Experimental determination of the zero power transfer function of the AKR-2

The transfer function is a basic characteristic of every nuclear reactor. It describes how a perturbation at a given place and time influences the neutron flux. In case of a known perturbation, the determination of characteristic reactor parameters is possible. The present paper shows an experimental method to determine the gain of the zero-power reactor transfer function (ZPTF) of the AKR-2 reactor at TU Dresden and the comparison to the theoretical shape of the ZPTF derived from kinetic parameters simulated with MCNP. For the experiments, a high-precision linear motor axis is used to insert an oscillating perturbation acting at frequencies smaller than the lower bound of the plateau region of the ZPTF. For higher frequencies, a rotating absorber is used. This device emulates an absorber of variable strength. The reactor response is detected with a He-3 counter.
The data evaluation shows good agreement between measured and corresponding theoretical values of the gain of the ZPTF.