Patent Number: 047055774
Section: abstract

A plate-shaped high power nuclear fuel element containing low enrichment uranium (5 to 20 percent by weight uranium.sup.235 in the uranium component) as fissionable material, the fuel element essentially comprising a UAl.sub.4 plate provided with an aluminum sheath or a sheath of an Al alloy and impurities inherent in the manufacturing process. A process for producing such a UAl.sub.4 plate comprises (a) intimately mixing a powder of low enrichment uranium or uranium compound U.sub.6 Fe (5 to 20 percent by weight U.sup.235) having a particle size in the range from 0.1.mu. to 90.mu. with aluminum powder having a particle size in the range from 0.1.mu. to 100.mu. in a weight ratio range of uranium to aluminum between 1.1 U:1 Al and 2.2 U:1 Al; (b) prepressing the mixture of step (a) at a pressure in the range from 300 MPa to 500 MPa and at room temperature to form a plate-shaped blank; (c) inserting the blank into an Al picture-frame or a picture-frame of an Al alloy and welding it to the frame in vacuo or inert gas argon; (d) rolling the picture-frame in three roll passes, a reduction in thickness of about 1 mm occurring in each of the first and second passes and a reduction in thickness by about 15% occurring during the third roll pass, at a temperature of 800.degree..+-.25.degree. K.; (e) inserting the plate in the frame after the third roll pass between two Mo sheets, inserting the framed plate together with the Mo sheets in a clamping device, and subsequently heat treating the plate at 800.degree..+-.25.degree. K. for a duration of at least 75 hours in order to form UAl.sub.4 in the plate.