Reactor flux measurements using thermoluminescent dosimetry

Journal Article · Mon Nov 01 04:00:00 EST 1976 · Nucl. Technol.; (United States)

OSTI ID:7331219

McKlveen, J W ^[1]; Schwenk, M

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1. Arizona State Univ., Tempe

Thermoluminescent dosimetry (TLD) was successfully evaluated as an in-core thermal-neutron-flux determinant. The LiF crystals enriched with either /sup 6/Li or /sup 7/Li provided two effective neutron-gamma discrimination techniques. The first method used both types of crystals. The /sup 6/LiF dosimeters, which have large thermal-neutron cross sections, detected both neutrons and gamma radiation, while the /sup 7/LiF dosimeters, possessing negligible thermal-neutron attenuation characteristics, monitored the gamma component only. The dosimeters were inserted into a reactor for a known time interval and read on a commercially available detection system, and the difference in dosimeter exposure yielded a direct measure of neutron flux. The second technique used bare and cadmium-covered /sup 7/LiF dosimeters. The bare crystals detected reactor gammas, while those encapsulated in cadmium measured reactor gammas plus capture gammas from the Cd(n,..gamma..) reaction. The difference in exposures provided the capture-gamma contribution, which was proportional to reactor flux. Experiments using a subcritical and a TRIGA reactor revealed exposure rate to neutron flux sensitivities of 1.4 x 10/sup -7/ R/sec per phi and 2.6 x 10/sup -8/ R/sec per phi for the respective techniques. Accurate flux measurements were obtained over a range spanning 10/sup 2/ to 10/sup 12/ n/(cm/sup 2/ sec). At higher fluxes, the dosimeters experienced radiation damage and readings became unreliable. The TLD results were compared against BF/sub 3/ detection, foil activation, and fission chambers to derive an empirical exposure rate to the flux conversion factor.

• OSTI ID: 7331219
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 31:2; ISSN NUTYB
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200* -- Nuclear Reactor Technology-- Components & Accessories
440102 -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALKALI METAL COMPOUNDS
DOSEMETERS
DOSIMETRY
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
IN CORE INSTRUMENTS
LITHIUM COMPOUNDS
LITHIUM FLUORIDES
LITHIUM HALIDES
LUMINESCENT DOSEMETERS
MEASURING INSTRUMENTS
MONITORING
NEUTRON FLUX
PERFORMANCE TESTING
RADIATION FLUX
REACTOR INSTRUMENTATION
TESTING
THERMOLUMINESCENT DOSEMETERS
THERMOLUMINESCENT DOSIMETRY