NRA slows plan to reuse contaminated soil — SimplyInfo.org

” Japan’s Environment Ministry had a plan. They were going to solve the problem of the massive piles of radioactive soil but reusing it. One plan they described was using it as the base in roads. They didn’t provide much detail on how this would work or how it would not end up leaching contamination to the wider environment.

Japan’s nuclear regulator (NRA) is required to review any act by another agency that involves radiation exposures to the public. Now the NRA has requested a detailed plan before any review would begin. They want details about how this soil would be prevented from being used in residential areas or where children would be exposed.

This may have effectively put a stop to the Environment Ministry plan. Their goal appeared to be to declassify large amounts of contaminated soil and just make it go away however possible. NRA’s requirements may be too inconvenient to continue with that plan. ”

by SimplyInfo.org

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NRA puts stop to plan to reuse contaminated soil — SimplyInfo.org

” Japan’s Environment Ministry had a plan. They were going to solve the problem of the massive piles of radioactive soil but reusing it. One plan they described was using it as the base in roads. They didn’t provide much detail on how this would work or how it would not end up leaching contamination to the wider environment.

Japan’s nuclear regulator (NRA) is required to review any act by another agency that involves radiation exposures to the public. Now the NRA has requested a detailed plan before any review would begin. They want details about how this soil would be prevented from being used in residential areas or where children would be exposed.

This may have effectively put a stop to the Environment Ministry plan. Their goal appeared to be to declassify large amounts of contaminated soil and just make it go away however possible. NRA’s requirements may be too inconvenient to continue with that plan. ”

by Nancy Foust, SimplyInfo.org

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NRA: Ice wall effects ‘limited’ at Fukushima nuclear plant — The Asahi Shimbun

” Citing “limited, if any effects,” the Nuclear Regulation Authority said a highly touted “frozen soil wall” should be relegated to a secondary role in reducing contaminated groundwater at the Fukushima No. 1 nuclear plant.

The government spent 34.5 billion yen ($292 million) to build the underground ice wall to prevent groundwater from mixing with radioactive water in four reactor buildings at the crippled plant.

But the NRA, Japan’s nuclear watchdog, concluded on Dec. 26 that the wall has been ineffective in diverting the water away from the buildings. It said that despite the low rainfall over the past several months, the amount of groundwater pumped up through wells outside the frozen wall on the seaside is still well above the reduction target.

It urged the plant operator, Tokyo Electric Power Co., to tackle the groundwater problem primarily with pumps, not the ice wall.

In response, TEPCO at the meeting said that by next autumn, it will double its capacity to pump up groundwater from the current 800 tons a day.

About 400 tons of groundwater enters the damaged reactor buildings each day and mixes with highly radioactive water used to cool melted nuclear fuel.

The ice wall project, compiled by the industry ministry in May 2013, was seen as a fundamental solution to this problem that has hampered TEPCO’s cleanup efforts since the triple meltdown in March 2011.

Some 1,568 frozen ducts were inserted 30 meters deep into the ground to circulate a liquid at 30 degrees below zero. The freezing process was supposed to have created a solid wall of ice that could block the groundwater.

TEPCO began freezing the wall on the seaside in March. It announced in the middle of October that the temperature at all measuring points in that area was below zero.

Before the frozen wall project, TEPCO had to pump up about 300 tons of contaminated water a day. The daily volume dropped to about 130 tons in recent weeks, but it was still well beyond the target of 70 tons.

Still, TEPCO boasted about the effectiveness of the ice wall at the meeting with the NRA on Dec. 26, saying, “We are seeing certain results.”

The NRA, however, said the results are limited at best.

Toyoshi Fuketa, an NRA commissioner, already warned TEPCO in October that it cannot expect the ice wall to be highly effective in containing the groundwater.

“Pumping up groundwater through wells should be the main player because it can reliably control the groundwater level,” Fuketa said at that time. “The ice wall will play a supporting role.”

That sentiment was echoed at the Dec. 26 meeting.

However, the NRA approved the utility’s plan to begin freezing dirt for a wall on the mountain side of the nuclear plant.

The NRA was previously concerned about risks posed by the new ice wall. If it totally blocked groundwater from the mountain side, the water level within the frozen soil near the reactors could become too low, allowing highly contaminated water inside the reactor buildings to flow out more rapidly.

The NRA urged TEPCO to delay work on the mountain side until the ice wall on the seaside portion proved effective.

But it reversed its stance, saying a sharp drop in the groundwater level is unlikely based on the ineffectiveness of the existing ice wall.

“The frozen wall on the mountain side will not be able to block groundwater because the wall on the seaside was also unable to do so,” Fuketa said. “It will not be very dangerous to freeze the wall on the mountain side as long as the work is carried out carefully.”

TEPCO will start the work to freeze the ducts at five sections as early as next year.

Masashi Kamon, professor emeritus of geotechniques at Kyoto University, expressed skepticism about continuing the ice wall project without a full scrutiny of the underground conditions.

“Soil around the tunnels for underground pipes must be hard to freeze,” he said. “TEPCO should find out the conditions of the very bottom of the ice wall by drilling at least one section. It is questionable to continue with the project without a review.” ”

by Kohei Tomida

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Fukushima aftershock renews public concern about restarting Kansai’s aging nuclear reactors — The Japan Times

” KYOTO – The magnitude-7.4 aftershock that rocked Fukushima Prefecture and its vicinity last week, more than five years after the mega-quake and tsunami of March 2011, triggered fresh nuclear concerns in the Kansai region, which hosts Kansai Electric Power Co.’s Mihama plant in Fukui Prefecture.

The aftershock came as the Nuclear Regulation Authority approved a two-decade extension for Mihama’s No. 3 reactor on Nov. 16, allowing it and two others that have already been approved to run for as long as 60 years to provide electricity to the Kansai region.

Residents need to live with the fact that they are close to the Fukui reactors, which are at least 40 years old. Despite reassurances by Kepco, its operator, and the nuclear watchdog, worries remain over what would happen if an earthquake similar to the one in 2011, or even last week, hit the Kansai region.

Kyoto lies about 60 km and Osaka about 110 km from the old Fukui plants. Lake Biwa, which provides water to about 13 million people, is less than 60 km away.

In addition to Kepco’s 40-year-old Mihama No. 3, reactors 1 and 2 at the Takahama nuclear power plant in Fukui are 42 and 41 years old, respectively.

In the event of an accident, evacuation procedures for about 253,000 residents of Fukui, Shiga, and Kyoto prefectures who are within 30 km of the plants would go into effect.

But how effective might they be?

The majority does not live in Fukui. Just over half, or 128,500, live in neighboring Kyoto, especially in and around the port city of Maizuru, home to a Self-Defense Forces base. Another 67,000 live in four towns in Fukui and about 58,000 live in northern Shiga Prefecture.

Plans call for Fukui and Kyoto prefecture residents to evacuate to 29 cities and 12 towns in Hyogo Prefecture and, if facilities there are overwhelmed, to Tokushima Prefecture in Shikoku. Those in Shiga are supposed to evacuate to cities and towns in Osaka Prefecture.

In a scenario put together by Kyoto Prefecture three years ago, it was predicted that tens of thousands of people would take to available roads in the event of an nuclear accident. A 100 percent evacuation of everyone within 30 km of a stricken Fukui plant was estimated to take between 15 and 29 hours, depending on how much damage there was to the transportation infrastructure.

But Kansai-based anti-nuclear activists have criticized local evacuation plans as being unrealistic for several reasons.

First, they note that the region around the plants gets a lot of snow in the winter, which could render roads, even if still intact after a quake or other disaster, much more difficult to navigate, slowing evacuations even further.

Second is the radiation screening process that has been announced in official local plans drawn up by Kyoto and Hyogo prefectures.

While automobiles would be stopped at various checkpoints along the roads leading out of Fukui and given radiation tests, those inside would not be tested if the vehicle itself has radiation levels below the standard.

If the radiation is above standard, one person, a “representative” of everyone in the car, would be checked and, if approved, the car would be allowed to continue on its way under the assumption that the others had also been exposed to levels below standard. This policy stands even if those levels might be more dangerous to children than adults.

Finally, there is the question of whether bus drivers would cooperate by going in and out of radioactive zones to help those who lack quick access to a car, especially senior citizens in need of assistance.

None of the concerns about the evacuation plans is new, and most have been pointed out by safety experts, medical professionals and anti-nuclear groups.

But with the NRA having approved restarts for three Kansai-area reactors that are over 40 years old, Kansai leaders are responding more cautiously to efforts to restart Mihama No. 3 in particular.

“It is absolutely crucial that local understanding for Mihama’s restart be obtained,” said pro-nuclear Fukui Gov. Issei Nishikawa in July, after a local newspaper survey showed that only about 37 percent of Fukui residents agree with the decision to restart old reactors.

Shiga Gov. Taizo Mikazuki, who is generally against nuclear power, was even more critical of the NRA’s decision to restart Mihama.

“There are major doubts about the law that regulates the use of nuclear reactors more than 40 years old. The central government and Kepco need to explain safety countermeasures to residents who are uneasy. People are extremely uneasy about continuing to run old reactors,” the governor said earlier this month. ”

by Eric Johnston

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Scrapping of Monju would mean disposal of 760 tons of radioactive sodium, MOX fuel — The Japan Times

” About 760 tons of radioactive sodium remain in the piping and other equipment of the trouble-prone Monju prototype fast-breeder nuclear reactor, which may be ordered decommissioned, it was learned Sunday.

It has not been decided how to dispose of the radioactive sodium, said sources at the Japan Atomic Energy Agency, the operator of Monju. If the government decides to scrap the reactor, sodium disposal is expected to be a difficult challenge.

Sodium is used as a coolant at Monju, while water is used at conventional nuclear reactors. Sodium is a tricky chemical element that burns intensely if it comes into contact with air or water.

According to the agency, the Monju reactor has some 1,670 tons of sodium. Radioactive substances are contained in 760 tons of the total as it circulates inside the reactor vessel.

The Monju reactor needs to be drained of the sodium if it is to be demolished.

Radioactive and chemically active sodium has to be sealed in containers. There is no precedent of radioactive sodium disposal in Japan.

“We plan to consider the method of disposal if a decision is made to decommission (Monju),” an official said.

Monju, located in Tsuruga, Fukui Prefecture, is a core facility in Japan’s nuclear fuel cycle policy because, if running properly, the reactor produces more plutonium than it consumes.

More than ¥1 trillion, mostly from state budgets, has been invested in Monju. But the 280,000-kw reactor has operated for only 250 days since it reached criticality, or a self-sustained nuclear fission chain reaction, for the first time in April 1994, due to a raft of problems, including maintenance flaws, a sodium leak and fire and attempted coverup.

In November 2015, the Nuclear Regulation Authority advised the government to replace the operator of Monju. The government is carrying out a thorough review of the Monju project, including the possibility of decommissioning the reactor.

The disposal of the mixed-oxide, or MOX, fuel used at Monju is another significant issue. The amount of MOX fuel, a blend of uranium and plutonium recycled from spent nuclear fuel, that needs to be disposed of is estimated at 21 tons, but Japan is not equipped to carry out its disposal.

One option is to consign the disposal to a foreign country and receive the return of uranium and plutonium after the processing, along with radioactive waste.

But the agency’s cost estimate of ¥300 billion for decommissioning Monju does not include the expense of the overseas entrustment of MOX fuel disposal.

The agency aims to entrust France with the disposal of some 64 tons of MOX fuel that has been used at its Fugen advanced converter reactor, but no contract has been concluded. The Fugen reactor, also in Tsuruga, is slated to be decommissioned.

Spent MOX fuel contains larger amounts of highly toxic radioactive substances than spent uranium from conventional reactors.

The disposal of radioactive sodium and MOX fuel at Monju is emerging as an additional and difficult challenge for the government at a time when the final disposal site has not been decided for high-level radioactive waste from nuclear plants across Japan. ”

Jiji

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Accelerate water-purifying work at Fukushima plant to cut leakage risk — The Yomiuri Shimbun

” The volume of contaminated water continues to increase at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 nuclear power plant. Efforts to deal with this problem must be reinforced.

TEPCO has compiled a new set of measures to deal with the radioactive water. The steps are aimed at reducing to nearly zero the contaminated water inside reactor buildings, the prime source of the tainted water.

Under the new measures, the contaminated water accumulated in the basements of reactor buildings is to be purified and then transferred to storage tanks. At the same time, facilities exclusively used for purifying the tainted water are to be doubled, and the existing storage tanks will be replaced with larger ones, increasing the overall storage capacity.

Meanwhile, the volume of groundwater to be pumped up from the wells near the reactor buildings is to be increased. This is aimed at reducing the flow of underground water into the buildings, thus preventing a vicious cycle of generating more tainted water.

If all goes well, the increase in the volume of contaminated water is expected to nearly stop by 2020. We hope TEPCO will realize this goal steadily.

The measures taken so far have centered on the construction of “ice walls,” to prevent groundwater from entering the reactor buildings by freezing the underground soil around the buildings. Because this step has failed to prove effective even more than half a year after the related facilities were put into operation, TEPCO decided to shift its priority measures.

The new measures will require the approval of the Nuclear Regulation Authority. Both TEPCO and the NRA must cooperate closely so that the necessary work will not be delayed.

Consider ocean release

The reactor buildings have, in effect, turned into storage facilities for contaminated water. The volume of tainted water totals about 68,000 tons. Although the amount of radioactive material contained in the water has declined markedly when compared to the amount immediately after the nuclear accident occurred, it still remains at a high level.

The large amount of contaminated water inside the reactor buildings carries a risk of radiation exposure, posing a serious impediment to the work to decommission the plant. If highly radioactive water starts leaking underground out of the buildings and into the sea, it will create a serious situation.

Even if new measures proceed smoothly, however, tasks remain. The volume of purified water to be stored in the tanks is expected to nearly double by 2020 to about 1.2 million tons. Not only will this entail a huge maintenance cost, but there is also a danger that the water will leak if the tanks are damaged by an earthquake or other factors.

Releasing purified water that has met the existing safety criteria into the sea must be seriously considered. The discharge of purified water into the ocean has been routinely conducted at nuclear power-related facilities both at home and abroad.

It is important for both the government and TEPCO to do their utmost to explain such a plan in detail in order to win the understanding of local residents concerned. Efforts should also be made to take measures to prevent groundless rumors from adversely affecting the fisheries industry and other sectors.

It is also necessary to continuously ascertain the effect of the ice walls. Although nearly 100 percent of the walls have already been frozen, groundwater is reportedly flowing through thin gaps in the walls. Rainwater seeping through the topsoil has also increased the amount of groundwater inside the buildings.

TEPCO is proceeding with work to fill the gaps in the ice walls. If the work proves effective, the goal of reducing to zero the increase in the contaminated water will be realized two years earlier than envisaged. We hope TEPCO will strenuously work to block the flow of groundwater into the buildings. ”

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