Fifteen years of monitoring the surface aquifer of Saluggia: characterization of radioactive contamination and environmental impact

Abstract

A large part of the inventory of the Italian national radioactive waste and spent nuclear fuel, more than 80% in terms of activity, is kept at the Saluggia nuclear site. Over time, the site has housed a pilot plant for spent nuclear fuel reprocessing, a pilot plant for the manufacture of nuclear fuel, a research reactor with hot cells for testing irradiated material, plants for radiopharmaceuticals production, a repository for spent nuclear fuel and solid and liquid radioactive waste repositories as well. In this context of objective environmental criticality, a decades-long monitoring activity was carried out by ARPA Piemonte in the framework of the existing environmental radioactivity monitoring networks. A particularly interesting aspect of this activity is the monitoring of radioactive contamination of the surface aquifer. The monitoring of the aquifer is ensured by dozens of control wells distributed both inside and outside the plants. In some of these wells, traces of some radionuclides attributable to the nuclear activities of the plants, namely $^3$H, $^{60}$Co, $^{90}$Sr and $^{137}$Cs, were detected. The levels of these radioactive contamination, although relatively low and of poor radiological significance, are nevertheless an important indicator of the vulnerability of the aquifer in question and constitute a very important instrument for monitoring the radiological safety conditions of the site: the observed changes in concentration could allow a prompt detection of uncontrolled release phenomena attributable to the nuclear plants. In this paper are presented and discussed the contamination values recorded in the last fifteen years and their temporal evolution.