First On-Site True Gamma-Ray Imaging-Spectroscopy of Contamination near Fukushima Plant
Abstract
We have developed an Electron Tracking Compton Camera (ETCC), which provides a well-defined Point Spread Function (PSF) by reconstructing a direction of each gamma as a point and realizes simultaneous measurement of brightness and spectrum of MeV gamma-rays for the first time. Here, we present the results of our on-site pilot gamma-imaging-spectroscopy with ETCC at three contaminated locations in the vicinity of the Fukushima Daiichi Nuclear Power Plants in Japan in 2014. The obtained distribution of brightness (or emissivity) with remote-sensing observations is unambiguously converted into the dose distribution. We confirm that the dose distribution is consistent with the one taken by conventional mapping measurements with a dosimeter physically placed at each grid point. Furthermore, its imaging spectroscopy, boosted by Compton-edge-free spectra, reveals complex radioactive features in a quantitative manner around each individual target point in the background-dominated environment. Notably, we successfully identify a “micro hot spot” of residual caesium contamination even in an already decontaminated area. These results show that the ETCC performs exactly as the geometrical optics predicts, demonstrates its versatility in the field radiation measurement, and reveals potentials for application in many fields, including the nuclear industry, medical field, and astronomy.
Introduction
Following the accident in Fukushima Daiichi Nuclear Power Plants on 11 March 2011, a huge amount of radionuclides was released to the atmosphere. As in 2016, 137Cs and 134Cs, which radiate gammas mainly from 600 keV to 800 keV, still remain in Fukushima, and many areas are still contaminated as a result1. Operations of decontamination are called for in a wide area in Fukushima and its surroundings to satisfy a legal limit for the maximum exposure of 0.23 μSv/h at any publicly-accessible open spaces2. An effective method to measure and monitor gamma-ray radiation is essential for efficient decontamination work, and as a result there has been a surge of demand for gamma-ray instruments with a wide field of view (FoV) which quantitatively visualize Cs contamination.
Many gamma cameras have been developed to make imaging observations to help decontamination, based on the Compton camera (CC)3,4,5,6,7, pin-hole (PHC)8, and coded-mask technologies. However, none of them has detected more than a limited number of hot spots, or has reported any quantitative radiation maps, let alone imaging spectroscopy. The CC is the most advanced among these three, yet has an intrinsic difficulty in imaging spectroscopy, which is related to its Point Spread Function (PSF)9,10.
So far, the most successful evaluations for the environmental radiation in contamination areas have been made by backpacks11 and unmanned helicopters12,13. Although these methods are, unlike gamma cameras, non-imaging measurements, in which measurements at each point are made with either a spectrometer or conventional dosimeter, quantitative and reliable 2-dimensional distributions of radiation have been successfully obtained after several measurements with overlapping fields of view are combined. The downside is that they require a considerable amount of time and efforts, and thus are not practical to be employed in a wide area.
Another fundamental problem with all these methods is that they do not directly measure the radioactivity on the ground, but measure the dose at 1 metre high from the ground (hereafter referred to as “1-m dose”) instead, and hence require complex analyses to convert the measured dose to the actual radioactivity on the ground. Indeed, we show that the 1-m dose does not always agree well with that measured immediately above the ground, which suggests an intrinsic difficulty in obtaining an accurate radioactivity distribution on the ground from the 1-m dose.
After a few pilot experiments of decontamination were conducted in Fukushima, it turned out that the amount of reduction of the ambient dose by decontamination was limited. The reduction ratios, defined by the dose ratio compared between before and after decontamination, were approximately 20% only in lower ambient-dose areas (<3 μSv/h)2, while >39% in higher ambient-dose areas (>3 μSv/h). When a (high) dose is measured at a point, gammas that contribute to the dose can originate anywhere a few radiation lengths away (~100 m) from the point. The goal of decontamination is to somehow identify and remove those radiation sources. However, none of the existing instruments can identify them, i.e., none of them can tell where or even in which direction the radiation source is located. To untangle the sources of a dose of contamination, the directions of all the gammas, as well as their energies if possible, must be determined. It means that the brightness distribution around the point must be obtained.
To address these issues of existing methods and visualize the Cs contamination, we have developed and employed an Electron-Tracking Compton Camera (ETCC). ETCCs were originally developed to observe nuclear gammas from celestial objects in MeV astronomy14, but have been applied in wider fields, including medical imaging15 and environmental monitoring16,17. An ETCC outputs two angles of an incident gamma by measuring the direction of a recoil electron and hence provides the brightness distribution of gammas with a resolution of the PSF9,10. The PSF is determined from the angular resolutions of angular resolution measure (ARM) and scatter plane deviation (SPD)9,18. The ARM and SPD correspond to a resolution of the polar and azimuthal angles of an incident gamma, respectively. Since a leakage of gammas from their adjacent region to the measured point is correctly estimated with the PSF, quantitative evaluation of the emissivity anywhere in the FoV is attained.
The most remarkable feature of the ETCC is to resolve the Compton process completely; the ETCC does not only provide the direction of a gamma, but also enables us to distinguish correctly reconstructed gammas from those mis-reconstructed9. Thus, the ETCC makes true images of gammas based on proper geometrical optics (PGO), as well as energy spectra9 free of Compton edges10. The PGO enables us to measure precise brightness (or emissivity) at any points in an image using an equi-solid-angle projection, such as Lambert projection, without the information of the distance to the source, as shown in Fig. 1. The obtained emissivity can be unambiguously converted into the dose on the ground (hereafter the E-dose), of which the procedure is identical with that described in the IAEA report19, but without need of the fitting parameters. We find the E-dose to be consistent with the dose independently measured by a dosimeter, and thus confirm that remote-sensing imaging-spectroscopy with the ETCC perfectly reproduces the spatial distribution of radioactivity10.
Results
We performed the field test of gamma measurement in October, 2014 in relatively high-dose locations with the averaged ambient dose ranging from 1 to 5 μSv/h in Fukushima prefecture, using the compact 10 cm × 10 cm × 16 cm ETCC with a FoV of ~100°ϕ17. The SPD and ARM of the ETCC were measured to be 120° and 6° (FWHM), respectively, for 662-keV 137Cs peaks, which correspond to the PSF (Θ~15°), i.e., the radius of the PSF of 15° for the region that encompasses a half of gammas emitted from a point source9. It uses GSO scintillators and has an energy resolution of 11% (FWHM) at 662 keV. We chose the three different kinds of locations for measurements: (A) decontaminated pavement surrounded with not-decontaminated bush, (B) not-decontaminated ground, and (C) decontaminated parking lot. Figure 2a,c and d show their respective photographs.
We have found that the doses at 1-m and 1-cm measured with a dosimeter do not agree with each other, as demonstrated in Fig. 2a and b in the location (C). The 1-m dose, which is practically the emissivity averaged over the adjacent region of ~10 m, is the standard in the radiation measurement, presumably because it is useful to estimate potential health effects to the human body. The 1-cm dose, on the other hand, better reflects the emissivity on the ground at each grid point, of which the size is likely to be similar to the spatial resolution of the ETCC, and hence is useful to locate radioactivity on the ground for decontamination work. For these reasons, we adopt the 1-cm dose to compare with the emissivity measured with the ETCC in this work.
Figure 3a shows the photograph of FoV, overlaid with 1-cm dose at nine points and the E-dose map by ETCC, where the brightness (equivalent to the E-dose) is defined as the count rate of reconstructed gammas per unit solid angle (here 0.014 sr), corrected for the detection efficiency including the angular dependence of the ETCC9. Figure 3b shows the energy spectrum accumulated for the entire FoV, whereas Fig. 3c–e display those accumulated for the sky, the decontaminated pavement, and the not-decontaminated bush, respectively. The E-dose at the maximum brightness in Fig. 3a is estimated to be 2.6 μSv/h, which is consistent with the average of the 1-cm dose (0.9–4.3 μSv/h) around the centre of the FoV.
The spatial distribution of the E-dose is found to be consistent with that of the 1-cm dose, which was independently measured. The spectrum in Fig. 3e shows prominent peaks of direct gammas of Cs, which implies the contamination from the bush area, whereas the spectrum of the decontaminated pavement (Fig. 3d) shows much weaker Cs peaks, which implies the effect of the decontamination. The latter is dominated with low-energy scattered gammas, which emanate from inside of the ground and the adjacent areas. The spectrum of the sky (Fig. 3c) is clearly dominated with Compton-scattered gammas from Cs peaks (with the expected energy ranging from 200 to 500 keV) in the air. We should note that the spectra free of Compton scattering components enable us to make the unambiguous identification of the sources of radiation.
The results of imaging-spectroscopy in the two contrasting locations (B and C), in which no and thorough decontaminations, respectively, have been conducted, are shown in Figs 4 and 5. The exposure times are 80 min and 100 min, respectively. The ETCC gives spatially-resolved spectra, and accordingly the detailed condition of contamination at each point, similar to Fig. 3. In the contaminated location (B), although the energy spectrum of the FoV shows strong and direct gamma emission from Cs, Cs is found to be concentrated in the limited area of spot 1 (Fig. 4e), whereas little Cs is found in the other regions in the FoV (Fig. 4f). As such, imaging-spectroscopic measurement is a reliable method to unravel the state of contamination quantitatively. Even in the decontaminated location (C), both the image (Fig. 5a) and spectrum (Fig. 5f) reveal the existence of a “micro hot spot”, where some Cs remains on the ground and the spectrum has the dominant Cs peak (Fig. 5f), whereas the spectra for other regions (Fig. 5e) show that the main component is scattered low-energy gammas. Both the maps of 1-cm dose (Fig. 5a) and E-dose (Fig. 5b) show a hint of a small enhancement originating from a micro hot spot, although it is at a similar level to the fluctuation of the scattered gammas. The E-doses at the points of the maximum brightness in (B) and (C) are 5.0 and 1.3 μSv/h, respectively, which are also consistent with the 1-cm dose at the corresponding points.
Finally, we check consistency about a couple of properties of the ETCC and conventional dose measurements. First, we plot the total gamma counts obtained with the ETCC as 1-m doses at the position of the ETCC in Fig. 6a, and confirm a good correlation. Then, we plot the correlation between the 1-cm dose measured by the dosimeter and by the ETCC (E-dose) at the locations (B) and (C) in Fig. 6b. Except ~3 points adjacent to the hot spots in (B), the discrepancy between them is limited within ± ~30%. Considering the difference in the conditions, such as the size of the measured areas (~100 cm2 for a dosimeter and ~1 m2 for ETCC) and the energy range (>150 keV for a dosimeter and 486–1000 keV for ETCC), as well as the fact that a large dispersion in the accuracy of commercial dosimeters (±several 10%) has been reported, this amount of discrepancy is more or less expected. We conclude that good consistency between them is established for the wide range of the dose (0.1–5 μSv/h), and this is another proof that the ETCC achieves the PGO. In addition, the PGO gives the brightness of the sky over the hemisphere, and we find it to be comparable with that from the ground, after the difference in their solid angles is corrected (see the bottom row in Table 1). This means that roughly a half of the 1-m dose at any points originates from the sky. It then implies that the wide-band energy balance of gammas between the ground and the sky is in equilibrium and contribute to the ambient dose, presumably because the air is thick enough to scatter most of gammas emanating from the ground. It is consistent with the fact that the spectra of the sky (Figs 3c, 4c and 5c) are dominated with Compton scattering for Cs gammas (200–500 keV). This could not have been identified without spectra free of Compton edges. Our results also explain the reason why the amount of the reduction of the ambient dose was limited to often no more than 50% after decontamination work2 had been conducted in Fukushima, it is because a significant amount of radiation still comes from the sky in equilibrium.
Discussion
Firstly, let us convert the emissivity to the 1-cm dose, using only the brightness measured by the ETCC. Figure 1b schematically shows the dosimeter configuration for the measurement of 1-cm dose. Since the top and the upper sides of the dosimeter are shielded with tungsten 
rubber, it detects gammas emanating from the ground to the lower hemisphere only. The count density of the gammas which pass through the plane of the dosimeter (indicated as P in Fig. 1b) is estimated to be approximately 2πΣ · (1 − cos(θ = 80°)) = 5.2Σ, where Σ is emissivity on the ground. Then we convert the count density of gammas at the dosimeter position into doses in units of μSv/h with the conversion factor of 1 μSv/h = ~100 counts · sec−1 · cm−2 for 662-keV gammas in the dosimeter, based on the IAEA report19 (in page 85).
In the not-decontaminated location (B), 135 gammas were observed with the ETCC (dB) at the maximum brightness point in Fig. 4a, where the unit solid angle is 0.014 sr. The brightness of the gamma is calculated to be 135 counts · sec−1/(0.014 sr · 100 cm2) = 96 counts · sec−1 · sr−1 · cm−2, and then we get, from the relation Σ = dB, 5.2Σ = 500 counts · sec−1 · cm−2, which corresponds to the dose of 5.0 μSv/h (the two points indicated as 5.0 and 5.7 [μSv/h] in Fig. 4a). For the location (C), 35 gammas were observed at the maximum brightness point in Fig. 5a, and then dB (=Σ) = 35 counts · sec−1/(0.014 sr · 100 cm2) = 25 counts · sec−1 · sr−1 · cm−2 and 5.2Σ = 130 counts · sec−1 · cm−2, which corresponds to 1.3 μSv/h. The 1-cm dose at this point is found to be roughly equal to the average of 1.0–2.2 μSv/h in Fig. 5a. For the location (A), dB is calculated in the similar manner to be dB = 70 counts · sec−1/(0.014 sr · 100 cm2) = 50 counts · sec−1 · sr−1 · cm−2 and 5.2Σ = 260 counts · sec−1 · cm−2, which corresponds to the dose of 2.6 μSv/h. The 1-cm dose at this point is ~3 μSv/h, and is roughly equal to the average of 1–4.3 μSv/h in Fig. 3a.
For comparison, we also applied the simple method described in pages 96–101 in the IAEA report19, calculating the doses with a conversion coefficient of 8.7 × 10−3 (μSv/h)/(Bq/cm2) for θ~80° for the 1-cm dose, which is estimated by accumulating gamma-flux at each point from the ground with the tungsten rubber shield. This method is the one described in pages 96–101 in the IAEA report19. For the location (A), a gamma flux on the ground is calculated to be 2πΣ/0.85 = 369 (Bq/cm2) and then the dose is 369 × 8.7 × 10−3 = 3.1 μSv/h. For the locations (B) and (C), the doses are estimated to be 5.9 and 1.6 μSv/h, respectively. Thus, we confirmed that the results deduced by the two independent methods are consistent with each other.
Decontamination work in Fukushima faces serious difficulty; it is hard to pin down which region is badly contaminated from which radiation source without investing massive resources like wide-scale backpack measurements. The capability of the ETCC to measure the emissivity (or dose) independently of the distance would enable us to propose a novel approach to it. If a mapping of the brightness of 137Cs on the ground was carried out over the wide area with the ETCC by aircraft with the similar way conducted in 20122, we could visualize variation of the doses across the area, and could tell where decontamination work would be required most and how much.
As a different application, if multiple ETCCs are installed at various places in a nuclear plant to carry out a continuous three-dimensional brightness monitoring, we could not only detect, for example, a sudden radiation release by accident, but also make a quantitative assessment of where and how the release has happened. This would provide vital initial parameters to computer simulations to estimate the later dissemination of radioactivity over a wide area after an accident. In fact, simulations for this purpose faced a great difficulty in the past due to lack of reliable observed parameters of radio activity, because radiation monitoring was performed solely by repeated simple dose measurements. These simple dose measurements are unable to provide sufficient information over the wide area where the gamma radiation comes from, unless a huge amount of resources of manpower and hence budget are invested. Given that governments in many countries are confronted with the reactor dismantling issue, detailed and quantitative mapping of the radiation emissivity on the surfaces of reactor facilities, which would be well achievable with the ETCC, would be beneficial. The ETCC has immense potentials for immediate applications to various radiation-related issues in the environment.
Prospects
Some scientists assert that the detection efficiency of gas-based gamma detectors would be too low. However, we have found that some types of gas have sufficient Compton-scattering probability with the relevant effective areas of 110 cm2 and 65 cm2 at 1-MeV gammas with a 50-cm-cubic ETCC using CF4 gas and Ar gas at 3 atm, respectively9. Our prototype 30 cm-cubic ETCC with the effective area of a few cm2 at 300 keV was proved to perform expectedly well in MeV gamma-ray astronomy.
Now, we are constructing two types of more advanced ETCCs: one is a compact ETCC with the similar size and weight to the current model, but having a 20 times larger effective area (0.2 cm2 at 662 keV; type-A) and the other is a large ETCC aimed to be completed in 2018, which has a 1000 times larger effective area (10 cm2 at 662 keV; type-B). The details of Type-B are described elsewhere10.
Type-A has the similar size to the current ETCC, but has an increased TPC volume from 10 cm × 10 cm × 16 cm (rectangular solid) to 20 cm ϕ (in diameter)× 20 cm (cylinder), installed in the similar-sized gas vessel. It has a 5 times larger gas volume and 2.5 times wider detectable electron energy band with the TPC than the current model. In addition, if the mixed gas with Ar and CF4 (50%: 50%) at 2 atm is used, as opposed to the current Ar gas (~90% and some cooling gases) at 1.5 atm, the detection efficiency will be improved by a factor of 29. Then, the resultant detection efficiency (or effective area) will become 20 times larger than that of the current model, while keeping the similarly compact size and weight. The development of Type-A will be completed in 2017.
Type-B will provide the same detection limit for 6 sec exposure. If we perform a survey with Type-B from some aircraft at the altitude of 100 m, we will be able to make a spectroscopic map of a 1 km2 area with a 10 m × 10 m resolution for 1200 sec exposure to achieve the same detection limit, taking account of the absorption of the air. An unmanned airship is a good candidate for the aircraft, it flies slowly for an extended period and hence would enable us to do the precise imaging-spectroscopic survey. Then, the whole contamination area in Fukushima prefecture (roughly 20 km × 50 km) can be mapped with the same resolution as mentioned above in a realistic timescale of ~2 months, assuming 8 hours of work per day. Some of the spectra obtained in our aircraft-based survey might be found out to be generated by the gammas scattered by something, such as trees in woods, within the grid. Our survey will efficiently detect a hint for those areas, which can be then studied in more detail with on-site measurements, such as ones by backpacks11. No successful large-scale survey has been yet performed to monitor the radioactivity in Fukushima. Our upgraded ETCC will be capable of revolutionizing the decontamination work and more. We summarized the specifications of the current ETCC, type-A and type-B in Table 2.
Methods
Instruments and Measurements
The ETCC was mounted at 1.3 m high from the ground at its centre, tilted 20° downwards beneath the horizontal plane. The average distance to the ground in the FoV is ~4 m, which corresponds to the spatial resolution of ~1 m at the ground for its PSF. As a reference, we also made a mapping measurement of the dose at two heights of 1 m and 1 cm with every 1-m square grid in the FoV (except for the location (A), where the points of the measurements were sparser and irregular) with the commercial dosimeter (HORIBA, Radi PA-1100, http://www.horiba.com). In the dose measurement at the latter height (~1 cm), the top and four sides of the dosimeter were covered by tungsten rubber to shield it from the downward radiation (Fig. 1b).
We have developed a compact ETCC with a 10 cm × 10 cm × 16 cm gas volume, based on the 30-cm-cubic SMILE-II for MeV astronomy9. The ETCC is, like CCs, equipped with a forward detector as a scatterer of nuclear gammas and a backward detector as a calorimeter for measuring the energy and hit position of scattered gammas. The forward detector of the ETCC is a gaseous Time Projection Chamber (TPC) based on micro-pattern gas detectors (MPGD), which tracks recoil electrons. The TPC of the ETCC is a closed gas chamber, and thus can be used continuously for about three weeks without refilling with the gas5. The backward detector is pixel scintillator arrays (PSAs) with heavy crystal (at present we use Gd2SiO5: Ce, GSO). It is noted that, at the time of writing in 2016 after the survey work presented in this paper, we have been developing the Ethernet-based data handling system to replace the existing VME-based system. The latest ETCC available for field measurements is much more compact, which is built in the 40 cm × 40 cm × 50 cm base frame with the weight of 40–50 kg, and operated with a single PC with 24 V portable battery.
The contamination area in Fukushima is the similar environment to the space in the background dominated condition, where the radiation spreads ubiquitously. It is understandable that gamma cameras with the Compton method became the first choice to be employed for the decontamination work in Fukushima, following the precedents in MeV astronomy, even though it is clearly not the ideal instrument especially in the background-dominated environment.
Analytical method for deriving an emissivity from the measured distribution of gammas
Here, we explain how we measure the emissivity (or brightness) based on the proper geometrical optics (PGO) by the ETCC and how we estimate the dose on the ground from the emissivity measured by the ETCC. The following are the reason why no gamma camera but the ETCC can take a quantitative nuclear gamma image with the similar principle to that of optical cameras. According to the well-known formulas in PGO, the relation between emissivity Σ on the ground and detected brightness of the gamma in ETCC (dB) for solid angle Ω is given as Σ · A1 · dΩ1 = dB · A2 · dΩ2. and the relations dΩ1 = A2/D2, dΩ2 = A1/D2 hold, where A1 and A2 are the observed areas on the ground and the detection area in the ETCC (A2 = 100 cm2), respectively, and D is a distance between the ground and the ETCC. Figure 1a gives a schematic demonstration of it. These relations are then reduced to Σ = dB, which means that the emissivity is equal to the obtained brightness and is independent of the distance D in this optics. In practice, dB is calculated simply from the number of the detected gammas per unit solid angle corrected for the detection efficiency9. We should note that when the distance between a source and the ETCC (L) is comparable with, or longer than, the radiation length in the air (~70 m), dB in a unit solid angle must be corrected for the expected absorption, using the absorption coefficient (α) in the air for gammas with the relation dBcorrect = dB/(1 − exp(−L/α)).
Estimation of the emissivity and the detection limits
We estimate the detection limit using the sensitivity from the calibration data with a point source (137Cs, 3 MBq) in the laboratory17. We detected 662-keV gammas from the point source with a significance of 5σ at a distance of 1.5 m with the exposure time of 13 min. The point source increases the dose at the detector front by 0.015 μSv/h from a background dose. If the same amount of gammas entered the ETCC over the whole FoV, the significance would decrease by 
= 0.5σ, assuming that the background gamma increases proportionally from 1 to 100 to the number of pixels. The current ETCC comprises 100 pixels and one pixel is defined as an area of the unit solid angle in the FoV. In the case of a 100 min observation under the dose of 2 μSv/h at the detector front (assuming the case of Location (C), i.e., low dose), the total number of gammas increases by 
. The expected significance per pixel is then calculated to be 16σ/
= 1.6σ, which is consistent with the observed significances of (1.2–2.5σ) in the low-dose area (see the error bars in Fig. 6b). Similarly, the expected significance for the high-dose area is calculated and is found to be also consistent with the observed values of (3–5σ). Thus, our results of the on-site measurements are well consistent with the expected significances estimated from the calibration in the laboratory.
We also estimate the emissivity within the PSF and the detection limit to check consistency with the calibration data. As shown in Fig. 7 the covered area by the PSF for the distance L between a target and the ETCC is given by L · sinΘ. Since the number of gammas (brightness) within the PSF is conserved along the line of sight, the sensitivity in the PSF is independent of the distance L if absorption in the air is not taken into account. For example, for the distances L of 10 m and 100 m, the sizes of an area corresponding to a detector pixel are estimated to be 1 m and 10 m, respectively, when the same detection limits for both the distances are used. The detection limit for the ~2σ level of the ETCC is 0.5 μSv/h at a unit solid angle for an exposure of 100 min (see the distribution of red points in Fig. 6b). Note that the limit is proportional to 
, and hence can be easily scaled for different exposures and effective areas.
Additional Information
How to cite this article: Tomono, D. et al. First On-Site True Gamma-Ray Imaging-Spectroscopy of Contamination near Fukushima Plant. Sci. Rep. 7, 41972; doi: 10.1038/srep41972 (2017).
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Source: https://www.nature.com/articles/srep41972
Wildfires in Fukushima: reliable data or disinformation?
Government to release map of potential final nuclear disposal sites this summer
Solidified nuclear waste mixed with glass is placed in canisters at a reprocessing plant in Rokkasho, Aomori Prefecture, in 2012
The government has set the criteria for a map meant to identify potential final disposal sites for high-level radioactive nuclear waste, paving the way for its release as early as this summer.
The process of finding a host for nuclear waste could face challenges amid public concerns over safety.
Based on the map, the government will approach select municipalities to allow research to be conducted for suitable sites to store waste from nuclear power generation.
For permanent disposal, high-level nuclear waste needs to be stored at a final depository more than 300 meters underground for up to about 100,000 years until radiation levels fall and there is no longer potential harm to humans and the environment.
The government plans to create a permanent underground repository somewhere in stable bedrock so the canisters can be stored for tens of thousands of years.
The map is likely to classify which areas are geologically suitable for such a structure to be built deep enough underground. This would rule out areas near active faults and volcanoes as well as oil and coal fields.
Based on waste transport criteria, the map is likely to show that zones within 20 km of the coastline are favorable to host final disposal sites.
The government hopes other municipalities — not just the ones located near nuclear power plants — may also become interested in hosting the disposal facilities. It also wants to show that a variety of places nationwide are suitable for nuclear waste management.
The map was originally planned for a 2016 release but the publication date was later postponed, as some local governments were wary that disposal sites would be imposed on them.
About 18,000 tons of spent fuel currently exist in Japan. Including spent fuel that has already been reprocessed, the country’s total jumps to about 25,000 canisters of vitrified high-level waste, all of which needs to be managed.
The process to find local governments willing to host final storage started in 2002, but little progress was made due mainly to opposition from local residents.
In May 2015, the central government introduced a plan announcing that final depository site selection would be based on scientific grounds, rather than waiting for municipalities to volunteer.
Before presenting the map, the government will hold symposiums between mid-May and June at nine cities to explain the map criteria to the public. The cities include Tokyo, Nagoya and Fukuoka.
Radioactive waste is classified into two categories: The high-level type is generated from reprocessing spent fuel by separating the plutonium and uranium for recycling, while the low level type refers to all other waste.
High-level waste is a byproduct of fission in the reactor core, which is very hot and dangerous. It is mixed with glass and solidified before being placed in robust heat-resistant stainless steel canisters that are 130 cm high, 40 cm in diameter and weigh 500 kg each.
A full canister emits about 1,500 sieverts per hour — an extremely lethal biological level — and has a surface temperature in excess of 200 degrees.
Its radioactivity starts at 20,000 trillion becquerels. It will take about 1,000 years to fall to one-thousandth of that level, and tens of thousands of years to weaken to the same intensity as natural uranium ore, the Natural Resources and Energy Agency says.
Worldwide, only Finland and Sweden have been able to successfully decide on a final depository site for nuclear waste, while many other countries with nuclear plants face difficulties in doing so.
The United States decided in 2009 to call off a plan to build a site to dispose spent fuel in Nevada’s Yucca Mountain due to local opposition, but President Donald Trump earmarked funds to revive the plan in the budget proposal for fiscal 2018 unveiled in March.
In Japan, the selection process is also a touchy issue and has triggered conflicts in the communities around which prospective depository sites have been considered.
In one example, Minamiosumi Mayor Toshihiko Morita in Kagoshima Prefecture filed a criminal complaint against a 65-year-old resident for libel, claiming that his allegations that the rural town office had been actively inviting such a facility was not only groundless but also defamation.
The resident handed out flyers to about 500 households in the town in January which said Morita went to Tokai, Ibaraki Prefecture, and Horonobe in Hokkaido at the invitation of the private sector involved in the construction of nuclear waste disposal facilities. Both municipalities host nuclear-related facilities.
Morita flatly denied the allegations, telling Kyodo News in writing that he has heard “rumors” that there have been moves aimed at hosting a nuclear waste disposal facility but “I myself haven’t gone anywhere and been treated to anything.”
“I would reject any request from the central government” to host one, Morita said. The town approved an ordinance to reject a plan to host a nuclear waste disposal facility the year after the 2011 nuclear crisis at the Fukushima No. 1 plant.
A supporter of the mayor, however, did visit nuclear-related facilities in locations including Rokkasho, Aomori Prefecture, several years ago, according to the supporter’s admission, and a Tokyo company covered the expenses of the trip.
Mount Juman forest fire in Namie
A forest fire has been burning in the no-entry zone of Namie in Fukushima since April 29th, and is now in its fourth day. This has been the subject of many news reports of varying quality, and we are following the situation closely.
The site is among the most highly-contaminated by the Fukushima disaster, well within the “difficult-to-return” zone. Clicking this link will center the Safecast web map on the site of the fire at Juman-yama, which we derived by comparing terrain in news videos and in Google Earth.
To summarize what has been reported so far:
— The fire is in a mountainous area of Namie Town called Juman-yama, about 10 km from the Fukushima Daiichi plant. The Daiichi plant itself is not at risk from this blaze.
— The fire appears to have begun on Sat. April 29, caused by a lightning strike.
— Fire-fighters used helicopters to dump water on it, and it appeared to have largely died out on the morning of April 30, but high winds revived it shortly after.
— The burned and burning area has been growing, and as of May 2 was approximately 20 hectares.
— We don’t have much information about wind direction, which is variable, but predominant winds would blow the smoke eastward towards the ocean (generally over the Daiichi plant site and the towns of Okuma and Futaba).
— The most informative news report we’ve seen so far is from Fukushima Chuo TV, on May 1. Prof. Kenji Namba from Univ. of Tokyo notes that the fire can be expected to spread radioactive cesium from the trees in smoke and ash, a general risk pointed out by many experts in the past. He also notes that a monitoring post at Tomioka Station, about 15 km to the southeast of the fire site, has shown what appears to be a very small increase in radiation levels there since the start of the fire. We believe that data from many more points should be examined before ascribing any significance to this kind of reading.
Our closest Pointcast fixed sensor in the area is in Namie, about 7.8 km to the east-northeast of the fire. Its readings have remained relatively constant since the start of the fire, with no appreciable change in radiation levels detected. The time series graph for this sensor showing the change in radiation over the past 30 days can be accessed here.
We also have Pointcast sensors in the nearby towns of Tomioka and Odaka. Neither these nor any other Pointcast sensors show any appreciable increase in radiation levels so far.
Examining readings from government radiation monitoring posts shows what appear to be noticeable “bumps” at some locations around May 1. But these are not large spikes, and in general appear to be within the range of the variation seen in recent months. However, any detection at all would depend on the direction the wind is blowing the smoke plume.
Though any increases in radiation dose rates seen so far appear to be very small, inhaling the smoke from this fire could lead to an internal dose of radioactive cesium. We strongly suggest that people avoid inhaling this smoke. The area surrounding the fire where such risks would be highest are in fact closed to the public and therefore inaccessible, but the additional radiation risk to firefighters is making it difficult to send adequate personnel to battle the blaze.
News videos here:
Nippon Television, Tues. May 2, 2017
http://blog.safecast.org/2017/05/mount-juman-forest-fire-in-namie/
Wildfires in Namie
Wildfire is raging in the highly radio-contaminated area in Namie, Fukushima prefecture. Japanese authorities are minimizing the radiation risk. It is time to provide information from civil movement point of view. We are publishing here the translation of an article by Suzuki Hiroki, a freelance journalist.
What is happening in Namie, the 74th month after the Fukushima Daiichi accident?
There is a wildfire in the forest in the “difficult-to-return zone” causing rising concerns about the secondary dispersion of radioactive substances.
“Is it safe?” Voices of rage from the townspeople towards the central and local governments that hurried the evacuation order lifting.
A forest fire broke out on 29 April in Namie Town, Fukushima Prefecture, where one month had passed since the evacuation orders were lifted from a large part of the town. Moreover, it happened in the “difficult-to-return zone” where radio-contamination is especially high even in Namie town. Strong winds and high concentrations of contamination have made it difficult to fight against the fire and the fire has not been extinguished as of the night of May 1. Although the evacuation orders have been lifted as “the environment for everyday life is sufficiently in order”, it has been made clear that Namie has a perpetual risk of secondary dispersion of radioactive materials in the future. The fact that there is no means to prevent internal irradiation of firefighters as well as of returning residents brought home again the “reality” of the nuclear power plant accident.
[Firefighters cannot get close to the scene]
At the Sports Center near Japan Railway Joban Line Namie station fire-fighting helicopters in Fukushima and Miyagi prefecture land in the parking lot every few minutes. Water is put in the tanks with the hose connected to the fire hydrant. In the direction where the helicopter flew, smoke was still rising from the ridge of the mountain. Only the sound of the propeller echoes in the city empty of its population. Since April 29, the day when “Namie Town Security Watch Corps” rushed to the fire station, the feared forest fire is still ongoing 2 days later. The concern of secondary dispersion of radioactive materials is heightened.
The burned area has exceeded 10 hectares. Although the fire is weakening, the fire department is cautious in declaring the judgment of “repression” and “extinguishing” of fire, for the fire became strong once again after it was judged being “repressed”. On May 2, since 5:00 am, BABA Tamotsu, the mayor of Namie, and OWADA Hitoshi, head of the headquarters of the Futaba Regional Communities Area Union Fire Department, have been busy inspecting the area from the sky by helicopter.
“Jyumanyama” (altitude 448.4 meters), where lightning caused the fire, is located in the Ide district, which is designated as a “difficult-to-return zone”. Although the evacuation orders were partially lifted on March 31 from Namie, the “difficult-to-return zone” is still severely restricted from entering. The town’s fire brigade was called up, but its members cannot go close to the scene. It takes two hours on foot from the entrance of the mountain trail to the site, according to the headquarters of the Futaba Regional Communities Area Union Fire Department. The spot could not be specified easily. As soon as it was localized from the sky by the helicopter, firefighters climbed the steep slopes without trails while receiving the guidance of the Forestry agency and Iwaki Forest management office staff. In the meantime, smoke fueled by strong winds reduced visibility like a dense fog. But it’s not just smoke that is dangerous – there is the danger of radioactivity as well The effect of the absorption can attached to the protective mask only functions up to three hours. The exchange in the contaminated smoke is accompanied by the irradiation risk. Considering the health hazards of the members, it is not a good idea to enter the virgin forest without a discussed plan. On April 30 at noon, UCHIBORI Masao, the governor of Fukushima Prefecture requested to dispatch the 6th Division of the JGSDF (Yamagata Prefecture) for the disaster. The amount of water spray exceeds 400 tons by GSDF alone.
However, it is not possible to stop the secondary dispersion of the radioactive material even by the SDF. This is the specificity and danger of this forest fire.
(Top) At the Namie Regional Sports Center parking lot, fire-fighting helicopters came back one after another for water supply. The extinguishing activity from air is scheduled again on May 2 in the morning.
(Middle) From Jyumanyama mountains there was still smoke.
Secondary dispersion of radioactive materials is concerned. (Taken on May 1 around 11 a.m.)
(Bottom) Firefighters entered the field in protective gear and masks, but ” practically, there are no means to prevent the exposure to the radiation”.
“The radiation of the firefighters is unavoidable”.
“The secondary dispersion of radioactive materials is an alarming thing, but it has been expected. Judging that ‘the living environment is generally in order’, evacuation orders have been lifted, but once the wildfire starts, this is what happens. Did the government lift the evacuation orders after presenting these risks to the townspeople? I do not have any confidence in the central government nor in the local administration. They are good at appealing that everything is going well in this country. It was the same during the war. In that sense, it is a system of ‘self-responsibility’. I have no choice but to take care of myself”, said a man in his 40s, who was evacuated from the Hiwatari-Ushiwata administrative district. No active effort to announce the secondary dispersion of radioactive materials associated with forest fires was made by the town. It was delivered at last in the Mail magazine of the town at 10:00 a.m. on May 1. The following warning sentence was diffused: “Please do not approach carelessly, for it is dangerous”. It was not known to the townspeople for more than a full day because the fire report is dated Saturday evening. “The administration is difficult to move on Saturdays and Sundays,” said the General Affairs Disaster Security Division. On May 1 at 7:00 a.m., the same content was announced to the entire neighborhood by the disaster prevention radio, and “Notice of forest fire conditions” was published on the town homepage. However, there was no call for wearing a mask related to secondary dispersion of radioactive materials.
No emergency calls have reached the town council members. A certain council member said, “It is a good thing that I happened to learn about it by the television news. Otherwise, I wouldn’t have been able to answer when questioned by the townspeople about this. I want to request to make a contact system because the forest fire in the “difficult-to-return zone” is an emergency situation.”
This council member says, “it is only a personal opinion, but it is natural to assume that radioactive cesium will scatter with smoke and ash, and the fire extinguishing activity should be carried out while measuring how much radioactive material there is in the one square meter. However, it is not realistic, and I have to say that it is not possible to prevent internal irradiation exposure after all.” Another council member also said, “the risk was not examined when the evacuation order was lifted. The danger has been proven by the forest fire this time.” He is ready to take the matter to the Town Council.
As for the irradiation risk of the fire brigade, the headquarters of the Futaba Regional Communities Area Union Fire Department admit that while they can make a point “not to carry out the contaminated materials from the area”, there is no means to prevent the exposure of the fire brigade member. They can only try to shorten the time of stay in the “difficult-to-return zone”, but in reality it takes time to reach the site, and it is difficult to reach it. We have to admit that the exposure is unavoidable.” I wonder if we can consider the situation as “nuclear accident is under control”?
There was a warning about forest fires since even before the nuclear accident. The airborne radioactivity of Tsushima District, which is designated as “difficult-to-return zone” like Ide district, is still high. It is sad to say, but the risk of secondary dispersion of radioactive materials with a fire is high.
【Difficulty to monitor fine particles 】
There is no significant fluctuation in the airborne radioactivity measured by the monitoring posts installed inside and outside the town. The local media also actively convey the point. However, Mr. Yoichi Ozawa of the citizen’s group in Minamisoma City, “Fukuichi Environmental Radiation Monitoring Project”, pointed out that “radioactive particulates cannot be caught by a dosimeter or monitoring post.” In response to the forest fire, the above Project and the Citizen Radioactivity Monitoring Center “Chikurin-sha” (Hinode Town, Nishitama County, Tokyo) put several linen cloths in the town of Namie. It is thought that the secondary dispersion situation can be estimated by examining the adhesion of the fine particles that cause the internal irradiation.
The central government also faces a cautious posture about the secondary dispersion of the radioactive materials by combustion. On April 20, at the meeting with the residents of Iitate village the person in charge of the Cabinet Office asked the villagers “not to burn the field until the results of experimentation and analyses about how much radioactive materials scatter and adhere to crops etc. come out.” It is a reality that even the bureaucrats of the central government who rushed the evacuation order lifting are not able to affirm that it is safe.
According to the research by Mr. Ozawa and his colleagues, radioactive cesium of 17,000 Bq/kg was found in the fallen leaves near the Ogaki dam last autumn in the “difficult-to-return zone”. “The radioactive material is concentrated by several dozen times by burning. Some experts have pointed out hundreds of times”, says Ozawa. However, neither the central government nor Fukushima prefecture nor the Namie town warn about the internal irradiation at all.
“They lifted the evacuation order saying that it is safe and secure, but it’s not at all,” says a 70 year old resident angrily. A lot of worries about the exposure risk were voiced at the residents consultation meeting just before the lifting of evacuation orders. Some say, “it is useless to worry all the time. Since the nuclear power plant accident has happened, we have to think in a constructive way now”, but unfortunately many townspeople’s worries have become real. Moreover, it’s quite possible that the forest fire was caused by lightning. Namie will have to take the same risks in the future. The fire site continues smoldering. Radioactive materials are slowly spreading.
Published in Taminokoe shimbun, May 2, 2017.
https://fukushima311voices.wordpress.com/2017/05/02/wildfires-in-namie/
Sparking Fears of Airborne Radiation, Wildfire Burns in Fukushima ‘No-Go Zone’
Contaminated forests such as those outside fallout sites like Fukushima and Chernobyl ‘are ticking time bombs’
Kendra Ulrich, senior Global Energy campaigner for Greenpeace Japan on the Asakaze, a research vessel chartered by Greenpeace Japan, doing radiation survey work off shore of Fukushima Daiichi.
A wildfire broke out in the highly radioactive “no-go zone” near the crippled Fukushima nuclear power plant over the weekend, reviving concerns over potential airborne radiation.
Japanese newspaper The Mainichi reports that lightning was likely to blame for sparking the fire Saturday on Mount Juman in Namie, which lies in the Fukushima Prefecture and was one of the areas evacuated following the 2011 meltdown. The area continues to be barred to entry as it is designated a “difficult-to-return zone” due to continually high radiation levels.
Local officials were forced to call in the Japanese military, the Ground Self-Defense Force (GSDF), to help battle the blaze, which continued to burn on Monday. At least 10 hectares of forest have burned so far.
“A total of eight helicopters from Fukushima, Miyagi and Gunma prefectures as well as the SDF discharged water on the site to combat the fire,” The Mainichi reports. “As the fire continued to spread, however, helicopters from the GSDF, Fukushima Prefecture and other parties on May 1 resumed fire extinguishing operations from around 5 am [local time].”
An official with the Ministry of the Environment said Monday that there has been “no major changes to radiation levels” in the region, according to the newspaper, but added that they will “continue to closely watch changes in radiation doses in the surrounding areas.”
In a blog post last year, Anton Beneslavsky, a member of Greenpeace Russia’s firefighting group who has been deployed to fight blazes in nuclear Chernobyl, outlined the specific dangers of wildfires in contaminated areas.
“During a fire, radionuclides like caesium-137, strontium-90 and plutonium rise into the air and travel with the wind,” Beneslavsky wrote. “This is a health concern because when these unstable atoms are inhaled, people become internally exposed to radiation.”
Contaminated forests such as those outside fallout sites like Fukushima and Chernobyl “are ticking time bombs,” scientist and former regional government official Ludmila Komogortseva told Beneslavsky. “Woods and peat accumulate radiation,” she explained “and every moment, every grass burning, every dropped cigarette or camp fire can spark a new disaster.”
Wildfire continues in Fukushima
A wildfire has been raging for more than 2 days near the damaged Fukushima Daiichi nuclear power plant.
The fire started in a mountain forest on the outskirts of Namie Town in Fukushima Prefecture. The area is part of a zone designated as “no-entry” due to high radiation levels following the 2011 nuclear disaster.
Fukushima and Miyagi prefectures and the Self-Defense Forces are using helicopters to fight the blaze. They are also looking at the possibility of using ground crews.
Footage from an NHK helicopter on Monday morning showed smoke rising from wide areas and fires burning in several locations.
Local officials and firefighters say the blaze abated somewhat on Monday afternoon thanks to rainfall. The wildfire is estimated to have burned about 20 hectares of land so far.
Fukushima authorities ask troops to help deal with forest fires near crippled nuclear power plant
Fukushima prefecture has asked the Japanese Self-Defense Forces for help in handling forest fires that have swept areas near the crippled Fukushima power plant, local media report. Strong winds are hindering the firefighting efforts, however.
The forest fires broke out near the town of Namie, some seven kilometers from the disabled Fukushima Daiichi Nuclear Power Plant, on Saturday evening, Japanese NHK broadcaster reported.
Namie was evacuated following the 2011 tsunami and subsequent nuclear disaster in Fukushima.
The prefecture has deployed several helicopters to extinguish the fires, which are believed to have been caused by lightning. According to police, at least 10 hectares of forest have burned in the area.
There have been no reports of injuries or damage to buildings so far, Japanese media say.
With strong winds stoking the flames, the Fukushima Prefecture has requested help from the Self-Defense Forces, Japan’s de-facto army, on Sunday.
Earlier in April, residents of Namie, as well as those from the village of Iitate and the town of Kawamata’s Yamakiya neighborhood, totaling 22,100 people in all, were told they could return home – with the exception of those with houses in so-called no-go zones, where radiation levels are still too high, according to Japanese media.
So far, the homecoming has not been as successful as the government had hoped, as few residents have been eager to go back.
Results of a Fukushima Prefectural Government survey released on April 24 show that some 78.2 percent of the evacuated households have no intention of returning to their previous residences and plan to remain in the area they evacuated to.
https://www.rt.com/news/386662-fukushima-forest-fires-soldiers/
Wildfire rages in highly radioactive Fukushima mountain forest
This is bad news. Fires like this in contaminated forests aerosolize the radiation that covers the plants and has been taken up in the soil and redistributes it through the smoke. It makes no sense to bring people back to the territories in the vicinity of the highly radio-contaminated forests.
NAMIE, Fukushima — A fire broke out in a mountain forest near the crippled Fukushima No. 1 Nuclear Power Plant on the evening of April 29, consuming an area approximately 20 hectares in size, according to prefectural authorities.
The fire started on 448-meter-high Mount Juman in Namie, Fukushima Prefecture, prompting the prefectural government to request the dispatch of the Ground Self-Defense Force (GSDF) on a disaster relief mission on April 30. A total of eight helicopters from Fukushima, Miyagi and Gunma prefectures as well as the SDF discharged water on the site to combat the fire.
As the fire continued to spread, however, helicopters from the GSDF, Fukushima Prefecture and other parties on May 1 resumed fire extinguishing operations from around 5 a.m.
The area is designated as a “difficult-to-return zone” due to high radiation levels from the Fukushima nuclear disaster, and entry into the area is barred in principle.
According to the Fukushima Meteorological Office, a lightning advisory had been issued for the town of Namie when the fire broke out, and Fukushima Prefectural Police suspect that lightning was to blame for the blaze as they continue to investigate the cause of the incident.
As of May 1, there were no major changes to radiation levels in the heart of Namie and other areas near the fire scene, according to the Ministry of the Environment.
“We will continue to closely watch changes in radiation doses in the surrounding areas,” said a ministry official.
http://mainichi.jp/english/articles/20170501/p2a/00m/0na/003000c
Transfer sites for 610 tons of spent nuclear fuel undecided; decommissioning plans may be affected
Spent nuclear fuel is stored in a pool at the La Hague reprocessing facility in northwestern France in October. It is one of the most dangerous sites in the world, with its 10,000 tons of spent fuel. We were afraid of the Fukushima Daiichi fuel pool 4 but it was nothing: The whole fuel of the Hague corresponds to radiotoxicity 360 times greater than Chernobyl.
About 610 tons of spent nuclear fuel stored at seven of the 17 reactors in Japan that are set to be decommissioned have no fixed transfer destination, it was learned Sunday, threatening to hold up the decommissioning process.
If it remains undecided where to transfer the spent nuclear fuel, work to dismantle reactor buildings and other structures may not be carried out as planned.
The tally excludes the six reactors at Tokyo Electric Power Co. Holdings Inc.’s Fukushima No. 1 plant, which was heavily damaged by the March 2011 earthquake and tsunami.
The seven reactors are the Japan Atomic Energy Agency’s Fugen advanced converter reactor, the agency’s Monju prototype fast-breeder reactor, Japan Atomic Power Co.’s reactor 1 at its Tsuruga plant, reactors 1 and 2 of Kansai Electric Power Co.’s Mihama plant, reactor 1 of Chugoku Electric Power Co.’s Shimane plant and reactor 1 of Kyushu Electric Power Co.’s Genkai plant, according to the companies and the agency.
The Fugen reactor has 70 tons of spent mixed-oxide, or MOX, fuel, a blend of uranium and plutonium recycled from spent nuclear fuel.
The agency has abandoned its plans to move the MOX fuel out of the reactor site in the current fiscal year to March 2018. It has considered consigning the reprocessing of the fuel overseas but a contract has not been signed yet.
The agency’s schedule to finish the decommissioning work by fiscal 2033 has remained unchanged, but an official admitted that the timetable will be affected if a decision on where to transfer the spent fuel is not made.
As for the trouble-prone Monju reactor, the agency has yet to submit a decommissioning program to authorities. How to deal with 22 tons of spent MOX fuel at the reactor is a major issue.
The Mihama No. 1 reactor has 75.7 tons of spent conventional nuclear fuel and 1.3 tons of spent MOX fuel, while the No. 2 reactor has 202 tons of spent nuclear fuel. Kansai Electric plans to take them out of Fukui Prefecture, which hosts the power plant, by fiscal 2035, but the transfer location has not yet been selected.
At the Tsuruga plant’s reactor 1, Japan Atomic Power plans to transfer 31.1 tons of the reactor’s 50-ton spent nuclear fuel to the fuel pool of reactor 2, with the rest to be transported by fiscal 2026 to a Japan Nuclear Fuel reprocessing plant under construction in the village of Rokkasho in Aomori Prefecture.
After being postponed more than 20 times, the completion of the reprocessing plant is currently slated for the first half of fiscal 2018 and the blueprint is undergoing screenings by the Nuclear Regulation Authority, a nuclear watchdog.
As nuclear fuel cannot be brought into the reprocessing plant until it starts operations after receiving all necessary regulatory approval, it is uncertain whether the Tsuruga reactor fuel can be transferred as planned.
Chugoku Electric aims to transfer 122.7 tons of spent nuclear fuel at its Shimane plant’s reactor 1 to the Rokkasho reprocessing plant by fiscal 2029.
Kyushu Electric hopes to take 97.2 tons of spent nuclear fuel at the Genkai reactor 1 out of its fuel pool by fiscal 2029, but the destination has not been fixed.
At three other nuclear plants with reactors set to be decommissioned, spent nuclear fuel is mostly planned to be moved out of the current pools to other pools within the same plant.
In the case of Tepco’s disaster-stricken Fukushima No. 1 plant, the site of the 2011 triple meltdown accident, where the 2,130 tons of spent nuclear fuel will be transferred to has yet to be decided.
Still, the decommissioning work for the six reactors there will not be affected in any significant way for the time being, as more urgent tasks, such as a survey of melted fuel, have been given higher priority, officials said.
‘Yoshida’s Dilemma: One Man’s Struggle to Avert Nuclear Catastrophe’: But for him, Fukushima could have been much worse
Hero: Masao Yoshida disregarded orders to abandon the Fukushima No. 1 nuclear power plant. The actions of him and his team are credited with averting further disaster.
Disaster response, even at its most heroic, can fall to people who would rather be somewhere else.
So it was for Masao Yoshida, who, while helming the Fukushima No. 1 nuclear power plant during the disaster in 2011, gave the groan, “Why does this happen on my shift?”
But in some ways Yoshida, an industry veteran of 32 years, was the right man to handle the crisis. His leadership during those days on the edge, at times in defiance of orders from the top of the utility that employed him, is at the center of Rob Gilhooly’s new book “Yoshida’s Dilemma: One Man’s Struggle to Avert Nuclear Catastrophe.”
Gilhooly writes from the eye of the storm, putting the reader in the plant’s control room with almost claustrophobic immediacy. One of his challenges was to render the emergency in real-time. How much can prose, moving forward in measured steps, convey a lethal technology unraveling in extremis? How do you convey the breakdown of machinery without getting mired in technical detail?
“It was difficult,” says Gilhooly, who spent almost four years researching and writing the book. “What struck me about the plant workers — it sounded like complete chaos. My decision was not to make it sound orderly. I wanted it to appear chaotic, without the writing becoming chaotic itself. I tore my hair out over the technical details, because I wanted the book to be readable.”
In the end, the book is a cumulative experience — an intense ride that rewards endurance. Gilhooly weaves in the history of nuclear energy in Japan, interviews with experts and re-created conversations among the plant workers.
“Yoshida was a straight talker from Osaka — a larger-than-life personality,” says Gilhooly, who interviewed the superintendent off the record. “He was different from the other superintendents, more prepared to stick his neck out. He was sharper, more bloody-minded. When tipping his hat to authority, he may have done so with a quietly raised middle finger.”
This attitude might have saved lives, when, after a hydrogen blast at the No. 1 plant, Tepco HQ in Tokyo ordered staff to evacuate. Yoshida knew that the executives had little idea of what was actually happening at the plant. Going behind the backs of his superiors, he contacted then-Prime Minister Naoto Kan, insisting that leaving the plant would be reckless. The utility also ordered that seawater not be pumped through the reactor as coolant, since that would render it useless for energy generation in the future. Exposed to life-threatening levels of radiation, Yoshida and his team defied the order, scrambling to cool the overheating reactor with seawater.
The desperate move worked. The team managed to cool the reactor, and later the Fukushima Nuclear Accident Independent Investigation Commission, which was authorized by the Diet, concluded in its report that “(Yoshida’s) disregard for corporate instructions was possibly the only reason that the reactor cores didn’t explode.”
In Western media coverage of the Fukushima disaster, much was made of Japanese groupthink. A culturally ingrained obedience and a reluctance to question authority was blamed in part for the disaster. Still, the responses vary, and some staff put safety concerns over company loyalty.
“I didn’t want to editorialize,” says Gilhooly, who writes with a calm, thoughtful voice, avoiding the temptation of melodrama. “But yes, Yoshida — and others — refuted the stereotype that was used to explain parts of the disaster.”
Gilhooly is talking to a Japanese publisher, but thinks a translated version may prove difficult: His sources spoke freely about the events at the plant assuming the interviews wouldn’t be published in Japanese. Still, Gilhooly, who takes a stand in the book against using nuclear energy, hopes to fuel the ongoing debate in his adopted home.
“I just wanted to know the truth,” he says. “There is a discussion that needs to happen about nuclear power — about disaster un-preparedness in Japan. I wanted to contribute to that argument. It’s six years on and already we are airbrushing some things out.”
The book points out the gulf between rural Fukushima and the large cities consuming the energy it produced. Gilhooly talked to Atsufumi Yoshizawa, Yoshida’s deputy at the plant, who recalled the first home leave with his boss, a month after the disaster:
“Tokyo was … as though nothing had happened. They were selling things as usual, women were walking around with high heels and makeup as usual, while we didn’t even have our own clothes (which had been contaminated). I remember thinking, ‘What the hell is this? How can it be so different?’ I realized just how useless it would be to try and explain the situation at the plant to these people, what we had been through and the fear we had faced.”
It is a punch in the gut, then, to read about Yoshida’s death from esophageal cancer at age 58, just two years after his exposure to radiation. It’s one of the many elements of the Fukushima crisis that stirs anger, demanding a change that honors the lessons and sacrifice.
Gilhooly points out that, unlike Yoshida in the stricken plant, Japan has the chance to make positive choices about the future, choices that should be informed by the suffering in Fukushima.
“We should think more about how we use energy,” he concludes. “There are things we can do better, with small changes in lifestyle.”
14 microSv/h 5cm above from street-side soil Namie, Fukushima
From Birdhairjp
On 22 Apr 2017, I measured radiation in front of a temple of Onoda area,
Namie town of Fukushima prefecture Japan.
I monitored 0.94 micro Sievert per hour in air at chest hight
on road side near a utility pole.
And I monitored air dose rate 0.85 micro Sievert on asphalt road pavement.
There is a place, the monitor figures jump up.
There left highly contaminated soil at the street side.
2.3 micro Sievelt per hour, chest height.
13 to 14 micro Sievelt per hour 5 cm height from the soil.
18 to 20 micro Sievelt per hour when the monitor laid directly on the soil.
Soil contaminated with high concentration of radioactive material
It is like hell
Fukushima: Dispossession or Denuclearization?
Summary of the book:
The Fukushima nuclear power plant explosions and the Hiroshima and Nagasaki bombings are intimately connected events, bound together across time by a nuclear will to power that holds little regard for life itself. In Fukushima: Dispossession or Denuclearization? contributors document and explore diverse dispossession effects stemming from this nuclear will to power, including market distortions, radiation damage to personal property, wrecked livelihoods, and transgenerational mutations potentially eroding human health and happiness. Liberal democratic capitalism is itself disclosed as vulnerable to the corrupting influences of the nuclear will to power. Contributors contend that denuclearization stands as the only viable path forward capable of freeing humans from the catastrophic risks engineered into global nuclear networks. They conclude that the choice of dispossession or denuclearization through the pursuit of alternative technologies will determine human survival across the twenty-first century.
Contributing editors to Fukushima: Dispossession or Denuclearization? are Majia Nadesan, Antony Boys, Andrew McKillop and Richard Wilcox. Harvey Wasserman, Christopher Busby, Paul Langley, Adam Broinowski, Christian Lystbaek, and The Fukushima Five have also contributed chapters. Cover artwork by William Banzai7.
Proceeds from the book:
Proceeds from the book will be donated to the Fukushima Collective Evacuation Trial Team, a team of lawyers who are fighting in the courts in northern Japan to have children in Koriyama City, quite badly contaminated with radiation after the March 11, 2011 Fukushima Daiichi nuclear power plant disaster, evacuated to safe areas at government expense. Please see:
http://www.fukushima-sokai.net/ (English)
The group also has a (Japanese) Facebook page:
https://www.facebook.com/fukushimasokai
We very much hope that you will consider purchasing and reading the book, firstly for the insights it may give you into the significance of the Fukushima nuclear disaster and also to make a donation toward this important trial to help evacuate children to safer areas.
In fact, the group has now decided to link up with the Matsumoto Fund Boarding School Project for Fukushima Kids in order to take practical action to evacuate children from contaminated areas of Fukushima. Please see an English explanation a
http://www.kodomoryugaku-matsumoto.net/?page_id=614
Electronic copy: http://www.lulu.com/shop/nadesan-boys-mckillop-wilcox/fukushima-dispossession-or-denuclearization/ebook/product-21800492.html
EDITORIAL: Arrogance and complacency hallmarks of Abe’s leadership
Masahiro Imamura bows to reporters after submitting his resignation as reconstruction minister to Prime Minister Shinzo Abe on April 26.
Masahiro Imamura resigned April 26 as minister in charge of disaster reconstruction amid a public outcry over his latest gaffe concerning people affected by the devastating earthquake and tsunami of 2011.
“It was good that it happened over there, in the Tohoku region,” Imamura said of those catastrophic events at a fund-raising function for the ruling Liberal Democratic Party faction to which he belongs.
Imamura’s outrageous comment cast serious doubt on whether he truly comprehends the severity of the disaster, which left nearly 22,000 people dead, including cases attributed indirectly to the disaster, or missing.
He deserves to lose his job.
It was not the first time that Imamura had made an offensive remark about victims of the disaster. In early April, he stated that individuals who had voluntarily evacuated after the triple meltdown at the Fukushima No. 1 nuclear power plant were responsible for the situation they faced. “They are responsible for their lives. They can file a lawsuit or do other things (if they disagree with the central government’s position),” he said.
Coming from a minister who was duty-bound to show utmost sympathy for the plight of disaster victims, these remarks were simply unacceptable.
ABE’S COMPLACENCY GALLING
But Prime Minister Shinzo Abe allowed Imamura to remain in the post. It was a clearly misguided decision that reflected Abe’s complacency about his overwhelming political clout due to the ruling camp’s dominance in the Diet.
Imamura’s gaffes are part of a pattern that signal the powerful ruling coalition’s arrogance and conceit.
Yosuke Tsuruho, the minister for Okinawa affairs, is another member of the Abe Cabinet who sparked public outrage.
Asked to comment on an incident in which a riot police officer derided local protesters against U.S. military helipads by calling them “dojin” during a confrontation in Higashi, in the northern part of Okinawa Prefecture, Tsuruho said, “I personally cannot say with certainty that referring to somebody as ‘dojin’ amounts to discrimination.” Tsuruho reiterated that position later on. Dojin is a derogatory word referring to indigenous people, insinuating that they are uncivilized primitives.
Tsuruho has refused to retract his remarks.
Kozo Yamamoto, the state minister in charge of regional revitalization, offered another example when he labeled museum curators as a cancer that must be rooted out. In a lecture at a seminar for regional revitalization, Yamamoto blurted out: “The biggest cancer is curators. They don’t have any ordinary tourism business mind-set whatsoever. We have to get rid of these folks.”
Defense Minister Tomomi Inada made a lame and clumsy excuse when she retracted her remarks denying in the Diet that she had provided legal advice to Yasunori Kagoike, then head of Moritomo Gakuen, a scandal-tainted school operator, admitting that she actually did. “Those responses were based on my memory, so I do not believe I made false responses,” Inada said.
And then there is the matter of Justice Minister Katsutoshi Kaneda, who has repeatedly made contradictory remarks about proposed legislation to punish people who conspired to commit crimes and has kept relying on bureaucrats at his ministry to answer related questions in the Diet.
All these incidents signal a condescending attitude toward the public among members of the Abe Cabinet.
Their failure to see things from the viewpoint of the public is perhaps best demonstrated by the Abe administration’s strong-arm tactics in forging ahead with land reclamation work for a new U.S. military base off the Henoko district of the city of Nago, Okinawa Prefecture, in the face of fierce opposition from the prefectural government and residents.
Abe himself has made many questionable remarks.
One example came last week when he joked using the word “sontaku,” which roughly means conjecture about the wishes of another person to act in line with them. In the scandal over a controversial sale of state-owned land to Moritomo Gakuen at a deep discount, one core question is whether bureaucrats involved in the sale practiced “sontaku” to accommodate the implicit wishes of Abe and his wife, Akie.
Pointing out that a list of famous local specialties around the nation at a commercial outlet in Tokyo’s Ginza shopping district didn’t include products from Yamaguchi Prefecture, his electoral constituency, Abe said, “Please do sontaku about what I’ve just said,” evoking laughter from those he was addressing.
POLITICAL DOMINANCE TO BLAME
When a lawmaker of the main opposition Democratic Party cited in a recent Diet session the results of an opinion poll showing 80 percent of the respondents remain unconvinced by the administration’s explanations about the Moritomo Gakuen scandal, Abe dodged the criticism by pointing out that the same opinion poll also showed that the Cabinet approval rating stood at 53 percent. And he added, “You also know the approval ratings for my Liberal Democratic Party, and your Democratic Party.”
The string of deplorable remarks by ministers appear to echo Abe’s hubris.
Indeed, the Cabinet has been enjoying solid and steady public support. A recent Asahi Shimbun poll showed that this was mainly due to a sense among respondents that it “looks better” than anything the other parties could cobble together.
This suggests that Japanese voters remain somewhat resigned to the sad political reality that there is no opposition party with sufficient clout to replace the government led by Abe, who has built an overwhelming political power base.
Heightened tensions in East Asia, along with Japan’s solid economic performance, powered by growing employment, also appear to be contributing to the public’s unwillingness to change the political status quo.
Another factor behind Abe’s political dominance is the concentration of power in the prime minister’s office due to a series of reforms that started in the late 1980s.
The LDP leadership now has the power to decide the party’s official candidates for elections as well as the allocation of state subsidies received by the party and key bureaucratic appointments. There is widespread reluctance among LDP members to defy the party leadership.
Also, no group within the ruling party is sufficiently powerful to challenge Abe’s leadership. As a result, the tone of criticism within the party against ministers who speak out of turn, let alone Abe’s problematic words and deeds, is only getting weaker.
PARTY INCAPABLE OF SOUL-SEARCHING
The Abe administration’s arrogance and conceit have reached extreme levels.
“If we become complacent about our majority control and stop showing humility, we will instantly lose public support.”
This is what Abe said after he led the LDP to victory in the 2014 Lower House election and again after the Diet descended into turmoil over national security legislation.
But he refrained from making a similar comment after the ruling coalition scored a big win in the Upper House poll last year.
Was it because the LDP secured a majority in both Diet chambers for the first time in 27 years?
After Imamura’s resignation, a senior LDP lawmaker made an astonishing statement that showed the party had not undertaken any serious soul-searching.
Commenting on the development, LDP Secretary General Toshihiro Nikai said, “The mass media meticulously records all remarks made by politicians and calls for their immediate resignation if they utter just one improper sentence. What a situation. We would be better off without them (media).”
Did he mean that the news media, not Imamura, is to blame?
Since Abe became prime minister for a second time in late 2012, five members of his Cabinet have stepped down to take responsibility for their inappropriate actions or words.
Every time a member of his Cabinet was forced to bow out, Abe said that he, as prime minister, was responsible for the appointment that had turned out to have been a blunder.
Although he has apoligized to the public for these incidents, Abe has never taken specific action.
Any government becomes complacent and arrogant if it stays in power for too long.
It is up to the people, the holders of sovereign power, to use their voices and take actions to force the government to mend its ways.
Watchdog blasts Joyo reactor restart plan as ‘unacceptable’
The Japan Atomic Energy Agency’ Joyo experimental fast reactor in Ibaraki Prefecture
The nation’s nuclear watchdog has slammed the operator of the Joyo experimental fast reactor in Ibaraki Prefecture for its approach to safety concerns in seeking an early restart.
Shunichi Tanaka, chairman of the Nuclear Regulation Authority, on April 26 labeled the Japan Atomic Energy Agency’s proposal to bring the reactor back online as “absolutely unacceptable.”
The NRA on April 25 suspended its screening of Joyo’s restart plan based on stricter safety standards introduced after the 2011 Fukushima nuclear disaster.
“Has the JAEA seriously reflected on the accident at the Fukushima No. 1 nuclear power plant?” Tanaka asked at a news conference on April 26. “It said that explaining the restart (to municipalities) would take too much trouble. Its attitude toward the communities is wrong.”
The JAEA has applied to the NRA to restart the reactor with a plan to operate it with a thermal output of 100,000 kilowatts, rather than its full capacity of 140,000 kilowatts.
On April 25, JAEA officials explained that it would be able to restart the reactor faster by limiting the thermal output because that approach would save it time and effort in providing the necessary explanations to municipal authorities.
If the reactor operates with an output of 100,000 kilowatts, only local governments within a 5-kilometer radius of the reactor are required to produce evacuation plans.
However, when operating with an output of 140,000 kilowatts, local entities within a 30-km radius of the reactor are required to come up with evacuation plans.
Using a motorcycle analogy, Tanaka said the JAEA’s plan is tantamount to saying that the operator needs a “license for a 50cc bike as long as it drives a 750cc motorcycle at a speed of 30 kph or under.”
1 This Month
26 April – Chernobyl: Inside the Meltdown airs on National Geographic on Sunday 26th April from 4pm
29 April – Nuclear Expert Webinar #1 – Radiation Impacts on Families with Mary Olson and Cindy Folkers
- 12:15 PM MT – 1:45 PM MT
- Location: Virtual – REGISTER TODAY
4 May -West Suburban Peace Coalition to discuss Iran war at May Educational Forum
Monday, May 4, 7:00 – 8:00 PM Central Standard Time
Title: : How Trump’s Narrative Tries to Shape the Reality of the War on Iran.
Contact Walt Zlotow, zlotow@hotmail.com 630 442 3045 for further information
14 May – online event From Bombs to Data Centres: the Face of Nuclear Colonialism
Pine Ridge Uranium is the real threat, not Tehran- Tell Burgum: Stop the Extraction.
Chernobyl: The Lost Tapes – A good documentary on Chernobyl on SBS available On Demand for the next 3 weeks– https://www.sbs.com.au/ondemand/tv-program/chernobyl-the-lost-tapes/2352741955560
To see nuclear-related stories in greater depth and intensity – go to https://nuclearinformation.wordpress.com
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