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India To Build A Thorium Reactor 277

Posted by Unknown Lamer
from the someone-has-to-save-us-from-the-nimbys dept.
In their first story, slowLearner writes "India will build a working Thorium reactor. [Quoting the Guardian] 'Officials are currently selecting a site for the reactor, which would be the first of its kind, using thorium for the bulk of its fuel instead of uranium – the fuel for conventional reactors. They plan to have the plant up and running by the end of the decade.'" Before anyone gets too excited, this is only a modified Heavy Water Reactor and not one of those fancy Molten Salt Reactors folks like Kirk Sorenson have been evangelizing for a while now.
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India To Build A Thorium Reactor

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  • U != Th (Score:3, Informative)

    by unixisc (2429386) on Wednesday November 02, 2011 @10:38AM (#37920124)

    You are being too generic. Thorium doesn't have many of the disadvantages that Uranium has:

    • Weapons-grade fissionable material (233U) is harder to retrieve safely and clandestinely from a thorium reactor;
    • Thorium produces 10 to 10,000 times less long-lived radioactive waste;
    • Thorium comes out of the ground as a 100% pure, usable isotope, which does not require enrichment, whereas natural uranium contains only 0.7% fissionable U-235;
    • Thorium cannot sustain a nuclear chain reaction without priming, so fission stops by default.

    As a result, a lot of the safety disadvantages that one associates with Uranium based reactors are not applicable here. Thorium also cannot be weaponized, so it's unlikely that Iran, for instance, will be interested in this.

    For India, it's a fantastic deal, since that country has 25% of the world's Thorium resources (thank god, one doesn't have to depend on the Middle East for this). Also, the Thorium Energy Alliance (TEA), an educational advocacy organization, emphasizes that "there is enough thorium in the United States alone to power the country at its current energy level for over 1,000 years." Build a few plants in CA, NY, the Mid West and so on, and much of the commercial energy problems will disappear. In fact, if enough countries adapt this, the cash flow to OPEC will dry up, or at least considerably slow down.

  • Re:Well well (Score:5, Informative)

    by garyebickford (222422) <gar37bic@@@gmail...com> on Wednesday November 02, 2011 @11:42AM (#37921082)

    I worked on the control system for a nuclear plant maintenance robotic system back in 1990 (actually the controller was based on my design :) ). I learned something interesting about the nuclear power industry. The short version is - in France, nuclear power plants were considered machines, like airplanes. They were constructed and maintained like machines - they were all basically alike (in a given generation), and the differences were only in details of siting, etc. So each new one was just like the previous one, so everyone concerned knew pretty much how to avoid common problems like piping layout. And when a problem showed up in one, it would be fixed in all of them, much like FAA requires a problem in one 747 to be dealt with in every similar plane. (The paperwork for each 747, back when it was actual paper, weighed a significant fraction of the actual plane.)

    In the US, these plants were considered buildings, and were designed (mostly in the 1960s and early 1970s) by architects (using components, but put together in different ways). So every facility is different. The architects generally weren't familiar in advance so had to learn while designing. As a result, many plants have things like pipes that go through a walkway at waist high, so the workers have to climb over or under it, and pipes that had to be re-routed on-site (often halting construction for a period of time) because they collided with another one in the design. (These were all designed before modern CAD systems had the capability to catch that.) And, because they are all different, a problem in one may or may not be found in any other, so there's no easy way to pro-actively fix problems that are found in one plant, because the design may not match in the correct way.

    In an earlier job we were reviewing nuclear plant construction drawings with regard to the possibility of scanning them and generating CAD models. We found that the drawings in question were the worst engineering drawings we'd ever seen. They were essentially done without design rules, with multiple system layers all on one drawing - everything from concrete footers to electrical to plumbing all on one drawing, with pieces actually cut out and replaced by a redrawn section! I can't say that all plants were like this, but certainly this one was. It was unreadable by humans, much less computer scanners.

    The plants we were working with also had radically different cleanliness standards - they are all run by independent companies, with different rules and traditions. One plant was so clean that the whole radon-in-houses problem was identified when a worker set off the radiation detectors going IN to the plant. The interior radiation level was maintained substantially lower than the ambient in the area - the place made 'hospital clean' look like a swamp. Others, based on what we heard, were more like that guy down the street with the cars in his yard.

  • by dj245 (732906) on Wednesday November 02, 2011 @01:33PM (#37922744) Homepage
    Well, as a steam turbine engineer, their plan for the turbine is borderline ridiculous.

    The turbine system believed best suited for its operation is a triple-reheat closed-cycle helium turbine system, which should convert 50% of the reactor heat into electricity compared to today's steam cycle (~25% to 33%).

    Firstly, triple reheat turbines are more efficient from a thermodynamic point of view. But nobody builds them because the increased complexity and cost just aren't worth it. Double-reheat steam turbines were relatively rare for coal turbines- only a handful were built and the design concept was abandoned, but they may be common on the nuclear side.

    The next problem is using helium for the working fluid. I'm not saying it couldn't be done, but the turbine would have to be enormous in order to work with helium. I'm talking so big that you need to install the blades on site because you can't move it by road or rail. This adds a huge amount of extra cost also- assuming you can find a material to make blades that long with. Currently the longest blades for steam turbines available are Titanium 52" or maybe 60" (for 50hz systems). A longer blade would probably require an even stronger material with the desired properties, which does not currently exist at anything approaching a reasonable price.
  • by dj245 (732906) on Wednesday November 02, 2011 @01:37PM (#37922798) Homepage
    I don't usually reply to myself, but another problem with Helium is the tiny molecular size makes sealing pumps and other equipment difficult. In the case of the Fort St. Vrain [wikipedia.org] plant, it basically killed the project.

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