For Nuclear Power Plant Site Restoration Technology
Hyundai E&C has recently obtained Green Certification from the Ministry of Environment for its technology to restore decommissioned nuclear power plant sites.
Green Certification is a national certification system certifying a green technology or a promising green project to support green investment as part of the government´s "Low Carbon Green Growth" policy.
Hyundai E&C’s certified technology reduces radioactive cesium-contaminated soil waste using particle size classification and a cation exchange washing process. This technology removes cesium attached to soil by classifying soil contaminated with radioactive materials by particle size and then washing it with a potassium chloride (KCl) solution.
Most radioactive materials have a small particle size and adsorb to fine soil with a large surface area. Therefore, it is key to precisely select and wash soil particles to effectively remove adsorbed pollutants. It is very important to reduce the amount of radioactive waste generated in the process of dismantling nuclear power plants because the disposal cost is high as well as greenhouse gas emissions from the construction of the disposal facility.
In particular, Hyundai E&C used potassium chloride as washing process water to remove cesium, a radionuclide highly likely to be present at a decommissioning site of a nuclear power plant. Using ion exchange reactions between potassium and cesium, can make cesium fall off from clay soil. Then the process of selectively adsorbing and removing cesium in washing process water is carried out. The washing water from which the cesium has been removed is 100 percent reusable and produces no secondary waste.
To assess the performances of the technology, Hyundai E&C ran a pilot test using a demonstration facility with Korea Hydro & Nuclear Power (KHNP) which is in charge of nuclear power plant dismantling projects. Verification items were particle size separation accuracy, soil cesium and heavy metal removal rates, adsorbents’ adsorption performance, a process water cesium removal rate. The technology succeeded in removing 90 percent of the cesium from radioactively contaminated soil of 900 kg or more per hour, proving itself as a viable commercial technology for the decommissioning of nuclear power plants.