Pre-conceptual design of prestressed concrete containment for a GFR nuclear reactor

The paper presents the process of a pre-conceptual design, analysis and optimization of a prestressed concrete containment vessel (PCCV) for a new type of gas-cooled fast reactor (GFR). The feasibility of the PCCV concept has been confirmed by a preliminary study presented in a previous paper. This paper builds on the prior results and presents an advanced analysis of the PCCV conducted using a global 3D non-linear coupled thermomechanical finite element model. The model is presented together with the results, revealing problems regarding unacceptable cracks or excessive compressive stresses in atypical areas of the structure (the gusset, the peripheral part of the dome, the ring beam, and the equipment hatch area). In the main part of the paper, various approaches to the modification of these regions are explored (e.g. modifications of geometry, prestress or steel reinforcement of the structure). The considerations that lead to the selection of the most beneficial modifications are explained in detail. The final version of the pre-conceptual design meets all of the defined criteria for the behaviour of the PCCV in the operation stage and during loss of coolant accident (LOCA). The main contributions of the paper are that it: (a) presents the process of modelling, analysis, and optimisation of a PCCV, (b) explores possible approaches to the modification of the atypical parts of a PCCV, (c) provides solutions for various design problems, and (d) presents and verifies a suitable design of a PCCV for a new type of GFR.