invertor welding transformer turns calculation

i want to design welding invertor machine for 200 ampere.i am using uc3844 ic with 5o% duty cycle and frequency is 50khz.i have ferrite u type core with 35*35 mm rib.the height of core is 200mm.i will use copper winding wire for primary and secondary will be stip wire.

please give me the turns for the same.the dc voltage is 320 volts from bridge rectifiers.