Bonrad, Radiometric remediation. A procedure in search of radioactive materials: sources, waste, building materials

Abstract

This procedure on radiometric risk is a preventive control, carried out with suitable instrumentation in industrial and non-industrial sites, where it is needed to activate environmental monitoring or remediation, even if information on the industrial processing cycle is available.

It is an ordinary prevention activity that Arpacal, the Regional Agency for Environmental Protection of Calabria, technicians use in advance when working in industrial sites or disused areas classified as potentially contaminated. This procedure was used in a former industrial area in Calabria. The area in question, approximately 10 hectares, was in an evident and advanced state of abandonment, containing waste of various origins and hazardousness, and was therefore in judicial custody. The control procedure applied, called BONRAD - Radiometric Reclamation - is based on the preventive verification of the levels of environmental radioactivity, in the locations frequented by the personnel involved, through measurements of the equivalent rate of environmental dose and surface contamination with the aim of:

1. estimatingthe environmental radioactivity background of the area trampled by personnel;
2. checking the presence of hot spots by recording radiometric anomalies;
3. performing gamma spectrometry measurements in the field to identify the radionuclides generating the possible anomaly;
4. radiological risk management.

The application of BONRAD allowed the identification of a part of the asphalt road, about 30 m², affected by an important radiometric anomaly: three radiometric detection instruments, with different characteristics and efficiencies, recorded a significant increase in the background of environmental radioactivity, over a factor of 10³ (BONRAD 2). The spectral analysis in the field found 8 sources of ²²⁶Ra. The area was therefore immediately banned and classified as contaminated by radionuclides (BONRAD 4).