1. Rod, Chris Mowry points out the safety advance of the mPower:
    “With our design, the core never gets uncovered under any postulated design-basis accident. That is an incredible step forward from a safety perspective and greatly simplifies and reduces the challenge that you need to address with an emergency core cooling system. That is a separate result of the innovative approach with an integral NSSS.”
    “Because you can have a much simpler passive safety system, that takes cost out of the nuclear island on the safety side. When you shrink down a plant, typically you

  2. Rod,
    Looking at the picture of the four unit plant reminded me of my time spent working on an eight unit plant that had four engine rooms with the capability of cross-tieing steam and electrical systems throughout the plant. 49 years later the “Big E” is still in service although it looks like 2012 is scheduled for the USS Enterprise’s official decommissioning. It’s amazing what you can do with a couple of small reactors. Maybe it’s time for the commercial nuclear industry to apply a similar design.

    1. So Jim, maybe you want to tell me the cost of making electricity on the “Big E” before suggesting that the commercial nuclear industry should adopt a similar design.
      Do navy nukes still hook up to shore power whenever possible?
      Fascinating reading about paper reactors is one thing, producing huge amounts of electricity is another.

      1. You really don’t like small reactors, do you Kit? Well don’t worry. If you’re right, you can tell us that you told us so somewhere down the track.

      2. Kit,
        The last navy study that I saw showed the breakeven cost of nuclear power for a large surface combat vessel was when oil is north of $80/barrel. We will probably be well above that in a few years.

    2. Jim,
      The Enterprise will have pretty much run out its final core set. Refueling at this age would be like giving a heart transplant to a 90 year old.

  3. I loved every small reactor I operated. They made the ship go fast. Small reactors are great for naval propulsion. Size is important and small is better.
    However, stationary power plants are well, what is the right word, stationary.
    There are many small stationary power plants in the US. None of them are nukes today. They are fuel by natural gas, coal, biomass, and waste. Part of any marketing plant is to be objective about the completion.

  4. I’m trying to get a handle on how it was that big nuke plants were constructed pre TMI at attractive prices but then kablooey, the US new nuke building industry dies. Before the US lost its nerve about nuclear, big plants were what they built. The fact that some plants were built pre 1980 for $500 per kw, that ended up successfully getting extended operating licenses totaling 60 years so far says a lot about how cheap and fast things could be done right once again.
    I like to imagine that one day the entire society will be galvanized in a way it was after 9/11 or Pearl Harbor, over the threat only massive new nuclear can realistically solve, i.e. climate change.
    At that time, it will be unpatriotic to blow radiation hazards out of proportion in the way the tritium leaks at Vermont Yankee just were. I imagine people will be unified in a desire to make the nuclear industry succeed, as opposed to now when a lunatic fringe has succeeded in forcing any number of actions that are aimed at forcing the industry to fail.
    A small reactor design seems to me to be a response to this insane environment of today where this perfectly good nuclear technology has been vilified and repressed while the fossil fuel industry blithely goes about destroying the life support capacity of the entire planet.
    I took a look at a “big” plant, the Columbia Generating Station in Washington State, and I wished there were 1,000 of those powering the US right now. A load of 100MW plants means there would have to be 10,000 of them. When they start considering how to refit the entire US electricity supply by scrapping all fossil fuel plants no matter how new they are because people have suddenly realized how dangerous CO2 emissions are, will they settle on a design that has to be replicated 10,000 times, or will 1,000 reactors look more appealing?
    Obviously, I live in a fantasy world.
    I support the “science projects” if only as a solution to the “waste” problem. I’d put the funds collected so far part of which were wasted at Yucca into a fast reactor program aimed at working out the bugs so enough fast reactors could be made to burn all the waste of a fleet of reactors generating all energy required in the US.

    1. All we can do is try to educate. Nuclear will be embraced by the general public once the general public needs it or the general public understands it and, thus, accepts it. (That time comes, at least in terms of need.)
      I think that small reactors, especially ones capable of generating very high temperatures, will be viable even in a theoretically unrestricted environment. Electricity, for all its uses, is a very inefficient means of heat transfer, and more direct heat sources will still be preferred by end users even if electricity is “too cheap to meter”.
      Small also has reliability/redundancy, agility/responsiveness, efficiency (by locating the small reactor closer to the end user, there is less energy lost), and scalability pulling for it, while large has economy of scale, long life, and horizontal integration pulling for it. I think that both types of plants will find their market in the future of nuclear energy – just as fossil fuels are used today in applications from baseload all the way to home furnaces (well, a household boiler being nuclear fired might be a little far-fetched…but…what else are we going to do with the Pu-238?)

      1. Even if I totally support (small) nuclear reactors district heating (and cooling), it’s not true that “Electricity is a very inefficient means of heat transfer” if it’ s used to power efficient heat pumps, indeed *at least* double the efficiency can be obtained if we’d switch from boilers to electric heat pumps – besides the fact that electricity can be distribuited for very long dstance with little losses while hot water can’ t

    2. David
      The first thing that happened was that demand growth was overestimated. About 1/3rd of nuke plants that were canceled before TMI.
      The second thing that happened was double digit inflation along with construction delays because of TMI.
      Then there were the inept. WPPSS tried to build 5 large nukes at the same time with no large power plant construction experience.
      Finally, good project management increased the productivity of nukes. We did not need new nukes because of better performance of existing nukes.
      All that is needed to build new nukes is good project management that instill confidence with investors.

    3. David,
      I realize I represent a minority view here which, for various reasons I find odd but I “go with the flow” because I believe nuclear power just plain makes sense from a density of resources standpoint. My minority view is that climate change will not develop into the 9/11 or Pearl Harbor-type threat that some think (even hope) it will take to shift from carbon-based energy sources – either transportation fuels or electricity generation.
      I am not persuaded by alarmism, particularly when the result would leave millions (even billions) of people to suffer in abject, brutal poverty while advanced societies and nations wring their guilt-ridden hands over releasing CO2 (all the while comfortably tapping away on their computer in climate-controlled homes, offices and coffee houses). Elite-ism, either in social sciences or politics or even the “hard” sciences, is unseemly. The drubbing of the UN IPCC and affiliated organizations, groups and individuals is a cleansing long overdue, IMHO, and will result in far better policies of resource use.
      I thought the B&W interview was refreshing in its recognition of their strengths and the realities of the process they are obliged to follow. Rather than waste energy fighting for “transformative” processes, they are wisely working the path that will bring their technology to market the fastest. Being “vanilla” instead of some exotic new taste makes their offering more appealing and acceptable to the current gate-keepers.

      1. Doc – I do not think that you represent a minority viewpoint, but the main point is that nuclear has tremendous advantages over the competition even if you discount the possibility that greenhouse gases are a threat. Do you also discount the damage done by all of the other junk that pours out of a fossil fuel stack?
        Please understand my position. IF there was no fission alternative, I would perhaps be willing to take the chance that we could burn up all of the fossil fuel on the earth without causing a major change in the world’s climate. Doing without power is more dangerous.
        However, there is an alternative that is better, more abundant and cleaner than burning fossil fuel in many applications. Why should I avoid helping people to understand that this source is worth considering even if the only reason they are interested is do to the well publicized risk of catastrophic climate change. Perhaps the risk is a bit over stated, but are we really sure? Is the “science settled” that it is NOT a potential threat? Should we really do the experiment when we do not have to?

        1. @Rod — I fully agree that nuclear power represents a significant improvement in energy generation over all other forms and by orders of magnitude. As a Boy Scout, as a grandson of mid-west farmers and simply as one who promotes good stewardship of our resources, I am repulsed by all forms of pollution – including verbal, particularly in public venues. So please don’t take my position as supportive of unregulated coal, oil or gas production.
          Whenever I read articles on energy, I routinely voice strong support for nuclear power and reference this blog, among a select few others, as I respect the quality and approach taken. So, despite my lack of specific knowledge within the nuclear industry, I am a vocal cheerleader precisely because of what I’ve learned here and from others on your blogroll.
          The issue of climate change will sort itself out in due time. I am reminded of the effect of alarmism by your recent post on tritium: how a penny is compared to $10 Billion vs pico-curies. Can that same argument be waged in comparing 0.04% atmospheric CO2 and the tons of CO2 added annually? Certainly there is an upper limit to what is acceptably safe, but does anyone know where that “limit” is?
          As always, keep up the good work at informing all of us, whether we are in full agreement or not.

  5. The mPower appears to represent a revolutionarily evolutionary design, a thoroughly engineered advance on the light water state of the art that isn’t a “science project” and can be easily deployed. (A word about “science projects” – they should still be fully conducted – merely because Generation IV isn’t ready today doesn’t mean that Generation IV should or even CAN be ignored.) The mPower’s lack of chemical shim, the entirely integral primary – allowing credible LOCAs to be avoided, the integral recirculation pumps, the “core plug and play” option combined with 5-year refueling cycles, the below grade containment, the use of a dry cooling system, the omission of a pressurizer, the use of superheat to avoid saturated steam, etc, all point to this being a credible option for those wanting a simple nuclear plant that “just works”, such as smaller utilities, while larger utilities wanting a larger option could build “reactor parks” full of these underground modules. I suppose that when one buys in bulk, the price drops.
    As such, I can see that the mPower has a bright future ahead of it – for the simple fact that it appears to be thoroughly engineered, probably comes with a fixed price tag, is of a credible size that is neither too small or too large (125 MWe), is very safe, is built to avoid problems with the NRC, and is quickly deployable on a reasonably large scale.

  6. Boy, I’ve been starving for more details about the mpower reactor concept. Thanks for the link!

    1. Robert,
      The Mpower is a conventional pressurized light water reactor.
      Other than its small size, one the thing that really sets it apart is having the steam generator and pressurizer in the same pressure vessel. This means, among other things, that there are no large external plumbing connections on the primary coolant loop.
      A second think that sets it apart is, if the reactor is shut down or scrammed, active pumping is not required for cooling. The reactor can be adequately cooled by convection. From a cost standpoint, this gets the coolant pumps out of being primary safety equipment.
      OBTW, the published 125 MW rating is with air cooling on the secondary side. If it is water cooled like most of the other PWRs, it is rated at 140 MW.

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