The Functional Mock-up Interface as a unified framework to enable multi-scale, multi-fidelity and control-oriented simulations of nuclear reactors

The paper proposes a general methodology to address the problem of coupling high-fidelity tools for the simulation of nuclear reactors with lower fidelity system tools that can be used for instance to simulate the balance of plant and/or the reactor control and protection systems. Based on efforts carried out by the engineering community at large, we propose to make use of the Functional Mock-up Interface, an industry standard that has been professionally developed for more than a decade with the objective of enabling seamless coupling of heterogeneous simulation systems. The coupling is obtained by encapsulating simulation tools into independent objects called Functional Mock-up Units (FMUs) that can communicate among them at runtime and in-memory via a standardized interface. In this preliminary work, we test this methodology by using OpenFOAM and the Modelica language as examples of high- and low-fidelity tools, respectively. We build on previous work from the aerospace community to couple OpenFOAM and FMUs, and we extend it to allow for the simulation of nuclear reactors using the OpenFOAM-based GeN-Foam multi-physics code.