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Small Modular Reactors

  1. Feb 20, 2014 #1
    I am in a concepts of nuclear physics course (going for a nuclear physics degree) and we need to do a paper and presentation on a topic. What I picked was small modular reactors.

    I was wondering if people had links to papers on new technologies, engineering ond concepts in development or currently working. It's a VERY broad topic, so I am mostly brain storming for a good concept. I am most interested in idea's relating to safe use of them in public spaces but any and all information is welcome.

    One last thing, I am NOT looking for my work to be done for me, so I would like primary sources and summary articles please. This is a 3rd year physics course that is open to anyone needing to work with radiation physics (engineering, and medical sciences in this) so the math isn't as important, it's more understanding of the concepts.

    Thanks you in advance for any help provided!
  2. jcsd
  3. Feb 21, 2014 #2


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    Staff: Mentor

    The small modular reactors have a name, but it escapes me now. Do you know the name?
  4. Feb 21, 2014 #3


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    Gold Member

    A starting point might be this writeup of the players involved:

    The appeal of the SMR is lower cost, because the product is produced in series rather than as a set of one offs,
    as well as greater safety because the standardized design and smaller size makes training and accident management easier. Whether these benefits are actually achieved given regulatory and industrial constraints remains TBD.

    Weinberg, who was keenly aware of the limitations of prevailing reactor designs, tried during his tenure to advance liquid fueled reactors. Those efforts died afaik with his dismissal, but would still be well worth a fresh look.
  5. Feb 22, 2014 #4


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    The US NRC has pages on advanced and modular reactors, including small modular reactors.

    The convention for small has been set at 300 MWe. They vary from ~45 MWe per unit to ~300 MWe. Note that those designs before the NRC are typically some type of PWR, and most likely 17x17 assembly lattice designs, as this is proven technology.

    There are some more exotic concepts based on graphite-moderated gas-cooled and fast, liquid-metal-cooled technologies.

    Basically, the safety issue is addressed with small cores. There are passive safety features to the extent possible, but assurance of coolability and reactivity control (shutdown capability) are still mandatory. Certain types of LWR accidents may be precluded by design.

    One issue for multiple modules on one site will be the impact or affect of an accident in one modular on the 'safe' operation of the other moduels.

    The idea of a modular system is that a single module can be built at less capital cost than a large single unit, and the modules can be staggered such that one can be online while the others are in various stages of completion, i.e., a utility does not have to complete all construction before generating revenue, part of which will offset the capital cost of subsequent units.

    SMRs are based on the same principles as the larger commercial nuclear reactors. There is a core containing fissile material. The core sustains a controlled chain reaction in which fissile isotopes (U-235, and potentially, U-233, Pu-239,240,241, . . . TU) are fissioned over some period of time. In some designs, long irradiation periods are envisioned, with some strategies replacing the entire core in one refueling outage.

    The nuclear thermal energy (heat) is tranferred from the fuel through the coolant to a thermal-to-mechanical conversion system, basically a steam turbine, which is coupled to an electrical generator.
    Last edited: Feb 22, 2014
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