# Kerma-based POWER renormalisation

In many scenarios the incident particle flux is not the primary known quantity, but some other normalisation which is equivalent to volumetric power density is known. This is common in power reactor simulations or other cases were heat extraction can be easily and accurately measured.

To accommodate these simulations a renormalisation of the flux can be performed by using the total kinetic energy release per mass (KERMA) microscopic nuclear data, together with an incident particle spectrum, to set the flux.

## POWER keyword usage

The POWER keyword initiates an overwrite of the flux normalisation based on a volumetric power and set of reactions whose KERMA values should be considered. The keyword takes the following arguments:

POWER power_level (W/cc) no_mat (positive integer) mt(i) i=1,no_mat

An example of the keyword for a 150 W/cc simulation using the total KERMA would be:

POWER 150 1 301


This will overwrite the flux and give an output stream for each instance, such as:

flux amplitude changed using POWER keyword: old value =  0.32500E+15
new value =  0.32513E+15 cm^(-2) s^(-1)