Nuclear Technology / Volume 184 / Number 2 / November 2013 / Pages 169-180
Technical Paper / Fission Reactors
To achieve long-term energy security in an environmentally acceptable manner, fission technology needs to make further advances in the areas of lower financial risk, better resource utilization, and reduced volumes of high-level waste. Without such progress, these concerns may be limiting factors in the exploitation of this vital resource. "Convert-and-burn" fast reactors offer the potential for advances in each of these areas without the specter of increased proliferation risk that accompanies breeder reactor concepts. An example is Energy Multiplier Module (EM2), a compact, helium-cooled fast reactor that augments its fissile fuel load with either depleted uranium or used nuclear fuel (UNF). The convert-and-burn in situ operating mode results in a core predicted to last 30 years without the need to add or shuffle fuel. EM2 can endure a station blackout, even one combined with a loss-of-coolant accident, using only passive safety systems to prevent radioactivity release or loss of plant. The end-of-cycle fuel and/or light water reactor UNF can be refabricated in a manner that does not separate out heavy metal, permitting reuse in subsequent generations at reduced proliferation risk. Proliferation resistance is further enhanced by eliminating the need for enrichment beyond that needed for the first-generation fuel load. Waste problems are mitigated by several factors: higher burnup, fuel use in multiple generations, and conversion of existing waste to energy. Economically attractive power costs are anticipated through a combination of high efficiency, simplicity of the direct-cycle gas turbine, and relatively small subsystems that can be shop fabricated and shipped by road to the site. Reactor materials have been carefully chosen to achieve a safe, economically affordable, and proliferation-resistant energy source.