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

November 20, 2020, 1:04PMNuclear News

“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 microreactor design: Nicholas E. Stauff, of Argonne National Laboratory, presented information about the core design of the Holos-Quad microreactor, a concept proposed by HolosGen to generate 10 MWe with a lifetime of approximately eight effective full power years. The design is based on a high-temperature gas-cooled reactor concept using four subcritical power modules, each containing its own power conversion system executing a closed-loop Brayton cycle. The full system is designed to fit into one commercial 40-foot transport container for ease of delivery.

“It is designed with a strong emphasis on economic performance, which drove the selection of a high-temperature operation target to reach a plant efficiency that makes the design economically sustainable and competitive in the market,” Stauff said.

A Brayton cycle design: Anton Moisseytsev, also of ANL, followed Stauff with a description and analysis of the Holos-Quad’s closed-loop helium Brayton cycle design. “The work I presented here was done for examining design conditions,” Moisseytsev said. “But now the work is being extended to a transient analysis, which will include both reactor and Brayton cycle designs. In the longer term we will conduct a transient analysis under accident conditions.”

MiFi-DC generator: Stauff gave a second presentation in the session that focused on microreactor design for a truck charging station. Motivated by the immense use of fossil fuels in the truck transport industry, researchers at ANL began investigating microreactors as a source of thermal energy, which can be coupled with a thermal storage unit and used to drive a heat engine for electrical production at rest stops. The micro-fission direct current (MiFi-DC) generator would be mass produced in a factory, shipped via semitruck, and installed partially underground near rest stops across the country.

“Our preliminary feasibility study of the MiFi-DC core concept showed what I consider to be very attractive results,” Stauff said. “It is a very compact system with a long lifetime. It is a simple design that we think will lead to a very high level of safety. And the design can be adapted to a wide range of operating temperatures, which enables the use of different heat storage systems.”

A case study: The session concluded with Liam Carlson, of Virginia Commonwealth University, providing an LCOE estimation using NuScale’s 160 MWt SMR concept as a case study. The LCOE for a nuclear power plant is the price of electricity generated by a plant where revenues would equal costs, indicating a return on the capital invested equal to the discount rate, often expressed in units of $/MWh.

Carlson said that the average LCOE estimated for NuScale’s SMR is approximately $86/MWh. He added that the increase in total fuel costs due to higher enrichment may only be considered economically viable if the resulting LCOE is no more than the original design and available competing power generation technologies.

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