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posted by martyb on Friday July 05 2019, @01:46PM   Printer-friendly
from the no-reactors-for-you! dept.

Nuclear reactors are seen emotionally as risky due to a few major accidents, but new technologies are coming which will potentially reduce the risks associated with it dramatically.

Commercial reactors have used the same fuel for decades: small pellets of uranium dioxide stacked inside long cylindrical rods made of a zirconium alloy. Zirconium allows the neutrons generated from fission in the pellets to readily pass among the many rods submerged in water inside a reactor core, supporting a self-sustaining, heat-producing nuclear reaction.

Trouble is, if the zirconium overheats, it can react with water and produce hydrogen, which can explode.

To reduce this risk,

[m]anufacturers such as Westinghouse Electric Company and Framatome are hastening development of so-called accident-tolerant fuels that are less likely to overheat—and if they do, will produce very little or no hydrogen. In some of the variations, the zirconium cladding is coated to minimize reactions. In others, zirconium and even the uranium dioxide are replaced with different materials. The new configurations could be slipped into existing reactors with little modification, so they could be phased in during the 2020s.

Core testing of some of these options is already underway and would have to be successful and regulatory hurdles overcome. Additionally, some of the options actually improve efficiency (and consequently cost-effectiveness) of plants. Sadly, 'Too cheap to meter' remains well off the table.

Modern plants, such as are being deployed by Russia both at home and abroad, now include

“passive” safety systems that can squelch overheating even if electrical power at the plant is lost and coolant cannot be actively circulated. Westinghouse and other companies have incorporated passive safety features into their updated designs as well.

Alternative cooling approaches not subject to hydrogen generation, such as Molten Salt (e.g. liquid sodium) and Helium are being tested and deployed. And very small modular reactors are being developed at the Idaho National Laboratory (the Russian state-run company Rosatom is making small reactors as well.)

a group of Western states has entered a tentative deal with NuScale Power in Oregon for a dozen of its modular reactors.

Mortality rates for various power generation methods in the U.S. shows nuclear power with a 50x lower mortality rate per unit power generated than the next safest option (hydroelectric) and 100,000 times lower rate than Coal, which provides much of the U.S. base power generation in its stead.

Still, nuclear power remains stalled in the U.S. and is being phased out in other countries such as Germany, leaving primarily Russia and China, both of which are deploying nuclear power aggressively, as the primary markets and beneficiaries of these new technologies.


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  • (Score: 4, Informative) by RS3 on Friday July 05 2019, @03:44PM

    by RS3 (6367) on Friday July 05 2019, @03:44PM (#863511)

    The "problems" all mentioned, including ones not mentioned, were solved 40 years ago in USA. Yet the general consensus remains that nuclear power is unsafe.

    The Three Mile Island (TMI) https://en.wikipedia.org/wiki/Three_Mile_Island_Nuclear_Generating_Station [wikipedia.org] accident was caused by the operators not definitely knowing reactor water levels, water flows, steam safety valve position, steam flow, etc.

    These problems were solved with new instrumentation which all reactors have now. No more guessing about reactor cooling, steam venting, etc. The instrumentation was available at the time of the TMI accident, but was optional (sounds a bit like the 737 MAX "disagree" indicator.)

    A phenomenal video on the topic: https://www.youtube.com/watch?v=1xQeXOz0Ncs [youtube.com] This video's main purpose is to convey problems with design processes, and the concepts apply to every design flaw ever.

    The biggest problem with nuclear power is cost. Excelon wants to close TMI 15 years ahead of its scheduled lifecycle. I highly advocate for many, but (much) smaller nuclear power stations.

    One of the big problems is that _any_ tiny change to anything in design or construction of a nuclear power station requires years of very expensive testing and certifications with piles and piles of accompanying paperwork.

    Chernobyl was a significantly different design than those used in USA and most of the rest of the world. They chose a lower cost design and either did not think things through, or proudly thought the problem could never happen.

    A phenomenal video on Chernobyl: https://www.youtube.com/watch?v=q3d3rzFTrLg [youtube.com]

    Fukushima is another example of arrogant design: critical safety cooling system generators were placed too low in the reactor building and when the tsunami was bigger than the tsunami wall, the generators got swamped, cooling stopped, and bad things happened. Perhaps they could learn some things from the people who build and run the swamp buggies? In any event, small-scale reactors are much more easily cooled, including passively with water stored in large tanks in a worst-case scenario.

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