A new βeff measurement system using the Californium Source Method

Abstract

SCK CEN, the national research center on nuclear energy located in Mol, has a zero-power reactor VENUS-F that supports the realization of the MYRRHA Accelerator Drive System. VENUS-F is used to verify calculation codes and nuclear data for MYRRHA. Research with VENUS-F provides an insight into the time-dependent behavior of a nuclear reactor by experimentally determining kinetic parameters.

This Master’s thesis focuses on the determination of the delayed neutron fraction βeff with the Californium Source Method. In addition, the neutron noise method (the Rossi-α method) is performed to determine the mean neutron generation time Λ. For this purpose, firstly an application system is devised to perform the βeff measurements using the Californium Source Method. Next, the experimental data are analyzed. Finally, Serpent2, which is based on Monte Carlo simulations, is used to determine correction factors that are necessary for the Californium Source Method. In addition to the measurement of the βeff and Λ values, their uncertainties are also determined.

The measurement system, consisting of the californium source attached to a remotely controlled moving mechanism, fission chamber with calibrated effective mass, neuron flux monitors and data acquisition system was successfully tested.