Re: Small Nuclear Power Reactors

[Jones Beene]

As for some rough cost numbers, if you figure that a medium size 700 MW Candu reactor with 100 tons of heavy water is loosing a tenth of a percent of that mass per year, in the form of D-O-D degrading to H-O-D then that's 200 lbs of water, or over 10 pounds of neutrons. In general, the waste heat of the reactor can be used to bring this degraded D2O back up to "reactor" grade via ongoing enhanced thermochemical distillation methods. You will still need to add 200 pounds of makeup reactor-grade heavy water, however at about $3 million/ton. Not much really compared to the "value" created by the degraded tenth-percent. To wit: 10 lbs-equivalent of neutrons will enrich well over a ton of natural uranium or thorium from fertile to fissile. For fissile Uranium, the heat content = 3.3 x 10^10 Btu/lb  = ~6.6 x 10^13 Btu/ton which is more than a years supply of fuel for this plant !!  For comparative purposes, the heat content of bituminous coal, the cheapest source of energy in common use, is about 3 x 10^7 Btu/ton and a ton costs $40 here and much less in China. To equal a ton of U burned, the comparative amount of coal would cost about $80 million. This is the value of the "free" neutrons since the comparative plant would burn a net of $80 million of coal per year (based on the US coal price) and since the "free" neutrons from a deuterium moderator will ideally enrich well over a ton of natural uranium or thorium from fertile to fissile. For every 1000 KWe or power - then per day one needs: Coal: 9000 tons/day  or $360,000/day Uranium (as 235U) only 3 kg/day ... with "free" neutrons and natural U at $50/kg, this is $150/day fuel cost.   Net saving per year is nearly the whole $80 million. At the very least, then, the "hidden" value of the Candu in comparison to even coal is the full $80 million yearly less the difference in capital cost - as the price of natural U is so low. Over a 30 year life of the plan, this is as much as $2.4 billion if coal stays the same price. In practice, this "savings" will increase comparatively over the years, as the cost of coal increases when supplies decrease. BTW Atomic Energy of Canada is advertising to the world that  they will come to your site and install a pair of the newer reactors at just over US $1,000/ kilowatt capacity for capital cost. A recent project in Quinshan China finished with two Candu's in 46 months, on-budget and ahead of schedule. These two fully fueled and operational were $3 billion net, including fuel and heavy water which is about 20% of the net cost. These numbers are from press reports.   Many critics of AEC said it was too much of a bargain for China, which not exactly an ally - and a "giveaway" to a potential enemy, and bad deal for Canada (since AEC changes the government of Canada even more !!)...   ... but AEC is happy with the price, and like all good citizens, they do not mind gouging the mother-lode, and have apparently taken orders for 4 more of them to China, and is even financing them, based on the value of the US dollar...poor China! They do not appreciate how fast the dollar is dropping.   All in all, I think it must be a fair price on the international market. Now, if power generators in the USA could get such a deal we could all charge up the new hybrid Prius on the cheap for years to come! (is the plural of Prius - Prii?)   The modular reactor described earlier in this thread will not compete with Candu on the international market, where the financing charges are borne by the manufacturer and not by the utility - but in the USA - just eliminating the interest (modularity would do that) would make the concept very competitive, plus - getting away from steam should make it safer and more desirable than Candu - even if less efficient.   When your fuel cost, due to using natural uranium, is essentially "chump-change" and you also eliminate carbon altogether (for the ecological benefit), then you do not worry all that much about actual efficiency. Even if the efficiency dropped from 35% (Candu) to 17% (advanced thermoelectric) then the fuel cost only goes up from $150/ day to $300/day for about half a million consumers and lots of free thermal heat becomes available for factories and winter use. Jones