Control cards

# : Comment

# A line started with a hash mark is considered a comment.

& : Line continuation

# An ampersand symbol at the end of the line &
is a line continuation symbol.

signal : User-defined signal

#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
# Signals
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     id        type      value
signal    TSTART    boolean   TIME      le        250
signal    TEMP      constant  600
signal    DCHAN     dens      CHAN
signal    RHO_CRDL  formula   K_CR*(TIN*1.73E-05 + TCRDL*1.70E-05-TVESS*1.70E-05 + TFUEL1*1.30E-05)
signal    RHO_CR    lookup    TIME      &
          0.0       0.0                 &
          0.0       250.0               &
          -50.0     252.0               &
          -50.0     3000.0
signal    LNTF1     function  ln        TFUEL1
signal    TCLAD     tclad     FR
signal    TCHAN     temp      CHAN
signal    TFUEL     tfuel     FR
signal    TIME      time

``id`` : user-defined signal id;
``type`` : signal type;
``value`` : signal value.

Currently available signal types (under development):

• boolean : any constant numeric value; the following logical expression can use signal ID, logical operator (lt, le, eq, ne, gt, ge), constant;

• constant : any constant numeric value;

• dens : average pipe density (kg/m³):

  • CHAN: pipe ID;

• formula : expression, including signal IDs, arythmetic operations (+, -, \*, /) and parenthesis.

• lookup: lookup table:

  • TIME: signal ID (x);

  • N pairs of numerical values x(i) and y(i) to approximate a function y = f(x). At every time step an output signal y is linearly interpolated for current value of the input signal x.

• tclad : fuel rod clad average temperature (K);

  • FR : fuel rod ID.

• temp : average pipe or heat structure temperature (K);

  • CHAN: pipe ID.

• tfuel : fuel rod fuel average temperature (K);

  • FR : fuel rod ID.

• time : time of the problem (s).

solve : Model activation flag

#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9----  ----0----
# Model activation flags</code
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     model
solve     fluid
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     model
solve     fuelrod
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     model
solve     pointkinetics
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     model               ng         meth
solve     eigenvalueproblem   25         DIF

• model : keyword of the model to be solved:

  • fluid : thermal-hydraulic model;

  • fuelrod : fuel rod behaviour model (fluid should be activated);

  • pointkinetics : point reactor kinetics model;

  • eigenvalueproblem : eigenvalue problem model;

    • ng : number of energy groups;

    • meth : method used by an eigenvalue solver:

      • DIF : neutron diffusion method;

      • MC : Monte Carlo method.

Note that even if the respective cards are present in the input file, the task will not be solved unless activated by the solve card.

t0 : Initial time

#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----</code>
# Initial time</code>
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----</code>
#####     tinit
t0        0.0

tinit : integration starting time (s).

tend : Integration time set

#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----</code>
# Integration time set</code>
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----</code>
#####     tend(s)
tend      100
tend      1000

tend : end of integration time interval (s).

The given example specifies two integration time intervals: 1) from t0 to 100 s and 2) from 100 s to 1000 s. The time steps inside the intervals are selected automatically by the ODE solver.

tol : Required solution tolerance

#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
# Required solution tolerance
#---- ----1---- ----2---- ----3---- ----4---- ----5---- ----6---- ----7---- ----8---- ----9---- ----0----
#####     rtol      atol
tol       1e-6      1e-4

rtol : relative tolerance; atol : absolute tolerance.