Jeremy L. Dillon
RW Monitor
2/20/2015
While Japan and the Tokyo Electric Power Company have made “significant progress” in cleanup of the Fukushima-Daiichi Power Station, a preliminary report this week on the cleanup by the International Atomic Energy Agency warns that the most intensive work still remains ahead. Since the last IAEA review of the cleanup in 2013, TEPCO has made significant strides in expanding efforts to curtail groundwater contamination while also removing all fuel from Reactor Four. The IAEA also praised the company for establishing a new decommissioning entity, the Fukushima Daiichi D&D Engineering Company (FDEC), as a way of giving clear responsibilities for cleanup in the organization.
While progress has been made, the most difficult parts of the cleanup— removing damaged fuel and radioactive waste management—still need solutions, IAEA said. “Japan has made significant progress since our previous missions. The situation on the site has improved – progressive clean-up has led to reduced radiation dose levels in many parts of the site,” IAEA Director of Nuclear Fuel Cycle and Waste Technology Juan Carlos Lentijo said in a statement. “The situation, however, remains very complex, with the increasing amount of contaminated water posing a short-term challenge that must be resolved in a sustainable manner. The need to remove highly radioactive spent fuel, including damaged fuel and fuel debris, from the reactors that suffered meltdowns poses a huge long-term challenge.”
Groundwater Contamination Shrinking, But More Work Needed
The IAEA’s preliminary report recommended that TEPCO find ways to increase the performance and capacity efficiency of the existing water treatment technologies to better address the problem. “While recognizing the usefulness of the large number of water treatment systems deployed by TEPCO for decontaminating and thereby ensuring highly radioactive water accumulated at the site is not inappropriately released to the environment including the adjacent Pacific Ocean, the IAEA team also notes that currently not all of these systems are operating to their full design capacity and performance,” the report said. “The IAEA team encourages TEPCO to continue on-going efforts to improve the utilization of these treatment systems. In their planning of water treatment schedules, TEPCO is advised to take into consideration that testing and optimizing the operating conditions of complex multi-stage water treatment systems can take time, particularly for those technologies that are new and being deployed under field conditions for the first time.” The cleanup added a new high-powered ALPS system last fall while also constructing a sub-drain system that will capture underground water and pump the water for treatment.
TEPCO has also been working on contamination prevention for the groundwater. Early 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. Each system is part of TEPCO’s three large water management strategies: Contaminant removal, contaminant isolation, and leakage prevention.
Long-Term Waste Plan Needed, Report Says
The IAEA also recommended that TEPCO establish a firmer long-term strategy for the management of radioactive waste at the site. Currently, the plan is to build interim storage to hold the site’s waste, but a long-term strategy has not been established yet. IAEA did credit TEPCO and Japan for establishing an organizational structure to look into the matter, but plans should develop sooner rather than later, the report said. “The IAEA team is of the opinion that the FDEC could better employ long-term radioactive waste management principles (beyond the segregation, relocation and dose reduction/shielding currently performed) such as more complete waste characterization, conditioning, and packaging,” the report said. “While the IAEA team holds that the FDEC could deploy such principles in its present efforts, it appreciates that waste management strategy, direction and criteria are forthcoming from the [Nuclear Damage Compensation and Decommissioning Facilitation Corporation].”
