US-based X-Energy Reactor has joined forces with Kinectrics – engineering, testing and certification services company – to design, construct and operate a commercial-scale helium test facility (HTF).

The facility is intended to test and verify the performance of critical structures, systems and components of X-Energy’s Xe-100 advanced small modular reactor (SMR) in helium-based high-temperature and high-pressure environments.

The Xe-100 design aims to circulate helium gas to transfer heat from the reactor core through a heat exchanger to generate high-temperature steam that can be used to generate electricity to supply heat for industrial processes. The facility is also expected to bring together nuclear operators, researchers, and engineers to drive additional potential optimisations of the reactors.

X-energy is receiving support from the US Department of Energy, under the Advanced Reactor Demonstration Program, to deliver a four-module version Xe-100 demonstration plant and a commercial TRISO fuel fabrication facility. The company has recently agreed to work with materials science company Dow to develop a four-unit Xe-100 facility at one of Dow's US Gulf Coast sites. This will be supported by testing and design validation at the HTF, X-energy said. Energy Northwest has also named the Xe-100 as its preferred technology for the prospective deployment of an SMR in Washington state by the end of the decade.

The companies expect to announce the HTF site later this year and to complete its detailed design by the end of 2023, targeting an operational facility in 2025. Data collected from testing in the HTF will be used to refine Xe-100 start-up and commissioning procedures and to gain critical operating experience to inform future reactor maintenance, operations, and staff training. X-energy CEO Clay Sell said the HTF “is an integral part of testing our systems and components in expected operating conditions and verifying their safety, operability, and reliability”.

The Xe-100 is a high-temperature gas reactor with a thermal output of 200 MWt or an electrical output of 80 MWe. It is one of two designs selected by the US Department of Energy (DOE) in 2020 to receive $80m each of initial cost-shared funding to build an advanced reactor demonstration plant that can be operational within seven years. The Xe-100 evolved from both the UK’s Dragon reactor at Winfrith in Dorset and the Pebble Bed Modular Reactor project in South Africa.

It will use TRIstructural ISOtropic (TRISO) fuel comprising three layers of carbon and ceramic materials that surround kernels or balls of high-assay low-enriched uranium (HALEU) fuel.

X-energy, which expects its first reactor to be operational in 2028, recently announced plans to install its first Xe-100 at one of Dow’s US Gulf Coast sites. The first commercial deployment of the Xe-100 had previously been expected to be a four-unit plant near Energy Northwest's Columbia NPP in Washington. Energy Northwest remains committed to deploying an advanced SMR in Washington state by the end of the decade, and that the Xe-100 is its preferred technology. X-energy UK Holdings and Cavendish Nuclear also propose SMRs in the UK.

The Xe-100 will use circulating helium gas to transfer heat from the reactor core through a heat exchanger to generate high-temperature steam that can be used to generate electricity or supply heat for industrial processes. The HTF will test Xe-100 components and instruments under operating conditions and without the presence of any nuclear materials. These tests will enable design verification and give Kinectrics and X-energy performance data on key reactor systems, X-energy said.

Before it was closed down, South Africa’s PebbleBed Modular Reactor programme included a HTF which was under construction next to the SAFARI-1 reactor It included a helium purification facility and heat exchangerand fuel handling system. Construction started in 2004 and its 40 metre high tower was a dominant feature of Pelindaba.

Kinectrics CEO David Harris said the testing provided by the planned HTF will support "timely commercialisation" of the Xe-100. "This project is part of a long-term partnership between X-energy and Kinectrics. We expect the Xe-100 will produce electricity and high temperature process steam in a safe and reliable manner, which enables our clean energy future," he said.

X-energy and Kinectrics expect to announce the HTF site this summer and complete its detailed design in 2023, with the goal of having an operational facility in 2025. Working alongside a Kinectrics team, X-energy engineers expect to refine Xe-100 start-up and commissioning procedures using data collected from HTF testing and to gain critical operating experience to inform future reactor maintenance, operations, and staff training.

Image: The PBMR Helium Test Facility Pelindaba in South Africa