Presentazioni e Articoli Tecnici

Prototype Fast Breeder Reactor (PFBR) has two independent, diverse, fast acting & fail safe shut down systems to achieve the required level of safety & reliability (1). The shut down systems comprises of nine numbers of Control & Safety Rod Drive Mechanisms (CSRDM) & three numbers of Diverse Safety Rod Drive Mechanisms (DSRDM). DSRDM facilitates SCRAM of the reactor on abnormal condition by rapid insertion of Diverse Safety Rod (DSR) into the core. SCRAM is achieved by dropping both Control & Diverse Safety Rod’s. SCRAM is acronym for Safety Control Rod Accelerated Movement. An electromagnet located at the bottom end of DSRDM holds the DSR in the core during normal operation. The electromagnet is immersed in sodium and undergoes temperature variations (180ºC - 580 ºC) as seen by the liquid sodium which is a coolant in fast reactor. When the electromagnet is de-energized, the DSR falls under gravity leading to shutdown of the reactor. The electromagnet should be capable of lifting the DSR at all temperatures and should be able to drop the DSR within a specified time on demand. This requires calculation of the lifting capacity of the electromagnet at different currents and at various temperatures. In this work COMSOL has been used to calculate the lifting forces of the electromagnet at different currents and operating temperature (550ºC) and the predictions have been compared against the experimental data.