The effect of intermittent operation on local fission rate in the McMaster nuclear reactor

The McMaster Nuclear Reactor operates on a 16-hr/day/5-day/week schedule causing cyclic loading of Xenon in the core and requiring compensation by the control systems to maintain operations. The constant control rod interaction affects local fission rates. This paper confirms the relationship between Xenon load and control rod movement and studies the relationship between local fission rate and control rod insertion. The results provide information related to analysis approximations used in depletion calculations. In addition, comparisons are made between the current MNR operation cycle and a proposed continuous operational approach. The results are further discussed in the context of proposed Molybdenum-99 production at MNR.