Tuesday, December 11, 2012

Trouble on the Nuclear Ginza

The only nuclear plants to reopen in Japan since the March 11, 2011 disasters are Kansai Electric's Oi #3 and #4 plants in Fukui Prefecture, two of the more modern, larger plants in Japan.

Various other plants are now under inspection as one step to reopening.  One of the next in line is the Tsuruga #2 plant, only a short distance to the east in Fukui Prefecture from Oi, on a peninsula along the Japan Sea Coast.  The Tsuruga #1 and #2 plants are located near the older and smaller, somewhat accident prone, Mihama plants, which I suspect will never reopen.  The Tsuruga operator, Japan Atomic Energy, had planned to build Tsuruga #3 and #4 reactors as well over the next 5-7 years.  This area also hosts the accident-prone Monju experimental fast breeder reactor, and is known in Japan as the "nuclear Ginza", because of the crowded real estate and the massive subsidies that Fukui Prefecture has gotten over the years.
Sunset over the Tsuruga Peninsula.  The nuclear facilities are on the far side, out of sight.
The new regulatory agency in charge of nuclear safety, the Nuclear Regulation Authority ("NRA") has been examining claims from some seismologists that a "crush zone" of rock under the Tsuruga #2 Plant (the "D-1 Fault" which is said to branch off of the nearby, active "Urasoko Fault") is an active earthquake fault.  Under pre-existing Japanese rules, "active" means something like "has moved in the past 120,000-130,000 years".  (It would not be surprising to me if any place in Japan is not considered on or near an "active" fault, under that definition, which really gets to the heart of the unique problems with siting reactors in this country).  Based on inspections to date, it seems all members of the relevant commission believe the D-1 Fault is likely an "active" fault, and the commission is considering next steps.  Most likely, they will conclude that the plant should never have been sited at its location ... and will not be permitted to reopen.  This is the lead story in the Japanese press today, and English reports can be found on AP and NHK websites.

Tsuruga Plant #1 was completed in 1970, shut down in March 2011, and was never a likely prospect to reopen, being over 40 years old and relatively small.  Tsuruga Plant #2, however, was completed in 1987 and, when operating, provides baseload power of over 1100MW to the Kansai area.

There is also a pending investigation of "crush zones" beneath the Oi #3 and #4 reactors, and a divided opinion over whether or not they represent an "active" fault.

UPDATE May 2013:  The NRA has completed its process and formally concluded that the "cursh zone" under the Tsuruga #2 reactor is an active fault ... making it virtually impossible that this reactor will reopen.

Meanwhile, efforts to restart the experimental Monju fast breeder reactor (nearby Tsuruga) have been dealt a severe blow, as the operator has been found to have failed to conduct regular equipment inspections over the lengthy period it has been inoperable.

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