Neutron flux and spectrum characterization in the University of Illinois TRIGA
- University of Illinois at Urbana-Champaign, IL (United States)
The principal irradiation facilities at the University of Illinois TRIGA are a central thimble, a pneumatic 'rabbit' tube in the G-hexagon, a forty- position Lazy Susan facility in the reflector, a through-port passing tangentially through the reflector, and a recently installed rotating tube in a three-element cluster position in the F- and G-hexagons. These facilities are used primarily for thermal and epithermal neutron activation, and for radiation damage studies in semiconductor and other materials. Thermal and epithermal neutron fluence rates have recently been measured by means of radiometric monitors in all the core and reflector facilities at a variety of reactor power levels. In addition, the fast neutron fluences have been characterized by means of threshold and non-threshold activation reaction rates measured in those positions used for radiation damage studies. Unfolding of neutron spectra from the measured reaction rates was done by means of the code LSL-M2, which was made available in 1986 from the Radiation Shielding Information Center. This code uses the generalized least squares method and incorporates a full propagation of uncertainties due to errors in measured reaction rates, cross section data, and input neutron spectra. The input spectra, needed in LSL-M2, were taken from the General Atomic report GA4361 which includes 24-group spectra, calculated by the code GAZE, for the center of the core, the F-hexagon and the Lazy Susan. These positions, and some of the material and geometrical specifications, do not correspond exactly with the actual ones at the University of Illinois TRIGA, but the differences in the neutron spectra were found to be small. The unfolded neutron spectra may be used to obtain fast neutron spectrum parameters needed in radiation damage studies and hardness testing. For example, the 1-MeV equivalent fluence rates for displacement damage in silicon, calculated according to the ASTM Standard E722, are reported. (author)
- Research Organization:
- General Atomics, San Diego, CA (United States)
- OSTI ID:
- 21165902
- Report Number(s):
- INIS-US-09N0295; TOC-20; TRN: US09N0305042482
- Resource Relation:
- Conference: 11. biennial U.S. TRIGA users' conference, Washington, DC (United States), 10-13 Apr 1988; Other Information: Country of input: International Atomic Energy Agency (IAEA); 5 refs, 4 figs, 4 tabs; Related Information: In: 11. biennial U.S. TRIGA users' conference. Papers and abstracts, 426 pages.
- Country of Publication:
- United States
- Language:
- English
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