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Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements

Conference:

Abstract

Conventional activation and reactivity measurements of the nuclear Doppler Effect have been limited to temperatures of about 2000{sup o}K because of problems with furnace equipment. There is a need for Doppler data at higher temperatures for design of reactors and analysis of reactor accidents. To fill this need, a novel technique using pulsed-mode operation of a TRIGA reactor has been developed at the University of Wisconsin. This new method, the Pulsed Activation Doppler (PAD) technique, has been used successfully for high temperature Doppler measurements of UO{sub 2} fuel pellets. In the PAD technique, UO{sub 2} test pellets were doped with varying amounts of U-235, with fissile enrichments varying from 0.22% to 12% by weight. The pellets were encapsulated in individual irradiation cells and electrically preheated to predetermined temperatures. Pyrofoam-graphite heaters were used to give preheat temperatures of up to 1720 deg. K. The cells were then positioned in the University of Wisconsin TRIGA reactor core and pulse-irradiated. During the rapid irradiation, adiabatic fission energy deposition occurred in the pellets and very high temperatures (over 3115 deg, K) were attained. Corresponding resonance neutron captures occurred at the elevated temperatures. The Doppler Ratio was deduced from the gamma activities of the Np-239  More>>
Authors:
Foell, W K; Cashwell, R J; Bhattacharyya, S K; [1]  Russell, G J [2] 
  1. Argonne National Laboratory, Argonne, IL (United States)
  2. Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)
Publication Date:
Jul 01, 1974
Product Type:
Conference
Report Number:
INIS-US-09N0328; TOC-5
Resource Relation:
Conference: 3. TRIGA owners' conference, Albuquerque, NM (United States), 25-27 Feb 1974; Other Information: Country of input: International Atomic Energy Agency (IAEA); 2 figs; Related Information: In: 3. TRIGA owners' conference. Papers and abstracts, 432 pages.
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; CORRELATIONS; DOPED MATERIALS; EXTRAPOLATION; FUEL PELLETS; GRAPHITE; NEPTUNIUM 239; PULSED IRRADIATION; REACTOR ACCIDENTS; REACTOR CORES; RESONANCE INTEGRALS; RESONANCE NEUTRONS; TEMPERATURE RANGE 1000-4000 K; TRIGA TYPE REACTORS; URANIUM 235; URANIUM DIOXIDE
OSTI ID:
21217745
Research Organizations:
General Atomic Co., San Diego, CA (United States)
Country of Origin:
United States
Language:
English
Other Identifying Numbers:
TRN: US09N0352086529
Availability:
Available from INIS in electronic form
Submitting Site:
INIS
Size:
page(s) 4.29-4.34
Announcement Date:
Oct 19, 2009

Conference:

Citation Formats

Foell, W K, Cashwell, R J, Bhattacharyya, S K, and Russell, G J. Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements. United States: N. p., 1974. Web.
Foell, W K, Cashwell, R J, Bhattacharyya, S K, & Russell, G J. Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements. United States.
Foell, W K, Cashwell, R J, Bhattacharyya, S K, and Russell, G J. 1974. "Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements." United States.
@misc{etde_21217745,
title = {Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements}
author = {Foell, W K, Cashwell, R J, Bhattacharyya, S K, and Russell, G J}
abstractNote = {Conventional activation and reactivity measurements of the nuclear Doppler Effect have been limited to temperatures of about 2000{sup o}K because of problems with furnace equipment. There is a need for Doppler data at higher temperatures for design of reactors and analysis of reactor accidents. To fill this need, a novel technique using pulsed-mode operation of a TRIGA reactor has been developed at the University of Wisconsin. This new method, the Pulsed Activation Doppler (PAD) technique, has been used successfully for high temperature Doppler measurements of UO{sub 2} fuel pellets. In the PAD technique, UO{sub 2} test pellets were doped with varying amounts of U-235, with fissile enrichments varying from 0.22% to 12% by weight. The pellets were encapsulated in individual irradiation cells and electrically preheated to predetermined temperatures. Pyrofoam-graphite heaters were used to give preheat temperatures of up to 1720 deg. K. The cells were then positioned in the University of Wisconsin TRIGA reactor core and pulse-irradiated. During the rapid irradiation, adiabatic fission energy deposition occurred in the pellets and very high temperatures (over 3115 deg, K) were attained. Corresponding resonance neutron captures occurred at the elevated temperatures. The Doppler Ratio was deduced from the gamma activities of the Np-239 in the heated and unheated reference pellets. UO{sub 2} pellets of two nominal diameters, 210 mils (a surface-to-mass ratio, s/m = 1.1 cm{sup 2} /gm) and 360 mils (s/m = 0.63 cm{sup 2}/gm), were used for the experiments. For the 210 mil diameter pellets there was very good agreement between experimental results and Doppler ratios predicted both from extrapolations of the Hellstrand low-temperature resonance integral correlations and from GAROL calculations. Significantly, the agreement was good even for those pellets which experienced extensive melting. For the 360 mil diameter pellets the theoretical predictions were 10-15% lower than experimentally measured values. Explicit correlations for the Doppler Ratio were derived from the results of the present work. Since the Doppler Ratios were measured over a range of temperatures in the PAD experiment, effective static temperatures were defined for use in the correlations. The PAD technique has provided a significant advance in the field of high-temperature Doppler Measurements, extending the temperature range of the measurements by about 1000 deg. K. To the best knowledge of the authors, this is the first study of the Doppler Ratio under partially molten conditions of UO{sub 2}. (author)}
place = {United States}
year = {1974}
month = {Jul}
}