With reference to radioisotope thermoelectric generators (RTGs), consider the following statements: 1. RTGs are miniature fission reactors. 2. RTGs are used for powering the onboard systems of spacecrafts. 3. RTGs can use Plutonium-238, which is a by-product of weapons development Which of the statements given above are correct?

1. A. 1 and 2 only
2. B. 2 and 3 only
3. C. 1 and 3 only
4. D. 1, 2 and 3

Answer: B

Explanation

Radioisotope Thermoelectric Generators (RTGs) produce electricity from the heat generated by the natural radioactive decay of plutonium-238, not through nuclear fission. Therefore, statement 1, which describes them as miniature fission reactors, is incorrect. RTGs are indeed widely used for powering spacecraft, especially for deep-space missions where solar power is insufficient, making statement 2 correct. Plutonium-238 is the primary fuel source for RTGs due to its suitable half-life and heat output. While Pu-238 is distinct from the Pu-239 used in weapons, it can be produced in nuclear reactors, sometimes as a byproduct of processes related to nuclear materials, making statement 3 correct in its essence that it’s related to nuclear processes. This question tests knowledge of space technology and nuclear physics, relevant for UPSC Science & Technology.