Reactor high flux isotope

Uranium-235 Enrichment. The enrichment of uranium is expressed as the weight percent of in uranium. For natural uranium the enrichment level is 0.72%. Many appHcations of uranium requite enrichment levels above 0.72%, such as nuclear reactor fuel (56,57). Normally for lightwater nuclear reactors (LWR), the 0.72% natural abundance of is enriched to 2—5% (9,58). There are special cases such as materials-testing reactors, high flux isotope reactors, compact naval reactors, or nuclear weapons where enrichment of 96—97% is used. 

Os-191 is produced by neutron irradiation of isotopically enriched 0s-190 (isotopic composition 0s-190, 97.8 o Os-188, 0.47 o Os-192, 1. 02 o). Irradiations are currrently performed at the Oak Ridge National Laboratory in the High Flux Isotope Reactor (HFIR) at a neutron flux of 2.5 x 10 n/cm -s. The routes to the various nuclides produced during irradiation of the 0s-190 target and the neutron cross-section values (2 ) are summarized below (Scheme I). 

The discovery of fermium (also einsteinium) was not the result of very carefully planned experiments, as in the cases of the other trans uranium elements, bill fermiuni and einsteinium were found in Ihe debris of an atomic weapon lest in the Pacific in November 1952. Researchers, using the Oak Ridge High Flux Isotope Reactor (HFIR) which produced 3.2-hour " Fm. determined ihe magnetic moment of the atomic ground state of the neutral fermium atom with a modified atomic beam magnetic resonance... 

Production of Transplutonium Elements in the High Flux Isotope Reactor... 

All of this would not be possible without the High Flux Isotope Reactor (HFIR) to serve as a source of neutrons to carry out the transmutation of the elements. Since first reaching full power (100 MW) on October 21, 1966, the HFIR has logged 4148 equivalent full power days through December 31, 1979, for an overall operating efficiency of 86%. During many years, this figure has run 93% or more. 

High Flux Isotope Reactor, ORNL-TM-1712 (March 1967). 

Sease, J. D. "The Fabrication of Target Elements for the High-Flux Isotope Reactor," ORNL-TM-1712 (1967). 

The neutron diffraction measurements were conducted at the High Flux Isotope Reactor of Oak Ridge National Laboratory using a triple-axis spectrometer operated in the diffractometer mode. The details of the experimental method have been described elsewhere [10,14], Slits of dimensions... 

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