Date of Award

2010

Document Type

Campus Access Thesis

Department

Nuclear Engineering

First Advisor

Travis W. Knight

Abstract

The challenge of estimating the radiation dose received by a worker is a complex task. This study was done to examine radiological hazards introduced to workers from the fabrication of fuels with minor actinides (MA) and reprocessed uranium (RepU). Of particular concern is the increase in gamma source term from the daughter products in RepU and the mixed neutron and gamma fields introduced by MA recycle. In the interest of keeping the glovebox worker's radiation dose as low as reasonable achievable (ALARA), dose rates were calculated for various fuel compositions for light water reactors (LWR) and fast reactor (FR) mixed oxide (MOX) fuels with and without MA. The impact of varying the separation efficiency of americium (Am) and curium (Cm) was examined because separation steps in reprocessing and recycling do not allow for the complete separation of Am from Cm. The additional Cm will cause a sufficient increase in the neutron source term. The sensitivity of the fuels to aging was also examined by decaying the oxides from 6 months to 3 years to simulate the effect of delays in reuse of recycled materials. The highest gamma and neutron sources were used to calculate the additional shielding requirements that would be needed for fuel fabrication. Through information gained from this study, it can be concluded that a standard glovebox with one quarter inch stainless steel walls can be used to fabricate fuels with Am with little to no additional shielding. The introduction of small amounts of Cm in the fuels will require the fuel fabrication to be preformed remotely in hot cells. Thus, stressing the importance of developing methods to increase the separation efficiency of Am from Cm.

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