X-energy pursues 50 MW pebble bed design

Amid all the interest in small modular reactors using well known light water technologies, occasionally fast reactor start-ups appear on the technological horizon. Several such start-ups have recently garnered media attention due to their focus on either molten salt or thorium fuel.

However, the so-called Pebble Bed high temperature gas-cooled reactor design, championed by South Africa until 2007, hasn’t gotten much attention in recent years. This is why a recent meeting of nuclear energy experts at a Greenbelt, MD, firm normally associated with NASA as gotten media ink.

X-energy, which is affiliated with NASA contractor Stinger Ghaffarian Technologies, Inc. recently convened a group of nuclear experts to discuss best-practices in pebble fuel fabrication. X-energy will use the spherical elements to fuel their Xe-100 50 MW gas-cooled (helium) nuclear reactor in the mid-2020s.

The Xe-100 will benefit from decades of research and safe operation in pebble bed reactors internationally. The designers claim the reactor will be able to power up, or down, depending on demand for electricity.

Conference attendees represented over 160 years of combined experience in pebble-bed reactor projects around the world, spanning the AVR and HTGR reactors in West Germany, PBMR in South Africa, and the HTR-10 currently in operation in China.

Mike Kania, nuclear fuel consultant and conference attendee, said: “Pebbles are a remarkable nuclear fuel source: a completely self-contained, ultra-safe package that can be added in during active operation – effectively eliminating refueling shutdowns. This time-tested pebble technology has enormous potential to expand safe, zero-emission nuclear energy worldwide.”

A 2013 online bio lists Dr. Mike Kania as an expert consultant on TRISO fuel who worked on it during his Oak Ridge career and later at Brookhaven.

Doug McCuistion, X-energy Chief Operating Officer, who also attended the meeting, is a busy man with on online bio that lists him as working on the NASA Mars Exploration program as a contractor.

The firm claims the compact Xe-100 is “ideally suited to locations with limited space or infrastructure, and its ultra-safe design allows siting close to population centers without risk to the public.”

Full details about X-energy and its target for commercial success in the early 2020s are available at the company’s web site.

Russia postpones work on BN-1200 related to fuel design issues

World Nuclear News reports  on 16 April 2015 in an extensive report with primary Russian sources that work has halted on the BN-1200 fast reactor in order to address technical issues with the fuel for the sodium-cooled design. Also, the report notes that the so-called GEN-IV reactor design is being reviewed from the perspective of cost-effectiveness.

The BN-800 series, a predecessor design, is a fast burner which use a uranium oxide fuel mixed with plutonium. One of the objectives of the design series is said to be to reduce Russia’s stockpile of surplus plutonium. In 2009 Russia inked a deal with China to supply two BN-800 units for commercial use.

Russia has built several other smaller similar fast reactors, but according to WNN, none of them have been put into commercial revenue service.

The original plan for the BN-1200 called for construction of three units at the Beloyarsk nuclear power plant in Zarechny in the Urals. Russia publishes an English language website on the BN series fast reactors.

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