The U.S. Department of Energy (DoE) announced on April 23^rd that the Argonne National Laboratory (ANL) has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop). The upgrade is the first of its kind in the U.S. in more than thirty years, according to the DoE. The exchange will help test components and operations for the sodium-cooled fast reactors currently being developed.

Sodium-cooled fast reactors use liquid sodium as a coolant instead of water. They operate at higher temperatures and lower pressures than current commercial nuclear reactors. They achieve high power density with low coolant volume and sustain the fission chain reaction with fast neutrons. They are currently used in several countries including the US, Russia, China, and India.

More than seven hundred and fifty gallons of reactor-grade sodium flow through METL, making it the “nation’s largest liquid metal test facility,” according to the DoE. METL may not hold that record for long, however. TerraPower is a sodium fast reactor developer with cost-shared funding under the Advanced Reactor Demonstration Program to build a grid-scale Natrium reactor. It is currently constructing a sodium test and fill facility in Kemmerer, Wyoming, which is constructed to hold four hundred thousand gallons of liquid sodium.

A cold trap like the one that was just replaced in METL is a critical component of liquid metal reactor designs. It is utilized to filter out oxide impurities present in the sodium coolant. If these impurities are not removed, they can cause accelerated corrosion of the systems and lower flow rates, degrading the reactor’s performance.

ANL replaced the component to meet specifications for future METL experiments. The facility uses welded construction techniques that the DoE says are “consistent with the maintenance of any advanced liquid metal reactor.” The replacement project builds U.S. experience in working with and replacing sodium loop components.

The sodium in the cold trap was frozen before the cold trap was removed from the system and a new one was welded onto the sodium piping in its place. After months of planning, the process was accomplished in two weeks. During the replacement process, the rest of the sodium in the test loop remained molten and in operation, according to the DoE.

Matthew Weathered is a principal nuclear engineer at ANL. “It’s exciting. The METL team is revitalizing and developing these key operations and maintenance techniques to ensure we are able to deploy U.S. sodium cooled reactors in the near future.”

METL was developed in 2018 to help advance research on liquid metal technologies and to test components for potential use in sodium fast reactors. The facility can reach an operating temperature of six hundred and fifty degree Fahrenheit. This is within the typical sodium reactor temperature range.

Reactor developers who are working with Argonne’s team at METL include ARC Clean Energy, Oklo, and TerraPower. METL plans to expand its testing capabilities in 2026 with the installation fifth test vessel.

The cold trap replacement project was funded through the DoE’s National Reactor Innovation Center (NRIC), which funds operations and maintenance activities at the METL facility. ANL consulted with the French Alternative Energies and Atomic Energy Commission before performing the replacement operation.

Argonne National Laboratory

Great British Nuclear (GBN), the arms-length body set up to oversee the U.K.’s plans for new sources of nuclear power, is getting ready to launch a tender to procure up to two owner’s engineers as part of its small modular reactor program.

GBN said in its recent announcement, “The Owner’s Engineer (OE) will provide essential independent assurance to the Intelligent Customer and Intelligent Client for the relevant SMR project. This will support the deployment of first-of-a-kind nuclear technology in the U.K. and facilitate GBN’s goal of reaching a Final Investment Decision(s) for up to two SMR projects. In particular, the OE will act as a ‘client friend’ to the Intelligent Customer and Intelligent Client and provide competent resources to undertake specification, oversight, audit, review and advice for decisions relating to design, scope, budget, risk, delivery and contract compliance. It will also play the role of subject matter expert to deliver independent technical and delivery Line of Defence 2 assurance on major design and build contracts.”

GBN said that the total value of the contract is eight hundred million dollars, assuming that two contracts are awarded (one for each planned SMR project), each with a total contract value of up to four hundred million dollars. However, GBN notes that the actual value will depend on a number of different factors. The actual duration of the contract(s) is envisaged to be about fourteen years, but GBN said it will set a completion date once it has selected the SMR technology partner(s).

GBN explained, “It is expected that SMEs (small and medium-sized enterprises) will have the chance to participate in this procurement through a tenderer’s supply chain, a joint venture, a special purpose vehicle or a consortium.”

The tender notice is expected to be published on the 2^nd of June of this year, with submissions accepted until the 19^th of September. A decision on the contract winner(s) is expected to be made on the 12^th of March 2026.

GBN said that there will be two phases in the OE procurement process. In the first phase, tenderers will need to respond to the Procurement Specific Questionnaire (PSQ). This document will include the required conditions of participation. If the response submitted by a particular tenderer satisfies all the relevant conditions, the tenderer will be invited to submit a tender as part of the second phase of the procurement. GBN said it will then review the tenderer’s proposals against questions covering technical, commercial and social value criteria.

GE Hitachi, Holtec, Rolls-Royce SMR and Westinghouse are the shortlisted technology provides being considered. Three of them have confirmed that they have submitted their final tender response to GBN. The fourth provider – Westinghouse – has yet to confirm whether it has submitted its final tender. Following the confirmations of submissions, GBN made the announcement of the OE.

In February of this year, GBN said that it remains on track to select the chosen technology before summer of 2025. A final investment decision to select the winner is expected to be made in 2029.

Great British Nuclear