ANSI/ASME/ANS RA-S-1.4-2021, “Probabilistic Risk Assessment Standard for Advanced Non-Light Water Reactor Nuclear Power Plants,” has just been issued. Approved by the American National Standards Institute (ANSI) on January 28, 2021, this joint American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) standard sets forth requirements for probabilistic risk assessments (PRAs) used to support risk-informed decisions for commercial nuclear power plants and prescribes a method for applying these requirements for specific applications.

ANSI/ANS-RA-S-1.4-2021 and its preview are available in the ANS Standards Store.

Rendering of the proposed Versatile Test Reactor. Image: Idaho National Laboratory

The Department of Energy won’t publish its draft environmental impact statement (EIS) for the Versatile Test Reactor (VTR) until mid-December. In a November 19 announcement on Twitter, however, the DOE’s Office of Nuclear Energy said that the yet-to-be-released EIS lists Idaho National Laboratory as the preferred alternative to site the VTR.

The DOE plans to submit the draft EIS for public comments early next month. The DOE won’t make a final decision on the design, technology selection, and location for the VTR until the completion of the EIS and record of decision in late 2021.

Illustration of Core Power’s modular MSR concept. Image: Core Power

Core Power is a tiny startup that is bullish on the prospects for nuclear-powered ocean transportation. The company announced on November 2 that it is part of a team that has applied for a cost-shared award from the Department of Energy’s Advanced Reactor Demonstration Program (ARDP) to build a prototype molten salt reactor (MSR). Core Power believes that MSRs could be used for propulsion or electricity generation to decarbonize the world’s commercial shipping fleet.

Based in London, England, Core Power is the only non-U.S. member of the team, which includes TerraPower, Southern Company, and Orano USA. As a marine engineering firm, Core Power says that it offers its ARDP partners “access to pent-up demand from a market with real customers.” An announcement of ARDP “risk reduction for future demonstrations” award winners is expected in December.

Clockwise from top left are Craig Piercy, Ray Furstenau, Tom O’Connor, Sean McDeavitt, Tara Neider, and Judi Greenwald.

The Versatile Test Reactor’s conceptual design was approved in September, and a draft environmental impact statement could be released within the week. The completion of more project milestones leading to operation in 2026, however, will depend on congressional appropriations. An expert panel described the need for a state-of-the-art test reactor and the value that the VTR could bring to the U.S. nuclear R&D community over its 60-year lifetime during a recent webinar—“Advanced U.S. Nuclear Research and Development: A Briefing and Discussion on the VTR”—hosted by Idaho National Laboratory.

Craig Piercy, ANS executive director/CEO, moderated the webinar, introducing a project update from VTR executive director Kemal Pasamehmetoglu and facilitating a Q&A session with representatives of the Nuclear Regulatory Commission, the Department of Energy, universities, reactor developers, and the Nuclear Innovation Alliance. A recording of the October 29 webinar is available online. INL also has a video and information online on the VTR.

“I think that the VTR represents part of a larger effort to modernize our infrastructure, develop a new set of technologies, and really preserve our global leadership in the field,” said Piercy. Read on to learn more about the promise the VTR holds for the nuclear community.

A fissile material handler uses a shielded glovebox to dissolve U-233 into a low-level form so that it can be mixed with grout for safe transportation and disposal. Photo: DOE

The processing and downblending of uranium-233 for disposal has resumed at Oak Ridge National Laboratory, following a pause in operations due to the COVID-19 pandemic, the Department of Energy announced on October 20. Removal and disposition of the U-233 is one of the DOE Office of Environmental Management’s highest priorities at the site, as stated in its strategic vision released earlier this year.

The project is removing a significant risk by eliminating the inventory of highly enriched fissile material stored in Building 3019, the world’s oldest operating nuclear facility, according to the DOE. Employees, known as fissile material handlers, use shielded gloveboxes to dissolve U-233 into a low-level form so that it can be mixed with grout for safe transportation and disposal. The material dates back decades and was originally pursued as a fuel for reactors; however, it did not prove to be a viable option.

After talking about it for decades, the United States is finally ready to take the next step in demonstrating advanced reactor technologies.

We have the bipartisan support from Congress. We have the best innovators in the world. Now it’s time to see what U.S. nuclear companies can really do with the support and resources of the federal government.

The U.S. Department of Energy is all in on new nuclear technologies and we just made our boldest move yet—selecting and supporting two U.S. reactor designs that will be fully operational within the next 7 years.

After evaluating the competitive U.S. reactor design applications that were submitted to our new Advanced Reactor Demonstration Program funding opportunity announcement, TerraPower LLC and X-energy were awarded $160 million in initial funding to test, license, and build their advanced reactors under this aggressive timeframe. Pending future appropriations by Congress, the DOE will invest $3.2 billion over 7 years in these projects that will be matched by the industry teams.

The Department of Energy has put two reactor designs—TerraPower’s Natrium and X-energy’s Xe-100—on a fast track to commercialization, each with an initial $80 million in 50-50 cost-shared funds awarded through the Advanced Reactor Demonstration Program (ARDP). In all, the DOE plans to invest $3.2 billion—with matching funds from industry—over the seven-year demonstration program, subject to future appropriations.

Energy Secretary Dan Brouillette announced the awards late in the day on October 13 in Oak Ridge, Tenn., and said, “These awards are a critical first step of a program that will strengthen our nation’s nuclear energy and technological competitiveness abroad, and position our domestic industry for growth, for increased job creation, and for even more investment opportunity. It’s absolutely vital that we make progress on this technology now.”

The proposed Versatile Test Reactor complex would cover about 20 acres. Image: INL

Now that the Department of Energy has approved Critical Decision 1 for the Versatile Test Reactor (VTR) project, the engineering design phase can begin once Congress appropriates funding, according to a September 23 announcement from the DOE’s Office of Nuclear Energy. The DOE has requested $295 million for the project in fiscal year 2021.

The news came nearly one month after a team led by Bechtel National Inc. (BNI), and including GE Hitachi Nuclear Energy (GEH) and TerraPower, entered into contract negotiations with Battelle Energy Alliance (BEA) for the design-and-build phase of the VTR. GEH’s sodium-cooled fast reactor PRISM technology was selected to support the VTR program in November 2018.

Three companies that are part of a larger collaboration to develop and demonstrate Natrium, the fast reactor design recently introduced by TerraPower and GE Hitachi Nuclear Energy (GEH), were invited to participate in a webinar hosted by ClearPath to talk about Natrium’s design, fuel requirements, and load-following potential.

The September 21 webinar, titled “Natrium: Latin for Sodium, Big for Advanced Nuclear,” was moderated by Rich Powell, executive director of ClearPath, and featured TerraPower’s Chris Levesque and Tara Neider, Centrus Energy’s Dan Poneman, and Duke Energy’s Chris Nolan.

TerraPower announced on September 15 that it plans to work with Centrus Energy to establish commercial-scale production facilities for the high-assay, low-enriched uranium (HALEU) needed to fuel many advanced reactor designs.

The proposed investment in HALEU fuel fabrication is tied to a TerraPower-led submittal to the Department of Energy’s Advanced Reactor Demonstration Program (ARDP), which was created to support the deployment of two first-of-a-kind advanced reactor designs within five to seven years. TerraPower would like one of those designs to be Natrium, the 345-MWe sodium fast reactor that it has developed with GE Hitachi Nuclear Energy.

An artist’s rendering of Natrium. Image: TerraPower

The Natrium reactor and energy system architecture, recently introduced by TerraPower and GE Hitachi Nuclear Energy (GEH), offers baseload electricity output from a 345-MWe sodium fast reactor with the load-following flexibility of molten salt thermal storage. Stored heat can be used to boost the system’s output to 500 MWe for more than five and a half hours when needed, according to TerraPower. A company representative told Nuclear News that the company expects a commercial Natrium plant to cost $1 billion or less.

Artist’s rendering of the Versatile Test Reactor. INL Image

A team led by Bechtel National Inc. (BNI) that includes GE Hitachi Nuclear Energy (GEH) and TerraPower is in contract negotiations with Battelle Energy Alliance (BEA) for the design-and-build phase of the Versatile Test Reactor, BEA announced on August 24. As planned, the VTR would support irradiation testing of fuels, materials, and equipment designed for advanced reactors.

This vial contains traces of actinium within a mixture of thorium and uranium. Photo: Isotek

An article recently published in Chemical & Engineering News describes TerraPower’s efforts to extract actinium-225, a radioisotope with therapeutic potential, from highly radioactive uranium-233 owned by the Department of Energy and slated for disposal. While others are working to ramp up production of Ac-225 by using a linear accelerator or cyclotron, TerraPower hopes to harvest between 200,000 and 600,000 doses a year from U-233 to increase the global supply.