Safety assessment of two advanced ferritic steel molten salt blanket design concepts

In this article, we explore some of the safety issues associated with two advanced ferritic steel (AFS) molten salt blanket designs from the Advanced Power Extraction (APEX) design study [M.A. Abdou, The APEX Team, On the exploration of innovative concepts for fusion chamber technology, Fus. Eng. Des. 54 (2000) 181]. In particular, we examine radiological inventories, decay heat, waste disposal ratings, and toxic chemical inventories of these design concepts. In addition, we predict the thermal response of these blanket designs during accident conditions, and the mobilization of the radiological inventories and site boundary dose from the release of this mobilized material during a worst-case confinement-boundary-bypass accident. The molten salts being proposed for these blanket concepts are Flibe and Flinabe, and the structural material is a nano-composite strengthened ferritic steel alloy called 12YWT. The estimated dose at the site boundary is less than the no-evacuation limit of 10 mSv for a ground level release during conservative weather conditions if plant isolation occurs within 5 days.