Mathematical and Computational Modelling for Nuclear Criticality Safety Analysis and Assessment of Interacting Arrays of Loosely Coupled Systems

其目的是开发新的数学和计算方法，用于模拟含有裂变材料的松散耦合系统的相互作用阵列的核临界度偏移行为，其中一些阵列组件是次临界的，一些是超临界的，或者在系统中引入外来（或外部）中子源。就燃料循环的前端和后端而言，核材料的物理形态和物质相的范围很广，从金属系统到粉末、饼状物、浆状物、污泥、乳液、胶体和悬浮液。这种材料通常储存在储存设施和建筑物内的各种各样的具有不同几何形状的不同容器中，通常作为这种储存容器的阵列。含有裂变材料的相互作用阵列可大致分为明确界定的阵列和不明确界定的阵列。在明确定义的相互作用阵列中，裂变单元或体的组成、密度、大小、形状和位置是“先验的”，被充分表征或已知。此外，反射和调节材料的分布和组成被相当精确地定义。总的来说，这个博士项目将为国防部承包商提供一套独特的方法，可以用来模拟目前可能的更广泛的场景。大多数特殊核材料以各种各样的形式储存在设施中，通常以规则间隔排列。这些方法也将对核燃料循环的其他部分感兴趣。

The aim is to develop novel mathematical and computational methods for modelling the nuclear criticality excursion behaviour of interacting arrays of loosely coupled systems containing fissile material where some of the array components are sub-critical and some are super-critical or where an extraneous (or external) neutron source is introduced into the system. In terms of the front and back end of the fuel cycle nuclear material is found in a very wide range of different physical forms and material phases from metallic systems, to powders, to cakes, to slurries, to sludges, to emulsions, to colloids and also suspensions. This material is often stored in a wide range of different containers with different geometries within storage facilities and buildings often as arrays of such storage containers. Interacting arrays containing fissile material can broadly be categorised as well defined arrays or ill-defined arrays. In well-defined interacting arrays the composition, density, size, shape and position of the fissile units or bodies is "a priori" well characterised or known. In addition the distribution and composition of reflecting and moderating materials is defined fairly precisely.Overall this PhD project would provide the MoD contractor with a unique set of methods that can be used to model a wider range of scenarios that currently possible. Most special nuclear material (SNM) is stored in facilities in a wide variety of forms and usually in regularly spaced arrays. The methods will also be of interest to other parts of the nuclear fuel cycle as well.