Report on implementation of Nuclear Safety Reform Plan also describes continuing improvements at Kashiwazaki-Kariwa
TOKYO, August 2—Progress in freezing the soil around Units 1 through 4 to form “ice wall” and advances in understanding the location and condition of the fuel debris in Unit 2 at Fukushima Daiichi Nuclear Power Station highlight the latest quarterly progress report on TEPCO Holdings’ implementation of its Nuclear Safety Reform Plan.
The Plan, adopted in April 2013, calls for a variety of specific improvements at the company’s three nuclear facilities as well as overall management and procedural improvements. Progress reports are produced quarterly, and this report covers the first quarter of the company’s fiscal year 2016, which began April 1.
Progress at Fukushima Daiichi
The report describes the progress made in freezing the soil to provide a water-tight perimeter around Units 1 through 4 at Fukushima Daiichi Nuclear Power Station. The perimeter is intended to keep groundwater from entering the reactor or turbine buildings and becoming contaminated. The “ice wall” uses technology similar to that of a skating rink to freeze the floor, but areas where groundwater flows fast have proved somewhat more difficult to freeze, so additional steps are being taken to assist freezing. (These developments were independently reported previously and are summarized in the quarterly report. For the initial report, and more details, go to https://www4.tepco.co.jp/en/nu/fukushima-np/handouts/2016/images/handouts_160728_02-e.pdf#page=20)
Also at Fukushima Daiichi, progress was made in the challenge to precisely locate and analyze the fuel in Unit 2 that had melted in the reactor core and then resolidified after the March 11 accident. This is a necessary step in devising a plan to safely extract it, a key goal in the long-term decontamination process. Radiation levels inside the Unit 2 reactor building remains high, so this examination is being conducted using muon cosmic rays and later with remotely-controlled robots. The quarterly report includes preliminary findings of the muon measurement, some shadows indicating the main structures of the containment vessel. (More recently, the muon findings were analyzed. For the latest information, go to https://www4.tepco.co.jp/en/nu/fukushima-np/handouts/2016/images/handouts_160728_01-e.pdf)
A broad range of safety measures being implemented at Kashiwazaki-Kariwa Nuclear Power Station were recounted in the report. With extensively strengthening of the plant’s countermeasures, Units 6 and 7 are being reviewed by the Nuclear Regulatory Authority to confirm their compliance to the New Regulatory Requirements. A highlight of the report is the installation of a Corium shield to protect the containment vessel from molten fuel in the event of a serious accident and the replacement of light oil storage tanks with ones using thicker steel plates to prevent them from being hit by flying objects that could be caused by tornadoes.
The report also notes the findings of the third-party verification committee concerning the belated acknowledgment that a “meltdown” had occurred during the March 11 accident, and the things the company will do to ensure that future communications are thorough and timely. (This also has been previously reported – see https://www7.tepco.co.jp/newsroom/press/archives/2016/1300509_7763.html for more detail.)
As has become customary in the quarterly reports, key performance indicators are used to measure implementation of a wide variety of management and procedural enhancements called for by the Plan. They evaluate various categories relating to senior leadership, safety awareness throughout the organization, emergency preparedness, and more. Among the management enhancements discussed in depth are improvements in the ability to propose “defense in depth,” risk communication activities, and training for emergency response.
A summary of the progress report can be seen at https://www4.tepco.co.jp/en/press/corp-com/release/betu16_e/images/160802e0101.pdf.
The full report is available at https://www4.tepco.co.jp/en/press/corp-com/release/betu16_e/images/160802e0102.pdf
About TEPCO Holdings Group
Tokyo Electric Power Company Holdings, Inc. (TEPCO Holdings) is Japan's largest power company group, holding three independent business entities: TEPCO Fuel & Power, Inc., TEPCO Power Grid, Inc., and TEPCO Energy Partner, Inc. As a group, it generates, distributes, and sells electricity and other types of energy principally to the Kanto metropolitan area, which includes Japan's two most populous cities, Tokyo and Yokohama. Its 33,000 employees are committed to providing safe, reliable power to its 29 million customers as well as fulfilling its responsibilities to the communities of Fukushima. (As of April 1, 2016)
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