Development of a radiochemical sensor, Part 2: Application to liquid effluents

Monitoring programmes to evaluate the impact of nuclear activities on the environment require an increasing number of analytical determinations. In such a scenario, the development of a sensor could be especially helpful to increase the limited analytical capabilities of laboratories. The present study continues an initial feasibility project and focuses on the evaluation of the capabilities of a radiochemical sensor for liquid effluents applicable to real samples. This sensor is capable of sending information about the specific activity and volume of a contamination episode to a remote position, on-line and continuously. The sensor is made of plastic scintillator beads and includes two receptors, one for alpha and beta particles and the other for gamma radiations. Contamination pulses of 90Sr/90Y, 134Cs and 240Pu of different volumes and activity levels included in a continuous stream were quantified. Relative errors obtained for both magnitudes are, in the majority of the cases, less than 10%. Lower limits for these quantifications are 5 ml and around 1 Bq/ml. These thresholds could be improved in new designs adapted to specific problems.