Japan’s Kansai Electric to shut down 2 major nuclear reactors — Nikkei Asian Review

” OSAKA — Kansai Electric Power Co. has decided to close two large, aging nuclear reactors at a power plant in Fukui Prefecture in light of rising safety costs that make restarting such facilities financially untenable.

The Oi plant’s Nos. 1 and 2 reactors each have an output capacity of 1.18 million kW, making them Japan’s largest to be decommissioned aside from Tokyo Electric Power Co. Holding’s crippled Fukushima Daiichi reactors. Both started operating in 1979. The Osaka-based utility is in talks with Fukui local governments and other parties to make a final decision before winter.

Following the 2011 earthquake and tsunami that caused the Fukushima catastrophe, Japan limited nuclear plants’ operating lifespan to four decades as a general rule. That period can be extended to a maximum of 60 years with the Nuclear Regulation Authority’s approval, but that requires safety investments to the tune of 100 billion yen ($894 million).

Previously, energy companies generally aimed to extend the lifespan of old plants with generation capacities of millions of kilowatts. But with safety costs climbing and energy demand stagnating, turning a profit has grown difficult even at large-scale facilities.

Kansai Electric had already decided to decommission two smaller reactors at its Mihama plant, also in Fukui. Those were among Japan’s six reactors — not including Fukushima Daiichi — with approval to shut down, all with output capacities in the 300,000 kW to 500,000 kW range.

Restarting a planned seven reactors is projected to cost Kansai Electric about 830 billion yen for safety measures. Adding the Oi pair would push the total over 1 trillion yen. Decommissioning a plant takes about 30 years and costs tens of billions of yen, but it is still cheaper than restarting it.

The power company sold around one-fifth less energy in fiscal 2016 than it did in fiscal 2010, as Japanese society grew more energy-conscious following the 2011 disaster and the liberalization of energy retail that led to a loss of customers. Shutting down the two Oi reactors and others will cut the Osaka utility’s generating capacity by around 10%, but with demand also cooling, the reduction is not expected to crimp supply.

Nuclear power now contributes less than 10% of Japan’s energy, down from about 30% before Fukushima. The government’s current plan calls for nuclear power to make up about 20-22% of the total in 2030, far above the present scale.

Japan idled its nuclear plants to make them compliant with tougher safety standards after Fukushima. At present, just five are back online, operated by Kansai Electric, Kyushu Electric Power and Shikoku Electric Power. The government’s target would require having around 30 plants running. But many are more than three decades old, and so will soon either need to be turned off or seek an extension.

If profit concerns force more power companies to go the Osaka utility’s route, Japan’s proportion of nuclear power will remain low, complicating the government’s plan. ”

by Nikkei Asian Review

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Fukushima evacuee to tell UN that Japan violated human rights — The Guardian

” A nuclear evacuee from Fukushima will claim Japan’s government has violated the human rights of people who fled their homes after the 2011 nuclear disaster, in testimony before the UN in Geneva this week.

Mitsuko Sonoda, who voluntarily left her village with her husband and their 10-year-old son days after three reactors at the Fukushima Daiichi nuclear power plant went into meltdown, will tell the UN human rights council that evacuees face financial hardship and are being forced to return to neighbourhoods they believe are still unsafe almost seven years after the disaster.

“We feel abandoned by the Japanese government and society,” Sonoda, who will speak at the council’s pre-session review of Japan on Thursday, told the Guardian.

An estimated 27,000 evacuees who, like Sonoda, were living outside the mandatory evacuation zone when the meltdown occurred, had their housing assistance withdrawn this March, forcing some to consider returning to their former homes despite concerns over radiation levels.

In addition, as the government attempts to rebuild the Fukushima region by reopening decontaminated neighbourhoods that were once no-go areas, tens of thousands of evacuees who were ordered to leave will lose compensation payments and housing assistance in March next year.

The denial of financial aid has left many evacuees facing a near-impossible choice: move back to homes they fear are unsafe, or face more financial hardship as they struggle to build lives elsewhere without state help.

“People should be allowed to choose whether or not to go back to their old homes, and be given the financial means to make that choice,” said Kendra Ulrich, senior global energy campaigner for Greenpeace Japan.

“If they are being put under economic pressure to return, then they are not in a position to make an informed decision. This UN session is about pressuring the Japanese government to do the right thing.”

Evacuees are being encouraged to return to villages and towns near the Fukushima plant despite evidence that some still contain radiation “hot spots”.

In Iitate village, where the evacuation order was lifted this March, much of the surrounding forests remain highly radioactive, although homes, schools and other public buildings have been declared safe as part of an unprecedented decontamination effort.

“You could call places like Iitate an open-air prison,” said Ulrich. “The impact on people’s quality of life will be severe if they move back. Their lives are embedded in forests, yet the environment means they will not be allowed to enter them. Forests are impossible to decontaminate.”

After months of moving around, Sonoda and her family settled in Kyoto for two years, where local authorities provided them with a rent-free apartment. They have been living in her husband’s native England for the past four years.

“We’ve effectively had to evacuate twice,” said Sonoda, who works as a freelance translator and Japanese calligraphy tutor. “My son and I really struggled at first … we didn’t want to leave Japan.”

Concern over food safety and internal radiation exposure convinced her that she could never return to Fukushima, aside from making short visits to see relatives. “It’s really sad, because my village is such a beautiful place,” she said. “We had a house and had planned to retire there.”

The evacuations have forced families to live apart, while parents struggle to earn enough money to fund their new accommodation and keep up mortgage payments on their abandoned homes.

“Stopping housing support earlier this year was an act of cruelty,” Sonoda said. “Some of my friends had to go back to Fukushima even though they didn’t want to.”

Greenpeace Japan, which is assisting Sonoda, hopes her testimony will be the first step in building international pressure on Japan’s government to continue offering financial help to evacuees and to reconsider its resettlement plan.

It has called on the government to declare Fukushima neighbourhoods unsafe until atmospheric radiation is brought to below one millisievert (mSv) a year, the maximum public exposure limit recommended by the International Commission on Radiological Protection.

While 1 mSv a year remains the government’s long-term target, it is encouraging people to return to areas where radiation levels are below 20 mSv a year, an annual exposure limit that, internationally, applies to nuclear power plant workers.

“Why should people, especially women and children, have to live in places where the radiation level is 20 times the international limit?” Sonoda said. “The government hasn’t given us an answer.” ”

by The Guardian

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Fukushima court rules Tepco, government liable over 2011 disaster — Reuters

” TOKYO (Reuters) – A district court in Fukushima prefecture on Tuesday ruled that Tokyo Electric Power and the Japanese government were liable for damages totaling about 500 million yen ($4.44 million) in the largest class action lawsuit brought over the 2011 nuclear disaster, Kyodo news agency said.

A group of about 3,800 people, mostly in Fukushima prefecture, filed the class action suit, marking the biggest number of plaintiffs out of about 30 similar class action lawsuits filed across the nation.

This is the second court ruling that fixed the government’s responsibility after a Maebashi district court decision in March.

All the three district court decisions so far have ordered Tepco to pay damages. Only the Chiba court decision last month did not find the government liable for compensation.

The plaintiffs in Fukushima case have called on defendants for reinstating the levels of radioactivity at their homes before the disaster, but the court rejected the request, Kyodo said.

Tepco has long been criticized for ignoring the threat posed by natural disasters to the Fukushima plant and the company and the government were lambasted for their handling of the crisis. “

reporting by Osamu Tsukimori and Aaron Sheldrick; editing by Christian Schmollinger and Gopakumar Warrier, Reuters

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Muons suggest location of fuel in unit 3 — World Nuclear News

” Some of the fuel in the damaged unit 3 of the Fukushima Daiichi plant has melted and dropped into the primary containment vessel, initial results from using a muon detection system indicate. Part of the fuel, however, is believed to remain in the reactor pressure vessel.

Muons are high-energy subatomic particles that are created when cosmic rays enter Earth’s upper atmosphere. These particles naturally and harmlessly strike the Earth’s surface at a rate of some 10,000 muons per square meter per minute. Muon tracking devices detect and track these particles as they pass through objects. Subtle changes in the trajectory of the muons as they penetrate materials and change in direction correlate with material density. Nuclear materials such as uranium and plutonium are very dense and are therefore relatively easy to identify. The muon detection system uses the so-called permeation method to measure the muon data.

Tokyo Electric Power Company (Tepco) installed a muon detection system on the first floor of unit 3’s turbine building. Measurements were taken between May and September this year.

Tepco said analysis of muon examinations of the fuel debris shows that most of the fuel has melted and dropped from its original position within the core.

Prior to the 2011 accident, some 160 tonnes of fuel rods and about 15 tonnes of control rods were located within the reactor core of unit 3. The upper and lower parts of the reactor vessel contains about 35 tonnes and 80 tonnes of structures, respectively.

The muon examination indicates that most of the debris – some 160 tonnes – had fallen to the bottom of the reactor pressure vessel and resolidified, with only about 30 tonnes remaining in the reactor core. Tepco said another 90 tonnes of debris remains in the upper part of the vessel.

The bulk of the fuel and structures in the core area dropped to the bottom of the reactor pressure vessel (RPV), Tepco believes. While part of the molten fuel is understood to have then fallen into the primary containment vessel (PCV), “there is a possibility that some fuel debris remains in the bottom of the RPV, though this is uncertain”, the company noted.

Similar muon measurements have already been conducted at units 1 and 2 at Fukushima Daiichi. Measurements taken at unit 1 between February and September 2015 indicated most of the fuel was no longer in the reactor’s core area. Measurements taken between March and July 2016 at unit 2 showed high-density materials, considered to be fuel debris, in the lower area of the RPV. Tepco said that more fuel debris may have fallen into the PCV in unit 3 than in unit 2.

Tepco said the results obtained from the muon measurements together with knowledge obtained from internal investigations of the primary containment vessels using remote-controlled robots will help it plan the future removal of fuel debris from the damaged units. ”

by World Nuclear News

source with illustration of Unit 1-3

Botched gauge settings might have contaminated Fukushima groundwater from April onward: Tepco — The Japan Times

” The discovery of falsely configured monitoring equipment at the stricken Fukushima No. 1 nuclear power plant means the groundwater flowing underneath it might have gotten contaminated from April onward, Tokyo Electric said Friday.

The utility said incorrect gauge settings were used to measure groundwater levels in six of the wells near reactors 1 and 4. This resulted in groundwater readings about 70 cm higher than reality, which means the beleaguered power utility has been mismanaging the groundwater there for months.

To prevent tainted water from leaking from the plant, Tokyo Electric Power Company Holdings Inc. installed water gauges so it could keep the groundwater levels in the wells a meter higher than the contaminated water in the buildings.

Tepco adjusts the amount of water in wells called subdrains around the buildings to keep the groundwater higher than the tainted water inside them, which prevents it from flowing out. If the groundwater levels sink below the level of the radioactive water, it might leak out.

On Friday, Tepco said the estimated groundwater level in one of the six subdrain wells close to reactor 1 fell below the level in the reactor building at least eight times during the five-day period to May 21 because the gauges were set incorrectly.

Groundwater levels were 2 mm to 19 mm lower than the level in the buildings, Tepco said, adding that it does not know precisely how long each of these problematic situations lasted because water level data is collected by the hour.

Tepco said groundwater levels in five other wells affected by the incorrect settings did not fall below the levels in the nearby reactor buildings.

All six are in the area surrounded by an underground ice wall designed to prevent groundwater leakage.

According to Tepco, the incorrect settings date as far back as April 19. The earliest error affected the gauge in a well where groundwater fell to hazardous levels.

In the world’s worst nuclear disaster since Chernobyl, reactors 1, 2 and 3 at the plant experienced core meltdowns and reactors 1, 3 and 4 were severely damaged by hydrogen explosions following a massive offshore earthquake that spawned large tsunami in March 2011. ”

by Jiji, Kyodo via The Japan Times

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Fukushima’s decommissioning delays, challenges and unknowns remain roadblocks to cleanup — Beyond Nuclear

” Six and a half years after the Fukushima Daiichi triple meltdown, Japan’s government, the nuclear regulator and Tokyo Electric Power Company’s (TEPCO) most rudimentary plan of attack for recovery from radioactive catastrophe is delayed again. The first steps of decommissioning cannot legitimately begin until undamaged but highly radioactive “spent” fuel assemblies are removed from vulnerable reactor storage ponds, sufficiently cooled and re-contained in qualified dry storage casks.  Then, there are the three melted fuel cores that still must be located, retrieved and somehow re-contained. Where all of the massive radioactive contamination will go is a mystery.  In fact, there are an alarming number of challenges, continuing delays and unknowns that remain before securing the destroyed nuclear power station site and halting the ongoing release of radioactivity to the land, water and air.

Among the most immediate concerns is the management of 1007 highly radioactive and thermally hot irradiated nuclear fuel assemblies still in the two cooling pools perched atop the destroyed Units 1 and 2 outside of any containment structure. Each of the site’s six-units has an elevated nuclear waste storage pond. The site has a large common pool located near Unit 4. The government recently admitted that previously unknown, possibly undisclosed, damage in these irradiated fuel storage ponds and radioactive contamination has again delayed the plan to move the dangerous fuel assemblies by at least another three years, now 2023. Unit 3 remains on schedule in 2018 to begin the two-year transfer of 514 irradiated fuel assemblies from its rooftop storage pool to a jam-packed common onsite pool located at ground level. This common pool and its massive radioactive inventory requires reliable cooling power.  Unit 4 completed a three-year project to transfer its irradiated fuel into the common pool in 2014. The common pool now has 6,726 irrradiated fuel assemblies with a maximum design capacity of 6,840. As this common pool is already densely packed, it is ever more critical that Japan expedite the transfer of the sufficiently cooled irradiated nuclear fuel into qualified, individualized dry storage casks that can passively cool the hot nuclear waste without the need for water and electrical power. Currently, only 1,412 irradiated assemblies have been secured in onsite dry cask storage. These dry casks further need to be hardened against another natural disaster and possible terrorism.

The recurring delays at securing the irradiated fuel currently in wet pool storage (individual units to the common pool) and then into scientifically-qualified and hardened dry cask storage systems raises concern for public health, safety and the environment given the prospect of another large nearby earthquake causing a loss of cooling with the risk of a nuclear waste fire and radioactive releases. A 6.9 magnitude offshore earthquake on November 21, 2016 caused a temporary loss of cooling to wet storage systems at Fukushima Daiichi. Significant earthquakes of 6.0 to 6.9 magnitude occur in Japan on average 17 times per year, roughly one-tenth of all large earthquakes in the world. More severe earthquakes must be anticipated. The loss of cooling power and water to some or all of the more than 11,577 hot nuclear waste assemblies onsite outside of containment remains a significant public health, safety and environmental concern.

Japan is still technologically conceptualizing the “most challenging part” of Fukushima Daiichi’s decommissioning and the recovery of three missing melted reactor cores if and when they can be located. The unprecedented operation has now been delayed until 2019.  A viable technology for scooping up melted nuclear fuel does not yet exist. Re-containment and removal of the melted fuel cores is key to addressing the ongoing massive buildup of radioactive water now estimated at 800,000 tons that is being stored in growing onsite tank farms.  Groundwater flowing down into the reactor wreckage must be constantly pumped out, partially filtered of radioactivity and stored onsite in the large tanks. The tank farms themselves represent an additional environmental threat in the event of another severe earthquake that could rupture the structures with a radioactive flood into the ocean. ”

by Beyond Nuclear

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