Lightbridge has developed an advanced metallic fuel, made from a zirconium-uranium (Zr-U) alloy, which uses a unique composition and fuel rod geometry enabling it to operate at a higher power density than uranium oxide fuels in use today. Current fuel comprises of uranium oxide pellets encased in zirconium alloy cladding which are bundled into fuel assemblies. The new fuel, the company says, can enable pressurised water reactors (PWRs) to operate at higher power outputs while also extending operating cycles, improving economics as well asproviding safety and fuel performance benefits.
Lightbridge president and CEO Seth Grae described the collaboration as an “important milestone” for the commercial advancement of the fuel.
According to a 2012 paper published in the American Nuclear Society’s peer-reviewed journal Nuclear Technology and reproduced on Lightbridge’s website, the alloy used in the fuel contains a zirconium content of nearly 50% by weight, but requires uranium enrichment levels of up to 20% – far in excess of typical uranium oxide fuels for PWRs, which are typically enriched up to 4.8% uranium-235. Reactor safety is enhanced thanks to the lower fuel temperature, increased heat transfer characteristics and improved cladding integrity offered by the fuel.
The company acknowledges that the fuel would not be suitable for use in all existing PWRs, citing constraints due to the size of existing reactor containments, but says that new-build projects could easily accommodate the necessary changes to allow them to use the innovative fuel.
The elevated enrichment levels, while within accepted bounds from a non-proliferation point of view, would necessitate infrastructure changes to existing enrichment and fabrication plants as well as amendments to plant licensing, fuel transport and storage.
Lightbridge is developing innovative, proprietary nuclear fuel technologies designed to significantly enhance the nuclear power industry’s economics and increase power output by:
Extending the fuel cycle length to 24 months or longer while simultaneously increasing the power output by up to 17% in existing pressurized water reactors (PWRs), including Westinghouse 4-loop reactors, which are currently limited to an 18-month fuel cycle;
Enabling increased reactor power output (up to 30% increase) without changing the core size in new-build PWRs
* Testing, design and validation of the metallic fuel is from 2013-2018
* Regulatory approval will be in the 2014-2018+ timeframe
* First commercial installation will be 1-2 years after regulatory approval
* The increased power generation will have a levelized cost of 20-30$ per MWH which is less than half the cost coal and natural gas and the regular nuclear construction
Lightbridge Corporation is developing an advanced metallic nuclear fuel capable of increasing the power output and extending the cycle length of current-generation light water reactors (LWRs). This paper provides a review of the unique geometry and composition of the metallic fuel and its application to power uprates in LWRs.
* The peer reviewed article to be published in December 2012 provides further validation of LTBR’s fuel technology
* Unique alloy and fuel rod geometry
* Increases power output by up to 17% in existing PWRs
* Extends fuel cycle to 24 months or more, enhancing industry economics
* Increased safety through lower operating temperatures
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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