Jeremy L. Dillon
RW Monitor
3/13/2015
As this week marked four years after the disaster at the Fukushima-Daiichi nuclear site, the Tokyo Electric Power Company (TEPCO) reported this week that 750 tons of rainwater containing Strontium-90 may have seeped into the ground at the cleanup site. Following heavy rains at the site, water accumulated in the outer dyke of the H4 tank area, which has had problems with leaking tanks in the past. TEPCO, though, made assurances that the contaminated water would not reach the ocean. “It has been confirmed that there is no inflow into the closest drainage channel located to the sea side of ‘H4’ area, nor any significant change in the monitored radioactivity level in the drainage,” TEPCO said in a release. “After taking initial measures such as pumping out rainwater from the outer dyke, the company said it will continue to take steps to contain rainwater such as further waterproofing the outer dyke.” TEPCO said it is investigating the cause of the rainwater contamination and will report its findings as soon as possible.
Four Years Later, TEPCO Making Progress
This week marked four years since the earthquake and tsunami caused the disaster at the Fukushima plant. While there have been some problems along the way, TEPCO has made strides in getting the site contamination issues under control. Groundwater contamination prevention as well as decontamination efforts have been the major immediate cleanup goals at the site. TEPCO has instituted a wide reaching water management strategy that includes prevention and treatment of contaminated water contamination. “Four years after the accident, the progress at the site is remarkable,” Former Nuclear Regulatory Commission Chair and current Nuclear Reform Monitoring Committee Chair Dale Klein said in a statement. “At the same time, it is clear that much more needs to be done, and I applaud President Hirose for his emphasis on safety over scheduling, and his expression of concern for the people of Fukushima.”
The installation of a new high-powered ALPS system last year, along with other water management activities, has TEPCO making strides against water contamination. Last year, the company announced the launch of its by-pass system that diverts groundwater from the site. The bypass system is an attempt to reduce the accumulation of contaminated water by intercepting the clean groundwater before it reaches the plant by rerouting it around the plant into the sea. TEPCO also began construction of an ‘ice wall,” which freezes the surrounding soil in an effort to block the flow of groundwater. The strategy also includes the construction of a seaside wall aiming to prevent groundwater from flowing into the sea by constructing a steel pipe sheet pile wall on the east side of the site and construction of a subdrain system that will capture underground water and pump the water for treatment. All four systems are part of TEPCO’s three large water management strategies: Contaminant removal, contaminant isolation, and leakage prevention.
Challenges Still Remain
While progress has been made, the most difficult parts of the cleanup— removing damaged fuel and radioactive waste management—still need solutions. The fuel rods at Units 1-3 all suffered heavy damage, resulting in fuel debris, and are not so easily transferred. “Since the fuel melted into a state called debris, it became difficult to apply conventional measures to remove it,” TEPCO said. “To deal with this situation, we are planning to conduct the task in parallel with the development of tools and devices for removal, etc. during the decommissioning process, over the next 30 to 40 years.” TEPCO, along with the Japanese government, have launched major research and development initiatives to better develop technology to aid in the cleanup of the damaged fuel.
