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Seismic intensity of 5 on the Iwaki City, Fukushima Prefecture, Japan; operation suspended between Takahagi and Tomioka on Joban Line

May 22, 2022

At around 0:24 p.m. on March 22, an earthquake centered off the coast of Ibaraki Prefecture hit Iwaki City, Fukushima Prefecture, with an intensity of just under 5 on the Japanese seismic scale, while Koriyama City, Hirono Town, Tomioka Town, Namie Town, and other areas in Fukushima Prefecture registered an intensity of 4 on the Japanese scale. According to the Japan Meteorological Agency, the epicenter was about 5 km deep, and the magnitude of the quake was estimated at 6.0. There is no concern of a tsunami from this quake.

 According to East Japan Railway Company, the earthquake caused a temporary power outage on the Tohoku Shinkansen Line between Shin-Shirakawa and Shiroishi Zao, suspending operations, which resumed at 0:32 pm. The line was reportedly delayed by up to 10 minutes.

 Also, due to the earthquake, operation is suspended on the Joban Line between Takahagi (Takahagi City, Ibaraki Prefecture) and Tomioka (Tomioka Town, Fukushima Prefecture) on the up and down lines.
https://www.asahi.com/articles/ASQ5Q44YWQ5QUTIL00F.html?fbclid=IwAR23WM3gBJHdz7AUbi7pmI1lkOKNgpPyNpvK_TRmjrqeTGOk52FCnPCen8w

May 22, 2022 Posted by | Fuk 2022 | , , | Leave a comment

Fukushima Daiichi Nuclear Power Plant contaminated water, after all… “Protect our oceans!

May 21, 2022

Environmental Groups Perform Against Ocean Discharge of “Contaminated Water from Fukushima Daiichi Nuclear Power Plant 
Japan’s Nuclear Regulatory Commission Virtually Approves Ocean Discharge of Contaminated Water

Members of an environmental citizens’ group perform in front of the Japanese Embassy in Jongno-gu, Seoul, on the morning of March 20 in opposition to the ocean discharge of radioactive water from the Fukushima Daiichi Nuclear Power Plant.

 
Members of environmental citizen groups, including the Korean Citizens’ Center for Environmental Health and the Sea Committee of the Environmental Movement Coalition, held an emergency press conference in front of the Japanese Embassy in Jongno-gu, Seoul, on the morning of March 20, and made their opposition to the oceanic discharge of radioactive water from the Fukushima Daiichi nuclear power plant clear.

Members of environmental citizen groups shout slogans against the oceanic discharge of radioactive water from the Fukushima Daiichi Nuclear Power Plant in front of the Japanese Embassy in Jongno-gu, Seoul, on the morning of March 20.

Japan’s Nuclear Regulation Authority effectively approved Tokyo Electric Power Co.’s plan to mix radioactive water from the Fukushima Daiichi nuclear power plant with seawater and discharge it into the ocean starting next spring on March 18. TEPCO plans to treat the contaminated water with a multinuclide removal system (ALPS) and then dilute it with seawater to lower the tritium (triple hydrogen) concentration before discharging it into the sea. Once the approval process is complete, TEPCO plans to obtain the consent of the local authorities in charge and begin construction of facilities for the discharge in earnest. We collected photos of the site.

Japan’s Nuclear Regulation Authority effectively approved TEPCO’s plan to mix radioactive water from the Fukushima Daiichi Nuclear Power Plant with seawater and discharge it into the sea starting next spring on March 18.

Members of an environmental citizens’ group perform in front of the Japanese Embassy in Jongno-gu, Seoul, on the morning of March 20 in opposition to the discharge of radioactive water from the Fukushima Daiichi Nuclear Power Plant into the sea.

Jung Hyo Kim, Reporter (Inquiries: japan@hani.co.kr)
http://japan.hani.co.kr/arti/politics/43525.html?fbclid=IwAR23_nH_28-qvQTVP4UdvLlVro5H-m9EKbIJwhVYCoTWLH4cdRVAc_V9WyU

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

S. Korea denies report of alleged approval of Japan’s Fukushima water release plan

May 20, 2022

SEOUL, May 20 (Yonhap) — South Korea on Friday denied a Japanese media report claiming the Seoul government agreed to Tokyo’s plan to release radioactive water into the ocean from the crippled Fukushima nuclear power plant.

Earlier this week, a Japanese news agency reported that the new Yoon Suk-yeol government appears to be planning to have consultations with Japan on the premise that Tokyo will discharge contaminated water as planned, while the former Moon Jae-in government objected to the plan.

“Our government has never gone for Japan’s Fukushima water release plan. We are concerned about some arbitrary and subjective media reports,” Seoul’s foreign ministry said in a text message sent to reporters.

The ministry vowed utmost efforts to come up with “needed responses to have the contaminated water be disposed in a way that meets international laws and standards and in a safe manner from objective and scientific perspectives,” while continuing consultations with Japan.

In April 2021, Japan announced a plan to start discharging the radioactive water into the sea in 2023 in what is expected to be a decadeslong process, as all storage tanks at the Fukushima plant are expected to be full as early as fall of 2022.

Earlier this week, Japan’s Nuclear Regulation Authority gave initial approval for Tokyo Electric Power’s discharge plan, with final approval likely to come following a 30-day public comment period.

Protestors from civic groups stage a protest rally in front of the Japanese Embassy in Seoul on May 20, 2022, to voice their objection to Japan’s decision to discharge water into the sea containing radioactive materials stored at the Fukushima nuclear power plant. (Yonhap)

https://en.yna.co.kr/view/AEN20220520010800320?section=national/national

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Korea to keep close tabs on Japan’s Fukushima water discharge plan

Civic activists hold a rally in Seoul to oppose Japan’s planned release of radioactive water from the crippled Fukushima plant into the ocean, April 20. According to the foreign ministry, Korea will step up communication with Japan and the U.N. nuclear watchdog over Tokyo’s planned release of the radioactive water.

May 22, 2022

Korea will step up communication with Japan and the U.N. nuclear watchdog to address health and security concerns over Tokyo’s planned release of radioactive water from the crippled Fukushima nuclear power plant into the ocean, the foreign ministry said Thursday.

Japan’s Nuclear Regulation Authority gave initial approval Wednesday for Tokyo Electric Power’s plan to discharge water from the plant starting around early 2023. Final approval is planned following a 30-day public comment period.

The foreign ministry said it remains committed to its efforts to ensure Japan safely releases the contaminated water from the plant in line with “international laws and standards” based on “objective and scientific perspective.”

The International Atomic Energy Agency (IAEA) is tasked with conducting safety reviews on the planned water release.

“The government will continue to strengthen communication between Korea and Japan, as well as with the international community including the IAEA, by prioritizing public health and security in relation to the (Fukushima) contaminated water,” ministry spokesperson Choi Young-sam told a press briefing.

In April 2021, Japan announced a plan to start discharging the radioactive water in 2023 in what is expected to be a decades-long process, as all storage tanks at the Fukushima plant are expected to be full as early as the fall of this year. (Yonhap)

http://m.koreatimes.co.kr/pages/article.asp?newsIdx=329479

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Japan’s nuclear water disposal plan irresponsible

This picture taken on March 5, 2022 shows storage tanks for treated contaminated water at the Tokyo Electric Power Company (TEPCO) Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima prefecture

May 20, 2022

Japan’s Nuclear Regulatory Authority granted initial approval on Wednesday for the Tokyo Electric Power Company’s plan to pipe contaminated water from the Fukushima nuclear power station into the ocean.

The water was used to cool damaged reactors after tsunami waves crashed into the nuclear power plant at Fukushima, knocking out its backup electricity supply and triggering meltdowns in three of its reactors, following an earthquake in 2011.

The decision shows the Japanese government and the Japanese company stand together in diverting this problem toward humankind. And the Japanese people are among the first who will suffer because of this disastrous plan. Local reports show many Japanese residents have already expressed strong opposition to the plan.

Satoshi Nozaki, head of the Fukushima Federation of Fisheries Cooperatives Associations, said the plan will spell the death knell of the local fisheries industry. Already, importers from the world over have rejected agricultural and fishery products from Fukushima.

A Fukushima resident surnamed Uno expressed her anger against the decision saying this is something that will affect generations to come.

Japan’s immediate neighbors, residents of China and the Republic of Korea, will face no less harm from the radioactive discharge. Chinese and ROK fishermen might have to abandon fishing in the region.

On hearing that they would be served fish from Fukushima, athletes from the ROK had brought their own food with them to the 2020 Tokyo Olympics.

All seas being interconnected, neither North America nor Europe can escape the fate if Japan discharges the contaminated water into the ocean; a CCTV report had said the nuclear waste water from Fukushima would reach North America within 57 days.

The Tokyo Electric Power Company started manufacturing pipes for discharging the water in April and the discharge is scheduled to begin nearly next year. The world should stop Japan from carrying out this disastrous plan.

http://global.chinadaily.com.cn/a/202205/20/WS6286df99a310fd2b29e5dddb.html

May 22, 2022 Posted by | Fuk 2022 | , , , , | Leave a comment

Japan OKs plan to release Fukushima nuclear plant wastewater

Japan’s nuclear regulator has approved plans by the operator of the wrecked Fukushima nuclear plant to release its treated radioactive wastewater into the sea next year, saying the outlined methods are safe and risks to the environment minimal

By Mari Yamaguchi Associated Press

May 18, 2022

TOKYO — Japan’s nuclear regulator on Wednesday approved plans by the operator of the wrecked Fukushima nuclear plant to release its treated radioactive wastewater into the sea next year, saying the outlined methods are safe and risks to the environment minimal.

The plan was submitted by the Tokyo Electric Power Company Holdings in December based on the government’s decision last year to release the wastewater as a necessary step for the ongoing plant cleanup and decommission.

A massive earthquake and tsunami in 2011 destroyed the Fukushima plant’s cooling systems, causing the meltdown of three reactors and the release of large amounts of radiation. Water that has been used to cool the three damaged reactor cores, which remain highly radioactive, has since leaked but was collected and stored in tanks.

There is still concern in the community and neighboring countries about the potential health hazards of the release of the wastewater that includes tritium — a byproduct of nuclear power production and a possible carcinogen at high levels.

The government and TEPCO say more than 60 isotopes selected for treatment can be lowered to meet safety standards, except for tritium, but that it is safe if diluted. Scientists say impact of long term low-dose exposure to the environment and humans are unknown, and that tritium can have a bigger impact on humans when consumed in fish than in water.

Japan nuclear authority chairman Toyoshi Fuketa said that the plan is made conservatively so the radiation impact on the environment could be still below the legal limit in case of any thinkable risks.

Under the plan, TEPCO will transport water that has been treated to below releasable levels through a pipeline from the tanks to a coastal facility, where the water is diluted with seawater.

From there, the water will enter an undersea tunnel to be discharged at a point about 1 kilometer (0.6 mile) from the plant to ensure safety and minimize the impact on local fishing and the environment, according to TEPCO.

The plan will become official after a 30-day public review, a formality that is not expected to overturn the approval.

The green light came just as the International Atomic Energy Agency’s Director Mariano Grossi arrived in Japan for meetings with top officials to discuss the plan, which has received international attention.

Fuketa will meet with Grossi on Friday after the IAEA director’s visit to the Fukushima plant on Thursday and meetings with other Japanese officials.

The government and TEPCO plan to begin gradually releasing the treated water in spring 2023.

The contaminated water is being stored in about 1,000 tanks at the damaged plant, which officials say must be removed so that facilities can be built for its decommissioning. The tanks are expected to reach their capacity of 1.37 million tons next year — slower than an earlier estimate of later this year.

Japan has sought the IAEA’s assistance to ensure the water release meets international safety standards, and to reassure local fishing and other communities as well as neighboring countries that have sharply criticized the plan.

A team of experts from the IAEA visited the plant in February and March for meetings with Japanese government and TEPCO officials. The task force, in a report issued late April, said Japan is making “significant progress” on the plan and taking appropriate steps toward the planned discharge.

https://abcnews.go.com/Technology/wireStory/japan-oks-plan-release-fukushima-nuclear-plant-wastewater-84800836

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Regulatory Commission approves plan to discharge treated water containing tritium, etc., into the sea.

May 18, 2022

The Nuclear Regulation Authority (NRA) has approved a plan formulated by Tokyo Electric Power Company (TEPCO) to discharge into the sea water containing tritium and other radioactive materials that have accumulated at the Fukushima Daiichi Nuclear Power Plant in accordance with government policy.

At the Fukushima Daiichi Nuclear Power Plant, in addition to groundwater and rainwater flowing into the reactor buildings, contaminated water containing radioactive materials is generated as a result of cooling melted-down nuclear fuel, and after purification, the so-called “treated water” still contains tritium and other radioactive materials that are difficult to remove.
The government has decided that the ever-increasing amount of treated water cannot continue to be stored on the plant’s premises, so it will be diluted to a concentration below the standard and discharged into the sea around next spring.
The Nuclear Regulation Authority (NRA) has been reviewing the plan.
At its meeting on March 18, the Nuclear Regulation Authority took up a draft review document summarizing the discussions to date, including a method to check the concentration of tritium and other substances in the treated water before discharging it, and an assessment of the effects of exposure to the surrounding environment and people, as described in the plan.
As a result, the Regulatory Commission approved TEPCO’s plan, finding no problems with the content of the review.
After soliciting opinions from the public for about a month from the 19th, the plan is expected to be officially approved.
TEPCO has been working since last December on the entrance and exit of the undersea tunnel for the offshore discharge, and after obtaining the approval of Fukushima Prefecture and local authorities, will start full-scale construction of facilities to dilute the treated water with seawater and the tunnel itself, aiming to complete the work around mid-April next year. The construction is scheduled to be completed by mid-April of next year.
However, concerns about harmful rumors persist, especially among local residents and fishermen, and the issue is how the government and TEPCO will gain the understanding of all concerned parties.

Fishermen’s Cooperative “Firmly Opposed”]
Haruhiko Terasawa, head of the Miyagi Prefectural Fisheries Cooperative Association, commented on the Nuclear Regulation Commission’s approval of TEPCO’s plan to discharge treated water from the Fukushima Daiichi Nuclear Power Plant into the ocean, “Ascidians caught in Miyagi Prefecture still cannot be exported to some countries. We are firmly opposed to the discharge of treated water into the ocean, and we hope that the government will first create an environment in which we can fish with peace of mind.
He added, “After the earthquake and the nuclear power plant accident, it was hard for us to sell seafood from Miyagi Prefecture. I don’t want to feel that way again. From overseas, the seas of Miyagi Prefecture and Fukushima Prefecture are seen as the same region, so I want Miyagi Prefecture to provide the same level of support as Fukushima Prefecture, where the nuclear power plant is located,” he said, calling on the national government and TEPCO to provide explanations that are satisfactory to local fishermen and take concrete measures to prevent harmful rumors.

Governor Murai: “Take measures against reputational rumors.”
In response to the Nuclear Regulation Authority’s approval of a plan to discharge into the sea water containing tritium and other radioactive materials that have accumulated at the Fukushima Daiichi Nuclear Power Plant, Governor Murai stated, “The prefecture will continue to request that disposal methods other than discharging into the sea be considered, and will also seek more concrete measures to ensure that our past efforts and achievements toward reconstruction will not be undone. In addition, the prefectural government will ask the central government and TEPCO to take more concrete and effective measures against rumors to ensure that the efforts and achievements made so far toward reconstruction will not be undone.
https://www3.nhk.or.jp/tohoku-news/20220518/6000019337.html?fbclid=IwAR3Y2DpVdxBz2yQ-fNdJAy7xxM9SF_qkNYmGoB_SgZTsPmLyi5l–HDQY7Y

May 22, 2022 Posted by | Fuk 2022 | , , , , | Leave a comment

Entry ban to end for village in Fukushima, but few plan return

A radiation monitoring post in the “difficult-to-return zone” in Katsurao, Fukushima Prefecture, showed a reading of 1.162 microsieverts per hour on May 15, several times the figure for before the nuclear disaster.

May 17, 2022

Evacuation orders will be lifted in June for the first time in the residential zone considered the most heavily contaminated from 2011 nuclear disaster in Fukushima Prefecture.

Residents who fled from the Noyuki district of Katsurao village northwest of the Fukushima No. 1 nuclear plant will be allowed to restart living there on June 12.

The decision followed a meeting between central government officials handling the nuclear accident and Katsurao officials on May 16.

The official decision is expected to be announced at a meeting of the government’s nuclear emergency response headquarters led by Prime Minister Fumio Kishida.

Eighty-two people of 30 households who used to live in the district will be eligible to return. The district is about 20 kilometers from the stricken nuclear plant and part of the government-designated “difficult-to-return zone.”

Eight people of four families have expressed their intention to return, according to village officials.

More than 11 years have passed since the area was put off-limits by the government. And many evacuees and their families have started new lives elsewhere.

Yoshinobu Osawa, a 68-year-old man who lives in public housing with his wife in Miharu, a town about 30 km from the Noyuki district, indicated that they will not return to their original home.

His house in the district was dismantled three years ago, and he believes he is too old to rebuild his life from scratch.

“The passage of 11 years after the disaster weighs heavily,” he said.

Following the triple meltdown at the plant in March 2011, the government issued evacuation orders for areas where annual radiation doses were estimated to reach 20 millisieverts, including all of Katsurao.

The government also designated areas with readings of 50 millisieverts a year in the difficult-to-return zone.

Seven municipalities, with a combined pre-disaster population of 22,000, fell in this category, including most of Katsurao as well as Okuma and Futaba, which co-host the nuclear plant.

Barricades were erected to prevent people from entering the difficult-to-return zone.

In December 2011, the government prioritized decontamination efforts in districts outside the difficult-to-return zone. It also said restrictions on living in the zone would remain for many years because of the high radiation levels.

But in a reversal of the policy, the government in August 2016 announced that it would clean up parts of the zone for a future lifting of the entry ban. A government study showed that radiation levels had dropped naturally in some areas of the zone despite the absence of decontamination work.

In 2016, Katsurao villagers whose homes were located in areas with readings of less than 50 millisieverts a year were allowed to return.

However, less than 30 percent have returned, according to the village hall, which is hoping that 80 people will return within the next five years.

Hiroshi Shinoki, the village chief, acknowledged the challenge at a news conference on May 16.

“We have finally reached the starting line for reconstruction,” he said. “But numerous problems have arisen as time passed by.”

The lifting of the entry ban for specific reconstruction areas in Okuma and Futaba is expected between June and July.

Osawa noted that cleanup work has reduced the radiation levels of the Noyuki district to less than 20 millisieverts a year.

Still, the figure is 10 times that of the pre-disaster doses.

He said he cannot gather mushrooms and edible wild plants like he used to because they are now contaminated.

(This article was compiled from reports by Susumu Imaizumi, Tetsuya Kasai, Keitaro Fukuchi and Senior Staff Writer Noriyoshi Ohtsuki.)

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Chinese FM urges Japan to immediately stop construction of nuclear wastewater discharge project

Tanks at the crippled Fukushima nuclear power plant store nuclear-contaminated wastewater

May 17, 2022

China’s Foreign Ministry on Tuesday urged the Japanese government to immediately terminate the construction of the nuclear-contaminated wastewater discharge project near the Fukushima nuclear power plant by Japan’s Tokyo Electric Power Company (TEPCO), stressing that countries across the Pacific have expressed serious concern and firm opposition to Japan’s wastewater-dumping decision.

Chinese Foreign Ministry Spokesperson Wang Wenbin noted at Tuesday’s press conference that it is irresponsible for Tokyo Electric Power Company to push ahead with the project of dumping nuclear-contaminated wastewater into the sea in disregard of the serious concerns of local residents and the international community.

Japan’s Nuclear Safety Commission (NSC) announced on Monday that it will discuss a draft review of the Tokyo Electric Power Company’s plan to discharge nuclear-contaminated wastewater from the Fukushima nuclear plant into the sea at its regular meeting on May 18. If agreed, the plan could be approved after a process including soliciting public opinions.

The Japanese government has so far failed to provide a convincing explanation on the legitimacy of the discharge program, on data reliability of the contaminated water, on the effectiveness of purification devices, and on the uncertainty of environmental impact, Wang said.

Given the potential harm of the wastewater to the marine ecological environment, food safety and human health, opposition voices from the Pacific Rim countries and the Japanese public have never stopped since the decision was made one a year ago.

Countries including China, South Korea, Russia and some Pacific island nations have expressed concerns; multiple Japanese civil organizations launched a petition with the signatures of 180,000 Japanese people to resist the project, the spokesperson noted.

According to TEPCO, the total amount of the nuclear-contaminated water in Fukushima reached 1.293 million tons at the end of March and continued to increase, and the contaminated water would be diluted with seawater and discharged.

It is estimated that 254 liters of clean seawater are needed for each liter of nuclear-contaminated wastewater, so the total amount of contaminated water Japan will eventually release into the ocean will exceed 300 million tons.

Wang stated Japan should pay attention to the concerns of the international community and the Japanese people, revoke the wrong decision, stop all preparations for the discharge project, and fulfill its due international obligations.

https://www.globaltimes.cn/page/202205/1265871.shtml

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Japan to Lift Evacuation Order for Fukushima Katsurao Area June 12

May 16, 2022

Japan will lift on June 12 an evacuation order for a Fukushima Prefecture district that has been in place since the 2011 nuclear disaster.
The district in the northeastern village of Katsurao, designated as a specified reconstruction and revitalization base, will become the first area in the so-called difficult-to-return zone to host permanent residents again.
The central government’s nuclear disaster response headquarters, as well as the Katsurao village and Fukushima prefectural governments, announced an agreement on the removal of the order at a news conference in the village office.
In 2011, all Katsurao residents were ordered to evacuate due to the triple meltdown at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 nuclear plant in the prefecture.
Later, the evacuation order was lifted for most of the village. Still, the Noyuki district, which is some 1,600 hectares and accounts for some 20 pct of the village, remains designated the difficult-to-return zone due to high radiation levels.

https://sp.m.jiji.com/english/show/19741?fbclid=IwAR0N_CPpxeKUcnCPZ_ENFuS3SRPMxfsWUfVRDU6RY4IzDDmlmp0XoKZL9hk

May 22, 2022 Posted by | Fuk 2022 | , , | Leave a comment

Analysis of particles containing alpha-emitters in stagnant water at torus room of Fukushima Dai-ichi Nuclear Power Station’s Unit 2 reactor

May 16, 2022

Abstract

Particles containing alpha (α) nuclides were identified from sediment in stagnant water in the torus room of the Fukushima Dai-ichi Nuclear Power Station(FDiNPS)’s Unit 2 reactor. We analyzed uranium (U), which is the main component of nuclear fuel, using scanning electron microscopy (SEM). Other α-nuclides (plutonium [Pu], americium [Am], and curium [Cm]) were detected by alpha track detection and the morphology of particles with α-nuclides were analyzed by SEM-energy dispersive X-Ray (EDX) analysis. Several uranium-bearing particles ranging from sub-µm to several µm in size were identified by SEM observation. These particles contained zirconium (Zr) and other elements which constituted fuel cladding and structural materials. The 235U/238U isotope ratio in the solid fractions that included U particles was consistent with what was found for the nuclear fuel in the Unit 2 reactor. This indicated that the U of similar fuel composition had made finer. The α-nuclide-containing particles identified by alpha track analysis were several tens to several hundred µm in size. The EDX spectra showed that these particles mainly comprised iron (Fe). Since the amount of α-nuclide material was very small, Pu, Am, and Cm were adsorbed on the Fe particles. This study clarifies that the major morphologies of U and other α-nuclides in the sediment of stagnant water in the torus room of FDiNPS’s Unit 2 reactor differed.

Introduction

TEPCO’s Fukushima Dai-ichi Nuclear Power Station (FDiNPS) was severely damaged by the earthquake and resulting tsunami that struck on March 11, 20111. At the time, Units 1–3 of the six reactors were in operation, and the nuclear fuel in the Units 1–3 reactors was damaged. Seawater and freshwater were injected to remove the decay heat from the nuclear fuels. The water remained in the basement of the building, and the components of the nuclear fuel dissolved in it, resulting in highly radioactive stagnant water. The stagnant water contained radionuclides, such as fission products and actinides derived from nuclear fuels. A chemical treatment process was established to remove the radionuclides, and a recirculating engineering system was established to reuse the recovered cooling water. Since then, the amount of stagnant water has been gradually reduced, but it was discovered that the fine particles containing a higher concentration of Alpha (α)-emitting radionuclides were settling basement in the reactor building2. The concentrations of alpha-nuclides (102–105 Bq/L) in the stagnant water including sediments were higher than the cooling water in the downstream building. Alpha-emitting radionuclides such as uranium (U) and plutonium (Pu) can cause serious internal exposure upon entering the human body. Alpha-nuclides should be strictly controlled when compared to caesium(Cs)-137 and strontium(Sr)-90, which are the main nuclides in fission products. Technology must be developed to effectively remove the alpha-nuclides from the stagnant water. For this purpose, we collected stagnant water in the torus room in the basement of the reactor building of Unit 2 and conducted radiochemical analysis of the precipitates in the stagnant water.The stagnant water is a higher concentration compared with what was detected at the entrance to the Cs adsorption system. In addition, the presence of α-emitting radionuclides was confirmed in the samples containing mixed sludge components from the stagnant water in the reactor building. To proceed with the treatment of the stagnant water deep inside the reactor building in the future, a better understanding is required of the different types of α-emitters, particularly those included in particulate solids in the stagnant water.

In existing research, radioactive particles containing U were detected in association with Cs microparticles (CsMPs) outside the FDiNPS site and their physicochemical composition and morphology were analyzed3,4,5,6,7,8. Abe et al.3 collected CsMPs emitted from the FDiNPS from the atmosphere and analyzed them using synchrotron radiation X-rays to detect U in the CsMPs. Ochiai et al. detected U particles of several hundred nm in CsMPs by scanning electron microscopy-X-ray detection (SEM-EDX) analysis. Their results reflected the composition of UO2 on magnetite by observing the diffraction pattern obtained using transmission electron microscopy. Similarly, diffraction patterns of UO2 and zirconia were obtained from mixed particles of Zirconium (Zr) and U in CsMPs, respectively. This indicated that U was present in CsMPs in both UO2 nanocrystals and U-Zr nanocrystrals forms6. Kurihara et al.8 found that the U in the fuel composition of the Unit 2 reactor was present in the CsMPs by analyzing the isotope ratios of 235U and 238U in the CsMPs using nanoscale secondary ion mass spectrometry. The release of fuel-derived Pu into the environment has also been reported by soil analysis9,10,11,12,13, airborne particles14, and CsMPs7. For americium (Am) and curium (Cm), few reports have been published regarding their release into the environment11. Recently, Morishita et al.15 detected particles containing α-emitters in smear samples collected from inside the FDiNPS using an α-ray imaging detector. The maximum energy of the α-rays indicated the presence of 238Pu; γ-ray spectra indicated the presence of 241Am. The morphology of these α-emitters was not observed.

In this study, we analyzed the concentrations and forms of U and other α-emitters in liquid and solid phases to obtain the basic data necessary for considering a removal method for α-emitters in the stagnant water of Unit 2 of the FDiNPS. The search for radioactive particles in existing studies was conducted primarily using imaging plate (IP)4 or sodium iodide scintillation counters8,16 and by detecting γ-rays from CsMPs. However, while these methods are effective for CsMPs with high radioactivity, it is difficult to selectively detect α-emitters that are present in small amounts and with low specific radioactivity. Therefore, we decided to use a combination of an automated particle measurement method using SEM-EDX17 and a method for detecting particles containing α-emitters using solid-state track detectors18,19,20,21,22,23,24

Results and discussion

Particle size distribution of solids in the stagnant water containing uranium and alpha-emitters

Figure 1a shows a schematic of a sampling location of a stagnant water sample in this study. Figure 1b shows how the particles settled after the sample was collected. The reddish-brown particles had settled over time. The solids in the stagnant water were classified and the U concentration of each fraction was measured by inductively coupled plasma mass spectrometry. The results are shown in Table 1.

As indicated, 238U was quantified in all fractions of all particle sizes, indicating its existence in various particle sizes. More than 99 % of U was present in fractions larger than 10 μm. The 235U/238U isotopic ratio was approximately 1.9 %, which closely matched the Unit 2 composition (1.93 %)25. Analysis of the total α-activity in each fraction showed that more than 99.8 % of the α-emitters were present in fractions larger than 10 μm (see Supporting Information, Table S1). These results suggested that most of the U and α-emitters in the stagnant water sample of the Unit 2 were present in particle fractions larger than 10 μm. Accordingly, a search for particles containing U and α-emitters was attempted using particles in solid fractions.

Detection and composition analysis of uranium particles using scanning electron microscopy-X-ray detection

As the main U isotopes (235U and 238U) in the fuel composition have a long half-life and low specific activity, SEM-EDX was adopted to detect U-rich particles. Precipitates on the filter with a pore size of 5 μm were loaded onto carbon tape (Fig. 1c) and observed by SEM-EDX. Particles containing more than 3 % U by atomic ratio (hereafter referred to as “U particles”) were detected based on the results of elemental composition analysis. An example of the observation result of UP1 is shown in Fig. 2.

Black particle (UP1) was observed on top of the reddish-brown particles in the center of optical image in Fig. 2a. Figure 2b shows a backscattered electron detection(BED) image of the same region as Fig. 2a. In the BED image and its magnified view (Fig. 2b, c), the black particle in Fig. 2a had a high intensity. In general, a particle containing an element with a relatively higher atomic number yields a BED image with higher brightness. The particle (UP1) with high brightness in Fig. 2b, c should contain heavy element. The peaks at 3.18 keV (U Mα), 3.34 keV (U Mβ), and 3.55 keV (U Mγ)26 were observed within the EDX spectrum of the UP1 particle (Fig. 2d), indicating that the particle included U. According to the results of SEM-EDX composition analysis of the U particles (UP1 in Table S2), U was the main component. In addition, the distribution of components in the fuel-structure materials, such as Zr and Cr, was also observed on the U particle (Fig. 2e). In contrast, iron (Fe) was observed to have been distributed around the U particles, indicating that the U particles were attached to the Fe particles. These results suggested that the U particle would be particulate with fuel-structural materials.

Using the same procedure as in the above paragraph, 14 U particles were detected. The observed particle sizes and the elemental maps of U and Zr are shown in Fig. 3a. Elemental composition of U particles are shown in Table S2.

Uranium particles with size ranging from approximately 500 nm to 3 μm were observed. Uranium particles were attached to Fe particles or present on their own (Fig. S1). The content of Fe in the analyzed stagnant water sample was approximately 4,400 times higher compared with U, indicating that the main component of the filtered material was Fe. Uranium particles smaller than the filter pore diameter of 5 μm were trapped, suggesting that they were cake-filtered during centrifugal filtration.

The isotope ratios of U in this fraction were consistent with the fuel composition derived by ICP-MS measurements. The presence of U particles with an isotopic composition the same as the nuclear fuel suggested that these U in the stagnant water sample had been derived from reactor core. The release of U and Pu from the FDiNPS into the environment was investigated and clarified by analyzing bulk soil samples for Pu9,10,11,12,13 and measuring the isotopic composition of U3,6,9 and Pu particles7 associated with CsMPs. Fine U, U, and Zr particles, ranging in size from several tens of nm to several hundreds of nm, have been detected in association with CsMPs in the environment6. In the present study, it was found that particles approximately 10 times larger in size than the particles associated with CsMPs existed in the stagnant water sample. It was also clarified that some U particles were not associated with CsMPs but existed independently.

Many U particles included Zr, which would have been derived from cladding. The ratios of U and Zr in these particles are compared in Fig. 3b. The ratio of U to Zr in each particle varied. In addition, in some particles, Zr was not detected, suggesting that the particles retained their fuel form. An existing report6 suggested the existence of two types of U particles several hundred nm in size that had been derived from the FDiNPS and released into the environment; one of these particles was in the fuel form of UO2 and the other presented as a Zr mixed oxide.

Detection and analysis of particles containing alpha-emitters using alpha track detection

The distribution of α-emitters in solids was investigated using alpha track analysis. An example of α-emitter particles and observed alpha tracks is shown in Fig. 4a, b. The upper left part of the particle in Fig. 4a shows the presence of U particles UP10 and UP13 (Fig. 4c, d), which are identical to those shown in Fig. 3. The distribution of alpha tracks can be observed uniformly from the reddish-brown particles; the uneven distribution of the position of U particles is not presented. Only a few tens of alpha tracks were observed, even for the alpha tracks at the position of the UP1 particle (Fig. S2), which had the largest particle size among the detected U particles with a diameter of 3 μm (Fig. 3a). In comparison, several hundred alpha tracks can be observed in Fig. 4b. This result suggested that the main source of alpha tracks was not U particles but other α-emitters on the reddish-brown particles.

The particle with the most alpha tracks is shown in Fig. 5a, and the alpha tracks derived from this particle are shown in Fig. 5b. The SEM-EDX observation of this particle is shown in Fig. 5c. Three particles can be observed in this image, all of which were found to comprise mainly Fe, based on the elemental mapping results (Fig. 5d, e). Furthermore, the elemental analysis results showed that U and other α-emitters were not detected (Fig. 5d). An almost uniform distribution was observed of α-nuclides on the Fe particles; this indicated that the α-nuclides present in ionic form in the solution may have focused on the Fe particles.

Uranium was also detected in the fractions smaller than 10 μm; however, α-emitters were only detected in fractions larger than 10 μm (Table S1). As Fe particles were in much larger quantities and sizes than U, the most of Fe particles were present in fractions larger than 10 μm by cake-filtration. As a result, most of the α-emitters, such as Pu, Am, and Cm, were observed the fraction lager than 10 μm, although fine U particles were present in each fraction. Iron particles (Fig. 5) were approximately 100 μm in size, which were smaller than those in Fig. 4 (approximately 200 μm). The number of alpha tracks was much larger among the Fe particles in Fig. 5 than in Fig. 4. Thus, the amounts of α-nuclides were not proportional to the size of the Fe particles but varied between particles. As noted above, the contribution of U particles to the alpha tracks was minimal (Fig. S2), and the number of other α-emitters in U particles was negligible compared with the total amount of α-emitters.

Among the three particles, the IP1 particle, i.e., the main source of the alpha tracks, had been dissolved and α-ray measurements were performed. Figure 6 shows the α-ray spectra of the IP1. Alpha nuclides such as 239Pu, 240Pu, 241Am, and 244Cm were detected. For the particle analyzed in this study (IP1), the radioactivity ratio of 238Pu + 241Am to 239Pu + 240Pu was 4.03, and the ratio of 244Cm to 239Pu + 240Pu was 1.17, which was almost consistent with the fuel composition (4.50 and 1.14, respectively)25. Future work should clarify whether the variation of nuclides exists in each Fe particle.

Estimation of the chemical properties of uranium and alpha-emitter particles using micro-Raman spectroscopy

A Raman spectrum of the UP1 particle was obtained by micro-Raman spectroscopy. Figure 7a shows the Raman spectra obtained from the UP1 and uranium standard samples. The Raman peak of UP1 is located at approximately 730 cm−1, suggesting that it is in a different chemical state from UO2 and other U oxides. Figure 7b shows the Raman spectrum obtained from IP1. A Raman peak is only located at approximately 710 cm−1. Hanessh reported that natural ferrihydrite has only strong 710 cm−1 band27.The Raman spectrum of IP1 showed that the surface of the Fe particles existed as ferrihydrite. Since the pH of the stagnant water sample was almost neutral and the adsorption of Pu28,29 and Am29 on Fe oxides was previously reported, the ions or colloids of these α-emitters would be adsorbed onto the Fe particles. Accordingly, it is suggested that α-nuclides are distributed on Fe oxides.

Conclusion

To eliminate the presence of α-emitters in the stagnant water, the particles were collected according to their size. Uranium particles were detected by SEM-EDX. Other α-emitters (Pu, Am, and Cm) were detected using alpha track detection and measured via alpha spectrometry. The average isotopic composition of U in the stagnant water sample match well with the fuel composition of FDiNPS’s Unit 2. The U particles in this sample were up to 10 times larger in size than those observed in the environment. It was also shown that Pu, Am, and Cm α-emitters were adsorbed onto Fe particles. These results demonstrated that the major morphology of U and other α-emitters was different. By understanding these types of α-emitters, important information was obtained for considering the separation method of α-emitters in the treatment of the stagnant water in the Unit 2.

Methods

Sampling of stagnant water in the torus room of FDiNPS’s Unit 2

A 40-mL of stagnant water sample in torus room of FDiNPS’s Unit 2 was provided form TEPCO HD. The stagnant water containing sediment accumulated on the basement floor was collected with a water sampler at 30th June, 2020.

Classification of solids and the distribution of uranium and alpha nuclides in the stagnant water

A 2-mL sample of the stagnant water was collected with a stirring well and transferred to a centrifugal ultra-holder (UHP-13C; Advantec) equipped with a 10 µm pore-size membrane filter (PTFE, o.d.13 mm; Merck). This centrifugal ultra-holder was set in a centrifugal separator (CN-820; Az-one) and centrifuged at a rotation speed of 3000 rpm for 10 min to separate the residue from the filtrate. The filtrate was sequentially filtered through 1, 0.1, and 0.02 µm filters. To dissolve the α-emitters in the residue and filtrate, each sample was transferred to a quartz beaker. Nitric acid (HNO3) and hydrogen peroxide (H2O2) solutions were added to the residue and the filtrate on the filter to create a 2 M HNO3–2% H2O2 solution, which was heated and dissolved on a hotplate at 130 °C for 1 h. Since the 0.02 µm pore size of the Anopore membrane filter (0.02 µm pore size; Whatman) was dissolved by HNO3 and the impure U contained by the filter was eluted, determination of the residue in the 0.02-µm section was derived from the difference in U concentration in the filtrate of the 0.1 and 0.02 µm filters. The heated sample solution was passed through a UTEVA-Resin column (UT-C20-A; Eichrom) conditioned with 6 mL of 2 M HNO3; 15 mL of 2 M HNO3 was used to wash out impurities in the column, and 10 mL of 0.01 M HNO3 was passed through to elute U adsorbed in the column. The collected eluate was heated on a hotplate at 130 °C until just before it dried up and then re-dissolved in 5 mL of 0.32 M HNO3 to make the solution for the ICP-MS measurement. Quantitative analyses of 235U and 238U were performed by ICP-MS (7700x ICP-MS; Agilent) in the “no-gas” mode using the calibration curve method with a natural U solution. The same procedure was repeated two times (sample name: SW-1,-2).

Detection of particles containing alpha-emitters using a solid-state nuclear detector

A 1 mL sample of stagnant water was taken and particles were collected by centrifugal filtration using a filter with a pore size of 5 µm (Millipore). Some of the collected particles were transferred to a carbon tape attached to an aluminum sample table using micro spatulas. The sample was placed on top of a solid-state track detector (TNF-1; Hartzlas) and exposed to alpha-rays from the sample for 19 h. Following the exposure, the detector was etched with a 7 M sodium hydroxide solution at 70 °C for 3 h. After the etching process, the detector was ultrasonically cleaned three times using ultrapure water and dried with a clean wipe. The alpha tracks created on the solid-state track detector were observed using an optical microscope (VHX-5000; Keyence), and the location of the particles with high concentrations of α-emitters was identified. The identified α-rich particles were analyzed to observe their composition using SEM-EDX (JEOL, JCM-7000).

Each of the three particles in the spot where the largest number of alpha tracks were observed was transferred onto a 5 mm square silicon (Si) chip using a micromanipulator (QP-3RH; MicroSupport). The micromanipulator was attached to a sampling tool (MTW-1; MicroSupport) and set with micro tweezers (TW-2525; MicroSupport). Under observation using a ×100 to ×1000 objective lens (VH-Z1000R; Keyence) in a microscope, the microparticles were separated using the micro tweezers and placed on the Si chip. The Si chip loaded with the microparticles was transferred to a quartz beaker using ceramic tweezers (TA-CK-20; Toray). Then, 2 mL of 2M HNO3 + 2% H2O2 was added to the beaker and heated on a hotplate at 150 °C for 1 h to dissolve the microparticles, then it was heated on a hotplate at 180 °C for approximately 1 h. Next, The Si chip was cleaned while removing it from the quartz beaker using 5 mL of 0.5 M HNO3. The mixture of sample and the rinsing solution was re-dried on a hotplate at 180 °C for approximately 1 h and 30 min. Next, 2 mL of 0.5 M HNO3 was added and the sample was heated on a hotplate at 180 °C for approximately 30 min. When the sample solution was approximately 0.1 mL, it was removed from the hotplate. The sample preparation was performed by heating a sample holder for α-ray measurement (o.d.20 mm, stainless steel) at 100 °C, then dropping the sample solution to spread it in the center and baking it on the sample holder.

Detection and analysis of uranium-containing particles using scanning electron microscopy with energy dispersive X-ray analysis

The same sample that had been used to complete alpha track analysis was used for U-containing particles larger than 0.5 µm in diameter using the automatic particle finder17 of the SEM-EDX. First, the field of view was fixed by observing the back-scattered electron image of part of the sample for observation at a magnification of ×1500. Then, in the field of view, the lower limit of brightness was set so that heavy elements beyond Zr could be detected; heavy element particles were automatically detected. The detected particles were automatically elementally analyzed and identified as particles containing more than 3% U by atomic ratio, based on the results of elemental composition analysis. For each U particle detected by the automated particle finder, EDX mapping analysis was performed to determine the elemental composition of U particles. The U and Zr ratios were calculated from the intensity of the 3.18 keV (U Mα) and 2.04 keV (Zr Lα) lines, which were obtained from the EDX spectra of the U particles.

Microscopic Raman spectroscopic analysis of uranium particles and alpha-emitter particles

The micro-Raman spectrometer (Micro-RAM 532A; Lambda Vision Inc., Japan) used in this study was equipped with a 532-nm neodymium-doped yttrium aluminum garnet laser and a Raman charge-coupled device detector. The laser was focused onto the sample using a ×100 magnification objective lens. The laser power at the sample position was measured using an optical power meter (3664; Hioki Inc., Japan). In this study, the laser power at the sample position was adjusted to 0.4 mW for the measurement of U particles. The acquisition times measured 60 s. Each spectrum made of five accumulations was acquired for each particle. For the measurement of each standard U particle, the laser power at the sample position was adjusted to 0.03 mW. The acquisition times measured 60 s. Each spectrum made of ten accumulations was acquired for each uranium particles. For the measurement of α-emitter particles, the laser power at the sample position was adjusted to 0.1 mW. The acquisition times measured 10 s. Each spectrum made of five times was acquired.

Data availability

The data that support the findings of this study are available from Tokyo Electric Power Company Holdings Inc. but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of TEPCO HD.

To read more: https://www.nature.com/articles/s41598-022-11334-1

May 22, 2022 Posted by | Fuk 2022 | , , , , , | Leave a comment

Aversion to food from Fukushima remains high in South Korea

TEPCO’s preparing the public for the release of the accumulated stored radioactive water lying through their teeth as always, with the help of the JUapanese mainstream media:

‘The water will be diluted with seawater to bring its radiation level to well within safety standards’

Storage tanks for treated radioactive water line the Fukushima No. 1 nuclear power plant in April 2021.

May 16, 2022

Nearly 80 percent of South Koreans want to avoid food products from Fukushima Prefecture regardless of the water-release plan at the crippled Fukushima No. 1 nuclear power plant, a survey showed.

The Reconstruction Agency conducted the online survey in January and February in 10 countries and regions to gauge international feelings toward Tokyo Electric Power Co.’s plan to discharge treated radioactive water into the sea as early as spring 2023. A total of 2,700 individuals responded.

The survey results, released on April 26, will be used to take countermeasures against negative publicity from the water-release plan that could hurt the image of products from the prefecture, the agency said.

The government in April 2021 decided to discharge the water to reduce the more than 1 million tons of processed water stored at the plant.

Although the treatment process cannot remove tritium, the water will be ‘diluted with seawater to bring its radiation level to well within safety standards’, TEPCO has said.

According to the survey, 13 percent of respondents in Japan “do not want to buy” Fukushima-derived foodstuffs as of now. The ratio rose slightly to 14 percent when the water-release plan was included in the scenario.

The percentage increases were 5 to 8 points in five nations and regions, including Hong Kong, Singapore and the United States.

In South Korea, about 77 percent said they do not want to buy Fukushima-made products regardless of whether the water is discharged into the sea.

The survey asked respondents if they knew that Japan’s food safety levels are controlled under some of the strictest standards in the world.

Around 50 percent each in Japan, Singapore, Hong Kong and Taiwan were aware, while the rate topped 30 percent in Europe and the United States.

However, just 15 percent of South Koreans said they were aware of Japan’s safety levels. And 56 percent said they knew about the safety levels but doubted the claims by the Japanese government.

Kosaburo Nishime, the reconstruction minister, on April 26 asked government bodies to show the international community data from the International Atomic Energy Agency and other third parties concerning the water-release plan.

The central government plans to bolster its radiation monitoring of waters around the Fukushima plant after the water is discharged.

https://www.asahi.com/ajw/articles/14613721

May 22, 2022 Posted by | Fuk 2022 | , , , | Leave a comment

Evacuation order to be lifted for Fukushima district on June 12

Katsurao Mayor Hiroshi Shinoki (right) and Masahiro Ishii (center), state minister of economy, trade and industry, attend a news conference about the lifting of an evacuation order for a district in Katsurao, Fukushima Prefecture, at the village on Monday

May 16, 2022

Katsurao, Fukushima Pref. – An evacuation order for a Fukushima Prefecture district that has been in place since the 2011 nuclear disaster will be lifted on June 12.

The district in the village of Katsurao, designated as a specified reconstruction and revitalization base, will become the first area in the so-called difficult-to-return zone to host permanent residents again.

The central government’s nuclear disaster response task force, as well as the Katsurao village and Fukushima prefectural governments, announced an agreement on the removal of the order at a news conference in the village office.

In 2011, all Katsurao residents were ordered to evacuate due to the triple meltdown at Tokyo Electric Power Company Holdings’ Fukushima No. 1 nuclear plant in the prefecture.

Later, the evacuation order was lifted for most of the village. Still, the Noyuki district, which totals some 1,600 hectares and accounts for some 20% of the village, remains designated as a difficult-to-return zone due to high radiation levels.

“We’ve finally reached the starting line,” Katsurao Mayor Hiroshi Shinoki told the news conference, stressing his resolve to provide people from the village with “support for the reconstruction of their lives.”

Masahiro Ishii, state minister of economy, trade and industry, who heads the task force, said he is “aware of the voicing of concerns mainly about radiation levels.”

“We’ll work carefully, including for the establishment of a consultation system, while holding discussions with the village,” he added.

According to the Katsurao government, the village’s specified reconstruction and revitalization base, which is some 95 hectares, has 82 registered residents belonging to 30 households.

But only four members of two households have taken part in a program from the end of November last year that allows locals to stay inside the district to prepare for the expected full return.

“Eleven years have already passed since the disaster, and we cannot return as soon as the order is lifted,” Sayuri Osawa, 67, said.

Osawa, who lives in the Fukushima town of Miharu, was among those who attended a briefing held on Sunday for displaced Katsurao residents.

“If I could return, I would work on a farm and plant flowers,” she said with a smile.

Fukushima has six specified reconstruction and revitalization bases.

Of the municipalities hosting the bases, the towns of Futaba and Okuma are hoping to see the evacuation order lifted for their bases in June and between late June and early July, respectively.

https://www.japantimes.co.jp/news/2022/05/16/national/katsurao-district-evacuation-order-lifting/

May 22, 2022 Posted by | Fuk 2022 | , , | Leave a comment