Molten salt reactors (MSRs) are a class of nuclear reactor which uses a molten ionic liquidas either the coolant or also as the fuel. While a 8 MWth MSR was successfully operatedin the 1960s it was not until the early 2000s that MSRs gained widespread attention. Sincethen MSRs have enjoyed plentiful research support. Despite such support only one generalMSR fuel cycle analysis tool is available for use by the research community and even thisthis tool lacks features necessary for modelling a MSR, and so possibly providing answers ofa lower quality.In this work a method is proposed and implemented within the SERPENT 2 reactorphysics Monte-Carlo code. This method, named ADER - the Advanced Depletion Extensionfor Reprocessing - is a seamlessly incorporated source code modification to the SERPENT2 base code which allows the user to define arbitrary collections of elements, isotopes, andchemicals as well as relationships among them.Furthermore ADER allows the user to specify a variety of mass flows subject to theconstraints as defined through the collections of elements, isotopes, and chemicals the userhas structured. Along with support for constraints involving both corrosion and nuclearcontrol concerns, ADER allows the user to optimize the solution against a quantity of interest- e.g, total uranium fed into the system.Through these structures much of the complex chemistry, corrosion modelling, and nuclear concerns of operating a MSR can be linearized and solved against an optimizationtarget, which is necessary given the large number of constraints and variables in such aproblem space. Linearization reduces the problem complexity and eliminates concerns overlocal versus global optimization targets. Within the typically narrow operating parametersof MSRs linearization is an appropriate approximation to the higher dimensional equationsrepresenting the phenomenon involved.2This linear system and optimization target may then be passed to a linear optimizationsolver, in this work the CLP library as part of the COIN-OR package, from which an optimized system material composition and material flows solution may be found. ADER thenuses this solution to create a brand new depletion matrix which SERPENT 2 then solvesusing the CRAM approximation method.From this algorithm a more accurate modelling of MSR fuel cycles and physics maybe arrived at through the consideration of chemistry driven limitations, corrosion drivenlimitations, nuclear driven limitations, and operator driven limitations. Results from thisimplemented method indicate that ADER drives the MSR fuel cycle simulations towardsa more physically representative result. Unfortunately, as detailed later in this work, anunderlying and pernicious numerical instability issue was uncovered within the linear optimization library selected for this work. Any future work on this method must begin with theadoption of a quadruple-precision floating-point linear optimization library over the currentimplementation of CLP as used in ADER.In the following chapters an introduction to MSRs and their fuel cycle modelling isgiven. Following this the theory behind ADER and its implementation within SERPENT 2is discussed after which the results from one of the less numerically unstable simulations ispresented after which concluding remarks are given
