Efficient burn up of minor actinides is one of the most promising alternatives for minimizing waste in advanced nuclear fuel cycles. This work examines the concept of employing Z-pinch driven fusion source in a sub-critical transmutation reactor designed to burn up actinides and generate constant power. Its fuel cycle is designed to allow on-line fission product removal and fuel replenishment. The variation of the actinide inventory is an essential quantity used to calculate the energy multiplications and neutron spectrum, as well as to design an appropriate reactivity control mechanism.

In this paper we develop a method to calculate timedependent isotopic distributions, fuel feeding rate and fission product removal rate necessary to obtain a constant power level. The calculation is performed by using both MCise, a Monte Carlo isotopic inventory code, and MCNP5. An important feature of MCise for this system is the ability to simulate the on-line removal of fission products from the actinide mixture.

In addition to reporting the actinide inventory and burn rates, the impact of the actinide inventory on the fission/fusion energy multiplication will be examined.