Difference between revisions of "Output parameters"

Revision as of 16:40, 23 September 2016

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

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 B₁ leakage-corrected flux spectra.
• The B₁ calculation is off by default, and invoked by the set fum option.
• The intermediate multi-group structure is defined using option set micro.
• 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 .coef output is different from what is listed below in update 2.1.24 and earlier versions.

Common parameters

Group constants homogenized in infinite spectrum

Reaction cross sections

Fission spectra

Scattering cross sections

Notes:

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

Scattering matrices

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.
• The order of values (.coe) or value pairs (_res.m) is: where refers to scattering from group g to g'.
• The data in the _res.m file can be read into a G by G matrix with Matlab reshape-command, for example: reshape(INF_S0(idx,1:2:end), G, G).

Diffusion parameters

Notes:

• The cumulative migration method was first developed for the [OpenMC] code.^[1] The method works only when the homogenized region covers the entire geometry, and is surrounded by periodic or reflective boundary conditions.

Poison cross sections

Notes:

• Printed only if poison cross section option is on (see set poi).

Group constants homogenized in B₁ leakage-corrected spectrum

Reaction cross sections

Fission spectra

Scattering cross sections

Notes:

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

Scattering matrices

Notes:

• Scattering production includes multiplying (n,2n), (n,3n), etc. reactions.
• The order of values (.coe) or value pairs (_res.m) is: where refers to scattering from group g to g'.
• The data in the _res.m file can be read into a G by G matrix with Matlab reshape-command, for example: reshape(B1_S0(idx,1:2:end), G, G).

Diffusion parameters

Poison cross sections

Notes:

• Printed only if poison cross section option is on (see set poi).

Delayed neutron data

Notes:

• The output always consists of 9 values: total, followed by precursor group-wise values. If the number of groups is 6, the last two values are zero.
• 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.

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.
• Fluxes and currents are normalized average values.
• 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: and the order of corner values: where refers to parameter on surface/corner k and energy group g.
• The order of surface and mid-point values for hexagonal prims runs clockwise starting from the north (Y-type) or east (X-type) face. The corner values start from the next corner in clockwise direction.
• Note to developers: the description may be wrong for for X-type hexagonal prism.

Parameter	Size	Description
DF_SURFACE	(string)	Name of the surface used for the calculation
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	NS	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 flux
DF_HET_CORN_FLUX	2G NC	Heterogeneous corner flux
DF_HOM_VOL_FLUX	2G	Homogeneous flux over homogenized cell
DF_HOM_SURF_FLUX	2G NC	Homogeneous surface flux
DF_HOM_CORN_FLUX	2G NC	Homogeneous corner flux
DF_SURF_DF	2G NC	Surface discontinuity factors
DF_CORN_DF	2G NC	Corner discontinuity factors