Primary Radiation Damage Cross Sections

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Project Type

Coordinated Research Project

Project Code




Approved Date



3 - Active - Ongoing

Start Date


Expected End Date


Completed Date


Participating Countries

Republic of Korea
Russian Federation
United Kingdom of Great Britain and Northern Ireland
United States of America


The radiation damage in the materials is  a key parameter that eventually defines the life expectancy and safety operation of the nuclear facilities. The time evolution and final appearance of material changes depend on the type, intensity and energy spectra of incident radiation as well as on the materials properties and ambient environment. Although this process is not yet completely understood, it has been established that some material property changes are sensitive to the results of nuclear collisions (atom displacement and gas production), while others are more sensitive to the effects of ionization.  For the group of practically important materials with crystalline structure, such as metals, ceramics and some alloys, the atom displacement cross section was found to be a reference parameter suitable for characterization and comparison of the radiation damage induced by neutrons and charged particles.  The so-called NRT-dpa standardproposed by Norget, Torrens and Robinson for evaluation of the number of displaced atoms  has been universally used since 1975. Although the usefulness of the NRT-dpa for correlating many radiation damage phenomena was recognized, its limitations were also demonstrated with indications that other parameters could be used to better correlate certain kinds of data.  The development of specific damage models is best done within the materials community, based on information obtained from nuclear data researchers. For a given irradiation environment, these data need to include the primary knock-on atom (PKA) spectrum, nuclear transmutation rates (particularly gas production), and partitioning of the PKA energy into nuclear and electronic stopping effects. This CRP engages participants from both the nuclear data and materials research communities and will determine the best possible parameter (or a few parameters) for correlating damage from irradiation facilities with very different particle types and energy spectra, including fission and fusion reactors, charged particle accelerators, and spallation irradiation facilities. The essential progress in the course of CRP is expected for crystalline materials (such as fuel UO2, structural metals, SiC), for which the upgraded cross sections for the primary damage (primary radiation defects and gas production) will be produced.


To find ways to overcome the drawbacks, limitations of the NRT-dpa relying on recent/modern developments in primary radiation damage simulations. For this, engage in this project experts from the nuclear data and material research communities together to:revisit the NRT-dpa protocols, improve recoil and emitted particles spectra treatments, account for uncertainties, propose new metrics, extend the energy range;elaborate upgraded primary radiation defect metrics to better capture the annealing, evolution of defects in the recoil cascades on the basis of MD, BCA and other models;demonstrate better metrics to correlate experimental (ions based) to model parameters (neutron based) for microstructural material damage;review, enhance gas production from evaluated nuclear data files and make recommendations.

Specific objectives

- Encourages, entices the nuclear data/processing and materials research communities to more efficiently work together, develop better metrics and models. - Engage the true multi-scale (atom/isotope-molecule/element-alloy/material) aspects of characterising materials properties evolution under particles irradiation. - Provide, elaborate and engineer more robust methodologies able to cover all experimental and modelling aspects of study of materials under ions and neutron irradiations. Most experimental information are based on ions, while the next generation devices will endure high energy neutrons. - Develop the physics and metrics to bridge the gaps.

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