The use of nuclear simulation calculations to support applications in radioactive tracer logging

Spectrum shape-analysis techniques applied to the Hanford Tank Farms spectral gamma logs

“…The shape of this continuum and its magnitude relative to the unscattered source radiation are sensitive to the intervening material and to the distribution of the source. Other researchers observed these spectral shape effects and exploited them in developing tracer logs for the petroleum industry (Gadeken et al 1991;Gartner et al 1990). Enhancement of the low-energy component of the gamma spectrum from 6oCo spectral gamma logs was recently interpreted as indicating the contaminant was inside the casing for a Hanford monitoring well at a crib disposal site (Gadeken et al 1995).…”

Radial distributions of /sup 60/Co contaminants surrounding wellbores at the Hanford Site

“…This is because these tools have steel housings and Figure 3 shows that the inside versus outside spectral differences are subtle above 150-keV. Nevertheless, the characteristics of borehole versus formation gamma ray signatures have been known for a number of years [ 101. The conclusion that the is inside the casing is based on extensive investigations related to HES's oil field work [3,4,5]. The question of how the radioisotope, 6oCo, came to be in its present location may be explained by adsorption to a rust layer inside the casing.…”

“…Experimental calibration procedures for borehole environments have been described previously [ 3,4] and numerical simulation calculations were performed to support this work [5]. For this CRADA the gamma ray spectroscopy adaptation requires that a unit spectrum be determinedl for several common gamma-ray-emitting radionuclides found on the Hanford Site.…”