This is where we hope we can answer any of the most common questions many people might have with regards to dealing with Recycling and the Disposition of Used Nuclear Fuel (UNF).
If you do not see a question you have and believe it should be included here, please email it to us. Also, if you feel you may care to discuss this please go to the Blog page and start the conversation!
Isn’t Used Nuclear Fuel recycling more expensive than current mining and enriching of uranium?
- With no other factors considered, the industry has taken the attitude that, yes, it is less expensive to mine and enrich, for almost 5 decades
- Only 5 % of uranium needed domestically is mined in the USA. President Trump recently stated he was going to put tariffs on imported uranium to encourage more domestic production. This was strongly opposed by the nuclear fuel production industry and he backed off. However, there are many other factors which must be considered:
- While uranium is currently plentiful and cheap, demands on uranium from an increasingly nuclear world outside the USA will undoubtedly put pressure on the availability and price of uranium.
- While MOX fuel manufacture in the USA has been a disaster economically in Savannah River, the French routinely make use of this mixture of uranium and plutonium to extract more energy from already mined uranium after it has been through one cycle in a reactor. If the French can do this, why can’t we?
- The fact that the USA is so far from independent in this important energy resource, the recycling of used fuel is necessary to recover the uranium since about 96% of the SNF inventory is uranium or plutonium and recovering this for use helps offset the domestic source of uranium for the future.
- While recycling may be more expensive than mining and enriching, it is not prohibitively so. It was the industry solution until the US Government mucked up the process by taking ownership of the Used/Spent Nuclear Fuel in the 1970's for proliferation fears. Maybe a combination of enriching and recycling will help the energy independence factor for uranium in the USA.
Is UNF dangerous?
- Like other toxic materials we deal with and ship every day, yes it is.
- However, there are factors to consider:
- UNF from the nuclear Navy has been routinely shipped to Idaho since the late 1950's with no incident.
- The containers necessary to protect from radiation during shipment are extremely robust physically simply because it takes a lot of steel and concrete to shield the radiation to make it transportable on the US highways within DOT regulations.
- It is NEVER shipped in a liquid state (no high level waste ever will be).
- The high profile of this material necessitates that it receive special attention when shipped. It will be escorted by SWAT teams, monitored remotely at all times, tracked from a central location and protected by on-call assets if any problems on the road were to exist.
- There have been tests on the shipment containers in “way beyond normal crash incidents” and in each case the container was not breached.
- The radiation signature of UNF decays very quickly and if the fission products can be removed (during a recycling process), the major radiation danger can be treated in a different manner and need only be sequestered for 300 years or so. In reality it loses its “lethal radioactivity” level of danger in much less time than that (less than 100 years), and is about 20% the volume of the original SNF assembly.
- Again, France has dealt with this for 6 decades with no incident, let alone any contamination or injury.
Isn’t plutonium a real problem to handle?
- Plutonium is most dangerous if inhaled. No transfer of plutonium is made in anything but a ceramic oxide form making it very unlikely that it would aerosolize.
- The shipping of plutonium is done by the DOE Office of Secure Transportation . These type of operations have been conducted since the 1950's with no incident. The security measures are far more rigorous than would be needed for UNF. The details are classified, but there has never been an incident in all the decades of shipping plutonium in the USA.
- Plutonium is never shipped in a configuration that can become a critical mass.
- As far as volume, a half a ton of plutonium will fit in a box 1 foot square (though it is not shipped like that).
How would recycling work for commercial Used Nuclear Fuel (UNF) in the United States?
- New fuel is not radioactive enough to require special handling requirements and stays in the reactor for about 3 years. It is moved to different positions in the reactor core to ensure an the fission process is the most efficient.
- When the fuel rods are used to the point where their effectiveness is no longer optimum, they are removed from the reactor using remote handling equipment and placed in pools of water so the tops of the fuel assemblies are about 30 feet below the surface of the water.
- In the United States, Used Nuclear Fuel spends 5-7 years in a pool of water that provides shielding for the radiation and cooling from the heat of decaying material.
- After its tenure in the cooling pool, the UNF has decayed enough that the heat can be removed by convection of air and no longer requires water to provide cooling.
- At this point, the fuel assemblies are placed in robust concrete “casks” for shielding and protection from the elements and stored in a configuration suitable for continued cooling until final disposition is possible. This is called “dry cask storage” and the UNF remains on each reactor site that produced it.
- If the decision is made to recycle UNF in the United States, the casks would be shipped to a central location into a configuration called “interim storage”. Ideally, this facility would be located adjacent to the recycling facility. They could stay in the same above-ground configuration as they were stored at each reactor site.
- The recycling facility would be designed to separate UNF into constituent chemical materials with the goal of being reused as much as possible. The manner in which it would be separated would depend on the reactor design that would accept the recycled fuel.
- When a fuel assembly is ready to be recycled, it enters the facility and is handled with remote handling equipment because it is still too radioactive to be directly handled.
- The first step is to remove the cladding material that surrounds each fuel pellet (about the size of an inch-long pencil eraser) and chop it into small pieces. This material is decontaminated and either reused or disposed as Low Level Waste.
- The ceramic fuel pellet is dissolved in nitric acid.
- Using a series of chemical operations, the material is separated into:
- Uranium (U)
- Transuranic elements (TRU)
- Plutonium (Pu) – There is a process to leave the plutonium with the TRU if that is desired
- Fission Products (FP)
- These materials can be used as follows:
- Uranium: can either be enriched and used as fuel or mixed with the Pu to make fuel called Mixed Oxide Fuel or MOX.
- Transuranic elements – These are materials heavier than Uranium that are made during the time the fuel assembly is in the reactor. They result from neutrons being absorbed into the nuclei of existing materials (mostly uranium) resulting in heavier atoms being formed, including elements of higher atomic number. These can be used in a reactor to produce energy or be disposed in the Waste Isolation Pilot Plant in New Mexico, whichever works out to be the most beneficial.
- Plutonium – This is a fissile radioisotope (meaning it can be directly undergo fission through absorption of a thermal neutron) and can be used to produce energy. In fact, as much as 40% (depending on how long the fuel is left in the reactor) of the energy that comes from a reactor is the result of Pu fissions.
- Fission Products – These are radioactive elements formed as a result of fission. They consist of many different isotopes, many of which are very radioactive. The energy of their gamma rays are high enough to penetrate the fuel assembly cladding with little loss of harmful potential. Although only 3% of used fuel is made up of these elements, the removal of these considerably reduce the potential danger of used nuclear fuel. The separation and disposition would require 300 years or less and take up a lot less volume than currently envisioned for all the UNF.
- The process is complicated, but has been done (and is being done) by France, England, Russia and Japan. China intends to recycle when they attain used fuel from their newly-built reactor fleet. The cost is substantial, but not daunting compared to the entire profit that can be realized from nuclear power. Finally, it was the way the spent nuclear fuel was to be treated before the US Government got in the way.
- Once separated, the products can be managed in many different ways based on the design of the fuel needed for either current reactors or future reactor designs.
Is transportation difficult or dangerous?
The short answer is no. Used Nuclear Fuel from the Navy reactors has been transported across the country for more than 5 decades without incident. The fuel assemblies must be robustly packaged in reinforced concrete and steel for shielding purposes. The final package must adhere to the Department of Transportation rules for any other shipment of radioactive material. The shipments will always have attendants and security guards with the material and will be remotely monitored every step of the way.
A lot of fear has been published about the damage to the environment or people if there were an accident. The material will NEVER be shipped as a liquid, let alone a liquid in a 55-gallon container. The “casks” are designed to withstand any railroad or highway accident completely intact. In fact tests have been made to ensure this is the case. Basically, if there is an accident, the cask will be picked up by a crane and placed on another trailer or rail car to continue its journey as before
Is there a terrorist danger?
There is always a terrorist danger, however, you must consider the nature of terrorist attacks and what their pattern of implementation has been. Used Nuclear Fuel (UNF) is dangerously radioactive if removed from its shielding container, so the simple act of getting to the material will be fatal. If this means nothing to the terrorist (likely), then the perpetrator must somehow convert the ceramic material into an aerosol to spread it as a Radioactive Dispersal Device (RDD). If a nuclear bomb is his intent, he must somehow change the chemical nature of the material using complicated dissolution methods and even more complicated extraction and production methods. Given the amount of security accompanying this material, it is extremely doubtful this could be done without being noticed. If you worry about taking this material to a remote location for these operations, bear in mind that a single cask will weigh upwards of 30 tons. Interdiction with this material is a very high risk operation with very low opportunity of success.
Terrorist events are usually very low risk operations with a very high opportunity of success, even if the success is minimally disruptive, so one the scale of what terrorists want, spent nuclear fuel is last on the list of likely targets. Terrorists are after headlines that throw, well, terror into the minds of their victims. The simple fact is that UNF is not at all a likely target for terrorists.
Why not leave the material on the nuclear reactor sites forever (or for a long time, at least)?
The truth is that the material stored on the sites is safe where it is. The degree of safety, however, is not the only consideration.
The fact is that only 5% of the energy potential is used in the fuel when it is time to remove it from the reactor. This is based on the design of the Light Water Reactors we use predominantly today. Remember, they are very profitable even at this low level of potential power usage. So, why would we want to ignore such a rich source of future carbon-free energy? When considering the damage to our environment, we are considering recycling of other commodities in a much more robust manner. It makes little sense to ignore the recycling of nuclear fuel and the least expensive way to do this is to move it to a central recycling location.
More importantly to utilities responsible for this material is the fact that the United States Government entered into an agreement to remove and dispose of the UNF through a program paid for by the nuclear power rate payers. They have forked over $40 billion dollars over the years. Even though some $15 billion has been spent, since the money is invested in US T-Bills, interest has been accruing and the total available is back over $40 billion now. The utilities have been economically damaged through a breach in a contract on the side of the United States. The courts have ruled in favor of the utilities and they are receiving about $2.2 million per day as a result of this breach ($750 million per year and rising). So, it is expensive to leave it where it is.
Finally, the people in the area surrounding a nuclear reactor become upset when a plant is closed and the economic benefit of the plant is gone, but the remains of the spent nuclear fuel stay in the local area. It is simply unethical to promise to take care of it and abandon that promise.