Development of NDA (Nondestructive Assay) Instruments for the Los Alamos SIS (Special Isotope Separation) Facility.

摘要

The Los Alamos Special Isotope Separation Facility produces special plutonium isotopes and converts plutonium scrap by using the molecular laser isotope separation (MLIS) process in a gaseous plutonium hexafluoride (PuF(sub 6)) phase. To provide important process-development and accountability information, we have developed and installed four nondestructive assay (NDA) instruments for that facility. These instruments are (1) an in-line plutonium isotopic analysis system to measure plutonium isotopes in gaseous, solid, and liquid phases, (2) an in-line sodium iodide (NaI) monitoring system consisting of six 2-in. by 2-in., two 2-in. by 24-in., and one 2-in. by 22-in. NaI detectors at specified components (a feed bottle, a feed-transfer cold trap, a compressor, a heat exchanger, a collector, a nozzle prefilter, and a tails cold trap) in the flow loop, (3) a portable high-resolution germanium gamma-ray system for plutonium isotopic analysis, and (4) a portable NaI gamma-ray holdup monitor. This paper discusses the measurement principles, hardware and software designs, and performance associated with these NDA instruments. 2 refs, 11 figs., 2 tabs.