Led by IRSN, the international CABRI (CIP) program, under the supervision of the OECD Nuclear Energy Agency, studies the behavior of nuclear fuel rods in pressurized water reactors during an accidental power excursion transient.

This test, carried out by IRSN and CEA teams on April 24, 2023, and named CIP3-3, was the fifth test in the CIP program conducted in the CABRI facility, and the third in a "water loop" configuration, representative of the thermal-hydraulic conditions of a pressurized water reactor (PWR). The fuel rod consisted of UO2 fuel and an Optimized ZIRLO cladding: a first for the CABRI facility. The simulation was carried out using a neutron pulse lasting around ten milliseconds and with a power of 13 GigaWatt.

The purpose was to study the behavior of this type of cladding, and to investigate the reaching of the boiling crisis, in an accident situation such as reactivity injection.

The rod will now be analyzed by IRSN at a dedicated station (IRIS) in the CABRI reactor hall, before being transferred at the end of the year to CEA's active fuel examination laboratory (LECA), where it will first undergo non-destructive and then destructive analysis. This, combined with the on-line measurements acquired during the pulse, will enable the most complete possible interpretation of the test.

The Sustainable Nuclear Energy Technology Platform (SNETP) association, of which IRSN is a member, organized a "Coordinators Hub Day" seminar bringing together coordinators of projects involved in EU-funded consortia under EURATOM and Commission representatives. Indeed, SNETP works in favour of innovation in the nuclear field and in particular in safety, and one of its missions is to be a facilitator in the development of actions, and to be a real catalyst of the European ecosystem in its field.

The event was held on March 14, 2023 at the Maison Irène et Frédéric Joliot-Curie (MIFJC) in Brussels, of which IRSN is a member. The MIFJC helps strengthen the presence and participation of French science in the European Commission, the European Parliament, and operators active in the political, economic and social sphere in Brussels.

This day of exchanges was the occasion for the coordinators to confront their expectations to the reality and to bring solutions to overcome the difficulties encountered (in terms of management, administration). They were also able to have privileged exchanges with the project leaders of the European Commission concerned, in order to understand the practical needs of the research community and to develop common solutions.

SNETP also presented potential solutions that could help all types of projects and promote synergies with all relevant tools in the fields of training (the ENEN association participated in the event), communication and the efficient use of National Contact Points (NCPs) in particular.

On the eve of the World Cancer Day, IRSN organised in partnership with CEA, Inserm and CNRS [1], a conference dedicated to the contribution of research on the use of ionising radiation to the fight against cancer.

This venue organised under the auspices of Marie-France Bellin and Jean-Christophe Niel, respectively chair of the board and director general at IRSN, took place at Maison Irène et Frédéric Joliot Curie, the Brussels base of several major French research institutions. Structured around three headlines – French strategy and roadmap, state-of-the-art research, and European and international actions – the presentations and debates among scientists, academics and representatives from government and international organisations highlighted the challenges, progress made, and future prospects of scientific research in medical applications such as imaging, nuclear medicine or radiotherapy where radiation technologies are used for diagnosis and/or therapy.

Acknowledging improvements achieved in cancer diagnosis and treatment

In France, like in many European countries, the use of ionising radiation in cancer diagnosis and treatment keeps growing with over 55% of patients being treated by radiotherapy. This constant increase raises many questions – e.g. on the benefit/risk balance of innovative radiation technologies (new radiopharmaceuticals, Proton-therapy or Flash-therapy), the development of combined treatment to cure radioresistant tumours or the adverse effects and the patient quality of life. These questions require in turn further research aimed at developing ever more efficient and less affecting therapeutic strategies. In this regard, the participants in the conference acknowledged the progress made over the past years in terms of improved benefit/risk balance, increased life expectancy and higher quality of life through reduced side effects, just to name a few.

Shaping the future of treatments

The presentations and debates were an opportunity to address major benefits expected from research projects from different perspectives:

• Enhanced therapy efficiency through innovative irradiation modalities such as hadrontherapy, spatial fractionation, flash therapy, drug-assisted targeting (using e.g. nanoparticles);
• The further improvement of the benefit/risk balance of imaging and treatments with, in particular, the contribution of artificial intelligence (AI) and machine learning to obtaining high-quality imaging with lower dose intake;
• The prevention of adverse effects from treatments, the reduction of the toxic effects of radiotherapy on healthy tissues, or the occurrence of immunosuppressive and/or long-term effects, thanks to AI-guided dose delivery;
• The benefit from new approaches in nuclear medicine such as theranostics (the combined use of one radionuclide to diagnose and a second one to treat the tumour, main and any metastatic), or the combined use of radiotherapy with other therapies (immunotherapy, hormonotherapy …);
• The trend towards personalised medicine based on patient-centric, cross-disciplinary approaches taking into account individual patient parameters and personalised dosimetry;
• The development of ultra-precision radio-immunotherapy using imaging-biomarkers for efficient treatment of oligometastatic patients…

Addressing challenges

Most of the prospects mentioned above require disruptive approaches based notably on the development of multidisciplinary and multi-scale approaches which entail the integration of teams working in various fields to deal with the diversity in tumour and non-tumour tissue response e.g. physicochemical, molecular, and physiological phenomena. Other challenges associated with the rapid evolution in cancer diagnosis and treatment techniques pertain for instance to the quality assurance in radiotherapy, the secured production of radioisotopes, the funding of state-of-the-art research drawing upon ever more sophisticated equipment or the equal access to radiological medicine, as well as the safety of caregivers and patients, calling for the involvement of patient associations in future developments.

Tackling such challenges is key to the success of research activities carried out as part of strategic plans at national, European and international levels, such as the French 10-year strategy against cancer, the Europe's Beating Cancer Plan or the IAEA's Rays of Hope initiative. It is for instance the sense of major research projects conducted as part of European framework programmes for research and innovation (H2020/EURATOM and Horizon Europe), such as Rocc-N-Roll, an integrated and coordinated European approach for innovation and research in the field of medical applications using ionising radiation, and PIANOFORTE, an IRSN-coordinated partnership aimed to contribute improving the protection of the public, workers, patients against environmental, occupational and medical exposure to ionising radiation. This partnership also intends to foster the management of research programmes at scientific community level through open research calls.

Note:

1. Alternative Energies and Atomic Energy Commission (CEA), National Institute of Health and Medical Research (Inserm) and National Centre for Scientific Research (CNRS).

IRSN contributes, at national and European level, to the fight against cancer

Technological advances and changes in protocols developments in the fields of imaging, radiotherapy and nuclear medicine are very rapid. Regularly assessing the risks associated with these developments with regard to the therapeutic benefits is at the heart of the missions of the Institute for Radiation Protection and Nuclear Safety. The optimization of practices using ionizing radiation is also a constant objective of the Institute.

To fulfil its missions in these fields, IRSN carries out expert assessments for health authorities and, more generally, for public authorities, and also monitors the exposure of patients, medical personnel and the public.

In support of these assessments and monitoring activities, and in order to be at the forefront of knowledge, the Institute conducts research programs in collaboration with hospital teams and national, European and international partners.

In this sense, since June 2022, IRSN has been coordinating the European PIANOFORTE partnership for research in radiation protection. Part of the work of PIANOFORTE is based on the European priority policy for the fight against cancer, and relies on different European initiatives or projects such as SAMIRA (Strategic Agenda for Medical Ionising Radiation Applications) or Rocc-n-Roll aiming at defining research priorities for medical radiation protection.

At the national level, IRSN's actions are also part of the ten-year cancer control strategy led by INCa. These research activities are focused on optimizing practices, such as the development of modern approaches to dose calculation. The ultimate goal is to personalize treatment and limit side effects in order to improve patients' quality of life after treatment.  To contribute to this objective, IRSN has entered into partnerships with hospitals such as Gustave Roussy (project PiRaTT) and AP-HP hospitals (project Epibrainrad and project Radioaide), as well as with academic institutions.

Download the Press release

A delegation from the National University of Singapore (NUS)/Singapore Nuclear Research and Safety Initiative (SNRSI) led by Professor Pao Chuen LUI, Chairman of SNRSI and SNRSI Director Keng Yeow CHUNG and from the Energy Market Authority led by Director Darryl Kah Inn CHAN visited IRSN's safety and radiation protection research facilities at Cadarache on September 19 and 20, 2022.

The facilities visited were the following: 

• AMANDE​,
• MIRCOM, 
• CABRI model, 
• THEMA, 
• CHROMIA, 
• MAESTRO, 
• ODE, 
• GALAX​IE.

The dele​​gation continued this visit to IRSN Headquarters at Fontenay-aux-Roses on September 23, with a presentation of the research and expertise conducted on atmospheric dispersion models, followed by a presentation of crisis management and the technical Crisis Center.

A final debriefing meeting led by the Director General of IRSN Jean-Christophe NIEL concluded this visit.

The European Commission (EC) has just published the results of its call for projects of the Horizon 2020 programme for 2018-2019. IRSN is participating in eight of the thirteen new European projects which will be launched during the year.

The recent success of IRSN's H2020 call for projects is part of the IRSN Contract of operational objectives and performance (COP) renewed with the French State until 2023. One of the challenges of this contract is to develop national, European and international partnership initiatives to deploy the scientific strategy and conduct high-quality research to meet the challenges of expertise. It confirms the IRSN position as a major player in research in the field of nuclear safety, radiation protection and environment. This result reflects IRSN dynamism in the proposals made and its contribution to collective actions for research at European level. 

Jean-Christophe Niel, Director general of IRSN, points out that "40% of IRSN budget is dedicated to research to contribute to the improvement of knowledge on nuclear safety and radiation protection and develop the expertise of IRSN with the best scientific knowledge". 

For the first time, IRSN was represented in all technical fields. Some of the key research themes selected include:

In the field of nuclear safety: two projects concerning Generation II and III reactors, R2CA (Reduction of Radiological Consequence in design based Assessment), on the radiological consequences of design accidents and their management strategy led by IRSN, and MUSA (Management and Uncertainties in Severe Accidents), on the improvement of severe accident simulation tools, in which IRSN will be in charge of coordinating the Work Package on the study of innovative mitigation means for accidents in storage pool.

In the field of safety of Generation IV reactors: the SAMOSAFER project (Severe Accident Modeling and Safety Assessment for Fluid Fuel Energy Reactors), led by the University of Delft, with IRSN participation.

In the field of safety of light water modular reactors, IRSN takes part in all technical work packages of the ELSMOR project (towards European Licensing of Small MOdular Reactors), led by the Technical Research Center of Finland (VTT).

It should be noted that the Institute will join the continuation of a project on nuclear data for modeling applications: SANDA follow-up (Supplying Accurate Nuclear Data for energy and non-energy Applications), piloted by CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas, Spain). IRSN is also participating in the SHARE project (StakeHolder-based Analysis of REsearch for decommissioning) on the development of a roadmap for research on the decommissioning of facilities.

In the field of nuclear waste management: the EURAD project (EURopean joint programming on RAdioactive Waste Management and Disposal) on all the technical aspects of deep geological disposal of waste, led by ANDRA.

Finally, in the field of radiation protection, the HARMONIC project (Health effect of cArdiac fluoRoscopy and MOderN radiotherapy In pediatriCs), coordinated by ISGlobal Spain, focuses on the health effects of fluoroscopy (or radioscopy) and new approaches to pediatric cardiac radiotherapy.

More information: IRSN research programs

Result of the French-Japanese research project Shinrai, the report "The 3/11 accident and its social consequences - Case studies in Fukushima prefecture" analyses post accidental policy in Fukushima prefecture, particularly the questions linked to return or non-return to evacuated towns and villages. The report also compares the concrete experience of the inhabitants and the decision-makers with a number of principles that underlies international post accidental policy and recommendations.​

Download IRSN Report 2019/00178: Shinrai research Project: The 3/11 accident and its social consequences. Case studies from Fukushima prefecture

Eight years after the Fukushima Daiichi nuclear accident in Japan, IRSN publishes a report on its social consequences. This research is based on an intensive field work carried out by researchers with inhabitants of the Fukushima prefecture. The Institute investigates this topic within the framework of the Shinrai project​, a French-Japanese research program coordinated by IRSN with the participation of Sciences Po Paris and To​kyo Tech.

The framework of this research is inscribed in the field of disaster studies, with a multidisciplinary approach (anthropology, political sciences, sociology) in order to analyze the trust of Japanese citizens towards the government in charge of dealing with the crisis. Between 2014 and 2017, researchers from IRSN and Sciences Po completed 118 interviews during 8 missions of 2 to 3 weeks:​

• ​​​Inhabitants of the Watari quarter in Fukushima city (60 km from t​he crippled Fukushima Daiichi nuclear power plant), the town of Naraha and the village of Kawauchi, who were allowed to return or not to their hometown after the lifting of evacuation orders (EOs) by the Japanese government (see interactive map below),
• Government and local representatives to better understand the policy of lifting of EOs after decontamination,
• ​Non-Profit Organizations (NPOs) or independent experts, who played an important role in informing and supporting the population.

Despite decontamination and the lifting of EOs, the rate of returnees is relatively low. The fieldwork identified six broad categories of inhabitants in relation to their decision to “whether return or not” after the lifting of EOs. This categorization shows the diversity of situations, depending on age, family status - for example, family with children -, commitment to the post accidental policies, confidence in the assessment of radiological situation by government experts.

​​The research highlights the role of local elected representatives, in this case the mayors, by showing how they sought to meet both government requirements and the wishes of their constituents. It also addresses the ethical dilemmas that politicians, authorities and government experts have faced: is it legitimate to reassure the population at all costs? How to decide when the interests of the inhabitants question the notion of "community" conceptualized as a homogeneous set of persons? 

The report concludes by comparing co​ncrete situation in Fukushima with a number of principles that underlies international post accidental policy and recommendations. This report identified three ways to fuel the reflections in the French and international bodies in charge of managing the post accidental phase:

• ​The attachment of the inhabitants to their hometown, observed after the Chernobyl accident, was not verified in Fukushima. However, this is an assumption underlying post accidental policy, as noted in Publication 111 of ICRP, the international body responsible for radioprotection recommendations. The decision of the Japanese government to "reconquer" the territories by entrusting their decontamination to private companies is appreciated by those who wish to return, but denounced by those who would have preferred that the money be invested otherwise (allowing a final relocation for example).
• The commensurability of radiological risk with other risks (tobacco, alcohol or natural risks specific to Japan). This rationale is recurrent in the discourses of radiological protection but shows some limitations in the aftermath of the Fukushima nuclear accident. While this principle is acceptable to some inhabitants, it is radically dismissed by others, who cannot put in balance the health of their children or accept this​ “balanced” approach.
• The designation of zones as a tool for radiation protection of populations. This pillar of Japanese post accidental policy was based on the international regulation and recommendation framework established by ICRP and IAEA. However, zoning choices have been questioned, including their definition based on the level of radioactivity measured or estimated for the future.​​​

Download IRSN Report 2019/00178: Shinrai research Project: The 3/11 accident and its social consequences. Case studies from Fukushima prefecture

​About the Shinrai project

​Shinrai ("confidence", in Japanese) is a French-Japanese research project started in 2014. Led by IRSN with the participation of Sciences Po Paris and Tokyo Tech, it aims to investigate the decision making methods used by authorities following the accident and their impact on the population.

The project studies the role of public authorities, their trustworthiness (ability to meet the confidence of citizens) and their accountability (ability to account to their own decisions), including in a context when scientific data alone do not allow to proceed and legitimize decisions.

Along with their NEA peers, a number of IRSN experts will contribute actively to three projects to prepare for the decommissioning of the damaged Fukushima Daiichi reactors: one project to prepare the recovery and analysis of fuel debris (PreADES PreADES [http://www.oecd-nea.org/jointproj/preades.html]), another to examine the state of the damaged reactors (ARC-F) in more detail, and another to thermodynamically characterize the fuel debris and fission products (TCOFF).

IRSN intends to share its expertise internationally: by contributing to the synthesis of knowledge acquired from the Fukushima Daiichi accident, by contributing its expertise to the analysis of debris samples from the damaged reactors, by upgrading its thermodynamic databases (NUCLEA, MEPHISTA).

IRSN expects that its participation in these three projects will help to strengthen its expertise capacity on severe accidents: it will gain a better understanding of the limits of the various tools and methods it has developed through its studies and research, by applying them to the reality of an accident that has been thoroughly analyzed.

On 16 April 2018, IRSN and the CEA successfully completed a first test simulating an accident situation in the Cabri reactor at Cadarache as part of an experimental programme. This experiment was conducted on a new pressurised water loop and is the first step in the CIP international research programme to improve reactor safety.

Purpose of the test

The Cabri International Programme (CIP) seeks to improve knowledge of fuel behaviour in pressurised water reactors (PWR) during an accident involving a sudden increase of power in the reactor. The first test under the programme was conducted on 16 April 2018, on the renovated CABRI reactor, equipped with an experimental pressurised water loop [1]. This loop will be used to analyse fuel behaviour in a thermal-hydraulic configuration, representative of a PWR. The instrumentation installed by IRSN in the CABRI reactor can take vital measurements for interpreting tests. The Hodoscope is the only equipment of its kind in the world to provide real-time measurements of the power along the rod tested, its elongation and any potential fuel relocation.

The purpose of the first test is to ensure that the new loop works properly, study boiling following heat transfer from the fuel rod to the water, and the behaviour of fuel in the event of sudden and mass heat injection.

According to Jean-Christophe Niel, Director General of IRSN, “the next step in the programme hinges on testing the irradiated fuel rods in an environment as close as possible to that of a pressurised water reactor core. These conditions have never before been created in this kind of experiment. The aim is to obtain the knowledge required to assess the safety of PWR reactors.” The test will study heat exchange between the coolant and rod cladding, along with the thermal interaction between the ejected fuel fragments and water in the event of cladding rupture.

IRSN research on fuel behaviour in accident situations

IRSN research focuses on fuel behaviour under various accident situations that could affect pressurised water reactors:

• uncontrolled development of the nuclear reaction resulting from ejection of a control rod assembly formed of absorbent rods that help control the nuclear reaction;
• loss of coolant accident (LOCA) caused by rupture of the reactor coolant pressure boundary;
• dewatering of a spent fuel pool, in particular subsequent to feedback from the Fukushima-Daiichi accident.

These research projects are essential for developing the expertise of IRSN teams.

Jean-Christophe Niel underlines that “these research projects have objectives shared by the international community and need to promote partnerships in France and abroad with IRSN counterpart institutions, in particular the ETSON network [2], and with research bodies such as the CEA, with whom we are working hard to ensure the success of the Cabri International Programme (CIP).”

In addition to the experimental programmes conducted in the CABRI reactor, IRSN research draws on a large database of international experiments, comprising results from reactor tests (NSSR in Japan, BIGR in Russia, etc.) and analytical tests on cladding behaviour and heat transfers. IRSN is also participating in a number of international research programmes, in particular an OECD project in Halden, Norway, and another in Studsvik, Sweden. It is also carrying out projects funded by the French National Research Agency (ANR) in a post-Fukushima context, on fuel behaviour in a spent fuel tank in the event of dewatering, and on the coolant of a fuel assembly deformed during a LOCA. In addition to large-scale tests under representative conditions, earlier work is carried out with academics to develop and approve the models later integrated into simulation software used for safety studies.

Notes:

1. Two initial tests were conducted in a “sodium” loop before renovation of the reactor and the development of the pressurised water loop. It will be possible to compare these results with results from the tests conducted in the pressurised water loop.
2. The main role of technical safety organisations (TSO) is to scientifically assess the safety of nuclear facilities and the radiation risks. Within the international network, Etson, they now also work on research, discussions concerning future choices, training and even communication with society on nuclear and radiation risks.

CEA CABRI research reactor at Cadarach

The CEA operates the CABRI research reactor on behalf of IRSN. It is its experimental facility to study the behaviour of nuclear fuel in the event of an accidental power increase, located at the CEA Cadarache research centre in the South of France (Bouches-du-Rhône).

The reactor was built in 1962 and has been adapted since its construction for the purposes of safety studies on French nuclear facilities, from fast neutron reactors to recent pressurised water reactors.

It has therefore undergone a major renovation programme (civil engineering, fire protection, etc.) in order to comply with current safety standards and install an experimental pressurised water loop. As acknowledged by François Gauché, Director of Nuclear Energy at the CEA, “this renovation programme required significant resources from the CEA and IRSN over a long period of time. This first pressurised water loop test is a token of our collective success.”

One specific property of the CABRI reactor is the rod system in its core, which uses an ultra-rapid depressurisation phenomenon to change the reactor power by a factor of around 200,000, from 0.1 MW to 20,000 MW in just a few milliseconds, for a very short duration of 10 to 100 ms.

About the CEA
The CEA is a public research body that works in four fields: defence and security, nuclear and renewable energies, technological research for industry and fundamental research. Drawing on its widely acknowledged expertise, the CEA actively participates in collaborative projects with a large number of academic and industrial partners. With its 16,000 researchers and staff, it is a major player in the European Research Area and its international presence is constantly growing. www.cea.fr

About IRSN
IRSN is a public body with industrial and commercial activities (EPIC). Its missions are now defined by French Act no. 2015-992 of 17 August 2015 on the energy transition for green growth (TECV). It is the public expert in France on nuclear and radiation risks. IRSN contributes to public policy on nuclear safety and human and environmental protection against ionising radiation. It is a research and assessment body, working with all players affected by these policies, while retaining its independent position. IRSN operates under the joint authority of the Ministries of the Environment, Research, Energy, Health and Defence.