Adsorbents of Radioactive Iodine

Since the nuclear accident happened at the Fukushima Daiichi Nuclear Power Plant (NPP), the NPPs in Japan not only consider prevention countermeasures of nuclear accidents, but also have come to consider safety countermeasures when accidents happen. After the Fukushima accident, it has been confirmed to install a filtered containment venting system (FCVS) as an important countermeasure of preventing radiation exposure. In addition, the countermeasures against organic iodine that could not be done even in Europe are being taken after the Chernobyl accident.
Rasa Industries has been supplying silver zeolite (AgX®) as a radioiodine adsorbent since 1980. After the Fukushima accident, AgX® has been evaluated under severe accident conditions, and its adsorption performance has been further improved. At present, it is being used in FCVS as radioiodine countermeasure. Furthermore, another type of silver zeolite (AgR®) has been also developed for meeting the requirements of NPPs in Europe. It can be used in pressurized water reactor (PWR) containing a high-concentration hydrogen.

■ Main common features of AgX®/AgR®

High adsorption performance under the conditions of high temperature, high pressure and high relative humidity.
High adsorption performance even at low dew point distances (DPDs) (< 5 K).
High adsorption performance even if the condensation of water vapor occurs at the start of venting.
High adsorption performance in the atmosphere containing hydrogen.
Adsorption performance does not degrade even if they are heat treated under the harsh conditions such as 450 °C for 5 days, 145 °C for 100 days and so on.
High adsorption performance will not be lost even if they get wet with water.
Non-inflammability

■ Features of AgX®

High adsorption performance even in low temperature range (evaluated to - 40 °C).
It is possible to replace activated carbon (TEDA·KI).
It is effective to remove the hydrogen in nuclear reactor, nuclear power building and other places.

■ Features of AgR®

Excellent adsorption performance even in high concentration hydrogen-containing gas mixtures in PWR.
High water resistance.
It is possible to improve the safety by using AgR® together with AgX®.

AgX®filter used at Kashiwazaki-Kariwa nuclear power plant, TEPCO.
(It is a public document of TEPCO)

Radioactive noble gas adsorbent

XeA, a new noble gas adsorbent, has been developed for xenon and krypton, the only noble gases that have been considered difficult to adsorb in nuclear power plants.
Under dry conditions, the adsorption performance of XeA is 80 times higher than that of activated carbon for noble gases. XeA is also capable of adsorption even under high humidity, and has been confirmed to be able to adsorb krypton, which is difficult to adsorb.

■ Catalog

高性能放射性物質吸着剤

High-performance radioactive material absorbent

Nuclear emergency shelter
原子力防災シェルタ GX ENERGY プロジェクト

■ Award

Dr. Shinichi Kawamura was awarded for his research on FCVS using silver zeolite adsorption of organic radioiodine under Professor Tadashi Narabayashi at Hokkaido University. This FCVS has been successfully installed in Tokyo Electric Power Company (TEPCO).

RASA INDUSTRIES, LTD.
Akihabara Daibiru Building.,1-18-13, Soto-Kanda, Chiyoda-ku, Tokyo 101-0021, Japan
Phone : +81-3-3258-1842

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