Improvement and verification of inverse kinetics method

Inverse Kinetics Method is an effective online reactivity measurements method. The key issue of the Inverse Kinetics Method is how to calculate the derivative and integral of the neutron signal accurately. The derivative of the neutron signal is very sensitive to random noise which can not be avoided in measurement. Several methods which can restrain noise are presented and numerically simulated, including digital filter and cubic smoothing splines. As shown from the numerical simulation, cubic smoothing splines can restrain the noise in the neutron signal, even for the signal noise ratio of 5%, without the delay effect normally existed in digital filter. Therefore, treatment of the noise in the neutron signal is the key issue for the inverse kinetics method, and cubic smoothing splines is a good choice. (authors)