Optimization design research for 89Sr production in China Experimental Fast Reactor.
As the first sodium cooled fast reactor in China, China Experimental Fast Reactor (CEFR) has many characteristics, such as high power rating, high neutron flux and high neutron leakage as its hard spectrum. These leakage neutrons can be used to produce 89Sr by fast neutrons (n, p) reaction. By means of some special designs, including designing optimized target assembly, choosing reasonable irradiation location and appropriate irradiation cycle length, in order to improve specific activity of 89Sr. The MNCP code was used to the calculations coupled ORIGRN2 procedure. The higher activity of 89Sr can be obtained by these optimization designs, so it is feasible to produce 89Sr in the fuel region of CEFR.
89Sr production in fast reactors
ConclusionsIn summary, we have proposed a new method for producing89Sr for medical purposes from natural yttrium according to the reaction (n, p) in fast-neutron reactors. Investigations confirm the computational parameters of the production: from 2 to 15 mCi89Sr per gram of the starting yttrium. We have shown that90Sr can be extracted and the final product with the required radionuclide purity can be obtained. Commercial production of89Sr in BR-10 and BOR-60 has now started.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.