Characterization of Beta Emitters for Decommissioning

Abstract

Radioactive waste management is nowadays, after nearly 50 years of concern, a technical and economical challenge faced by existing nuclear power countries. In decommissioning of nuclear facilities after removal of the nuclear equipment (laboratory materials, glove boxes, etc.), the radioactive inventory of the various building materials is needed to state the working condition for dismantling. Thus, characterization is essential for decommissioning and moreover for radioactive waste classification and management. A radionuclide imaging technique, the Digital Autoradiography (DA), also known as storage phosphor technology, has been studied for decommissioning projects because of its advantages such low price, easy utilization and sensitivity. DA has been proven to be an efficient technic in localization of beta emitter (especially C-14 and H-3) contamination remaining in nuclear facilities under dismantling. Samples have been collected where C-14 or H-3 have been observed by DA and analyzed by the classical technique : pyrolysis followed by liquid scintillation counting. Real applications to classify potential waste coming from a laboratory under dismantling are described in this paper.

Measurement of low-activity uranium contamination by gamma-ray spectrometry for nuclear decommissioning

“…Depending on the past operations conducted in the facility, different contaminations may be expected. Uranium-based contamination, in particular, emits three main signals: alpha particles [2], beta particles [3] and gamma rays [4]. Since all three come from the same decay chain, consequently, determining either activity can lead to the total contamination activity.…”

“…depending on the studied gamma ray, whether it is from the 238 U decay chain, or the 235 U one. The simulated concrete block is 100 × 100 × 25 cm 3 . A thickness of 25 centimeters has been chosen for a compromise between the calculation convergence and the accuracy of the concrete background signal [20].…”

A Reliable Absolute and Relative Bayesian Method for Nuclear Decommissioning: Low-Level Radioactivity Detection With Gamma-Ray Spectrometry

“…Alpha, beta and gamma emissions are three distinct signatures [3][4][5] for measuring a potential radiological contamination involving uranium isotopes; namely, uranium 234, 235 and 238 (U-234, U-235, U-238). Alpha emission has the advantage of being homogenous with the decommissioning criteria.…”