The MBIR is a sodium-cooled fast reactor with 150 megawatts of thermal power and will have a design life of up to 50 years. It will be a multi-loop research reactor capable of testing lead, lead-bismuth and gas coolants, and running on MOX (mixed uranium and plutonium oxide) fuel.
NIIAR intends to set up on-site closed fuel cycle facilities for the MBIR, using
pyrochemical reprocessing it has developed at pilot scale
. This reprocessing could eliminate most nuclear waste and enable reuse as fuel.
They can close the fuel cycle with the reactor and new pyroprocessing. Closing the fuel cycle means all of the waste is converted back into usable fuel.
AEM-Technology started the manufacture of the reactor pressure vessel for MBIR in March, 2017 and has said that construction of the demonstration reactor should be completed by 2020. The project is expected to cost 16.4 billion rubles ($454 million). The MBIR will be the most powerful research reactor in the world.
What is a Fast Neutron?
Nuclear waste is mostly even-numbered Uranium isotopes. Uranium 238 can be converted to plutonium for fuel.
0.7% of natural uranium is ‘fissile’. This is odd numbered uranium isotopes.
It is mainly the ratio of Uranium 235 versus Uranium 238.
A thermal neutron is a free neutron with a kinetic energy of about 0.025 electron volts with a speed of 2.2 km per second.
A fast neutron is a free neutron with and 1 Megaelectron volt with a speed over 14,000 km per second.
Hit Uranium 238 with a fast neutron and you have a good chance can get Plutonium 239.
Enriched uranium gets the uranium 235 from 0.7% to 5% or more. Highly enriched goes higher. 90% enrichment is bomb grade.
There are probabilities and nuclear physics.
The uranium 238 and the Plutonium can be used in fast neutron reactors and new molten salt nuclear reactors and they can generate energy. The Uranium 238 in a fast reactor has about the same energy as Uranium 235 in most of the current reactors. The Russians have operated fast reactors commercially for decades. The French ran a fast reactor for a while as well. China is building some.
There are several companies making molten salt nuclear reactors. There was a 10 megawatt thermal molten salt reactor operated in the 1960s. These reactors are not as useful for generating nuclear bombs. Molten salt reactors can use up almost all of the uranium and plutonium.
If you use the neutrons in the right way or use advanced chemistry the uranium and plutonium in what is called nuclear waste can be used as nuclear fuel.
Pyroprocessing is a chemical approach.
Processing used fuel is the same as processing the concentrate of any metal mineral to recover the valued metals contained in it. Here the ‘ore’ (or effectively the concentrate from it) is hard ceramic uranium oxide with an array of other elements (about 4% in total), including both fission products and actinides formed in the reactor.
There are three broad kinds of metallurgical treatment at metal smelters and refineries:
* Pyrometallugy using heat to initiate separation of the metals from their mineral concentrate (e.g. copper smelting to produce blister copper, lead smelting).
* Electrometallurgy using electric current to separate the metals (e.g. alumina smelting to produce aluminium).
* Hydrometallurgy using aqueous solutions that dissolve the metal, with sometimes also electrolytic cells to separate them (e.g. zinc production, copper refining).
There are advanced chemistry facilities for recycling the fuel. This is called reprocessing. There are several ways to do it and they are expensive. Less than 10% of the waste fuel is sent through reprocessing. It is done mainly in France.
World Uranium Usage
The uranium that we use for all of our nuclear plants is about 65,000 tons per year. This is about 10% of world electricity. 40% of world electricity is from coal. The word uses 7.3 billion tons of coal per year. We use over 100,000 times more coal for 4 times as much power. The coal is burned and puts three times as much CO2 into the air. The burning adds two oxygens to the carbon. There are a hundred millions of tons of ash, soot and particulates. The small particulates get into the lungs and cause lung disease and heart disease. This contributes to the early death of 4 million people per year.
The uranium “waste” sits in cooling tanks for a few years and can be placed into metal boxes with walls that have neutron-absorbing boron.
After 5 years they can put into dry casks. Large-cement and steel barrels. Each one holds 10–15 tons of spent fuel. They are separated for safety reasons.
Each nuclear plants have several square miles of space. They have a lot of land for security and other reasons. If you packed the spent fuel close together then you can stack up a year’s worth on a basketball court. Uranium is denser than lead.
If you left the unburned fuel at each plant where they are currently located then in a few decades the number of molten salt reactors could be built up to use a lot of the fuel. Is there some new reactor going to come along and get all of the CO2 from coal out of the air? Or the soot and particulates out of peoples lungs? How about bringing the 4 million people per year killed early back to life?
4 million people seems like a lot. What does that number mean and how do we get to it. The air pollution in China, India and some other places is like smoking 6 cigarettes a day. What happens when you make babies, old people, asthmatics smoke 6 cigarettes a day every day?
4 million a year is close to the combat deaths for a year in World War 2. An air pollution world war that has never ended.
China has long-range planning and they plan to close their nuclear fuel cycle around 2050. It is a choice based upon economics and world uranium supplies.
The long-term solution is to store the waste on-site in dry casks with some separation and ramp up the construction of fast reactors or molten salt reactors and use all of the uranium 238 and plutonium to power the world for about 20 times longer than the 5% of the uranium (the 235 part) in the fuel rods that were already used.
What is left is stuff with short half-lives of 12 years or less. This material also is useful.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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