• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Home
  • About
  • Podcast
  • Archives

Atomic Insights

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

Pebble Bed Reactors

China’s high temperature reactor – pebble bed modular (HTR-PM) achieves its first criticality

September 14, 2021 By Rod Adams 34 Comments

On the morning of September 12, 2021, reactor number 1 of the eagerly awaited HTR-PM project was taken critical for the first time. Initial criticality for any new reactor is a big deal for the people involved in the project; this one is a big deal for the future of nuclear energy. It might also become a big deal for humanity’s ability to effectively reduce CO2 emissions enough to slow climate change.

HTR-PM is a demonstration reactor that uses two identical gas-cooled high temperature modular reactors to produce the heat for a modern, subcritical, 200 MWe steam turbine. The steam system operates at the same temperature and pressure as many recently constructed coal heated steam plants that China has been mass producing for more than a decade as it rapidly industrialized and became one of the world’s leaders in manufacturing, metals production and chemicals.

The press release from China National Nuclear Corporation (CNNC) includes the following statement.

They [HTRs) have broad commercial application prospects in nuclear power generation, combined heat, power and cooling, and high-temperature process heat. They are my country’s optimization of energy structure and guarantee of energy supply. An important path to safety and to achieve the “dual carbon” goal.

China National Nuclear Corporation press release dated 09-13-21 (https://www.cnnc.com.cn/cnnc/xwzx65/ttyw01/1112318/index.html) Note: Original in Chinese simplified, translated by Google Translate

Though the announcement does not specifically include coal furnace replacement, producing steam at the same temperature and pressure as used by modern coal plants qualifies as “high-temperature process heat.”

HTR-PM criticality is the most recent step in a long process of commercializing high temperature gas cooled reactors. Though they have a long history, proponents (like me) believe they are an advanced type of commercial atomic fission power technology. (See the high temperature gas reactor history description below.)

China has been purposefully working on high temperature gas reactor technology development for the past 30 years. They have absorbed lessons from HTR experience in Japan, the United States, the UK, and South Africa while also building their own domestic intellectual property and manufacturing capability. According to the China Huangeng Group Co. LTD (CHGC) press release, the project’s direction includes a strong emphasis on building indigenous capacity to build HTR without outside assistance.

As the world’s first pebble-bed modular high-temperature gas-cooled reactor, the demonstration project used more than 2,000 sets of equipment for the first time, and more than 600 sets of innovative equipment, including the world’s first high-temperature gas-cooled reactor spiral-coil once-through steam generator. The first high-power, high-temperature thermal magnetic bearing structure main helium fan, the world’s largest and heaviest reactor pressure vessel, etc., are of great significance to promote my country to seize the world’s leading advantage in the fourth-generation advanced nuclear energy technology.

China Huangeng Group Co. LTD press release dated 09/12/21 (https://www.chng.com.cn/detail_jtyw/-/article/ccgb60va5Gwc/v/962479.html) Note: Original in Chinese simplified, translated by Google Translate

Aside: The above includes a statement that helps explain why HTRs have not been universally popular and why they still face headwinds, even from nuclear energy advocates. Each reactor module produces about 250 MWth, which compares to about 3300 MWth in a 1000 MWe PWR or BWR. Even with higher temperatures and higher efficiency, each core can produce 1/10th of the electricity of light water reactors, but the first HTR pressure vessel is described as “the world’s largest and heaviest pressure vessel.” Pressurized gas has a far lower capacity to move heat than pressurized water.

But there are more factors to be considered in atomic fission power plant economics than the size and weight of the pressure vessel. End Aside.

China is rightfully proud of its accomplishment in achieving HTR-PM initial criticality. There are many more steps in the journey, but this step is important. It marks one more milestone in the process of creating nuclear fission power stations that can take full advantage of the world’s vast coal fired power station infrastructure.

Brief high temperature reactor history

Arguably, the basic idea for HTRs was initially proposed during the earliest days of nuclear power development – immediately following WWII. Dr. Farrington Daniels proposed a high temperature gas reactor as the heat source for what was then a modern steam system. The Daniels Pile project was initially funded by the Manhattan Commission and gathered some momentum before being abruptly cancelled by the nascent Atomic Energy Commission in early 1947.

In the late 1950s Germany’s Rudolf Schulten followed through on the idea and led the project to build the world’f first high temperature pebble bed reactor, the AVR. That small (46 MWth, 15 MWe) prototype operated for about 20 years. Its construction began in 1960, it was connected to the grid in 1967 and it was shut down in 1988.

The US and the UK built their own version of high temperature reactor prototypes, the US at Peach Bottom and the UK’s Dragon reactor at Winfrith in Dorset.

General Atomics, the US company that designed and built the successful prototype at Peach Bottom built a scaled up, significantly different design at Ft. St. Vrain (330 MWe). That reactor had a dismal operating history due to several FOAK system design problems. By the time the defects were corrected, the designer had lost all of the follow on orders. The plant owners had lost patience, didn’t want to own and operate an orphan plant design and shut the system down.

Germany built a larger, 300 MWe pebble bed reactor (THTR) but that reactor had unfortunate timing. It began operating in 1985 with a 1000 day temporary operating license. Before THTR had operated long enough to complete testing and rise to full power operation, the Chernobyl reactor exploded. Reports claimed that the graphite moderator was a primary contributor to the accident and there was a widespread, durable misinterpretation that the graphite actually caught fire.

THTR was a graphite moderated reactor. Owners could not convince the public or the regulators that there are fundamental differences between graphite moderated, helium cooled reactors and graphite moderated, water cooled reactors. THTR was shut down in September 1989 when its initial license expired and that license was not extended.

In the 1990s, South Africa invested several billion dollars and a lot of engineering effort in developing the pebble bed modular reactor (PBMR). A primary reason that effort did not achieve success is that it started with the notion that it was reasonable to build a 200 MWe turbine generator with high pressure helium as the working fluid and then to mount that large machine vertically inside a pressure vessel. That concept works on paper, but executing it proved to be extremely difficult and expensive. Before the project ended, designers had decided to mount the helium turbomachine in a more conventional, horizontal alignment, but the South African government had lost patience by that time.

Chinese technologists, led by Prof. Zhang Zuoyi, learned from PBMR’s experience. They chose to step back to what had worked well for the AVR and to gradually make improvements. They built the HTR-10, a 10 MWe prototype system with a helium to water steam generator that helped them learn on an affordable scale while planning for the next iteration.

HTR-10 has operated well as a prototype. Its capacity factor has been modest, but it wasn’t conceived as a steady state, commercial electricity producer. It has been used to test fuels, test materials, test equipment, train operators and refine operating procedures. In other words, it has done what prototypes are supposed to do.

Construction on HTR-PM began in 2012. It has taken a bit longer than initially planned, but part of the delay rests with the fact that some of the necessary components – like the unique, spiral-coil once-through steam generator – were difficult to design and refine into something that could be efficiently replicated.

The Shidaowan site is planned to eventually host 16 more HTR-PMs. There are already plans underway to design and build an HTR-PM600. That system will use pebble bed reactor models – each the same as the reactor modules used for the HTR-PM) to provide the required heat for a 600 MWe steam turbine power station.

Filed Under: Advanced Atomic Technologies, Atomic history, Business of atomic energy, Gas Cooled Reactors, Graphite Moderated Reactors, International nuclear, New Nuclear, Pebble Bed Reactors, Small Nuclear Power Plants, Smaller reactors

Atomic Show #288 – Per Peterson, CNO, Kairos Power

January 25, 2021 By Rod Adams 9 Comments

Per Peterson in R-Lab with ETUDE, the scaled water test version of the Engineering Test Unit now in construction in Albuquerque
Image provided by Kairos Power

Kairos Power Is developing a truly new nuclear fission power technology. Their KP-FHR (Kairos Power – Fluoride Salt Cooled, High Temperature Reactor) combines the solid fuel form usually associated with gas-cooled reactors with the fluoride molten salt often associated with fluid-fuel reactors.

For Atomic Show #288, my guest was Dr. Per Peterson, Kairos Power’s chief nuclear officer (CNO). Per explained the technical logic leading his company to make its ground-breaking choices.

Before describing process of making technical choices, Per provided a brief summary of the KP-FHR technological development history. The FHR originated in a conversation with MIT’s Dr. Charles Forsberg and later became the subject of an integrated research program between MIT, University of Wisconsin, and Dr. Peterson’s academic home at University of California’s Berkeley campus.

As Per was careful to point out, the program was primarily funded with Department of Energy (DOE) academic research grants and involved a number of both graduate and undergraduate research students from each of the participating institutions.

This type of project grant program is aimed at giving students practical design experience and providing purpose for experiments, equipment design and testing. Sometimes, as in the case of the FHR, members of the research team recognize that they have a product that can be commercialized because it has characteristics that are superior to similar products in the market.

Three members of the FHR integrated research project team, Per Peterson, Ed Blandford, and Mike Laufer founded Kairos Power in 2016 as a venture-funded Silicon Valley company to refine their ideas and commercialize the technology they had helped to develop within the academic setting.

In 2018, I talked with Ed Blandford and Per about Kairos Power, this show is part of my promise to provide updates on an intermittent basis.

Brief description of the KP-FHR

The nuclear fission heart of the KP-FHR is a pebble-bed reactor with 4 cm diameter fuel elements that each contain thousands of TRISO fuel particles in a graphite matrix. Fission heat generated in the reactor is moved by a pumped flow of fluoride salts through a heat exchanger that transfers the fission heat into nitrate salts similar to those used in concentrated solar thermal power systems.

The nitrate salt is pumped through a second heat exchanger (steam generator) that functions as a water boiler to produce steam with temperature of 585 ℃ and pressure of 19 MPa. As Per explained, that combination of temperature and pressure is equal to the most modern coal fired steam plants.

In fluoride salt the fuel elements have a slight positive buoyancy. To provide long operating periods without a large amount of excess reactivity at the beginning of core life, the KP-FHR includes an online fueling system that removes pebbles at the top of the core and replaces them with fresh or slightly used pebbles at the bottom.

The pebbles move slowly and have very low frictional contact with each other in the bath of molten salt. The reactor operating temperature is approximately 1000 ℃ lower than the temperature at which the TRISO fuel particles would begin releasing even small quantities of fission products, giving the reactor a broad thermal margin. As Per described it, the pebbles are so relaxed that they are almost meditating during their residence time in the molten salt.

What happened to the gas turbine concept?

Some listeners might remember that Kairos Power initially planned to use a Brayton cycle heat conversion system with the potential for using natural gas co-firing to produce peak power. Like many academic ideas, the system that looked good on paper or on computer screens turned out to be more complex and difficult to develop than expected. The current design is the result of numerous studies done with both technical and market parameters included.

Per provides a more complete version of the story and also shares the excitement that comes from working with a large, growing team of talented and motivated technologists.

What is Kairos Power’s near term plan?

One of the more exciting developments that Per shared was the fact that Kairos has been selected as a recipient for a grant under the DOE’s Advanced Demonstration Reactor Program (ADRP). Kairos will be filing a construction permit application in approximately one year to build a reduced scale version of its KP-FHR that it calls the Hermes project.

The project will be constructed on a site at the East Tennessee Technology Park near the Oak Ridge national laboratory.

DOE has promised to provide a little more than $300 million over a five year period (subject to future appropriations); Kairos will provide at least a 1:1 match of that DOE money for a project total of a about $600 million.

As might be expected, Kairos hiring and will continue to expand as it moves past laboratory scale and into a nuclear construction project.

I hope you enjoy the show. As always, comments are welcome. The conversations here often stimulate new ideas and thinking.

https://s3.amazonaws.com/AtomicShowFiles/atomic_20210122_288.mp3

Podcast: Play in new window | Download (Duration: 49:09 — 56.4MB)

Subscribe: Google Podcasts | RSS

Filed Under: Advanced Atomic Technologies, Molten salt cooled, Pebble Bed Reactors, Podcast

Atomic Show #287 – Darren Gale, VP Commercial Operations, X-Energy talks about Xe-100

November 12, 2020 By Rod Adams 2 Comments

X-Energy is the lead recipient for one of two industry groups selected to receive $80 M in Department of Energy (DOE) funding as part of a public-private partnership program to demonstrate advanced nuclear power plants on an aggressive time table. Its primary partner in the endeavor is Energy Northwest, which currently owns and operates the […]

Filed Under: Advanced Atomic Technologies, Gas Cooled Reactors, Graphite Moderated Reactors, New Nuclear, Pebble Bed Reactors, Podcast, Small Nuclear Power Plants

Turning nuclear into a fuel dominated business

October 28, 2018 By Rod Adams 66 Comments

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 […]

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

Fission heated gas turbines address MIT Future of Nuclear challenges. Easier, straighter, less costly path

September 20, 2018 By Rod Adams 57 Comments

Addressing Recommendations of MIT Future of Nuclear Energy In a Carbon Constrained World The Massachusetts Institute of Technology (MIT) is a world renowned institution that has produced thousands of highly educated engineers and scientists. It is generously supported by foundations, corporations and governments. In 2003, the MIT Energy Initiative, began publishing a series of reports […]

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

History and promise of high temperature gas cooled reactors

January 16, 2017 By Guest Author

By: Diarmuid Foley A small modular nuclear reactor to replace coal plants could be on the market within 5 years. In 2014, the Generation IV international forum[1] confirmed the Very High Temperature Reactor (VHTR) as one of 6 promising reactor technologies that should be pursued in order to develop advanced reactors suitable for deployment in […]

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

Will China convert existing coal plants to nuclear using HTR-PM reactors?

November 21, 2016 By Rod Adams

It would be a huge benefit to the earth’s atmosphere if China, India, Brazil and the US could reduce direct coal burning while still making use of much of the capital that they have invested in building coal fired power plants. It would make an even larger difference in reducing air pollution in the areas […]

Filed Under: Advanced Atomic Technologies, ANS Winter 2016, Climate change, Gas Cooled Reactors, Graphite Moderated Reactors, New Nuclear, Pebble Bed Reactors

Atomic Show #248 – Dr. Pete Pappano, VP Fuel Production X-Energy

November 20, 2015 By Rod Adams 2 Comments

On Thursday, November 19, 2015, I interviewed Dr. Pete Pappano, vice president of fuel development for X-Energy. As described in X-Energy introduced its company and first product to Virginia chapter of ANS, X-Energy is a start-up company based in Maryland that is developing a modular high temperature gas cooled reactor. Each module will produce 50 […]

Filed Under: Gas Cooled Reactors, Pebble Bed Reactors, Podcast

X-Energy introduced its company and first product to Virginia chapter of ANS

October 30, 2015 By Rod Adams 48 Comments

On Tuesday, October 27, three leaders from X-Energy spoke to the Virginia ANS chapter about their company and the Xe-100, the high temperature, pebble bed gas reactor power system that they are designing. During the presentation, meeting attendees learned that X-Energy is an early phase start-up with a total staff of a few dozen people, […]

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

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

HTR-PM – Nuclear-heated gas producing superheated steam

June 27, 2014 By Rod Adams

The first HTR-PM (High Temperature Reactor – Pebble Module), one of the more intriguing nuclear plant designs, is currently under construction on the coast of the Shidao Bay near Weihai, China. This system uses evolutionary engineering design principles that give it a high probability of success, assuming that the developers and financial supporters maintain their […]

Filed Under: Advanced Atomic Technologies, Gas Cooled Reactors, Graphite Moderated Reactors, International nuclear, New Nuclear, 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

  • Go to page 1
  • Go to page 2
  • Go to Next Page »

Primary Sidebar

Categories

Join Rod’s pronuclear network

Join Rod's pronuclear network by completing this form. Let us know what your specific interests are.

Recent Comments

  • Roger Clifton on Atomic Show #297 – Krusty – The Kilopower reactor that worked
  • Chris Aoki on Atomic Show #296 – Julia Pyke, Director of Finance Sizewell C
  • Michael Scarangella on Catching Oklo — a rising star!
  • Gary Nicholls on Atomic Show #297 – Krusty – The Kilopower reactor that worked
  • Jon Grams on Atomic Show #297 – Krusty – The Kilopower reactor that worked

Follow Atomic Insights

The Atomic Show

Atomic Insights

Recent Posts

Atomic Show #297 – Krusty – The Kilopower reactor that worked

Nuclear energy growth prospects and secure uranium supplies

Nucleation Capital’s Earth Day in Atherton

Atomic Show #296 – Julia Pyke, Director of Finance Sizewell C

Solar’s dirty secrets: How solar power hurts people and the planet

  • Home
  • About Atomic Insights
  • Atomic Show
  • Contact
  • Links

Search Atomic Insights

Archives

Copyright © 2022 · Atomic Insights

Terms and Conditions - Privacy Policy