Thermal methods for on-line power monitoring of the IPR-R1 TRIGA Reactor

The IPR-R1 Research Reactor is a TRIGA Mark I type reactor. It is a pool reactor, and the fuel elements are cooled by water natural convection. The heat removal capacity of this process is great enough for safety reasons at the current maximum 250 kW reactor power level. However, a heat removal system is provided for removing heat from the reactor pool water. Power monitoring of nuclear reactors is always done by means of neutronic instruments. In the IPR-R1 the power is measured by four nuclear channels. This work presents the results and methodology for monitoring the power of this reactor by three thermal processes. One method uses the temperature difference between an instrumented fuel element and the pool water below the reactor core. The other two methods consist in the steady-state energy balance of the primary and secondary reactor cooling loops.