This open access book describes the nondestructive assay techniques that are used for the measurement of nuclear material (primarily uranium and plutonium) for nuclear material accountancy purposes. It is a substantial revision to the so-called PANDA manual that has been a standard reference since its publication in 1991. The book covers the origin and interactions of gamma rays and neutrons as they affect nuclear measurements and also describes the theory and practice of calorimetry. The book gives a description of many instruments based on these techniques that are applied in the field. Although the basic physics has not changed since PANDA was first published, the last thirty years have seen many advances in analysis methods, instrumentation, and applications. The basic descriptions of the origin and interactions of radiation have been updated and include newer references. There have been extensive revisions of the description of gamma detection methods, attenuation correction procedures, and analysis methods, including for the measurement of uranium enrichment and the determination of plutonium isotopic composition. Extensive revisions and additions have also been made to the description of neutron detectors and to the explanation of neutron coincidence techniques. The chapter on neutron multiplicity techniques is a new addition to this edition. The applications of gamma and neutron techniques have been completely overhauled to remove obsolete systems and to include many current applications. The values of, and references to, nuclear data have been updated. This updated edition is an essential reference for academic researchers and practitioners in the field. This is an open access book.

A high-quality materials accounting system and effective international inspections in uranium fuel-fabrication facilities depend heavily upon accurate nondestructive assay measurements of the facilitys̀ nuclear materials. While item accounting can monitor a large portion of the facility inventory (fuel rods, assemblies, storage items), the contents of all such items and mass values for all bulk materials must be based on quantitative measurements. Weight measurements, combined with destructive analysis of process samples, can provide highly accurate quantitative information on well-characterized and uniform product materials. However, to cover the full range of process materials and to provide timely accountancy data on hard-to-measure items and rapid verification of previous measurements, radiation-based nondestructive assay (NDA) techniques play an important role. NDA for uranium fuel fabrication facilities relies on passive gamma spectroscopy for enrichment and U isotope mass values of medium-to-low-density samples and holdup deposits; it relies on active neutron techniques for U-235 mass values of high-density and heterogeneous samples. This paper will describe the basic radiation-based nondestructive assay techniques used to perform these measurements. The authors will also discuss the NDA measurement applications for international inspections of European fuel-fabrication facilities.

Prior to disposal, nuclear waste must be accurately characterized to identify and quantify the radioactive content. The DOE Complex faces the daunting task of measuring nuclear material with both a wide range of masses and matrices. Similarly daunting can be the selection of a non-destructive assay (NDA) technique(s) to efficiently perform the quantitative assay over the entire waste population. In fulfilling its role of a DOE Defense Programs nuclear User Facility/Technology Development Center, the Los Alamos National Laboratory Plutonium Facility recently tested three commercially built and owned, mobile nondestructive assay (NDA) systems with special nuclear materials (SNM). Two independent commercial companies financed the testing of their three mobile NDA systems at the site. Contained within a single trailer is Canberra Industries segmented gamma scanner/waste assay system (SGS/WAS) and neutron waste drum assay system (WDAS). The third system is a BNFL Instruments Inc. (formerly known as Pajarito Scientific Corporation) differential die-away imaging passive/active neutron (IPAN) counter. In an effort to increase the value of this comparison, additional NDA techniques at LANL were also used to measure these same drums. These are comprised of three tomographic gamma scanners (one mobile unit and two stationary) and one developmental differential die-away system. Although not certified standards, the authors hope that such a comparison will provide valuable data for those considering these different NDA techniques to measure their waste as well as the developers of the techniques.