Simulated fuel unit

Purpose: To enable various parameter tests to be performed with variable axial generated heat distribution by disposing two electric resistance type heating elements having different generated heat distributions coaxially in a simulated cylindrical fuel rod. Constitution: First and the second strapped heating elements are wrapped at displaced pitch and at the same pitch adjacently along the vicinity of the inner periphery of a cladding tube, and the tube is filled with an insulating material so that the heating elements are steadily disposed within the tube in such a manner that the axial generated heat distributions of the first and the second heating elements are different from one another. The sectional areas of the strapped heating elements may be constant so as to flatten the heat distribution, and may be varied so as to vary the heat distribution. Thus, the axial generated heat distribution can be varied by varying the voltage applied to the respective heating elements, and various parameter tests can be performed with one simulated fuel unit. (Yoshino, Y.)