Hi, While googling around further, I came across this reference: http://www.springerlink.com/content/882432575m335467/ That sounds significant. 210Po is supposed to be a significant alpha emitter, and has been used in Radioisotope Thermal Generators. So enhancing its decay rate by 5-8% means significantly more energy output. However, I'd imagine it would be difficult to drain the heat off a nuclear fuel element fast enough to keep it at 12K. But still, wouldn't it be an interesting idea?