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Title: A brief history of NDA at the IAEA.

Nearly 30 years ago, the first portable nondestructive assay instrument, a SAM-II, was brought to Vienna for IAEA consideration. This initial foray into the usage of nondestructive assay (NDA) as an independent assessment tool has materialized into one of the important tools for IAEA inspections. NDA instruments have several inherent advantages for inspectors; their measurements generate no radioactive waste, provide immediate answers, do not require specialized operators, and can be either taken to the items to be measured (portable instruments), or the items for measurement can be brought to the instruments, such as can be applied in on-site IAEA laboratories or off-site IAEA lab at Siebersdorf. The SAM-II was a small, lightweight, battery-powered, gamma-ray instrument used for uranium enrichment measurements. It was also found to be usehl for locating nuclear material, distinguishing between uranium and plutonium, and determining the active length of items like fuel pins. However it was not well suited for determining the amount of bulk material present, except for small containers of low-density materials. A 6-sided neutron coincidence counter, easily disassembled so it could be shipped and carried by airplane, was developed for bulk measurements of plutonium. The HLNCC (High Level Neutron Coincidence Counter) was immediately usefulmore » for quantitative measurements of pure plutonium oxide. However, the IAEA had to make a trade-off between the ease of use of NDA instruments on-site, and the problems of obtaining small samples for shipment to an independent lab for more accurate analysis. NDA does not create radioactive waste, so as waste handling has become more cautious and more regulated, NDA looks better and better. After acceptance of NDA by the IAEA for routine use, the follow-up question was naturally, 'How much better can this measurement be made?' The Program for Technical Assistance to IAEA Safeguards (POTAS) supported multiple and varied efforts in this direction, such as improving both the plutonium isotopic distribution measurement and the multiplicity counter, so that the assays can be performed on any plutonium samples instead of only pure oxides. Advances have also been made on uranium bulk measurements by the development of the active well coincidence counter. Meanwhile, several large bulk-handling facilities have been coming on line under IAEA safeguards. These facilities require full-time inspectors to be present whenever the plant is operating. The IAEA requested help so that measurements can be made even when inspectors are not present. The evolution and success of unattended NDA has been responsible for the capability of the IAEA to monitor large bulk-handling facilities without substantial increase in inspection effort. The integration of NDA with containment & surveillance measures and automation has been crucial to reducing inspection manpower. These systems have developed to the point where the IAEA can make credible conclusions on large high-throughput plants such as mixed-oxide (MOX) fuel fabrication or reprocessing plants.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. (James K.)
  2. (Barbara J.)
  3. (Sin-Tao)
  4. (Mark E.)
Publication Date:
OSTI Identifier:
975621
Report Number(s):
LA-UR-01-3668
TRN: US1002504
Resource Type:
Conference
Resource Relation:
Conference: Presented at the Institute of Nuclear Materials Management 42nd Annual Meeting, Indian Wells, California, July 15-19, 2001.
Research Org:
Los Alamos National Laboratory
Sponsoring Org:
DOE
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; AUTOMATION; CONTAINERS; CONTAINMENT; FABRICATION; FUEL PINS; IAEA; IAEA SAFEGUARDS; ISOTOPE SEPARATION; MANPOWER; MONITORS; MULTIPLICITY; NEUTRONS; NUCLEAR MATERIALS MANAGEMENT; OXIDES; PLUTONIUM; PLUTONIUM OXIDES; RADIOACTIVE WASTES; REPROCESSING; URANIUM; WASTES