Estimation of precursor concentration in a research reactor by using second order sliding mode observer

The paper pertains to novel higher order sliding mode observer (SMO) design for estimating precursor concentration of a nuclear research reactor. The linear and nonlinear models of Pakistan Research Reactor-1 (PARR-1) have been tuned and validated with experimental data. These models are subsequently used for higher order sliding mode observer design and performance evaluation. In thermal reactors, precursor concentration is a very important reactor variable because it is responsible for delayed neutron production and finally for reactor control. Linear observers have been used in the past to estimate precursor concentration, but the bandwidth is much limited and performance degraded as the operating point is changed. The nonlinear observer can cater for this problem in a much efficient manner. In this paper a robust nonlinear observer for estimating precursor concentration has been developed by using second order sliding mode technique. The higher order sliding mode observer is efficient and has the main advantage of reduced chattering. The observer estimates the precursor concentration with the measurement of neutron flux only and the estimated value is in close agreement with the theoretically calculated value.