A draft architecture for a level 3 PSA code

An initial sketch of a software architecture for code conducting consequence assessment of severe nuclear accidents (level 3 probabilistic risk analysis) is presented. The code, if implemented, would complement FinPSA Level 1 and FinPSA Level 2 codes being developed by VTT. The purpose of the sketch is to facilitate communication with stakeholders (NPP companies, regulatory agencies, developers), and form a basis to further architectural specification and software development if a decision is made to develop the software. Existing applicable software is reviewed, with emphasis on free and open source software. Good alternatives for conducting atmospheric dispersion computations, geographic information management, and statistical and mathematical analyses exist. Also some code directly applicable to level 3 purposes is available. The functional and information viewpoints of the architecture are presented. In the functional viewpoint, the main components, their interfaces, and dependences between them are outlined. The code shall include components for atmospheric and aquatic dispersion estimation, health consequences assessment, and economic consequences assessment, among others. In the information viewpoint, the most important (in terms of data to be handled) information is presented. Existing functional requirements are mapped to components taking care of their implementation.