Four major announcements were made this week by developers of advanced nuclear reactors in the U.S. All of them indicate progress towards completing designs and engagement with nuclear safety agencies.

There are significant distinctions between them in terms of technical details of the designs and there are also a range of commitments in terms of the key success factor – paying customers.

• GE Hitachi Nuclear Energy (GEH) and Advanced Reactor Concepts LLC (ARC) Nuclear signed a memorandum of understanding (MOU) to jointly develop a reactor design intended for global markets. Initial deployment will be in Canada.
• Southern Nuclear and X-Energy announced it has started the conceptual design phase of its high-temperature-gas cooled reactor (HTGR). Southern Nuclear named Clint Medlock, a 27 year nuclear veteran, as program manager.
• NuScale Power LLC announced that the U.S. Nuclear Regulatory Commission (NRC) has accepted the firm’s Design Certification Application (DCA). The NRC said the DCA addresses all of the agency’s requirements and contains sufficient technical information to conduct the review.
• Thorcon / Martindale reports it is in discussions with the Indonesia National Nuclear Energy Agency about its molten salt reactor design. The firm said its has completed a technical assessment of the cost competitiveness of its reactor compared to coal power plants.

GEH ARC MOU

GE Hitachi Nuclear Energy (GEH) and Advanced Reactor Concepts LLC (ARC Nuclear) have agreed to collaborate in the development and licensing of an advanced small modular reactor (aSMR) based on mature Generation IV sodium-cooled reactor technology.

In a Memorandum of Understanding (MOU), the two companies have agreed to enter into a collaboration to progress a joint aSMR design for global power generation with initial deployment in Canada.

The companies will pursue a preliminary regulatory review by the Canadian Nuclear Safety Commission (CNSC) through its Vendor Design Review process. The joint effort has the near-term goals of confirming projected construction and operating costs, as well as the identification of a lead-plant owner/operator for the joint aSMR.

GEH and ARC Nuclear have each developed advanced reactor designs based on the EBR-II, an integral sodium-cooled fast reactor prototype which was developed by Argonne National Laboratory and operated successfully for more than 30 years at a site located about 25 miles west of Idaho Falls, Idaho. No U.S. fast spectrum reactor technology has more test data, design maturity, programmatic information, or operational experience.

These two reactor designs — GEH’s PRISM and ARC Nuclear’s ARC-100 — have been focused on different objectives. The ARC-100 is a 100 MWe aSMR designed to operated for up to 20 years without the need for refueling. In comparison, PRISM, which is designed to refuel every 12 to 24 months, has primarily been focused on closing the fuel cycle by, among other things, consuming transuranics, including surplus plutonium from decommissioned nuclear weapons and from spent nuclear fuel. Both these aSMR designs nevertheless share fundamental features, such as high energy neutrons, liquid sodium cooling and metallic fuel.

World Nuclear News, in its report on the collaboration, reported that GEH’s Prism reactor has a rated thermal power of 840 MWt and an output of 311 MWe. Two Prism reactors make up a power block, producing a combined total of 622 MWe of electrical output.

Using passive safety, digital instrumentation and control, and modular fabrication techniques to expedite plant construction, the design uses metallic fuel, such as an alloy of zirconium, uranium, and plutonium.

It can therefore be used to close the nuclear fuel cycle, recycling used nuclear fuel to generate energy. It is designed to be refueled every 12-24 months. GEH has previously proposed the Prism reactor as a possible option for managing the UK’s plutonium stockpile.

ARC’s ARC-100 modular 100 MWe model would use a ‘novel’ metal alloy fuel, with the uranium-fuelled reactor core submerged in a tank of liquid sodium at ambient pressure. It would have a refueling interval of 20 years.

Last October, GEH and Southern Nuclear signed an MOU to collaborate on the development and licensing of fast reactors including GEH’s Prism. The companies also agreed to work together in future US Department of Energy advanced reactor licensing programs.

X-Energy Reactor Moves to Conceptual Design

X Energy, LLC (X-energy) announced that it has commenced the conceptual design phase for its Xe-100 high temperature gas-cooled (HTGR) pebble bed modular reactor.

X-energy held a Conceptual Design Readiness Review on March 8th to validate the baseline design parameters, preparatory documentation, analysis tools, scope of the proposed conceptual design phase (including all planned deliverables), management processes and overall team readiness to proceed on to the next phase of Xe-100 reactor development.

An external panel comprised of industry experts from Southern Nuclear, Burns & McDonnell, and Technology Insights was engaged to evaluate X-energy’s preparedness to enter the conceptual design phase.

As part of the conceptual design, X-energy and Southern Nuclear deepened their relationship by engaging Clint Medlock on X-energy’s Xe-100 development team as Program Management Consultant. Medlock, a 12-year Southern Nuclear veteran, has 27 years’ nuclear industry experience and has managed several large nuclear design and construction projects.

In its report on the milestone, World Nuclear News added details about the reactor. The Xe-100 is a 200 MWt (75 MWe) reactor, which X-energy envisages being built as a standard “four-pack” plant generating about 300 MWe. The plant will use ‘pebbles’ of fuel containing Triso (tristructural-isotropic) fuel particles.

Each Triso particle has a kernel of uranium oxycarbide (uranium dioxide) enriched to 10% uranium-235, encased in carbon and ceramic layers. About 25,000 Triso particles, each about 0.4 millimeters in diameter, are embedded in graphite to produce spherical fuel pebbles. About 17,000 pebbles will be used in each reactor. X-energy is working to master the pebble pressing process.

Triso fuel’s carbon and ceramic layers prevent the release of radioactivity, providing each particle with its own independent containment system, while the graphite surrounding the particles moderates the nuclear reaction. Such fuel cannot melt down and X-energy describes the reactor as “walk-away” safe in the event of a loss of coolant.

All of the plant’s components will be road-transportable, streamlining construction by enabling the plant to be installed, rather than constructed, at the project site.

NuScale Power, LLC Design Accepted for Review by U.S. NRC

NuScale Power, LLC announced this week they received notification that NuScale’s first-ever Small Modular Reactor (SMR) Design Certification Application (DCA) was accepted for review by the U.S. Nuclear Regulatory Commission (NRC). By accepting the DCA for review, the NRC staff is confirming that NuScale’s submission addresses all NRC requirements and contains sufficient technical information to conduct the review. NuScale marked a major milestone on December 31, 2016 when the company asked the NRC to approve the SMR design, the first submitted in the United States.

When NuScale announced the application submittal in January, the NRC had targeted completing the certification process for the NuScale SMR power plant design in 40 months from acceptance. NuScale’s application consisted of nearly 12,000 pages of technical information, representing the work of more than 800 NuScale staff and some 40,000 NRC staff-hours in pre-application discussions and interactions.

The first commercial NuScale power plant is planned for construction on the site of the Idaho National Laboratory for the Utah Associated Municipal Power Systems (UAMPS) and operated by experienced operator Energy Northwest.

Conservative estimates predict approximately 55-75 GW of electricity will come from operating SMRs around the world by 2035, the equivalent of more than 1,000 NuScale Power Modules.

NuScale is the first company to submit a small modular reactor design for certification. SMR designs seek to meet NRC safety requirements through smaller reactor cores and passive safety features. The NRC, after completing its acceptance review, has concluded NuScale’s application is complete enough for a full design certification review. The staff soon will provide a review schedule.

The NRC’s certification process determines whether a reactor design meets U.S. safety requirements. Companies can then reference a certified design when applying for a Combined License to build and operate a reactor in the United States. The NRC’s Advisory Committee on Reactor Safeguards provides input on design certification reviews. If issued, certifications are valid for 15 years.

ThorCon Molten Salt Reactor Study Results Released

(NucNet) Three state-owned Indonesian companies – Pertamina, PLN and Inuki – have completed a technology pre-feasibility study which has concluded that a molten salt reactor design proposed by US-based Martingale could deliver safe, cheap, clean energy. The report claims the reactor could be built now, would be economically viable, and would have the potential to replace coal power plants.

Martingale signed an agreement in 2015 with the Indonesia Thorium Consortium to develop the ThorCon reactor with Indonesia. The ThorCon team has now begun discussions with Indonesia’s National Nuclear Energy Agency (Batan) to review the ThorCon design. If Batan approves the design it will recommend to the government that ThorCon be Indonesia’s first nuclear power plant.

The Indonesia Nuclear Professional Association has agreed to be project manager for a technical assessment of the technology. ThorCon representative Bob Effendi  said the technical assessment will enable the Indonesian government to “open the door” for nuclear power, as called for in a national plan which says nuclear power plant construction should start in 2019 and be operating by 2025.

ThorCon is a liquid-fuel nuclear reactor design, which uses uranium and thorium fuel dissolved in molten salt. ThorCon requires no new technology because it is a straightforward scale-up of the successful molten salt reactor experiment (MSRE) at the Oak Ridge National Laboratory in the US and is using the MSRE as its pilot plant. There is no technical reason why a full-scale 250-MW prototype cannot be operating “within four years,” Martingale said.

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