Advanced Non-Destructive Assay Systems and Special Instrumentation Requirements for Spent Nuclear Fuel Recycling Facilities - 8032

摘要

The safe and efficient operation of the next generation of Spent Nuclear Fuel (SNF) recycling / reprocessing facilities is dependent upon the availability of high performance real time Non-Destructive Assay (NDA) systems at key in-line points. A diverse variety of such special instrument systems have been developed and commissioned at reprocessing plants worldwide over the past fifty years.. The measurement purpose, technique and plant performance for selected key systems have been reviewed. Obsolescence issues and areas for development are identified in the context of the measurements needs of future recycling facilities and their associated waste treatment plants. Areas of concern include (ⅰ) Materials Accountancy and Safeguards, (ⅱ) Head End process control and feed envelope verification, (ⅲ) Real-time monitoring at the Product Finishing Stages, (ⅳ) Criticality safety and (v) Radioactive waste characterization.Common characteristics of the traditional NDA systems in historical recycling facilities are (ⅰ) In-house development of bespoke instruments resulting in equipment that if often unique to a given facility and generally not commercially available, (ⅱ) Use of 'novel' techniques - not widely deployed in other applications, (ⅲ) Design features that are tailored to the specific plant requirements of the facility operator, (ⅳ) Systems and software implementation that was not always carried out to modern industry standards and (v) A tendency to be overly complex -refined by on-plant operational usage and experience.Although these systems were 'validated in use' and are generally fit for purpose, there are a number of potential problems in transferring technology that was developed ten or more years ago to the new build SNF recycling facilities of the future. These issues include (ⅰ) Obsolescence of components - particularly with respect to computer hardware and data acquisition electronics, (ⅱ) Availability of Intellectual Property and design drawings and documentation (ⅲ) Lack of compatibility with modern computers, software, data transfer networks, digital protocols and electrical code standards, (ⅳ) Non-compliance with current and future mandatory standards and regulations for nuclear facilities (v) Design focused on measurement and control points that may be specific to the facility process (vi) Lack of utilization of recent technological advances where better performing, less complex and more cost-effective options are now available.Key radiometric measurement drivers and control points for future recycling facilities have been determined and a review of the adequacy of existing instrumentation has been performed. Areas where recent technology improvements may be more effectively deployed and future technology development may be appropriate are identified.