A passive neutron counter for determination of transuranics in high gamma activity samples
The measure of transuranic content in nuclear waste is complicated by the fact that transuranics include a broad spectrum of radioactive decays without any features in common. This paper describes a very sensitive neutron counting instruments which can determine the presence of small quantities of transuranic materials in samples emitting extremely high levels of gamma radiation and which can also determine the isotopic content. The detector is modular to facilitate disassembly for maintenance or decontamination and consists of a neutron counter with internal and external radiation shields. The external shield, designed to minimize the ambient neutron background, is an annular tank containing a saturated aqueous solution of boric acid. The counter module is an annular array of 80 BF/sub 3/ proportional counting tubes arranged in two concentric rows of 40 tubes surrounded by a polyethyene moderator. The internal shield, a lead annulus 10 cm thick, separates the sample chamber from the detector array. The sample chamber accepts a five-gallonbucket sized sample. Gamma radiation levels of greater than 100,000 R/hr can be tolerated without affecting the neutron count rate. Each tube is fitted with a preamplifier/discriminator so that the entire array can operate in the same gamma environment as a single tube. The electronics permits measurements in a coincidence mode, for isotopic composition measurement, and a spatial mode, for determining the physical distribution of transuranics in the sample.
- Research Organization:
- Pacific Northwest Lab., Richland, WA 99352
- OSTI ID:
- 6853702
- Report Number(s):
- CONF-831015-
- Journal Information:
- IEEE Trans. Nucl. Sci.; (United States), Journal Name: IEEE Trans. Nucl. Sci.; (United States) Vol. 31:1; ISSN IETNA
- Country of Publication:
- United States
- Language:
- English
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500300 -- Environment
Atmospheric-- Radioactive Materials Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALPHA-BEARING WASTES
AMPLIFIERS
ANTICOINCIDENCE
AQUEOUS SOLUTIONS
BF3 COUNTERS
BORIC ACID
COINCIDENCE METHODS
COUNTING RATES
COUNTING TECHNIQUES
DESIGN
DETECTION
DISCRIMINATORS
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
GAMMA RADIATION
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IONIZING RADIATIONS
ISOTOPE RATIO
LEAD
MATERIALS
MEASURING INSTRUMENTS
METALS
MIXTURES
NEUTRON DETECTION
NEUTRON DETECTORS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PERFORMANCE
POLYETHYLENES
POLYMERS
POLYOLEFINS
PREAMPLIFIERS
PROPORTIONAL COUNTERS
RADIATION DETECTION
RADIATION DETECTORS
RADIATIONS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SAMPLERS
SENSITIVITY
SHIELDING MATERIALS
SOLUTIONS
WASTES