Clearance monitoring using hand-held devices: operational implementation and challenges

Clearance monitoring includes all measures taken and measurements performed to ensure that all pertinent regulatory conditions are met for clearance of waste material. For bulk material, only a limited number of monitoring techniques are feasible for providing the necessary proof of compliance in the time frames and at costs commensurate with operator and regulator expectations for decommissioning projects. Operationally, measurements using hand-held devices, such as contamination monitors using scintillator or proportional counter technology, might provide sufficiently short response times at acceptable accuracies to segregate the waste streams according to their level of contamination and allowing for a decision on their further processing. Recognizing the various limitations hand-held devices might display in bulk material screening during clearance monitoring measurements, the detection limits with respect to material self-attenuation and non-homogenous activity distributions have been investigated.