The possibilities of using hybrid computer systems for computing digital twins using accelerator computers with massive multi-core parallelism are investigated. The structurally scalable architectures of such accelerators open ways for the integration on system-level of mass multi-core parallelism into the virtual environment of cloud systems. The proposed architecture multiSIMD of such accelerators is founded on the scalable multiprocessor the architecture of the accelerator computer PS-2000, which was produced in a large industrial series in the absence of world analogues. The high efficiency of this architecture was confirmed by the wide practice of application in various spheres of the national economy. The use of the proposed accelerator computers for in-chip integration of mass multi-core parallelism into the virtual environment of cloud servers will make it possible at the advanced conceptual level of cloud systems to expand on orders of magnitude the range of scaling the computing performance of cloud servers when building digital twins for critically important classes of technogenic system., including for nuclear power plants (NPP) with increased requirements for safety and computing performance.