Inclusion of each type of device in the monitor is optional. This gives a plant the flexibility to select the precise environmental parameters to be monitored, according to plant-specific needs and budgetary constraints. The peak temperature monitors are intended mainly as screening devices. They can be used to quickly determine the highest environmental temperature reached in any location over a given time period such as a fuel cycle, or during an abnormal event such as a steam leak or HVAC malfunction. This will indicate whether the temperature was benign or potentially harmful to equipment.
More complete information is obtained by reading the integrating thermal monitors.
To evaluate component thermal degradation, it is necessary to know not only the peak exposure temperature, but also something about its variation over time. Following thermal annealing in the plant, the ITMs are again exposed to the fission source. At this point, the ITM contains both annealed and unannealed latent tracks. To read the ITM, these latent tracks are developed by chemical etching to a size that can be measured using an optical microscope. The Arrhenius equivalent temperature is also defined as that constant temperature over the time period of interest that produces the same effect as the actual varying temperature over the time period.