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Methods and techniques of NDA (nondestructive assay)

Description: Nondestructive assay (NDA) refers to techniques and instruments developed to measure nuclear materials in the many forms in which they occur throughout the fuel cycle. These techniques were first developed to support nuclear safeguards inspections and nuclear material accountability; they are also used extensively for process and quality control. Most accountability measurements are based on analytical chemistry and require that a sample be drawn and analyzed destructively. Destructive analysis can not be applied to many of the product materials found in the fuel cycle, such as fuel rods and assemblies, because of their high monetary value. Also, many waste and scrap materials can not be adequately sampled for destructive analysis because of their heterogenous nature. This situation led to the development of nondestructive analysis techniques. This paper presents an overview of the major NDA techniques and instrumentation in use today. The instrumentation described below is now used frequently by safeguards inspectors and facility operators alike. 19 refs., 18 figs., 4 tabs.
Date: January 1, 1988
Creator: Reilly, T.D.
Partner: UNT Libraries Government Documents Department

Gamma-ray measurements for uranium enrichment standards

Description: The gamma-ray spectroscopic measurement of uranium enrichment is one of the most widely used nondestructive analysis techniques. A study has been started of the precision and accuracy achievable with this technique and the physical parameters which affect it. The study was prompted by questions raised during the ongoing ESARDA-NBS experiment to produce uranium oxide reference counting materials for the technique. Results reported using a high-quality Ge(Li) spectrometer system show reproducibility comparable to that attainable with mass spectrometry (approximately 0.1% for low enrichment uranium).
Date: January 1, 1979
Creator: Reilly, T.D.
Partner: UNT Libraries Government Documents Department

Measurement of leached hulls

Description: Leached hulls are the short lengths of fuel rod cladding and fuel element hardware which constitute a major waste product of a reprocessing plant employing a chop-and-leach head-end process. The small, undissolved fuel residue (0.1 to 1.0% of original fuel content) which is discarded with this waste must be measured for safeguards, material accountability, and process control reasons. This report gives a critical analysis of hull measurement techniques involving the analysis of fission product gamma rays, spontaneous fission neutrons from curium, and delayed neutron activation. Major emphasis is given to the measurement of 2186-keV gamma rays from /sup 144/Ce--/sup 144/Pr. A detailed description of typical leached hull characteristics is presented at the beginning of the report. An extensive review of experience gained from existing hull measurement systems in the United Kingdom, France, Japan, Germany, Italy, and the United States is presented.
Date: July 1, 1979
Creator: Reilly, T.D.
Partner: UNT Libraries Government Documents Department

UF$sub 6$ enrichment monitor: operating procedures manual

Description: This manual describes the construction and operation of a UF/sub 6/ enrichment monitor for the continuous measurement of percent /sup 235/U and percent /sup 234/U in a liquid UF/sub 6/ stream. The system uses a gamma enrichment meter to measure /sup 235/U and /sup 3/He neutron detectors to measure /sup 234/U. It is presently installed at the Goodyear Atomic Corporation gaseous diffusion plant in Piketon. Ohio. (auth)
Date: January 1, 1974
Creator: Reilly, T.D.; Martin, E.R. & Parker, J.L.
Partner: UNT Libraries Government Documents Department

The verification of reactor operating history using the fork detector

Description: A technique has been developed for verification of light-water reactor operating history from measurements of irradiated fuel assemblies. The Fork detector is used to measure neutron and gross gamma-ray emissions from fuel assemblies. The measurements can be performed a few days after discharge or up to several years later. The neutron and gamma-ray ratios are used to check the consistency of the declared number of irradiated cycles for the assembly in the core. Reactor burnup calculation codes are used to correct the measured neutron rates for different initial enrichments and discontinuous irradiation histories. We have modified the Fork detector so that it can operate in the intense gamma-ray field emitted from freshly discharged fuel. This modification makes it possible to perform fuel verification during the annual fuel-reload and maintenance period.
Date: July 1, 1996
Creator: Menlove, H.O.; Reilly, T.D. & Siebelist, R.
Partner: UNT Libraries Government Documents Department

NDA (nondestructive assay) training for new IAEA inspectors at Los Alamos

Description: The history of the evolution of nondestructive assay (NDA) training for international inspectors at Los Alamos is described. The current NDA training course for International Atomic Energy Agency inspectors is presented in terms of structure, content, and rationale. Results of inspector measurement exercises are given along with projections for future developments in NDA inspector training. 3 refs.
Date: January 1, 1987
Creator: Stewart, J.E.; Reilly, T.D.; Belew, W.; Woelfl, E. & Fager, J.
Partner: UNT Libraries Government Documents Department

Advances in nuclear instrumentation for safeguards

Description: This paper describes detectors, instrumentation, and analytical methods under development to address the above issues. The authors will describe work underway on room-temperature semiconductors including attempts to model the response of these detectors to improve spectrum analysis procedures and detector design. Computerized tomography is used in many medical and industrial applications; they are developing both gamma-ray and neutron tomography for improved measurements of waste and direct-use materials. Modern electronics and scintillation detectors should permit the development of fast neutron coincidence detectors with dramatically improved signal-to-noise ratios. For active measurements, they are studying several improved neutron sources, including a high-fluence, plasma-based, d-t generator. New analysis tools from information theory may permit one to better combine data from different measurement systems. This paper attempts to briefly describe a range of new sensors, electronics, and data analysis methods under study at Los Alamos and other laboratories to promote discussion of promising technology that they may bring to bear on these important global issues.
Date: December 31, 1996
Creator: Prettyman, T.H.; Reilly, T.D.; Miller, M.C.; Hollas, C.L.; Pickrell, M.M.; Prommel, J.M. et al.
Partner: UNT Libraries Government Documents Department

Implementation of neutron counting techniques at US facilities for IAEA verification of excess materials from nuclear weapons production

Description: The U.S. Nonproliferation and Export Control Policy, announced by President Clinton before the United Nations General Assembly on September 27, 1993, commits the U.S. to placing under International Atomic Energy Agency (IAEA) Safeguards excess nuclear materials no longer needed for the U.S. nuclear deterrent. As of July 1, 1995, the IAEA had completed Initial Physical Inventory Verification (IPIV) at two facilities: a storage vault in the Oak Ridge Y-12 plant containing highly enriched uranium (HOW) metal and another storage vault in the Hanford Plutonium Finishing Plant (PFP) containing plutonium oxide and plutonium-bearing residues. Another plutonium- storage vault, located at Rocky Flats, is scheduled for the IPIV in the fall of 1995. Conventional neutron coincidence counting is one of the routinely applied IAEA nondestructive assay (ND) methods for verification of uranium and plutonium. However, at all three facilities mentioned above, neutron ND equipment had to be modified or developed for specific facility needs such as the type and configuration of material placed under safeguards. This document describes those modifications and developments.
Date: August 1, 1995
Creator: Stewart, J.E.; Krick, M.S.; Langner, D.G.; Reilly, T.D.; Theis, W.; Lemaire, R.J. et al.
Partner: UNT Libraries Government Documents Department