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Seawater Desalination by Using Nuclear Power
A new project to remove the salt from seawater by using nuclear power, which could help solve China's deficiency in water resources, is currently under study, according to the latest issue of Beijing Review.
The project is being jointly undertaken by scientists at the China Society of Nuclear Science and the Beijing Institute of Nuclear Engineer(BINE��.
Research into seawater desalination began as early as the 1960s. To date, 11 seawater desalination plants using nuclear energy are in operation around the world. However, the small scale and high costs of seawater desalination of four to eight yuan per ton is too expensive for China.
The initiator of China's seawater desalination project is Li Zhaoheng, a nuclear expert who majored in nuclear technology during the 1950s at the Moscow Dynamics Institution. He participated in or led reactor projects.
Seawater desalination technology has a long history, Li explains. Currently, the Middle East produces about 60 percent of the world 's desalinated seawater, with distilled petroleum as the heat source. The nuclear reactor is the heat source when nuclear energy is used to desalinate seawater.
The nuclear desalination research team, headed by Li, in light of the natural conditions of China, developed three different models for seawater desalination, 300 million tons, 600 million tons and 1 billion tons respectively. On such a grand scale, nuclear power is the most economical and cleanest source of heat for seawater desalination.
One important index among the many determining the cost of seawater desalination is the proportion of desalination, which refers to the amount of desalinated water obtained when consuming one kg of steam. It represents the energy used during the course of desalinating seawater. To acquire the same amount of desalinated water, the higher the proportion, the less energy is consumed, and the lower the cost.
Two of the latest distillation techniques, which lead the desalination proportion 2.5 times higher than traditional ways, were developed by Chinese scientists and have been adopted for the project.
The most prominent aspect of the project is its scale. Large seawater desalination plants are not needed in some foreign countries where populations are small, but in China, severe water shortages call for desalination of seawater on a large scale. In Li's project, the cost of desalinated seawater will be cut to about 1 yuan per ton because of its large scale.
"Such a large desalination plant needs an investment of several billion yuan, which is reasonable for building infrastructure, " Li notes, "It is also the most economical method among other ones in this regard."
The Project to Divert Water from the South to the North, which is now under debate, requires a 100 billion yuan investment, says Zhang Guoliang, President of the Administration of the Project to Divert Water from the South to the North of the Ministry of Water Resources. Water diverted from the Yangtze River to Beijing will cost 20 yuan per ton when the projects are completed, he adds.
Comparatively, the desalination project costs less. So the government or commercial organizations that engage in the project could profit considerably, Li points out.
"Desalinated seawater is as pure as purified water sold on the market, " Li says. "A small amount of seawater would be added to meet the mineral needs of the human body. After high-temperature treatment, the water is purified, its salt content even lower than that in the piped water we drink now."
Then is the operation safe�� Zhang Jingwu, a senior engineer from BINE, says the project now under discussion will adopt a low-temperature heating reactor, which has a perfectly safe protection system. It is easier to use and much safer, he adds.
In 1993, the International Atomic Energy Agency concluded that using nuclear energy to desalinate seawater could be carried out safely and reliably, without any technical obstacles.
At a public symposium on nuclear energy in Beijing, scientists pointed out that nuclear power is a clean, safe and reliable form of energy.
"Humankind will eventually demand drinking water from the ocean, " said a senior official from the Ministry of Water Resources. Once the seawater desalination project, being explored by Chinese scientists, is adopted by the Government, it will signal China 's success in this new field of peaceful use of nuclear power.
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