Contributions of the radonorm project to European and international radiation protection research

RadoNorm has come a long way since its inception, in addressing and managing risks for radon and NORM. The output of the project has been substantial in generating new findings and developing novel methodologies and tools. At the same time, the project has been translating its results into recommendations, which have been published as deliverables and scientific publications, and communicated to various stakeholders through its annual meetings, monthly webinars and the most recent RadoNorm Showcase Meeting held in Brussels. This review aims to produce a comprehensive summary of RadoNorm results and recommendations until this point (June 2025) as well as the recent discussions at the RadoNorm Showcase Meeting in March 2025, where the results were presented to a variety of stakeholders including the radiation research platforms. The results are presented under the themes of "health effects and risks", "exposure and mitigation" and "risk communication and societal aspects". RadoNorm has performed a comprehensive assessment of what has been achieved and what future questions have arisen from the latest results of the project, which are also elaborated upon herein and addressed as challenges for the European radiation research platforms to assimilate into their research portfolios.