Nuclear News

What should countries do with their nuclear waste?

A new study by MIT researchers analyzes different nuclear waste management strategies, with a focus on the radionuclide iodine-129

Massachusetts Institute of Technology

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

One of the highest-risk components of nuclear waste is iodine-129 (I-129), which stays radioactive for millions of years and accumulates in human thyroids when ingested. In the U.S., nuclear waste containing I-129 is scheduled to be disposed of in deep underground repositories, which scientists say will sufficiently isolate it.

Meanwhile, across the globe, France routinely releases low-level radioactive effluents containing iodine-129 and other radionuclides into the ocean. France recycles its spent nuclear fuel, and the reprocessing plant discharges about 153 kilograms of iodine-129 each year, under the French regulatory limit. 

Is dilution a good solution? What’s the best way to handle spent nuclear fuel? A new study by MIT researchers and their collaborators at national laboratories quantifies I-129 release under three different scenarios: the U.S. approach of disposing spent fuel directly in deep underground repositories, the French approach of dilution and release, and an approach that uses filters to capture I-129 and disposes of them in shallow underground waste repositories.

The researchers found France’s current practice of reprocessing releases about 90 percent of the waste’s I-129 into the biosphere. They found low levels of I-129 in ocean water around France and the U.K.’s former reprocessing sites, including the English Channel and North Sea. Although the low level of I-129 in the water in Europe is not considered to pose health risks, the U.S. approach of deep underground disposal leads to far less I-129 being released, the researchers found.

The researchers also investigated the effect of environmental regulations and technologies related to I-129 management, to illuminate the tradeoffs associated with different approaches around the world.

“Putting these pieces together to provide a comprehensive view of Iodine-129 is important,” says MIT Assistant Professor Haruko Wainwright, a first author on the paper who holds a joint appointment in the departments of Nuclear Science and Engineering and of Civil and Environmental Engineering. “There are scientists that spend their lives trying to clean up iodine-129 at contaminated sites. These scientists are sometimes shocked to learn some countries are releasing so much iodine-129. This work also provides a life-cycle perspective. We’re not just looking at final disposal and solid waste, but also when and where release is happening. It puts all the pieces together.”

MIT graduate student Kate Whiteaker SM ’24 led many of the analyses with Wainwright. Their co-authors are Hansell Gonzalez-Raymat, Miles Denham, Ian Pegg, Daniel Kaplan, Nikolla Qafoku, David Wilson, Shelly Wilson, and Carol Eddy-Dilek. The study appears today in Nature Sustainability.

Managing waste

Iodine-129 is often a key focus for scientists and engineers as they conduct safety assessments of nuclear waste disposal sites around the world. It has a half-life of 15.7 million years, high environmental mobility, and could potentially cause cancers if ingested. The U.S. sets a strict limit on how much I-129 can be released and how much I-129 can be in drinking water — 5.66 nanograms per liter, the lowest such level of any radionuclides.

“Iodine-129 is very mobile, so it is usually the highest-dose contributor in safety assessments,” Wainwright says.

For the study, the researchers calculated the release of I-129 across three different waste management strategies by combining data from current and former reprocessing sites as well as repository assessment models and simulations.

The authors defined the environmental impact as the release of I-129 into the biosphere that humans could be exposed to, as well as its concentrations in surface water. They measured I-129 release per the total electrical energy generated by a 1-gigawatt power plant over one year, denoted as kg/GWe.y.

Under the U.S. approach of deep underground disposal with barrier systems, assuming the barrier canisters fail at 1,000 years (a conservative estimate), the researchers found 2.14 x 10–8  kg/GWe.y of I-129 would be released between 1,000 and 1 million years from today.

They estimate that 4.51 kg/GWe.y of I-129, or 91 percent of the total, would be released into the biosphere in the scenario where fuel is reprocessed and the effluents are diluted and released. About 3.3 percent of I-129 is captured by gas filters, which are then disposed of in shallow subsurfaces as low-level radioactive waste. A further 5.2 percent remains in the waste stream of the reprocessing plant, which is then disposed of as high-level radioactive waste. 

If the waste is recycled with gas filters to directly capture I-129, 0.05 kg/GWe.y of the I-129 is released, while 94 percent is disposed of in the low-level disposal sites. For shallow disposal, some kind of human disruption and intrusion is assumed to occur after government or institutional control expires (typically 100-1,000 years). That results in a potential release of the disposed amount to the environment after the control period. 

Overall, the current practice of recycling spent nuclear fuel releases the majority of I-129 into the environment today, while the direct disposal of spent fuel releases around 1/100,000,000 that amount over 1 million years. When the gas filters are used to capture I-129, the majority of I-129 goes to shallow underground repositories, which could be accidentally released through human intrusion down the line.

The researchers also quantified the concentration of I-129 in different surface waters near current and former fuel reprocessing facilities, including the English Channel and the North Sea near reprocessing plants in France and U.K. They also analyzed the U.S. Columbia River downstream of a site in Washington state where material for nuclear weapons was produced during the Cold War, and they studied a similar site in South Carolina. The researchers found far higher concentrations of I-129 within the South Carolina site, where the low-level radioactive effluents were released far from major rivers and hence resulted in less dilution in the environment.

“We wanted to quantify the environmental factors and the impact of dilution, which in this case affected concentrations more than discharge amounts,” Wainwright says. “Someone might take our results to say dilution still works: It’s reducing the contaminant concentration and spreading it over a large area. On the other hand, in the U.S., imperfect disposal has led to locally higher surface water concentrations. This provides a cautionary tale that disposal could concentrate contaminants, and should be carefully designed to protect local communities.”

Fuel cycles and policy

Wainwright doesn’t want her findings to dissuade countries from recycling nuclear fuel. She says countries like Japan plan to use increased filtration to capture I-129 when they reprocess spent fuel. Filters with I-129 can be disposed of as low-level waste under U.S. regulations. 

“Since I-129 is an internal carcinogen without strong penetrating radiation, shallow underground disposal would be appropriate in line with other hazardous waste,” Wainwright says. “The history of environmental protection since the 1960s is shifting from waste dumping and release to isolation. But there are still industries that release waste into the air and water. We have seen that they often end up causing issues in our daily life — such as CO2, mercury, PFAS and others — especially when there are many sources or when bioaccumulation happens. The nuclear community has been leading in waste isolation strategies and technologies since the 1950s. These efforts should be further enhanced and accelerated. But at the same time, if someone does not choose nuclear energy because of waste issues, it would encourage other industries with much lower environmental standards.”

The work was supported by MIT’s Climate Fast Forward Faculty Fund and the U.S. Department of Energy.

###

Written by Zach Winn, MIT News

---

Journal

Nature Sustainability

DOI

10.1038/s41893-025-01629-2 

Article Title

"The iodine-129 paradox in nuclear waste management strategies"

Nuclear entering a 'golden age', WNE told

By Warwick Pipe

World Nuclear News, in Paris

Wednesday, 5 November 2025

The figures show that global nuclear electricity generation is set to achieve a record high in 2025, and with more countries turning to nuclear to meet their energy needs, the industry's future looks promising, the World Nuclear Exhibition in Paris has heard.
 

(Image: WNE)

"Two years ago in Dubai in one of these big climate conferences - they are called the COPS, it was the 28th COP - for the first time, everybody around the world ... agreed that nuclear energy should be accelerated, not just tolerated," noted Rafael Mariano Grossi, Director General of the International Atomic Energy Agency. "Accelerated, because we know and we finally accepted the indispensable nature of this through the energy mixes in the world. So from that moment on, and on that occasion, a number of candidates said, well, we should perhaps triple our nuclear percentage. So, of course, big words, big promises.

"From promise to progress, the sector is experiencing a return to realism, as countries expand existing programmes, launch new ones and update regulations to meet future energy needs."

Grossi said that for the first time in the commercial history of nuclear exploitation, the market is demanding it. "The market is pushing for nuclear. It's no longer about states taking decisions top-down and going for an avenue that says nuclear has to be there. And it is obvious where this is happening."

He told delegates to "keep engaged because there are great moments ahead for all nuclear, all over the world."

Grossi's comments were echoed by Fatih Birol, Executive Director of the International Energy Agency, who said at World Nuclear Exhibition (WNE) in 2021 that, looking at the data, he dared to say that nuclear energy may make a comeback. "And today, nuclear is back. Nuclear is back in a very strong way," he declared. "2025, this year, according to our numbers, is the highest amount of electricity generated from nuclear in the world."

Furthermore, he noted, 70 gigawatts of nuclear power plants are under currently construction - "the highest ever in the last three decades". In addition, 40 nuclear newcomer countries have plans to build a nuclear industry. "So all these three things coming together, I think, what I said four years ago, nuclear is going to make comeback, is a reality now.

"In my view, nuclear has a golden opportunity to make this comeback to see a golden age of nuclear power as we have seen in the '70s and '80s. But this is not taken for granted."

Birol added: "The market is there, demand is there, technology is there, and the field of policy is moving in the right direction. Whether or not, in this very fertile and excellent basis, nuclear industry, governments will make sure that we are entering the golden age for nuclear power remains to all of you."

Framatome, TerraPower in advanced fuel breakthrough

Wednesday, 5 November 2025

The metallic 'pucks' of uranium that have been produced at Framatome's nuclear fuel manufacturing facility in the USA are a critical component in the fuel supply chain for TerraPower's Natrium reactor and described as a "milestone" for the commercialisation of advanced reactor fuel.
 

Framatome and TerraPower announced the breakthrough at the World Nuclear Exhibition in Paris (Image: Framatome)

Production of HALEU (high-assay low-enriched uranium) metal is a crucial part of the fuel fabrication process to transform uranium into a metallic feedstock that is used to fabricate fuel for advanced reactors. A metallisation fabrication line has been completed at Framatome's facility in Richland, Washington, and the companies said the process, technologies, and expertise used to produce metal from depleted uranium can be used with uranium at the higher enrichment levels required to power TerraPower's advanced reactor design.

"This milestone underscores the critical progress being made in developing a reliable advanced reactor fuel supply chain and in propelling TerraPower's Natrium technology," Lionel Gaiffe, senior executive vice president of Framatome's Fuel Business Unit, said. "Through this strategic collaboration, we are delivering the next generation of nuclear technology that will define the future of clean energy."

TerraPower's Natrium technology features a 345 MWe sodium-cooled fast reactor with a molten salt-based energy storage system. The company broke ground on the first Natrium project last year at a site in Kemmerer, Wyoming.

Natrium - like many advanced reactors currently under development - will use HALEU fuel, with uranium enriched to contain between 5% and 20% uranium-235. The US Department of Energy established its HALEU Availability Program in 2020 to secure a domestic supply of HALEU for civilian domestic research, development, demonstration, and commercial use, enabling nuclear developers to request HALEU material from DOE sources, including material from the National Nuclear Security Administration. Earlier this year - following Executive Orders to expedite the roll-out of new reactors - the DOE launched a new pilot programme to accelerate the development of advanced nuclear reactors and strengthen domestic supply chains for nuclear fuel.

Successful completion and operation of the metallisation fabrication line demonstrates Framatome's readiness to accept DOE funding as part of the HALEU Availability Program Solicitation and deploy in a Category II facility. (Category II facilities are licensed by the US Nuclear Regulatory Commission to handle "special nuclear material of moderate strategic significance" such as HALEU: the low-enriched uranium used to fuel the USA's current reactor fleet is classed as being of low strategic significance and can be handled in a Category III facility.)

"TerraPower has been committed to supporting the development of a robust, domestic HALEU fuel supply chain," TerraPower President and CEO Chris Levesque said. "The successful production of these metallic uranium pucks proves that we can manufacture the metallisation component of HALEU fuel here in Washington and support our plans to rapidly deploy Natrium plants across the United States."

The Natrium reactor is a TerraPower and GE Vernova Hitachi Nuclear Energy technology.

Industry gets call for action

"Nuclear energy has moved from the margins of energy discourse to the centre of global climate action, national energy security and socio-economic progress," World Nuclear Association Director General Sama Bilbao y León said in a keynote speech later during the opening day.

(Image: WNN)

"Nuclear will be back at COP again, COP30 taking place in Belem, Brazil next week," she added. "World Nuclear Association will be there, representing the industry and providing authoritative information and influencing decision makers. We hope for more countries, and key stakeholders to join our growing coalition of the ambitious. But declarations alone are not enough. We - the nuclear industry - must now deliver." 

She said the world will need at least 1000 GWe of new nuclear generating capacity in the next 25 years. "Over the past 25 years we added 100 GWe, so we need to do much more than triple our delivery capacity. The groundwork is being laid, but the path ahead requires unity, urgency, and unwavering commitment."

Bilbao y León declared: "To succeed, we must turn political goodwill into pragmatic policies. That means streamlining licensing, securing affordable financing, expanding our supply chains, and investing in human capital. Governments will set the frameworks - but it is us, the industry, who must build and operate this future. Let me be clear: a successful project anywhere is a success everywhere. Every reactor that comes online, every innovation that proves viable, every community that embraces nuclear - these are victories for all of us. They build confidence, attract investment, and inspire replication."

She called for the nuclear industry to "unite around shared goals ... Share best practices, support each other's projects, and speak with one voice when it comes to the value of nuclear energy. The world is watching. The nuclear industry must be ready."

Kansai begins surveys of Mihama site for new reactor

Wednesday, 5 November 2025

Japanese utility Kansai Electric Power Company is beginning surveys of the Mihama nuclear power plant site in Fukui Prefecture to determine if a new reactor could be built there as a replacement for unit 1, which was declared permanently shut down in 2015.
 

The Mihama plant (Image: Nuclear Regulation Authority)

In a statement on Wednesday the company said: "As preparations for the on-site investigation are complete, we began transporting materials and equipment today and have begun the investigation. Further preliminary investigations, including drilling surveys and surface reconnaissance, are scheduled to be completed by around March 2027.

"We will prioritise safety during this investigation, and will continue to work hard to ensure the safe and stable operation of our nuclear power plants. We will continue to promote our nuclear power generation business with the understanding of local residents and others."

The projected timeline is for the detailed survey to take place from April 2027 to 2030.

According to a Jiji Press report the survey "will examine the geological and topographical conditions of two areas inside and outside the existing plant".

Kansai originally announced in November 2010 its intention to begin a voluntary survey at the Mihama site for the construction of a new reactor to replace unit 1 there. However, the survey has been suspended since the accident at the Fukushima Daiichi plant in March 2011.

According to a Reuters report in July, Kansai is considering deploying the SRZ-1200 advanced light water reactor being developed by Mitsubishi Heavy Industries (MHI).

MHI launched the SRZ-1200 design, which is being developed in collaboration with four Japanese utilities, in 2022. The 1200 MWe reactor is designed to meet the country's enhanced regulatory safety standards.

While both units 1 and 2 at the Mihama plant have been shut down, unit 3 of the plant is among the Japanese reactors that have resumed operation, having been restarted in June 2021.

The last nuclear power reactor to be constructed in Japan was unit 3 of Hokkaido Electric Power Company's Tomari plant, which began operation in 2009.

Tractebel and Hexana launch SMR cogeneration task force

Wednesday, 5 November 2025

The two companies have signed a memorandum of understanding aimed at promoting nuclear-powered cogeneration "as a key solution for industrial decarbonisation, energy system resilience, and efficiency across Europe".
 

The MoU was signed at World Nuclear Exhibition (Image: Tractebel)

Belgium-headquarted Tractebel and Hexana, which was spun out of the French Alternative Energies and Atomic Energy Commission, are aiming to bring together stakeholders from the nuclear, industrial and cogeneration sectors in a new small modular reactor and advanced modular reactor Cogeneration Task Force.

Hexana aims to develop a small modular reactor featuring a sodium-cooled fast neutron reactor, integrated with a high temperature storage device. A plant would comprise two of these reactors (400 MWt each) supplying a heat storage device. An adjoining conversion system will allow it to produce electricity on demand and in a flexible manner to compete with gas-fired power plants, but also to supply heat directly to nearby energy-intensive industries.

Cogeneration refers to producing both electricity and heat and is seen as a way to be able to decarbonise, in particular, certain heavy industries. The new task force will be within COGEN Europe, which is the European Association for the Promotion of Cogeneration.

Bernard Marié, Head of Flex Power, Renewable, Industry & SMR at Tractebel, said: "Decarbonising industry remains one of Europe's greatest challenges, with hard-to-abate sectors like cement, steel, and chemicals responsible for over 60% of EU industrial CO2 emissions. Under the umbrella of COGEN Europe, the Task Force is a strategic step to unlock the potential of nuclear cogeneration and help shape a low-carbon industrial future for Europe. We invite all stakeholders to join us in this effort."

Sylvain Nizou, Hexana CEO, said: "Nuclear cogeneration represents a unique opportunity to combine energy efficiency and low-carbon innovation to replace fossil fuels in industrial clusters. By joining forces, we can make nuclear cogeneration a visible, credible, and supported pathway for industrial decarbonisation in Europe."

Hexana and Tractebel said that their shared vision with the MoU was "ensuring that nuclear cogeneration gains greater recognition within European strategies and financial frameworks supporting the clean energy transition".

Latvia’s nuclear emergency preparedness reviewed by IAEA

Wednesday, 5 November 2025

An International Atomic Energy Agency mission has praised Latvia’s “strong commitment to enhancing nuclear and radiological emergency preparedness" and suggested measures to further strengthen it, including by implementing a national coordinating mechanism in all emergency response organisations.
 

(Image: State Environmental Service)

The 10-day, six-person, Emergency Preparedness Review Service mission was requested by the Latvian government and hosted by the Radiation Safety Centre of the State Environmental Service.

Genaro Rodrigo Salinas Mariaca, Senior Specialist on Emergency Preparedness and Response at the Federal Authority for Nuclear Regulation in the United Arab Emirates, led the team which also included experts from Bulgaria, Indonesia, Portugal, Finland and the IAEA.

He said: "The outcomes of this mission highlight both well-established practices and valuable opportunities for further strengthening integration, coordination and resilience."

Examples of strengths identified included: the continuous proactive approach and strong determination of the radiation safety centre in leading preparedness and response initiatives for nuclear and radiological emergencies; the government's efforts to establish reliable communication channels to disseminate information and instructions to potentially affected populations; and on-going initiatives to build public trust through effective crisis communication as a way to strengthen the overall national emergency response framework.

Suggestions made included: to align national regulations and emergency frameworks with relevant international safety standards; to implement a national coordinating mechanism in all emergency response organisations; to integrate the Crisis Management Centre into the national framework; to conduct hazard assessments in line with relevant international safety standards; define guidance values for emergency workers and helpers, including provisions to register and integrate non-designated emergency workers and helpers into emergency response arrangements; and establish arrangements for environmental and food monitoring during emergencies.

It also stressed the importance of organisations having sufficient qualified personnel to carry out their emergency responsibilities.

Kaspars Melnis, Latvia's Minister of Climate and Energy, said: "This review has enabled us to benchmark our systems against international best practices, identify areas of strength and pinpoint opportunities for improvement. We are committed to translating the mission’s recommendations into concrete measures to further enhance our preparedness and response capabilities, ensure public confidence, and remain aligned with international safety standards. Latvia values its partnership with the IAEA and looks forward to deepening cooperation in the years ahead."

The Radiation Safety Centre of the State Environmental Service said that before the mission it had already prepared a new draft Cabinet of Ministers regulation to include the requirements of international safety standards, replacing those from 2003. "Based on the recommendations of the experts, the draft regulation will be improved" it said, and would, in cooperation with other institutions, develop an action plan for the implementation of the recommendations made as a result of the mission.

Latvia does not currently have any nuclear power reactors; its research reactor closed in 1998 and is in the early stages of decommissioning. It uses radiation sources in medical, scientific and industrial applications and has a disposal and storage site for low and intermediate level radioactives waste 30 kilometres from the country’s capital, Riga.