ASSAY EXPERIENCE WITH MONAL AT OAK RIDGE

The Mobile Nondestructive Assay Laboratory (MONAL, Fig. 1) was devel- oped by the Los Alamos Scientific Laboratory to test and demonstrate non- destructive assay techniques at various nuclear facilities and to perform routine scrap and waste measurements. Its major purpose is an interface between the nondestructive assay group at LASL and the nuclear community. The purpose of this paper is to report on recent operations at the USAEC facilities at Oak Ridge, Tennessee, and in so doing illustrate the variety of techniques and services associated with the laboratory. The mobile lab carries a wide range of nuclear assay equipment in an attempt to cover the spectrum of measurement problems. Active delayed neutron measurements can be performed with a 14 MeV neutron generator and a variety of high efficiency neutron detectors and spectrum tailoring assemblies. Gamma-ray assays are performed with the Ge(Li) segmented scan system shown in Figure 2. This system uses an external source attenuation correction and a combination of vertical collimation and scanning to cor- rect for sample inhomoeeneities. A thermal neutron coincidence counter 900 7An is available to measure the spontaneous fission signatures of •iJOU and ^HUP (see Figure 3) . This detector is presently on loan to the Oak Ridge Gas- eous Diffusion Plant (ORGDP) for evaluation.