news digest
Fukushima: SARRY seems to be the cleanest word
In March, one year following the worst nuclear plant disaster since Chernobyl, the various long stages of cleanup were under way. EnergySolutions, a company based in Salt Lake City, Utah, was selected by Toshiba in Japan to begin the vast clean-up of the large volume of radioactively contaminated water at the damaged plant. Toshiba was previously selected in a bid for the work put out by the plant’s owners, Tokyo Electric Power Company (TEPCO). EnergySolutions will support Toshiba in designing and installing the system to decontaminate the water to levels satisfying the strict safety limits announced by the Japanese Government. The regional government in Fukushima City has set a clean-up target of one millisievert of radiation exposure per year, the low end of the international set range. The water to be treated has been utilised
following efforts by TEPCO to stabilise the plant and treat the cooling water with
International safety experts view the damage of Unit 3 of the Fukushima Daiichi Nuclear Power Plant. This picture has come to represent the concerted global concern and ensuing efforts to mitigate the consequences of the accident, leading to a number of initiatives to further enhance the global nuclear safety regime.
sufficient decontamination to allow its continued use as a coolant for the reactors. Since October 2011, the reactors have been in cold shutdown mode, to stabilise the temperature of the cores to below 100° Celsius. TEPCO and Toshiba have been using the Simplified Active Water Retrieve and Recovery System (SARRY) to remove some of the cesium and other contaminants from 125,000 cubic meters of water, mostly sea water used to cool the six reactors during the emergency following the accident in which three of them suffered meltdown. The water must be reused as badly needed coolant. But it still contained 300-1,000 Becquerel cesium/l when EnergySolutions took over the decon operation. EnergySolutions will utilise its
IAEA sea sampling map showing inshore sea contamination that hugged the coast down to Tokyo in April 2011.
Advanced Liquid Processing System (ALPS) to remove the 60 radionuclides present in the water, as well as the cesium already removed so far. Strontium-90 is one of them – a reminder of the contamination of milk which followed the Windscale fire in the UK in 1957. The company’s decon team will also have to treat and package in high-intensity containers (HICs) the secondary wastes which are left over after
decontaminating the water. SARRY uses two ion exchange processes
to remove cesium-134, cesium-137 and strontium-90 from the seawater. The first is a bulk-removal, ion-exchange process which exchanges sodium for cesium or strontium within an inorganic, crystalline structure. The second utilises, also through an ion exchange process, a highly selective media to capture more radioactive elements in the presence of ions other than sodium – including potassium, magnesium, and calcium. Also involved, with several other
companies, is US company Kurion, which has already processed 36 million gallons of contaminated waste water and removed 9.4 million curies of cesium. Kurion’s ion specific media system soaks up nuclear particles and reduces them down for vitrification – a tried and tested process in the industry for encapsulating nuclear waste. The Kurion process is modular, thereby allowing materials to be removed for storage. Forests will be the most challenging
areas for removing radioactive topsoil as 70% of the contaminated land is forested and mountainous.
EQUIPMENT WIPES FOR THE US ARMY
First Line Technology is making Joint Sensitive Equipment Wipes (JSEWs) for the US Army’s Aberdeen Proving Ground for the Decontamination Family of Systems (DFoS) Program. The JSEWs contain FiberTect, an activated carbon wipe for dry decontamination. According to Army Contracting Command, the aim is to field a JSEW that
provides immediate operational decontamination capabilities for sensitive equipment without adversely impacting the operational life or performance of the target assets. Sensitive equipment includes weapons system optics and electronic equipment; non-sensitive equipment includes vehicles, hard shelters and material
10 | CHEMICAL AND BIOLOGICAL WARFARE | 2012/01
handling equipment. Each JSEW contains FiberTect wipes and is to be tested by the Department of the Army. FiberTect is a three layer, flexible, drapable, non- woven composite substrate for absorbing and adsorbing CWAs, TICs, and small particulates such as radiological and biological particles. It is self-contained and packaged for easy storage.
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