy cut-off rate
TOT_RR	2	Total neutron reaction rate
TOT_XE135_ABSRATE	2	Total neutron absorption rate in Xe-135
TOT_XE135M_ABSRATE	2	Total neutron absorption rate in Xe-135m
TOT_SM149_ABSRATE	2	Total neutron absorption rate in Sm-149
INI_FMASS	1	Initial fissile mass
TOT_FMASS	1	Total fissile mass
INI_BURN_FMASS	1	Initial fissile mass in burnable materials
TOT_BURN_FMASS	1	Total fissile mass in burnable materials

Normalized total reaction rates (photons)

Parameter	Size	Description
TOT_PHOTON_LEAKRATE	2	Total photon leakage rate
TOT_PHOTON_CUTRATE	2	Total photon energy cut-off rate
PHOTOELE_CAPT_RATE	2	Photo-electric photon capture rate
PAIRPROD_CAPT_RATE	2	Pair production photon capture rate
TOT_PHOTON_LOSSRATE	2	Total photon loss rate
TOT_PHOTON_SRCRATE	2	Total photon source rate
TOT_PHOTON_RR	2	Total photon reaction rate
TOT_PHOTON_FLUX	2	Total photon flux
TOT_PHOTON_HEATRATE	2	Total photon heating rate

Equilibrium Xe-135 iteration

Parameter	Size	Description
I135_EQUIL_CONC	2	Averaged equilibrium I-135 concentration (see set xenon input option)
XE135_EQUIL_CONC	2	Averaged equilibrium Xe-135 concentration (see set xenon input option)
XE135M_EQUIL_CONC	2	Averaged equilibrium Xe-135m concentration (see set xenon input option)

Equilibrium Sm-149 iteration

Parameter	Size	Description
SM149_EQUIL_CONC	2	Averaged equilibrium Sm-149 concentration (see set samarium input option)
PM149_EQUIL_CONC	2	Averaged equilibrium Pm-149 concentration (see set samarium input option)

Iteration factor

Parameter	Size	Description
ITER_FACTOR	2	Iteration factor of critical density iteration (see set iter nuc input option) or albedo iteration (see set iter alb input option)

Six-factor formula

Parameter	Size	Description
SIX_FF_ETA	2	Analog estimate of average number of neutrons emitted per thermal neutron absorbed in fuel
SIX_FF_F	2	Analog estimate of thermal utilization factor
SIX_FF_P	2	Analog estimate of resonance escape probability
SIX_FF_EPSILON	2	Analog estimate of fast fission factor
SIX_FF_LF	2	Analog estimate of fast non-leakage probability
SIX_FF_LT	2	Analog estimate of thermal non-leakage probability
SIX_FF_KINF	2	Analog estimate of six-factor kinf (four-factor keff)
SIX_FF_KEFF	2	Analog estimate of six-factor keff

Fission neutron and energy production

Parameter	Size	Description
NUBAR	2	Average fission neutron yield
FISSE	2	Average fission energy production

Criticality eigenvalues / Multiplication factor external source

Parameter	Size	Description
ANA_KEFF	6(2)	Analog estimate of keff: total, prompt and delayed neutron contribution.
IMP_KEFF	2	Implicit estimate of keff.
COL_KEFF	2	Collision estimate of keff.
ABS_KEFF	2	Absorption estimate of keff.
ABS_KINF	2	Absorption estimate of kinf.
ANA_EXT_K	20	Generation-wise source multiplication factors in external source mode
SRC_MULT	2	Source multiplication factor in external source mode
MEAN_NGEN	2	Mean number of generations in external source mode
PROMPT_GEN_POP	NG	Prompt fission population generation fraction
PROMPT_GEN_CUMU	NG	Prompt fission cumulative generation fraction
PROMPT_GEN_TIMES	NG	Prompt fission time generation fraction
PROMPT_CHAIN_LENGTH	2	Mean prompt chain length in external source mode
GEOM_ALBEDO	6	Fixed or iterated value for albedo boundary condition for x-,y- and z-directions (see set bc or set iter alb input options).

Wielandt method

Parameter	Size	Description
WIELANDT_K	2	Wielandt’s method shifted eigenvalue (see set wie input option)
WIELANDT_P	2	Wielandt’s method neutron banking probability (see set wie input option)

ALF (Average lethargy of neutrons causing fission)

Parameter	Size	Description
ANA_ALF	2	Analog estimate of average lethargy of neutrons causing fission
IMP_ALF	2	Implicit estimate of average lethargy of neutrons causing fission

EALF (Energy corresponding to average lethargy of neutrons causing fission)

Parameter	Size	Description
ANA_EALF	2	Analog estimate of energy corresponding to the average lethargy of neutrons causing fission
IMP_EALF	2	Implicit estimate of energy corresponding to the average lethargy of neutrons causing fission

AFGE (Average energy of neutrons causing fission)

Parameter	Size	Description
ANA_AFGE	2	Analog estimate of average energy of neutrons causing fission
IMP_AFGE	2	Implicit estimate of average energy of neutrons causing fission

Time constants

Forward-weighted delayed neutron parameters

Parameter	Size	Description
PRECURSOR_GROUPS	1	Number of delayed neutron precursor groups (referred to as D below)
FWD_ANA_BETA_ZERO	2D + 2	Analog estimator of physical delayed neutron fractions (number of delayed neutrons emitted in fission): total, group-wise
FWD_ANA_LAMBDA	2D + 2	Analog estimator of delayed neutron precursor decay constants: total, group-wise

Adjoint-weighted using Meulekamp's method

Parameter	Size	Description
ADJ_MEULEKAMP_BETA_EFF	2D + 2	Adjoint-weighted effective delayed neutron fractions using Meulekamp's method: total, group-wise
ADJ_MEULEKAMP_LAMBDA	2D + 2	Adjoint-weighted of delayed neutron precursor decay constants using Meulekamp's method: total, group-wise

Adjoint weighted time constants using Nauchi's method

Parameter	Size	Description
IFP_CHAIN_LENGTH	1	Number of generations within the iterated fission probability method
ADJ_NAUCHI_GEN_TIME	6	Adjoint-weighted neutron generation times using Nauchi's method: total, prompt, delayed
ADJ_NAUCHI_LIFETIME	6	Adjoint-weighted neutron lifetimes using Nauchi's method: total, prompt, delayed.
ADJ_NAUCHI_BETA_EFF	2D + 2	Adjoint-weighted effective delayed neutron fractions using Nauchi's method: total, group-wise
ADJ_NAUCHI_LAMBDA	2D + 2	Adjoint-weighed of delayed neutron precursor decay constants using Nauchi's method: total, group-wise

Adjoint weighted time constants using IFP

Parameter	Size	Description
ADJ_IFP_GEN_TIME	6	Adjoint-weighted neutron generation times using the iterated fission probability method: total, prompt, delayed
ADJ_IFP_LIFETIME	6	Adjoint-weighted neutron lifetimes using the iterated fission probability method: total, prompt, delayed
ADJ_IFP_IMP_BETA_EFF	2D + 2	Implicit estimator of adjoint-weighted effective delayed neutron fractions using the iterated fission probability method: total, group-wise
ADJ_IFP_IMP_LAMBDA	2D + 2	Implicit estimator of adjoint-weighted of delayed neutron precursor decay constants using the iterated fission probability method: total, group-wise
ADJ_IFP_ANA_BETA_EFF	2D + 2	Analog estimator of adjoint-weighted effective delayed neutron fractions using the iterated fission probability method: total, group-wise
ADJ_IFP_ANA_LAMBDA	2D + 2	Analog estimator of adjoint-weighted of delayed neutron precursor decay constants using the iterated fission probability method: total, group-wise
ADJ_IFP_ROSSI_ALPHA	2	Adjoint-weighted Rossi alpha using the iterated fission probability method

Adjoint weighted time constants using perturbation technique

Parameter	Size	Description
ADJ_PERT_GEN_TIME	2	Adjoint-weighted neutron generation time using the perturbation technique
ADJ_PERT_LIFETIME	2	Adjoint-weighted neutron lifetime using the perturbation technique
ADJ_PERT_BETA_EFF	2	Adjoint-weighted effective delayed neutron fraction using the perturbation technique
ADJ_PERT_ROSSI_ALPHA	2	Adjoint-weighted Rossi alpha using the perturbation technique

Inverse neutron speed

Parameter	Size	Description
ANA_INV_SPD	2	Analog estimate of inverse neutron speed

Analog slowing-down and thermal neutron lifetime (total/prompt/delayed)

Parameter	Size	Description
ANA_SLOW_TIME	6	Analog estimate of slowing-down time: total, prompt, delayed
ANA_THERM_TIME	6	Analog estimate of thermal neutron lifetime: total, prompt, delayed
ANA_THERM_FRAC	6	Analog estimate of neutron thermalisation fraction: total, prompt, delayed
ANA_DELAYED_EMTIME	2	Analog estimate of delayed neutron emission time
ANA_MEAN_NCOL	4	Analog estimate of average number of collisions per history: total and to fission

Dynamic simulation

Parameter	Size	Description
DYN_NB	1	Number of time intervals defined in the time-bin structure (see tme card)
DYN_TMIN	1	Minimum time boundary defined in the time-bin structure (see tme card)
DYN_TMAX	1	Maximum time boundary defined in the time-bin structure (see tme card)
DYN_TIMES	2T + 2	Time-bin boundaries defined in the time-bin structure (see tme card)
DYN_POP	2T	Neutron population at the end of the time interval
DYN_PERIOD	2T	Reactor period based on increase/decrease of neutron population during time interval

Analog mean photon lifetime

Parameter	Size	Description
ANA_LIFETIME	2	Analog estimator of photon lifetime

Homogenized group constants

Notes:

• Group constants are calculated by first homogenizing the geometry using a multi-group structure with H energy groups. The data is then collapsed into the final few-group structure with G groups using the infinite and leakage-corrected flux spectra.
• The methodology used in Serpent for spatial homogenization is described in a paper published in Annals of Nuclear Energy in 2016.
• The fundamental mode calculation is off by default, and invoked by the set fum option. Otherwise all values with B1 prefix are printed as zeros.
• The intermediate multi-group structure is defined using option set micro or set fum.
• The few-group structure is defined using option set nfg.
• The universes in which the group constants are calculated are listed in option set gcu. The calculation is performed for root universe 0 by default, and can be switched off with "set gcu -1".
• If data is produced in multiple universes within a single run, the data is assigned with different run indexes (idx)
• The parameter names can be listed in the set coefpara option, and they will be included in the group constant output file when the automated burnup sequence is invoked.
• The order in which two-dimensional data (scattering matrices, ADF and pin-power parameters) is printed in the [input].coe output file is different from what is listed below in update 2.1.24 and earlier versions.

Common parameters

Parameter	Size	Description
GC_UNIVERSE_NAME	(string)	Name of the universe where spatial homogenization was performed
MICRO_NG	1	Number of energy groups in the intermediate multi-group structure (referred to as H below)
MICRO_E	H + 1	Group boundaries in the intermediate multi-group structure (in ascending order)
MACRO_NG	1	Number of energy groups in the final few-group structure (referred to as G below)
MACRO_E	G + 1	Group boundaries in the final few-group structure (in descending order)

Group constants homogenized in infinite spectrum

Parameter	Size	Description
INF_MICRO_FLX	2H	Multi-group flux spectrum (integral, un-normalized)
INF_FLX	2G	Few-group flux (integral, normalized)
INF_KINF	2	Infinite multiplication factor

Reaction cross sections

Parameter	Size	Description
INF_TOT	2G	Total cross section
INF_CAPT	2G	Capture cross section
INF_FISS	2G	Fission cross section
INF_NSF	2G	Fission neutron production cross section
INF_KAPPA	2G	Average deposited fission energy (MeV)
INF_INVV	2G	Inverse neutron speed (s/cm)
INF_NUBAR	2G	Average neutron yield
INF_ABS	2G	Absorption cross section (capture + fission)
INF_REMXS	2G	Removal cross section (group-removal + absorption)
INF_RABSXS	2G	Reduced absorption cross section (total - scattering production)

Fission spectra

Parameter	Size	Description
INF_CHIT	2G	Fission spectrum (total)
INF_CHIP	2G	Fission spectrum (prompt neutrons)
INF_CHID	2G	Fission spectrum (delayed neutrons)

Scattering cross sections

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.

Parameter	Size	Description
INF_SCATT0	2G	Total P0 scattering cross section
INF_SCATT1	2G	Total P1 scattering cross section
INF_SCATT2	2G	Total P2 scattering cross section
INF_SCATT3	2G	Total P3 scattering cross section
INF_SCATT4	2G	Total P4 scattering cross section
INF_SCATT5	2G	Total P5 scattering cross section
INF_SCATT6	2G	Total P6 scattering cross section
INF_SCATT7	2G	Total P7 scattering cross section
INF_SCATTP0	2G	Total P0 scattering production cross section
INF_SCATTP1	2G	Total P1 scattering production cross section
INF_SCATTP2	2G	Total P2 scattering production cross section
INF_SCATTP3	2G	Total P3 scattering production cross section
INF_SCATTP4	2G	Total P4 scattering production cross section
INF_SCATTP5	2G	Total P5 scattering production cross section
INF_SCATTP6	2G	Total P6 scattering production cross section
INF_SCATTP7	2G	Total P7 scattering production cross section

Scattering matrices

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.
• The order of values ([input].coe) or value pairs ([input]_res.m) is: $\Sigma_{1,1} \, \Sigma_{1,2} \, ... \, \Sigma_{2,1} \, \Sigma_{2,2} \, ...$ where $\Sigma_{g,g'}$ refers to scattering from group g to g'.
• The data in the [input]_res.m file can be read into a G × G matrix with Matlab reshape-command, for example:

reshape(INF_S0(idx,1:2:end), G, G);

Parameter	Size	Description
INF_S0	2G2	P0 scattering matrix
INF_S1	2G2	P1 scattering matrix
INF_S2	2G2	P2 scattering matrix
INF_S3	2G2	P3 scattering matrix
INF_S4	2G2	P4 scattering matrix
INF_S5	2G2	P5 scattering matrix
INF_S6	2G2	P6 scattering matrix
INF_S7	2G2	P7 scattering matrix
INF_SP0	2G2	P0 scattering production matrix
INF_SP1	2G2	P1 scattering production matrix
INF_SP2	2G2	P2 scattering production matrix
INF_SP3	2G2	P3 scattering production matrix
INF_SP4	2G2	P4 scattering production matrix
INF_SP5	2G2	P5 scattering production matrix
INF_SP6	2G2	P6 scattering production matrix
INF_SP7	2G2	P7 scattering production matrix

Diffusion parameters

Notes:

• Calculation of sensible values for INF_TRANSPXS and INF_DIFFCOEF requires fine enough intermediate multi-group structure.
• The cumulative migration method (CMM) was first developed for the OpenMC code.
• CMM diffusion coefficients and transport cross sections are reasonable only when they are calculated over entire geometry (homogenized region covers the entire geometry and is surrounded by periodic or reflective boundary conditions). This means that e.g. pin cell CMM diffusion coefficients can not be calculated from a 2D fuel assembly calculation.
• Calculation of TRC_TRANSPXS and TRC_DIFFCOEF requires defining energy-dependent correction factors using the set trc option.
• Calculation of CMM_TRANSPXS and CMM_DIFFCOEF requires that their calculation is not switched off using the set cmm option.

Parameter	Size	Description
INF_TRANSPXS	2G	Transport cross section (calculated using the out-scattering approximation)
INF_DIFFCOEF	2G	Diffusion coefficient (calculated using the out-scattering approximation)
CMM_TRANSPXS	2G	Transport cross section calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_TRANSPXS_X	2G	X-component of the directional transport cross section calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_TRANSPXS_Y	2G	Y-component of the directional transport cross section calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_TRANSPXS_Z	2G	Z-component of the directional transport cross section calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_DIFFCOEF	2G	Diffusion coefficient calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_DIFFCOEF_X	2G	X-component of the directional diffusion coefficient calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_DIFFCOEF_Y	2G	Y-component of the directional diffusion coefficient calculated using the cumulative migration method (equivalent with the in-scattering approximation)
CMM_DIFFCOEF_Z	2G	Z-component of the directional diffusion coefficient calculated using the cumulative migration method (equivalent with the in-scattering approximation)
TRC_TRANSPXS	2G	Transport cross section calculated by applying user-defined transport correction factors to total cross section
TRC_DIFFCOEF	2G	Diffusion coefficient calculated by applying user-defined transport correction factors to total cross section

Poison cross sections

Notes:

• Printed only if poison cross section option is on (see set poi).
• Xe-135m values printed only if separate treatment of Xe-135m is on (see set poi).
• Approximate effective treatment of Pm-149 production from Pm-148 and Pm-148m is not included in Pm-149 fission yield.
• All values for I-135, Pm-147, Pm-148 and Pm-148m not present in all versions.

Parameter	Size	Description
INF_I135_YIELD	2G	Fission yield of I-135 (cumulative, includes all precursors)
INF_XE135_YIELD	2G	Fission yield of Xe-135
INF_XE135M_YIELD	2G	Fission yield of Xe-135m
INF_PM149_YIELD	2G	Fission yield of Pm-149 (cumulative, includes all precursors)
INF_SM149_YIELD	2G	Fission yield of Sm-149
INF_I135_MICRO_ABS	2G	Microscopic absorption cross section of I-135
INF_XE135_MICRO_ABS	2G	Microscopic absorption cross section of Xe-135
INF_XE135M_MICRO_ABS	2G	Microscopic absorption cross section of Xe-135m
INF_PM147_MICRO_ABS	2G	Microscopic absorption cross section of Pm-147
INF_PM148_MICRO_ABS	2G	Microscopic absorption cross section of Pm-148
INF_PM148M_MICRO_ABS	2G	Microscopic absorption cross section of Pm-148m
INF_PM149_MICRO_ABS	2G	Microscopic absorption cross section of Pm-149
INF_SM149_MICRO_ABS	2G	Microscopic absorption cross section of Sm-149
INF_I135_MACRO_ABS	2G	Macroscopic absorption cross section of I-135
INF_XE135_MACRO_ABS	2G	Macroscopic absorption cross section of Xe-135
INF_XE135M_MACRO_ABS	2G	Macroscopic absorption cross section of Xe-135m
INF_PM147_MACRO_ABS	2G	Macroscopic absorption cross section of Pm-147
INF_PM148_MACRO_ABS	2G	Macroscopic absorption cross section of Pm-148
INF_PM148M_MACRO_ABS	2G	Macroscopic absorption cross section of Pm-148M
INF_PM149_MACRO_ABS	2G	Macroscopic absorption cross section of Pm-149
INF_SM149_MACRO_ABS	2G	Macroscopic absorption cross section of Sm-149

Poison universe-averaged densities

Notes:

• The universe-averaged atomic density is defined to be such that ADENS*MICRO_ABS is equal to MACRO_ABS.

Parameter	Size	Description
I135_ADENS	2	Universe-averaged atomic density of I-135
XE135_ADENS	2	Universe-averaged atomic density of Xe-135
XE135M_ADENS	2	Universe-averaged atomic density of Xe-135m
PM147_ADENS	2	Universe-averaged atomic density of Pm-147
PM148_ADENS	2	Universe-averaged atomic density of Pm-147
PM148M_ADENS	2	Universe-averaged atomic density of Pm-148m
PM149_ADENS	2	Universe-averaged atomic density of Pm-149

Poison decay constants

Parameter	Size	Description
PM147_LAMBDA	1	Decay constant of Pm-147
PM148_LAMBDA	1	Decay constant of Pm-147
PM148M_LAMBDA	1	Decay constant of Pm-148m
PM149_LAMBDA	1	Decay constant of Pm-149
I135_LAMBDA	1	Decay constant of I-135
XE135_LAMBDA	1	Decay constant of Xe-135
XE135M_LAMBDA	1	Decay constant of Xe-135m
I135_BR	1	Branching ratio of I-135 decay to Xe-135. Branching ratio of I-135 decay to Xe-135m is (1 - I135_BR).

Group constants homogenized in leakage-corrected spectrum

Parameter	Size	Description
B1_MICRO_FLX	2H	Multi-group flux spectrum (integral, un-normalized)
B1_FLX	2G	Few-group flux (integral, normalized)
B1_KINF	2	Infinite multiplication factor
B1_KEFF	2	Effective multiplication factor
B1_B2	2	Critical buckling
B1_ERR	2	Absolute deviation of keff from unity

Reaction cross sections

Parameter	Size	Description
B1_TOT	2G	Total cross section
B1_CAPT	2G	Capture cross section
B1_FISS	2G	Fission cross section
B1_NSF	2G	Fission neutron production cross section
B1_KAPPA	2G	Average deposited fission energy (MeV)
B1_INVV	2G	Inverse neutron speed (s/cm)
B1_NUBAR	2G	Average neutron yield
B1_ABS	2G	Absorption cross section (capture + fission)
B1_REMXS	2G	Removal cross section (group-removal + absorption)
B1_RABSXS	2G	Reduced absorption cross section (total - scattering production)

Fission spectra

Parameter	Size	Description
B1_CHIT	2G	Fission spectrum (total)
B1_CHIP	2G	Fission spectrum (prompt neutrons)
B1_CHID	2G	Fission spectrum (delayed neutrons)

Scattering cross sections

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.

Parameter	Size	Description
B1_SCATT0	2G	Total P0 scattering cross section
B1_SCATT1	2G	Total P1 scattering cross section
B1_SCATT2	2G	Total P2 scattering cross section
B1_SCATT3	2G	Total P3 scattering cross section
B1_SCATT4	2G	Total P4 scattering cross section
B1_SCATT5	2G	Total P5 scattering cross section
B1_SCATT6	2G	Total P6 scattering cross section
B1_SCATT7	2G	Total P7 scattering cross section
B1_SCATTP0	2G	Total P0 scattering production cross section
B1_SCATTP1	2G	Total P1 scattering production cross section
B1_SCATTP2	2G	Total P2 scattering production cross section
B1_SCATTP3	2G	Total P3 scattering production cross section
B1_SCATTP4	2G	Total P4 scattering production cross section
B1_SCATTP5	2G	Total P5 scattering production cross section
B1_SCATTP6	2G	Total P6 scattering production cross section
B1_SCATTP7	2G	Total P7 scattering production cross section

Scattering matrices

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.
• The order of values ([input].coe) or value pairs ([input]_res.m) is: $\Sigma_{1,1} \, \Sigma_{1,2} \, ... \, \Sigma_{2,1} \, \Sigma_{2,2} \, ...$ where $\Sigma_{g,g'}$ refers to scattering from group g to g'.
• The data in the [input]_res.m file can be read into a G × G matrix with Matlab reshape-command, for example:

reshape(B1_S0(idx,1:2:end), G, G).

Parameter	Size	Description
B1_S0	2G2	P0 scattering matrix
B1_S1	2G2	P1 scattering matrix
B1_S2	2G2	P2 scattering matrix
B1_S3	2G2	P3 scattering matrix
B1_S4	2G2	P4 scattering matrix
B1_S5	2G2	P5 scattering matrix
B1_S6	2G2	P6 scattering matrix
B1_S7	2G2	P7 scattering matrix
B1_SP0	2G2	P0 scattering production matrix
B1_SP1	2G2	P1 scattering production matrix
B1_SP2	2G2	P2 scattering production matrix
B1_SP3	2G2	P3 scattering production matrix
B1_SP4	2G2	P4 scattering production matrix
B1_SP5	2G2	P5 scattering production matrix
B1_SP6	2G2	P6 scattering production matrix
B1_SP7	2G2	P7 scattering production matrix

Diffusion parameters

Parameter	Size	Description
B1_TRANSPXS	2G	Transport cross section (outscattering transport cross section collapsed with the critical spectrum when old B1 calculation mode is used, otherwise calculated from B1_DIFFCOEF)
B1_DIFFCOEF	2G	Diffusion coefficient calculated from during the fundamental mode calculation (old and new B1 and P1 calculation modes, or flux collapsed during the FM calculation mode)

Poison cross sections

Notes:

• Printed only if poison cross section option is on (see set poi).
• Xe-135m values printed only if separate treatment of Xe-135m is on (see set poi).

Parameter	Size	Description
B1_I135_YIELD	2G	Fission yield of I-135 (cumulative, includes all precursors)
B1_XE135_YIELD	2G	Fission yield of Xe-135
B1_XE135M_YIELD	2G	Fission yield of Xe-135m
B1_PM149_YIELD	2G	Fission yield of Pm-149 (cumulative, includes all precursors)
B1_SM149_YIELD	2G	Fission yield of Sm-149
B1_I135_MICRO_ABS	2G	Microscopic absorption cross section of I-135
B1_XE135_MICRO_ABS	2G	Microscopic absorption cross section of Xe-135
B1_XE135M_MICRO_ABS	2G	Microscopic absorption cross section of Xe-135m
B1_PM149_MICRO_ABS	2G	Microscopic absorption cross section of Pm-149
B1_SM149_MICRO_ABS	2G	Microscopic absorption cross section of Sm-149
B1_XE135_MACRO_ABS	2G	Macroscopic absorption cross section of Xe-135
B1_XE135M_MACRO_ABS	2G	Macroscopic absorption cross section of Xe-135m
B1_SM149_MACRO_ABS	2G	Macroscopic absorption cross section of Sm-149

Delayed neutron data

Notes:

• The output consists of total, followed by D precursor group-wise values. In earlier versions, the output was fixed to 9 values independently of the library in use, with zero values corresponding to the empty precursor groups in the library.
• The actual number of groups depends on the cross section library used in the calculations. JEFF-3.1, JEFF.3.2 and later evaluations use 8 precursor groups, while earlier evaluations, as well as all ENDF/B and JENDL data is based on 6 groups.

Parameter	Size	Description
BETA_EFF	2D + 2	Effective delayed neutron fraction (currently calculated using the Meulekamp method)
LAMBDA	2D + 2	Decay constants

Assembly discontinuity factors

Notes:

• Calculation of assembly discontinuity factors requires the set adf option.
• Surface flux and current tallies are used to calculate the boundary currents and fluxes. Mid-point and corner values are approximated by integrating over a small surface segment.
• The surface and volume fluxes are flux densities, i.e. they are surface or volume integrated fluxes divided by the respective surface area or volume.
• The currents are surface integrated values.
• The net current is defined as current in subtracted with current out.
• When the homogenized region is surrounded by reflective boundary conditions (zero net-current) the homogeneous flux becomes flat and equal to the volume-averaged heterogeneous flux. When the net currents are non-zero, the homogeneous flux is obtained using the Built-in diffusion flux solver.
• The calculation currently supports only a limited number of surface types: infinite planes and square and hexagonal prisms.
• The order of surface and mid-point values for square prisms is: $X_{\mathrm{W},1} \, X_{\mathrm{W},2} \, ... \, X_{\mathrm{S},1} \, X_{\mathrm{S},2} \, ... \, X_{\mathrm{E},1} \, X_{\mathrm{E},2} \, ... \, X_{\mathrm{N},1} \, X_{\mathrm{N},2} \, ...$ and the order of corner values: $X_{\mathrm{NW},1} \, X_{\mathrm{NW},2} \, ... \, X_{\mathrm{NE},1} \, X_{\mathrm{NE},2} \, ... \, X_{\mathrm{SE},1} \, X_{\mathrm{SE},2} \, ... \, X_{\mathrm{SW},1} \, X_{\mathrm{SW},2} \, ...$ where $X_{k,g}$ refers to parameter $X$ on surface/corner k and energy group g.
• The order of surface values for Y-type hexagonal prims runs clockwise starting from the north, i.e. N, NE, SE, S, SW, NW. The corner values run counterclockwise starting from east, i.e. E, NE, NW, W, SW, SE.
• The order of surface values for X-type hexagonal prims runs counterclockwise starting from the east, i.e. E, NE, NW, W, SW, SE. The corner values run clockwise starting from north, i.e. N, NE, SE, S, SW, NW.
• The sign moment weighted parameters are calculated only for surface types sqc, rect and hexxc.
• The convention of sign moment directions follows that of the nodal neutronics program Ants.
• The ADF symmetry options on set adf card are currently not used for sign moment weighted parameters.

Parameter	Size	Description
DF_SURFACE	(string)	Name of the surface used for the calculation
DF_SURFACE_TYPE	1	Surface type
DF_SURFACE_N_PARAMS	1	Number of parameters defining the surface
DF_SURFACE_PARAMS	NP	List of parameters defining the surface
DF_SYM	1	Symmetry option defined in the input
DF_N_SURF	1	Number of surface values (denoted as NS below)
DF_N_CORN	1	Number of corner values (denoted as NC below)
DF_VOLUME	1	Volume (3D) or cross sectional area (2D) of the homogenized cell
DF_SURF_AREA	NS	Area (3D) or perimeter length (2D) of the surface region
DF_MID_AREA	NS	Area (3D) or perimeter length (2D) of the mid-point region
DF_CORN_AREA	NC	Area (3D) or perimeter length (2D) of the corner region
DF_SURF_IN_CURR	2G × NS	Inward surface currents
DF_SURF_OUT_CURR	2G × NS	Outward surface currents
DF_SURF_NET_CURR	2G × NS	Net surface currents
DF_MID_IN_CURR	2G × NS	Inward mid-point currents
DF_MID_OUT_CURR	2G × NS	Outward mid-point currents
DF_MID_NET_CURR	2G × NS	Net mid-point currents
DF_CORN_IN_CURR	2G × NC	Inward corner currents
DF_CORN_OUT_CURR	2G × NC	Outward corner currents
DF_CORN_NET_CURR	2G × NC	Net corner currents
DF_HET_VOL_FLUX	2G	Heterogeneous flux over homogenized cell
DF_HET_SURF_FLUX	2G × NS	Heterogeneous surface fluxes
DF_HET_CORN_FLUX	2G × NC	Heterogeneous corner fluxes
DF_HOM_VOL_FLUX	2G	Homogeneous flux over homogenized cell
DF_HOM_SURF_FLUX	2G × NS	Homogeneous surface fluxes
DF_HOM_CORN_FLUX	2G × NC	Homogeneous corner fluxes
DF_SURF_DF	2G × NS	Surface discontinuity factors
DF_CORN_DF	2G × NC	Corner discontinuity factors
DF_SGN_SURF_IN_CURR	2G × NS	Inward sign moment weighted currents
DF_SGN_SURF_OUT_CURR	2G × NS	Outward sign moment weighted currents
DF_SGN_SURF_NET_CURR	2G × NS	Net sign moment weighted currents
DF_SGN_HET_SURF_FLUX	2G × NS	Heterogeneous sign moment weighted surface fluxes
DF_SGN_HOM_SURF_FLUX	2G × NS	Homogeneous sign moment weighted surface fluxes
DF_SGN_SURF_DF	2G × NS	Sign moment weighted surface discontinuity factors

Pin-power form factors

Notes:

• Calculation of pin-power form factors requires the set ppw option.
• The power distribution is calculated by tallying the few-group fission energy deposition in each lattice position and dividing the values with the total energy produced in the universe (sum over all values of PPW_POW equals 1).
• The calculation of form factors depends on the boundary conditions:
  1. If the homogenized region is surrounded by reflective boundary conditions (zero net-current), the homogeneous flux becomes flat and equal to the volume-averaged heterogeneous flux.
  2. When the net currents are non-zero, the homogeneous flux is obtained using the built-in diffusion flux solver. The form-factors (PPW_FF) are obtained by dividing the pin- and group-wise powers with the corresponding homogeneous diffusion flux (PPW_HOM_FLUX).
  3. However, if the net currents are non-zero, but the sum of the net currents is equal to zero, the volume-averaged heterogeneous flux is used as the homogeneous flux, which is not an accurate approximation. This case is for example when modeling hexagonal fuel assemblies with other than 30 or 60 degree symmetries with periodic boundary conditions.
• Running the diffusion flux solver currently requires ADF calculation.
• The order of values is: $X_{1,1} \, X_{1,2} \, ... \, X_{2,1} \, X_{2,2} \, ...$ where $X_{n,g}$ refers to parameter $X$ of pin n and energy group g. For example, two-group power distributions in a 17 x 17 lattice can be converted into matrix form using the reshape-command in Matlab:

P1 = reshape(PPW_POW(1, 1:4:end), 17, 17);
P2 = reshape(PPW_POW(1, 3:4:end), 17, 17);

• Symmetry used in the lattice may result in some pin powers and form factors to be for example 1/2, 1/4 or 1/8 of their true value, which have to be corrected during post processing of the values.

Parameter	Size	Description
PPW_LATTICE	(string)	Name of the lattice used for the calculation
PPW_LATTICE_TYPE	1	Lattice type (corresponds to the lat-card)
PPW_PINS	1	Number of pin positions in the lattice (denoted as NP below)
PPW_POW	2G × NP	Pin- and group-wise power distribution normalized to unity sum
PPW_HOM_FLUX	2G × NP	Pin- and group-wise homogeneous flux distribution
PPW_FF	2G × NP	Pin- and group-wise form factors

Albedos

Notes:

• Calculation of albedos requires the set alb option.
• The order of the surfaces should be the same as for the ADFs.
• The order of ALB_IN_CURR is $J_{1,1} , J_{1,2} , \ldots , J_{2,1} , J_{2,2} , \ldots$ where $J_{k,g}$ refers to incoming partial current of surface k of group g.
• The order of ALB_OUT_CURR is $J_{1,1,1,1} , J_{1,1,1,2} , \ldots , J_{1,1,2,1} , J_{1,1,2,2} , \ldots , J_{1,2,1,1} , J_{1,2,1,2} , \ldots , J_{2,1,1,1} , J_{2,1,1,2} , \ldots$ where $J_{k,g,k',g'}$ refers to outgoing partial current of surface k' of group g' which has entered the albedo surface through surface k and group g.
• The order of ALB_TOT_ALB is $\alpha_{1,1} , \alpha_{1,2} , \ldots , \alpha_{2,1} , \alpha_{2,2} , \ldots$ where $\alpha_{g,g'}$ refers to albedo from group g to g'.
• The order of ALB_PART_ALB is $\alpha_{1,1,1,1} , \alpha_{1,1,1,2} , \ldots , \alpha_{1,1,2,1} , \alpha_{1,1,2,2} , \ldots , \alpha_{1,2,1,1} , \alpha_{1,2,1,2} , \ldots , \alpha_{2,1,1,1} , \alpha_{2,1,1,2} , \ldots$ where $\alpha_{k,g,k',g'}$ refers to albedo of surface k' of group g' which has entered the albedo surface through surface k and group g.
• For example, two-group hexagonal partial albedos can be converted into matrix form using the reshape-command in Matlab with the notation part_alb(g', k', g, k) $= \alpha_{k,g,k',g'}$ as

part_alb = reshape(ALB_PART_ALB(1, 1:2:end), 2, 6, 2, 6)

Parameter	Size	Description
ALB_SURFACE	(string)	Name of the surface used for the calculation
ALB_FLIP_DIR	1
ALB_N_SURF	1	Number of albedo surface faces (denoted as NS below)
ALB_IN_CURR	2G × NS	Groupwise incoming partial currents of albedo surface faces
ALB_OUT_CURR	2G2 × NS2	Outgoing group to group and face to face outgoing partial currents
ALB_TOT_ALB	2G2	Total group to group albedos for the entire albedo surface
ALB_PART_ALB	2G2 × NS2	Partial group to group and face to face albedos