Enrichment of nuclear fuel 2 points A. increases the relative concentration of uranium-235 to 3-20% to produce energy in a power plant. B. increases the relative concentration of uranium-235 to 30-50% to avoid a nuclear explosion at higher percentages. C. increases the relative concentration of uranium-235 from 60% to 90% to achieve maximum electricity generation D. decreases the relative concentration of uranium-235 from 100% to 30-50% to avoid a nuclear explosion at higher percentages.

B. increases the relative concentration of uranium-235 to 30-50% to avoid a nuclear explosion at higher percentages.

Explanation:

Uranium enrichment may be defined as a process which is necessary for creating effective nuclear fuel from the mined uranium by mainly increasing the percentage of the uranium-235 that undergoes fission with a thermal neutrons.

The enrichment process removes the unwanted uranium-238, thus making uranium 235 concentration higher. It takes up much work to increase the relative concentration of the uranium 235 to make it 30% to 50% so as to avoid a nuclear explosion at such higher percentages.

- decrease the number of plants and animals living in the water.