May 26, 2015

Ultra-modular Thorium Molten Salt Shipping Container Reactors

The following is a concept based on current and past pursuits in small reactor technology. Today, there are two major issues we need to solve. 1- We need to build a global, free, open internet for all mankind to use. I am working on this problem today, and it is easily feasible (Mostly through software). The next leap will require slightly more resources: 2- Energy. Global fossil fuels consumption is accelerating rapidly, with higher energy demands each year. Here's how we get our power (Courtesy of the EPA):
Over 80% of our energy comes from burning the ancient forests of our Earth. This simply isn't sustainable. Much like our demand for internet, our demand for energy is insatiable. In order for us to keep up with increasing demand we need new sources. Fusion is still at least 20 years away, we need a solution for now. But in order for nuclear to work, it must be at the right price and in the right form factor. To look at the future we must look towards the past:

As our nation came out of WWII, atomic energy was applied to a wide variety of tasks. WWII was won partially because of our oil infrastructure, and the Army wanted the best energy sources for any future conflict. In 1954 the Army officially began it's nuclear power program. Over the course of its operation, reactors were built in Antarctica, and along the Dew Line. One reactor even powered an underground ice base at Camp Century, Greenland. 
One variation was the highly experimental reactor shown above. It consisted of six shipping container-sized modules, to save weight, radiation shielding was removed. The main control module required placement 500 feet away from the reactor unit. The Nitrogen-cooled gas-turbine design was fraught with technical problems and corrosion issues.  Deemed a failure, it was an important experiment in portable reactors. 
The Air Force experimented with nuclear powered aircraft (ARE) in the 1950's, creating the foundations of molten salt reactor design. Oak Ridge National Laboratory furthered such experiments  with a highly successful test ending in 1969. Research began to fizzle out as funding dried up in the 1970s and 80s.
The Navy now leads the Nuclear era with their small, modular, pressurized water reactors (SMRs). Such reactor designs have been powering submarines for over 60 years. They now operate a fleet of over 80 subs and carriers (as of 2014) powered by SMRs, many of these vehicles carry more than one reactor.  This IRIS reactor operates on similar principles and is designed mainly by Westinghouse, the maker of many Navy reactors:
Some very interesting research is going into the creation of combustion fuel from seawater using such reactors. Though the Navy has much more advanced reactors, this SMR technology is beginning to hit consumer markets. 
The problem with small uranium reactors is their cost, mainly because of their unsafe inherent safety profile and setup costs. Simon Irish gave an insightful talk on how increased safety directly reduces the cost of building and running nuclear reactors. While SMRs are an order of magnitude safer than the outdated goliaths used in Chernobyl and Fukushima, uranium still poses hefty proliferation and regulatory concerns. 
The only way to build and operate SMRs affordably are to make them:
  1. Inherently Safe
  2. Modular
  3. Autonomous
  4. Portable
  5. Low Proliferation Risk
  6. Efficient
  7. Mass Produced 
The only way to drive down the cost of nuclear power is to mass produce small units. Using the much safer, liquid fuel cycle will also drastically improve safety and efficiency. ML-1 got a lot of things right. It was very cheap to set up (compared to today's custom, >$1bn power stations). Technological and theoretical advancements would now allow a portable, ML-1-like unit to be quite viable. I suspect many such units likely exist in our current "Arsenal of Democracy". The government builds cool stuff, much of which we will never get to see.
Because the military and commercial world operate in very different regulatory environments, running a uranium reactor is too expensive to be viable for small, cheap units. Our next option, one that is in it's early stages of development is Thorium. I believe it's going to take the following configuration for nuclear to truly have a positive global impact: I call it BLOKenergy
The primary reactor fits in one 40 foot ISO shipping container. Its molten salt rector is highly modular, mass produced, and inherently safe. If any problem occurs, the molten reactor is drained, and the nuclear reaction ceases. Here's what the inside might look like:
The primary reactor consists of two "containers". The reactor, heat exchangers, and steam generator consist of the first module. The second reactor module consists of fuel re-processing equipment (Much of which is highly experimental and the primary object of research in Thorium reactors)
Many modern designs are utilizing a gas-turbine technology to convert heat into electricity. While more efficient (nearing 50%),  this technology is also quite young and expensive to build. To keep the first iteration simple, I opted for steam, as these units can be deployed to heat homes, or integrate with current small scale coal and gas electrical generation. One module can work without the other (Except the two reactor modules), allowing for a highly configurable energy source. All of this is controlled via onsite computers and through an encrypted satellite connection.
The steam generators will input steam directly to the turbine module, housing generators and steam turbine equipment. Production would begin first on steam turbine units, as these can be sold (regardless of any reactor) to be used in current coal and gas power generating configurations. These types of steam generators are in production and have been in use for over a hundred years.
Another helpful module would be the desalination unit. Multiple Effect Distillation, or Multi-stage flash distillation (The latter being more efficient at high temperatures, the former is better using waste heat from steam turbines) would be used to turn Sea water into fresh water. California is in a heavy drought, which to me is silly as we are along an ocean. We just haven't found an economical way to get the salt out- Yet.
Today the possibilities for nuclear are endless, with fusion assuredly on the horizon. Our demand for oil is only increasing and nuclear is currently the only truly sustainable option. While wind and solar are great, they can't yet provide the amounts of continuous energy we need, especially for industrial applications. Our future energy infrastructure should include a healthy mix of wind, solar, and nuclear.
Future iterations will likely include a gas turbine design, allowing for higher efficiency and heat distribution for industrial applications.  Many (petro)chemical manufacturing processes require high heat (eg ammonia production), that molten salt reactors could provide economically.
Much of what I write about is very possible today. A major factor holding thorium back is the fuel supply chain. Currently China controls much of the world's thorium, as it is a byproduct of rare-earth mining. India has also added thorium to its three stage nuclear program. Thorium is plentiful in most parts of the world (especially the US, India, and Australia). The problem is much of it is extracted through rare earth mining, in which the US is woefully behind the rest of the world, with China taking the lead. Considering the state of affairs, China will likely pioneer the commercialization of thorium power, as they currently have a lot of thorium sitting around. Here's a USGS map of Th in the US:
The last problem is economics. The current demand to develop radical new technology in this country is relatively low. I believe it will take about 8 years for this technology to be ready for prime time, and when it does- its going to have a global impact. With current thorium reserves we can end drought, bring electricity and warmth to the furthest stretches of our planet, all with minimal environmental impact. This modularized approach just might be what it takes to wean off our oil addiction until we can get fusion to work.
Until then,
Garrett Kinsman  ::  May 25, 2015

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