Radiation Monitoring and Remediation
after Fukushima Daiichi NPP accident- The IAEA’s assistance and support
to the Fukushima Prefecture -Summary of the discussions
Miroslav PINAKTechnical Leaderof the IAEA-Fukushima Prefecture Cooperative ProjectIAEA

Origin and scope of cooperation
Following the accident at TEPCO’s Fukushima Daiichi
nuclear power plant, the IAEA and the Prefectureagreed to cooperate on radiation monitoring andremediation. The Practical Arrangements on thiscooperation aim to provide broad and extensive
assistance in the Prefecture in these two areas,
complementing existing Japanese activities andproviding immediate assistance and support that
directly benefit those living in the Prefecture.

Radiation monitoring & mapping• including the application of environmental mapping technology by using
unmanned aerial vehicles, and using radiation monitoring data to develop maps
to be made available to the public

Remediation & decontamination• Off-site decontamination, including in analyses of environmental monitoring
results and the exploration of exposure pathways so as to reduce or avoid
exposure

Management of radioactive waste• The management of radioactive waste and on management methods of lowlevel radioactive waste from off-site decontamination activities2

10 years IAEA assistance to the Fukushima
Prefecture on radiation monitoring, remediationand decontamination in off-site areas* Subject covered in the beginning of assistance3Remediation &Decontamination Session

4Topics covered by FCP1, FIP1 and FIP3
• Radiocaesium (Cs-137 and Cs-134) in freshwater systems––––––

Suspended and dissolved radiocaesium in water
Source of radiocaesium in sediments
Time-dependence of radiocaesium in river water
Loss of radiocaesium from catchments
Simulation of radiocaesium in rivers (TODAM model)
Radiocaesium microparticles• Decontamination work in rivers• Options for countermeasures in freshwaters• Decontamination work in the terrestrial environment• Dissemination of results
5Key findings: Behaviour of radiocaesiumin aquatic systems•

Environmental and climatic conditions in the Fukushima and Chornobyl
regions are quite different but the behaviour of radiocaesium in theenvironment is similar.
–

Strong sorption of caesium to solids.

–In fresh waters, most of the Cs-137 is found in suspended or bottom
sediments•

Survey data indicate a continuous decline in radiocaesium concentrations inrivers since 2011. Decline observed in the Prefecture and in other parts of
the world agree reasonably well.

•Predictions using a simulation model for dynamics in rivers (TODAM) show
agreement with measurements under base- and high-river flow conditions. 6

Key findings: Behaviour of radiocaesiumin aquatic systems•

In the Prefecture, loss of Cs-137 due torun-off depends on the land-use. The loss
is low – about 1% in the year of deposition
and well below 1% per year thereafter.
–General agreement with experience inother countries•

Environmental tracers, such as ∂13C, canserve as powerful tools to trace Cs-137 in
the environment.

•Small number of CsMPs have been found- low levels of radiocaesium bound tothem. Cs-137 bioavailability is likely to be
low and no significant impacts are likely.
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Key findings: remediation of terrestrial
environment•

Countermeasures that control release of Cs-137 into surface waters(e.g. decontamination of upstream environments) can be an effective
approach to prevent accumulation in sediments in aquatic systems•

Gamma dose rates in forests, on agricultural lands and residential areas
after decontamination are reduced by about 30-50 %, both in Chornobyland Fukushima•

For reducing Cs-137-levels in crops, a similar range of techniques wasapplied after the Chornobyl and Fukushima accidents. Wherecomparable, reduction factors are similar

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Key findings: Control of dispersion in dynamic
aquatic systems:
engineering measures• Aquatic systems are complex and very site specific• Large-scale engineering measures are costly and often difficult toimplement.
• Natural sediment traps worked well e.g., at the Yokokawa dam and at
the Kiev reservoir in Ukraine.
– Calm waters with low water flows leading to high sedimentation• Removal of bottom sediments is an effective and globally applied
measure for remediation of water bodies (including demonstration testin the Prefecture).
• Removal of riverside sediments and vegetation (demonstration test in
Kami-Oguni river) reduced dose rates by a factor of about 2: thisreduction persisted and was not affected by typhoons and flooding.

9Discussion topics: future questions•Human activities, land use, the existence of dams and decontamination
activities within a river basin influence the transfer of radiocaesium throughriver systems– Future monitoring will show the impact of future changes and clarify thelong-term dynamics in the aquatic environment– Stable C tracers could continue to be used to help predict fluxes ofsediments and influence of local conditions•

Interest in using the TODAM simulation model for predicting future trends ofradiocaesium in rivers – could be useful for exploring impact of high waterflow rates and impact of climate change.

•It was suggested that further work on evaluating the cost-effectiveness ofcountermeasures compared to natural attenuation could be used to informfuture work e.g. ,decontamination of riverbanks
10Waste Management Session

11Topics
Covered by
FCP2 & FIP5

• FCP2: Management of Waste fromRemediation Activities– Technical Guidelines for TSS– Safety Assessment for TSS• FIP5: Study of Proper Treatmentof Waste containing RadioactiveMaterial– Treatment of Waste Containing
Radioactive Material– Municipal Waste Landfills in Japan– Safety Assessment for Municipal
Landfills– Dose Modelling Aspects
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Key Findings (FCP2 & FIP5)•

After the 2011 Fukushima Daiichi accident, enormous amounts of materials weremanaged as radioactive waste•

A cumulative total of over 1000 Temporary Storage Sites (TSS) were establishedin the Prefecture based on “Technical Guidelines”.

•The waste was later moved to Interim Storage Facilities•

The IAEA assisted the Prefecture by:–Explaining IAEA Safety Standards–

Reviewing the Technical Guidelines–Sharing expertise and experiences from outside Japan–

Training the Prefecture on assessing the safety of TSS–

Reviewing and advising on Prefecture’s research on Cs in incineration ashes–

Training the Prefecture to assessing the safety of Cs-containing ash in landfills–

Advising on the presentation and communication of information
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Key Points (FCP2)•

The Prefecture’s capabilities on radioactive waste
management were significantly enhanced•

The Technical Guidelines worked as proceduresfor safe waste management, comments wereprovided to the Prefecture on all the versions ofthe Technical Guidelines (version 6 is the actualversion)•Support was provided by the IAEA to the Prefecture for the safety assessment ofTemporary Storage Sites for normal and accidental situations and for all phasesof development•

Assessed doses during operation of TSS and after waste removal are well below
relevant dose limits and long-term goals
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Key Points (FIP5)• The incineration of contaminated materials (e.g. Waste from outdoorsources) produced Cs-contaminated incineration ashes• The safety of landfilling ashes, containing up to 8000 Bq/kg of Cs, at
one site was assessed using IAEA’s “Clearance Tool” software,
specifically adapted to conditions in Japan• For the amount of radioactive Cs in ash disposed of, the calculated
additional doses to residents living near the landfill in the future are verylow• Even if people live on the landfill in the future and drink water from thesite, the doses are estimated to be below 1 mSv/year• To guarantee representativeness of the results in the Prefecture, furtherwork would be needed to assess other landfill sites

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Discussion Topics• Strategic Environmental Assessment (SEA)– Could SEA as applied to landfills in Japan be applied elsewhere in the world?
SEAs are done quite widely for landfills (e.g. in the U.K.), so in principle, yes, theapproach used in Japan is used elsewhere. If radioactive waste is to bedisposed, the safety case is required as well as is SEA.

• Landfilling of radioactively contaminated waste– What stakeholder management was done? Positions of stakeholders to waste
disposal need to be assisted by scientists who have understanding of publicperception.

• Public acceptance– The FCP2 and FIP5 projects addressed the safety of temporary storage and of
landfill disposal, but was there a change in public perception following theseactivities of demonstrating the safety of those facilities? Briefings on the TSS
were given to the public and the municipalities on the safety of the facilities.

16Discussion Topics• ‘On-site’ waste storage– There were some 190,000 ‘on-site’ storage sites (storage in decontaminationsites) where waste was kept before transport to TSS. Sometimes on-site storage
lasted for several years (e.g. residential gardens). Was this covered in the IAEA –Prefecture discussions? The number of on-site storage sites has reduced (to～770) due to the removal of waste to interim storage facilities, but there are indeed
some that remain. The Technical Guidelines cover on-site storage and werereviewed by the IAEA, but the main focus of the collaboration was on TSS.

• Incineration– How efficient is the incineration and what is the effect of combustion temperatureon the distribution of Cs in ashes? Tests with radionuclides are not being done at
the actual incinerator facility, but instead simulations are being done.

17Monitoring Session

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Topics
FCP3

FIP2

FIP4

•Forest•Mushroom•Fish• Survey ofradionuclide
movement
with wild
animal• Walkingsurveys• Environmental
mapping2013 - 2022

2013 - 2022

2013 - 2016

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Findings: radiocaesium in forests(FCP3 <forest, mushroom>)•Radionuclides deposited in the forests of the Prefecture are effectively
retained within the forest ecosystem and the likelihood of transfers ofradiocaesium to agricultural land appears to be low•

Forest maintenance procedures are very effective at retaining
radiocaesium within forests•

The presence of clay minerals in the underlying forest soils has
chemically bind the radiocaesium and limit its transfer to vegetation•

Measures have been implemented to restrict the radiation exposure offorest workers

20Findings: Monitoring in forests(FCP3 <forest, mushroom>)•Radiation monitoring in forest may be necessary for many moreyears•

Optimization of forest monitoring is needed moving forward due
to available resources•

How long will monitoring of forests and forest products beneeded?

21Findings: monitoring of wild foods(FIP2, FCP3)•Activity concentrations in wild foods are variable but there are highconcentrations still being measured in 2022 that are >100 Bq/kg.

•Decline in Cs concentrations in wild mushrooms and other wild foods isslow and restrictions may be required for many years for some species
and in some areas– so monitoring will need to continue in the long-term to provide
surveillance and reassurance and to remail vigilant to changes inforest systems•

Non-destructive analysis method has been tested for matsutake
mushrooms to avoid destroying expensive mushroom species•

Although significant progress has been made over the past decade in
lifting distribution restriction for inland fish, there are still restrictions onsome fish species in some areas, and recreational fishing are not allowed
to resume.
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Discussion and possible
future tasks•

If Prefecture’s approach to GoJ’s relevant authorities to lift
restrictions needs support (wild animal’s flesh, wildmushroom), the IAEA is expected to provide technicaladvice and assistance, concerning existing international
practice•

The IAEA informed about existing effort towards reference
levels to be used in international trade, which may also
eventually serve for national decisions

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Information Dissemination
Session24

Topics•

IAEA’ s assistance on information dissemination interlinks with all theareas and activities of cooperation:– remediation of the environment– management of radioactive waste– radiation monitoring

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Key points•

IAEA’s assistance was provided on effective ways to communicate information to
the public in a timely and understandable manner•

Methodologies and expertise provided were based on global experience indealing with accidental releases•

The most efficient way of getting messages across is to move away from oneway information dissemination to engagement of stakeholders•Concrete communication products were developed in order to better informaudiences about radiation levels, risks and the radiation levels in the Prefecture•

The Prefecture websites has been revised in line with IAEA recommendations,for better user experience, higher search engine optimization therefore for higher
impact•Google Analytics tool was used to obtain quantitative data on visitor rate,retention, revisiting rates, drill down and bounce rates
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Key points•

An important task is to increase trust of the general public in the Prefecture
itself, in Japan and abroad, enabling them to make informed opinions•Requires definition of target audiences, appropriate communication goals
and tools and messages•

It is essential to communicate accurate messages to the target audience
without using too specific scientific concepts•To make outreach products easily understandable it was recommended tosimplify language and to use infographics, graphs, animations, videos, etc.

•Lessons learned were: to simplify information presented on the page of thewebsite, to build information architecture/taxonomy, include more actionable
items on main page (surveys, videos…), to focus on fresh news on regularbasis27Key points• Radiation Safety Navigator was introduced as the newIAEA’s online tool for effective communication about
radiation safety. This tool can be utilized by the Prefecture,for example, in conveying messages about radiation doses.

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Discussion topics
Involvement of citizens• Was there any involvement of the citizens in measurement of radiation? As aresult of citizen’s need, municipalities distributed dosimeters to the citizens sothat they can measure radiation doses in the area.
Searching feedback• Was there any feedback from mushroom pickers/distributors and hunters on thebrochures developed for them? The Prefecture is in the process of receiving
feedback. Every year the content of these brochures will probably need berevised.
Expansion of currently available brochures• Could an option to expand current series of brochures could be creating
additional brochure on for example the wild plants?
 Prefecture’s standpoint-Prefecture has already posted information about wild plants on website.
Unlike wild mushrooms, there is no plan to make and publish brochure
regarding distribution restrictions on edible wild plants as it is complicated.

29Currently available information
 IAEA website
https://www.iaea.org/topics/radiation-protection/cooperation-fukushima-prefecture Prefecture website
https://www.fukushima-kankyosozo.jp/research.html
https://www.fukushima-kankyosozo.jp/eng/index.html

30Summary Reports (2013～2022)• The IAEA and the Prefecture are currently working
together on summarizing results of 10 years
cooperation and future plans• To be summarized as “Summary Reports”• Both in English and Japanese• Both FCP and FIP• To be published in the websites of the IAEA and thePrefecture in spring 2023
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Thank you very much foryour kind attention!