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Atomic Insights

Atomic energy technology, politics, and perceptions from a nuclear energy insider who served as a US nuclear submarine engineer officer

Adams Engines

Adams Engines™: Design Concepts

December 18, 2020 By Rod Adams 17 Comments

In the spring of 1991, I began contemplating ways to combine the benefits of gas turbine power plants with the incredible advantages of nuclear fuels like uranium, plutonium and thorium.

That effort has continued sporadically for many years with many interesting impacts on my life. It was impetus for a small modular reactor start-up company that never gained sufficient traction. It has led to many fascinating conversations and more than a few close friendships.

I thought it would be worthwhile to share an updated version of a concept paper first published on the Adams Atomic Engines, Inc. web site in 1995.

There are numerous reasons for making this document readily available. I hope that some of you will take the opportunity to ask questions and make comments.

Filed Under: Adams Engines

Turning nuclear into a fuel dominated business

October 28, 2018 By Rod Adams 66 Comments

Cross section of TRISO fuel particle
TRISO particle – 1 mm diameter

Under our current energy paradigm, nuclear power has the reputation of needing enormous up-front capital investments. Once those investments have been made and the plants are complete, the payoff is that they have low recurring fuel costs.

Just the opposite is said of simple cycle natural gas fired combustion turbines. They require a small capital investment that can be paid off even if the plant only operates a few hundred hours per year. They don’t have an optimized fuel efficiency and they burn a fuel that can be quite expensive during the hours when the “peakers” need to run.

Those peakers are responsive and are becoming more interesting to power producers with the continued growth In variable renewable energy sources like wind and solar.

Just thinking out loud here, but what if it was possible to build really simple, much lower cost nuclear plants on the condition that they have a safety case that is built around a fuel design that is several times more pricey than conventional commercial nuclear fuel?

For more than 50 years, scientists and engineers have been working on coated particle fuels where tiny particles of fissile material in various chemical forms is surrounded by tightly adherent and durable layers of material capable of withstanding very high temperatures without releasing fission products.

In the space program, incredibly powerful and energy dense reactors have been designed and tested using coated particle fuels, but for commercial power generation, the usual path is to create large low power density reactors that are considered to be “inherently safe” because they don’t need any active cooling systems to prevent the core temperatures from exceeding the much more generous limits allowed by high temperature fuel.

Unfortunately, the development of reactors using coated particle fuels has been held back by a couple of technical choices. One has been that the reactors have been seen as a modest improvement in conventional reactors that still need to have most of the expensive equipment of a steam plant power conversion system.

Using that heat engine choice, designers must include heat exchangers that are functionally equivalent to the high cost steam generators in pressurized water reactors. Since they need heat exchangers, they naturally look toward high gas pressures in the primary coolant loop in order to increase heat transfer rates.

That path leads to systems with capital costs that are not much different from conventional nuclear plants with the added burden of using fuel that is quite a bit more expensive, especially in the early years before the manufacturing lines become cost efficient.

General Atomics achieved initial marketing success with a line of GW class high temperature reactors (HTRs) in the late 1960s and early 1970s by emphasizing that their systems were somewhat simpler and used more conventional steam turbines than the lower temperature light water reactors. They inked about 10 contracts, but none of the plants were ever built.

X-energy, URENCO and HTR-PM all are pursuing updated versions of similar designs. They are not radically reconsidering the paradigm.

It’s possible to dig back into nuclear history and find that the HTRE (high temperature reactor experiment) used modified jet engines that sucked in atmospheric air, heated it in a modestly high temperature reactor (far lower temps than coated particle fuels enable today) and exhausted that air through a turbine and jet expansion system.

The capital cost of equipment for such an air breathing system today would be quite low, but there would likely be a problem with creating and emitting Ar-41 as well as the possibility that fuel manufacturing defects might allow some small quantity of fission products to be discharged. Regulatory hurdles prevent that path from being developed anytime soon.

With a modest increase in complexity and capital equipment, a mechanically identical system could use nitrogen gas separated from air. Because the gas isn’t air, it would need a closed system where a low pressure, moderate temperature heat exchanger performs the function of returning turbine exhaust back to atmospheric conditions for injection into the compressor.

This ultimately simple Brayton Cycle gas turbine would use fuel that might cost several times more per unit of heavy metal than conventional nuclear plants, but its initial investment should approach the cost of the combustion turbines that would be the heart of the system. Sure, there are costs associated with the piping systems, but those would likely be on a similar order of magnitude as the fossil fuel system pipes that would not be needed.

With dramatically lower capital costs and higher fuel costs, the total system cost allotment would be a complete departure from the conventional nuclear paradigm. No longer would equipment suppliers and financial providers be able to capture 50-75% of the total revenues, with personnel costs capturing 30-40% and the fuel supplier pulling up the rear with 5-20% of the revenue. Instead, financial costs could be far lower. Equipment costs would drop dramatically. Personnel costs per unit of output would fall.

The obvious result is that the fuel suppliers, the people who produce the fuel that is so capable that it is the safety case and safety boundary, would gain the lion’s share of revenue from product sales.

That situation has proven itself in the energy market. Customers and other stakeholders don’t necessarily like the fact that fuels people walk off with most of the money, but it has meant that fuel suppliers have adequate capital to both invest in new technologies and adequate incentives to promote the benefits of high energy use.

There is a massive amount of capital in the hydrocarbon fuel business. There is also a great deal of intellectual capital, some of which is scientific and technical, but some of which is business development and marketing.

In the early days of nuclear energy, the hydrocarbon giants dipped their toes in the business. They couldn’t figure out how to make as much money in nuclear as they were used to making, so they quickly exited.

Perhaps this early Sunday morning essay will help stimulate them to reconsider their decision to abandon the business without figuring out how to make it a fuels business that could answer a lot of their future challenges.

Note: I have more details about the paradigm shift described above, but I think I’ll hold them closely for now.

Filed Under: Adams Engines, Advanced Atomic Technologies, Business of atomic energy, Economics, Gas Cooled Reactors, Graphite Moderated Reactors, Pebble Bed Reactors, Smaller reactors

Diamond batteries would turn C-14 into a valuable byproduct of Adams Engines

December 5, 2016 By Rod Adams

Researchers at the University of Bristol have excited geeks around the world by announcing they had successfully demonstrated artificial diamonds that produce an electrical current when exposed to radiation. Their research has been inspired by a fact that is almost unique to the UK. There is a large stockpile of radioactive carbon-14 available as a […]

Filed Under: Advanced Atomic Technologies, Adams Engines

Innovative closed cycle gas cooled reactor – circa April 1956

January 3, 2016 By Rod Adams 44 Comments

I came across an advertisement in the April 1956 issue of Scientific American that I simply had to share. Does anyone recognize the basic concept described by the Ford Instrument Company (a division of Sperry Rand Corporation) almost exactly 60 years ago?

Filed Under: Adams Engines, Advanced Atomic Technologies, Atomic history

Using portable nuclear generators to break petroleum logistical dependence circa 1963

October 27, 2015 By Rod Adams

Note: The initial version of this post was written based on an incorrect interpretation of the Roman numeral date stamp at the end of the video. The film was made in 1963, not 1968. The post was revised after a commenter provided the correct production date. End note. I have a theory about why the […]

Filed Under: Adams Engines, Advanced Atomic Technologies, Atomic Entrepreneurs, Gas Cooled Reactors, Pebble Bed Reactors, Small Nuclear Power Plants, Smaller reactors

Fission is an elegant way to heat a gas

June 26, 2014 By Rod Adams

What if it was possible to combine the low capital cost, reliability, and responsive operations of simple cycle combustion gas turbines with the low fuel cost and zero-emission capability of an actinide (uranium, thorium, or plutonium) fuel source? Machines like that could disrupt a few business models while giving the world’s economy a powerful new […]

Filed Under: Adams Engines, Advanced Atomic Technologies, Gas Cooled Reactors, Graphite Moderated Reactors, Pebble Bed Reactors, Small Nuclear Power Plants, Smaller reactors

NGNP aims to expand nuclear fission out of its electricity producing niche (box)

March 7, 2013 By Rod Adams

Enterprise and Escorts Demonstrate Nuclear Propulsion

The NGNP Alliance recently published a thought provoking blog titled Energy Vs. Electricity and Why We Care that clearly explains the basis for their interest in using high temperature gas cooled reactors. That group of far-sighted organizations was formed in recognition that the energy market is far larger than just producing electricity. They believe that […]

Filed Under: Adams Engines, Gas Cooled Reactors, Graphite Moderated Reactors, Small Nuclear Power Plants

Atomicrod visits Dot Net Rocks to chat with Carl and Richard

February 8, 2013 By Rod Adams

On January 18, I joined Carl and Richard, the hosts of Dot Net Rocks, for an hour long conversation about nuclear energy. We spanned a number of topics including current light water reactors, breeder reactors, accidents, safety records, SL-1, NR-1, Mars Rover, pebble beds, IFR, and traveling wave reactors. Please go visit and listen.

Filed Under: Adams Engines, Ask Atomic, Nuclear Communications, Smaller reactors

Adams Engine – Goal is cheap, ultra low emission fuel coupled to cheap machinery

January 31, 2013 By Rod Adams

Though I am not actively pursuing the idea right now, I have had several opportunities in the past couple of days to explain to people why I made the design decisions I did when putting together the Adams Engine concept. As a rather lazy man, I figured it would be easier to repurpose those arguments […]

Filed Under: Adams Engines, Advanced Atomic Technologies, Economics, Smaller reactors

The Atomic Show #132 – Ray Squirrel Interviews (Atomic) Rod Adams

May 17, 2009 By Rod Adams 10 Comments

Ray Squirrel is the screen name used by a documentary film maker who is collecting material for a film about nuclear power. You can find some of the work he has done so far at RaySquirrel’s youtube site. I am not sure how the film will come out, but I thought you might be interested […]

Filed Under: Adams Engines, Alternative energy, Atomic Entrepreneurs, Atomic politics, Podcast Tagged With: Adams Atomic Engines, atomic, Atomic engines, Chernobyl, natural gas, solar, TMI, wind

The Atomic Show #129 – Atomic Gas Turbines

April 1, 2009 By Rod Adams 3 Comments

On March 30, 2009, I had the privilege of presenting a talk at my alma mater on the topic of nuclear heated Brayton cycle machines – also known as atomic gas turbines or Adams EnginesTM. This episode of The Atomic Show is my first attempt at an enhanced podcast using chapter markers and trying to […]

Filed Under: Adams Engines, Alternative energy, Atomic Entrepreneurs, Podcast Tagged With: Adams Engines, Atomic gas turbines, high temperature gas reactors, HTR-10, inherently safe, N2 coolant, PBMR

The Atomic Show #099 – StartupStoryRadio.com interviews Rod Adams of Adams Atomic Engines, Inc.

July 27, 2008 By Rod Adams 1 Comment

Rob McNealy is the host and producer of StartupStoryRadio.com. Rob and Rod Adams chatted recently about Rod’s efforts as atomic entrepreneur who wants to change the world. Rob McNealy of StartupStoryRadio.com and I had an interesting chat on Tuesday about Adams Atomic Engines, Inc. (AAE). We discussed the 15-year effort to build an independent, atomic […]

Filed Under: Adams Engines, Podcast, Smaller reactors Tagged With: atomic, nuclear entrepreneur

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