V. CLOSED CYCLE REACTOR TECHNOLOGIES
Closed cycle reactors were much more complex to develop and have a chequered history. Most use a densely packed metallic fuel enriched to 20% of fissiles and cooled by liquid metals. The early designs were more difficult to control than PWRs so the research proceeded slowly and carefully. Slow progress left them open to budget cutters but 3 of these metal fuelled reactors are now ready for deployment, meeting the same stringent safety requirements as PWRS. There are now no technical reasons why the Closed cycle cannot be fully implemented to use the entire 23Mt of Uranium listed by the IAEA.
The UK was the first civilian programme to follow the Closed cycle with their MAGNOX reactors. The magnesium cladding for their fuel rods disintegrates after use, so the fuel had to be recycled. A mix of Plutonium isotopes, unsuitable for weapons, was recovered for eventual use in Fast Reactors, but they were cancelled. The UK was left with a stockpile of over 110 t of Plutonium fuel.
1. The Russian approach [RT, 2014] has not stumbled and the design of a big, commercial fast reactor, the BN-1200, cooled by liquid Sodium, is now being finalised. The special recycling methods required for fast reactor metallic fuels still need industrialisation with robotic handling. Each recycling plant will serve 50 reactors. Russia will recycle their old weapons Plutonium as fuel for their current BN-800 model.
2. The US Department of Energy has had a malign effect on closed cycle technology over the last 25 years. The Argonne National Laboratory was tasked with development of civilian reactors. ANL developed the “Integral Fast Reactor” and the recycling methods to the point of building a prototype. It met a sorry fate when USDoE suffocated it with bureaucratic incompetence. DoE decided to create all the facilities of the Closed cycle in a hugely expensive industrial network, like NASA’s, before building the prototype [Till & Chang, 2011]. The project cost soared, produced little, and was axed. ANL was reduced to a skeleton laboratory. GE-Hitachi have picked up the research and developed the commercially viable S-PRISM Fast Breeder Reactor [GE-Hitachi, 2014]. As DoE has lost interest, GE-Hitachi has set aside its offer to consume the US stocks of Spent fuel. Instead, they have proposed to build their first one in the UK to burn a fuel blend of the UK’s 110t Plutonium stockpile with DU , but bury the Spent fuel. The stockpile would be far better used to start a closed cycle UK fleet of S-PRISMs.
South Korea has a project, PRIDE [S. KOREA,2014], to industrialise the recycling, but the US opposed this (2011) on the grounds that it could lead to weapons proliferation and was close to North Korea. The position has now shifted to a USDoE agreement for S. Korea to be given all the recycling knowledge from ANL and to build the first Integral Fast Reactor. No such nuclear transfer or collaboration has ever been enacted with any other country. Why would the USDoE set up S. Korea as a competitor to GE-Hitachi? The US obsession with weapons proliferation dominates their thinking. Their ‘Swords to Ploughshares’ stunt purchased old weapons Plutonium from Russia to be burned in their Open cycle PWRs. None of the material has been processed and the special MOX fuel plant has been put on hold [CONGRESS,2014].
3. Fusion is the third fast reactor to consider. It fuses Deuterium and Tritium isotopes of Hydrogen to throw out a Helium nucleus and an ultra-fast neutron. Given the slow history of Fusion it seems counter-intuitive, but a small, 50MW Fusion core, surrounded by a molten Lithium Fluoride salt blanket with Depleted Uranium is a powerful breeder since a kilo of neutrons makes 239 kilos of Plutonium. The necessary Fusion technologies work today [Tokamak Energy UK, 2014], the separation of fuel from this molten salt is simple, so this is entirely feasible and could start to fill the gap by 2030. [McNamara 2008]. Fusion could use DU for direct Plutonium breeding and partner PWRs for many decades.
4. The magnificent concept of the Molten Salt Thorium Breeder Reactor was well tested at the USDoE Oak Ridge National Laboratory (ORNL) but never made it out. The molten salt mix, which is both fuel and coolant at 5% enrichment, is easier to handle than the solid PWR fuels. Its own Closed cycle allows for continual refuelling and waste removal as the salt is pumped around. This amazing reactor cannot melt or burn, is completely safe against loss of coolant and no reactor would be lost to an engineering fault. These reactors are still on the drawing board. China has a new laboratory of over 400 scientists working on a 25 year reactor and built-in reprocessing technologies programme. The project has now been accelerated to a 10 year time frame which could impact before 2050. [Xu, 2014]
Our guess at the order in which these contenders will get to market: RosAtom BN-1200, GE-Hitachi S-Prism, Small Fusion Breeder, Thorium breeder, but it is more like a steeplechase than a horse race.
The Closed cycle is a big winner in many ways:
3,500 reactors only needs a mix of 3,500t of mined Uranium and Thorium per year.
We have centuries to discover Uranium and Thorium resources.
The total nuclear energy footprint for the USA is a tiny 156 reactor sites, at 4 GW-e each, and 12 recycling plants.
Recycling the world’s 176,000t stock of Spent fuel will yield merely 1,000t of two radioactive wastes, Caesium and Strontium, needing storage for 500 years. The rest has many uses. [McNamara, 2013]
McNamara, Oct. 2013: 21st Century Spent Fuel Management:
RT 2014: Russia Today:
South Korea, 2014: WorldWideScience.org:
Till & Chang, 2011: ‘Plentiful Energy’,
Tokamak Energy 2014:
Xu Hongjie,China, 2013:
http://www.mashmedia.com/Chinese_Academy_ of_ Sciences Video 5.
MORE REACTOR DETAILS AT OUR NUCLEAR PRIMER ...
MORE DISCUSSION OF SMALL FUSION REACTORS HERE...
How do reactors produce a ‘mix’ of Plutonium isotopes and why is the mix not good for weapons?
When could Russia support the Closed cycle on a large scale?
Why would the UK use a fast reactor merely to ‘destroy’ a stockpile of mixed Plutonium isotopes?
Is peer-to-peer international collaboration a useful way to accelerate the arrival of the Closed cycle?
Has China scooped the pool on the Thorium molten salt breeder?
Why would Fusion need a PWR as a partner? Is it to swap Plutonium for Tritium