David, in another article -- "Feds asked to bring back nuclear Plan B", Canwest June 01, 2009 and http://www2.canada.com/topics/news/story.html?id=1652037 , which I assume appeared in print -- you took a shot at defining PCR and got it way wrong. Have you figured out what it really is, and corrected the record somewhere? I'm not suggesting that the correct definition makes it a total slam dunk that MAPLEs can't be operated unless they have a negative one, but I think it makes it more understandable that a negative one is inherently safer than a positive one. As you probably know, the entire trend of reactor design and regulation (especially since Chernobyl) has been toward "passive safety", and away from relying on engineered systems (like dual fast-shutdown systems) to compensate for inherent designed hazards (like the CANDU's positive void coefficient of reactivity). Licensing a reactor with a positive PCR would be bucking that trend. (But so is firing a regulator because an elected official promises that there won't be an accident!) While I'm writing: Have you at all looked into the economics of the Mo-99 business? I think all the world's Mo-99 is basically being given away almost for free, from ancient government-built reactors that would cost a fortune to rebuild (or repair!), and whose OPERATING costs aren't even being covered by the price of the Mo-99. As a result, this particular technology (Tc-99m) is "outcompeting" apparently better AND MORE COST-EFFECTIVE alternatives, like PET-scanners plus NaF-18 and maybe MRI or CAT scanners, all of which are sold by REAL businesses who insist on making REAL profits! I think that is ONE of the reasons why the rest of the world hasn't rushed into competition to make Mo-99 from new reactors. And have you looked at the OTHER reason, which is the nastiness of the process of extracting the Mo-99 from the target-rod-acid slurry, and the difficulty of dealing with the wastes? At least the way AECL does it (with HEU target rods), they are left with an acid slurry that contains much more than a critical mass of nuclear-weapons material, if it ever came out of solution. Does this sound, offhand, like a nice business for a nice country to get into, or to get out of? Sound like a good neighbour, somewhere near where you live?