Four decades of progress in PWRs surveillance program dosimetry measurements at the MADERE platform

Abstract

Since 1981, the French Alternative Energies and Atomic Energy Commission has been measuring the dosimeters of the surveillance capsules of the French pressurized water reactors and assessing their neutron fluence. This represents more than 250 surveillance PWR capsules, i.e. 4 thousands dosimeters. Started in Grenoble, this work continued in Cadarache with the creation of the “Measurement Applied to DosimEtry in Reactors” (MADERE) platform within the Dosimetry, Sensors and Instrumentation Laboratory (LDCI). Since 1998, all surveillance dosimeters measurements (i.e. Al-Co, 238U, 237Np, Ni, Cu, Fe and Nb) have been performed at MADERE under the “Cofrac Essais” accreditation according to the ISO/IEC 17025 international standard. The evolution over time of the 1σ measurement uncertainty of the activity of each is presented in this paper. Since 2015, they are [±1.3% ; ±2.9%] for 238U with Ni encapsulation, [±0.8% ; ±2.1%] for 238U with Ti encapsulation, [±1.2% ; ±4.9%] for 238U with stainless steel encapsulation, ±1.3% for 237Np dosimeters, ±1.2% for Al-Co, [±1.2% ; ±1.4%] for nickel, copper and iron, [±3.3%; ±3.9%] for niobium if unbroken after irradiation.