ASN Report 2018

This oversight is carried out during inspections (specifically on the topic of radiation protection, one to two times per year and per site, during reactor outages, following incidents, or occasionally in the EDF head office departments and engineering centres), and during the review of files concerning occupational radiation protection (significant events, design, maintenance or modification files, EDF documents implementing the regulations, etc.) with the support of IRSN when necessary. Periodic meetings are held with EDF as part of the technical dialogue with the licensee. They enable ASN to check the progress of technical or organisational projects being run to improve radiation protection. • Significant contamination events Two significant contamination events were notified in 2018 in the NPPs operated by EDF. These events, which led to exposure greater than one quarter the regulation limit per square centimetre of skin, were rated level 1 on the INES scale. They concern: ∙ ∙ contamination of the skin of the neck of a worker assigned to maintenance work in the Cruas-MeysseNPP; ∙ ∙ contamination of the skin under the beard of a worker assigned to maintenance work in the Tricastin NPP. 2.7.2  –  Evaluation of personnel radiation protection The collective dose on all the reactors increased in 2018 by comparison with 2017 (Graph 5), as did the average dose received by workers for one hour of work in a controlled zone. However, these values remain lower than those recorded in 2015 and 2016. The doses received by the workers are broken down as shown below in Graphs 5 and 6. Graph 6 shows the breakdown of the workers in terms of whole body external dosimetry. It can be seen that the dosimetry for 77% of the exposed workers is less than 1 mSv for the year 2018, which corresponds to the annual regulation limit for the public. The annual regulation limit for whole body external dosimetry (20 mSv) was exceeded on no occasion in 2018. Graph 5 shows the trend in the collective dose received by NPP workers over the past ten years. Despite a slight increase in the collective dose received in 2018 by comparison with 2017, this Graph shows a trend towards stabilisation of the average collective dose per reactor over the past few years. Graph 7 shows the trend in whole body average individual dosimetry according to the worker categories in NPPs. The most exposed worker categories in 2018 are personnel in charge of thermal insulation, monitoring, inspection and welding and mechanical work. ASN considers that in 2018 the way the NPPs deal with radiation protection varies, notably with regard to control of radiological cleanness within the facilities and the steps taken to prevent the risk of contamination. In the light of these findings, ASN carries out tightened checks on the implementation of the action plans required to correct these situations on the reactors concerned. ASN considers that, on the whole, the radiation protection situation of the NPPs in 2018 should be improved on the following points: ∙ ∙ a lack of radiation protection culture on the part of certain outside contractors was fond by the ASN inspectors on several sites. Steps are required to reinforce monitoring and to develop exchanges between the various EDF entities and outside contractors concerning the protective measures to be taken; ∙ ∙ control of industrial radiography worksites remains fragile. ASN in particular identifies several events concerning shortcomings in signage or involving the presence of workers in the exclusion zones. Progress is required in the preparation of the worksites, more specifically multiple contractor activities, the optimisation of signage and the quality of the installation walkdowns carried out when preparing these worksites; ∙ ∙ the dosimetry optimisation approach must be reinforced, more particularly the exhaustiveness of the risk assessments for the work and their reassessment following unforeseen events; ∙ ∙ greater rigorousness is required in the administrative management of sources; Evolution of mean individual dose according to categories of workers in NPPs 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Risk Prevention Welding Auxiliaries Mechanical Expert appraisal Tests Electricity Checks - Inspections Thermal insulation Administrative 2015 2016 2017 2018 Source: EDF Graph 7 ASN report on the state of nuclear safety and radiation protection in France in 2018  303 10 – EDF NUCLEAR POWER PLANTS 10