A little more than a month after the March 11, 2011 Great East Japanese Earthquake and Tsunami damaged the Fukushima Daiichi Nuclear Plant, the Tokyo Electric Power Company (TEPCO) announced the selection of Toshiba (oil/grease separation), Kurion (cesium removal), AREVA (cesium removal), and Hitachi (desalination) to provide an unprecedented external reactor water cooling system rated at 1200 MT/day (317,000 gallons/day -- about 15 backyard swimming pools/day). The mission of these first responders was to quickly reduce the safety and environmental risks presented by the increasing and very large quantity of highly radioactively contaminated, oily and saline water that was creating a high dose concern on site and restricting entry into the reactor and turbine buildings. The system started operation June 17, less than 100 days following the tsunami (compares with about 18-months for startup of the cesium removal system at Three Mile Island used to process 790,000 gallons (2650 MT) of high activity water, or 2.5 days of processing for the TEPCO system).
"One year after the tsunami, the water cooling system has now processed more than 258,780 MT (68 million gallons), reduced salinity by almost 90 percent and estimated to have removed about 12 million curies (4.4 x 10^17 Becquerel) of the estimated original 13.6 million cesium curie inventory (5 x 10^17 Becquerel)" (refer to graphic). "These are astounding figures," Raymont said, adding that "the initial inventory is approximately 27 times the annual disposal of all curies of activity for the US fleet of 104 reactors in the US, some 507,000 curies (1.9 x 10^16 Becquerel)" (see above).
"TEPCO wisely decided on a defense-in-depth strategy of developing redundant cesium removal systems. This was driven by cesium being far and away the safety risk to the site and environment from a dose standpoint, given its high abundance due to the failed fuel and it being a strong gamma emitter, the sole ionizing radiation found in nuclear waste that can penetrate piping," said Dr. Mark Denton, Kurion's Chief Technology Officer. "Of the cesium removal systems the Kurion system is the sole system to see the high-activity high-salinity water found at initial cooling system startup in June." This is because the AREVA system operated "behind" the Kurion system as a "polisher" by taking its effluent water and removing the last tenths of a percent of activity. By starting up more than two months later and initially located behind the Kurion system as per the AREVA system, the SARRY system simply missed out on the higher activity water and salinity; never seeing more than 60 percent of the level of the cesium concentration or 50 percent of the salinity present in June. As a result, the Kurion system has processed about 53 percent of all the waste water processed to date but is responsible for about 70 percent of the cesium activity removed.
If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks