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Nuclear watchdog gives nod on safety to two aging reactors for first time


The No. 1 reactor, in the background on the right, and the No. 2 reactor beside it are seen at Takahama nuclear power plant in the town of Takahama, Fukui Prefecture. The No. 3 reactor, in the foreground on the right, restarted its operation in January this year while the No. 4 reactor next to it is expected to restart its operation Feb. 26 at the earliest.

For the first time, Japan’s nuclear watchdog has disclosed that two aging nuclear reactors in operation for more than their basic lifespan of 40 years have passed the new safety standards set after the 2011 Fukushima disaster.
The No. 1 and No. 2 reactors of the Takahama nuclear power plant in Fukui Prefecture could now have their operations extended for a further 20 years as the Nuclear Regulation Authority made the announcement on Feb. 24.
To extend the operational lives of the two reactors, operator Kansai Electric Power Co. must receive NRA approval by July on three outstanding items–safety measures, detailed designs and extension of operations.
This is the fourth time the NRA has acknowledged that nuclear reactors are meeting the new safety standards, but the first time for those that are at least 40 years old.
The other three cases were the No. 1 and the No. 2 reactors at the Sendai nuclear power plant in Kagoshima Prefecture, operated by Kyushu Electric Power Co.; the No. 3 and the No. 4 reactors at the Takahama plant; and the No. 3 rector at Ikata nuclear power plant in Ehime Prefecture, operated by Shikoku Electric Power Co.
After the triple meltdown at the Fukushima No. 1 nuclear power plant in March 2011, laws on nuclear safety were revised. As a result, it was stipulated that the operation period of nuclear reactors is a basic 40 years but that can be extended by up to 20 years–but just one time–with NRA approval.
Although the No. 1 and the No. 2 reactors at the Takahama plant have been operating for more than 40 years, it is a transitional measure until July as Kansai Electric Power has yet to obtain NRA approval for a 20-year extension.
In March 2015, the utility asked to be screened by the NRA to ensure it was meeting the new safety standards. In April 2015, it applied for an additional 20 years for each reactor.
The NRA has been conducting intensive screenings on the reactors because if Kansai Electric Power cannot obtain approval on safety measures, detailed designs and extension of operations by the July deadline, it will have to decommission the two reactors.
In the safety screenings, the main focus was on fire-prevention measures with regard to electric cables. The No. 1 and No. 2 reactors were using cables totaling 1,300 kilometers in length, but they were not fire-retardant.
The utility responded by replacing 60 percent of them with fire-retardant cables, and wrapping the remaining 40 percent with fire-retardant sheets. This met with NRA approval.
With regard to earthquake and tsunami resistance, the utility used the same levels as those for the No. 3 and the No. 4 reactors at Takahama plant, both of which had already been approved by the NRA as meeting the new safety standards.
The NRA devoted 389 pages of the screening paper to its opinion that the No. 1 and the No. 2 reactors at Takahama are meeting the new safety standards. The NRA will collect opinions from the public about its conclusions for 30 days from Feb. 25 and then formally decide whether the two reactors are meeting the new standards on safety measures.
At the same time, it will go ahead with screenings on the remaining two items–detailed designs and the extension of operations. The screening on the detailed designs will focus on quake-resistant capabilities of important facilities. The screening on the extension of operation will check on the deterioration of facilities.
Even if Kansai Electric Power obtains approval on all of the three items, it will take about three years for the utility to finish work on safety measures. Because of that, the operations of Takahama’s No. 1 and No. 2 reactors are not expected to be restarted before autumn 2019.

February 24, 2016 - Posted by | Japan |

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