With reference to radioisotope thermoelectric generators (RTGs), consider the following statements :
- RTGs are miniature fission reactors.
- RTGs are used for powering the onboard systems of spacecrafts.
- RTGs can use Plutonium-238, which is a by-product of weapons development.
Which of the statements given above are correct ?
1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC IAS – 2024
Statement 1: “RTGs are miniature fission reactors.” This statement is incorrect. RTGs generate heat through the natural radioactive decay of a radioisotope (like Plutonium-238, Americium-241, Strontium-90), not nuclear fission (which involves splitting atoms). The heat from this decay is then converted into electricity using thermoelectric devices (based on the Seebeck effect).
Statement 2: “RTGs are used for powering the onboard systems of spacecrafts.” This statement is correct. RTGs are commonly used as power sources for spacecraft, particularly for deep-space missions (like Voyager, Cassini, Curiosity rover) where solar power is insufficient due to distance from the sun, or for missions operating in environments with limited sunlight (like lunar landers or polar rovers).
Statement 3: “RTGs can use Plutonium-238, which is a by-product of weapons development.” This statement is correct. Plutonium-238 (Pu-238) is a commonly used radioisotope in RTGs due to its appropriate half-life (about 87.7 years) and high energy density. While Pu-238 is not used in nuclear weapons, it is often produced as a by-product during the reprocessing of nuclear fuel from reactors, which can be part of the broader nuclear fuel cycle that might also produce materials for weapons. Specifically, Pu-238 is produced by irradiating neptunium-237. While not directly from weapons development, its production is linked to the nuclear industry infrastructure. The phrasing “by-product of weapons development” is somewhat imprecise but reflects the connection to the nuclear complex. Given the context of UPSC exams often presenting simplified connections, this statement is generally considered correct in this context.
Based on the analysis, statements 2 and 3 are correct, and statement 1 is incorrect.