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Japan's new N-safety rules mandate stronger countermeasures

Publication Date : 11-04-2013


The Nuclear Regulation Authority approved Wednesday the final draft of new safety standards to be used when judging whether the nation's idled nuclear power plants are ready to resume operations during safety reviews to start from July.

The new standards require utilities to drastically improve countermeasures against serious accidents while setting stricter standards against natural disasters such as establishing secondary emergency control rooms.

The final draft, which limits the operation of nuclear plants to 40 years in principle, is considered to be the summation of a fundamental review of the nation's nuclear regulatory system that was triggered by the crisis at Fukushima No. 1 nuclear power plant of Tokyo Electric Power Co.

Under the new standards, Shikoku Electric Power Co.'s Ikata nuclear power plant in Ehime Prefecture and Kyushu Electric Power Co.'s Sendai plant in Kagoshima Prefecture would be two prime candidates for early restart among the 50 reactors at 17 plants in the nation.

The two nuclear plants have been confirmed as having no active faults in their vicinity, allowing them to focus on measures against tsunami and other disasters such as volcanic eruptions. The other 15 plants have not completed urgent priority tasks necessary before they can be restarted.

The NRA said the screening for the resumption of operations can be carried out simultaneously at up to three nuclear plants. All nuclear power plants have to pass the screening to meet the new standards, which oblige them to prepare not only for natural disasters but also against serious accidents and terrorist attacks.

It has been pointed out that at the time of the outset of the crisis at Fukushima No. 1 nuclear power plant in March 2011, countermeasures against serious accidents had been neglected, because the nuclear regulations came to be regarded as mere recommendations due to the cozy and collusive relationship between the utility and its ostensible governmental watchdog.

For this reason, the NRA was established in autumn last year and has been proceeding with the complete restructuring of the regulatory system, releasing a draft outline of the new standards in February. The new standards will come into effect by July 18, after public opinion has been heard and following official approval.

As regard tsunami, the measures against which were unregulated by any concrete standards, the new standards require each nuclear plant to calculate the largest tsunami that could strike and use the result as a basis for the construction of seawalls.

For earthquakes, the temporal scope of investigations is expanded in the new regulations to 400,000 years. If there is a volcano within a 160-kilometer radius of a nuclear power plant that has been active in the last 10,000 years, detailed research into the possibility of an eruption during the plant's operation period is mandated.

To deal with serious accidents, the plants are instructed to be equipped with a filtered venting system to deal with the possible release of radioactive material from reactors. But five years of grace, within which such venting systems must be installed, is granted to 24 pressurized-water reactors, which are of a different type from the boiling water reactor at the Fukushima No. 1 plant. There are 26 boiling water-type reactors in the nation. The grace period also applies to the establishment of secondary emergency control rooms.


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