Counting techniques applied to fabrication of nondestructive assay standards for the National TRU Waste Program

NUCL 45

Sandra L. Mecklenburg1, Amy S. Wong2, and Denise L. Thronas2. (1) Actinide Analytical Chemistry, Los Alamos National Laboratory, P.O. Box 1663, MS G740, Los Alamos, NM 87545, (2) NMT-9, Los Alamos National Laboratory, MS E502, Los Alamos, NM 87545
The National TRU Waste Program requires traceable nuclear material standards for certification of non-destructive assay instrumentation used to quantify nuclear material in DOE-generated waste before shipment for final disposition at the Waste Isolation Pilot Plant (WIPP). Over 170 standards containing various isotopes of plutonium, americium, or uranium dispersed in an inert matrix have been fabricated and certified. A number of counting techniques were employed in characterization of the feedstock nuclear materials, as well as in characterization of the completed standards. Radiochemical analyses of americium, neptunium, uranium, californium, and curium content of starting materials were performed using gross alpha counting, alpha spectroscopy, and gamma-ray spectroscopy. Homogeneity of nuclear material-matrix blends was measured before encapsulation by gamma-ray methods. Holdup measurements were performed on fabrication tools used to more accurately quantify the nuclear material content of each standard. Finally, gamma-ray measurements were performed on completed standards to verify their uniformity and content.