The UK Department of Business, Energy and Industrial Strategy (BEIS) has recently launched a national R&D programme with a work package on Digital Reactor Design. It consists of development of a Nuclear Virtual Engineering Capability within an integrated Modelling and Simulation Programme. A key challenge of nuclear reactor modelling and simulation is system complexity, which arises from a wide range of important multi-physics phenomena appearing across multiple length scales requiring a multi scale and multi methodological approach. In a final stage an integrated nuclear digital environment (INDE) is envisaged providing a link between modelling and simulation data and real world data across the whole nuclear lifecycle. For the demonstration of the capabilities 'Challenge problems/Use cases' will be defined to target future capability developments on the path to the future integrated nuclear digital environment (INDE). PWR and AGR simulation cases have already been specified. The AGR case considers the through-life structural performance of graphite bricks in a stepwise multi-scale, multi-physics approach to support reactor operations and lifetime extension. The PWR case is based on core multi-physics modelling of a control rod ejection accident. Additional use cases to demonstrate the advanced visualization tools of the virtual engineering centre are currently under development.