Physics aspects of adjuster rod in Dhruva

Cobalt based Adjuster Rod has been installed at G-19 lattice position, an important 150 KW unoccupied loop position, of Dhruva reactor. It was necessary to considerably reduce the minimum four days period generally required to bring the reactor at rated power from xenon free shut down state. It has, in turn, led to the enhancement of capacity factor, better utilization of fuel and improving the thermal safety margins due to increase in equilibrium moderator level. The design of adjuster rod has been optimized for the production of much needed high specific activity ⁶⁰Co isotope for Teletherapy and many industrial applications. Introduction of adjuster rod was also important for enhancing the thermal neutron flux level by a factor of five at self serve facility required for short and medium duration exposures of Research and Development material studies. This article summarizes various physics aspects of recently commissioned adjuster rod assembly in Dhruva reactor core. (author)