Polaris: 2D Light Water Reactor Lattice Physics Module¶
M. A. Jessee, J. J. Jarrell, W. A. Wieselquist, M. L. Williams, K. S. Kim, T. M. Evans, S. P. Hamilton, C. A. Gentry
Polaris is a new module for SCALE 6.2 that provides 2D lattice physics analysis capability for light water reactor (LWR) fuel designs. Polaris uses a new multigroup self-shielding method called the Embedded Self Shielding Method (ESSM) and a new transport solver based on the Method of Characteristics (MoC). The ESSM computes multigroup self-shielded cross sections using Bondarenko interpolation methods. The background cross section used in the interpolation is determined by iterative 2D MoC fixed source transport calculations. Polaris is integrated with ORIGEN for depletion calculations. Each pin—or each radial subregion of the pin—is depleted based on the local power distribution. An optional critical spectrum calculation is incorporated into the depletion calculation and the output edits of few-group homogenized cross sections. Few-group cross sections are archived to an xfile016 file, which can be used in subsequent core simulator calculations. Polaris provides an easy-to-use input format to allow users to set up lattice models with minimal lines of input.
Acknowledgments
The authors express gratitude to Brad Rearden and Stephen Bowman for their supervision of Polaris development for the US Nuclear Regulatory Commission (NRC). The author acknowledges Don Algama and Mourad Aissa of the NRC for their support of the project. Appreciation is extended to the ATLAS development team—Jordan Lefebvre, Rob Lefebvre, and Adam Thompson—for their development of the ATLAS Ray Tracing Geometry package used in the Polaris MoC solver. Appreciation is also extended to Ugur Mertyurek, Brian Ade, Ben Betzler, Scott Palmtag, and Andrew Godfrey for testing and benchmarking efforts and also Sheila Walker for finalizing the publication of this document.
Introduction¶
Polaris is a new module for SCALE 6.2 that provides 2D lattice physics analysis capability for light water reactor (LWR) fuel designs. For multigroup cross section processing, Polaris uses the Embedded Self-Shielding Method (ESSM) [WK12]. Unlike SCALE multigroup sequences that use XSProc, ESSM does not require user-defined unit cell definitions. ESSM computes multigroup cross sections using Bondarenko interpolation methods. The background cross section used in the interpolation is determined by iterative 2D fixed source transport calculations. Both the ESSM fixed source calculations and the keff calculation utilize a new Method of Characteristics (MoC) transport solver developed in the Exnihilo computational package.
Polaris is integrated with ORIGEN for depletion calculations. Each pin—or each radial subregion of the pin—is depleted based on the local power distribution. An optional critical spectrum calculation is incorporated into the depletion calculation and the output edits of few-group homogenized cross sections. Few-group cross sections are archived to an xfile016 file, which can be used in subsequent core simulator calculations. A complete description of the Polaris computational methods is provided in [JWE+14].
Polaris provides an easy-to-use input format to allow users to set up lattice models with minimal lines of input. All recognized Polaris commands are shown in Table 1. Note that many commands support short and long forms. The allowed basic Types for input are described in Table 2. The special Polaris TYPES are shown in Table 3. The convention used in this manual is that basic types appear italicized and capitalized (Type), while special Polaris types appear in all caps (TYPE).
card |
long command |
short command(s) |
---|---|---|
system |
system |
sys |
geometry |
geometry |
geom |
composition |
composition |
comp |
property |
property |
prop |
material |
material |
mat |
burnup |
bu or dbu |
|
power |
power |
pow |
options |
option |
opt |
time |
t or dt |
|
state |
state |
|
branch block |
branch |
|
pin geometry component |
pin |
|
assembly pin map |
pinmap |
|
assembly channel |
channel |
|
assembly half gap |
hgap |
|
channel box |
box |
|
shield |
shield |
|
deplete |
deplete |
|
slab geometry component |
slab |
|
power basis materials |
basis |
|
assembly inserts |
insert |
|
assembly control elements |
control |
basic Type |
description |
examples |
incorrect examples |
---|---|---|---|
Word |
starts with a character A-Z or a-z and includes characters, numbers, underscores |
uox bor_water_500pp m FUEL |
uox_enr5.1 316SS
uox-3.1
|
Int |
integer |
17 92235 2 565 |
31.4 uox |
Bool |
boolean/logical |
yes false |
TRUE No |
Real |
any number |
565 10.257 1.5e-6 |
yes bor_water |
String |
a single or double quoted string |
“INFMED” “Includes spaces” ‘NONE’ |
Includes spaces |
Value |
any non-word |
Int|Bool|Real|String |
Polaris Type |
description |
Variants |
---|---|---|
STYPE |
system type |
PWR|BWR |
GTYPE |
geometry type |
ASSM|REFL |
CTYPE |
composition type |
NUM|WT|FORM|CONC|LW|UOX |
PTYPE |
property type |
SOLP |
ETYPE |
control element type |
RODLET |
OTYPE |
option type |
KEFF|BOND|ESSM|CRITS PEC|FG|* DEPL*|RUN|PRINT |
The Polaris input supports a very flexible input scheme that allows some elements to be suppressed for better readability. With key=value type input, when the standard order of keys is used, the keys may be suppressed. Consider the following input specification as an example.
geometry GNAME : ASSM npins=Int ppitch=Real [sym=FULL|SE]
The geometry card requires a geometry name (GNAME) in the first group, then a geometry type (GTYPE) which is ASSM here indicating an assembly geometry. The remaining arguments have keys: “npins” with an integer value, “ppitch” with a real value, and the optional “sym” with either FULL or SE values (optional arguments are always shown in square brackets: [sym=*FULL*|SE]. The default value is underlined: (FULL). The pipe “|” shows an or relation i.e., FULL or SE is an acceptable value).
geometry FuelNode : ASSM npins=15 ppitch=1.43 sym=FULL
geometry FuelNode : ASSM 15 1.43 FULL
geometry FuelNode : ASSM sym=FULL ppitch=1.43 npins=15
geometry FuelNode : ASSM 15 1.43
geometry FuelNode ASSM 15 1.43
The group separator “:” is suppressed in the last variant. This is possible in any situation where (1) the group is implicitly terminated by running out of arguments or (2) the next type does not match the expected type in the current group. For example, consider the hgap card:
hgap [ d ] [: M ]
In this card, d and M are values (without keys) defined as Real and material name (MNAME), respectively. The following form would automatically bypass the Real value, which allows a default, and set the interassembly gap material name as COOL.2.
hgap COOL.2
Setup¶
The cards in this section generally appear at the beginning of an input file. Note that the manual is organized with each card starting a new page. This is especially convenient when printing a few cards across different sections.
title – case title lines¶
title Line1 Line2 … Linei … LineN
param |
type |
name |
details |
default |
Linei |
String |
line |
used in output file headers |
“DEFAULT TITLE” |
Examples:
title "Westinghouse 15x15"
title "Westinghouse 15x15"
"Condition: Hot Full Power"
"Date: 10/18/2012"
Comments:
The title card gives a title to this Polaris case, which appears as a descriptive header on the output file. The additional lines may be used to document a subcase or to embed additional information in the output file in an orderly way (e.g., author, date, project identifier).
The title card is optional.
See also:
lib
library – nuclear data libraries¶
lib [mg=*String*]
param |
type |
name |
details |
default |
mg |
String |
multigroup library |
multigroup cross section library |
“fine_n” |
Examples:
% a name of library in the DATA directory
% use SCALE 252g ENDF/B-VII.1 library
lib "fine_n" % SAME AS "V7-252"
% use SCALE 56g ENDF/B-VII.1 library
lib mg="broad_n" % SAME AS mg="V7-56"
% a name of a local library in the temporary working directory
% (useful in SAMPLER calculations)
lib "perturbed_xs_library"
% fully specified path
lib "C:\scale6.2\data\scale.rev04.xn252v7.1"
Comments:
The lib card specifies the multigroup library location. See SCALE’s FileNameAliases.txt file in the installation directory for up-to-date library aliases for the fine and broad group libraries provided in SCALE’s data directory. Only the 252-group and the 56-group cross section libraries can be used in Polaris. Full specification of the file path is acceptable, as in the final example shown above.
The lib card is optional.
See also:
title
Geometry¶
The highest level structures in the model are named and defined with a geometry card. The general outline for a geometry definition is shown below. Two types of geometry are currently supported, ASSM for pressurized water reactor (PWR) or boiling water reactor (BWR) assemblies with fuel elements in a square-pitch, and REFL for an assembly-adjacent reflector.
geom GNAME : GTYPE arguments
argument |
type |
name |
details |
default |
GNAME |
Word |
geometry name |
||
GTYPE |
- |
geometry type |
||
ASSM |
assembly |
see pin & pinmap |
||
REFL |
reflector |
see slab |
||
arguments |
remaining arguments |
depends on GTYPE |
The control element geometry is also enumerated with types, as shown below. To model PWR-type rod cluster control assemblies (RCCAs), the RODLET element type is used in conjunction with pin definitions. In future releases of Polaris, other control element types, such as BWR-type control blades will be supported.
control INAME : ETYPE arguments
Argument |
type |
name |
details |
default |
INAME |
Word |
control element name |
||
ETYPE |
- |
control element type |
||
RODLET |
PWR-type RCCA |
requires PINIDs |
||
arguments |
remaining arguments |
depends on ETYPE |
For accurate solutions to lattice physics problems using the method of characteristics (MoC), the input geometry must be subdivided into smaller regions called cells. Although the defaults should be applicable in most cases, the capability to change the number of cells is provided through meshing options appearing at the end of many geometry cards. See the slab, pin, box, and hgap cards for details.
geometry<ASSM> – assembly¶
- geom GNAME :
ASSMnpins=Intppitch=Real[sym=*FULL|SE*]
param |
type |
name |
details |
default |
GNAME |
Word |
assembly name |
||
GTYPE |
ASSM |
|||
npins |
Int |
number of pins |
on each side of the assembly |
|
ppitch |
Real |
pin pitch |
units: cm |
|
sym |
FULL|SE |
symmetry |
assembly symmetry FULL: no symmetry SE: south-east quarter |
FULL |
Examples:
% simple pincell
geom MyPin : ASSM 1 1.5
% 17x17 Westinghouse with 1.26 cm pin pitch in quarter symmetry
geom FuelNode : ASSM 17 1.26 sym=SE
Comments:
The assembly geometry describes the basic elements of an assembly. The pin and pinmap cards are required to finalize the assembly geometry. The hgap card specifies the interassembly half gap, and the channel specifies the channel material for the assembly.
See also:
pinmap, pin, hgap, box, channel, control, insert
geometry<REFL> – reflector¶
- geom GNAME :
- REFLthick=REAL
param |
type |
name |
details |
default |
GNAME |
Word |
reflector name |
||
GTYPE |
REFL |
|||
thick |
Real |
thickness |
units: cm |
Examples:
% defines a 20 cm reflector
geom ReflectorNode : REFL 20.0
Comments:
The reflector geometry describes the basic elements of a simple slab-type reflector. The slab card can be used to define geometric dimensions and mesh for the reflector geometry.
See also:
slab
channel – materials and mesh options¶
channel [Mchan =MCLASS]
param |
type |
name |
details |
default |
Mchan |
MCLASS |
material class |
initializes materials in outermost pin zone |
* |
*By default, Mchan will be set to COOL by “system PWR” and “system BWR.” Otherwise, Mchan is required. |
Examples:
% define the channel material class to be COOL
channel COOL
Comments:
The channel card is used to set the default channel material class for the outermost region of each pin, typically containing reactor coolant. See the material card for a description of material classes.
See also:
pin, material, geometry<ASSM>
hgap – half distance between assemblies¶
- hgap
- [ dE dN dW dS ][: ME MN MW MS ][: nfE nfN nfW nfS ][: ndE ndN ndW ndS ]
param |
type |
name |
details |
default |
di |
Real |
list of widths with i: E: east N: north W: west S: south |
accepts 1, 2, or 4 values E: all hgaps are same E+N: dE =dS and dN =dW units: cm |
0.0 |
Mi |
MNAME |
list of material names |
requires same # as di |
* |
meshing options |
||||
nfi |
Int |
list of number of faces per pin |
requires same # as di |
2 |
ndi |
Int |
list of number of divisions |
requires same # as di |
1 |
*By default, hgap material will be set to COOL.1 by “system PWR.” For “system BWR,” the east and south hgap materials will be set to MOD.2, and the west and north hgap materials will be set to MOD.1. Otherwise hgap material is required.
Examples:
% defines a 17x17 Westinghouse assembly with 1.26 cm pin pitch
% with 0.04 cm half-gap filled with material COOL.1
geom w17x17 : ASSM 17 1.26 sym=SE
hgap 0.04 COOL.1
% defines a GE 7x7 assembly with 1.88 cm pin pitch
% 0.48 cm narrow gap on east and south edge
% 0.95 cm wide gap on north and west edge
% narrow gap mesh is 3
% wide gap mesh is 4
% faces per pin is 2 for both narrow and wide gap
geom ge7x7 : ASSM 7 1.88
hgap 0.48 0.95 : MOD.1 MOD.1 : 2 2 : 3 4
Comments:
The hgap specifies the outermost geometry region in an assembly. If a channel box exists, then hgap specifies the material and mesh from outer channel box edge to the problem boundary. Otherwise, hgap specifies the material and mesh from the edge of the fuel array to the problem boundary. In both cases, hgap represents the half-distance between adjacent assemblies for single assembly calculations. Fig. 1 shows some of the hgap meshing options. Referring to the south edge of the assembly, the number of faces per pin refers to the extra cells introduced by “splitting” the pin cell boundary, and the number of divisions refers to extra horizontal lines dividing half gap into smaller width cells.
See also:
pinmap, control, insert, geometry<ASSM>, channel, box

Fig. 1 Interassembly half gap meshing variants.¶
box [thick=*Real*] [rad=*Real*] [icdist=*Real*] [xrad=*Real*] [xlen=*Real*] [Mbox=MNAME]
param |
type |
name |
details |
default |
thick |
Real |
nominal thickness (cm) |
must be >0 |
none |
rad |
Real |
inner corner radius (cm) |
must be >0, additional constraints listed below |
none |
icdist |
Real |
in-channel distance (cm) |
must be >0 |
none |
xrad |
Real |
extra corner thickness (cm) |
must be >= 0 |
0 |
xlen |
Real |
extra corner length (cm) |
excludes rounded corner length |
0 |
Mbox |
MNAME |
box material |
* |
*By default, box material will be set to CAN.1 by “system BWR.” Otherwise box material is required.
Examples:
% GE 7x7 assembly with 1.88 cm pin pitch
% 0.48 cm narrow gap
% 0.95 cm wide gap
system BWR
geom ge7x7 : ASSM 7 1.88
hgap 0.48 0.95
% Box geometry
% 0.2 thickness
% 0.97 inner corner radius
% 0.14 in-channel distance
box 0.2 0.97 0.14
% Same example, all variables
box 0.2 0.97 0.14 0 0 CAN.1
Comments:
The box specifies the channel box geometry and material that surround the array of fuel pins.
Fig. 2 and Fig. 3 show different box geometries, with and without thick corners respectively.

Fig. 2 Box geometry example (uniform thickness).¶

Fig. 3 Box geometry example (thick corners).¶
pin – pin or pincell¶
param
type
name
details
default
PINID
- Word|
Int
pin identifier
size
Int
pin will be placed in a size x size pincell grid
used to create large water rods in CE PWRs and GE BWRs (see pinmap)
ri
Real
list of
radii
for each radial zone from center out
units: cm
Mi
MNAME
list of
pin materials
material in each radial zone
.1 added if given MCLASS, e.g., FUELFUEL.1
Mout
MNAME
material
in outermost zone
material in outermost zone
.1 added if given MCLASS, e.g., FUELFUEL.1
*
meshing options
nsect
Int
number of sectors
azimuthal sections of the pin cell, value applies to all nsi
and nso ut
nring
Int
number of rings
value applies to all nri
and nrout
nri
Int
number of rings
number of rings in each radial zone
1
nrout
Int
number of rings
in outermost zone
number of rings in the outermost zone
1
nsi
Int
number of sectors
number of sectors in each radial zone
1
nsout
Int
number of sectors
in outermost zone
number of sectors in the outermost zone
1
*If not specified, the material class MCLASS is taken from the channel card (Mchan) and set to the first member of that class, “Mchan.1.” For example if Mchan=“COOL,” then Mout= “COOL.1.”
Examples:
%standard fuel pin
pin 1 : 0.4096 0.418 0.475
: FUEL GAS CLAD
%empty guide tube
pin E : 0.561 0.602
: COOL.1 CLAD.1
%pyrex
pin P : 0.214 0.231 0.241 0.427 0.437 0.484 0.561 0.602
: GAS TUBE GAS BP.3 GAS TUBE COOL CLAD
%standard fuel pin with explicit material in the outermost region
pin 1 : 0.4096 0.418 0.475
: FUEL GAS CLAD COOL.6
%standard fuel pin with explicit ring and sector mesh
pin 1 : 0.4096 0.418 0.475
: FUEL GAS CLAD
: 5 1 1 0 %5 rings in fuel
: 8 1 1 1 %8 sectors only in fuel
%large central 2x2 water rod in 4x4 assembly
pin W size=2 : 0.8
: COOL
%pinmap must show adjacent Ws
pinmap
F F F F
F W W F
F W W F
F F F F
Comments:
The pin card is one of the basic building blocks of the assembly model. It is the only geometry component which allows an integer (Int) identifier as well as a Word—all other geometric identifiers use Word. Note that the materials are required, except for the last Mout, which can be used to overwrite the material given by a channel for the outermost region in the pincell. The various pin cell meshing options are displayed in Fig. 3.2.4. Note that extra rings in the radial zones create equal area regions, whereas rings in the outermost region create equal distance divisions between the last radius and the pincell boundary. Extra sectors create additional azimuthal divisions. A negative value of sectors is allowed and can be used to rotate the sector mesh by a half angle, e.g., ns=4 looks like ⊕ and ns=-4 looks like ⊗.
The total number of cells used in the transport calculation is determined from both the number of rings and the number of sectors. With the MoC transport solver, the fidelity of the solution is also dictated by the number of azimuthal and polar angles and ray spacing. These parameters are changed on the option<KEFF> card.
Due to self-shielding and depletion, each cell could be modeled as a unique material with its own cross section data. However, this is prohibitively memory intensive and typically not necessary. The shield card provides the mechanism to control the additional self-shielded materials introduced.
See also:
pinmap, control, insert, channel, system, option<KEFF>, shield

Fig. 4 Pincell meshing variants.¶
pinmap – pin layout¶
- pinmap
- PINID1PINID2 …PINIDi … PINIDN
param
type
name
details
default
PINIDi
- Word|
Int
list of
pin identifiers
supports full, quarter, or octant symmetry
quarter: assumes southeast (SE)
octant: assumes south-by-so utheast (SSE)
Examples:
%Westinghouse 17x17 pinmap in octant symmetry
pinmap
2
1 1
1 1 1
3 1 1 3
1 1 1 1 1
1 1 1 1 1 3
3 1 1 3 1 1 1
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
%Westinghouse 17x17 pinmap in quarter symmetry
pinmap
2 1 1 3 1 1 3 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
3 1 1 3 1 1 3 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 3 1 1 1
3 1 1 3 1 1 1 1 1
1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1
%Westinghouse 17x17 pinmap in full
pinmap
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 3 1 1 3 1 1 3 1 1 1 1 1
1 1 1 3 1 1 1 1 1 1 1 1 1 3 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 3 1 1 3 1 1 3 1 1 3 1 1 3 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 3 1 1 3 1 1 2 1 1 3 1 1 3 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 3 1 1 3 1 1 3 1 1 3 1 1 3 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 3 1 1 1 1 1 1 1 1 1 3 1 1 1
1 1 1 1 1 3 1 1 3 1 1 3 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
%large central 2x2 water rod in 6x6 assembly
%pinmap must show adjacent Ws
pin W size=2 : 0.8
: COOL
pinmap
F F F F F F
F F F F F F
F F W W F F
F F W W F F
F F F F F F
F F F F F F
Comments:
The pinmap card defines the layout of pin cells in the assembly. The symmetry is determined by the number of pin identifiers given on the card and must not be more general than the symmetry option given on the assembly geometry card (i.e., do not define a full pin map for a sym=SE assembly model).. If the pin has a large size specifier, size>1, then the pinmap must reflect that with those pins occurring in blocks of size × size.
See also:
geometry<REFL> – reflector , control, insert
control<RODLET> – RCCA-type layout¶
|control INAME : RODLET | PINID1 | PINID2 … | PINIDi … PINIDN
param |
type |
name |
details |
default |
INAME |
Word |
insert name |
||
ETYPE |
RODLET |
|||
PINIDi |
|
list of pin identifiers |
same format as pinmap “_” indicate empty locations |
Examples:
% B4C control rods
mat GAS.1 : FILLGAS
mat CLAD.1 : ZIRC4
mat MOD.1 : LW
mat TUBE.1 : SS304
mat CNTL.1 : B4C
pin B : 0.214 0.231 0.241 0.427 0.437 0.484 0.561 0.602
: GAS TUBE GAS CNTL GAS TUBE MOD CLAD
control BankD : RODLET
_
_ _
_ _ _
B _ _ B
_ _ _ _ _
_ _ _ _ _ B
B _ _ B _ _ _
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _
Comments:
Note that control elements and inserts share the INAME identifiers, so an insert and a control element cannot have the same name. Different control rod banks may be included in a single input file using more than one control card with unique INAMEs. The main difference between the inserts defined by control element and insert cards is that by default, control element materials are not depleted, whereas insert materials are depleted.
The outer dimensions of the tube must be included in the pin card that is inserted.
See also:
pinmap, control, insert, state
insert – insert layout¶
param |
type |
name |
details |
default |
INAME |
Word |
insert name |
||
PINIDi |
|
list of pin identifiers |
same format as pinmap “_” indicate empty locations |
Examples:
%pyrex inserts
pin P : 0.214 0.231 0.241 0.427 0.437 0.484 0.561 0.602
: GAS TUBE GAS BP.3 GAS TUBE COOL CLAD
insert PyrexInserts :
_
_ _
_ _ _
P _ _ P
_ _ _ _ _
_ _ _ _ _ P
P _ _ P _ _ _
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _
Comments:
The insert card defines a set of pins to be used to model inserts such as WABA. When the insert is “in,” the insert pins replace overlapping regions of the pins defined on the assembly pinmap. An underscore (_) is used to indicate locations without inserts. See the notes on the control<RODLET> card for additional guidelines.
See also:
pinmap, control, insert
slab – slab geometry¶
param |
type |
name |
details |
default |
SLABID |
Word |
slab geometry identifier |
reflector GNAME |
|
ti |
Real |
list of slab thicknesses |
units: cm |
|
Mi |
MNAME |
list of material names |
||
meshing options |
||||
nxi |
Int |
list of number of x-divisions |
1 |
|
nyi |
Int |
list of number of y-divisions |
1 |
Examples:
% a reflector definition
% 2.22 cm of baffle
% 15 cm of moderator
geom ReflectorNode : REFL 17.22
slab 2.22 15 : BAFFLE.1 MOD.1
Comments:
The slab card may be used to define three things: (1) the materials and thicknesses of a reflector initiated on a geometry card, (2) slabs in a control blade, and (3) spacer grids. If the first argument identifier is not present, then the first purpose of describing the various material thicknesses in a reflector is assumed. The meshing options allow each material slab to be spatially refined in x and y, increasing the number of cells in the transport problem. The meshing option for the number of x divisions creates the equivalent of additional “sub-slabs” in each user-defined slab thickness. The y-divisions create additional cells vertically. The default of one y-division corresponds to the entire assembly.
See also:
geometry<REFL>
Materials¶
A material contains two main types of information: (1) the composition, or distribution of nuclides, and (2) the properties which include basic (required) properties like density and temperature, and as well as (optional) properties like soluble poison content, void, or grid spacer smearing. The composition is defined by a composition card. The basic specification for a material is shown below.
mat MNAME : CNAME [dens=*Real*] [temp=*Real*] [: properties]
argument |
type |
name |
details |
default |
MNAME= MCLASS.MSUB |
Word.Int |
material name |
used to reference this material |
|
CNAME |
Word |
composition name |
||
dens |
Real |
density |
basic property units: g/cm3 |
composition reference density, if defined |
temp |
Real |
temperature |
basic property units: K |
293 |
properties |
Word=Value |
properties |
extra properties are defined with property cards |
no extra properties |
A material name has two parts, the material class, or MCLASS, and a member identifier, or MSUB. For example, FUEL.2 has an MCLASS=FUEL and an MSUB=2. All properties are defined by MCLASS. The composition referenced by CNAME is created with a composition card, as shown below.
comp CNAME : CTYPE arguments
argument |
type |
Name |
details |
default |
CNAME |
Word |
composition name |
used to reference this composition later in materials and property definitions |
|
CTYPE |
- |
composition type |
||
General Composition Constructor s <#basis-power-basis-materials>__ |
||||
NUM |
number fraction |
|||
WT |
weight fraction |
|||
FORM |
Formula |
|||
CONC |
Concentrations |
|||
LW |
borated light water |
|||
UOX |
uranium oxide fuel |
|||
arguments |
remaining arguments |
depends on CTYPE |
Additional properties are defined with the property card, which defines the property PNAME for a material class MCLASS. The property type, PTYPE, determines the remaining arguments.
prop PNAME MCLASS : PTYPE arguments
argument |
type |
name |
details |
default |
PNAME |
Word |
property name |
used to reference this property |
|
PTYPE |
PTYPE |
property type |
||
SOLP |
soluble poison |
used to define soluble boron content |
||
arguments |
remaining arguments |
depends on PTYPE |
material – material¶
argument
type
name
details
default
MNAME
Word.Int
material name
uses form MCLASS.MSUB
CNAME
Word
composition name
dens
Real
density
basic property
units: g/cm3
composition
reference density
temp
Real
temperature
basic property
units: K
293
pi =vali
PNAME=Value
properties
additional properties
0
Examples:
% define a gas gap material
mat GAP.1 : FILLGAS
% define a 3.5% enriched fuel material
comp uox_e350 : UOX 3.5
mat FUEL.1 : uox_e350 dens=10.257 temp=900
% define a cladding material
mat CLAD.1 : ZIRC4
% define a guide tube material
mat TUBE.1 : SS304
% define a control rod material
mat CNTL.1 : AIC
Comments:
Material properties may be set on either a material card or on a state card. If a temperature is specified rather than a density, the “temp=” key must be used to skip over the density argument.
See also:
state, composition, property
composition<NUM|WT> – general atom/wt fraction¶
param
type
name
details
default
CNAME
Word
composition name
CTYPE
NUM
number fraction
WT
weight fraction
scale
PCT|ABS|PP M
scaling factor
all values are divided by this factor PCT: percentage
(divide by 100) PPM: parts per million (divide by 1e6)
ABS: absolute (divide by 1)
PCT
norm
Bool
normalize
normalize values to 1
false
refdens
Real
reference density
default density for materials using this composition
units: g/cm3
*
structure
Function
structure
see Table X.X.X
FREE
idi =vali
Word|Int=Real
id/value pairs
value<0 fills the remainder up to value
see acceptable id forms below
*The density property must be defined for each material either explicitly on the material card itself or implicitly through the “reference density” of the material’s composition.
Examples:
% create a plutonium vector and then plutonium oxide
comp puvec : WT scale=PCT
Pu238=1.2
Pu239=63.3
Pu240=21.0
Pu241=8.6
Pu242=5.9
comp puox : FORM puvec=1 O=2
% create an 85/10/5 Ag/In/Cd composition
% using 10% In, 5% Cd,
% and filling the remainder up to 100% with Ag
comp aic : WT In=10 Cd=5 Ag=-100
Comments:
IDs in weight or number fraction-based compositions may be any of the following:
nuclide IDs (Int), e.g., 92235,
nuclide names (Word), e.g., U235 or u235,
element Z numbers (Int), e.g., 92,
element names (Word), e.g., U or u, or
other composition names (CNAME).
See also:
composition<FORM>
composition<FORM> – general chemical formula¶
comp CNAME : FORM * [refdens=*Real]
param |
Type |
name |
details |
default |
CNAME |
Word |
composition name |
||
CTYPE |
FORM |
formula |
||
refdens |
Real |
reference density |
default density for materials using this composition units: g/cm3 |
* |
structure |
Function |
structure |
see Table X.X.X |
FREE |
idi =vali |
Word|Int=Real |
id/value pairs |
see acceptable id forms below values in atoms per molecule (e.g., H2 O is given as “H”=2 “O”=1) |
*The density property must be defined for each material either explicitly on the material card itself or implicitly through the “reference density” of the material’s composition.
Examples:
% define Gd2O3 using element names
% (using elements implies natural abundances used in isotopics)
comp gd2o3 : FORM Gd=2 O=3
% define Gd2O3 using 100% Gd 155
comp gd2o3 : FORM Gd155=2 O=3
% define D2O using nuclide IDs and element names
comp d2o : FORM 1002=2 8000=3
comp d2o : FORM H2=2 O=3
Comments:
IDs in formula-based composition may be any of the following:
nuclide IDs (Int), e.g., 92235,
nuclide names (Word), e.g., U235 or u235,
element Z numbers (Int), e.g., 92,
element names (Word), e.g., U or u, or
other composition names (CNAME).
See also:
composition<NUM|WT>, composition<CONC>
composition<CONC> – general number density¶
param
type
name
details
default
CNAME
Word
composition name
CTYPE
CONC
concentration
refdens
Real
reference density
default density for materials using this composition
units: g/cm3
**
idi =vali
Int=Real
id/value pairs
see acceptable id forms below
note: cannot use other CNAMEs for IDs in CONC input
units: #/barn-cm
**A reference density is automatically calculated from concentrations input. If specified, it will simply scale up concentrations linearly.
Examples:
% pyrex composition
comp pyrex_e125 : CONC
5010=9.63266E-04
5011=3.90172E-03
8016=4.67761E-02
14028=1.81980E-02
14029=9.24474E-04
14030=6.10133E-04
% fuel composition
comp uox_e310_gd180 : CONC
92234=3.18096E-06
92235=3.90500E-04
92236=1.79300E-06
92238=2.10299E-02
64152=3.35960E-06
64154=3.66190E-05
64155=2.48606E-04
64156=3.43849E-04
64157=2.62884E-04
64158=4.17255E-04
64160=3.67198E-04
8016=4.53705E-02
% wet annular burnable absorber (WABA) composition
comp waba : CONC
5010=2.98553E-03
5011=1.21192E-02
6000=3.77001E-03
8016=5.85563E-02
13027=3.90223E-02
Comments:
IDs in concentration-based composition may be any of the following:
nuclide IDs (Int), e.g., 92235;
nuclide names (Word), e.g., U235 or u235;
element Z numbers (Int), e.g., 92;
element names (Word), e.g., U or u; and
SCALE-specific Nuclide IDs (Int), e.g., 3006000 (Only available for comp(CONC) card).
Other composition names (CNAME) cannot be used in a concentration definition. To easily ensure consistency of input when comparing codes, the composition input should be used in the concentrations described here. In all other cases, the other composition constructors are recommended because they are much simpler and easier to use.
See also:
composition<FORM>, composition<NUM|WT>
composition<LW> – borated light water¶
comp CNAME : LW [borppm=*Real*] [refdens=*Real*]
param |
Type |
name |
details |
default |
CNAME |
Word |
composition name |
||
CTYPE |
LW |
light water |
||
borppm |
Real |
boron |
parts per million by weight of natural boron (B) in light water (H2 O) |
* |
refdens |
Real |
reference density |
default density for materials using this composition units: g/cm3 |
0.0 |
*The density property must be defined for each material either explicitly on the material card itself or implicitly through the “reference density” of the material’s composition.
Examples:
% define a 600ppm boron moderator composition
comp mod_600ppm : LW 600
% same composition using FORM and WT
comp mod : FORM H=2 O=1
comp mod_600ppm : WT scale=PPM norm=yes
mod=1e6 B=600
Comments:
Internally, the borated light water composition is built from composition<FORM> and composition<WT> cards assuming natural boron. To use different boron isotopics such as depleted or enriched boron, the more general composition cards should be used.
See also:
composition<FORM>, composition<WT>
composition<UOX> –UO2 fuel¶
comp CNAME : UOX enr=Real [bu=*Real*] [refdens=*Real*]
param |
type |
name |
details |
default |
CNAME |
Word |
composition name |
||
CTYPE |
UOX |
uranium dioxide |
||
enr |
Real |
enrichment |
U-235 wt. % (see composition<ENRU> for formula) |
|
bu |
Real |
burnup |
only available for 0≤bu≤100 units: GWd/MTU |
0* |
refdens |
Real |
reference density |
default density for materials using this composition units: g/cm3 |
** |
*Generally, the burnup parameter should not be specified. It is provided for testing purposes only to create a fixed, representative, burned fuel composition. The composition is interpolated using linear interpolation from an internal burnup- and enrichment-dependent data matrix.
**The density property must be defined for each material either explicitly on the material card itself or implicitly through the “reference density” of the material’s composition.
Examples:
% define a 4.95% enriched fuel composition with a reference density
comp uox_495 : UOX 4.95 refdens=10.25
% same result as above
comp u_495 : ENRU 4.95
comp uox_495 : FORM u_495=1 O=2
Comments:
Internally, the UO2 composition is built from composition<FORM> and composition<ENRU> cards.
See also:
composition<ENRU>, composition<FORM>
composition<ENRU> – enriched uranium¶
comp CNAME : ENRU enr=Real [refdens=*Real*]
param |
type |
name |
details |
default |
CNAME |
Word |
composition name |
||
CTYPE |
UOX |
uranium dioxide |
||
enr |
Real |
enrichment |
*U-235 wt.% |
|
refdens |
Real |
reference density |
default density for materials using this composition units: g/cm3 |
** |
*The following formula from [BS96] is used to determine the 234U and 236U wt% from the 235U enrichment. Note that this formula is only valid for U-235 enrichments less than 10 wt%.wu234 = 0.007731*(enr) 1.0837wu236 = 0.0046*enrwu238 = 100 – wu234 – enr – wu236**The density property must be defined for each material either explicitly on the material card itself or implicitly through the “reference density” of the material’s composition.
Examples:
% 5% enriched metal fuel
comp umetal : ENRU 5
Comments:
This composition for enriched uranium is used internally to create UO2 using the composition<UOX> card.
See also:
composition<UOX>
Standard molecular compositions
CNAME |
Description |
---|---|
H2O B4C Er2O3 Gd2O3 SiC ZrH Zr5H8 ZrH2 fillgas |
light water with structure=BOND(H2O) Boron carbide burnable poison material Erbium oxide burnable poison material Gadolinium oxide burnable poison material Silicon carbide zirconium hydride alloy with structure=CRYS(orthorhombic_zrh) zirconium hydride alloy with structure=CRYS(cubic_zrh) zirconium hydride alloy with structure=CRYS(tetragonal_zrh) Helium gas |
Standard reactor mixtures and alloys
CNAME |
Description |
---|---|
aic pyrex zirc2 zirc4 ss304 ss316 inc718 water |
Ag-In-Cd control rod absorber material Pyrex glass Zircaloy-2 clad material Zircaloy-4 clad material Stainless Steel 304 Stainless Steel 316 Inconel 718 H2O with trace amount of boron |
pyroc |
Pyrolytic carbon, C with structure=CRYS(pyrolytic_c) |
graphite |
Graphite, C with structure=CRYS(hexagonal_c) |
Structure names
structure |
Description |
Nuclide ** Cross section** ID |
---|---|---|
BOND(H2O) |
H,O in liquid water |
H-1→1001 H-2→1002 |
FREE |
atoms allowed to orient freely (no structure) |
H-1→8001001 H-2→8001002 |
CRYS(orthorhombic_zrh) |
Zr,H in zirconium hydride alloy with orthorhombic crystal structure (gamma phase) |
H-1→7001001 Zr-90→1040090 Zr-91→1040091 Zr-92→1040092 Zr-93→1040093 Zr-94→1040094 Zr-95→1040095 Zr-95→1040096 |
CRYS(cubic_zrh) |
Zr,H in zirconium hydride alloy with cubic crystal structure (delta phase) |
H-1→7001001 Zr-90→1040090 Zr-91→1040091 Zr-92→1040092 Zr-93→1040093 Zr-94→1040094 Zr-95→1040095 Zr-95→1040096 |
CRYS(tetragonal_zrh) |
Zr,H in zirconium hydride alloy with tetragonal crystal structure (epsilon phase) |
H-1→7001001 Zr-90→1040090 Zr-91→1040091 Zr-92→1040092 Zr-93→1040093 Zr-94→1040094 Zr-95→1040095 Zr-95→1040096 |
CRYS(pyrolytic_c) |
C in pyrolytic crystal structure (graphite) |
C→3006000 |
CRYS(hexagonal_c) |
C in pyrolytic carbon (additional covalent bonds compared to graphite) |
C→3006000 |
*Note: the cross section IDs can only be used on composition cards with the CONC variant to input number densities directly.
property<SOLP> – soluble poison by weight¶
prop PNAME M1 … : SOLP poison [scale=PPM|PCT|ABS]
param |
Type |
name |
details |
default |
PNAME |
Word |
property name |
property value p≥ 0 |
|
M1 … |
MCLASS |
material class |
one or more material classes to gain this property |
|
PTYPE |
SOLP |
soluble poison |
||
poison |
CNAME |
soluble poison composition name |
||
scale |
PCT|ABS|PP M |
scaling factor |
ABS: absolute (divide by 1) |
PPM |
Examples:
% define a soluble boron property for moderator
% and coolant material classes
% using natural boron
prop boron MOD COOL : SOLP B
% investigate coolant crud/impurity activation
% 1. define a general impurity property to mix in coolant,
comp crud : NUM Ni=12.7 Cr=2.3 Fe=-100 %mostly Fe
prop impurity COOL : SOLP crud
% 2. create coolant material with 100ppm of crud
mat COOL.1 : LW dens=0.75 : impurity=100
% 3. make sure to "deplete" coolant so crud gets activated
deplete COOL=true
Comments:
None
See also:
pinmap, control, insert
deplete – material depletion and decay¶
deplete M1=Bool M2=Bool … Mi=Bool … MN=Bool
param |
type |
name |
details |
default |
Mi |
MNAME|MCLAS S |
list of material names or material classes |
use ALL for all materials |
Note
Only one deplete card is allowed in an input.
Note
ALL only applies in the first position
Examples:
% turn on depletion/decay for two new materials
sys PWR
deplete MyMaterial=true MyOtherMaterial=true
% activate/deplete/decay every material
deplete ALL=true
% impose strict conditions
sys PWR
deplete ALL=false FUEL=true CLAD=true
Comments:
The deplete card not only instructs Polaris to deplete a material, but also to solve the Bateman equations with ORIGEN for that material. Thus if the flux/power is zero, only materials that are flagged to “deplete” will undergo decay. The deplete card modifies the depletables included in a system card to avoid the situation in which “deplete MyMaterial=true” would make only MyMaterial depletable. Thus to completely re-specify the depletable materials, “ALL=false” should be used as the first argument. This is in contrast to the basis card, which completely specifies a new power basis.
See also:
material, shield, basis
basis – power basis materials¶
basis M1=Bool M2=Bool … Mi=Bool … MN= Bool
param |
type |
name |
details |
default |
Mi |
MNAME|MCLAS S |
list of material names or material classes |
use ALL for all materials |
ALL |
Note
Only one basis card is allowed per input.
Note
ALL is only allowed in the first position.
% use only FUEL materials as the basis
basis ALL=no FUEL=YES
% Specify FUEL.3 as the basis
basis ALL=no FUEL.3=YES
Comments:
The basis card is used to specify the materials to use in power normalization. By default, the energy release from all materials is taken into account, including (n,gamma) reactions in structural materials such as cladding. It is not recommended to change the default of ALL in most situations. Exceptions include (1) when comparing results to other codes that only use fuel in the basis and (2) fixing the power in a specific pin is known—a material should be created only for that pin, and the power basis should be specified for that material only. The basis card overrides any power basis imposed by a system card. Thus it behaves differently than a deplete card, which is combined with depletable materials imposed by a system card.
See also:
material, shield, deplete
shield – cross section self-shielding expansion specification¶
shield M1=XTYPE M2=XTYPE … Mi=XTYPE … MN= XTYPE
param |
type |
name |
Details |
default |
Mi |
MNAME|MCLAS S |
list of material names or material classes |
use ALL for all materials |
|
XTYPE |
N|P|R|S |
self-shield ing expansion type |
shield across various mesh elements N: no expansion P: pins R: rings (P implicit) |
R |
Note
Only one shield card is allowed per input.
Note
ALL is only allowed in the first position.
Examples:
%create a unique self-shielded FUEL cross sections in each pin
%consider all other materials to have a single self-shielded cross section
shield ALL=N FUEL=P
%assess effect of self-shielding each pin’s cladding
shield CLAD=P
%re-specify self-shielding to be P by default, R for the FUEL
shield ALL=P FUEL=R
Comments:
The shield card controls how materials are internally expanded for self-shielding purposes. By default, Polaris expands all materials across pins and rings (R). For example, a fuel region defined on a pin card as having 10 rings will be expanded internally to have 10 different self-shielded cross sections. Because the R option also implicitly includes the P option, each instance of that pin will also get different cross sections.
When using specific systems (e.g., system PWR), this card is generally not needed. The shield card modifies the self-shielding options included in a system card. Thus, to completely re-specify the expansion, use “ALL=N” as the first argument. This is in contrast to the basis card, which completely specifies a new power basis.
See also:
material, deplete, system
State¶
The idea of a “state” or “statepoint” is a standard concept in lattice physics calculations. In Polaris, the concept of state is mostly tied to the values of material properties. The base state for a calculation is determined as follows:
The base state is initialized with any property values set on material cards.
The base state is updated with any state cards that apply to ALL.
The base state is updated with any other state cards, and the power card is used to set the base state power.
This sequence ensures that the state does not change, even if the order of inputs changes. A time or burnup card is then used to initiate a calculation as a function of time or burnup, thus producing a sequence of states. A branch block is used to perform branches off the base state at specific times or burnups.
state<MNAME> – material state¶
param |
type |
name |
details |
default |
MNAME|MCLAS S |
material name or material class |
use ALL for all materials |
||
pi |
PNAME |
property name |
||
vali |
Value |
property value |
Examples:
% reset to hot zero power conditions
state ALL : temp=565
state COOL : dens=0.75
% set channel/bypass materials to different ppm boron
state COOL : boron=0
state BYP : boron=600
% set all materials with a boron property
state ALL : boron=300
Comments:
The state card declares the base state for materials and the base state of possible control elements or insert elements.
See also: material, deplete, system
state<INAME> – insert/control state¶
state INAME : in=Bool
param |
type |
name |
details |
default |
INAME |
insert name or control element name |
|||
in |
Bool |
insertion |
“in=” is required |
Examples:
% insert bank D control rods
state BankD : in=true
% remove inserts named Ins6A
state Ins6A false
% perform reflector calculation
state ReflectorNode : in=true
Comments:
This form of the state card is required to insert any control element or inserts. By default, inserts and control elements are out when defined.
See also:
material, deplete, system
state<GNAME> – geometry state¶
state GNAME : pres=Bool
param |
type |
name |
details |
default |
GNAME |
geometry name |
|||
pres |
Bool |
present |
“pres=” is required |
Examples:
% disable reflector calculation even though
% reflector geometry is present
state ReflectorNode : pres=false
Comments:
The geometry version of the state card is used to declare which geometric elements are present in the system. The geometry version of the add card is useful for performing branch calculations for reflector nodes. Note that an assembly geometry must be present to perform a calculation.
See also:
geometry<REFL>, state<MNAME>, state<INAME>
power – total power¶
pow [: p1 p2 … pi … pN]
param |
type |
Name |
details |
default |
pi |
Real |
list of specific powers in W/g initial heavy metal |
0 |
Examples:
% set power to 35 W/gIHM
power 35.0
% provide a power history
% must have same number of values as following time/burnup card
power : 35.0 40.0 45.0 45.0 40.0 5.0 0.0
time : 10 20 30 40 50 60 70
Comments:
The power card specifies the total power of the basis materials specified by a basis card. The power value may be specified only once.
See also:
t, bu, history, basis, state<MNAME>
bu – initiate calculation with cumulative burnups¶
bu [units=*GWD/MTIHM*|MWD/MTIHM] : [b1 b2 … bi … bN]
param |
Type |
name |
details |
default |
units |
GWD/MTIHM| MWD/MTIHM |
burnup units |
GWD/MTIHM |
|
bi |
Real |
list of absolute burnups |
0 |
Examples:
% simple depletion case with constant power and absolute/cumulative burnups
power 40
bu 0 5 10 15 20 30 40 50 60 80
% using MWd/MTIHM units with variable power
% 40 W/gIHM for 05000 MWD/MTIHM, then 30 W/gIHM for 500010000 MWD/MTIHM
power 40 30
bu MWD/MTIHM: 0 5000 10000
% combine burn/time cards
% 20 W/gIHM for 05 then 510 GWD/MTIHM steps, then
% 40 W/gIHM for a 5-day step then 30 W/gIHM for a 5-day step
power 20
bu GWD/MTIHM : 5 10 GWD/MTIHM
power 40 30
dt DAYS : 5 5
Comments:
The bu card initiates a calculation for a given sequence of cumulative burnups. A burnup or time card usually follows a power card, the two effectively specifying the power history. If multiple burnups are given, then the power card must have either a single power or a list of powers the same size as the list times. A value of 0 is implicit at the beginning of the first burnup list. Multiple burnup/time cards may be specified in an input. This can be convenient for switching units or changing from burnup-based to time-based depletion. Internal automatic substeps are always in effect unless modified with the option<DEPL> card.
See also:
t, dt, dbu, power, option<DEPL>, branch, deplete
dbu – initiate calculation with incremental burnups¶
dbu [units=*GWD/MTIHM*|MWD/MTIHM] : [b1 b2 … bi … bN]
param |
Type |
name |
details |
default |
units |
GWD/MTIHM| MWD/MTIHM |
burnup units |
GWD/MTIHM |
|
bi |
Real |
list of incremental burnups |
0 |
Examples:
% incremental burnups equivalent to
% power 40
% bu 0 5 10 15 20 30 40 50 60 80
power 40
dbu 5 5 5 5 10 10 10 10 20
Comments:
The dbu card initiates a calculation for a given sequence of incremental burnups. Otherwise, it is identical to the bu card for specifying cumulative burnups.
See also:
t, dt, bu, power, option<DEPL>, branch, deplete
t – initiate calculation by cumulative time¶
t [units=*SECONDS*|MINUTES|HOURS|DAYS|YEARS] : [t1 t2 … ti … tN]
param |
Type |
name |
details |
default |
units |
SECONDS|MINUTE S| HOURS| DAYS|YEARS |
time units |
DAYS |
|
ti |
Real |
list of times |
0 |
0 |
Examples:
% burn with 40 W/gIHM for 300 days in 100-day increments
power 40
t 100 200 300
% simulate 2 cycles of time-dependent irradiation with shutdown cooling
% note that time defaults to DAYs
%
% cycle 1
power 40 30 30 30
t 100 200 300 400
power 0
t 415
%
% cycle 2
power 30 20 20 20
t 515 615 715 815
power 0
t 830
Comments:
The t card initiates a calculation for a given sequence of cumulative/absolute times. One of the time cards (t, dt, or ti) is required to model periods of decay in conjunction with power 0. Otherwise, the time card t is similar in functionality to the burnup bu card but with different units.
See also:
dt, bu, dbu, power, option<DEPL>, branch, deplete
dt – initiate calculation by incremental time¶
dt [units=*SECONDS*|MINUTES|HOURS|DAYS|YEARS] : [t1 t2 … ti … tN]
param |
Type |
name |
details |
default |
units |
SECONDS|MINUTE S| HOURS| DAYS|YEARS |
time units |
DAYS |
|
ti |
Real |
list of times |
0 |
0 |
Examples:
% burn with 40 W/gIHM for 300 days in 100-day increments equivalent to
% power 40
% t 100 200 300
power 40
dt 100 100 100
% decay for 30 minutes
power 0
dt 30 MINUTES
Comments:
The dt card is identical to the cumulative time card t except that the values given are incremental.
See also:
t, bu, dbu, power, option<DEPL>, branch, deplete
branch – instantaneous change¶
param |
type |
Name |
details |
default |
BNAME |
Word |
branch name |
DEFAULT |
|
allowed cards in branch block |
||||
Add |
- |
adds a list of states to branch on |
Examples:
% fuel temperature and boron branches (results in 7 total states) read branch add FUEL : temp=800 1000 1200 add COOL : boron=0 400 800 1400 end branch
% branch to different % fuel temp/coolant temp/coolant density, synchronizing % states (results in 3 total states) read branch
% state 1 2 3
- add FUELtemp=800 1000 1200
COOL : temp=565 585 620
COOL : dens=0.73 0.71 0.68 end branch
Comments:
The branch card initiates so-called “branch” calculations, i.e., instantaneous changes of state at specific burnups/times during the base depletion sequence of calculations. The syntax for the add card is identical to the state card except, instead of taking a list of different properties and their values, it takes a single property and a list of values. Note that a time or burnup card is not necessary—if not found, branches will be performed at every burnup/time specified in the base state. The initial state for any branch card is the base state as specified in the main file. This means branch cards have no knowledge of one another.
See also:
add, bu, t, title
add<MNAME> – material branch¶
param |
type |
name |
details |
default |
MNAME|MCLAS S |
material name or material class |
use ALL for all materials |
||
incr |
Bool |
increment |
values are added to reference value |
false |
scale |
ABS|PCT |
Scaling |
scaling ABS: absolute units PCT: percentage units |
ABS |
PNAME |
property name |
|||
vali |
Value |
list of property values |
Examples:
% fuel temperature branches using incremental
% changes from the base state of 900 K
state FUEL : temp=900
read branch
add FUEL incr=true : temp=-200 -100 +100 +200 +500
end branch
% material properties may be varied together (synchronized)
% by chaining additional material/properties together
% the first block below results in 2 states
% the second is 6 states
read branch
add FUEL : temp=900 1200
FUEL : dens=10.4 10.3
COOL : dens=0.7 0.65
end branch
read branch
add FUEL : temp=900 1200
add FUEL : dens=10.4 10.3
add COOL : dens=0.7 0.65
end branch
Comments:
The add card is only valid inside a branch block. This version adds a set of branches for a specific material name (MNAME) or class (MCLASS). Branches are always with respect to the base state. Although similar to the state card, the add card has a single property name and a list of values. The state card has a list of property=value pairs.
See also:
material, state<MNAME>
add<INAME> – insert/control branch¶
add INAME : in=Bool1[Bool2]
param |
type |
name |
details |
default |
INAME |
insert name or control element name |
|||
in |
Bool |
list of insertion states |
“in=” is required |
Examples:
% branch to remove WABA inserts
state InsWABA4 : in=true
read branch
add InsWABA4 : in=false
end branch
% synchronize rods in with material branches (5 states)
read branch
add BankD : in=true false false false true
FUEL : temp=600 900 1200 2000 2000
end branch
% swap control banks
read branch
add BankB : in=true false false
BankC : in=false true false
BankD : in=false false true
end branch
Comments:
This form of the add card is required to add branches to insert/remove control elements or inserts. Given that only two possible states exist, specifying “true false” will result in a calculation at the other state not specified by the base state.
See also:
insert, control, state<INAME>
add<GNAME> – geometry branch¶
add GNAME : pres=Bool1[Bool2]
param |
type |
name |
details |
default |
GNAME |
geometry name |
|||
pres |
Bool |
list of geometry states |
“pres=” is required |
Examples:
% perform a reflector calculation on a branch
state ReflectorNode : pres=no
read branch
add ReflectorNode : pres=yes
end branch
Comments:
This form of the add card is required to add branches for new geometry, such as reflector calculations. Given that only two possible states exist, specifying “true false” will result in a calculation at the other state not specified by the base state.
See also:
geometry, state<GNAME>
Options¶
An extensive set of options is provided for manipulating the solvers and output. Most option cards support a key=value style of input, with reasonable defaults in place for all parameters.
option<KEFF> – eigenvalue¶
opt KEFF [key1=val1 key2=val2 … keyi=vali … keyN=valN]
Examples:
% change the MOC ray spacing for the
% eigenvalue calculation to 0.01 cm
opt KEFF RaySpacing=0.01
%P3 scattering
opt KEFF PnOrder=3
option<ESSM> – embedded self-shielding¶
opt ESSM
[key1=val1 key2=val2 … keyi=vali … keyN=valN]
Examples:
% change within group solver to use source iterations
opt ESSM WithinGroupSolver=SOURCE
option<BOND> – Bondarenko search¶
opt BOND [key1=val1 key2=val2 … keyi=vali … keyN=valN]
Examples:
% introduce Bondarenko iterations on total cross section
opt BOND
MaxIterations=10
ConvergenceXS="SIGT"
option<DEPL> – depletion¶
opt DEPL [key1=val1 key2=val2 … keyi=vali … keyN=valN]
Examples:
% Set the number of origen substeps per time steps to 2
% (may be useful for convergence studies)
opt DEPL
NumSubsteps=2
% disable the addition of depletion nuclides to input materials
opt DEPL TrackingSet="NONE"
% use CRAM solver
opt DEPL Solver="CRAM"
option<CRITSPEC> – critical spectrum¶
opt CRITSPEC [key1=val1 key2=val2 … keyi=vali … keyN=valN]
Examples:
% enable critical buckling search using B1 equations for a buckling of 1e-3
opt CRITSPEC
Mode="SPECIFIED"
B2=1e-3
Method="B1"
option<PRINT> – printing¶
key |
value type |
details |
default |
---|---|---|---|
XSSummary |
Bool |
print a cross section summary in the output file |
yes |
CritSpecSummary |
String |
print critical spectrum summary “NONE”: no print out “BUCKLING”: limited buckling info “SPECTRUM”: full spectrum |
“BUCKLING” |
XFile16 |
Bool |
output a TRITON xfile016 nodal data library |
no |
InputDataContai ner |
Bool |
print out the input data container |
yes |
InputCompositio nSummary |
Bool |
print compostion card input summary |
yes |
InputMaterialSu mmary |
Bool |
print material card input summary |
yes |
LibrarySummary |
Bool |
print cross section library summary |
no |
MaterialSummary |
Bool |
print material summary at each statepoint |
no |
Examples:
% print the xfile016
% if input file is polaris.inp, file name will be polaris.x16
opt PRINT XFile16=yes
% print summaries
opt PRINT XSSummary=yes
CritSpecSummary="SPECTRUM"
InputCompositionSummary=yes
InputMaterialSummary=yes
LibrarySummary=yes
MaterialSummary=yes % disabled for now
option<FG> – few-group cross section generation¶
- opt FG
- [AdjointMode=String InvVelMode=String][: b1 b2 … bi … bN ][: E1 E2 … Ei … EN-1 ]
param |
type |
details |
default |
---|---|---|---|
AdjointMode |
String |
type of adjoint calculation to use in few-group data generation “INFMED”: infinite medium adjoint “CRITICAL”: critical spectrum adjoint “UNIFORM”: uniform adjoint |
“INFMED” |
InvVelMode |
String |
weighting option for few-group inverse velocities “FORWARD”: forward flux weighting “ADJOINT”: adjoint flux weighting |
“FORWARD” |
bi |
Real |
list of burnups to include in output few-group cross section database, e.g., XFile16 output units: GWd/MTHM |
all burnups available |
Ei |
Real |
note descending order and only N-1 divisions are needed for an N group structure E0 is maximum energy (typically 2e7 eV) EN is minimum (typically 1e-5 eV) units: eV |
0.625 eV division (two groups) |
Examples:
% enable the critical spectrum adjoint
opt FG AdjointMode="CRITICAL"
%only include 0,10,15,20 GWd/MTHM burnups in few-group outputs, including XFile16
opt FG : 0 10 15 20
%redefine group energy divisions for 3 groups with divisions at 10 and 0.625 eV
opt FG : : 10 0.625
option<RUN> – run time¶
opt RUN [key1=val1 key2=val2 … keyi=vali … keyN=valN]
key |
value type |
details |
default |
CheckOnly |
Bool |
check input and terminate |
true |
HomogenizeGrains |
Bool |
homogenize grains |
false |
Examples:
% check input
opt RUN CheckOnly=true
% homogenize grains
opt RUN HomogenizeGrains=yes
See also:
property<GRAIN>
System¶
The system cards provide a way to initialize a set of defaults to simplify input and add robustness for a well-known and well-characterized system.
system STYPE
argument |
Type |
name |
details |
default |
STYPE |
- |
system type |
||
PWR |
pressurized water reactor |
|||
BWR |
boiling water reactor |
The system card performs the following actions:
defines a set of materials and properties, imposing standard names for the materials and properties;
warns user of potential mistakes; and
uses heuristics to modify unspecified mesh and solver options for robust results.
system<PWR> – pressurized water reactor¶
sys PWR
Definitions
Description
Twelve reactor materials are initialized with compositions and densities from the predefined composition set. In most cases, all that remains is to define fuel materials, all material temperatures, and properties such as COOL/MOD soluble boron and density. Note that some rules are based on naming conventions. For example, burnable poisons (the material class BP) are declared to be depletable materials, whereas the CNTL (control elements) class of materials is not.
Examples:
% a complete input file for a PWR pincell model
=polaris
system PWR
geom MyPin : ASSM 1 1.5
comp f35 : UOX 3.5
mat FUEL.1 : f35 dens=10.25
pin 1 : 0.5 0.6 : FUEL CLAD
state ALL : temp=565
state MOD : dens=0.743
state COOL: dens=0.743
state ALL : boron=600
power 40
burn 0 0.1 0.2 0.5 1 2 5 10 15
20 25 30 35 40 45 50 55 60
end
Sample problems¶
Within the SCALE distribution, 27 Polaris sample problems are provided to demonstrate the differences in calculation and geometry options, and 21 sample problems consider the Consortium for Advanced Simulation of Light Water Reactors (CASL) Virtual Environment for Reactor Applications (VERA) benchmark problems for pin cell and lattice configurations described in [God14]. The VERA pin cell problems are identified as polaris_1a_252g.inp through polaris_1e_252g.inp. The VERA lattice problems are identified as polaris_2a_252g.inp through polaris_2k_252g.inp, polaris_2l_56g.inp through polaris_2m_56g.inp, polaris_2o_252g.inp, and polaris_2p_252g.inp.
The remaining six sample problems are described as follows:
polaris_TMI1_Cycle1-2.inp – 15 × 15 PWR geometry model with branch block definition for lattice physics calculations
polaris_bench_taka3_sf97-4_assm.inp, polaris_bench_taka3_sf97-4_pin.inp - Takahama UOX depletion benchmark for radiochemical assay NT3G24-SF97-4 described in [RE13].
polaris_bwr10x10.inp, polaris_bwr7 × 7.inp – example BWR geometry models for 10 × 10 and 7 × 7 fuel.
polaris_dv1a.inp – simple PWR pin cell depletion calculation.
- BS96
S. M. Bowman and T. Suto. SCALE-4 Analysis of Pressurized Water Reactor Critical Configurations: Volume 5. 1996.
- God14
Andrew T. Godfrey. VERA core physics benchmark progression problem specifications. Consortium for Advanced Simulation of LWRs, 2014.
- JWE+14
Matthew Anderson Jessee, William A. Wieselquist, Thomas M. Evans, Steven P. Hamilton, Joshua J. Jarrell, Kang Seog Kim, Jordan P. Lefebvre, Robert A. Lefebvre, Ugur Mertyurek, and Adam B. Thompson. Polaris: a new two-dimensional lattice physics analysis capability for the SCALE code system. Technical Report, Oak Ridge National Lab.(ORNL), Oak Ridge, TN (United States), 2014.
- RE13
B. Roque and M. Erlund. International Comparison of a Depletion Calculation Benchmark on Fuel Cycle Issues, Results from Phase 1 on UOx Fuels. Technical Report, NEA/NSC/DOC, 2013.
- WK12
Mark L. Williams and Kang Seog Kim. The embedded self-shielding method. PHSYOR, 2012.