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Japan’s nuclear safety chief raps Tepco’s attitude on Fukushima No. 1 crisis, restarting other reactors

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The head of the Nuclear Regulation Authority told Tepco’s top management he questions their attitude toward decommissioning the Fukushima No. 1 nuclear power plant and the company’s ability to resume operating its other reactors.

I feel a sense of danger,” NRA Chairman Shunichi Tanaka said during a special meeting Monday with the top management of Tokyo Electric Power Company Holdings Inc.

Tanaka also said Tepco does “not seem to have the will to take the initiative” toward decommissioning the crippled nuclear power station that suffered three reactor meltdowns in March 2011.

Tepco Chairman Takashi Kawamura and President Tomoaki Kobayakawa attended the meeting. The authority felt it is necessary to hear from the top executives before it could make a decision on whether to approve Tepco’s plan to resume operation of reactors 6 and 7 at its massive Kashiwazaki-Kariwa plant in Niigata Prefecture.

Tepco filed for a safety assessment of the two reactors in September 2013 to reactivate them, hoping to restore its financial condition as it needed massive funds to pay compensation related to the Fukushima disaster and to scrap the plant.

The NRA’s safety screening found that Tepco failed to report insufficient earthquake resistance for an emergency response center at the Niigata complex even though it knew about the insufficiency for three years.

In June, Tepco submitted to the watchdog its revised safety measures for the Kashiwazaki-Kariwa complex.

An operator lacking the will to take the initiative does not have the right to resume operation of nuclear reactors,” Tanaka said.

Tepco’s chairman responded by saying: “There are citizens who believe nuclear power is necessary. Operating reactors is our responsibility.”

But Kawamura also admitted there is room for only two more years’ worth of space in the tanks to accommodate the contaminated water building up at Fukushima No. 1.

During the meeting the NRA asked Tepco’s management about the company’s safety measures for the Niigata complex — the biggest nuclear power station in the world — as well as its safety awareness.

Tanaka said the NRA does consider Tepco’s responses at the meeting as sufficient and requested that it submit further explanations on its plan to decommission Fukushima No. 1 and resume operation of the two reactors at Kashiwazaki-Kariwa.

Tanaka plans to conduct on-site checkups at the two reactors, saying, “Tepco, which caused the (Fukushima) accident, is not an ordinary operator.”

The two boiling water reactors at the Niigata plant are the same type that suffered core meltdowns at Fukushima No. 1, and no such reactors have cleared the authority’s safety screening since the 2011 crisis.

http://www.japantimes.co.jp/news/2017/07/10/national/japans-nuclear-safety-chief-raps-tepcos-attitude-fukushima-no-1-crisis-restarting-reactors/

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July 10, 2017 Posted by | Fukushima 2017 | , , , , | Leave a comment

Doubts about nuclear plant’s quake resistance

Doubts about nuclear plant’s quake resistance shake trust in NRA

Trust in Japan’s nuclear watchdog, the Nuclear Regulation Authority (NRA), has been jolted. At hand is an issue raised by Kunihiko Shimazaki, former acting chairman of the NRA. Shimazaki pointed out that Kansai Electric Power Co. underestimated the maximum shaking that could occur during an earthquake at its Oi Nuclear Power Plant in Fukui Prefecture.

Shimazaki is an authority on seismology, having formerly served as president of the Seismological Society of Japan. While serving in the NRA, he handled screening of power companies’ earthquake predictions for nuclear power plants including the Oi nuclear plant.

After he stepped down two years ago, he re-examined data and found the method of calculating standard ground motion (the maximum shaking that would occur during an earthquake) was inappropriate in some cases, depending on the type of fault. This could lead power companies to underestimate figures, he apparently found in his research.

If Shimazaki’s argument is correct, the Oi Nuclear Power Plant could come under pressure to provide even greater reinforcement against quakes.

The NRA had for the most part accepted Kansai Electric’s data, but following the claim by Shimazaki, a new calculation on ground motion was performed using a method differing from that adopted by the power company. As the figure was below that presented by Kansai Electric, it determined that the utility had not underestimated the shaking, and during a regular meeting on July 13, it decided against revising Kansai Electric’s figure.

Shimazaki, however, objected, saying that the recalculated figure should have greatly surpassed the original figure for standard ground motion. The reason is that during screening, the outcome of calculations is normally multiplied by 1.5 to provide an added element of safety, but this wasn’t done.

The new calculation was performed by the secretariat of the NRA. A member of the secretariat who talked with Shimazaki admitted that the renewed calculation was repeatedly stretched, and had “no accuracy.” The member added, “It’s not known how much leeway should be given.” It couldn’t be helped if the secretariat were accused of adopting its approach to avoid criticism that the estimate for envisaged damage was too low. The fact that the NRA accepted without questions its secretariat’s explanation that Kansai Electric’s estimate was sufficient raises doubts about its competence.

There are no experts on seismology among the NRA’s five commissioners. NRA Chairman Shunichi Tanaka has expressed the opinion that the calculated figure for standard ground motion at the Oi Nuclear Power Plant doesn’t have to be reviewed. We worry whether quake resistance has been calculated properly.

Shimazaki has suggested to the NRA that it listen to a wide range of opinions from experts in seismology and incorporate the good ones into its screening. Even if experts differ in their evaluations of Shimazaki’s research results, his suggestion to the NRA itself is appropriate.

Tanaka, however, commented, “We don’t have the leeway to do that and it’s not our job to do it either.” We can only be skeptical about such a stance.

The NRA is supposed to be the final fortress in ensuring nuclear safety. We hope that it will try to make improvements to methods of calculating quake resistance of its own accord.

http://mainichi.jp/english/articles/20160725/p2a/00m/0na/006000c

NRA sees no need to review maximum quake estimate at Oi nuke plant

The Nuclear Regulation Authority (NRA) on July 27 concluded that there is no need to review the maximum possible earthquake estimate — known as the standard ground motion — for Kansai Electric Power Co.’s Oi Nuclear Power Plant in Fukui Prefecture.

The NRA reached the conclusion at a regular meeting after former acting NRA chairman Kunihiko Shimazaki pointed out that Kansai Electric had “underestimated” the calculated standard ground motion for its Oi plant. The NRA said that the result of Kansai Electric’s calculation was reasonable. The NRA then dismissed Shimazaki’s argument by saying that calculation methods other than the current one used for the Oi plant “have not reached a degree of scientific and technological maturity.”

Shimazaki had earlier suggested that the so-called “Irikura-Miyake method” used by Kansai Electric was the cause of the underestimated standard ground motion. The NRA’s secretariat checked the validity of other methods such as the “Takemura method,” but it concluded that ways of taking into account the “uncertainties” involved in predicting standard ground motions have not been established. Five NRA commissioners approved the secretariat’s verification results.

A string of issues over the calculations of standard ground motions raised questions about the NRA’s expertise.

After recalculating the estimated standard ground motion for the Oi plant using the “Irikura-Miyake method” — the same method used by Kansai Electric — the NRA secretariat found that the recalculated estimate was 356 gals, “gal” being a unit of acceleration. Its recalculation based on the “Takemura” method showed 644 gals. These two figures fell below Kansai Electric’s estimate of 856 gals. Therefore, the NRA secretariat determined that Kansai Electric’s figure was not “underestimated.” The NRA approved the secretariat’s findings on July 13.

On July 19, the NRA secretariat effectively withdrew its findings, saying that “They were unreasonable calculations.” Thus, it came to light that the NRA had confirmed the secretariat’s findings without verifying the validity of the calculations. It also came to light that the NRA had not grasped the detailed process of Kansai Electric’s calculation as the secretariat’s calculation result conflicted with that of Kansai Electric. The NRA approved Kansai Electric’s calculation of the standard ground motion in the autumn of 2014, but questions were subsequently raised about the way in which the screening was conducted.

Among the five NRA commissioners is a geologist, but there is no expert on ground motion. At a news conference on July 27, NRA Chairman Shunichi Tanaka acknowledged that his group was lacking expertise, saying, “That’s what we need to reflect on.” But when he met Shimazaki on July 19, Tanaka bluntly said, “There is no room for listening to outside experts nor am I in a position to do so.” As the biggest lesson learned from the Fukushima nuclear crisis ought to be that the most up-to-date expertise should be reflected in safety measures, the NRA is urged to listen to arguments and suggestions from outside experts.

http://mainichi.jp/english/articles/20160728/p2a/00m/0na/006000c

July 28, 2016 Posted by | Japan | , , , | Leave a comment

Nuclear regulator OKs additional 20-yr operation for aging reactors

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The Takahama Nuclear Power Plant’s No. 1 and 2 reactors (from left in the front row) and No. 3 and 4 reactors (from left in the back row) are pictured in this photo taken from a Mainichi helicopter in Takahama, Fukui Prefecture, on June 15, 2016.

TOKYO (Kyodo) — Japan’s nuclear regulator on Monday approved an additional 20 years of operation for two aging reactors on the Sea of Japan coast that will become the first such reactors to resume operation under new rules introduced after the Fukushima nuclear meltdown.

The Nuclear Regulation Authority granted its approval of Kansai Electric Power Co.’s plan to continue the operation of its No.1 and No.2 reactors at the Takahama nuclear plant in Fukui Prefecture, both of which are over 40 years old.

The rules, tightened after the 2011 nuclear disaster at Tokyo Electric Power Co.’s Fukushima Daiichi plant, set the maximum length of operation for nuclear reactors at 40 years in principle but also stipulate that their operations can be extended for an additional 20 years if the NRA allows.

Since December 2014, Kansai Electric has been checking on degradation of the two reactors in a stricter manner than regular checkups to obtain approval for extending their operations.

After confirming there were no abnormalities, the utility applied in April last year for an NRA screening.

In order for the reactors to resume operation, the company needed to complete three procedures by July 7. The two reactors had already passed a test for compatibility with the new rules and received approval for a construction plan that detailed equipment design. The only remaining test was for measures against the degradation of the reactors.

In the screening, preventing long electric cables from catching fire and covering the containment vessels with concrete were raised as issues to be addressed, and the company submitted a plan to complete such necessary measures by October 2019.

The reactors are therefore expected to resume operations after these steps have been completed.

The No.1 reactor began operating in November 1974, while the No. 2 reactor did so in November the following year. Both reactors have been suspended since regular checkups in 2011.

http://mainichi.jp/english/articles/20160620/p2g/00m/0dm/070000c

June 20, 2016 Posted by | Japan | , , , | Leave a comment