Light weight radioisotope (LWR) 89Sr and 90Sr could be obtained from used rods in fission atomic plants. The economics of the disposal of nuclear bars indicate the convenience to develop added value applications. The difference in t1/2 allows 89Sr to deliver its energy at a rate 200 times higher than 90Sr. A large emission number of low penetrating power particles in a short time characterize 89Sr, which allows that these highly radioactive LWR involves a rather limited danger. Chemical similitude of calcium and strontium uptake has led to the use of 89Sr in treatment of bone cancer metastasis. 89Sr damages animal tissues because ionize water, but penetrates through the skin about: 5 to 8 mm. Hence, to obtain it in insoluble form, like obtaining 89Sr silicate, could make possible its wider use. Purifying 89Sr from contaminant 90Sr allows that after one year do not leave any contamination. LWR could be covered with scintillators substances, which by subtracting kinetic energy from beta-radiation, emit light and function as a major source of shielding. This treatment engineers Radioisotope Light Generators (RLG). Their light could activate photovoltaic cells (PV), which could lead to nano-devices without moving parts RLG-PV.