E := 60*(diff(T(r, t), t)) = diff(T(r, t), r, r)+(diff(T(r, t), r))/r+r^2;

IBC := {T(r, 0) = 0, (D[1](T))(0, t) = 0, (D[1](T))(3, t) = -T(3, t)^4};

smod3 := pdsolve(E, IBC, numeric, time = t, range = 0 .. 3) ;

(thank you for answering)