Fukushima Daiichi NPS Prompt Report 2015

IRID and TEPCO announce new schedule to insert robot while finding a solution to clear obstacles in its path

Fukushima, August 7 - The international Research Institute for Nuclear Decommissioning (IRID) and TEPCO are continuing with preparations for the insertion of the latest robot into the Unit 2 reactor at Fukushima Daiichi, while IRID and TEPCO have announced a new schedule for the insertion.

The robot, developed by IRID and Toshiba, is designed to investigate conditions inside the reactor's Primary Containment Vessel (PCV). Sending the robot into the PCV is expected to provide valuable insight into the appropriate procedures and methodologies required for fuel debris removal.

Before the robot actually enters the PCV, a telescope is used to investigate whether its path is clear. The telescope is equipped with a camera to visualize the path, a dosimeter to measure the radiation level and a mechanism to remove small rubble along the path.

Upon initial inspection of the Unit, however, rows of concrete blocks for shielding high radiation were found in front of the x-6 penetration pipe. The x-6 penetration pipe is one of the penetration pipes that connect the inside and outside of the PCV and it will be used as a path for the telescope and the robot to reach the PCV. The solution for this has been to remove the concrete blocks using a remote-controlled device.

Currently, 128 of the 135 concrete blocks have been removed. The most difficult maneuver in the process remains, however: removal of the final row of blocks, which are stuck together adhered due to rust and embedded in the concrete floor, presenting a unique challenge. There have been several attempts to safely remove the final row and IRID and TEPCO continues to refine its equipment, technology and strategy to remove them safely. The goal is now to completely remove the concrete blocks by the end of November.

The new schedule is in keeping with the "safety culture" policy - to move forward with urgency but always to place safety considerations above arbitrary timetables.

In the interim, attempt to understand the conditions inside the reactor, particularly the condition of the formerly molten nuclear fuel, will continue by obtaining information using the muon technology.

[About TEPCO] Tokyo Electric Power Company, Inc. (TEPCO) is Japan's largest power company, supplying energy to the greater Kanto area, including Japan's two most populous cities, Tokyo and Yokohama. Its 34,000 employees are committed to providing safe, reliable power to its 29.0 million customers, diversifying energy resources to ensure sustainability, and contributing to economic growth while fully meeting its responsibilities after the Fukushima Daiichi accident.
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