A new method to stop highly toxic radioactive strontium in ground water from flowing into the sea using American technology will start in February at the Fukushima Daiichi nuclear power plant.
Among the radioactive materials that were dispersed at the site, the potentially lethal alkaline earth metal poses the biggest immediate concern, because, unlike cesium, it doesn’t get trapped in soil and tends to accumulate in bones of fish and animals if ingested.
The technology to be introduced uses apatite: a mineral that’s similar to bone in its makeup and has the ability to capture and hold certain elements including strontium.
At the Hanford site in southwestern Washington state, where the U.S. government produced more than 20 million pieces of uranium metal fuel for nine nuclear reactors, apatite is used to block strontium from liquid nuclear waste in soil from flowing into the adjacent Columbia river, according to the U.S. government’s website.
“We’ll have to see if the technology works in a salt water environment,” said Tatsuya Shinkawa, director of the Japanese government’s Nuclear Accident Response Office. “It has captured 90% of the strontium in the ground water at the Hanford site. But that site is far from the sea, and this method hasn’t been used in an environment so close to the ocean.”
The government plans to conduct tests from February to May by putting a cylindrical case filled with pebbles covered with apatite into the ground water, and if necessary improve the technology to work with salt water. The case will be about 20 meters long and 1.5 meters in diameter. “If it goes well, we will probably make an apatite wall between the tanks and the sea,” Mr. Shinkawa said.
The use of apatite is one of 780 suggestions from around the world that Japan’s International Research Institute for Nuclear Decommissioning received last year in response to its call for solutions of the contaminated water problem.
Radiation levels in groundwater sampled from several monitoring wells have been very slowly rising since last summer and radioactive strontium has been detected since October, according to data from Tokyo Electric Power Co., which operates the Fukushima Daiichi plant. Leaks started in early 2013, and Tepco considers the time gap came because radioactive materials tend to move slowly in underground.