When Will Nuclear Go Green?: Why We Should Recycle Fuel Rods

December 19th, 2012 by Michael Morphew* Leave a reply »

This country has started to pay a lot of attention to solar, wind, and clean coal technologies.  But why does nuclear get shunned from the spotlight?

The United States gets 20 percent of its energy from nuclear power, third behind coal and natural gas. How many ads have you seen for “clean coal” or natural gas in the last year? But when was the last time anyone saw an ad on television for recycling nuclear fuel?

The most basic of environmental actions is recycling, but unlike other countries, we do not recycle our fuel rods. Instead of recycling the fuel rods, new material is mined, enriched, and used as fuel.

With a limited supply of natural resources, and the consumption of resources to store the used fuel, we need make this source of power more environmentally friendly. One of the most basic paths to reducing environmental impact is recycling.

I.  Why Recycle?

Nuclear reactors use only five percent of the fissionable material in a fuel rod. However, instead of putting that 95 percent to use generating power, the United States puts it in temporary storage. As of 2011, 65,000 metric tons of nuclear fuel rods are being stored in the U.S., almost all at the individual reactor sites.

If the technology exists and is safely being used by our international friends, and the U.S. thinks of itself as a world leader, why are we not recycling? It is estimated that if we recycled the fuel rods that are currently seen as waste, we would have enough energy to power the entire country for more than 12 years. That is a lot of fossil–free energy

Nuclear power is in use in over 30 countries. The technology to recycle nuclear fuel exists, and in use in six countries today – but not in the country that essentially started the nuclear field. France gets 78 percent of their power from nuclear energy. They recycle their fuel, are not in the news for nuclear incidents or security issues.

In the United Kingdom, it is a similar story. They get 19 percent of their power from nuclear energy and they recycle.

 

2.  The Opposition

Unfortunately, the nuclear industry suffers from a stigma in this country. Part of this stigma goes back to the fact that nuclear power was introduced to this country as a weapon – something to be feared. In many ways that fear persists today, and has hampered our implementation of newer technologies. Technology born in this country, and improved upon and implemented in other countries, should come home.

At one point, not recycling was a political decision. In 1976, the Federal government banned nuclear recycling. At that time, there was a national security concern involving nuclear energy. Considering the time – the cold war – it is understandable. The laws have since changed, but not the mindset. The country – the world – is going green, and it is time for our nuclear energy program to get with the times.

There are two major points of opposition to recycling spent fuel. The first is cost, and the second is security – specifically proliferation of plutonium. While both are legitimate concerns, their magnitude is not as significant as they claim to be.

There are some that argue that the cost of recycling nuclear fuel is too high. Then again, there are people that say the cost of alternative energy is too high. Yet, as a society, we have decided that the benefits of alternative energy outweigh the upfront costs of design and implementation, as well as the increased cost of the power.

But the government needs to help. Recently, the United States government spent $1.5 billion to support renewable energy, but spent over twice as much to support fossil fuels. If the government continues to favor fossil fuels, going green will be even harder.

The cost of designing, licensing, constructing/modifying, and operating a facility to recycle nuclear fuel rods is high. However, just like alternative energy, it is done for the greater good – to help the environment. Just like recycling of other products, there is less mining, transportation, and waste.

By lowering the amount of mining and waste, there is a benefit to society and the environment. That benefit is hard to put into dollars, yet we seen past that issue for solar and wind energy.

 

III.  The Technology

As with most things, there is more than one approach to nuclear recycling. One approach is to recycle the current stockpile of spent fuel. This is referred to as reprocessing, and is currently being done outside the U.S. using the PUREX process.

The second approach is a closed cycle reactor system. A closed cycle design incorporates recycling into the process so that the fuel is regenerated. This is a called a “breeder” reactor for its ability to create its own fuel.

 

A.  Reprocessing

The technology to reprocess spent nuclear fuel has been around for over 65 years. In 1960, the Atomic Energy Commission (predecessor of the U.S. Department of Energy) was granted U.S. Patent No. 2,924,506 (‘506 Patent) from an application filed in 1947.

The ’506 Patent is for an extraction process using a solvent–based solution to separate plutonium from an aqueous solution. In essence, the process separates usable materials from transuranic waste and other elements generated during nuclear fission so the usable materials can be reprocessed into new fuel rods.

Despite the fact that commercial reprocessing is not done in the United States, the DOE is funding work on technology related to reprocessing nuclear fuel. This work is typically done at the national laboratories, specifically Idaho National Laboratory, Oak Ridge National Lab, and Argonne National Laboratory. 

The ’506 Patent is just one of the 151 patents DOE has been granted since 1956 involving nuclear fuel reprocessing, for technologies range from the processes and chemical solutions, to the containers for the fuel rods.

The ‘506 patent is cited as prior art for three patents, two of which are important technological offshoots. In 1976, the United Kingdom Atomic Energy Authority was granted U.S. Patent No. 3,959,435 (‘435 Patent). This patent uses a nitric acid solution to reduce the mount of tributyl phosphate used in the PUREX process.

In 1984, Kernforschungszentrum Karlsruhe GmbH in Germany was granted U.S. Patent No. 4,442,071 (‘071 Patent). This innovation changes the PUREX process to utilize sulfuric acid. While these two variants of the PUREX process are not compatible, both have provided a basis for a significant number of future patents.

Battelle LLC, with DOE provided funding, recently filed U.S. Patent Application Publication No. 2011/0250108. This patent application claims the invention improves the reprocessing of fuel used in light water reactors by reducing the number of steps, making the process safer, and reducing cost.

There are modifications to the PUREX process designed for specific purposes. TRUEX is a modified PUREX process that removes transuranics (TRU) during reprocessing. This process was created in the U.S., and two of the patents came out of Argonne National Laboratory (U.S. Patent Nos. 4,548,790 and 4,574,072).

DIAMEX (DIAMideEXtraction) process uses different chemicals to avoid the creation of gases that could lead to acid rain. The DIAMEX process is a French innovation, and patented in the U.S. under U.S. Patent Nos. 4,572,802 and 4,938,871.

There is also SANEX (Selective ActiNide Extraction) (see, e.g., U.S. Patent Nos. 4,461,747, 4,867,951, and 5,256,383), which allows the separation of actinides and lanthanides in the PUREX process. There are no less than five other modified methods currently in use or under development.

Additional work is focused on the non–proliferation issue. To that end, modifications to the PUREX process are being tested that would prevent pure plutonium from being separated during reprocessing. One of these is called UREX (URranium EXtraction). UREX is designed to prevent plutonium from being extracted during reprocessing, and reduce the amount of waste requiring long–term storage.

Because some of these modifications only target one aspect of the PUREX process, they can be used together. For example, the UREX+ and UREX–1a processes each use four of the modifications, but the combinations are different.

U.S. Patent No. 7,854,907 is focused on targeting the separation of technetium during fuel reprocessing was granted in 2010. This process claims to be applicable to UREX and UREX+ reprocessing methods. Operators are able to adjust the PUREX process by combining the different modifications in order to achieve change the elements or combination of elements at the end of the process.

One of the most recent technological developments to the PUREX process comes from France. The process, named COEX™, was granted U.S. Patent No. 7,887,767 in the U.S. in 2011. This modification of the PUREX process keeps the plutonium with uranium together during the reprocessing, but allows uranium to be separated out. This addresses the non–proliferation concern. It also reduces the number of steps involved in reprocessing.

B.  Fast Reactors and Breeder Reactors

Fast reactors are a different type of nuclear reactor. Unlike most commercial reactors, a fast reactor does not slow fission neutrons. As a result, these neutrons cause more fission as they collide with fissile nuclei. The concept for fact reactors was patented in 1965 by U.S. Patent No. 3,212,982.

Breeder reactors are a type of fast reactor that can produce more fission material than they consume. Beloyarsk 3 in Russia is a BN–600 reactor, and is currently the only commercial fast reactor (but has not been used to breed fuel). These reactors used a liquid metal, liquid sodium, something that was covered by U.S. Patent No. 3,498,880 by the French Atomic Energy Commission in 1966.

When the reactor is set to match burning and production, it becomes a self-contained power generator. That means that over the operational life of the reactor, no new fuel need be brought in, and no waste would be removed from the site.

In the early 1980’s, Argonne West reconfigured the Experimental Breeder Reactor–II (EBR–II), and tested what is known as an Integral Fast Reactor (IFR). The IFR program combined different technologies, such as electrorefining, metallic fuel, a passive cooling system, and a sodium cooled reactor, to achieve the goal of eliminating the two biggest concerns regarding nuclear energy, proliferation of weapons grade materials and nuclear meltdown.

One of the technologies came from General Electric, which worked on the reactor design and obtained U.S. Patent No. 4,508,677 describing a small, modular reactor design.[1]

Safety is always a concern when it comes to nuclear power. As seen in Japan, loss of cooling to reactors is a major problem. The designers of IFR knew this, and set out to remedy the issue – and they did. The IFR passively shuts down when cooling is compromised.

The IFR was designed to solve the two major concerns of nuclear power, but the design is also important to recycling efforts. The IFR can use spent nuclear waste for fuel. Just as the IFR consumes transuranics in its own fuel, it can start the reaction process using transuranic elements in spent fuel from our current reactors. This provides an additional method of recycling the spent nuclear fuel we have now.

This also means that weapons grade material, such as plutonium from dismantled weapons, can be processed with other fuels in the reactor making them unusable for military applications. Because the IFR can be consumed, breed, or match burning and production, the reactor can be used for different purposes.

As a consumer, IFR can use the current spent fuel and military waste for fuel. There would be waste generated, but not like the spent fuel we have now. In order to prevent the proliferation of nuclear material, the IFR was designed to commingle elements, not separate or purify. The waste generated from an IFR reactor can be separated so that the actual “waste” volume is reduce, as well as the time need for safe storage.

The technology used to separate the plutonium with uranium from the waste is electrorefining. The process described in U.S. Patent No. 5,336,450 (’450 Patent) was designed to work with the IFR reactor.

One of the significant advancements over previous electrorefining methods, such as the “Process to Separate Transuranic Elements from Nuclear Waste” described in U.S. Patent No. 4,814,046, is that the ‘450 Patent process is a semi–continuous process as opposed to a batch process.

C.  The Future of IFR and Fast Reactors

General Electric is in the process of developing a reactor named PRISM (Power Reactor Innovative Small Module). The design underwent a pre–application review in the early 1990’s, and benefited the IFR program. PRISM is a sodium cooled, metal fuel design reactor very similar to IFR. This is because General Electric worked on the reactor design of the IFR project.

Also, the fuel for PRISM was tested as part of the IFR program. One of differences is that IFR uses a metal alloy fuel, and PRISM can use ceramic or metal fuel. In an effort to commercialize PRISM, GE’s small modular approach is designed to be scaled up by adding additional units, as described in U.S. Patent No. 6,185,269, and on GE’s website.

Fast breeder reactors, specifically the IFR, are not being commercially utilized in the United States, though interest, as well as research and advancements related to the technology continue.

Earlier this year, Sandia National Laboratory released a report considering licensing of sodium fast reactors, such as IFR. The report concluded there were two challenges regarding resurrecting the IFR project. The first is recovering the historical data from the project. The second is integrating the technological advancements to the components of the system.

One of the improved pieces is the electrorefiner used to separate uranium and other transuranic elements, specifically plutonium, from spent fuel. Argonne National Laboratory has continued to work on this technology since, and was granted U.S. Patent No. 8,097,142 in January 2012 for their most recent innovation. This technology continues to be important because non–proliferation is still a concern with reprocessing of spent fuel.

 

IV.  Conclusion

These technologies are moving forward, but our domestic implementation is lacking. Nuclear energy can be greener, and the technology exists to make it happen. Implementing these types of technologies will significantly reduce the amount of nuclear waste generated and stored.

Additionally, these technologies will minimize the environmental impact of the energy we consume by reducing mining, and the amount of carbon dioxide generated by fossil fuels. The merits of the technologies created and tested in the United States have been proven, and PUREX is in commercial use. The United States should tackle the challenge today instead of passing the burden to future generations. 

It is time to reduce our environmental impact, update our nuclear technology, and recycle our nuclear fuel.

 

*Michael Morphew is in his second year at Thomas Jefferson School of Law in San Diego.  He received his undergraduate degree in Business Administration from the University of Washington in Seattle.

This is the first of three posts highlighting work by students who took my seminar class - Green Technology, Climate Change, and Intellectual Property Law –  this semester at Thomas Jefferson School of Law.  – Ed.

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