Nafiz Kahraman

Friction welding of StAl and AlCu materials

Abstract The present study investigates the mechanical and metallurgical properties of friction-welded steel-aluminum and aluminium-copper bars, a friction welder having been designed and built for this purpose. The effects of the three main parameters: speed of rotation; friction load; and duration of welding; on the metallurgical and mechanical properties of the weld such as the yield, tensile and breaking strengths, are studied experimentally and statistically. The metallurgical properties of the weld are examined using electron and optical microscopy.

Investigation of neutronic performance of a peaceful nuclear explosive reactor (PACER) evaluating UF4 and ThF4 nuclides

In this study, neutronic behaviour of a peaceful nuclear explosion reactor (PACER) producing approx 1·2 GWe power from fusion explosions is analysed considering ThF4 and UF4 as fissile zones. UF4 and ThF4 are put in to the system adjacent to the inner-side of the flibe coolant zone positions (distance between explosive region and fuel zone,DR = 50, 100, 200, 400, 500 and 700 cm). Flibe percentages are taken to be 25, 50, 75 and 100%. It is found that optimum combinations of fissile zone thickness, coolant zone position and coolant percentages are 10 cm, 200 cm and 25% flibe for UF4 and 10 cm, 50 cm and 25% flibe for ThF4. The behaviour of fuels mentioned above has been observed over a period of 30 years at discrete time intervals, δt = 30 days. In the case of UF4,M values atDR = 200 cm reach 5·35, 5·22,4·88, and 4·88 from 3·12, 2·98, 2·83 and 2·83, for 25,50,75,100% flibe respectively. For ThF4 atDR = 50 cm,M values reach from 1·61, 1·54, 1·50 and 1·46 to 1·93, 2·00, 2·04 and 1·99 for 25, 50, 75, 100% flibe respectively. Cumulative fissile fuel breeding (CFFE) values reach up to 5·5 from 0·7 atDR = 200 and 25% case for UF4, and up to 6·36% from 0%, atDR = 50 and 25% flibe, for ThF4, at the end of the operation period