Thursday, June 3, 2021

New Nuclear Power?

I've had a fascination with nuclear power for about 40 years. As a teenager, I watched the construction progress of a small nuclear power plant about 20 minutes from home; that reactor, built in the 1970s, has since been shut down after several extensions of its license by the Nuclear Regulatory Commission (NRC). Normal licenses are for a 25-year lifespan, but because of the safety record and design of this particular plant, they were able to get it extended until 2033. The flooding of 2011 showed that it was in a poor location (it had been shut down for refueling before the flood and was in no danger) and the operator decided to cease operations in 2016. Cleanup and decommissioning is still going on, and the old fuel rods are stored on-site so it will be a secured area for a long time.

Having grown up in the shadow of a nuclear power plant, we dealt with a lot of emergency planning and notification information coming from the operator of the plant, FEMA, and the Nuclear Regulatory Commission (NRC). A network of warning sirens was placed about 15 miles in every direction around the plant. Testing every month became just another part of life, kind of like the Emergency Alert System tests on the radio. Our house was far enough away that we were not in any of the emergency zones, but we still got an annual map of evacuation routes. Growing up during the Cold War, a lot of what we now call prepping was just everyday life back then.

All of this came to mind this week because of the announcement that the founder of Microsoft is funding a company that wants to build a new nuclear power plant in Wyoming. This is notable because the newest nuclear plant we have in the US was commissioned in 2016, and the second newest is 20 years older than that. Construction of conventional nuclear plants has been rare and slow for a generation because of an attitude whereby people want electricity, and agree that nuclear power is the cleanest source, but don't want a plant built near them -- aka Not In My Back Yard (NIMBY). Lawfare from various environmental groups has also slowed or stopped the construction of pretty much anything nuclear. We'll see if huge piles of money can make a difference this time.

Pressurized Water Reactors
Nuclear power plants, if built by good workers and designed by competent engineers are as safe as a coal-fired plant and don't produce as many by-products. If you happen to live near one, learn as much as you can about it from reliable sources and pay attention to the NRC-required informational packets. They aren't nuclear bombs waiting to go off; instead, the major threat is a steam explosion or release of radioactive materials. Erin and I have covered the basics of radioactivity in the past.

This new reactor, however, is of a new design. The older nuclear reactors used a (barely) sub-critical mass of Uranium to heat water under pressure (superheating)*, transferred heat from that very hot water to a secondary system at lower pressure where it would create steam that could spin a turbine connected to a generator. Called a “light-water reactor” (LWR) or Pressurized Water Reactor (PWR), this has been the only design approved for power generation since the 1950s in the USA. (Other countries have other designs, and they don't always have the same safety record.) LWRs have the major problem of containing the superheated water, which leads to huge containment vessels and redundant pumps, adding to the cost of construction and operation.

* Just like water will boil at less than 100°C/212°F on a mountain top where the air pressure is low, you can keep it from boiling and changing to steam (which takes up 17,000 times more space than the liquid) by increasing the pressure. If you're interested in the exact numbers, look up “steam tables” for boiler operations.

Liquid Sodium Reactors
This new design is called a Natrium or Liquid Sodium Reactor (LSR). Selected by our Department of Energy (DOE) as a promising technology, it has been funded and tested extensively in the last decade or so. Instead of super-heating water, the Natrium system uses the heat from a nuclear reaction to melt a giant tank of salt. That liquid salt is at a much higher temperature than you can reasonably get water, and it doesn't require the high pressures that super-heating water does, which leads to a safer and simpler construction. That heat is used to create steam and drive a turbine like any other generation station. 

Molten salt is a bit corrosive, so they've been researching materials that are safe to use. Natrium uses a modular approach to their design, making power plants more flexible in their output. The liquid salt can also be used to store heat (several solar-thermal systems use it as a “heat battery”) for boosting generating capacity when needed instead of relying on natural gas-fired peaking generators.

The nuclear side of the reactor will still work the same and will still have some of the same issues. We don't yet have a good way or place to store spent fuel rods, so they'll be a sore spot. Reprocessing those rods tends to generate Plutonium (Pu), and our current needs for that have already been met. Certain groups get very vocal when you start talking about stockpiling the makings of nuclear weapons, so Pu is a no-no.

We'll have to wait and see what happens with this project. The design is much safer than a LWR, but the current political and social atmosphere is not friendly to new sources of energy, and pipelines, new oil well drilling permits, and new refineries are all on hold or canceled. Building anything will take years to get all of the permits and settle all of the lawsuits, but we need to have something making the electricity for all of those new electric vehicles that are being sold.


  1. I disagree with you completely. Nuclear power plants are not safe. Chernobyl, 3 mile island, Fukushima. Saying you can build it safer our way is like saying socialism will work if you do it my way.

    1. Comparing nuclear reactors to political systems is worse than apples and oranges. Throw a capitalist, a communist, and a libertarian out of a helicopter and they're all going to hit the ground. Basic physics doesn't care about political leanings.

      Chernobyl was a bad design and had various safeties disabled. 3 Mile Island was similar. Fukushima was an act of nature. Compare the deaths from mining accident to how many died in all of the reactor accidents in the same time period. Now add in the increases in cancer and disease from the contaminants in coal and oil. Nuclear energy is as safe as humanly possible. Nothing is perfect, but using fission to boil water is just as safe as using oil, gas, or coal.

    2. And there you go. As long as you build it my way, it's safe. Who is to say another act of nature won't come along, more safeties disabled. The long term effect of nuclear are much worse than anything coal can do. How long before chernobyl can be reused. Nuclear fission may be safe to boil water. Until it's not.

  2. An academic reactor or reactor plant almost always has the following basic characteristics: (1) It is simple. (2) It is small. (3) It is cheap. (4) It is light. (5) It can be built very quickly. (6) It is very flexible in purpose. (7) Very little development will be required. It will use off-the-shelf components. {8} The reactor is in the study phase. It is not being built now.

    On the other hand a practical reactor can be distinguished by the following characteristics: (1) It is being built now. (2) It is behind schedule. (3) It requires an immense amount of development on apparently trivial items. (4) It is very expensive. (5) It takes a long time to build because of its engineering development problems. (6) It is large. (7) It is heavy. {8} It is complicated.

    The tools of the academic designer are a piece of paper and a pencil with an eraser. If a mistake is made, it can always be erased and changed. If the practical-reactor designer errs, he wears the mistake around his neck.

    —Admiral Hyman G. Rickover, Paper Reactors, Real Reactors, 1953


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