Energy’s underdog gets a sustainable makeover

Grace Shih-Chia Tseng
Grace Shih-Chia Tseng

Updated technology in the field of ‘nuclear recycling’ may cast off the negative connotations that nuclear energy currently battles with

The awareness of fighting climate change is now, ever-present; our generation needs to find a sustainable energy supply that doesn’t further heat up the globe. Exploring renewable energy is one of the paths governments, investors and activists are taking – and nuclear energy, known for its near-zero greenhouse gas emissions, could just be the solution they have been looking for.

However, there is one major issue that nuclear power presents: unlike solar or hydropower, nuclear power has the potential to create radioactive and hazardous waste. The risks behind current nuclear waste reprocessing procedures have brought nuclear power’s stability into a topic of debate.

The fault behind the current issues with nuclear energy lies with uranium, a radioactive element used as fuel for nuclear fission reactors. Once nuclear reaction has occurred, the content of the fuel isn’t quite the same as when it was first loaded. The spent fuel, control rod, and even parts belonging to the reactor mechanism have all, more or less, become radioactive by the end of a reaction cycle. These radioactive substances are hazardous towards life forms; they disturb normal biological processes and thus need to be segregated in concrete walls.

By using depleted uranium as fuel for the vast majority of the nuclear core of a traveling wave reactor (TWR), we help consume what is currently considered a form of waste

Based on current reprocessing technologies, the choices to handling nuclear waste are either segregation or regeneration. Nuclear waste, although mostly stored, can regenerate power if technology allows. However, globally, nuclear waste is mostly kept in isolated storage. Natural decay of radioactive objects would take up thousands of years and thus neutralisation cannot be considered an effective solution.

The sheer amount of radioactive substance has already become a problem to many nations. Waste created in one place often needs to be shipped away to some other more remote areas for safer storage. There are in total 74,258 tonnes of nuclear waste in America, according to the Nuclear Energy Institute. The nation’s current biggest repository plan on the site of Yucca Mountain is estimated to store another 70,000 tonnes. A permanent solution other than storage is needed.

Solutions being deployed to address this issue could change nuclear power from an often-unpredictable energy source into a shining hope for the future.  New technology called nuclear recycling. One innovative company, TerraPower, has a new model of nuclear reactor that uses depleted uranium (U-238) as fuel. Roger Reynolds, senior technology advisor at TerraPower, says the company believes this new model can significantly reduce the need for enriched uranium at nuclear plants.

TerraPower nuclear energy
TerraPower has developed a new nuclear technology called the traveling wave reactor (TWR) that aims to mitigate many of the shortcomings of today’s nuclear energy technologies

“Depleted uranium currently is considered by the nuclear industry to be a waste byproduct of the uranium enrichment process. By using depleted uranium as fuel for the vast majority of the nuclear core of a traveling wave reactor (TWR), we help consume what is currently considered a form of waste,” he says.

Reynolds highlights the fact that this new reactor does not require any chemical separation of its used fuel, therefore freeing the industry from the problem imposed by today’s reprocessing technology. This innovation has been thought to be able to “greatly reduce the risk of weapons proliferation, as well as reducing waste,” he explains.  

The TerraPower’s innovative nuclear reactor consumes depleted uranium as fuel, and runs a longer life cycle than usual fast reactors. Adding the fact that it uses depleted uranium, U-238, an isotope that takes up 99.3 per cent of natural uranium, as well as being a sustainable part of what is normally considered waste. Using depleted uranium as fuel is a means of both recycling and reducing waste.

In business terms, at this stage TerraPower remains a private company and is not open to public investment. However, a list of early-stage partners including renowned names such as Bill Gates, Nathan Myhrvold, Charles River Ventures, and Khosla Ventures, says a great deal about their prospects. The leading business anticipates their impact to be a great one. Reynolds says the company expects future revenues from their service “when commercial plants of this type are built around the world”.