Nuclear Power Plants - 2024

 Nuclear Power Plants generate electricity without producing CO2 the dominant Greenhouse Gas (GHG.) This article explains the current process used to generate electricity in the 429 nuclear power plants in the world. Then it relates the new design for Nuclear Power plants now under construction.

 https://constructiondigital.com/articles/bechtel-launches-carbon-free-nuclear-power-plant

The nuclear power plants of the world today and in the near future all depend upon nuclear fission; specifically the fission of Uranium 235 under controlled conditions to prevent the "run-away reaction" called a melt-down. Control is typically supplied in modern fission plants by a computer-based digital control system. So far only one such plant has failed to prevent melt-down: the plant at Fukushima, Japan following a 9.1 magnitude earthquake and a 30 foot high tsunami that flooded the basement where the reactor water circulation pumps were located. While the plant was designed to withstand earthquakes, the flood caused by the tsunami caused failure of the cooling water pumps and an explosion of hydrogen gas accumulated at the reactors. Both the Chernobyl and 3-mile island nuclear power plant failures were due to inadequate control systems installed before computers were applied to control.

Modern pressurized water nuclear reactors use purified water to cool the reactor core and provide absorption of excess neutrons called moderation. The fuel consists of stainless steel rods that contain uranium 238 and are "enriched" with uranium 239. Control rods are also stainless steel but filled with Boron that can absorb excess neutrons and thereby reduce the rate of the reaction of uranium 239 that splits into smaller (less atomic weight) elements and releases neutrons that continue the chain reaction. Some of the released neutrons also convert the uranium 238 to plutonium 239; a byproduct of the fission reaction that occurs in this pressurized water fast breeder nuclear reactor.

The primary product of nuclear fusion is heat that passes into the cooling water, and then is exchanged with fresh water to generate steam that powers electric generators. Reactor cooling water is flittered and recycled through heat exchangers that produce the steam to power the electric generators. Generally, the steam condensate that is produced after powering the generators is cooled in the cooling towers that often identify a nuclear power plant. The steam condensate is not radioactive.

All modern nuclear reactors are controlled by a digital control system that looks much like a modern high reliability DCS used in process control. Many of the components are redundant to assure high availability. Often the entire control center has a duplicate off-site to be used in case a radiation leak forces abandonment of the human operators from the control center. All communications is redundant secure and highly available. Lessons learned at Fukushima require cooling water pumps, primary and backup, to be located above the maximum flood level for the area.

The "fast breeder" term is used because the Plutonium 239 that is produced in the nuclear reaction is later recycled into new fuel rods, since Plutonium 238 is also a fissionable material. The lower molecular weight byproducts of fission are less than 10 percent of the original fuel and are encased in glass and stored for future disposal. Fortunately the most radioactive byproducts are small in volume and are not a serious problem. It should be noted that fast breeder nuclear power reactors can be scaled and are the primary power source for all modern submarines and naval vessels.

Nuclear technology is not classified as secrete or proprietary. There are hundreds of textbooks of information about safe design of nuclear power plants.Yet the publicity of power plant failures at Chernobyl, 3-mile island, and Fukushima and the 1950 movie "China Syndrome" have strongly and in my opinion, wrongly biased public opinion negatively about nuclear power. It produces electric power at lower cost than any fossil fueled power plant, and does not generate or use any greenhouse gases.

Possible Future of Nuclear Power

Without much effort, the technology used to produce small nuclear power plants for US military/naval vessels can be used to build new smaller and lower cost nuclear power plants at any location with access to fresh water. Desalinization as used on shipboard could extend this to seaside installations.

Understandably, the public has an unfounded fear of nuclear power from the few accidents that have occurred. We have learned and compensated for those early failures so now plants cannot experience a core melt-down. But melt-down is the primary source of fear of nuclear power.

To remove the fear of melt-down, several new process for the reactor portion of nuclear power has been created:

a) Liquid sodium cooled reactor

Here is a description of Liquid Sodium Cooled nuclear reactors created by AI:

A liquid sodium cooled fast reactor (SFR) is a type of nuclear reactor that uses liquid sodium as a coolant instead of water. SFRs are considered a promising candidate for next generation nuclear technologies. Some of their features include: 

• Fast neutron spectrum: Neutrons can cause fission without being slowed down first, which could allow SFRs to use both fissile material and spent fuel from current reactors. 
• High power density: SFRs can achieve high power density with low coolant volume fraction. 
• High thermal efficiency: SFRs have high thermal efficiency. 
• Closed fuel cycle: SFRs have a closed fuel cycle. 

Some other features of SFRs include: 

• Oxygen-free environment: The oxygen-free environment prevents corrosion. 
• Sealed coolant system: Sodium reacts chemically with air and water, so SFRs require a sealed coolant system. 
• Special precautions: Sodium is chemically reactive, so special precautions are required to prevent and suppress fires. 

Some disadvantages of liquid metal cooled reactors include: Difficulties associated with inspection and repair, Fire hazard risk for alkali metals, Corrosion, and Production of radioactive activation products.

b) Liquid salt nuclear reactor

Here is a summary of information gathered by AI on the topic of a "Molten Salt Nuclear Reactor:

A liquid salt nuclear reactor, also known as a molten salt reactor (MSR), is a type of nuclear power reactor that uses molten salts to cool its core and produce electricity. MSRs are similar to conventional reactors, but they use salts instead of water to cool the core, which may make them more efficient and better suited for non-electric applications. 

MSRs can use molten salts as both a coolant and a fuel. In some designs, the fuel is dissolved in the molten salt-based coolant, while others use solid fuel rods with the molten salts only acting as a coolant. MSRs can operate at higher temperatures and for longer periods of time than other reactor types, and they can also be designed to operate in low-pressure environments. 

MSRs have several potential advantages, including: 

• No solid fuel

  Some designs don't require solid fuel, which eliminates the need to manufacture and dispose of it. 
• Nuclear waste burners

  MSRs can be designed to burn nuclear waste. 
• Safety

  MSRs have low excess reactivity, a negative temperature coefficient of reactivity, and low pressure, which can help keep things stable. The fuel salt is also generally not very reactive with the environment. 

• Corrosion

  Over time, alloys that don't dissolve in molten salt can form a protective coating that slows corrosion. 

c) Thorium fueled nuclear reactor

Here is a discussion about Thorium-fueled nuclear reactors gathered using AI:

Thorium-fueled nuclear reactors have several advantages over uranium-fueled reactors, including: 

• Abundance

  Thorium is three times more abundant than uranium. 
• Environmental impact

  Thorium-fueled reactors produce less long-lived nuclear waste than uranium-fueled reactors. They also don't emit greenhouse gases while operating. 
• Safety

  Thorium-fueled reactors have safety features that reduce the risk of nuclear accidents and proliferation. 
• Weaponization potential

  Thorium-fueled reactors have a lower potential for weaponization than uranium-fueled reactors. 
• Location

  Thorium-fueled reactors can be installed in remote and arid regions, far from coastlines and watercourses. 
• Efficiency

  Molten salt reactors (MSRs) that use thorium as fuel are highly efficient. MSRs use a suspension of molten salts instead of solid fuel rods to drive the chain reaction. 

However, there are some challenges to thorium-fueled reactors, including: 

• Extraction costs: Thorium is expensive to extract, despite its abundance.