The Green Reactor: LFTR Green Engineering

The “green” status of nuclear power has been challenged because nuclear power allegedly does not conform to alleged Green principles; whether or not the supposed Green principles are in fact environmentally sound is of course open to question. The current post, however will not travel down that route, rather I intend to demonstrate that one form of nuclear reactor, the Liquid Fluoride Thorium Reactor, conforms to “green” standards.

The 12 Principles of Green Engineering are said to be:

Principle 1: Designers need to strive to ensure that all material and energy inputs and outputs are as inherently nonhazardous as possible.
Principle 2: It is better to prevent waste than to treat or clean up waste after it is formed.
Principle 3: Separation and purification operations should be designed to minimize energy consumption and materials use.
Principle 4: Products, processes, and systems should be designed to maximize mass, energy, space, and time efficiency.
Principle 5: Products, processes, and systems should be “output pulled” rather than “input pushed” through the use of energy and materials.
Principle 6: Embedded entropy and complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposition.
Principle 7: Targeted durability, not immortality, should be a design goal.
Principle 8: Design for unnecessary capacity or capability (e.g., “one size fits all”) solutions should be considered a design flaw.
Principle 9: Material diversity in multicomponent products should be minimized to promote disassembly and value retention.
Principle 10: Design of products, processes, and systems must include integration and interconnectivity with available energy and materials flows.
Principle 11: Products, processes, and systems should be designed for performance in a commercial “afterlife”.
Principle 12: Material and energy inputs should be renewable rather than depleting.

1: Designers need to strive to ensure that all material and energy inputs and outputs are as inherently nonhazardous as possible.
Materials inputs into the structure of the LFTR, its fuel and carrier salts, are not highly hazardous. The reactor can be built from a variety of materials, and a variety fluoride salts can be used as carrier salts. Most of the hazards of LFTR are internal to its operation, and can be controlled through the application of the principles of containment barriers to the design of LFTRs and their housing facilities. Containment barriers will protect the biological environment, by preventing accidentally released hazardous materials from reaching it. The LFTR makes little to no intrusion on the landscape. There need be no tall towers associated with the siting of LFTRs as there is with windmills,. Indeed LFTRs can be sited underground or underwater and thus have absolutely no undesirable aesthetic aspects. Unlike “green” windmills, LFTRs can be built to be wildlife safe. Unlike huge solar or wind arrays, LFTRs use little space, and thus are far less likely to have unintended negative consequences for local ecology.

2: It is better to prevent waste than to treat or clean up waste after it is formed.
The material outputs from the fission process in the LFTR can be inputs into industrial processes, or can be used in medicine, agriculture, food preservation, and sanitation. Heat not lost to the second law of thermodynamics can be put to a variety of uses. All long lived hazardous materials can be recycled as fuel in LFTRs until they are completely dissipated.

Principle 3: Separation and purification operations should be designed to minimize energy consumption and materials use.
Proposed fission product separation and extraction technologies are energy efficient and they would be operated either continuously or periodically as part of the reactor system. Extraction and purification systems are understood to be a vital and required part of LFTR design.

Principle 4: Products, processes, and systems should be designed to maximize mass, energy, space, and time efficiency.
The LFTR is outstanding performance in its minimization of mass, energy, space and time efficiency:
* The structure of the LFTR requires less material per kW of electrical output than conventional reactors.
* The LFTR requites fewer materials inputs per KW of rated electrical output than solar or wind generating system.
* The fuel and coolant inputs into the LFTR are tiny compared to conventional nuclear power plants. The LFTR can be air cooled, eliminating water use.
* The EROEI of the LFTR is potentially superior to the EROEI of not only Light Water Reactors, but also wind generators, and all forms of solar electrical generators. The EROEI superiority is at least two orders of magnitude.
* The LFTR is smaller than Light Water Reactors and its gas turbines are also smaller the steam turbines of LWRs. Since the LFTR produces a small percentage of the radioactive byproduct produced by the LWR, far less space needs to be devoted to the storageof radioactive fission products.
* Not only is the energy density of LFTR is superior to conventional LWRs, but is superior by several order of magnitude to either solar generation or wind generation systems.
* The LFTR produces as much energy per unit of time as the LWR, and it produces far more electricity per unit of time than solar or wind generation systems with comparable output ratings.

Principle 5: Products, processes, and systems should be “output pulled” rather than “input pushed” through the use of energy and materials.
The LFTR potentially has a materials, and energy output to input ratio to any other electrical generation system. Virtually 100% of the fuel input into the generation process is potential useful output. The EROEI of the LFTR is far superior to any “renewable” generating system.

Principle 6: Embedded entropy and complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposition.
The energy input into recycling, reuse, or beneficial disposition of reactor materials and fission products is a far smaller fraction of total electrical output than is the case with either conventional LWRs or “renewable” electrical generation sources. Heat not lost to the second law of thermodynamics can be recaptured for space heating, water heating, low temperature industrial process, and desalinization.

Principle 7: Targeted durability, not immortality, should be a design goal.

Nearly 100% of the fuel input into the LFTR is recyclable. The extraction and separation of many recyclable materials is part of the basic LFTR technology. Carrier salts can be reused. Materials used in the construction of the reactor are recyclable.

Principle 8: Design for unnecessary capacity or capability (e.g., “one size fits all”) solutions should be considered a design flaw.
The LFTR has outstanding potential for modular design. Factory production of small 100 MW to 300 MW LFTRs, and the clustering of several small LFTRs allow for the production of large amounts of electricity without the enormous capital investment required for both large conventional reactors and large renewable power generating projects.

Principle 9: Material diversity in multicomponent products should be minimized to promote disasse
mbly and value retention.

A high degree of materials standardization is possible with the LFTR. The LFTR can easily be designed to facilitate decommissioning, and the recycling of parts.

Principle 10: Design of products, processes, and systems must include integration and interconnectivity with available energy and materials flows.
The LFTR is unique among reactors in that its system is designed to facilitate the integration and interconnectivity of energy and materials flows. In this regard it shows superior qualities to renewable electrical generators and conventional reactors. It possess the ability to respond instantaneously to electrical load demand, and can serve as back up generating capacity.

Principle 11: Products, processes, and systems should be designed for performance in a commercial “afterlife”.
In this regard the LFTR is far superior to the LWR and superior to renewable power generation systems. Not only does the LFTR produce far fewer materials outputs than the LWR, but its materials outputs can either be safely recycled as useful and even valuable materials, or have value in medicine, industry, food processing, agriculture, and sanitation because of their radioactive properties. Waste heat from electrical generation with LFTRs can be reused for space or water heating, or in desalinization.

Principle 12: Material and energy inputs should be renewable rather than depleting.

All materials use in electrical production are either present in the earths crust in such large amounts that they cannot be depleted given the efficiency of the LFTR or are indefinitely recyclable. The amount of recoverable thorium in the earths crust greatly exceeds the amount that would be to produce all human energy till the time that solar evolution destroys the potential of earth to sustain human life. Thus the capacity of LFTRs to produce massive amounts of energy is indefinitely sustainable in cosmic terms, and has equivalent sustainability to other renewable electrical generating systems.

It is clear that not only is does the LFTR meet the requirements for green engineering, but far surpasses many of the “green engineering” characteristics of other renewable electrical sources. It possesses superior EROEI to all other renewable electrical generating systems. The LFTR makes more efficient use of all of its inputs compared to both LWRs and other “renewable” electrical generating systems, and the use of its outputs is only limited by the laws of nature.

In addition to the supposed principles of “green engineering” noted here, the LFTR has other “green engineering” characteristics.

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