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By Charles Rhodes, P.Eng., Ph.D.

Most of the value of an electricity system lies in its capacity to sustainably supply dependable and CO2 emission free electric and thermal power. Nuclear power systems operate by transmuting nuclear fuel elements into reaction product elements where the average binding energy per nucleon in the reaction products is much larger than in the nuclear fuel elements. This change in average binding energy per nucleon becomes heat that is harvested by the coolant of a nuclear reactor.

Renewable energy may seem desirable but it lacks both dependability and thermal power capacity. In high latitiude countries, such as Canada and Russia, renewable electricity generation is both seasonal and intermittent and can provide at most only about 30% of the non-fossil energy required for fossil fuel displacement. The remaining 70% of the non-fossil energy required for fossil fuel displacement must come from dependable hydroelectric or nuclear power sources.

Dependable power sources are also required to black start and stabilize the public electricity grid.

With the exception of a few jurisdictions such as British Columbia, Quebec, Washington State and Norway that have both both plentiful hydroelectric power and the geography required for seasonal hydraulic energy storage, most jurisdictions must rely on nuclear electricity generation for dependable non-fossil electric power.

The electric power output from a fleet of nuclear power stations is much more dependable than the electric power output from a fleet of renewable generators because:
a) Nuclear generators have a capacity factor of about 90% as compared to an average renewable generator capacity factor of about 30%;
b) The failure modes of nuclear generators are statistically independent whereas renewable generators have common mode failures.

Shutdown of one nuclear generator in a fleet of such generators does not diminish the electric power output of the other nuclear generators whereas all the solar panels in a fleet stop producing electricity at night and all the wind generators in a fleet stop producing electricity during low wind periods.

Natural gas fuelled generators have a potential common mode failure related to the available natural gas pipeline pressure, which is a big problem in situations where electrically powered compressors are used maintain natural gas pipeline pressure. A sustained and widespread electricity grid failure can lead to loss of natural gas pipeline pressure. Absent liquid fuel backup it becomes impossible to black start the electricity grid using natural gas fueled combustion turbine based electricity generation. Due to lack of voltage source power inverters with surge capacity at existing distributed wind and solar generators it is also impossible to restart the public electricity grid using only wind and solar electricity generation.

A large fraction of present fossil fuel energy consumption is for production of heat. In urban markets it is more economic to provide dependable nuclear district heat via piped steam or hot water than to provide dependable heat from any form of clean electricity generation.

There are two methods of producing nuclear energy, fission of high atomic weight elements and fusion of low atomic weight elements. Both methods are explored in this web site section.
However, from a practical economic public power perspective nuclear energy released via fission of unstable heavy isotopes, that are bred from abundant more stable fertile heavy isotopes, is the only dependable, sustainable and economic source of clean power that can fully displace fossil fuels. A significant portion of the nuclear energy released must come from fast neutron induced fission to dispose of long lived nuclear waste and to sustain conversion of fertile isotopes into fissionable isotopes.

A 2013 overview of the various nuclear reactor technologies is contained in the text New Technologies Associated to the Construction of Nuclear Power Plants.

Public misconceptions about nuclear power are concisely addressed in a PragerU Video.

The status of civilian nuclear power in 2019 is summarized in Ensuring the Future of Nuclear Power.

The design of conventional light water cooled nuclear power reactors is summarized in the:
Nuclear Engineering Handbook

A technical overview of current nuclear power issues is presented in the draft text: A Nuclear Green New Deal by Darryl Siemer. This text provides the perspective of a retired senior Idaho National Laboratory scientist on the future of nuclear power.

A March 2021 report titled: "Advanced" Isn't Always Better by Edwin Lyman raises a number of important issues which must be addressed by proponents of the various advanced reactor technologies. An important responding document is a Letter from Dr. Alex Cannara.

Advances in Fast Neutron Reactor (FNR) technology have rendered obsolete past concerns about nuclear reactor safety and nuclear waste disposal. However, the present wasteful use of the limited supplies of the fissile isotopes U-235 and Pu-239 in unsustainable nuclear fuel cycles is an enormous concern. As fossil fuels are phased out the amount of available dependable power will be constrained by the available fissile isotope supplies. It will likely take at least a century to quadruple the fissile isotope inventory via fuel breeding.

A major problem today is that existing electricity markets reward nuclear reactor owners for low cost per kW output without taking into consideration long term fissile isotope supply sustainability. The existing water cooled nuclear reactor technology is not fuel sustainable and is rapidly depleting the natural fissile isotope resource.

Another concern is squandering of limited public resources on development of new nuclear reactor types that are not fissile isotope sustainable. It is imperative to apply the limited public resouces to deployment of liquid sodium cooled Fast Neutron Reactors (FNRs), because only liquid sodium cooled FNRs provide a proven technology that can sustainably fully displace fossil fuels.

Five further major benefits of liquid sodium cooled FNRs are:
1) Sodium is chemically long term high temperature compatible with other base metals (Fe, Ni, Cr, U, Pu, Mo) used for economic FNR fabrication;
2) The sodium cooled FNR fuel cycle can be configured to reduce long lived nuclear waste production more than 1000 fold as compared to existing water moderated reactors.
3) The use of sealed fuel tubes that permit almost all of the fuel reprocessing to be carried out at a shared remote facility instead of at each reactor site.
4) Future potential for up to 800 degree C operation using fuel tubes fabricated from molybdenum depleted in Mo-95.
5) Future potential for fuel extension using dedicated fuel tubes containing a mixture of ThCl4, KCl and LiCl where the Li is Li-7 and the Cl is Cl-37.

A major issue with liquid sodium cooled reactors is ensuring that the primary sodium never contacts air or water and that any secondary sodium fires remain small and inconsequential. To achieve this end each liquid sodium cooled reactor has multiple independent secondary heat transport systems.

Another class of potentially fuel sustainable nuclear reactors is molten salt cooled reactors fuelled by thorium, which is naturally about 4X more abundant than is uranium. Thorium fuelled reactors operating with a sustainable fuel cycle require continuous chemical processing of their blanket fuel to selectively remove protactinium. This selective protactinium removal is enabled by dissolving thorium in a molten salt coolant that can be continuously circulated for both chemical processing and heat removal.

The molten salt reactors can be further divided into chloride salt cooled fast neutron reactors with fuel tubes to maintain the core fuel geometry and fluoride salt cooled thermal neutron reactors that use a rigid moderator to maintain the core fuel geometry and hence can operate safely without fuel tubes.

Molten salt reactors superficially seem simple but they have numerous practical implementation problems primarily related to their higher temperature of operation, complex corrosion issues, moderator degradation and the sophisticated chemistry that must be implemented at each reactor site. The fluoride salt cooled reactors also have a safe power limitation related to the required minimum liquid fuel residency time inside the moderator assembly.

As of 2020 there are over 100 reactor-years of liquid sodium cooled nuclear reactor operating experience in several countries. The Russians have had a large size liquid sodium cooled power reactor program for many years. Their top of the line unit with significant operating history is the BN-800.The Chinese with Russian assistance have two liquid sodium cooled power reactors under construction with scheduled completion in 2023. There are no scientific or engineering constraints to almost immediate large scale deployment of liquid sodium cooled reactors operating with sustainable fuel cycles to meet the challenge of climate change.

By comparison there are only about 2 years (17,000 running hours) of fluoride salt cooled laboratory size reactor operating experience in North America and there is no operating experience with chloride salt cooled reactors. There are many unresolved material and radio chemistry issues with molten salt cooled reactors. The Chinese have had a large team of engineers working on molten salt reactor issues for over a decade. In spite of best intentions there is almost no possibility that molten salt cooled reactors operating with a sustainable fuel cycle can be scaled up and deployed sufficiently quickly to significantly impact climate change in the next few decades.

A major problem with reactor development in the USA is US governmental corruption by the US fossil fuel industry. The US Democratic party is unwilling to face the reality that in 1994, at a time when the USA led the world in liquid sodium cooled fast neutron reactor technology, then president Bill Clinton cancelled the entire multi-billion dollar program in favor of cheaper fossil fuels. The US Republican party has long been dominated by fossil fuel interests. Both parties have embraced a rigid nuclear regulatory regime that is focused on obsolete light water cooled reactors. The result is that China, Russia and India are now dominating the world nuclear power industry and in North America US companies are doing limited new reactor demonstration in Canada due to Canada's more flexible nuclear regulatory regime. Unlike the new Chinese and Russian sodium cooled power reactors, no new present US power reactor technology is capable of sustained displacement of fossil fuels.

Other than via renewable energy, fusion based electricity generation is difficult and expensive to realize on Earth. For fundamental thermodynamic efficiency reasons, as long as low cost fission fuels are available, the cost per kWhe of Earth based fusion energy production will always remain much higher than the cost per kWhe of Earth based fission energy production. The fundamental difficulty is that over half of the electricity generated by present fusion reactor technologies must be used to sustain the fusion reaction.

A possible avenue of future nuclear fusion fuel cost mitigation is mining He-3 from the surface of the moon. In theory it is possible to breed H-3 and hence He-3 in fusion reactors but sustaining the required controlled fusion reactions on Earth is extremely difficult. The problems include a low plasma density, a small fusion reaction cross section and large ongoing plasma energy loses via energetic neutron emission. The fusion reactor size required for a self sustaining fusion chain reaction with a reasonable net electric power output is believed to be too large for economic construction.

This web site section primarily focuses on liquid sodium cooled Fast Neutron Reactors (FNRs) fueled by U-238 bred into Pu-239/Pu-240 because this technology in combination with renewable energy generation provides the only viable way of sustainably and completely displacing fossil fuels during the next few decades while avoiding production of long lived nuclear waste. At some future date this technology will likely be supplemented by breeding Th-232 into U-233.

1. Nuclear Motivation 2. Nuclear Technologies
3. Sustainable Nuclear Power 4. Modular Reactors
5. Electricity Generation Reactors 6. Reactor Design Constraints
7. Integrated Zero Emission Energy Plan8. A Fresh Look at Nuclear Energy
9. Nuclear Now by Will Davis 10. We Need To Talk About Nuclear Power
11. Shellenberger Testimony Relating to Building More US
Civilian Nuclear Power Capacity, January 15, 2020
12. Argument for Simplification of NPP Regulation
13. Conference Presentation (30 minute) 14. Conference Short Presentation (20 minute)
15. Conference Short Presentation Slides 16. NOBODY'S FUEL video.
17. Wide Area Nuclear District Heating in Haiyang City, China 18. Fukushima Disinformation
19. How the LNT Model was Born and Sustained 20. MIT 2021 Future NP Slides
THE US Nuclear Industry as described by Michael Shellenberger and others in testimony to the US government and in a January 15, 2020 letter to US President Donald J. Trump.
World Wide Nuclear Power Summary, November 2018, by Prof. Igor Pioro
US Nuclear Program January 2019
Russian Nuclear Power Program 2018
Russian Sodium Cooled Reactors
Nuclear Power Plant Safety by Herschel Specter
Ed Calabrese lecture: On the effects of low-dose radiation and linear-no-threshold (LNT) hypothesis (55 minutes)
Unintended Consequences (of the Linear No Threshold Model) - The Lie That Killed Millions and Accelerated Climate Change
Pandora's Promise (1hr 26min) A movie in which leading enviromentalists conclude that humanity cannot survive without sustainable nuclear power.

The Need For Testing Advanced Nuclear Power
Powering Ontario
Indian Nuclear Energy Program
Nuclear Fuel Reprocessing at ORANO LA HAGUE
Current Status and Future Developments in Nuclear-Power Industry of the World
Current Status of Reactor Deployment and Small Modular Reactor Development in the World
Nuclear Energy Development in Ireland Dec. 2020
1. CANDU Reactors 2. Light Water Reactors
3. Small Modular Reactors 4. Advanced Reactor Evolution
5. Molten Salt Reactors 6. Fast Neutron Reactors - Overview
7. FNR Politics - Overview 8. FNR Fissile Dilema
9. FNR Concept - Overview 10. FNR Description - Overview
11. FNR Features - Overview 12. FNR Operation - Overview
13. FNR Fuel Cycle - Overview 14. FNR Initial Fuel Sources
15. Ottensmeyer Plan 16. Ottensmeyer Plan Detail
17. Ottensmeyer Plan Implementation 18. FNR Sodium
U-233 Production
19. FNR Material Recycling 20. Non-Proliferation
21. FNR Geometry 22. FNR Design
23. FNR Fuel Rods 24. FNR Fuel Tubes
25. FNR Fuel Tube Wear 26. FNR Fuel Bundle
27. FNR Core Zone Geometry 28. FNR Monitoring System
29. FNR Core 30. FNR Blanket
31. FNR Reactivity 32. FNR Temperature Setpoint
XX FNR Uniformity
33. FNR Mathematical Model 34. Liquid Sodium Guard Band
35. FNR Primary Sodium Pool 36. FNR Temperature Profile
FNR ASME Code Issues
37. FNR Primary Liquid Sodium Flow 38. FNR Secondary Sodium Heat Transport System
39. FNR Intermediate Heat Exchanger 40. FNR Induction Pump
41. FNR Steam Generator 42. FNR Enclosure
43. FNR Air Locks 44. FNR Indicator Tubes
45. FNR Open Steel Lattice 46.FNR Ultrasonic Imaging System
47. FNR Steam Turbine 48.FNR Electricity Generator
49. FNR Earthquake Protection 50. FNR Cooling Towers
51.FNR Facility 52. FNR Siting
53. FNR Prompt Neutron Pulse 54. FNR Control
55. FNR Safety 56. FNR Fire Suppression
57. FNR District Heating 58. FNR FINANCING
59. FNR Specification Summary 60. CO2, ENERGY AND POWER REALITIES
61. Energy Policy 62. Open Letter to G-20 Government Leaders
63. Ontario FNR Policy 64. Energy Ministry Priorities
65. Email to Canadian Minister of Natural Resources Seamus ORegan March 9, 2020 66. Reply from Canadian Minister of Natural Resources
Seamus ORegan to March 9, 2020 email
67. Federal 2021 Budget Input
1. Radiation Safety 2. Radiation Therapy
3. Nuclear Waste Categories 4. Used CANDU Fuel Bundle Handling
5. Nuclear Waste Disposal 6. Helium-3 Recovery
7. NWMO / OPG 8. Radio Isotope Dry Storage
9. Used Fuel Concentration 10.
11. Radio Isotope Containers 12. Porcelain
13. Radio Isotope Container Seals 14. Seepage
15. DGR Ventilation 16. Jersey Emerald
17. DGR Closing Remarks 18. Nuclear Waste Disposal Press Release
19. Nuclear Education 20. Presentation Notes
21. Pickering Advanced
Recycle Complex (PARC)
22. Letter To Federal Political Leaders
23. Letter to Minister of Environment
and Climate Change, Ontario
24. Letter to Mininster of Environment
and Climate Change, Canada
25. U of T 17-02-09 Slide Presentation 26. U of T Presentation
Fusion section is currently being reconstructed.
Please examine this section at a later date.
1. PIF Glossary 2. Nuclear Fusion Prospect
3. Plasma Impact Fusion 4. Nuclear Fusion Engineering Considerations
5. D-T Fusion Fuel 6. Spherical Compression Part A
7. Adiabatic Compression 8. Fusion Output
9. Liquid Lead Constraints 10. Spherical Compression Part B
11. Random Plasma Properties 12. PIF Process
13. Liquid Lead Shell Formation 14. Pressure Vessel
15. Port Valves 16. Process Timing
17. Tritium Breeding18.
19. Spheromak Compression 20. Real Plasma Spheromaks
21. Spheromak Generator 22. Plasma Spheromak Lifetime
23. Vacuum Pumping Constraints 24. Liquid Lead Pumping
1. Micro Fusion Introduction 2. Micro Fusion FAQ
3. Micro Fusion Energy Flows 4. Micro Fusion Economics
5. Micro Fusion Regulatory Hurdles 6. Alumina Cylinder
7. Micro Fusion International

It is the intent of this author to eventually produce web pages addressing all of the above mentioned topics.

This web page last updated July 19, 2021.

Home Energy Physics Nuclear Power Electricity Climate Change Lighting Control Contacts Links