Experimental verification of modeling results for a PGNAA system for nondestructive assay of RCRA metals in drums
The use of pulsed gamma neutron activation analysis (PGNAA) for the nondestructive assay of mercury, cadmium and lead in a concrete matrix has been demonstrated. Calculations have also been performed to study interference with PGNAA detection sensitivity resulting from the presence of 238U, 235U, and 239Pu at levels expected in mixed waste. Analyses based on transport calculations examined the effects of these nuclides on neutron kinetics, and the contribution from the capture, fission and decay gamma-rays emitted by the nuclides to the gamma-ray spectrum. These calculations predicted insignificant effects on the system's detection limits (115, 9 and 4400 ppm for Hg, Cd and Pb, respectively, for a 2000 s assay). This paper describes verification measurements recently conducted using samples of 235U and 231U in the test drum geometry, which have provided experimental confirmation of the modeling results.
Dulloo
AR
Westinghouse Science and Technology Center, Pittsburgh, PA, USA. dullooar@westinghouse.com
Ruddy
FH
Congedo
TV
Seidel
JG
McIlwain
ME