Question map
Consider the following statements: 1. Plutonium-239 can be made artificially 2. Boron is used in a nuclear reactor to absorb unwanted neutrons 3. In nature, the availability of Uranium-238 is much more than that of Uranium-235 Which of these statements is/are correct?
Explanation
Statement 1 is correct as Plutonium-239 is produced artificially in nuclear reactors by the irradiation of Uranium-238 [t1][t6]. While trace amounts exist in nature, it is primarily synthesized through neutron capture and subsequent beta decay [t5]. Statement 2 is correct because boron has a high cross-section for neutron absorption, making it an ideal material for control rods used to regulate the fission rate by absorbing unwanted neutrons [t4][t9]. Statement 3 is correct regarding natural abundance; Uranium-238 constitutes approximately 99.3% of natural uranium, whereas the fissile Uranium-235 accounts for only about 0.7% [t6][t7]. This makes U-238 roughly 140 times more abundant than U-235 in nature [t7]. Since all three statements are scientifically accurate, option 4 is the correct choice.
Sources
- [1] https://www.nrc.gov/docs/ml1122/ml11223a207.pdf