The present study indicates that the estimation of the gamma-ray strength function is the approach least subject to error when unmeasured capture cross sections are to be computed. An estimate is given for the /sup 88/..gamma..(n,..gamma..) cross section.

Experimental and theoretical research on production of negative ion beams is described. Results from a double charge-exchange experiment include 10 ms pulses of 100 ma of D/sup -/ accelerated to 60 kV. Equilibrium fractions of D/sup -/ in several metal vapors are presented. Mechanisms and measurements of D/sup -/ on surfaces are described, and a scheme is shown for producing high current, high energy beams originating on surfaces.

The effect of introducing a neutron and gamma shield into the annulus between the reactor vessel and the shield tank is analyzed. This addition has been proposed in order to intercept neutron streaming up the annulus during nuclear operations. Its installation will require removal of approximately 20-/sup 1///sub 2/ inches of stainless steel foil insulation at the top of the annulus. The resulting conduction path is believed to result in increased water temperatures within the shield tank, possibly beyond the 150/sup 0/F limit, and/or cooling of the reactor vessel nozzles such that adverse thermal stresses would be generated. A two dimensional thermal analysis using the finite element code COUPLE/MOD2 was done for the shield tank system illustrated in the figure (1). The reactor was assumed to be at full power, 55 MW (th), with a loop flow rate of 2.15 x 10/sup 6/ lbm/hr (268.4 kg/s) at 2250 psi (15.51 MPa). Calculations indicate a steady state shield tank water temperature of 140/sup 0/F (60/sup 0/C). This is below the 150/sup 0/F (65.56/sup 0/C) limit. Also, no significant changes in thermal gradients within the nozzle or reactor vessel wall are generated. A spacer between the gamma shield and the shield tank …