Summary ofIAEA-MOE Experts’ Meeting on Environmental Remediation of Off-Site Areas after theFukushima Daiichi Nuclear Power Station Accident
Tokyo, Japan
4 – 5 February 2016

The 1st IAEA-MOE Experts’ Meeting on Environmental Remediation of
Off-Site Areas after the Fukushima Daiichi Nuclear Power Station Accident was hosted
by the Ministry of the Environment of the Government of Japan (MOE) in Tokyo from4 – 5 February 2016. The objectives of the meeting were i) to discuss the current status(progress, achievements, challenges and future endeavours) of environmental
remediation activities taking place in off-site areas affected by the accident at theFukushima Daiichi NPP; ii) to provide assistance to Japan, as appropriate, inconsidering approaches that can foster further progress with the environmental
remediation works currently being undertaken or planed; and iii) to collect the extensive
experience accumulated so far by the MOE in the implementation of the remediation
activities with the aim of sharing relevant findings with the international community.
From the side of the IAEA six experts took part in the meeting including threeinternational experts and three internal staff members. From the Japanese side, themeeting was attended by officials of the MOE.
The meeting covered a wide range of topics and was organised in such a waythat presentations from Japanese representatives were followed by presentations
provided by IAEA experts. After each pair of presentations – addressing a specificpre-determined topic – discussions followed. The series of presentations given by theMOE were aimed at addressing the results of different activities implemented by thenational and local governmental authorities, highlighting progress made to-date and theissues that Japan is/has been facing in conducting remediation works. The presentations
made by the IAEA experts consisted of a compilation of international knowledge andgood practices in each of the discussed areas.
The IAEA team noted the continued and significant efforts put in place so far by
Japan in the remediation of the off-site areas and also the results achieved with thiseffort. It was particularly noted and acknowledged that progress has been achieved
through the remediation works undertaken both in the Special Decontamination Area(SDA) and in the Intensive Contamination Survey Area (ICSA).
One of the challenges presently faced by the MOE, as a result of the remediationof the affected areas, deals with the need to manage the large amount of contaminatedsoil and waste generated during the remediation activities. A refined inventory ofcontaminated soil and waste to be treated and subsequently stored in the Interim Storage1

Facility has been produced. In addition, the MOE has been investigating techniques andtechnologies to reduce the volume of generated soil and waste prior to disposal. The
technologies that the MOE has been assessing include soil segregation (classification),chemical treatment, and heat treatment. The MOE has also been considering therecycling of the residual materials that meet the criteria that will be established to allow
for this practice. One of the experts’ presentations focused on technical aspects related
to soil segregation methods, considerations on the overall volume reduction that can beachieved to minimize the amounts to be disposed, and the reduction of the associatedcost of transportation and disposal.
It has been suggested that for those sites with potentially high amounts ofcontaminated soil to be dealt with as well as for the existing amounts accumulated in
temporary storage sites, it would be beneficial to establish criteria (that will allow forsoil recycling) prior to the clean-up activities or implementation of soil volume
reduction methods (prior to permanent disposal).
The IAEA team was introduced to the English draft of the “DecontaminationReport” (published by the MOE in March 2015, in Japanese). The report provides
comprehensive collections of “knowledge, experiences, and lessons obtained with thedecontamination efforts.” It was recognized that the report is a key document tosupport the international community in learning from the extensive experience of Japan(thereby gaining a better perspective of the effectiveness of different decontaminationapproaches) as it addresses pre-existing deficits in the available international literature(particularly for urban environments) prior to the Fukushima accident. The document
provides the results obtained through decontamination works applied to different typesof surfaces contaminated with radioactive material in the aftermath of a
nuclear/radiological accident. Several areas of further work, mostly relevant to urban
environments, can be summarized as below:
1) Improved information about decontamination factors achieved for specifictechniques applied to specific materials or classes of materials would be usefulto achieve better targeted clean-up efforts.
2) Greater detail about the application of a specific method with a view toreproducing the obtained results and consequently permitting the application of
the technique with a satisfactory degree of reproducibility.
Additional information to be gathered in future remediation activities will beinvaluable to the international community if detailed information/data on the topics
listed below can be addressed:
1) The fraction of radionuclide that is fixed onto loose particulate and that is
subsequently chemically bonded onto structural materials of buildings, roadways,etc.
22) Distribution of radionuclides within the sewer systems, wastewater treatment
plants and drinking water supplies systems.
3) Data to distinguish between decontamination factors measured for different
types of, concretes, asphalts, composite shingles, etc.
4) Established Standard Operating Procedures (SOPS) and associated lessons’learned and the effect of evolving worker proficiency in decontamination
performance.
The current status of remediation activities in forests as well as plans for future
measures were explained by the MOE. It has been clarified that attention is being paid
to the possibility of restarting forestry and other activities in forests upon the return ofthe evacuees. The IAEA presentation stressed that remediation works in forests require
thorough consideration on the important functions of the forest ecosystem. One of theexamples in this regard was the key role of forests in preventing soil erosion andsubsequent radionuclide transport into downgradient environments. The IAEA
presentation also highlighted the key criteria that should govern the evaluation ofremediation measures in the context of justification and optimization, namelyeffectiveness in reducing radiation dose to local people, acceptability, costs,environmental impacts, technical feasibility, radiation protection of workers, and wastemanagement. With all these aspects taken into consideration it was noted that theapproaches used by the Japanese authorities on the decontamination of forest seemed tobe in line with internationally accepted good practices. A lot of good data have been
produced and this amount of information allows for a proper assessment of the mainprocesses taking place in forest ecosystems which can inform planning of future actions.
The active discussions during the meeting highlighted the potential benefit offurther activities to be implemented by the IAEA that can be useful to its Member States,e.g., the establishment of a decision supporting tool that incorporates considerations on
waste volume reduction options and associated assessment of its impact on final
disposal. In this regard aspects to be considered include: characteristics and inventory ofthe current and forecasted amounts of waste and a toolbox of available waste treatment
technologies including potential recycling options.
The Waste Estimation Support Tool (WEST) developed by US EPA and anyother relevant tools may be a potential platform that can support this development
provided some modifications are incorporated in the existing system. The modifications
include the following: i) updating decontamination information based on the available
results and experience (such as effectiveness of decontamination procedures andassociated waste generation), ii) extending the options of waste treatment technologies,and iii) generating a contamination map in tool-specific file format. The robustness andperformance of the tool could then be verified by applying the system in areas where3

decontamination works have been previously completed. Its application in the planningof future remediation activities is also a potential option that can be further explored. If
the results are satisfactory, this tool could contribute to the improvement of theinternational community's capabilities to deal with environmental remediation works inpost-accident situations.
As a final note the key role of communication of the outcomes of theremediation works to different stakeholders was once again appreciated and valued. In
this regard it was noted that it is very important that relevant information is constantly
transmitted to the public using appropriate and clearly defined terminology andpresenting ongoing and planned activities in a life-cycle perspective, and that the views
and concerns of the affected community are also captured and addressed.
In conclusion, the participants appreciated the fruitful discussions at the meetingand would welcome that the IAEA and the MOE continue to organize similar meetings
on a regular basis.

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