Wastewater Treatment at Fukushima Daiichi Nuclear Plant

Kurion delivered the first-ever external cooling system for a nuclear reactor, which was responsible for 70% of the radioactivity removed from the water in the first nine months of operation

Fukushima, Japan

Situation Overview
Following the March 2011 earthquake and tsunami that devastated Japan, Tokyo Electric Power Company (TEPCO) resorted to using seawater to cool the reactors at the Fukushima Daiichi Nuclear Power Plant. Without a functioning cooling system, TEPCO needed to add millions of gallons to cool the reactors. TEPCO was in a race against time – by the middle of April, the plant’s basements and buildings were filling with contaminated water and the rainy season was weeks away, threatening to flood the plant and spread radiation. The company needed a solution to cool the reactors and clean the contaminated water.

Kurion was tasked with building the first-ever external water-cooling system for a nuclear reactor before the plant flooded and heightened the catastrophe. During the crisis situation, specifications were changed daily as new information emerged from the site.

 

Regulatory Process


Due to the nature of the crisis, Kurion’s technology was evaluated simultaneously by TEPCO and Japan’s national laboratories and other nuclear companies. The evaluation team was reassured by the fact that the ISM technology dates back to the cleanup of Three Mile Island and was shown to be effective and vitrifiable.

Remediation Approach
The primary objective was to remove cesium from the millions of gallons of wastewater, as cesium was the principal source of radioactivity at the site and the greatest safety risk to the site and environment from a dose standpoint. Cesium was in high abundance due to the failed fuel. Furthermore, it is a strong gamma emitter and the sole ionizing radiation found in nuclear waste that can penetrate piping.

ISM is an inorganic media that uses ion exchange to surgically isolate specific isotopes, in this case, cesium. Additionally, ISM works as a molecular sieve and adsorbent, which preserves its performance as an isotope sorbent in aqueous solutions with salt water and other common interferents present.

Kurion was in a unique position to help – unlike conventional media, Kurion’s ISM has low sensitivity to pH, salt water, and the presence of surfactants (e.g., soap) in wash waters. The inorganic ISM is also resistant to radiation, mitigating the stability concerns associated with organic ion exchange resin under high radiation applications. Finally, it can be produced in large quantities and could meet TEPCO’s significant need.

In addition to providing its ISM, Kurion designed and constructed the entire cesium-removal portion of the overall process system. This processing system has several stages, including debris and oil removal, radioactivity removal (Kurion’s role), and desalinization. The goal was to process radioactive contaminated water that was presently in the turbine buildings, along with new cooling water added daily, and return the purified water to the plant to recycle as reactor cooling water.

Results
Kurion delivered the first-ever external cooling system for a nuclear reactor in five weeks:

  • On-time delivery in a five-week design/fabricate/delivery cycle with frequent and significant specification changes right up to shipment
  • The system was assembled at Fukushima in nine days followed by only one day of cold commissioning and three days of warm commissioning before hot startup with actual wastewater
  • In its first three months, the cesium-removal system achieved its cesium removal goal of 99.9%
  • In its first year of operation, Kurion’s cesium removal system was responsible for 70% of the radioactivity removed from the wastewater
  • Effectiveness of system helped TEPCO achieve its goal to declare the end of Phase I of its “Roadmap towards Restoration from the Accident” when the plant reached Cold Shutdown status on December 16, 2011
  • One year after the tsunami, the water cooling system had processed more than 258,780 MT (68 million gallons), reduced salinity by almost 90% and was estimated to have removed about 12 million curies (4.4 x 1017 Becquerel) of the estimated original 13.6 million cesium curie inventory (5 x 1017 Becquerel)”
  • Click here to see Kurion CEO John Raymont share the company's experience at Fukushima at the March 8, 2012, Keizai Society event to mark the anniversary of the earthquake and tsunami