Radiation Protection Today Winter 2021 - Page 19

The state of play with fusion energy

Dr Thomas Davis is a nuclear engineer specialising in fusion technologies . He is President and Chief Technology Officer of Oxford Sigma .
For sustainable , non-carbon dioxide emitting , long-term energy production , nuclear fusion energy is widely perceived to be the ultimate terrestrial energy source . Nuclear fusion has the potential of producing near-limitless energy due to the abundance of necessary fuel with minimal resource use . The realisation of the gravity of climate change , and the need for low-carbon energy and electrical sources , have concentrated the attention of governments and private investors around the globe on the prospects of fusion energy .
Fusion is typically considered in the scientific community to enable a longer term , dense and stable energy source compared to fission energy . In addition to producing electricity , propulsion via fusion energy holds the potential to enable deep space travel . The major benefits of fusion energy compared to fission energy lie in its independence from reliance on special nuclear material , such as uranium or plutonium , zero production of high-level nuclear waste , and lack of a chain reaction , among others . Whilst these clearly demonstrate the most substantial benefits of fusion as a power source , significant technological , materials , and regulatory challenges remain which must be overcome before commercialisation can be realised .
As of today , governments are enabling and funding public fusion energy projects , such as the UK Atomic Energy Authority ( UKAEA ) whilst private fusion companies work towards commercialising fusion energy . Private fusion companies have received
Radiation Protection Today Winter 2021 nearly USD $ 1.9 billion of private funding to date as outlined in a report published by the Fusion Industry Association in October 2021 . The technologies that private fusion companies are attempting to commercialise range from magnetic- , magneto-inertial , and inertial-confinement fusion .
On the UK public fusion side , the government has invested £ 220 million into the UKAEA Spherical Tokamak for Energy Production ( STEP ), which will demonstrate the ability to generate net electricity from fusion . STEP will also determine how a magnetic confinement fusion plant will be maintained through its operational life and prove the potential for the plant to produce its own fuel . Across the pond , the US government has increased the options available to private fusion companies for collaborating with national laboratories in order to assist in raising the technology readiness level of various fusion specific technologies . This approach supports private fusion by accelerating the path towards commercialisation . Recent trends have seen a new private fusion company created every year , and they generally propose novel methods of fusion technology with the aim of fully commercialising fusion .
Design options for fusion reactors vary among private industry and public projects . Several prominently proposed fusion designs are based on the tokamak configuration . This design features a reactor chamber consisting of a vacuum vessel , in which the fusion fuel is situated in a plasma state at approximately a hundred million degrees centigrade . The fuel is generally deuterium and tritium ( with a 50 % ratio each ). Tritium has a 12.3-year halflife so must be bred online during the fusion reaction due to the quantities needed ( grams to kilograms ). The breeding is achieved by wrapping the tokamak device with a lithium-
6 3 4 containing blanket to enable the Li ( n , H ) He reaction . The tritium produced by breeding