 INES 2 |
Dose to a worker exceeding a statutory annual dose limit |
On 11 March, an employee of EdF in the Service for Safety and Radiation Protection received an abnormal dose of radioactivity while working in a controlled "red" area of reactor no. 1 of the Tricastin nuclear power plant that has been shut down for maintenance.
Under the supervision of the Office for Protection against Ionizing Radiation (OPRI), the employee received appropriate medical follow-up and biological examinations to confirm the dose actually received.
This dose was initially estimated to be 80 mSv on the basis of electronic dosimeter carried by the employee. The dose as shown on the radiological film, which has just been developed, is evaluated at 340 mSv. The difference between these results is being investigated.
The regulatory threshold is currently established at 50 mSv per year and will soon be brought down to 20 mSv per year.
"Red" controlled areas are areas with the highest level of radioactivity and where access is strictly regulated.
The operation carried out by the employee involved removing maintenance tools used during the shutdown from the "red" area beneath the vessel of reactor no. 1
The inspection that was immediately carried out by the Nuclear Safety Authority concluded that this operation was carried out without the plant management's authorization, which is however required for entry into a "red" area, and without prior analysis of the associated individual and collective dosimetry as provided for by the regulations.
It was also noted that three employees of the Service for Safety and Radiation Protection, including the employee who received the radioactivity dose, did not comply with the radiation protection regulations.
An official report was therefore drawn up by the work inspector on the failure to comply with the provisions of the radiation protection code of work.
Since an employee of EdF exceeded the regulatory limit on exposure to ionizing radiation, the Nuclear Safety Authority confirms the classification of this radiation protection incident at level 2 on the INES scale.
This incident, which involves employees of the service responsible for monitoring the application of the radiation protection regulations, raises serious doubts about the organization of radiation protection on site and the procedures established by EdF for ensuring the protection against ionizing radiation of workers at nuclear power plants
Event date: Thu, 11-03-1999
