Multi-module approach to modularity in a neutronically coupled high temperature multi-modular system

A variety of small modular reactor designs exist, each sharing a similar characteristic: modularity. Different approaches to modularity exist, and the multi-module approach is presented here in the design of the High Temperature Integrated Multi-Modular Thermal Reactor. The core consists of several self-contained modules each of which are subcritical and when several modules are brought into proximity of one another, a single critical core is formed. The modular geometry allows for several unique operating conditions which are considered here. The extension of the core lifetime by battery type module shuffling and refueling is shown. The neutronic performance of the core relative to a single reflected module and a very large module is investigated and the use of modules is found to be a good choice. Room temperature sub-criticality is verified, shipping accidents are investigated, and the neutronic aspects of a loss of coolant accident are analyzed. Control elements are discussed, implemented, and analyzed.