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Title: Mobile neutron/gamma waste assay system for characterization of waste containing transuranics, uranium, and fission/activation products

Technical Report ·
OSTI ID:111754
 [1]; ;  [2]
  1. Canberra Industries, Inc., Meriden, CT (United States)
  2. Pacific Northwest Lab., Richland, WA (United States)

A new integrated neutron/gamma assay system has been built for measuring 55-gallon drums at Pacific Northwest Laboratory. The system is unique because it allows simultaneous measurement of neutrons and gamma-rays. This technique also allows measurement of transuranics (TRU), uranium, and fission/activation products, screening for shielded Special Nuclear Material prior to disposal, and critically determinations prior to transportation. The new system is positioned on a platform with rollers and installed inside a trailer or large van to allow transportation of the system to the waste site instead of movement of the drums to the scanner. The ability to move the system to the waste drums is particularly useful for drum retrieval programs common to all DOE sites and minimizes transportation problems on the site. For longer campaigns, the system can be moved into a facility. The mobile system consists of two separate subsystems: a passive Segmented Gamma Scanner (SGS) and a {open_quotes}clam-shell{close_quotes} passive neutron counter. The SGS with high purity germanium detector and {sup 75}Se transmission source simultaneously scan the height of the drum allowing identification of unshieled {open_quotes}hot spots{close_quotes} in the drum or segments where the matrix is too dense for the transmission source to penetrate. Dense segments can flag shielding material that could be used to hide plutonium or uranium during the gamma analysis. The passive nuetron counter with JSR-12N Neutron Coincidence Analyzer measures the coincident neutrons from the spontaneous fission of even isotopes of plutonium. Because high-density shielding produces minimal absorption of neutrons, compared to gamma rays, the passive neutron portion of the system can detect shielded SNM. Measurements to evaluate the performance of the system are still underway at Pacific Northwest Laboratory.

Research Organization:
Univ. of Arizona, Tucson, AZ (United States). Coll. of Engineering and Mines; New Mexico State Univ., Las Cruces, NM (United States); Waste-Management Education and Research Consortium (WERC), Las Cruces, NM (United States); US Department of Energy (USDOE), Washington DC (United States)
OSTI ID:
111754
Report Number(s):
CONF-940225-Vol.1; TRN: 95:021849
Resource Relation:
Conference: Waste management `94: working towards a cleaner environment, Tucson, AZ (United States), 27 Feb - 3 Mar 1994; Other Information: PBD: 1994; Related Information: Is Part Of Technology and programs for Radioactive Waste Management and Environmental Restoration. Volume 1; Post, R.G. [ed.] [Arizona Univ., Tucson, AZ (United States). Coll. of Engineering and Mines]; PB: 814 p.
Country of Publication:
United States
Language:
English