2020 ANS Virtual Winter Meeting: Advanced nuclear reactors and power systems

“Advanced Nuclear Reactors and Power Systems-I” on November 18 during the 2020 ANS Virtual Winter Meeting was the first of a three-session set examining the status of various advanced reactors. The sessions were sponsored by the Operations and Power Division and chaired by Piyush Sabharwall of Idaho National Laboratory.

Presentation topics in the first session included the core design and helium Brayton cycle design of the Holos-Quad microreactor, a microreactor design for a truck charging station, and a levelized cost of electricity (LCOE) estimation on HALEU (high-assay low-enriched uranium) fuels for small modular reactors.

Here are some highlights:

A transformational challenge: Making crack-free yttrium hydride

Fabricated yttrium hydride samples are pulled out of the system. Photo: ORNL

Oak Ridge National Laboratory scientists have developed a method to produce solid yttrium hydride for use as a moderator for the Transformational Challenge Reactor (TCR), a 3-MWt additively manufactured microreactor that ORNL aims to demonstrate by 2023. Lacking a commercial supply of the metal hydride, ORNL scientists developed a system to produce yttrium hydride in large quantities and to exacting standards.

The hydrogen density and moderating efficiency of metal hydrides—which combine a rare earth metal with hydrogen—could enable smaller reactor cores that can operate more efficiently and reduce waste products, according to ORNL. The material could be used in other advanced reactor designs, including space power and propulsion systems for NASA, and has been proposed as a shield component for thermalization and neutron absorption in fast-spectrum nuclear reactors.

A microreactor at every rest stop?

The MiFi-DC as portrayed in a video released by Argonne.

Electrifying the nation’s trucking industry could reduce consumption of fossil-based diesel fuel, but it would also pose new challenges. A cross-country 18-wheel truck needs five to 10 times more electricity than an electric car to recharge its battery. Where will that electricity come from?

A team of engineers at Argonne National Laboratory has designed a microreactor called the MiFi-DC (for MicroFission Direct Current) that they say could be mass-produced and installed at highway rest stops to power a future fleet of electric 18-wheelers.

Nuclear News reached out to the MiFi-DC team to learn more. The team, led by Derek Kultgen, a principal engineer at Argonne who also leads the lab’s Mechanisms Engineering Test Loop, responded to questions by email. While they emphasized that much more needs to be done before the MiFi-DC could become a fixture at rest stops across the country, the information the team shared sheds some light on the process of designing a tiny reactor for a specific purpose.

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Argonne microreactor designed to charge long-haul trucks of the future

A team of engineers in Argonne National Laboratory’s Nuclear Science and Engineering Division have designed a microreactor called MiFi-DC that could be factory-produced and installed at highway rest stops across the country to power a proposed fleet of electric trucks. The reactors are described in an article, Could Argonne’s mini nuclear reactor solve the e-truck recharging dilemma? and a video released by Argonne on October 6.

Pairing a liquid metal thermal reactor with a thermal energy storage system, each reactor could fuel an average of 17 trucks a day.

Petition window opened for Oklo’s microreactor license application

The Nuclear Regulatory Commission has announced a notice of opportunity to intervene in an adjudicatory hearing on Oklo Power’s combined license application (COLA) for construction of a microreactor at Idaho National Laboratory. The notice, dated June 24, was published in the Federal Register on June 30, opening a 60-day window for petitions.

DFC plans to lift ban on nuclear plant financing

The U.S. International Development Finance Corporation (DFC) has initiated a 30-day public notice and comment period on a proposed change to the agency’s Environmental and Social Policy and Procedures that would allow it to consider support for nuclear power projects, according to a June 10 press release. Currently, DFC is specifically prohibited from offering support for such projects.

Comment now on advanced reactor GEIS scope

The Nuclear Regulatory Commission is developing a generic environmental impact statement (GEIS) for small-scale advanced reactor designs. Just how small a reactor must be to fit the parameters of the GEIS is one topic open for public comment, but the NRC staff anticipates including reactors generating up to 30 MWt. The public comment period is open until June 30

Defense Department invests in three microreactor designs

Three reactor developers got a boost on March 9 when they were each awarded a contract from the U.S. Department of Defense (DOD) to design a reactor that can fit inside a standard shipping container for military deployment. The DOD’s Strategic Capabilities Office (SCO), in partnership with the Department of Energy, proposes to build and demonstrate a 1–10 MWe reactor within four years that, if successful, could be widely deployed to support the DOD’s domestic and operational energy demands.