Consider a nuclear fuel element of spherical form, consisting of a sphere of “fissionable” material.

Consider a nuclear fuel part of round construct, consisting of a vocation of "fissionable" embodied wrapt by a round shell of aluminum "cladding" as shown in Fig. P3.22. Nuclear fission is a rise of affectionate soul, which varies nonuniformly from the character of the vocation to the interface of the fuel part and the cladding. We eagerness to designate the region arrangement in the nuclear fuel part and the aluminum cladding. The predominant equations for the two regions are the same, after a while the qualification that there is no ebullition rise order for the aluminum cladding. We have

where subscripts 1 and 2 relate to the nuclear fuel part and cladding, respectively. The ebullition stock in the nuclear fuel part is assumed to be of the construct

where qo and c are constants depending on the nuclear embodied. The word provisions are

Use two rectirectilinear parts to designate the bounded part solution for the region arrangement, and collate the nodal regions after a while the proper solution