US microreactor apparatus begins tests

25 September 2023

Tests now under way using an electric-powered prototype of the US Department of Energy's (DOE) MARVEL microreactor will demonstrate the natural circulation that will be a critical part of the reactor's heat removal system.

The PCAT replica installed and ready for testing at Creative Energy's facility (Image: DOE Office of Nuclear Energy)

The primary coolant apparatus test - or PCAT - is a full-scale replica of the MARVEL microreactor. Built at Idaho National Laboratory (INL), the 12 foot (3.7 metre) tall machine was installed at Creative Engineers Inc's manufacturing facility in Pennsylvania in May, and loaded with sodium-potassium and lead-bismuth coolants to demonstrate heat removal from its electrically heated core. PCAT's Stirling engines were started for the first time on 19 September, Creative Engineers said.

CAT will provide data on temperatures and coolant flow to ensure the MARVEL reactor will perform as expected. The first phases of testing at PCAT will initially focus on demonstrating natural circulation, a critical heat removal mechanism within the system, DOE said.

The PCAT demonstration is an "important step in that process and will help validate and benchmark tools we use to accurately predict how the reactor will perform," Yasir Arafat, chief designer and project lead for MARVEL, said.

MARVEL - a liquid-metal cooled microreactor equipped with Stirling engines - is expected to produce 85 MW (thermal) using small amounts of high-assay, low-enriched uranium (HALEU) fuel. It is to be constructed at INL's Transient Reactor Test Facility - using off-the-shelf components, which will allow for faster construction - where it will be used to test microreactor applications, evaluate systems for remote monitoring, and develop autonomous control technologies. DOE has said it plans to connect the reactor to the lab's first nuclear microgrid.

The DOE said it is close to finalising the MARVEL design and is in discussion to procure key long-lead components for fabrication. The reactor could be operational as soon as the end of next year.

Researched and written by World Nuclear News