A good practice guide for the use of modelling codes in non destructive assay of nuclear matter

The IAEA has requested that the accepted principles of best practice for the use of radiometric modelling codes, in the Non Destructive Assay (Nda) field of the nuclear industry, should be documented. These include various code types, from discrete ordinate and Monte Carlo transport codes, to reactor physics burnup codes. In the nuclear industry, these codes are used for a variety of application domains including nuclear material safeguards, to waste assay and environmental remediation. The intention of this guide, by documenting best practice, is to both provide confidence for technical, management and regulatory staff, in the validity of the results of modelling codes, and provide a convenient knowledge base for technical staff in this highly specialist field. A specialist group of experts was convened under the auspices of the ESARDA Nda working group, seeking specialist input from recognized experts in the industry as appropriate. The resulting good practice guide is not intended as an exhaustive, prescriptive document. Rather, it is hoped that practitioners, managers and regulators, can use the document to provide guidance as to acceptable practices governing the use of these specialist codes. It should be noted that some degree of prior familiarity with the physics, codes, modelling techniques and applications is assumed; the guide is not suitable for a complete novice. Following introductory remarks, scope and overview of modelling methods the bulk of the guide is contained in 7 targeted sections. These set out good practice associated with key aspects which are: Problem definition, Benchmarking / validation, Training / competency, Quality Assurance, Nuclear Data, Physics treatments, Uncertainties. A reference list is provided allowing the reader to explore specific aspects in detail. For ease of reference an Appendix summarising important basic nuclear data is provided. It is concluded that modelling tools are well developed and in widespread use and, properly applied are powerful and accurate. It is anticipated that the state of best practice will continue to evolve.