Utilities Unbundled issue 13

TEPCO’s roadmap to recovery

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More than a year and a half after the Fukushima Daiichi nuclear accident, we look at progress decommissioning the stricken plant.

The operator of the Fukushima Daiichi nuclear power station is now addressing both the short-term and long-term effects of the accident.

The events of March 2011, when a tsunami caused catastrophic damage to Japan’s Fukushima Daiichi nuclear power station, are well known. Operator TEPCO is now addressing both the short-term and long-term effects of the accident.

First priority was to stabilize

In December 2011, TEPCO and the Japanese Government – which took control of the utility in July 2012 as part of a ¥1 trillion (US$12.5b) bailout – released a jointly constructed three-phase roadmap (see Figure 1) detailing plans to ensure its long-term safety.

TEPCO’s Executive Vice-President and Chief Nuclear Officer, Zengo Aizawa, comments, “Understandably, the roadmap’s most pressing aim was to bring the situation under control as quickly as possible.”

Once initial objectives to bring radiation under control were met and the plant was stabilized, efforts turned to ensuring the long-term safety of the plant.

As part of this process, TEPCO is taking steps to:

  • Remove nuclear fuel stored in the plant’s spent fuel pools
  • Remove fuel debris from the reactor pressure vessels (RPVs) and the primary containment vessels (PCVs)

Lessons from Three Mile Island

Aizawa, who is leading the roadmap process, says fuel debris removal will be complex, challenging and drawn out. Major R&D efforts will be required to support the process and restore the PCVs. Works are expected to be completed in 2021.

“The critical judgment point for removal of fuel debris will be stopping interbuilding water leakage from the reactor turbine building and repairing the lower part of the PCVs.”

He explains that TEPCO may apply a technique based on one used after the 1979 Three Mile Island disaster in New York. “We believe that removing under water, where radiation is shielded effectively, may be the most reliable solution at the present moment.”

Working with government and industry

Aizawa says that while TEPCO is leading the decommissioning process, it is collaborating with other government bodies, including the Agency of Natural Resources and Energy and the Nuclear Regulatory Agency, as well as technical experts.

Together with the Japanese Government, TEPCO has established a research institute. The Research and Development Headquarters will contribute to the roadmap’s R&D activities. Institute members include Japan Atomic Energy Agency, Hitachi, Ltd./Hitachi-GE Nuclear Energy, Ltd. and Toshiba.

Robotics and remote technology

TEPCO is drawing on the most advanced applicable technologies from around the world to deal with some of the more challenging aspects of the removal process, including the high x-ray emission and extremely limited space inside Fukushima Daiichi’s units.

“We plan to adopt robotics and remote technology for decontamination work, investigation of leaking parts and fuel debris inside reactor turbine buildings, PCVs, RPVs, repair of leakage parts and the fuel debris removal processes.”

Whatever the future holds for the Japanese nuclear sector, TEPCO is confident that the lessons learned from Fukushima Daiichi mean it is ready to play its part.

For more information, contact Ryuzo Shiraha.

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