Input File Guide¶
The structure of the input files is broken up into blocks with character sequences seperating the blocks The first line in the file is a comment, this should be something meaningful to distinguish the problem from others
Parameter Block¶
Begins with read parm and ends with end parm
| Parameter | Value | Description |
|---|---|---|
| DebuggIt | yes or no | Turn on DEBUG printing - prints a lot of stuff |
| ReadDif3 | yes or no | Read DIF3D external file for power profile and such |
| NlIters | Integer | Set number of maximum nonlinear iterations |
| Material | Integer | Number of fissional materials |
| NumDelay | Integer | Number of delayed neutron groups |
| TotalPow | Real | Total axial power [\(n/s-cm\)] |
Time Block¶
Begins with read time and ends with end time
| Parameter | Value | Description |
|---|---|---|
| TDMethod | integer | 0 - forward Euler 1 - backward Euler |
| TimeSolv | yes or no | Perform a time dependent calculation |
| TimeStep | Double | Indicate fixed time step size, ex: 1E-5 |
| EndTime | Real | Indicate the total length of the simulation |
| StrtTime | Double | Beginning point of the calculation |
| SaveTime | Real | Interval to write out spatial solution files to |
Perturbation Block¶
Begins with read perturbation and ends with end perturbation
| Parameter | Value | Description |
|---|---|---|
| Feedback | Integer | 0 - (default) no feedback 1 - temperature 2 - instant beta |
| StepPert | yes or no | Perform a step perturbation or not |
| StrtStep | Double | Start time for step perturbation |
| EndStep | Double | End time for step perturbation |
| RampPer | yes or no | Perform a ramp perturbation or not |
| StrtRamp | Double | Start time for ramp perturbation |
| EndRamp | Double | End time for ramp perturbation |
| ZaggPert | yes or no | Perform a zig-zag perturbation or not |
| Reactiv | Real | Reactivity insertion for step and ramp |
| TimeCons | Real | Time constant for mass flow rate reduction |
| PerFlow | Real | Percent reduction in flow rate over 1/TimeCons |
| MassFlow | Real | Mass flow rate [\(g/cm^3\)] |
| GenTime | Real | Neutron generation time [\(s^-2\)] |
Mesh Block¶
Begins with read mesh and ends with end mesh
| Parameter | Value | Description |
|---|---|---|
| ElemSize | Integer | Size of elements |
| NumElems | Integer | Number of equal spaced elements in the model |
| NumNodes | Integer | Number of nodes per element |
| FuelInlt | Integer | Starting element of the inlet plenum |
| CoreStrt | Integer | Starting element of the main core region |
| CoreEnd | Integer | Final element of the main core region |
| FuelOutl | Integer | Final element of the outlet plenum |
| StartHex | Integer | Heat exchanger starting element location |
| EndHexch | Integer | Heat exchanger ending element location |
| CoreArea | Real | Area of the fuel core [\(cm^2\)] |
| PipArea | Real | Area of the piping [\(cm^2\)] |
| HexcArea | Real | Area of the heat exchanger [\(cm^2\)] |
Delay Block¶
Begins with read delay and ends with end delay
| Parameter | Value | Description |
|---|---|---|
| mat | Integer | Material identifier, not be greater than nmat |
| alam | Real(ndg) | Decay constant for each delayed group |
| beta | Real(ndg) | Delayed neutron fraction for each delayed group |
Sample Input File¶
Heat Exchanger Overcooling Model of Chrloride type problem
read parm
DebuggIt=no
ReadDif3=no
NumDelay=6
Material=1
NlIters=50
TotalPow=10
end parm
read time
TimeSolv=yes
TDMethod=1
TimeStep=1E-3
EndTime=20.0
StrtTime=0.0
SaveTime=10.0
end time
read pert
Feedback=0
StepPert=yes
RampPert=no
ZaggPert=no
StrtStep=0.0
EndStep=1.0
StrtRamp=0.0
EndRamp=0.0
Reactiv=0.003
TimeCons=0.0
PerFlow=0.0
MassFlow=0.0
GenTime=2.0E-5
end pert
read mesh
ElemSize=1.0
NumElems=10
NumNodes=3
FuelInlt=1
CoreStrt=2
CoreEnd=9
FuelOutl=10
StartHex=1
EndHExch=1
CoreArea=7.49E4
PipeArea=7.49E4
HexcArea=100000
end mesh
read delay
mat=1
alam=0.0127 0.0317 0.115 0.311 1.4 3.87 end
beta=2.66E-4 1.491E-3 1.316E-3 2.849E-3 8.96E-4 1.82E-4 end
end delay
Input file structure to read in from DIF3D¶
Values from DIF3D can be read in and projected onto the domain in the 1D problem Right now it reads in the power, power fraction, doppler reactivity worth, and density reactivity worth. These are all spatially dependent. These values are integrated across the AREA specificed in the DIF3D problem. It will read in the values and project them up to that axial height. For example:
Volume Area Z-Coord Power Frac Power Doppler Expansion 200 20 10 0.00E+00 0.0+00 0 0 200 20 20 1.85E+06 6.1-03 -3.31E-07 -1.02E-06 200 20 30 3.08E+06 1.0-02 -1.01E-06 -5.11E-07
This would project from locations 10 - 20 a power of 1.85E+06/(20-10). Similalrly, from 20 - 30 a power of 3.08E+06/(30-20)
The file read in is assumed to be titled: dif3d_values.txt It assumes the file is read in as follows:
| Line | Value | Units |
|---|---|---|
| 1 | Total number of axially integrated values | [integer value] |
| 2 | Spatially integrated power to be read in | [Watts] |
| 3 | Spatially integrated fraction of power | [Normalized by total] |
| 4 | Spatially integrated doppler worth | [reactivity] |
| 5 | Total change in temperature for the perturbation | [K] |
| 6 | Spatially integrated density worth | [reactivity] |
| 7 | Total change in density during perturbation | [in percent] |
| 8 | Column wise values begin here. | |
| C 1 | Axial z value from DIF3D | [cm] |
| C 2 | Volume | [\(cm^3\)] |
| C 3 | Cross sectional area | [\(cm^2\)] |
| C 4 | Power for that AREA | [\(Watt/cm^2\)] |
| C 5 | Fractional power for that AREA | [normalized by total] |
| C 6 | Doppler reactivity worth | [reactivity/\(cm^2\)] |
| C 7 | Density reactivity worth | [reactivity/\(cm^2\)] |