Development of solidification techniques with minimised water content for safe storage of secondary radioactive aqueous wastes in Fukushima

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering

Abstract

The processing of contaminated water from the TEPCO Fukushima Daiichi Nuclear Power Plant (NPP) results in a large amount of secondary aqueous wastes. They are highly radioactively contaminated, and those produced at the early stage of the processing also contain significant amounts of sea salt. Due to the significant radioactivity and water content, hydrogen gas is generated from these wastes, and their long-term storage faces the potential risk of not only leakage, but also explosion and fire. For the safe storage of these wastes, they must urgently be converted into a form that has a reduced risk of leakage as well as a minimised fire risk due to hydrogen gas generation. Thus, the proposed project aims to develop a solidification technique with minimised water content for the safe storage of secondary aqueous radioactive wastes from the Fukushima Daiichi NPP.

The project has strong bilateral UK and Japan links, incorporating expertise from both universities and the Japanese Atomic Energy Agency. The joint research will focus on the immobilisation of secondary aqueous wastes, which are problematic since they incorporate a large number of compounds (e.g. 90Sr, Mg(OH)2, NaCl), making their chemistry complex. We will develop a novel solidification technique, through heat-treatment, based on magnesium phosphate and calcium phosphate cement chemistry that will result in a safe, passive wasteform. This wasteform will be fully characterised and its irradiation stability and long-term aqueous stability will be determined, to develop an understanding of its behaviour under further interim storage or final geological disposal conditions. The success of the project will lead to improved public and government confidence in the decommissioning and waste management practises at the Fukushima Daiichi NPP, in addition to supporting UK nuclear waste decommissioning strategies.

Planned Impact

The largest, and no doubt the most important impact that the successful outcome of this research can make, is the actual application of the developed solidification technology for the secondary aqueous wastes arising from the processing of the contaminated water at Fukushima Daiichi Nuclear Power Plant. As such, we identify four main beneficiaries from the research: Japanese Governmental bodies; Japanese nuclear community (i.e. public); and Japanese and international academic and industrial nuclear communities. In detail:

- Japanese Governmental bodies, such as the Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF) and the International Research Institute for Nuclear Decommissioning (IRID) will benefit from close communication of our research progress and outcomes through the Japanese research partners. This will ensure that the proposed research continues to align with the recently published Fukushima Roadmap to decommissioning.
- The large scale demonstration of the heating solidification process will help to improve Japanese Governmental and public confidence in the Fukushima Daiichi NPP site decommissioning. Improved public confidence will also be realised in the UK, which will ultimately benefit the governmental bodies responsible for nuclear waste management (e.g. Nuclear Decommissioning Authority) and nuclear waste disposal (Radioactive Waste Management Limited).
- The dissemination of the research outcomes of this proposal to the international community and the nuclear academic community in Japan will us to promote the research and attract further collaborators, building an extended network for the development of decommissioning technologies using a novel cementitious material approach. For example, we will disseminate our research at the Atomic Energy Society of Japan (AESJ) biannual meeting. The UK-Japan based research will therefore help to promote an internationally-leading research community in the field of nuclear power plant decommissioning, which will have impacts not only to those countries participating, but also specifically to support the UK Government's ambition to promote nuclear power research and development. This will have far-reaching impacts to the UK economy, the environment and society.
- In accordance with the EPSRC and STFC review of Nuclear Engineering, this research will produce highly skilled and knowledgeable post-doctoral scientists for potential recruitment by the nuclear industry, with awareness of both UK and Japan decommissioning issues.
 
Description - Radioactive wastes from processing of contaminated water is difficult to encapsulate with conventional cement matrices, due to the potential hydrogen gas generation originated from the radiolysis of waster content by the radioactive waste elements (strontium in this particular case). - It was possible to use phosphate-based cement to produce a cement matrix with reduced water content, thus reducing the risk of hydrogen gas generation. - The simulated aqueous wastes were successfully incorporated into the developed phosphate-based cement matrix. The phosphate-based cement wasteform produced in the project were able to supress the generation of hydrogen gas under irradiation. - Dissolution of non-radioactive strontium from the phosphate-based cement matrix was highly limited, showing the superior property of the developed cement matrix. - This project was awarded the very top "S" grade by the Nuclear Safety Research Association in Japan in 2019 for its achievement.
Exploitation Route The research outcomes will be reviewed by the relevant authorities in Japan, to contribute to the contry's decision making for the management of radioactive wastes arising from the decomissioning activities in Fukushima Daiichi Nuclear Powerplant.
Sectors Construction

Energy

Environment

URL https://www.kenkyu.jp/nuclear/evaluation/h31/pdf/a29_3_4.pdf
 
Description This is not a direct finding of the project, but it has received a significant attention from the research community, governmental body and regulatory organisation in Japan. This resulted in participating the educational programme organised by the National Institute of Technology, Fukushima College in Japan. They have developed a programme of study for their students looking specifically at the decommissioning of nuclear power plants and environmental recovery - a topic of particular significance to the Institute and local people in the wake of the damage caused to the Fukushima Daiichi Nuclear Power Plant by the earthquake and tsunami that hit Japan on 11 March 2011. The ongoing decommissioning of the facility and environmental clean up remain a significant priority for the Japanese government, and the training of the next generation of engineers is a vital part of this development programme commissioned by the Nuclear Regulatory Agency in Japan.
First Year Of Impact 2018
Sector Education
Impact Types Societal

Policy & public services

 
Description Member HM Goverment Committee on Radioactive Waste Management
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
 
Description EPSRC UK-Japan Civil Nuclear Phase 3
Amount £600,000 (GBP)
Funding ID EP/P013171/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2016 
End 03/2019
 
Description Engineering And Physical Science Research Council (Epsrc) IAA
Amount £23,855 (GBP)
Funding ID R/143154 
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 04/2015 
End 09/2015
 
Description Safe, efficient cementation of challenging radioactive wastes using alkali activated materials with high-flowability and high-anion retention capacity
Amount £253,537 (GBP)
Funding ID EP/T013524/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2019 
End 04/2022
 
Description Development of versatile cementitious matrix for Fukushima's decontamination wastes 
Organisation Japan Atomic Energy Agency (JAEA)
Country Japan 
Sector Public 
PI Contribution We have hosted a PDRA from JAEA to conduct a feasibility investigation on a new cementitious matrix for radioactive waste encapsulation.
Collaborator Contribution JAEA provided a PDRA to undertake the titled project.
Impact This collaboration formed the foundation of the awarded project. The direct outcomes of the project have been presented at two conferences shown below, one of which won a poster prize. Keita Irisawa, Amar Kamarulzaman, Ines Garcia-Lodeiro, Yoshihiro Meguro, Hajime Kinoshita, "Effect of phosphate modification on incorporation of caesium nitrate by calcium aluminate cement," Oral presentation at 4th Mechanisms and Modelling of Waste/Cement Interaction, Switzerland, May 2016. Keita Irisawa, Sze Wing Yeung, Patcharapak Suriwong and Hajime Kinoshita, "Effects of composition on calcium aluminate phosphate cement for caesium nitrate incorporation," Oral and poster presentation at 35th Cement and Concrete Science Conference, Aberdeen, August 2015
Start Year 2015
 
Description Electric leaching tests on cementitious nuclear wasteforms 
Organisation University of Kyoto
Department Laboratory on Innovative Techniques for Infrastructures
Country Japan 
Sector Academic/University 
PI Contribution Partnership within the large project currently on-going (Development of solidification techniques with minimised water content for safe storage of secondary radioactive aqueous wastes in Fukushima), originated from a smaller collaboration between Sheffield- Hokkaido started in 2014. We provide the materials to test at Kyoto to be tested using their facility of electric leaching.
Collaborator Contribution They conduct testing on the materials provided from us - simulated cementitious wasteforms aiming to apply for the radioactive secondary wastes arising from the decontamination of water in Fukushima.
Impact This is collaboration between materials scientists and civil engineers. The outcomes of this specific collaboration is yet to be established, but the outcomes of the overall project are listed elsewhere.
Start Year 2015
 
Description Training of next generation nuclear engineer in Fukushima 
Organisation Fukushima National College of Technology
Country Japan 
Sector Academic/University 
PI Contribution As an official overseas partner of the consortium, we host the students on this programme in our group to provide training on research and professional skills via internship.
Collaborator Contribution With a support from Japanese Government, Fukushima National College of Technology is strategically fostering talented students in Fukushima region to educate engineers of next generation specialising in nuclear waste management and reprocessing who can meet the demand of the society and industry. They will lead the programme, select students and provide opportunities of trainings through internship and visits within Japan.
Impact This partnership is yet to produce outputs.
Start Year 2018
 
Description BBC 5 Live / BBC Cambridge / The Naked Scientists podcast 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Interviewed for BBC Radio Cambridge and the Naked Scientists podcast on radioactive waste disposal.
Year(s) Of Engagement Activity 2020
URL https://twitter.com/NakedScientists/status/1246857392463269888
 
Description CNN interview - Fukushima contaminated water release 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Gave CNN interview on the topic of radioactive water stored at the Fukushima site.
Year(s) Of Engagement Activity 2020
URL https://edition.cnn.com/2020/10/24/asia/japan-fukushima-waste-ocean-intl-scli/index.html
 
Description CoRWM presentation at NDA Integrated Waste Management Programme Stakeholder Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Gave a talk on behalf of the Committee on Radioactive Waste Management at the Nuclear Decommissioning Authority's Integrated Waste Management Programme Stakeholder Workshop.
Year(s) Of Engagement Activity 2020
URL https://www.marickpartners.co.uk/iwmp/
 
Description Cross-disciplinary Seminar, Research Institute of Nuclear Engineering, University of Fukui 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Provided a series of 3 lectures on the current research activities at 94th Cross-disciplinary seminar of Research Institute of Nuclear Engineering, University of Fukui (01 May, Tsuruga, Japan 2017). Approximately 50 audience, both students and staff participated, and discussed the waste management research for recovery of Fukushima.
Year(s) Of Engagement Activity 2017
 
Description Engineering Matters Podcast 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed for Engineering Matters podcast on radioactive waste decommissioning and disposal
Year(s) Of Engagement Activity 2020
URL https://engineeringmatters.reby.media/2020/03/13/50-dealing-with-nuclear-waste/
 
Description Financial Times interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed for Financial Times article "UK returns to grappling with toxic nuclear waste dilemma" - quoted in main article.
Year(s) Of Engagement Activity 2021
URL https://www.ft.com/content/2321bfae-839a-468f-b933-d699b6ff6864
 
Description Fukushima College internship 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact 5 students and 3 academic staff visited our department from Japan through Fukushima College, see our facility, had discussion on our research, and discussion with our undergraduate students.
Year(s) Of Engagement Activity 2022
 
Description Hosting visitors from National Institute of Technology, Fukushima College 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact We hosted 3 undergraduate students and 1 academic staff from Fukushima College (26 March, 2019). Tthrough the laboratory tour and discussion, the visitors had a chance to see the research activities in the decommissioning of nuclear power plants and environmental recovery, currently undertaken at Sheffield. This was a part of the training of the next generation of engineers commissioned by the Nuclear Regulatory Agency in Japan.
Year(s) Of Engagement Activity 2019
 
Description Hosting visitors from National Institute of Technology, Fukushima College 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact The representatives from Fukushima College (3 undergraduate students and 2 academic staff) visited the Department of Materials Science and Engineering at The University of Sheffield, to see the research activities in the decommissioning of nuclear power plants and environmental recovery, currently undertaken at Sheffield. This was a part of the training of the next generation of engineers commissioned by the Nuclear Regulatory Agency in Japan. (Visit 1: March 2018, Visit 2: September 2018, Visit 3, March 2019)
Year(s) Of Engagement Activity 2018,2019
URL https://www.sheffield.ac.uk/materials/news/fukushima0703-1.767398
 
Description IAEA School on Waste Cementation 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I presented 6 lectures over 4 weeks in the Joint ICTP-IAEA International School on Radioactive Waste Cementation, jointly organized by the IAEA and the Trieste, Italy-based Abdus Salam International Centre for Theoretical Physics (ICTP). Several of these lectures were related to the outcomes of this project. The School was held as a virtual event and attended by more than 60 practitioners, policymakers and students from 30 countries. This is a flagship event of the International Atomic Energy Agency. As a result of my participation in this event, I was also invited to join the Steering Committee of the IAEA International Predisposal Network.
Year(s) Of Engagement Activity 2020
URL https://www.iaea.org/newscenter/news/joint-iaea-ictp-virtual-school-highlights-global-interest-in-ra...
 
Description International seminar on Decommissioning of Fukushima Daiichi Nuclear Power Station 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Through the group discussion and debates, as well as presentations of the leading experts from US, France, UK and Japan, this seminar inspired young researchers and postgraduate students in Japanese research institutions and industry in the area of decommissioning of nuclear power plants.
Year(s) Of Engagement Activity 2018
URL https://fukushima.jaea.go.jp/en/hairo/frc/frc02_20180926.html
 
Description Internship from National Institute of Technology, Fukushima College 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact We hosted 5 undergraduate students from National Institute of Technology, Fukushima College in Japan (07-15 March 2019). The National Institute have developed a programme of study for their students looking specifically at the decommissioning of nuclear power plants and environmental recovery, a topic of particular significance to the Institute and local people in the wake of the damage caused to the Fukushima Daiichi Nuclear Power Plant by the earthquake and tsunami that hit Japan on 11 March 2011. The ongoing decommissioning of the facility and environmental clean up remain a significant priority for the Japanese government, and the training of the next generation of engineers is a vital part of this development programme commissioned by the Nuclear Regulatory Agency in Japan. We provided a one-week internship for nuclear waste management research through the site visit, laboratory tour, desk-top assignment and presentation.
Year(s) Of Engagement Activity 2019
 
Description Invited talk at the IChemE 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Gave invited talk at IChemE webinar on the application of synchrotron x-ray techniques to understand radioactive materials.
Year(s) Of Engagement Activity 2021
URL https://www.icheme.org/membership/communities/special-interest-groups/nuclear/events/24-02-21-new-op...
 
Description Mirage news article on cement technetium 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed for Mirage News article on cement-technetium interactions
Year(s) Of Engagement Activity 2020
URL https://www.miragenews.com/ettringite-cements-its-potential/
 
Description Online seminar for Fukushima College internship 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact Fukushima College organises international internship for future engineers (undergraduate students) who are interested in nuclear technology. Doe to the COVID-19 situation, the internship was mostly conducted online this year. We contributed to this by providing a seminar on nuclear waste management.
Year(s) Of Engagement Activity 2021
 
Description Presentation to Allerdale Borough Council on behalf of CoRWM 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact Delivered presentation to Allerdale Borough Council (part of the Allerdale Geological Disposal Facility Working Group) about CoRWM and support available from CoRWM during the GDF siting process.
Year(s) Of Engagement Activity 2021
 
Description UK - Japan Civil Nuclear Energy Programme: Meeting and Collaboration Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The event hosted total of ~50 researchers from Japan and UK, initiating the UK-Japan collaboration in civil nuclear energy research. The UK-Japan collaborations (fundend by EPSRC) from Phase 1 and Phase 2 were invited to give a presentation as a case study, to demonstrate how they developed the project, how they applied and how they conducted the actual project. Based on these, participants had substantial discussion to identify the areas of research and potential partners beneficial both for Japan and the UK sides.
Year(s) Of Engagement Activity 2019