Match LIST-I with LIST-II LIST-I (Nuclear Fuel cycle Processes) LIST-II (Their…

Concept. The nuclear fuel cycle is the ordered chain of operations that carries uranium from the ground, through a reactor, and finally to permanent isolation. Each stage is identified by the characteristic material associated with it — for the front-end stages, the substance that leaves the stage; for the terminal back-end stage, the substance it receives and takes charge of. The front end progressively upgrades uranium first in chemical concentration and then in isotopic composition, while the back end deals only with material that has already been irradiated. So a matching item of this kind is solved by asking, for each named process, which material belongs to it.

Application to this item.

1. Mining is the extraction stage: uranium-bearing rock is taken from open-pit, underground or in-situ-leach deposits. What leaves the mine is raw uranium ore, typically well under one percent U3O8 by mass.

2. Milling is the concentration stage: the ore is crushed, ground and leached with acid or alkali, and the dissolved uranium is precipitated and dried into a concentrate of roughly 70–90% U3O8. This yellow-toned powder is the yellow cake of the trade (printed in the original question paper as “Yellow coke”).

3. Enrichment is the isotope-separation stage: after conversion of the concentrate to uranium hexafluoride, centrifuges raise the 235U content from its natural 0.7% to about 3–5%. The output is reactor grade uranium, the only form of the element that will sustain a chain reaction in an ordinary light-water reactor.

4. Disposal is the terminal back-end stage, and the material that belongs to it is the spent fuels: the irradiated assemblies discharged from the reactor core are cooled in ponds, held in interim storage and ultimately consigned to a deep geological repository, or in a closed cycle sent for reprocessing first. Note that disposal receives this material rather than producing it — LIST-II pairs each process with the material that characterises it, not strictly with an output.

So the pairing is A–III, B–IV, C–II, D–I:

Cross-check. Two structural constraints confirm the pairing without recalling any single fact:

• The front end runs in a fixed order — mine, mill, convert, enrich, fabricate — so the material becomes purer at every step. Ore must therefore precede yellow cake, and yellow cake must precede reactor grade uranium; no pairing that inverts that sequence can survive.

• Spent fuel exists only after irradiation, so it cannot be the product of any front-end process; it can attach only to the back-end stage, which here is disposal. Fixing that one anchor forces the remaining three pairings uniquely.

Note on terminology. “Yellow coke” as printed in the original question paper is a typographical slip for yellowcake, the standard name for the U3O8 concentrate produced by milling; coke is an unrelated carbon product. The stem above has been corrected to “Yellow cake”.