Japan’s nuclear watchdog chief holds final press conference before stepping down

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Nuclear Regulation Authority (NRA) Chairman Shunichi Tanaka held his final press conference in Tokyo’s Minato Ward on Sept. 20 before officially stepping down from his role.

Reflecting on his five-year term in office, Tanaka said, “I tried to maintain independence and transparency,” adding that, “I have absolutely no doubt that I’ve made judgments from a scientific and impartial standpoint, and taken actions based on (the NRA’s) philosophies. This is something that I am proud of.”

However, he also stated that, “The distrust of the public who experienced the Fukushima nuclear disaster in 2011 is an issue that cannot be easily rectified.”

Tanaka became the first chairman of the NRA at the same time the organization was established in September 2012, having previously served as the deputy director general of the Japan Atomic Energy Research Institute and acting chairman of the Japan Atomic Energy Commission.

During his time as NRA chairman, he led efforts to draw up new regulatory standards based on the lessons learned from the Tokyo Electric Power Co.’s Fukushima No. 1 Nuclear Power Plant disaster, and carried out nuclear power plant screening.

Originally hailing from Fukushima Prefecture, Tanaka says he is planning to live in the prefectural village of Iitate after stepping down as NRA head. “It would be great if I could contribute to the recovery of Fukushima (using my experience at the NRA),” Tanaka said.

https://mainichi.jp/english/articles/20170921/p2a/00m/0na/004000c

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Nuclear regulator defers giving safety OK for idle Tepco reactors at Kashiwazaki-Kariwa plant

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TOKYO (Kyodo) — Japan’s nuclear safety watchdog on Wednesday deferred giving safety clearance for two idle Tokyo Electric Power Company Holdings Inc. reactors on the Sea of Japan coast, although its chairman said the utility was “qualified” as a nuclear plant operator.

Nuclear Regulation Authority Chairman Shunichi Tanaka said following Wednesday’s meeting that Tepco, operator of the crippled Fukushima Daiichi nuclear power plant, was qualified but needs to stipulate its resolve to ensure safe operation of nuclear plants in its safety rules.

“It’s insecure” if Tepco expresses its resolve to ensure safety only in words, Tanaka told a press conference.

Safety rules need to be approved by the regulator and if there is a grave violation the regulator can demand that the utility halt nuclear power operations.

The regulator will formally inform the utility’s president, Tomoaki Kobayakawa, about the matter on Sept. 20. A final decision on whether Tepco is fit to be an operator will be made following discussions with the economy, trade and industry minister.

If Tepco agrees to include its resolve to ensure safety in its safety rules, the regulator will compile a draft document for the Nos. 6 and 7 reactors at Tepco’s Kashiwazaki-Kariwa plant in Niigata Prefecture that will serve as certification that the utility has satisfied new safety requirements implemented since the 2011 Fukushima nuclear disaster.

The regulator had been expected at Wednesday’s meeting to confirm that the units have cleared the new safety requirements, but it reversed course after facing criticism over a lack of debate on whether the operator is fit to run a nuclear power plant.

For a reactor to be restarted, it first needs to clear the stiffer safety requirements introduced in the wake of the Fukushima nuclear crisis, which was triggered by a massive earthquake and tsunami on March 11, 2011. Tepco filed for safety assessments of the two units in September 2013.

According to sources close to the matter, the regulator had planned to give safety clearance while Tanaka was still on the board. Tanaka’s term expires on Sept. 18, although he will continue to work until Sept. 22.

The regulator had reached a near consensus on the issue of Tepco’s qualification when its members previously met on Sept. 6.

During the summer, the regulator questioned the Tepco management, including Kobayakawa, about its nuclear safety awareness. In July, Tanaka criticized Tepco’s attitude, saying, “An operator, which cannot take concrete measures for decommissioning efforts at the Fukushima Daiichi power plant, does not have the right to resume operation of nuclear reactors.”

Tanaka urged the utility to further explain in writing issues such as how to deal with contaminated water at the Fukushima plant.

While Tepco, in its subsequent written response, did not give details about what it would do regarding the contaminated water, it did pledge to see through the scrapping of the plant, gaining a certain level of understanding from the regulator.

Meanwhile, the prospect of gaining local consent needed for the restart of the two reactors remains uncertain, with Niigata Gov. Ryuichi Yoneyama saying it will take “around three to four years” for the utility to win local consent for the envisioned restart.

http://mainichi.jp/english/articles/20170914/p2g/00m/0dm/006000c

 

 

Tepco’s makes error in Kashiwazaki-Kariwa nuclear plant’s quake proof tests

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TEPCO admits error in screening report

Japan’s Nuclear Regulation Authority is demanding an explanation from Tokyo Electric Power Company.
TEPCO has admitted to submitting inaccurate information from calculations 3 years ago on plans for restarting two of its nuclear reactors in Niigata Prefecture.
The regulator is in the final stages of screening the No.6 and 7 reactors at TEPCO’s Kashiwazaki-Kariwa plant.
The reactors must meet new government requirements introduced after the 2011 Fukushima disaster.
Regulators gathered on Tuesday for discussions with TEPCO about buildings at the plant to be used as headquarters in an emergency.
TEPCO officials admitted one of the buildings lacked the necessary quake-resistance in all 7 of the company’s tests.
They had earlier said that the building had failed 5 of the 7 tests. They said they would not use the building.
They blamed the discrepancy on a failure by the civil engineering department to convey test results to the equipment design department.
The regulators noted the lack of coordination between TEPCO departments on the impact of soil liquefaction on breakwaters.
They called the mistakes unacceptable, and they’re demanding that TEPCO provide details and countermeasures.

https://www3.nhk.or.jp/nhkworld/en/news/20170215_18/

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Kashiwazaki Mayor Masahiro Sakurai, center, visiting the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture during an emergency drill in December. He is briefed by plant chief Chikashi Shitara, right

 

Key Niigata nuclear plant building may not be quake-proof

Tokyo Electric Power Co. has revealed that a key building at its Kashiwazaki-Kariwa nuclear power plant may not be able to withstand even half of the assumed strongest seismic shaking, contrary to its earlier assurances.

TEPCO’s disclosure came Feb. 14 during a screening by the Nuclear Regulation Authority (NRA) for the restart of the No. 6 and No. 7 reactors at the nuclear power plant in Niigata Prefecture, which is the world’s largest.

The utility became aware of the possibility in 2014, but the information was not shared within the company. TEPCO reported to the NRA that the building can withstand temblors of 7, the highest category on the Japanese seismic intensity scale.

The building is designed to serve as an on-site emergency headquarters in the event of a severe accident, such as one caused by an earthquake.

An earthquake that occurred off the Chuetsu region of Niigata Prefecture in 2007 badly damaged the Kashiwazaki-Kariwa plant.

In response, TEPCO constructed the building in question in 2009. At that time, it said the structure could withstand the assumed biggest earthquake motions that are 1.5 times stronger than those described in the Building Standards Law.

In 2014, the utility checked the building’s anti-quake capabilities again. It found that it may not be able to withstand horizontal movements triggered by even half the anticipated strongest earthquake, and that it could collapse into the side of an adjacent building.

That information was not conveyed to the company’s division in charge of the NRA’s screening, and thus escaped notice from NRA inspections.

Takafumi Anegawa, managing executive officer of TEPCO, apologized, saying, “We did not conceal the possibility. The in-house liaison was insufficient.”

An NRA official said, “Information is not shared in the company. Lessons from the accident at the Fukushima No. 1 nuclear power plant are not utilized.”

http://www.asahi.com/ajw/articles/AJ201702150042.html

Kashiwazaki Mayor Masahiro Sakurai, center, visiting the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture during an emergency drill in December. He is briefed by plant chief Chikashi Shitara, right

NRA pushing dry cask storage, not pools, for spent nuclear fuel

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Japan’s nuclear watchdog will ease quake-related and other regulations on storing spent fuel to push the use of dry casks and reduce the dangers stemming from power failures at nuclear power plants.

The Nuclear Regulation Authority decided on Jan. 25 that utilities should place spent nuclear fuel in the special air cooling containers instead of the common practice of submerging the fuel rods in pools of water.

Fuel stored in pools is cooled by circulating water with pumps, but the system can shut down if earthquakes and other disasters cut off the power supply. The water could then evaporate, leaving the spent fuel and radioactive substances exposed to air.

Electric power companies have shown a positive attitude toward the dry storage system because it would enable them to keep more spent fuel when the pools are filled close to capacity.

However, municipalities that host nuclear power plants have expressed strong concerns that the system will let utilities keep spent nuclear fuel at plant sites for prolonged periods.

NRA Chairman Shunichi Tanaka stressed the need for safety.

It (dry cask storage) is much safer than storing fuel in pools,” he said.

The Great East Japan Earthquake and tsunami cut off power to Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant in March 2011. Three reactors melted down, and the cooling system would not work for more than 1,000 spent fuel assemblies in the pool in the No. 4 reactor building.

Fears arose that all water in the pool could evaporate. But emergency measures, including the pumping in of water, were taken to keep the fuel submerged.

Under the dry storage system, the fuel is sufficiently cooled in pools and placed in dedicated airtight cases. The special casks are then stored inside air-permeable facilities.

The NRA plans to promote use of casks that are currently used to transport spent nuclear fuel.

The containers have passed durability tests and can withstand falls from a height of 9 meters and high-temperature fires.

Dry storage containers are widely used in the United States and Europe.

But the use of dry casks has not spread in Japan because of the high hurdles that must be cleared. One requirement is that those containers must be stored in building that can withstand the strongest earthquake predicted in the area.

As a result, dry storage containers are used at only a few nuclear facilities in the country, such as Japan Atomic Power Co.’s Tokai No. 2 nuclear power plant in Ibaraki Prefecture.

According to the Federation of Electric Power Companies of Japan, a total of 15,000 tons of spent fuel is stored at 17 nuclear plants across Japan.

Seventy percent of their fuel pools and other storage facilities have been filled with spent fuel.

http://www.asahi.com/ajw/articles/AJ201702140004.html

NRA clears Genkai reactors

The R3 and R4 of the Genkai nuclear power plant, Pref. Saga, have met the new safety standards of the NRA. Restart announced at the end of summer.

As of today: Have met the safety standards, 10 reactors in 5 nuclear plant namely also Sendai R1, R2 – Takahama R1 to R4 – Mihama R3 – Ikata R3.

Two reactors have now been restarted: Sendai 1 and Ikata 3 (using MOX).

 

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The Nuclear Regulation Authority formally decided Wednesday on the screening document certifying that the Nos. 3 and 4 reactors at Kyushu Electric Power Co.’s Genkai nuclear power plant in Saga Prefecture satisfied the country’s safety standards for their restart.

The latest decision made at an NRA regular meeting brings to 10 the number of reactors, at five nuclear power plants, that have satisfied the regulator’s new safety standards, introduced after the nuclear disaster at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 nuclear power plant in 2011. The two Genkai reactors are scheduled to be back online sometime in or after summer this year.

The Kyushu power company applied for a safety screening on those reactors in July 2013. At that time, the company anticipated an earthquake with an acceleration of up to 540 gal at the Genkai plant followed by tsunami of up to 3 meters high. However, the NRA deemed the simulation as “too optimistic” and the figures were raised to an acceleration of 620 gal with 4-meter-high tsunami.

In November last year, the NRA approved a draft document as the two reactors complied with the new standards. The NRA then solicited public opinions and received 4,200 comments, including concerns over possible earthquakes, but concluded that there was no problem with compliance.

With the formal decision being made on the Genkai plant, the focus for the restart has moved to an approval of a construction plan that maps out the specifications of related equipment for safe operation as well as whether it can obtain the consent of local governments for the restart.

So far, nuclear reactors that have passed the NRA’s screenings under the new standards are the Nos. 1 and 2 reactors at Kyushu’s Sendai power plant in Kagoshima Prefecture, the Nos. 1 to 4 reactors at Kansai Electric Power Co.’s Takahama plant and KEPCO’s No. 3 reactor at Mihama plant, both in Fukui Prefecture, and the No. 3 reactor at Shikoku Electric Power Co.’s Ikata plant in Ehime Prefecture. Currently, two reactors — Sendai plant’s No. 1 and Ikata’s No. 3 — are online.

http://www.the-japan-news.com/news/article/0003466628

 

 

 

Another operation approval of aging nuclear reactor contradicts 40-year rule

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The No. 3 reactor of the Mihama Nuclear Power Station in Mihama, Fukui Prefecture, is pictured in this photo taken from a Mainichi Shimbun helicopter on Nov. 12, 2016.

 

Another operation approval of aging nuclear reactor contradicts 40-year rule

The Nuclear Regulation Authority (NRA) has allowed Kansai Electric Power Co. to continue running the No. 3 reactor at its Mihama Nuclear Power Station in Fukui Prefecture beyond the 40-year limit.
This is the third nuclear reactor in the country that will have been allowed to continue to operate beyond the 40-year limit — following the No. 1 and 2 reactors at the Takahama plant also in Fukui Prefecture.

The move contradicts rules stipulating that nuclear reactors should be decommissioned after being operated for 40 years, in principle.

It had been viewed as extremely difficult to extend the lifespan of Mihama’s No. 3 reactor because of its old design and difficulties in improving the reactor’s quake resistance as the plant operator is required to largely increase the estimate of the scale of the maximum earthquake that could hit the plant.

As such, the NRA once hinted that it would discontinue examinations of the reactor to see if it meets the new regulatory standards.

However, Kansai Electric Power spent 165 billion yen on measures to enhance the safety of the reactor. The NRA increased its personnel to accelerate the examination of the plant, and managed to approve the continuation of its operation by the deadline.

Six aging nuclear reactors across the country are set to be shut down and decommissioned. Their operators voluntarily decided to decommission these reactors, whose outputs are small, considering the units’ cost-benefit performance.

However, if power companies apply for permission to extend the lifespan of nuclear reactors, the NRA will almost certainly grant permission.

The rules limiting the operation of a nuclear reactor to 40 years, in principle, was established with the aim of reducing Japan’s reliance on atomic power stations following the outbreak of the Fukushima nuclear crisis in March 2011. Both the NRA and power companies should go back to the fundamentals of the rules.

http://mainichi.jp/english/articles/20161116/p2a/00m/0na/019000c

Operation extension approved for Mihama reactor

Japan’s nuclear regulator has said an aging reactor will be allowed to operate beyond its 40-year maximum life span.

The No.3 reactor at the Mihama nuclear power plant, on the Sea of Japan coast, has been given a 20-year extension. The Nuclear Regulation Authority made the unanimous decision on Wednesday.

The reactor, in Fukui Prefecture, went offline in March 2011 for a regular checkup and has not been restarted.

The Mihama reactor turns 40 years old later this year, and it will now be permitted to run until November 2036.

The Nuclear Regulation Authority heard evidence on Wednesday that the reactor’s pipes and electric cables are expected to meet required standards for up to 60 years since operations began in 1976.

Some members referred to a 2004 accident at the reactor in which 5 workers were killed after high-temperature steam leaked from a damaged pipe. They urged the operator, Kansai Electric Power Company, to keep checking for possible decay to the facility.

The reactor is the third in Japan to be granted an extension, after 2 reactors at the nearby Takahama plant were approved for restarts in June.

Kansai Electric said it will not restart operations until additional safety work has been completed, by March 2020 at the earliest. It said it believes the restart will be economically practical.

http://www3.nhk.or.jp/nhkworld/en/news/20161116_18/

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Nuclear authority method may underestimate quake sizes: study

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This May 2016 photo shows the stone wall of Kumamoto Castle that was damaged by the April earthquake.

A technique that estimates the scale of earthquakes announced by the Earthquake Research Committee in 2006 may be underestimating the size of earthquakes — a problem for the Nuclear Regulation Authority, which bases its earthquake resistance plans on the system.

Professor Kazuki Koketsu presented the results of his evaluation of the 2006 system at a research session of The Seismological Society of Japan on Oct. 5. Koketsu is a professor at the Earthquake Research Institute at The University of Tokyo and the head of the Subcommittee for Evaluation of Strong Ground Motion, part of the Earthquake Research Committee.

Koketsu compared the estimations of the 2006 technique and a 2009 method to the actual observed data from the magnitude 7.3 Kumamoto Earthquake in April.

While the 2009 technique predicted a magnitude of 7.0 to 7.2 for the active fault, the 2006 technique underestimated the possible magnitude as between 6.6 and 6.9. Koketsu concluded that the 2009 technique is more appropriate for estimating the scale of earthquakes.

However, the Nuclear Regulation Authority (NRA) still uses the estimates of the strongest possible tremor made by the 2006 system as the basis for examining earthquake resistance design plans for nuclear reactors.

In response to Koketsu’s presentation, a representative of the NRA stated at a press conference held on Oct. 5., “We will begin discussion over whether we should adopt the 2009 system after the Subcommittee for Evaluation of Strong Ground Motion has coordinated its views on the matter.”

The 2006 technique bases its estimates on both the estimated length and breadth of active faults. In 2009, the Earthquake Research Committee released a new system based mainly on the length of faults in order to calculate the expected magnitude of quakes on as many active faults as possible in a short amount of time. In Koketsu’s study, the 2006 system miscalculated the length and width of the faults involved in the Kumamoto earthquake, leading to the underestimation of the scale.

While both techniques appear side by side in the research committee’s manual, the committee’s national earthquake scale prediction map for quakes measuring at least lower-6 on the 7-point Japanese intensity scale estimated to occur within the next 30 years along active faults are all calculated using the 2009 system.

http://mainichi.jp/english/articles/20161006/p2a/00m/0na/012000c