Year
2014
Abstract
Detection and quantification of fissile material deposits, also termed holdup when it is considered as process residues in equipment , is an ongoing activity in many uranium processing facilities. A common measurement approach involves the use of portable scintillation based detection systems that, when suitably calibrated, provide s quantified measurements in terms of the gram content of 235 U present. We are exploring the de velopment of a more comprehensive portable detection system approach, intended to provide enhanced sensitivity over the dynamic range of enrichment levels while functioning within a high throughput measurements program. Crystal selection and collimator ge ometry are m atched to provide the best peak - to - background ratio for a given gamma detector field of view . Of particular importance is the need to address all aspects of a quality control program such as QSNDA 1) (Quality System for Non d estructive Assay Cha racterization ) that addresses all aspects of the quantification process from verification of detection geometry through to final data reporting. It is also important to maintain a continued safety focus where situations, such as sensing the presence of potential surface contamination might be a possibility. The gamma detection system discussed in this paper also utilizes an imaging micro - camera embedded into the front of the detector with the same field of view as the detector to provide parallax free i mages of the object being measured. This visualization, combined with automated object - distance remote measurement and laser markers allows the operator to properly orient the detector to the object of interest. Embedded LED illumination aids accommodati on of poorly lighted areas. The use of embedded image analysis and UV LEDs , built into the detector may help identify the potential presence of surface contaminants – alerting NDA personnel to unseen risk. A calibration approach is also being investigate d, termed Comprehensive Geometry Model (CGM) that addresses limitations and vulnerabilities experienced within the Generalized Geometry Holdup 2,3,4) approach . This model, based upon a calibration approach including both radial and source - detector distance measurements, overcomes limitations in the GGH geometry approximations. Models can still be rapidly generated and repetitive , more complex models can be generated and saved for use as required in a routine operations setting. Because the system can acce pt qualified detection models from other model programs, a variety of reportable measurements can be accomplished within a single working shift.