Constructive development and design justification of the protective shell of a nuclear reactor made of reinforced concrete

Introduction. This paper provides materials justifying the introduction of a new constructive solution for the reinforced concrete protective shell of a nuclear reactor in a prefabricated and monolithic design.

Aim. Among the tasks that were set during the development of the constructive solution, the main one was to ensure the work of reinforced concrete for compression under all types of loading and the perception of tensile forces by ropes that are in a free state, available for maintenance and operation.

Materials and methods. The calculations were performed by the finite element method using a software package MicroFe-StaDiCon for calculation of the spatial structures for strength, stability and vibrations.

Results. A fundamentally new constructive solution has been developed for the protective shell of the nuclear reactor of the NPP, consisting of reinforced concrete elements in the form of cylindrical folds with a bulge directed towards possible external and internal force emergency effects, including the explosion of the reactor. Variants of protective shells have been developed with the elaboration of fundamental technical solutions for unified folded elements made of reinforced concrete with the possibility of their monolithic and prefabricated manufacture. A scheme of open arrangement and tensioning of cable bundles with tension transfer to pre-fabricated structures of the inner and outer parts of the protective shell is proposed.

Conclusions. This design solution provides compressive forces in reinforced concrete of the folds of the inner and outer parts of the protective shell from the load during loading, which prevents the formation of cracks in them. The tensile forces in the shell are perceived by the prestressed reinforcement located inside its structure, free for maintenance and control. In the process of work, fundamental solutions have been developed for the structural nodal joints of prefabricated folded reinforced concrete elements, technological holes in the shell structure and the implementation of prestressing in it. A comparative technical and economic analysis of the proposed and existing inner protective shell showed the possibility of reducing concrete consumption by 1.5–2 times, non-stressed reinforcement by 3–4 times, construction time by 4 times.

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