Small fast reactor to offer 100 MW
It will be factory built with 20-year fuel loads and is based on the historically significant design of EBR-II
Among the many offerings being developed in the small reactor category, one has a unique legacy. Advanced Reactor Concepts LLC (ARC) is based on technology used over a 30-year period by the EBR-II program at Argonne National Laboratory-West (ANL-W) in Idaho.
The new product now under development in the Virginia suburbs of Washington, D.C., is a 100 MW liquid-metal (sodium) cooled fast reactor (large image) that will require refueling once every 20 years. It is remarkable that the technology of EBR-II will live again in this small reactor design. One of the pioneers of that technology, Leon Walters, is now working on the project and is interviewed here.
He told the American Nuclear Society (PDF file) in 2004 that those who built and operated EBR-II have not given up the vision. Walters notes, the design “is proven, it is proliferation-resistant, it decreases waste disposal problems, it’s inherently safe, and perhaps most important of all, Fermi’s original idea—conserving fissionable material—is still sound.”
The ARC reactor system comprises a small uranium-zirconium-fueled nuclear core, submerged in a tank of ambient pressure liquid sodium. The liquid sodium passes through the core where it is heated to 950 degrees Fahrenheit (510 degrees Celsius), it then passes through a heat exchanger where it heats sodium in an intermediate loop, which in turn heats working fluid for energy conversion turbines.
The working fluid can be water that is heated to create steam. Alternatively, the fluid can be carbon dioxide heated to create supercritical (almost liquid) carbon dioxide. The steam, or supercritical carbon dioxide, then spins a turbine to make electricity and is recycled in a closed loop for reheating. According to the company, the supercritical carbon dioxide energy converter system, called the Brayton cycle, provides a thermal efficiency (percentage of heat energy converted to electricity) of 40% or more, significantly higher than the efficiency of conventional steam driven turbine systems.
This blog spoke with Irfan Ali, CEO, (left) about the project. While ARC is privately held, he was willing to share some details about the reactor. Ali said the reactor will come in two sizes – 50MW and 100 MW. The 100 MW design will be described in two papers to be presented at the June 2010 meeting of the American Nuclear Society (ANS) to be held in San Diego, CA. The release of the papers at the ANS meeting will also mark the simultaneous commercial roll-out of the company’s marketing efforts.
Ali said the ARC reactor is intended for distributed power applications for remote sites such as mining camps, military bases, other off-the-grid applications, and for water desalinization. Unlike other small reactor designs, it is not expected that customers will bundle them in six packs. Instead, the reactors will be used one-at-a-time with the possibility of a second unit for backup. The small size of the reactor will allow it to be shipped by rail or barge to a customer site.
Plug in-Pull out-Plug-in
According to the company web site, and the interview with Ali, replacement of the fuel will be simple. The entire fuel assembly comes out like a flashlight battery, or the cartridge from a ball point pen, and a new one pops into place ready for use. This feature is a competitive advantage for the ARC reactor because it addresses issues related to nonproliferation of fissile materials and waste management. Ali added that the design follows that of EBR-II which has been shown to be inherently safe in a series of ground-breaking experiments.
For instance, in response to accident conditions such as loss of coolant flow to the reactor or loss of the ability to reject heat from the reactor system, the reactor safely shuts itself down without human or safety-system intervention, and without sustaining any damage to the core or other components, so that it can be returned to service as soon as the problem has been cleared. These characteristics allow it to be operated with simplified controls.
ANL pioneer advances latest incarnation of EBR-II technology
Leon Walters, now Vice President for Fuel Design at ARC, was Director of Fuels & Materials and also Fuel Design at Argonne West. He led the development of fuels and materials for fast reactors over a 34-year career, concentrating on metal fuel, which is the fuel of choice for the ARC reactor. Its development involved many innovations, which were then proven in irradiation testing of the EBR-II.
In an exclusive interview with this blog, Walters (right) said that the 20-year fuel cycle of the ARC reactor design is facilitated by a low burn-up rate. He said that the core design has just been completed, but he declined to say much more about the fuel other than it is a uranium-zirconium mix that will be well understood by the NRC. However, getting a U.S. certification will be a challenge, Walters said, because the NRC's Part 52 Standard Review Process is oriented to light water reactors.
The company's technology is now patent pending. Walters said that the firm plans to publish two papers – one on core design and another on fuel – at the June 2010 meeting of the American Nuclear Society to be held in San Diego, CA. He likened the ability to swap out the fuel assembly to "changing the batteries in a flashlight." He says this is a simpler approach than other small faster reactors coming to market though they also promise customers “plug-and-play” designs.
Investor and customers development
CEO Ali said the company is currently funded privately, and declined to name any of its investors, but it has an impressive management team. The firm was started by Don Wolf, a venture capitalist, and Scott Campbell, (bio) an international energy policy expert, former CEO of an international energy consulting firm, and a former senior U.S. Department of Energy official.
Paul Robinson, the former head of Sandia National Laboratory, is Vice-Chairman of the company's board of directors. CEO Ali has a background in high technology including commercial and defense-related optical telecommunications.
The firm expects to begin preliminary design certification discussions with the NRC in 2010, but the first customers will likely be outside of the U.S. However, the plan is to manufacture the reactor and its fuel elements in the U.S. Ali declined to discuss details of the type of fuel the reactor will use, but did say it will be enriched at 15%. In the interview with Walters, he said the fuel will be available to meet customer specifications at multiple levels of enrichment with 15% being an average figure.
As far as the market for distributed power is concerned, Ali said the market for small reactors is very segmented and there are opportunities for small reactors to meet customer requirements for distributed power. Ali says he knows there are many challenges ahead to get his product to market. For the next year the company is focused on raising money through private sources and developing the technology. He promised to keep readers of this blog appraised of how things are going.
Advanced Reactor conceptual design
Idaho Samizdat is a blog about the political and economic aspects of nuclear energy and nonproliferation issues. It covers the nuclear energy industry globally. Additionally, the blog has regional coverage on uranium mining in the western U.S. Link to original post
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