New Nuclear Reactor Technologies

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Most current nuclear power stations use Uranium fuel in solid form in rods, with water or heavy water as coolant. Neutrons produced by the nuclear reactions are slowed down to "thermal spectrum" velocities which affects the range of nuclear reactions they produce. Reactors are large in order to produce high power outputs, but are consequently complex in order to ensure safety through multiple redundant control systems, and expensive to build. Major components including the huge pressure and containment vessels are built on-site. In most cases even reactors of the same nominal design vary from one instance to another.

Many other reactor designs are possible, and a few are being actively developed. Some build on existing water-cooled Uranium-fuelled designs but shrink and simplify the designs to make them cheaper and quicker to build with the aim of building most of the reactor itself in factories where production-line economies can be gained. Physically smaller designs can more easily be made "walk away safe", averting the risk of the sort of overheating which lead to the melt-downs at Fukushima, using only passive cooling systems. Thus although the smaller designs have lower power output they may achieve lower cost per power output and bigger power stations can simply use multiple Small Modular Reactors to give higher outputs. Because the capital cost of each SMR is much lower than that of conventional reactors the bigger power stations can be built gradually with income from completed SMR modules helping pay for expansion of the station.

Other designs differ more radically from current generation reactors: Helium is used instead of water as a heat transfer medium in High Temperature Gas Reactors, liquid sodium is used in many "breeder" reactors operating in the "fast" neutron spectrum, and many next-generation reactors are based on molten salts as coolants and often also as fuels. There are also reactor designs - particularly Molten Salt Reactors - which use Thorium rather than Uranium as fuel, and some which are designed to burn existing used nuclear fuel (which still contains much of the theoretically burnable Uranium it started with) or Plutonium (such as now-surplus nuclear bomb material).


Advanced Reactor Infromation System (ARIS)

The ARIS database includes technical information about Advanced Reactor Designs that is provided by the responsible design organizations and/or reactor plant vendors. According to the definitions established by the IAEA, an advanced reactor design consists of both Evolutionary and Innovative reactor technologies. Evolutionary reactor designs are reactor designs that improve on existing designs through small or moderate modifications with a strong emphasis on maintaining proven design features to minimize technological risk. While innovative reactor designs incorporate radical changes in the use of materials and/or fuels, operating environments and conditions, and system configurations. Advanced reactors can be classified in terms of coolant, neutron spectrum, temperature or purpose. With regards to purpose, the reactors can be sorted in terms of experimental, demonstration or prototype, and commercial.

Generation III reactor Wikipedia

Generation IV reactor Wikipedia

Generation IV Nuclear Reactors World Nuclear Association ; Jul 2016

  • An international task force is developing six nuclear reactor technologies for deployment between 2020 and 2030. Four are fast neutron reactors.
  • All of these operate at higher temperatures than today's reactors. In particular, four are designated for hydrogen production.
  • All six systems represent advances in sustainability, economics, safety, reliability and proliferation-resistance.
  • Europe is pushing ahead with three of the fast reactor designs.
  • A separate programme set up by regulators aims to develop multinational regulatory standards for Generation IV reactors.

The Advanced Nuclear Industry Samuel Brinton; Third Way; 15 Jun 2015

has comprehensive list of fission & fusion developments, comparison of technology types, and references

Tomorrow’s Nuclear Reactors are Closer Than You Think Laura Scheele, Idaho National Laboratory;; 1 Mar 2016

Advanced Reactor Nuclear Power Resurgence in the U.S.; 29 Jan 2016

White House strikes a blow for advanced nuclear reactors Richard Martin; MIT Technology Review; 20 Nov 2015

U.S. Department of Energy has announced a new program to help facilitate and finance innovation in nuclear power. Called the Gateway for Accelerated Innovation in Nuclear, the program will “provide the nuclear energy community with access to the technical, regulatory, and financial support necessary to move new or advanced nuclear reactor designs toward commercialization.”
There are nearly 50 companies in North America working on advanced nuclear reactor technologies, backed by more than $1.3 billion in private capital, according to Third Way, a Washington, D.C.-based research organization focused on energy, climate change, and national security (see “Experiments Start on a Meltdown-Proof Nuclear Reactor” and “Advanced Reactor Gets Closer to Reality”). But a lack of support from the DOE and an expensive, time-consuming licensing process under the Nuclear Regulatory Commission have presented hurdles that are all but insurmountable for startups (see “Advanced Nuclear Industry to Regulators: Give Us a Chance”).
The Gateway program, announced at the Summit on Nuclear Energy held last week at the White House, is the clearest signal to date of the Obama administration’s support for new nuclear technology. The DOE also announced it would broaden its $12.5 billion loan guarantee program for innovative nuclear technologies. These initiatives will give advanced nuclear companies access to the national laboratories, a single point of contact for collaboration with DOE experts, and help in “understanding and navigating the regulatory process for licensing new reactor technology.”

A retrospective analysis of funding and focus in US advanced fission innovation A Abdulla, M J Ford, M G Morgan, D G Victor; IOP science; 10 Aug 2017

Deep decarbonization of the global energy system will require large investments in energy innovation and the deployment of new technologies. While many studies have focused on the expenditure that will be needed, here we focus on how government has spent public sector resources on innovation for a key carbon-free technology: advanced nuclear. We focus on nuclear power because it has been contributing almost 20% of total US electric generation, and because the US program in this area has historically been the world's leading effort. Using extensive data acquired through the Freedom of Information Act, we reconstruct the budget history of the Department of Energy's program to develop advanced, non-light water nuclear reactors. Our analysis shows that—despite spending $2 billion since the late 1990s—no advanced design is ready for deployment. Even if the program had been well designed, it still would have been insufficient to demonstrate even one non-light water technology. It has violated much of the wisdom about the effective execution of innovative programs: annual funding varies fourfold, priorities are ephemeral, incumbent technologies and fuels are prized over innovation, and infrastructure spending consumes half the budget. Absent substantial changes, the possibility of US-designed advanced reactors playing a role in decarbonization by mid-century is low.

Analysis highlights failings in US's advanced nuclear program IOP Publishing; AAAS EurekAlert; 9 Aug 2017

Despite repeated promises over the past 18 years, the US Office of Nuclear Energy (NE) is unlikely to deliver on its mission to develop and demonstrate an advanced nuclear reactor by the mid-21st century.
That is the conclusion of a new study from the University of California, San Diego and Carnegie Mellon University, published today in the journal Environmental Research Letters, which used data obtained through the Freedom of Information Act to reconstruct the program's budget history.
Lead researcher Dr Ahmed Abdulla, from UC San Diego, said: "In theory, advanced, non-light water reactors are a promising carbon-free technology, which could complement or replace light water reactors. Some of these reactors would operate at higher temperatures, providing energy services that existing reactors cannot. Others, meanwhile, could reduce future nuclear waste burdens by operating for decades without refuelling, burning up more of their fuel and generating smaller volumes of waste.
"However, despite repeated commitments to non-light water reactors, and substantial investments by NE (more than $2 billion of public money), no such design is remotely ready for deployment today."
The researchers investigated how effectively those resources were allocated, and how NE has performed as a steward of nuclear technology innovation. What they found was an office beset by problems and violating much of the wisdom about how to effectively run an applied energy research program.
Dr Abdulla said: "There were often inconsistencies in the annual budget documents. The budget itself varies significantly over the period of study, which is fine if these variations are part of a coherent vision that is being pursued, but that is not the case. At all levels, NE favours existing technologies and fuels over innovation, and, where it does support truly innovative research, it is prone to changing priorities before any concrete progress has been made.

Next Steps for Nuclear Innovation in the UK Stephen Tindale, with Katherine Chapman and Suzanna Hinson; Weinberg Next Nuclear; Apr 2016

Nuclear energy makes a major contribution to UK energy security. Existing civil nuclear reactors provide clean, low carbon energy, mitigating the problems of air pollution and climate change. But they have high upfront capital costs, and are not sufficiently flexible to back up wind and solar power. Significant progress on advanced nuclear energy technologies over the next ten years would address these drawbacks and contribute substantially to a more secure and sustainable UK energy system. However, advanced nuclear should be pursued as well as - not instead of - new nuclear facilities using existing nuclear technology. Advanced nuclear is not yet ready to fill the entire gap created as current UK nuclear facilities reach the end of their design life.
Advanced nuclear reactors could deliver energy that is even lower-carbon than energy from existing nuclear designs. They could be inherently and passively safe and have a significantly reduced proliferation risk. They would be cheaper to build than the EPR, and very probably cheaper than any existing nuclear design. They could be a means of re-using spent fuel and reducing the UK’s plutonium stockpile.
Includes summary of some new generation designs
Charles Barton's comments on Weinberg report:
Next Step for Nuclear innovation in the UK is a deeply flawed document prepared for the British Government by the Weinberg Institute as a policy guide intended to assist the Government of the UK on future choices regarding advanced nuclear technology. Unfortunately, the Weinberg Institute lacks the Depth of Alvin Weinberg, the famous Nuclear Scientist for which it is named. Below is a link to this document. I will focus here of the criteria by which this document suggests future nuclear decisions should be based. Next Step places two Safety and proliferation prevention above other categories. But Generation III + reactors are already highly safe, indeed safer than renewable generation technologies, and minimal safety standards for Generation IV reactors are in some cases even safer. Efficiency requirements might well produce generation IV reactors that meet absurdly safe standards. So why make safety more important than other considerations. The second standard is the prevention of nuclear proliferation. Yet we are talking her about Reactors to be built in the UK, the United States and Canada. The first two countries are already nuclear powers, while the third country has possessed the ability to build nuclear weapons since WW II, but has refrained to do so. The reactors built in these three countries are very unlikely to cause nuclear proliferation, and one way to avoid proliferation from Generation IV technology built in any of these countries, is an agreement between the three of them to not sell Generation IV reactors to any State that is likely to embark on nuclear weapons programs. A further consideration is that the Chinese are working on development projects involving 3 different types of Generation IV reactor technology. Unless brought into proliferation prevention arrangements, China could sell Generation IV reactors to countries known to pose proliferation risks. Clearly there are problems with this study.

Floating reactors


Bohai Shipbuilding Industry to build China’s first offshore nuclear platform Jason Jiang; Splash 24/7; 20 Apr 2016

China Shipbuilding Industry Corporation (CSIC) has confirmed that it will construct the first offshore nuclear platform at its affiliate yard Bohai Shipbuilding Industry. Currently Bohai Shipbuilding Industry is collaborating with China General Nuclear Power Corporation (CGN) for the preliminary works of the project. CSIC-No.719 Research and Development Institute has completed two designs for the platform, one is a floating platform and the other is a submersible platform. CGN has been developing a small modular nuclear reactor called the ACPR50S for maritime use, which would be able to provide power to offshore oil and gas exploration and production. The investment on the project is about RMB3bn ($464m), and the first platform is expected to start a trial in 2019. China also made plans to build 20 offshore nuclear platforms in the near future. Bohai Shipbuilding is one of China’s more secretive yards, tasked with plenty of military contracts as well as commercial vessel construction.

China Plans A Floating Nuclear Power Plant James Conca; Forbes; 18 Jan 2016

A 200MW light water reactor for electrical power, desalination etc.

Lloyd's Register to help Chinese develop floating SMR World Nuclear News; 26 Oct 2015

Lloyd's Register of the UK announced today it has signed a framework agreement with the Nuclear Power Institute of China (NPIC) to support the design and development of a floating nuclear power plant utilizing a small modular reactor (SMR).
Under the framework agreement, Lloyd's Register and NPIC - a subsidiary to China National Nuclear Corporation (CNNC) - will cooperate on the development of the "first-of-a-kind floating nuclear vessel" which will be used in Chinese waters to supply electrical power to offshore installations.
Lloyd's Register said the first contract under the framework agreement is to develop new safety regulations, safety guidelines, and nuclear code and standards for the floating vessel, that are consistent with Offshore and International Marine Regulations and the International Atomic Energy Agency (IAEA) nuclear safety standards.


Russia to Build World's First Floating Nuclear Power Plant Next Year The Moscow Times; 21 Apr 2015

Russia starts work on Arctic dock for 1st-ever floating nuclear power plant RT; 7 Oct 2016

The world’s first floating nuclear power plant is set to start producing power and heat in 2019. While the plant is already being tested, construction of the dock has begun on the Arctic coast in Russia’s Far East. The construction works on the dock, which will host the floating nuclear power plant ‘Akademik Lomonosov’, kicked off Wednesday in the bay of the city of Pevek, Chukotka, RIA Novosti reports.

Russia's Floating Nuclear Power Plant Has Hit the Sea Jennings Brown; Gizmodo; 30 Apr 2018

Russia launched the world’s first floating nuclear power plant on Saturday. The 70-megawatt vessel, christened the Akademik Lomonosov, was towed away from St. Petersburg by two boats. It is currently coasting through the Baltic Sea to the town of Murmansk for fuel, and is then supposed to embark for the Arctic town of Pevek in 2019, according to a release from the state-run firm that built the rig.

Washington State SMRs

Washington State continues looking into small modular reactors nuScale, mPower

Advanced Boiling Water Reactor

One step closer to building an Advanced Boiling Water Reactor (ABWR) in the UK The Alvin Weinberg Foundation

Travelling Wave Reactor / TerraPower

Traveling Wave Reactor Wikipedia


Bill Gates explains why China will build the first fourth generation nuclear plant

Fast / Breeder reactors

Lead cooled

Lead cooled fast reactor Wikipedia

Swedish: Sealer


SEALER (Swedish Advanced Lead Reactor) is a lead-cooled reactor designed with the smallest possible core that can achieve criticality in a fast spectrum using 19.9% enriched uranium oxide (UOX) fuel. The rate of electricity production may vary between 3 to 10 MW, leading to a core-life between 10 and 30 full power years (at 90% availability). The reactor is designed to maintain a maximum temperature of the lead coolant below 450°C, making corrosion of fuel cladding and structural materials a manageable phenomenon, even over a life-span of several decades.
The safety features of lead mean that the core can manage a complete loss of off-site power for weeks before integrity of the fuel rods is challenged. Should any volatile fission products be relesead into the coolant, 99.99% will be chemically retained by the lead. The eventual release of noble gases and residual volatiles results in a radiological exposure at the site boundary which is smaller than the natural back-ground dose received during a few months. Hence, no accident scenario can lead to a situation where evacuation becomes necessary.
LeadCold entered Phase 1 of the Canadian Nuclear Safety Commission’s pre-license review in December 2016. The eventual objective is to receive a license for construction in Canada by end of 2021, aiming at having our first SEALER-unit ready for operation in 2025.
The future cost for purchasing a SEALER reactor is estimated at 100 million Canadian dollars.
Waste management
After 10 - 30 years of operation, the first SEALER units will be transported back to a centralised recycling facility. The plutonium and minor actinides present in the spent fuel may then be separated and converted into an inert matrix nitride fuel for indefinite recycle in SEALER reactors. The residual high level waste (mainly short lived fission products) will be vitrified and isolated from the biosphere in a geological repository for a period of less than 1000 years.

Canada set for first lead-cooled reactor by 2025 after $200mn funding boost Nuclear Energy Insider; 8 Mar 2017

LeadCold plans to use the large investment by Indian conglomerate Essel Group to fund pre-licensing, detailed engineering design, and development costs for a 3 MW demonstration reactor ahead of deployment on remote sites, Janne Wallenius, CEO of LeadCold, told Nuclear Energy Insider in an interview.
A number of advanced nuclear reactor developers are targeting the Canadian market, where the risk-informed regulatory framework is considered more supportive for licensing new designs than in the U.S. and where numerous remote communities and industrial facilities represent captive electricity consumers.
In late December LeadCold filed its fast neutron Swedish Advanced Lead Reactor (SEALER) design with the Canadian Nuclear Safety Commission (CNSC) for phase 1 of the pre-licensing review.
LeadCold aims to deploy its reactors within the remote Arctic regions in the Northwest Territories and Nunavut, where power users are off-grid and depend on high-cost diesel-fired generators.
The company, a spin off from the Royal Institute of Technology in Stockholm (KTH), is developing a reactor that can provide a capacity of between 3 MW and 10 MW, to meet the different power needs of remote communities and mining customers.
The Levelized Cost of Energy (LCOE) is estimated at C$450/MWh ($337/MWh) for 3 MW capacity and C$220/MWh for 10 MW, Wallenius told Nuclear Energy Insider in an interview.
Electricity costs can be as high as C$2,000/MWh in the most remote regions of Northern Canada, Roger Humphries, director of SMR Development for Amec Foster Wheeler, said in an interview in January 2016.
Some 200,000 people live in over 200 remote communities and 80% of their power comes from diesel-fired generators.

Sodium cooled

Sodium cooled fast reactor Wikipedia

UK: Dounreay

Dounreay Wikipedia


Westinghouse announces Lead Cooled Fast Reactor initiative Will Davis; atomic power review; 9 Oct 2015

On Friday, October 9, Westinghouse announced that it had launched a program to work with the US Department of Energy in the development of a new, lead-cooled fast reactor (commonly, "LFR") which would combine the advantages of lead cooling (high temperatures, primarily, as well as lower pressures) with advanced accident tolerant fuel to push the Gen-IV envelope to what it perceives as Gen-V -- a term that seems to imply the "state of the art" in perhaps 30 or 50 years down the road.

Westinghouse proposes LFR project World Nuclear News ; 14 Oct 2015

Westinghouse is seeking to collaborate with the US Department of Energy (DOE) on the development of a lead-cooled fast reactor (LFR). It will be the company's first foray into fourth generation reactor designs.
The company announced on 8 October that it had submitted a project proposal for the LFR under the DOE's Advanced Reactor Industry Competition for Concept Development funding opportunity.
Westinghouse said that its project team includes members of the national laboratory system, universities and the private sector "with expertise in areas essential to the design and commercialization of an advanced LFR plant".
The Westinghouse LFR would be "designed to achieve new levels of energy affordability, safety and flexibility", the company said. In addition to featuring accident-tolerant fuel, the reactor's use of lead as a coolant "will further enhance reactor safety, and optimize the plant's economic value through lower construction costs and higher operating efficiency than other technologies", it said.
In addition to electricity generation, the Westinghouse LFR could be used for hydrogen production and water desalination, the company noted. It also said the reactor's load-following capabilities "would further support the increased use of renewable energy sources".

PRISM / IFR Breeder

GE and Hitachi want to use nuclear waste as a fuel Lin Edwards;; 18 Feb 2010


Russian BN-800 etc

The BN-800 Fast Reactor – a Milestone on a Long Road Syndroma; Energy Matters; 4 November 2016

Guest post by Russian commenter Syndroma who was trained in IT and now works in his family business. The BN-800 was commissioned this week.


Chinese fast reactor starts supplying electricity World Nuclear News; 21 Jul 2011

Exactly one year after achieving first criticality, China's experimental fast neutron reactor has been connected to the electricity grid.
The sodium-cooled, pool-type fast reactor has been constructed with some Russian assistance at the China Institute of Atomic Energy (CIEA), near Beijing, which undertakes fundamental research on nuclear science and technology. The reactor has a thermal capacity of 65 MW and can produce 20 MW in electrical power. The CEFR was built by Russia's OKBM Afrikantov in collaboration with OKB Gidropress, NIKIET and Kurchatov Institute.
Xu Mi, chief engineer at the CEFR program at CIEA, told Bloomberg that the unit was connected to the grid at 40% capacity. "The next step for us is to increase the generating capacity of the reactor to 100% while connected to the grid," he said. "After that, we can use the technology to build our own commercial fast reactors."
Beyond the pilot plant, China once planned a 600 MWe commercial scale version by 2020 and a 1500 MWe version in 2030 but these ambitious ideas have been overtaken by the import of ready-developed Russian designs. In October 2009, an agreement was signed by CIAE and China Nuclear Energy Industry Corporation (CNEIC) with AtomStroyExport to start pre-project and design works for a commercial nuclear power plant with two BN-800 reactors with construction to start in August 2011, probably at a coastal site. The project is expected to lead to bilateral cooperation of fuel cycles for fast reactors, which promise to vastly extend the fuel value of uranium as well as reduce radioactive wastes.


Thorium fuel cycle — Potential benefits and challenges International Atomic Energy Agency; May 2005

Thorium is three times more abundant in nature compared to uranium and occurs mainly as ‘fertile’ 232Th isotope. From the inception of nuclear power programme, the immense potential of 232Th for breeding human-made ‘fissile’ isotope 233U efficiently in a thermal neutron reactor has been recognized. Several experimental and prototype power reactors were successfully operated during the mid 1950s to the mid 1970s using (Th, U)O2 and (Th, U)C2 fuels in high temperature gas cooled reactors (HTGR), (Th, U)O2 fuel in light water reactors (LWR) and Li7 F/BeF2/ThF4/UF4 fuel in molten salt breeder reactor (MSBR). 232Th and 233U are the best ‘fertile’ and ‘fissile’ materials respectively for thermal neutron reactors and ‘thermal breeding’ has been demonstrated for (Th, U)O2 fuel in the Shippingport light water breeder reactor (LWBR). ThO2 has also been successfully used as blanket material in liquid metal cooled fast breeder reactor (LMFBR) and for neutron flux flattening of the initial core of pressurized heavy water reactor (PHWR) during startup. So far, thorium fuels have not been introduced commercially because the estimated uranium resources turned out to be sufficient. In recent years, there has been renewed and additional interest in thorium because of: (i) the intrinsic proliferation resistance of thorium fuel cycle due to the presence of 232U and its strong gamma emitting daughter products, (ii) better thermo-physical properties and chemical stability of ThO2, as compared to UO2, which ensures better in-pile performance and a more stable waste form, (iii) lesser long lived minor actinides than the traditional uranium fuel cycle, (iv) superior plutonium incineration in (Th, Pu)O2 fuel as compared to (U, Pu)O2 and (v) attractive features of thorium related to accelerated driven system (ADS) and energy amplifier (EA). However, there are several challenges in the front and back end of the thorium fuel cycles. Irradiated ThO2 and spent ThO2-based fuels are difficult to dissolve in HNO3 because of the inertness of ThO2. The high gamma radiation associated with the short lived daughter products of 232U, which is always associated with 233U, necessitates remote reprocessing and refabrication of fuel. The protactinium formed in thorium fuel cycle also cause some problems, which need to be suitably resolved. The information on thorium and thorium fuel cycles has been well covered in the IAEATECDOC-1155 (May 2000) and IAEA-TECDOC-1319 (November 2002). The objective of the present TECDOC is to make a critical review of recent knowledge on thorium fuel cycle and its potential benefits and challenges, in particular, front end, applying thorium fuel cycle options and back end of thorium fuel cycles.

A safer route to a nuclear future?; 13 Jun 2012

discussion of recycling actinides as fuel, safety problems with multiple cycles with U fuel that Th fuel could solve, Ben Lindley, Cambridge Enterprises

Thorium-Fuelled Molten Salt Reactors Report for the All Party Parliamentary Group on Thorium Energy; The Weinberg Foundation; Jun 2013

Thorium-fuelled Molten Salt Reactors (MSRs) offer a potentially safer, more efficient and sustainable form of nuclear power. Pioneered in the US at Oak Ridge National Laboratory (ORNL) in the 1960s and 1970s, MSRs benefit from novel safety and operational features such as passive temperature regulation, low operating pressure and high thermal to electrical conversion efficiency. Some MSR designs, such as the Liquid Fluoride Thorium Reactor (LFTR), provide continuous online fuel reprocessing, enabling very high levels of fuel burn-up. Although MSRs can be fuelled by any fissile material, the use of abundant thorium as fuel enables breeding in the thermal spectrum, and produces only tiny quantities of plutonium and other long-lived actinides.
Current international research and development efforts are led by China, where a $350 million MSR programme has recently been launched, with a 2MW test MSR scheduled for completion by around 2020. Smaller MSR research programmes are ongoing in France, Russia and the Czech Republic. The MSR programme at ORNL concluded that there were no insurmountable technical barriers to the development of MSRs. Current research and development priorities include integrated demonstration of online fuel reprocessing, verification of structural materials and development of closed cycle gas turbines for power conversion.

Thor-bores and uro-sceptics: thorium's friendly fire Jim Green − Nuclear Monitor editor; Nuclear Monitor Issue: #8014458; 9 Apr 2015

Many Nuclear Monitor readers will be familiar with the tiresome rhetoric of thorium enthusiasts − let's call them thor-bores. Their arguments have little merit but they refuse to go away.

The U.S. government lab behind China's nuclear power push Reuters; 20 Dec 2013

Thorium molten salt reactors in EenVandaag - Dutch Public Television 20151105 Gijs Zwartsenberg

Thorium Energy Report website with pages of reports on work on Thorium reactors from:

Thorium can give humanity clean, pollution free energy Kirk Sorensen; TEDxColoradoSprings

Thorium Energy World - papers

127 mostly quite technical papers presented during the Thorium Energy World conference
Grouped by subject area. Links to full papers where author(s) permit.

Small Modular Reactors


Aristos website

Aristos Power's revolutionary modular nuclear reactor design will provide a clean, cheap, safe and highly scalable energy source.
Modular design
Going from ultra compact cores of 20 MWe capable of powering isolated strategic locations, to compact 200 MWe utility scale reactors and up to 2000 MWe reactors designed to power major industrial hubs, our reactors can cover a wide range of energy needs.
The simple, easy to manufacture, modular design presents significant economic advantages. The overnight price tag per unit varies depending on the capacity of the unit going from 4.5$/W for the 20 MW unit down to 3$/W for the 200 MW unit and further down to 2$/W for the 2000 MW version. The price of electricity calculated over a service period of 40 years at a capacity factor of 95% is set to be around 1 cent / kWh.
Walk Away Safe
Our core design represents a revolution in reactor safety, in addition to the already established robust passive safety features of molten salt reactors, our team developed an additional passive safety system which ensures that in the unlikely event of a core breach there is no possibility of a recriticality accident.
UPDATE 20/10/2017
Today a milestone has been reached, the completion of the conceptual design phase.

We proudly present you the Hard Spectrum Reactor 50 Mk.9, v.25

facebook post & discussion

Lead cooled
Ike Bottema Yes apparently. It's 50MWth
no clue is offered as to where this crew is from. Could be a guy in a basement somewhere hoping to drum up some interest in his idea for all I know.
Ed Pheil First question, if it is Pb or PbBi, is what temperature, and what material? Pb can get to extremely high power densities, like 400-1000MWth/liter, but that is not passive cooling.
I'm guessing much lower power density, and Fe-Cr-Mo (corrosion limited) or Fe-Cr-Al (creep limited), likely 450-500C max temperature, so cooler than sodium, and m7ch cooler than molten salts, so maybe 35-40% efficiency. Is that two loops in the vessel, or one loop with iron/Pb reflector with Hx outside of that. Looks like little to no natural circulation, but might just use conduction. Not sure the latter works without refractory metal core because long distance conduction takes a good bit of delta T.
Andrei D. Andrei Pb only, 700-750 C, yes, much lower power densities, cant discuss material here, yes, 2 loops, there is a reflector but not iron , and circulation is forced during normal operation and natural circulation after scram.


SMALL MODULAR REACTORS (SMRS) (US) office of Nuclear Energy (

Small Modular Reactors (SMRs) are nuclear power plants that are smaller in size (300 MWe or less) than current generation base load plants (1,000 MWe or higher). These smaller, compact designs are factory-fabricated reactors that can be transported by truck or rail to a nuclear power site. SMRs will play an important role in addressing the energy security, economic and climate goals of the U.S. if they can be commercially deployed within the next decade.

Advancing Small Modular Reactors: How We're Supporting Next-Gen Nuclear Energy Technology US Department of Energy infographic on SMR (showing pressurised water reactor type)

California entrepreneurs push to reinvent the nuclear industry UPower , Transatomic


Canada signs flurry of SMR contracts as innovation support widens Nuclear Energy Insider] 1 Nov 2017

After a surge of SMR proposals, Canadian Nuclear Laboratories has started research work to support four different design technologies and is working with public and industry partners to support deployment in remote locations and mining applications.
Canada's SMR development program is advancing at a rapid rate, as developers respond to ambitious research initiatives, supportive regulatory regimes and a wide variety of deployment opportunities.
CNL has designated SMR technology as a research priority and aims to build a demonstration SMR plant on site by 2026. A recent Request for Expressions of Interest (RFEOI) by CNL yielded responses from 80 SMR vendors, suppliers, academics and potential end-users.
CNL received 19 expressions of interest for a prototype or demonstration reactor at a CNL site and a further three developers propose to move straight to commercial deployment in Canada, CNL said in a report published October 17.
CNL has so far signed MOU's with seven companies to develop and site an SMR at a CNL facility and projects are already underway to support four different reactor types, CNL sources have told Nuclear Energy Insider.


Bechtel And BWXT Quietly Terminate mPower Reactor Project Rod Adams; Forbes; 13 Mar 2017

Generation mPower, one of the early leaders in the development of small modular reactors (SMR), has decided to fully terminate its partnership and put the design material that was developed onto a corporate shelf.
Generation mPower was a partnership between BWXT – which was a part of The Babcock & Wilcox Company when the partnership was first formed – and Bechtel. BWXT owned 90% of the equity in the partnership and was responsible for designing the nuclear steam supply system, which is the nuclear fuel core, the piping and heat exchangers and the operating machinery inside the containment building. Bechtel owned 10% and was responsible for designing the structural parts of the containment building, all of the buildings and internal systems for the steam system, and the site support systems. Bechtel also provided its project management expertise, including occupying what is often the most powerful position in any partnership, that of the comptroller with the final say in any major expenditure decision. The companies worked closely together to design the site layout with an eye towards meeting stringent security and aircraft impact requirements in a cost and manpower effective way.


Small Modular Reactors Competition Phase One Department for Business, Energy & Industrial Strategy; 2016

A competition to identify the best value Small Modular Reactor design for the UK

The UK’s Small Modular Reactor Competition Andy Dawson; Energy Matters; 15 Jun 2016

The UK government has launched a competition to select a design of a small modular reactor (SMR) for future deployment in the UK. In this post, nuclear engineer Andy Dawson provides an overview of SMR technology together with descriptions of the leading contenders.

Bus-sized nuclear reactors could replace large-scale plants Tereza Pultarova; Engineering & Technology; 23 Aug 2016

Instead of building the £18bn Hinkley Point power plant, the UK should consider investing into the development of small nuclear reactors that could be deployed across the country to balance out intermittent renewable energy generation, energy experts have suggested.

UK sets up £250 million research for small modular nuclear reactors and will likely partner with China NextBigFuture

Small Modular Reactors feasability study National Nuclear Lab; Dec 2014

Mini nuclear power stations in UK towns move one step closer Kate McCann; Daily Telegraph; 2 Apr 2016

The Telegraph understands that a team of experts working for Ministers is looking at possible locations for small modular reactors, which could be built by 2025.

Nuclear developers have big plans for pint-sized power plants in UK Susanna Twidale; Reuters; 22 Aug 2016

A range of mini-nuclear power plants could help solve Britain's looming power crunch, rather than the $24 billion Hinkley project snarled up in delays, companies developing the technology say. So-called small modular reactors (SMRs) use existing or new nuclear technology scaled down to a fraction of the size of larger plants and would be able to produce around a tenth of the electricity created by large-scale projects, such as Hinkley. The mini plants, still under development, would be made in factories, with parts small enough to be transported on trucks and barges to sites where they could be assembled in around six to 12 months, up to a tenth of the time it takes to build some larger plants.

Westinghouse expands SMR study team World Nuclear News; 12 Oct 2016

Westinghouse will work with UK shipbuilder Cammell Laird as well as the country’s Nuclear Advanced Manufacturing Research Centre (NAMRC) on a study to explore potential design efficiencies to reduce the lead times of its small modular reactor. The reactor vendor has already worked with NAMRC on a study that concluded the reactor pressure vessels for its SMR design could be made in Britain - a potentially important element in its offer to government in hope of winning a competition towards SMR demonstration. The new study will be a continuation, said Westinghouse. New to the project is Cammell Laird, a shipbuilder based in Liverpool that has been increasing its involvement in the UK's nuclear sector for several years. In 2010 it agreed to work with Nuvia towards manufacture of modules for decommissioning and for new build, and in 2011 the pair were joined by Ansaldo Nucleare of Italy, which is experienced in AP1000 work. This is in addition to Cammell Laird's ongoing work in offshore oil, gas and wind.

NuScale Makes Progress in UK and US Markets / UK Market May Finally Open Up for SMRs Neutron Bytes; 10 Sep 2017

On September 9th the Telegraph reported in its business pages the government ministers are getting ready to approve the development of a fleet of “mini” reactors to prevent electricity shortages as older nuclear power stations are decommissioned.
The newspaper noted that advocates for the new technology expect it to offer energy a third cheaper than giant conventional reactors such as the Hinkley Point project which is composed of two Areva 1650 MW EPRs.
The firms involved in the SMR meeting include Rolls-Royce, NuScale, Hitachi and Westinghouse. They have held meetings in past weeks with civil servants about Britain’s nuclear strategy and development of “small modular reactors” (SMRs).
A report to be published by Rolls-Royce in Westminster this week claims its consortium can generate electricity at a “strike price” – the guaranteed price producers can charge – of £60 per megawatt hour, two thirds that of recent large-scale nuclear plants.
The report to be published by Rolls-Royce, entitled “UK SMR: A National Endeavour”, which has been seen by The Telegraph, claims SMRs will be able to generate electricity significantly cheaper than conventional nuclear plants.


Westinghouse expands SMR study team World Nuclear News; 12 Oct 2016 12 October 2016

The Westinghouse SMR is a 225 MWe integral pressurized water reactor design with all primary components located inside the reactor vessel. It uses the passive safety functionality developed for the company's AP1000 reactor, currently being built at sites in China and the USA.


Integral Pressurised Water Reactor with 45MW electrical output, built-in (steam?) generator, to operate underground in a pool of water providing emergency cooling.


Small Modular Reactors - A Small Modular Reactor programme represents a once in a lifetime opportunity for the UK Rolls Royce

Rolls-Royce could power Britain's nuclear future with mini reactors Alan Tovey, industry editor; Daily Telegraph; 19 MAR 2016

Rolls-Royce is positioning itself as a “white knight” that could rescue Britain’s faltering nuclear power strategy and stop the UK’s lights going out. The company best known for its jet engines has met with Government to put forward plans for a fleet of small reactors built around Rolls’s expertise gained producing powerplants for the Royal Navy's submarines.

The role for nuclear within a low carbon energy system Mike Middleton; Energy Technologies Institute

SMRs could fulfil an additional role in a UK low carbon energy system by delivering combined heat and power (CHP) – a major contribution to the decarbonisation of energy use in buildings – but deployment depends on availability of district heating infrastructure.

Rolls-Royce all set to unveil British SMR consortium World Nuclear News; 3 Oct 2016

Rolls-Royce will in the "coming weeks" announce the consortium it has formed to launch a small modular reactor in the UK, a spokesman for the British company told World Nuclear News today.


One UK SMR power station will produce 440MWe

Designs for 'mini' nuclear power plants proposed by Rolls-Royce led group set to be given go-ahead Alan Tovey; The Telegraph; 22 Oct 2017

n important report assessing the viability of new “mini” nuclear power plants for the UK to be published this week is expected to give the green light to develop designs proposed by a British consortium led by Rolls-Royce. The Department for Business, Energy and Industrial Strategy (BEIS) is set to issue a study which formally ends a competition between different types of low-carbon power generation to assess which should be supported. Industry sources say a concurrent Techno-Economic Assessment for the government by EY concludes that designs for small nuclear reactors (SMRs) from the Rolls consortium are the more likely to succeed. It is understood that rival proposals using US designs for “integral reactors” have been assessed as being harder to manufacture and maintain and not commercially viable.

Korean SMART

Bizline-Korean style small and medium scale nuclear reactor "SMART"

Korean style small and medium scale nuclear reactor "SMART"
South Korea has opened the way to export small and medium scale nuclear reactors developed with homegrown technology. Dubbed "SMART," for System-integrated Modular Advanced ReacTor, the world′s first small and medium scale reactor prevents radioactive substances from leaking out during accidents such as earthquakes as it is an integral structure that has enclosed the major components in the pressure vessel. "SMART" has been highlighted as a next-generation reactor for its safety, performance and construction costs which is one fifth that of large scale reactors. We′ll take a look at the technology behind the reactor and its prospects.
(Cost shown as c.1bn for c.100MW)

Korean supercritical CO2 cooled

Supercritical CO2-cooled micro modular reactor; 9 Mar 2016

A research team at Korea Advanced Institute of Science and Technology (KAIST) (Prof. Jeong Ik Lee, Prof. Yonghee Kim, and Prof. Yong Hoon Jeong) has suggested an innovative concept of a reactor cooled by supercritical state carbon dioxide (S-CO2). The core has long life (20 years) without refuelling as well as inherent safety features. The S-CO2 Brayton cycle was proposed as a power conversion system to achieve a compact and lightweight module. Due to the compact core and power conversion system, the entire system can be contained in a single module and be transported via ground or maritime transportation.

General Atomics

Energy Multiplier Module

Waste burner, Brayton cycle power conversion (claims 50% efficiency) or process heat; 30 year fuel cycle; variety of fuels: enriched U, weapons grade Pu, depleted U, Th, used nuclear fuel, "its own discharge". Tech data


The scientists and engineers at General Atomics think the future of nuclear energy is coming on the back of a flatbed truck. And the leadership at the San Diego-based company, which has been developing nuclear technologies for more than 60 years, has already spent millions in the expectation that its ambitious plans for the next generation of reactors will actually work.

URENCO U-battery

Miniature nuclear power stations available within decade Tereza Pultarova; E&T Magazine; 7 Oct 2016

uranium enrichment firm URENCO has decided to go even further and develop a miniature nuclear power plant so small and cheap that it could power a single village or a factory
“A single unit would occupy an area the size of two squash courts,” explained Paul Harding of URENCO, overseeing the project called U-Battery. “The footprint of each unit is about the penalty area of a football pitch. Each unit is designed to give 10 megawatts of thermal output of which around 40 per cent can be converted into electricity, so you can get four megawatts of electricity from a single installation.”
Unlike the larger SMRs, U-battery is a high temperature gas cooled reactor akin to currently developed generation IV nuclear reactors. It uses grain-like TRISO fuel that is not designed for reprocessing but spent after one use.
“The U-Battery is designed to operate at about 700℃ and you do not challenge integrity of the fuel to at least 1600℃ so there is a great margin,” Harding said. “TRISO fuel is inherently safe. It consists of grains of uranium oxide that are coated in three layers of ceramic material, which ensures that fission products do not escape from the inner kernel.”
The remotely controlled U-battery was designed with renewable energy generation in mind and the team envisions it could serve as a back-up power generator for solar and wind power plants.
The team is already negotiating with authorities of the Canadian province of Ontario to have U-Batteries tested in some of the remote northern communities that are not connected to the utility grid.

Kilopower (KRUSTY) space reactor

Kilopower Wikipedia

KiloPower is a NASA and Department of Energy’s National Nuclear Security Administration (NNSA) project aimed at producing a new design for nuclear reactors for space travel. The project started in October 2015. The Kilopower reactors will come in a variety of sizes able to produce from one to 10 kilowatts of electrical power, continuously for 10 years or more. The fission reactor uses Uranium-235 to generate heat that is carried to the Stirling converters via passive sodium heat pipes.

KRUSTY: First of a New Breed of Reactors, Kilopower Part II Beyond Nerva (blog); 19 Nov 2017

... in-space nuclear reactors have been flown before, mainly by the USSR, and their development in the West has stalled in terms of testing since the 1970s. However, a recent (2012) test at the National Nuclear Security site by scientists and engineers from the Department of Energy (DOE) and NASA, the Desktop Using Flattop Fission test (DUFF), has breathed new life into the program by demonstrating new heat transport and power conversion techniques with a nuclear reactor for the first time.
Now, the results of this experiment are being used to finalize the design and move forward with a new reactor, the Kilowatt Reactor Utilizing Stirling TechnologY, or KRUSTY. This is an incredibly simple small nuclear reactor being developed by Los Alamos National Laboratory (LANL) for the DOE, and Glenn Research Center (GRC) and Marshall Spaceflight Center (MSFC) for NASA. KRUSTY: We Have Fission! Kilopower part III] Beyond Nerva (blog); 2 May 2018

KRUSTY is the testbed for the Kilopower reactor, developed by Los Alamos as a small, simple nuclear reactor meant for space missions (although it also has terrestrial uses as well, and two companies have proposed similar, but larger architectures since: Oklo Power and Westinghouse). After an initial proof of concept fission test (DUFF), KRUSTY was designed and built by NASA (at the Glenn Research Center in Cleveland), and the Department of Energy (Y12 in Tennessee fabricated the core, and Los Alamos was the lead design site), and just last month completed fission powered testing at the National Nuclear Security Site (NNSS) in Nevada.

Molten Sodium Reactors

Some Fast Breeder Reactors, and TerraPower's Traveling Wave Reactor use molten sodium as coolant.

Sodium safety

Metal Fires in Fast Reactors: Part I Tara J. Olivier, Ross F. Radel, Steven P. Nowlen, Thomas K. Blanchat, John C. Hewson; Nuclear Green Revolution; 23 Feb 2015

Refers to report by Sandia Labs

Criticism of Sodium-cooled reactor designs by Robert Steinhaus

The Short of Why I do not like the Terrapower TWR pool style SFR
(Safety Concern) - Sodium Cooled Fast Reactors like the Terrapower TWR contain a lot of reactive sodium coolant.
The French Superphenix used 5500 metric tons of sodium (3300 tons in the primary reactor vessel) for a 1.2 GWe reactor - exact figures have not so far been provided for other mature SFR designs like GE PRISM, BN-800, or the Terrapower TWR so scaling the Superphenix numbers is about the best analysts can do given the reticence of current SFR designers to reveal to the public and decision makers the numbers that would allow fair and accurate analysis of the potential hazard of their SFR designs.
Sodium Safety - Sodium reacts exothermically with liquid water or steam to generate sodium hydroxide and hydrogen:
Na + H2O -> NaOH + 1/2H2 + heat Heat of reaction: ~ 162kJ/mole-Na (around 7.05MJ/kg-Na)
Hydrogen tends to accumulate in the roof area of a reactor containment building and if the conditions are right, hydrogen air mixtures can detonate.
Reference – G. Manzini and F. Parozzi “Sodium Safety” (Intrinsically safer nuclear technology exits)-
A 1 GWe Pu-239 fueled Sodium Cooled Reactor, like the Terrapower TWR, fissions about 1 ton of Pu-239 fuel while producing about 1 ton (1000 kilograms) of fission products a year. The Terrapower TWR is designed to retain spent fuel inside the reactor and "shuffle fuel" while operating. One effect of this arrangement is that over the designed lifetime of the reactor, more and more fission products accumulate.After 60 years of operation, some of the early produced fission products inside the TWR will have decayed to lower levels of activity - becoming less radioactive. On the other hand, depending on the specific arrangements of the fuel shuffling system used in the TWR, old fission products which are exposed to neutrons will continue to absorb neutrons and become further neutron activated, in some instances making them more radioactive. A more complex modeling of 60 year isotopic inventory of a Terrapower TWR would need to be made with a code like ORIGEN-S to give a reliable and accurate assessment of radioactivity of the fission product isotopic inventory after 60 years of operation. Still, I think it can be fairly stated that the radiological inventory of a sodium cooled TWR would be very large indeed and the chemical stored energy in Sodium coolant also very large which means that the potential is there for a really large accident (INES-7) if any of the SFR engineered safety systems (like the Argon cover gas over the main reactor sodium pool) is ever even momentarily lost as the result of an air leak..
Safer reactor coolants than hot reactive sodium exist (I like Molten Salts or helium).

Molten Salt Reactors

Molten Salt Reactors Nick Touran

Molten Salt Reactors (MSRs) are nuclear reactors that use a fluid fuel in the form of very hot fluoride or chloride salt instead of the solid fuel used in most reactors. Since the fuel salt is liquid, it can be both the fuel (producing the heat) and the coolant (transporting the heat to the power plant). There are many different types of MSRs, but the most talked about one is definitely the Liquid Fluoride Thorium Reactor (LFTR). This MSR has Thorium and Uranium dissolved in a fluoride salt and can get planet-scale amounts of energy out of our natural resources of Thorium minerals, much like a fast breeder can get large amounts of energy out of our Uranium minerals. There are also fast breeder fluoride MSRs that don’t use Th at all. And there are chloride salt based fast MSRs that are usually studied as nuclear waste-burners due to their extraordinary amount of very fast neutrons.

BOOK ON MOLTEN SALT REACTORS Thomas J. Dolan (Nuclear, Plasma, and Radiological Engineering Department, University of Illinois, Urbana); Thorium Energy Conference 15

About 40 international authors are writing an 800 page book on Molten Salt Reactors. There are 25 chapters grouped in four main sections: Motivation, Technical Issues, Reactor Designs, and Global Activities and Issues. First drafts of most chapters have been received, and experts will review them this fall.
This book, written in cooperation with the International Thorium Molten-Salt Forum, will provide a comprehensive reference on the status of molten salt reactor (MSR) research as of 2015. MSRs could operate safely at atmospheric pressure and high temperature, yielding efficient electrical power generation, desalination, actinide incineration, hydrogen production, and other industrial heat applications. In some versions on-line fuel processing could adjust the fuel composition continuously. The book should be useful for nuclear researchers, industrial engineers, university faculty and students, and and leaders of industry and government who want to understand the advantages of this promising energy source. Many chapters will involve collaboration of several authors.
The schedule is to have most draft chapters by the end of September, 2015; to review and improve them in October-December; and to publish the book in 2016. This book should raise awareness of MSR research as an important field, worthy of public and industrial support. Experts from India and other countries will be welcome to review chapters and to suggest improvements.

MSFR - Bibliography Laboratory of Subatomic Physics & Cosmology, IN2P3 (CNRS), Université Grenoble Alpes

Bibliography of work on Molten Salt Fast Reactors

2017 PLATTS NUCLEAR ENERGY CONFERENCE Kirk Sorensen; Energy from Thorium; 13 Feb 2017

I was asked to speak at the Platts Nuclear Energy Conference in Washington, DC, on February 10, as part of their panel on “New Approaches to Advanced Reactor Design.”
discusses waste management, and presents graphic illustrating differences in neutron spectrum and fuel types of molten salt reactors current being proposed/developed


Oak Ridge National Labs - Molten Salt Reactor Experiment

MSRE: Alvin Weinberg's Molten Salt Reactor Experiment "Th" Thorium Documentary; 30 Mar 2016

Oak Ridge National Laboratory was the home of Alvin Weinberg's Molten Salt Reactor Experiment. The MSRE proved that a fission reaction in molten fluoride salts could be contained in Hastelloy-N, and that a molten salt fueled reactor concept was viable. Two prototype molten salt reactors were successfully designed, constructed and operated at ORNL. The Aircraft Reactor Experiment in 1954 and Molten-Salt Reactor Experiment 1965-1969. Both used liquid fluoride fuel salts. The MSRE demonstrated fueling with U-233 and U-235. Alvin Weinberg was removed from his post and the MSR program closed down in the early 1970s. Aircraft Reactor Experiment & Molten Salt Reactor Experiment remain the only molten salt reactors ever operated.
mixes historic footage of the MSRE with video of Kirk Sorensen, Briony Worthington etc visiting ORNL and talking to engineers involved with the early work


The Molten-Salt Reactor Experiment Oak Ridge National Laboratory; YouTube; 14 Oct 2016

This film was produced in 1969 by Oak Ridge National Laboratory for the United States Atomic Energy Commission to inform the public regarding the history, technology, and milestones of the Molten Salt Reactor Experiment (MSRE). Oak Ridge National Laboratory's Molten Salt Reactor Experiment was designed to assess the viability of liquid fuel reactor technologies for use in commercial power generation. It operated from January 1965 through December 1969, logging more than 13,000 hours at full power during its four-year run. The MSRE was designated a nuclear historic landmark in 1994.

CLASSIC ORNL MSRE FILM KIRK SORENSEN; Energy from Thorium; 16 Oct 2016

Transcript of film

Robert Hargraves - The Energy Collective

Energy Cost Innovation, Part 1: Liquid Fuel Nuclear Reactors Robert Hargraves; The Energy Collective; 26 Aug 2013

Overview of reactor technologies especially aqueous and molten salt types, Aircraft Reactor, Thorium, MSR vs LMFBR, politics etc

Energy Cost Innovation, Part 2 Robert Hargraves; The Energy Collective; 27 Aug 2013

costs and features

Energy Cost Innovation, Part 3: Global Impact of Low-Cost Clean Energy Robert Hargraves; The Energy Collective; 28 Aug 2013

value of energy to deelopment, global warming, synthetic fuels, EROI, MSR development

EPD (Energy Process Developments) study

Feasibility of Developing a Pilot Scale Molten Salt Reactor in the UK

Six different reactor options were assessed in the MSR review:

  • Flibe Energy’s Liquid Fluoride Thorium Reactor (LFTR),
  • Martingale’s ThorCon,
  • Moltex Energy’s Stable Salt Reactor
  • Seaborg Technologies – Seaborg Waste Burner
  • Terrestrial Energy’s Integral MSR
  • Transatomic Power Reactor

The Weinberg Foundation's article: A Comprehensive Molten Salt Reactor Review has some well-informed discussion in the comments.

6 Nuclear Energy Companies Building Molten Salt Reactors

  • Terrestrial Energy
  • Moltex
  • ThorCon
  • Terrapower
  • Flibe Energy
  • Transatomic Power

MOLTEN SALT REACTORS - SAFETY OPTIONS GALORE Charles Barton / Nuclear Green Revolution

post of paper by Uri Gat of Oak Ridge National Laboratory & H. L. Dodds of University of Tennessee at Knoxville

Europe’s expertise in nuclear science and engineering will take thorium technology forward, John Laurie Copenhagen Atomics blog

This is part 2 of our conversation with John Laurie, author of the biggest blog on thorium energy in France.
Thorium, MSR

Charles Barton's commentaries

The Big Lots Reactor Revisited Charles Barton; Nuclear Green Revolution; 30 Jul 2010

Barton suggests building cheaper molten salt reactors using cheaper but less durable steel materials, but compensating for their reduced power*lifetime factors by operating in variable, load following, power cycles

What Are The Problems With LFTR Technology? Charles Barton; The Energy Collective; 29 Aug 2011

What are the problems with MSR/LFTR technology? This turns out to be a hard question to answer. Since there are a large number of LFTR design options, however, it is difficult to identify a set of problems that shared all of the options. Rather we should talk about elective choices, and the problems that a MSR/LFTR designer would face if a certain option were chosen.
  • 23 Apr 2016
I have reached the point at which I an conceive of future Nuclear Green Posts, I lack the where with all to do the research and generte written text. There are still important topics that no one is writing about. And unless the solid moderator problem is solved, we need to consider the possibility of FLiBe moderated epithermal MSRs. The choice of FLiBe will have some interesting consequences. It will limut the amount of of Plutonium that rhe Carrier/coolant/moderator salt can can carry. It will also lead to the production of a large amount of Tritium, which will have to be removed from core salts. The epithermal FLiBe moderated MSR Would seem to work best as a LFT, but it is not clear to me if it would work best as a burner or as a breeder. This would probably be a question for Mark Massie, or David LeBlanc to look at in their free time.
Another question would be alternative means of U-233 production. Those means would include thorium breeders as well thoriumtarget in a proton spilator. A floride carrier salt (again quite possibly FLiBe) could be used to carrie thorium in a blanket of a fusion reactor. As my father long ago suggested FLiBe could be used to capture heat from neutrons produced by thefusion process, and with aq FLiBe blanket, carrying thorium is a doable proposition. Just ask Ralph Moir. Thus by adding a molten salt blanket fussion can lead to heat capture as well as U-233 breeding. This makes fusion quite a bargan.
There are still stories to be told about molten salts with or without thorium.
  • unknown date
What are the disadvantages of the TAP reactor? The TAP Reactor is a medium size reactor. Unfortunately the Current concept, requires considerable field construction as opposed to factory construction. One of the major advantages of small modular reactors is that more construction can be expected to take place in factories. It is highly desirable that the entire project can be shipped to the field by truck, rail or barge, and assembled in a relatively short period of time. The reactor and its attendant facilities can be housed in prefabricated structures, that can be quickly assembled. If these structures are assymbled underground, they do not have to be massive, since rock and or soil will protect the reactor cor from attacks by aircraft or high explosives. Factpory construction of major parts in a small reactor can be accomplished through far more efficient use of lower cost labor than would be possible in a field construction environment. Thus it is highly desirable to limit feield labor as much as possible. It is notr clear what would be the optimal size for alow cost and quickly assembyles MSR, but the 3 year construction time suggested for the TAP reactor would far too long.
It might be that the 500 MWe size of the TAP reactor is an optimal size for the fuel efficiency that TAP desires. If so, it might be worth while for TAP to devote the same ingenuous attention to the manufacture of the TAP reactor, as they have devoted to their core design. The goal of increasing manufacturing efficiency is every bit as desirable as improving the efficiency of the nuclear process is.
  • 24 Mar 2016
I have noted before that there is considerable controversy related to the Transatomic Power's plan to use Zirconium hydride alloy as a MSR moderator. The hope is that Zirconium hydride will prove a more satisfactory moderator than Graphite. Under radiation, Graphite shrinks and then swells. Unfortunately the geometric changes make graphite an unsatisfactory moderator as it ages. Zirconium hydride was originally intended to serve as a moderator that was launched into space. Later it was used in reactorsa that were designed for student use. In that role, Zirconium hydride has proven satisfactory. Massie and Dewan believe that Zirconium Hydride, together with appropriate cladding, will prove a satisfactory moderator for a Middle size Molten Salt Reactor. Yet their life expectancy of the Zirconium hydride moderator is from 4 years to an almost indefinate period. A 4 year moderator life span would be very unsatisfactory, and might jepordize the TAP Reactor marketability. In addition, other MSR advocates have raised questions about the stability of the TAP reactor core. The latest TAP Technical White Paper includes a discussion of Zarconium-hydride moderator.
What are the disadvantages of the TAP reactor? The TAP Reactor is a medium size reactor. Unfortunately the Current concept, requires considerable field construction as opposed to factory construction. One of the major advantages of small modular reactors is that more construction can be expected to take place in factories. It is highly desirable that the entire project can be shipped to the field by truck, rail or barge, and assembled in a relatively short period of time. The reactor and its attendant facilities can be housed in prefabricated structures, that can be quickly assembled. If these structures are assymbled underground, they do not have to be massive, since rock and or soil will protect the reactor cor from attacks by aircraft or high explosives. Factpory construction of major parts in a small reactor can be accomplished through far more efficient use of lower cost labor than would be possible in a field construction environment. Thus it is highly desirable to limit feield labor as much as possible. It is notr clear what would be the optimal size for alow cost and quickly assembyles MSR, but the 3 year construction time suggested for the TAP reactor would far too long.
It might be that the 500 MWe size of the TAP reactor is an optimal size for the fuel efficiency that TAP desires. If so, it might be worth while for TAP to devote the same ingenuous attention to the manufacture of the TAP reactor, as they have devoted to their core design. The goal of increasing manufacturing efficiency is every bit as desirable as improving the efficiency of the nuclear process is.
Every month or two, I look at the Transatomic Power Internet page to see what TAP is doing and saying. My latest exploration has revealed a revised White Paper dated January 2016. This document is well worth exploring. Clearly TAP has been looking carefully at its design, and the latest statemebnts yield some interesting insights into their progress. First, They now seem very confident in their Zarconium Hydride moderator, which the white Paper states will occupie less space than a Graphite moderator would require.
If the TAP reactor can fulfill the clames being made with increasing confidence by the latest TAP White Paper, it could very well prove to be a revolutionary reactor design, even by the already revolutionary standards of Molten Salt Reactors. Look for the DOWNLOAD OUR WHITEPAPER button on the TAP page.

Transatomic Power

Terrestrial Energy - DMSR

French CNRS Molten Salt Fast Reactor

Molten Salt Reactor

The concept of Molten Salt Fast Reactor (MSFR): Molten Salt Reactor with a Fast Neutron Spectrum operated in the Thorium fuel cycle
The CNRS has been involved in molten salt reactors since 1997. Starting from the Molten Salt Breeder Reactor project of Oak-Ridge, an innovative concept called Molten Salt Fast Reactor or MSFR has been proposed, resulting from extensive parametric studies in which various core arrangements, reprocessing performances and salt compositions were investigated to adapt the reactor in the framework of the deployment of a thorium based reactor fleet on a worldwide scale (see next paragraph below). The primary feature of the MSFR concept is the removal of the graphite moderator from the core (graphite-free core), resulting in a breeder reactor with a fast neutron spectrum and operated in the Thorium fuel cycle. MSFR has been recognized as a long term alternative to solid fuelled fast neutron systems with unique potential (negative safety coefficients, smaller fissile inventory, easy in-service inspection, simplified fuel cycle…) and has thus been selected for further studies by the Generation IV International Forum in 2008.
In the MSFR, the liquid fuel processing is part of the reactor where a small side stream of the molten salt is processed for fission product removal and then returned to the reactor. This is fundamentally different from a solid fuel reactor where separate facilities produce the solid fuel and process the Spent Nuclear Fuel. Because of this design characteristic, the MSFR can thus operate with widely varying fuel composition. Thanks to this fuel composition flexibility, the MSFR concept may use as initial fissile load, 233U or enriched (between 5% and 30%) uranium or also the transuranic elements currently produced by PWRs in the world.

Molten Chloride Fast Reactor

Southern Company Awarded Up To $40M From DOE

Fast Reactors Using Molten Chloride Salts as Fuel M. Taube; Swiss Federal Institute for Reactor Research; Jan 1978

Report dealing with "a rather exotic "paper reactor" in which the fuel is in the form of molten chlorides" in four different (though all fast breeder) configurations.

Sherrell Greene on Liquid Chloride Reactors, "Business as Usual," and a second Manhattan Project Charles Barton; Nuclear Green Revolution; 19 Nov 2011

The third part of my interview Q&A with Sherrell Green focused on questions concerning the future of nuclear technology. My father had been a pioneer in research on Liquid Chloride Reactor technology in the 1950's. Sherrell Greene mention LCR development during out preinterview, so I wanted to ask him some follow up questions. The LCR is a potential competitor to the Liquid Metal Fast Breeder Reactor, but it is not clear if itsadvantages would out wight its potential costs.

LFTR: Liquid Fluoride Thorium Reactor

LFTR: A Long-Term Energy Solution? (Victor Stenger; HuffPo; 1 Sep 2012)

Seaborg Wasteburner

Seaborg Wasteburner Molten Salt Reactor whitepaper

ThorCon IMSR

Moltex / Stable Salt Reactor

Transmutation / waste burning

MOLTEN SALT REACTORS FOR BURNING DISMANTLED WEAPONS FUEL URI GAT and J. R., ENGEL Oak Ridge National Laboratory, H. L. DODDS University of Tennessee / Nuclear Engineering Department; 28 May 1992

The molten salt reactor (MSR) option for burning fissile fuel from dismantled weapons is examined. It is concluded that MSRS are potentially suitable for beneficial utilization of the dismantled fuel. The MSRs have the flexibilify to utilize any fissile fuel in continuous operation with no special modifications, as demonstrated in the Molten Salt Reactor Experiment, while maintaining their economy, The MSRS further require a minimum of special fuel preparation and can tolerate denaturing and dilution of the fuel. Fuel Shipments can be arbitrarily small, which may reduce the risk of diversion. The MSRS have inherent safety features that make them acceptable and attractive. They can burn a fuel type completely and convert it to other fuels. The MSRs also have the potential for burning the actinides and delivering the waste in an optimal form, thus contributing to the solution of one of the major remaining problems for deployment of nuclear power.

TRANSMUTATION CAPABILITY OF ONCE-THROUGH CRITICAL OR SUB-CRITICAL MOLTEN-SALT REACTORS Elena Rodriguez-Vieitez, Micah D Lowenthal, Ehud Greenspan, Joonhong Ahn; Conference: “Actinide and Fission Product Partitioning and Transmutation”; 2002

A neutronic parametric study is performed for graphite-moderated molten-salt (MS) critical or source-driven sub-critical transmuting reactors. The NaF-ZrF 4 MS reactor is fuelled with transuranium isotopes from LWR spent fuel and operates in a once-through mode. The MS with actinides is continuously fed and continuously extracted at a very slow rate. All the fission products are removed from the core as soon as formed. The primary question addressed is whether or not it is possible to design such a reactor to have an acceptable k eff when at equilibrium composition, while the Ac concentration is below their solubility limit, and what is the corresponding transmutation fraction. The primary design variables are the MS channel diameter and the graphite-to-MS volume ratio (C/MS). For an average power density of 390 W/cm 3 of MS, MS feed rate of 1 millilitre/day/MW th and actinide concentration of 12.87 mol% it was found that both k eff and the fractional transmutation peak while the equilibrium concentration is at a minimum when C/MS is close to 1.0. The equilibrium actinide concentration is below the solubility limit for C/MS between 1 and 7 for 7cm and 3.5 cm channel diameter and between 1 and 15 for a 1 cm channel diameter. The peak k eff is close to 1.0 and the fractional transmutation exceeds 90% in one pass through the core. The Pu coming out from the C/MS=12 core has a very low fissile content of only 17%. The optimal core has an epithermal spectrum and small channel diameter. The graphite lifetime in the core is 0.6 or 1.3 years for C/MS of 1 or 3, respectively. Reduction of the power density to 39 W/cm 3 can increase the graphite lifetime by an order of magnitude. This reduction of the power density reduces the attainable k eff by ~5% and increases the equilibrium actinide concentration by ~0.4 mol%. An illustrative core design for a 10 GW th MS transmuter is given.

UCB Fluoride Salt Cooled High Temperature Reactor

Pebble Bed / Molten Salt / Brayton cycle

Mk1 PB-FHR Technology Berkeley Nuclear Engineering

The Mark 1 Pebble-Bed FHR (Mk1 PB-FHR) pre-conceptual design is the latest in a series of studies to explore potential designs for fluoride salt cooled, high temperature reactors. The Mk1 design effort established four major goals, aimed at exploring further the potential benefits provided by FHR technology:
1) To evaluate how FHRs might be coupled to air Brayton combined-cycle power conversion, currently the dominant technology for new fossil power plants;
2) To provide a detailed design for a passive decay heat removal system, to enable improved safety studies for FHRs;
3) To develop a credible design for an annular FHR pebble-bed core, based upon earlier UCB work on the use of pebble fuels in FHRs, and
4) To evaluate how modular construction methods could be applied to FHRs, keeping all components inside the size range that is rail-shippable and utilizing the same steel-plate composite modular construction methods applied in the Westinghouse AP1000 reactor design.
The new Mk1 design, completed in September 2014, builds upon earlier pre-conceptual design studies. This design further increases confidence that FHRs can be designed to have high intrinsic safety, and that with their higher temperatures FHRs can provide more flexible and valuable services than current reactor technologies.
The result of the Mk1 pre-conceptual design study is a 236-MWth Mk1 PB-FHR that uses a General Electric (GE) 7FB gas turbine, modified to introduce external heating and one stage of reheat, in a combined-cycle configuration to produce 100 MWe under base-load operation, and with natural-gas co-firing to rapidly boost the net power output to 242 MWe to provide peaking power. As with previous FHR pre-conceptual designs cited above, the Mk1 design is also documented in a new UCBTH report (Report UCBTH-14-002), published at the end of September, 2014.

The UCB Mk1 design has been spun-off into a company - Kairos Power


Kairos Power’s reactor technology uses a novel combination of existing technologies to achieve new levels of economy, safety, flexibility, modularity and security for nuclear power production. These technology choices were driven by a desire for the Kairos Power design to be economically competitive, safe, and optimized to interface with an increasingly intermittent and unpredictable grid. Kairos Power builds upon major strategic investments that the U.S. Department of Energy has made to support development of advanced reactors.
  • High temperature fuels for helium reactors
  • Chemically inert and transparent coolants for molten salt reactors
  • Flexible power conversion technology for natural gas combined cycle plants
  • Passive safety systems for advanced light water reactors
  • Low pressure structural materials for sodium reactors
Kairos Power’s reactor uses fully ceramic fuel, which maintains structural integrity even at extremely high temperatures. This fuel will be undamaged to well above the melting temperatures of conventional metallic reactor fuels. Proven methods for fabricating and testing these fuels have been demonstrated at U.S. National Laboratories. By using pebble-type fuel, Kairos Power reactors can refuel on line, enabling exceptional reliability and availability.
Kairos Power’s reactor uses molten fluoride salt coolant. Molten fluoride salts have outstanding capability to transfer heat at high temperature, excellent chemical stability, and the ability to retain radioactive fission products that might be released from fuel. Extensive experience and design information exists from the early U.S. reactor development program that studied and tested liquid-fueled molten salt reactors. These studies confirmed the compatibility of these salts with Kairos Power’s high-temperature structural materials, enabling commercially attractive reliability and service life.
Kairos Power’s reactor uses a nuclear air combined cycle (NACC) to enable highly flexible and responsive electricity generation. Kairos Power’s NACC technology benefits from the large supply chain that exists for natural gas combined cycle plants with unique capabilities afforded by the nuclear heat source. By co-firing with natural gas or hydrogen, Kairos Power’s NACC technology can deliver high-ramp-rate and efficient peaking power to enable high-renewable-energy (thus high-intermittence) grid operation while simultaneously providing clean baseload generation. No existing generating technology can match the combination of efficiency and flexibility that can be achieved with NACC.
Passive safety means that Kairos Power reactors do not require electricity to remove heat from the core after shutting down. Kairos Power reactors have uniquely large safety margins based on the selected combination of fuel and coolant, which allows emergency cooling to be driven by fundamental physics rather than engineered systems. In Kairos Power’s reactor, there is no need to provide for make-up coolant (since the coolant cannot boil away), and the fuel tolerance for extremely high temperatures allows orders of magnitude more cooling capability under accident scenarios compared to water-cooled reactors. High-temperature fuel and coolant dramatically simplifies emergency cooling under all conceivable accidents.
The intrinsic low pressure in Kairos Power reactors enhances safety and eliminates the need for bulky and expensive high-pressure containment structures. Kairos Power technology leverages key U.S. federal investments in design, structural materials, and components for low-pressure pool-type reactors, including critical updates to the ASME Boiler and Pressure Vessel Code for design at our service conditions.
No. While the use of thorium in a breeding reactor provides potentially attractive benefits, the current challenges with baseload generation do not stem from the price or availability of uranium. Using high-temperature fuels and fluoride salt coolants simplifies licensing, operation, and corrosion control of Kairos Power reactors, while maintaining all relevant safety aspects of molten-salt-fueled reactors.

Chinese Academy of Sciences

China spending US$3.3 billion on molten salt nuclear reactors for faster aircraft carriers and in flying drones Brian Wang; Next Big Future; 6 Dec 2017

China will spend 22 billion yuan (US$3.3 billion) on two prototype molten salt nuclear reactors.
Two molten salt nuclear reactors will be built in the Gobi Desert in northern China.
  • Molten salt reactors can produce one thousandth of the radioactive waste of existing nuclear reactors because of deep burn. More complete conversion of the nuclear fuel.
  • Molten salt reactors can have designs that are proof against nuclear meltdowns
  • The chinese reactors could use thorium. China has some of the world’s largest reserves of the thorium metal.
The Chinese project has been funded by the central government and the two reactors are to be built at Wuwei in Gansu province, according to a statement on the website of the Chinese Academy of Sciences. The lead scientist on the project is Jiang Mianheng – the son of the former Chinese president Jiang Zemin – and it is hoped the reactors will be up and running by 2020.

High Temperature Gas-cooled / Pebble Bed Reactors


HTR-10 Wikipedia

China plans to open 1st ‘meltdown-free’ nuclear power plant by 2017 Chinese High Temperature Pebble Bed Reactor

China Could Have a Meltdown-Proof Nuclear Reactor Next Year Richard Martin; MIT Technology Review; 11 Feb 2016

Two high-temperature, gas-cooled reactors under construction in Shandong will make up the first commercial-scale plant of its type in the world.
In what would be a milestone for advanced nuclear power, China’s Nuclear Engineering Construction Corporation plans to start up a high-temperature, gas-cooled pebble-bed nuclear plant next year in Shandong province, south of Beijing. The twin 105-megawatt reactors—so-called Generation IV reactors that would be immune to meltdown—would be the first of their type built at commercial scale in the world.
Construction of the plant is nearly complete, and the next 18 months will be spent installing the reactor components, running tests, and loading the fuel before the reactors go critical in November 2017, said Zhang Zuoyi, director of the Institute of Nuclear and New Energy Technology, a division of Tsinghua University that has developed the technology over the last decade and a half, in an interview at the institute’s campus 30 miles south of Beijing. If it’s successful, Shandong plant would generate a total of 210 megawatts and will be followed by a 600-megawatt facility in Jiangxi province. Beyond that, China plans to sell these reactors internationally; in January, Chinese president Xi Jinping signed an agreement with King Salman bin Abdulaziz to construct a high-temperature gas-cooled reactor in Saudi Arabia.

China's HTGR fuel production line starts up World Nuclear News; 29 Mar 2016

A pilot production line of fuel elements for China's Shidaowan HTR-PM - a high-temperature gas-cooled reactor (HTGR) demonstration project - has started in Baotou, Inner Mongolia. The first tank of uranium dioxide powder was slowly poured into the dissolution tank on 27 March, marking formal entry into production of the HTGR fuel line, China National Nuclear Corporation announced the following day. Earlier this month, the National Nuclear Security Administration approved an operating licence for the fuel production line. The production line will have an annual capacity of 300,000 spherical fuel elements. The National Nuclear Security Administration issued a permit for its construction in February 2013 and an opening ceremony was held the following month. The installation of equipment was completed in September 2014.

Progress Report on HTGR reactors in China and U.S. 9 Neutron Bytes; Apr 2016

Development of the a high temperature gas cooled reactor (HTGR), a concept with more than three decades of history behind it, in 2016 has had several new breakout milestones in China and the U.S.
  • In March 2016 China installed the first of two reactor pressure vessels for a demonstration high temperature, gas cooled (HTGR) (Pebble Bed) reactor that is under construction at Shidaowan in Shandong province.
  • In January 2016 the U.S. Department of Energy announced that X-energy, located in the Maryland suburbs of Washington, DC, has won a $40 million grant to develop the Xe-100 pebble bed High Temperature Gas-Cooled reactor (HTGR). The development grant includes $6M in FY2016, which will be supplemented with additional investor funding from X-energy.
  • The Next Generation Nuclear Plant alliance (NGNP) continues its work on development of the Areva Antares HTGR, a prismatic block design. The NGNP alliance has published a business plan with the objective of building a prototype at the U.S. site in the 2020s.

Will China convert existing coal plants to nuclear using HTR-PM reactors? Rod Adams; Atomic Insigts; 21 Nov 2016

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 downwind of the coal stations.
Converting coal-burning supercritical steam plants to nuclear power plants by replacing the furnaces and boilers with high temperature gas cooled reactors might become a routine power plant improvement in the relatively near future. The High Temperature Reactor – Power Module (HTR-PM) project is aimed at demonstrating the feasibility of this evolutionary concept.
At the recent High Temperature Reactor 2016 (HTR2016), held in Las Vegas, NV, Prof. Zhang Zuoyi, Director of China’s Institute of Nuclear and New Energy Technologies (INET), briefed his colleagues in the international community of high temperature gas reactor enthusiasts on the current status of the HTR-PM. That project is one of the more intriguing clean air projects underway in the world today.

China Advances HTGR Technology Abby L. Harvey; Power; 1 Nov 2017

China’s State Nuclear Power Technology Corp. (SNPTC) has completed the installation of its high-temperature gas-cooled reactor (HTGR) project, the joint venture told the International Atomic Energy Agency (IAEA).

NGNP Alliance




Meet A Startup Making A New Kind Of Safer, Smaller Nuclear Reactor X-energy PBR

Nuclear batteries

Scientists are turning nuclear waste into super-efficient diamond batteries PETER DOCKRILL; Science Alert; 29 NOV 2016

Scott's team has so far demonstrated a prototype diamond battery that uses an unstable isotope of nickel (nickel–63) as its radiation source. Nickel 63 has a half-life of approximately 100 years, meaning the researchers' prototype device would still hold about 50 percent of its 'charge' in 100 years' time.
But the scientists say there's an even better source they could work with – and doing so would end up providing a solution for the UK's massive stockpiles of nuclear waste. The first generation of Magnox nuclear reactors in the UK produced during the 1950s through to the 1970s used graphite blocks to help sustain the nuclear reactions, but the technique comes at a cost. During the process, the graphite blocks themselves become radioactive, generating an unstable carbon isotope, carbon–14. The last of these Magnox reactors was retired in 2015, but after decades of nuclear power generation, there's an awful lot of waste byproduct left over, with almost 95,000 tonnes of these graphite blocks needing to be safely stored and monitored while they remain radioactive. And that could be a pretty long time, given that carbon–14 has a half-life of about 5,730 years.
"Carbon–14 was chosen as a source material because it emits a short-range radiation, which is quickly absorbed by any solid material," says one of the researchers, Neil Fox. "This would make it dangerous to ingest or touch with your naked skin, but safely held within diamond, no short-range radiation can escape. In fact, diamond is the hardest substance known to man, there is literally nothing we could use that could offer more protection."
According to the researchers, carbon–14 batteries would only be good for low-power applications – but their endurance would be on a whole different scale. "An alkaline AA battery weighs about 20 grams, has an energy density storage rating of 700 Joules/gram, and [uses] up this energy if operated continuously for about 24 hours," Scott told Luke Dormehl at Digital Trends. "A diamond beta-battery containing 1 gram of C14 will deliver 15 Joules per day, and will continue to produce this level of output for 5,730 years — so its total energy storage rating is 2.7 TeraJ."

Fusion *


Carbon nanotubes shown to protect metals against radiation damage David Szondy; Gizmag; 5 Mar 2016

An international team of scientists led by MIT has discovered that adding small amounts of carbon nanotubes to metals makes them much more resistant to radiation damage. Though currently only proven in low-temperature metals like aluminum, the team says that the ability of the nanotubes to slow the breakdown process could improve the operating lifetimes of research and commercial reactors.