30 Novembre 2015
November 30, 2015
A nuclear reactor believed to sit above an active fault should never be restarted.
A Nuclear Regulation Authority expert panel report that will likely be finalized says there is an undeniable possibility that an active geological fault line runs directly beneath the Shika nuclear power plant’s No. 1 reactor building in Ishikawa Prefecture.
The nuclear watchdog’s regulation standards do not allow key equipment, such as a nuclear reactor, to be built on an active fault.
The basic principle should be: “When in doubt, leave it out.”
Hokuriku Electric Power Co., operator of the Shika nuclear plant, should take bold steps to decommission the No. 1 reactor.
However, the company, which says its own studies show the fault is not active, has angrily retorted that the NRA panel’s decision cannot be called rational.
The regional utility has already filed an application with the NRA to restart the nearby No. 2 reactor, and is set to maintain its counterarguments during screenings of that application.
Even experts find it difficult to decide if a given underground fault has the potential to move.
The suspicion that the fault is active arose from geological sketches made before the Shika nuclear plant was built. But newer strata layers that could have helped provide a more accurate assessment were scraped away during construction work at the site.
In addition to twice conducting on-site investigations, the expert panel has comprehensively examined the terrain, bedrock and other features in surrounding areas. The panel had its findings verified by third-party experts before deciding to reject Hokuriku Electric’s arguments.
The panel’s decision should not be taken lightly.
Continuing to argue against the NRA would require additional survey expenses. Hokuriku Electric’s work to ensure the No. 2 reactor will comply with the regulation standards is already expected to set the utility back between 150 billion yen ($1.22 billion) and 200 billion yen.
The No. 1 reactor has proved extremely difficult to bring back online, and continuing to spend money on such efforts could hardly win the understanding of users.
The No. 1 and No. 2 reactors of the Shika nuclear plant have remained offline since they were halted immediately before the Fukushima No. 1 nuclear plant disaster. But the halt of their operations has never caused a major problem with supply and demand of electricity. Hokuriku Electric has mostly remained in the black even after the 2011 disaster, and its power rate levels are the lowest in Japan.
Hydropower accounts for one-quarter of the power generated by Hokuriku Electric, which serves an area with abundant water resources from the Northern Japan Alps. That gives the company the option of making the most of its geographical advantage and being reborn as a utility without a nuclear plant.
The shortest way to prevent a repeat of a Fukushima-like disaster is to close down nuclear reactors based on their risk levels. We do hope Hokuriku Electric will set a pioneering example.
The Shika No. 1 reactor, in service only since 1993, is a relatively young one in Japan. Decommissioning it would be a tough decision for management.
The government, however, altered accounting rules in spring this year to help facilitate decommissioning procedures. For example, electric power companies are now allowed to write off decommissioning-related losses in 10-year installments to reduce the potential burden from such procedures.
Total liberalization of the power retail market is expected next spring, spelling the end of the regional monopolies of electric utilities, whose management prowess will come under more serious scrutiny.
We hope Hokuriku Electric will make a decision with an eye toward that future.
--The Asahi Shimbun, Nov. 29