MEASUREMENT OF F$sup 18$ ACTIVATION IN THE CORE OF A WATER-COOLED REACTOR

The fluorine activity in the ASTRA Reactor, generated at a given fast neutron flux by the nuclear reaction O/sup 18/(p n)F/sup 18/ was determined. The fluoride activity was measured both before chemical removal of all perturbing activities and after chemical separation. In contrast to the F/sup 18/ initial activity determined by chemical separation, the contribution of Na/sup 24/ to the 0.51-Mev line must be corrected in the purely physical measurement. The F/sup 18/ activity measured without chemical separation with the deductron of the correction factor and the F/sup 18/ activity before chemical separation show variations up plus or minus 5%. The measurement of the absolute neutron flux and the flux distribution was carried out by the S/sup 32/ (n,p)P/sup 32/ nuclear reaction, the mean saturation activity per ml of solution at a point uistributed over the complete fuel zone of the standard elements was determined, and the activation of F/sup 18/ was determined in dependence on the fast neutron flux. The saturation activity per ml of solution, at a fast neutron flux of 10/sup 11/ n/cm/sup 2/ sec, is 0.29 x 10/sup -8/ C. The limits of error in the determination of the F/sup 18/ initiai activity is plus ormore » minus 10%. (tr-auth)« less