UPSC CSE Prelims
Question 63
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 ?
View correct answer and explanation
Correct answer: B
Correct Option: B (2 and 3 only)
Explanation: Radioisotope thermoelectric generators convert heat released by radioactive decay into electricity without a fission chain reaction; Pu-238 can supply the heat for spacecraft.
Statement / Pair / Item-wise Analysis:
1. Incorrect/False - An RTG uses spontaneous isotope decay, not controlled fission like a reactor.
2. Correct/True - RTGs power instruments and systems on deep-space missions.
3. Correct/True - Pu-238 can be produced from nuclear-material streams linked to weapons-related reactor programmes; it is a heat source rather than weapons-grade Pu-239.
Option-wise Analysis:
A. Incorrect-incorrectly includes 1 (An RTG uses spontaneous isotope decay, not controlled fission like a reactor.); omits correct item 3 (Pu-238 can be produced from nuclear-material streams linked to weapons-related reactor programmes; it is a heat source rather than weapons-grade Pu-239.).
B. Correct-includes precisely the true/correct statements or pairs identified above.
C. Incorrect-incorrectly includes 1 (An RTG uses spontaneous isotope decay, not controlled fission like a reactor.); omits correct item 2 (RTGs power instruments and systems on deep-space missions.).
D. Incorrect-incorrectly includes 1 (An RTG uses spontaneous isotope decay, not controlled fission like a reactor.).
Review note: Pu-238 is not ordinarily a direct by-product of a nuclear weapon; the statement is interpreted as a material linked to weapons-programme production chains.