# Keyword:POWER

POWER power_level no_mt
mt(i) i=1,no_mt

POWER causes the flux to be adjusted to give the power level (Watts per cc) given by the first argument, where the power is computed from the sum of the no_mt kerma powers given by the collapsed kerma cross-sections with mt values mt(1), mt(2), ...mt(no_mt). All of the available kerma mt values are specified in the mt tables.

The POWER keyword is an alternative method for setting the incident particle flux to the FLUX keyword. If the kerma data are not available, for the mt values given, then a fatal error will be issued. If the mt are outside the range for kerma, a fatal error will be issued. At present kerma data are available for the TENDL data. POWER causes a line of the form shown below to be written to the output stream every time it is called:

flux amplitude changed using POWER keyword: old value = 0.32500E+15
new value = 0.32513E+15 cmˆ{-2} sˆ{-1}


Example usage to set the power to 130 W/cc using the total kerma:

< -- Control phase -- >
...
FISPACT
* Title of the simulation
< -- Initial phase -- >
...
POWER 1.3E+2 1 301
...
< -- Inventory phase -- >
...


The power level is set based on the inventory at the start of the integration interval over which the flux amplitude is fixed. In general, the power will evolve, and so it may be necessary to break a long irradiation phase into sub-steps and reset the flux at each sub-step. This may be achieved using STEP and the PULSE/ ENDPULSE loop structure. For example, a one year irradiation may have four silent intervals followed by a last one that produces inventory output:

...
PULSE 4
POWER 100.0 1 301
TIME 0.2 YEARS STEP
ENDPULSE
POWER 100.0 1 301
TIME 0.2 YEARS ATOMS
...