The NEA is launching a new international Heat‑Pipe Microreactor (HP‑MR) Benchmark, a three‑year initiative designed to advance multiphysics modelling for next‑generation microreactor systems.
Heat‑pipe microreactors are gaining attention as resilient energy sources capable of potentially supplying power to remote sites, emergency zones and future space missions. Their compact design relies on passive heat pipes (sealed, two‑phase devices that move heat without pumps or moving parts), offering exceptional reliability and simplicity. As interest in these systems increases, so does the need for co-ordinated international efforts to compare modelling approaches and strengthen simulation tools.
The new benchmark, conducted under the Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS) of the Nuclear Science Committee, intends to bring together experts from research institutes, universities and industry. The benchmark is organised into three phases, covering the characterisation of the microreactor neutronics and thermal-hydraulics, the simulation of steady-state multiphysics and the study of transient scenarios, such as load-following operations and heat pipe failure events. The benchmark specification is derived from the 2 MWth heat‑pipe microreactor model developed at Argonne National Laboratory.
Workshops and technical exchanges will be held throughout the benchmark study to facilitate collaboration and develop best practices for analysing these innovative reactor systems. The final benchmark report, expected in 2029, will provide a shared foundation for future reactor design, licensing and educational activities.
Institutions interested in contributing to the HP‑MR Benchmark study may contact the WPRS Secretariat for further information: wprs@oecd-nea.org.
