Power Distribution Control and Stochastic Observers for Flux Mapping for Advanced Heavy Water Reactor

India's three-stage nuclear power programme involves self sustaining Thorium closed fuel cycle based reactors. It has initiated design and development of the Advanced Heavy Water Reactor (AHWR). AHWR is a 920 MW (thermal) capac- ity, heavy water moderated, boiling light water cooled in natural circulation, vertical pressure tube type nuclear reactor. It is fueled by (Th-233U)O2 pins and (Th-Pu)O2 pins and the reactivity is mainly controlled by neutron absorber rods. Some advantages of Thorium-based fuel cycle are abundance of Thorium in In- dia, closed fuel cycle, reduction of radio toxicity of waste to a lower extent, proliferation resistance (prevent or discourage the production of weapon grade material). AHWR offers clean, sustainable nuclear energy, and is one of the ¿agship technologies of India's nuclear programme. The physical dimensions of AHWR are very large in comparison to neutron migration length, making it susceptible to Xenon induced oscillations and ¿ux- tilting. These undesirable oscillations are common with large nuclear reactors which, if not controlled, can pose unequal spatial distribution of power and increase the chances of fuel failure. Thus it is necessary to devise a control strategy to regulate these spatial oscillations.