Explanation:

India’s PHWR technology is derived from a CANDU design using uranium as fuel. India already operates 18 PHWRs, each rated at either 220 MW or 540 MW, for a total installed PHWR capacity of 4.5 GW. NPCIL, meanwhile, is building four 700-MW PHWRs, two at Kakrapar Atomic Power Station in Gujarat and two at Rajasthan Atomic Power Station

Reprocessing used fuel  to recover uranium (as reprocessed uranium, or RepU) and plutonium (Pu) avoids the wastage of a valuable resource. Most of it – about 96% – is uranium, of which less than 1% is the fissile U-235 (often 0.4-0.8%); and up to 1% is plutonium. Both can be recycled as fresh fuel, saving up to 30% of the natural uranium otherwise required. The RepU is chiefly valuable for its fertile potential, being transformed into plutonium-239 which may be burned in the reactor where it is formed

There are at present 22 operational reactors, of which 14 are under the International Atomic Energy Agency (IAEA) safeguards as these use imported fuel