By Charles F. Moreira
China plans to develop a plant to extract uranium from seawater to overcome her reliance on imports of uranium and other energy sources such as oil and natural gas, which risk supply being disrupted by her enemies in times of geopolitical tensions and conflict.
The demonstration plant would start production no later than 2035, though the uranium it produces is was likely to be more expensive than what nuclear power plants could afford to pay.
However, the official timeline for commercial production aims for 2050, with the arrival of fusion nuclear technology, according to Que Weimin, secretary general of the China Seawater Uranium Extraction Technology Innovation Alliance in a recent article in the China Nuclear Industry magazine.
As an industrial powerhouse with the world’s largest population and one of the fastest growing economies, China has an unquenchable need for energy, yet she has small oil and natural gas reserves and only 170,000 tonnes of uranium reserves which is less that France.
At the same time China is under pressure especially from the United States to cut her carbon emissions, with a goal to reach peak emissions by 2030 and to reduce emissions to be carbon neutral by 2060.
Whilst China has also been building large solar and wind farms, however energy generated from renewable sources such as hydropower, wind, solar, biofuels and other renewable sources such as geothermal, biomass and waste energy, together comprised 4,986 terawatt-hours in 2019, according to the BP Statistical Review of World Energy, or just over 12.6% of the total of 36,361 terawatt-hours generated that year from all sources. Amongst them, nuclear power generated only 823 terawatt-hours, whilst coal generated the lion’s share of 22,687 terawatt-hours, followed by 7,752 terawatt-hours from oil and 3,073 terawatt-hours from gas.
Also, wind and solar electricity generation are not consistent, so, to achieve this goal, China has turned to ramping up its nuclear power generation capacity and is building between six and eight new nuclear power stations per annum, such as its home-grown Hualong One technology reactors we featured in our previous article.
However, at this rate, China would need 35,000 tonnes of uranium per year by 2035, according to official estimates, which means that her uranium reserves would be depleted within five years, according to the South China Morning Post of 13 May 2021.
Right now, more than 70% of China’s uranium supply comes from some of the largest mines in Canada and Australia, both of which are close allies to the United States, and China’s diplomatic relations with these two countries are rather rocky right now.
Over the past 10 years, China has invested in uranium mines in Niger, Namibia, Kazakhstan, Uzbekistan and Canada, but these existing supplies are not enough to meet the growing domestic demand, even though around 50 reactors are currently operational and 17 more under construction.
So to ensure its nuclear energy security, China must find sources which are independent of other countries, so has turned to extracting uranium from the sea.
Not exactly new
However, the technology to extract uranium from the oceans is not new, though costs per kilogramme of uranium extracted has so far been high compared to mined uranium, even though there is 1,000 times more uranium in the sea than in mines.
In the academic paper, A Review of Uranium Extraction from Seawater: Recent International R & D by Nor Azillah Fatimah O., Jamaliah S., Siti Fatahiyah M. of the Radiation Processing Technology Division, Malaysian Nuclear Agency who wrote:-
“Despite the very low uranium concentration (3.3 parts per billion)in seawater, it’s total amount reaches 4 X 1012 kg, that is equivalent to 1000 times of the mine uranium. To recover an economically significant quantity of uranium from seawater, an adsorption method using a suitable solid adsorbent seems to be feasible with regard to economical and environmental impacts.”
“Extensive investigations of adsorbents capable of recovering uranium from seawater and aqueous systems have been carried out during the last two decades especially in Japan Atomic Energy Agency, Japan but until now, this method is not feasible for mass production. In this paper, recent international activities are summarised, on both the laboratory scale experiments and large scale marine experiments. R & D opportunities are discussed for improving the system performance and making the collection of uranium from seawater more economically competitive.”
According to the authors, the first study on the extraction of uranium from seawater was carried out by Great Britain in 1953, with research activities on the extraction of uranium from seawater having been reported in several European countries, including Finland, France, Germany, Greece, Italy, Poland, and Sweden.
Japan had shown amongst the greatest commitment to research efforts to extract uranium from seawater with the first studies by the Japan Tobacco and Salt Corporation in the 1960s, and the Japan government began a research programme to extract uranium from seawater in 1974.
Many government sponsored research and development (R&D) activities were carried out in the 1970s and 1980s. However, most of the studies were subsequently suspended due to low recovery efficiency and modest uranium market prices.
Recent studies conducted by Japanese Atomic Energy Agency (JAEA) has prepared a pre-irradiation fibrous amidoxime-based adsorbent for uranium extraction from seawater and carried out the marine experiment to evaluate the uranium collection from seawater.
In 1999, a new 3-year effort was initiated to start the marine experiments of the mass produced adsorbent fabric materials. A stack design with a floating frame and cage of adsorption beds was placed about 7-kilometre offshore of Aomori, Japan.
However, the costs associated with the floating frame and cage in the stack design represented approximately 80% of the collection cost. Therefore, a new collection system for cost reduction by using a braid type adsorbent was developed later in the marine testing.
Meanwhile, recently extensive work has been carried out by Bhabha Atomic Research Centre (BARC), Mumbai, India by two groups – the Radiochemistry Division and the Desalination Division.
Their studies focused on the amidoxime based adsorbent systems, in the forms of membranes or hydrogels. Other systems with resin or magnetic particles grafted with ligands (such as amidoxime or calixarene) were also studied.
“Activities for extracting uranium from seawater began in China during 1970’s and are still active until now. However, most of the work focused on evaluating absorbents and understanding the kinetics and mechanism of absorption. Jin et al. reported that hydrous titanium oxide, aluminum hydroxide, and organic resins were among the absorbents tested in late 1970’s – early 1980’s, meanwhile more recent studies were evaluating polyacrylamidoxime and chitin for the extraction of uranium from seawater”, the authors wrote.
Back to the South China Morning Post, the uranium in seawater exists only in trace amounts and the radioactive element also binds with oxygen and carbon in a fairly stable form that does not interact easily with other chemicals, making the extraction of uranium extremely difficult.
Scientists in China and other countries have come up with various solutions. The most hopeful absorbing material at present being amidoxime, a chemical compound that can capture the floating uranium particles. To improve its efficiency, scientists used amidoxime with other materials, from rare earths to proteins that can strengthen the bond.
The efficiency of uranium absorption materials, for instance, has increased more than 30-fold since the 1960s, according to a recent study by researchers at Tsinghua University.
“Development of seawater uranium extraction technology is expected to become a guarantee of uranium resources for the future development of nuclear energy,” said professor Ye Gang and colleagues at the Institute of Nuclear and New Energy Technology in the study published in the Journal of Tsinghua University in March 2021.
However, the cost to extract 1kg of uranium from the ocean is still high at over US$1,000, or more than 10 times the price to extract it from land, according to one estimate in the Tsinghua paper.
However, a researcher with the Shanghai Institute of Applied Physics, Chinese Academy of Sciences said that besides uranium, the the extraction technology being developed could also be applied to other fields like medicine and defence, and can lead to the development of disruptive technology that goes beyond application in the nuclear sector.