देश के सीमित घरेलू यूरेनियम भंडारों की समस्या से निपटने के लिए मूल रूप से किसने भारत के तीन चरणों वाले परमाणु ऊर्जा कार्यक्रम की परिकल्पना की थी?

What is the reactor design type of TAPS Units 1 and 2, India's first nuclear power reactors?

With reference to the Prototype Fast Breeder Reactor, consider the following statements: I. Fast breeder reactors primarily rely on slow (thermal) neutrons moderated by heavy water to sustain the chain reaction. II. In breeder reactors, fertile isotopes such as Uranium-238 can be converted into fissile material through neutron absorption. III. Liquid sodium is used as a coolant in fast breeder reactors because it efficiently transfers heat without significantly slowing down neutrons. IV. Attainment of 'criticality' in a nuclear reactor implies that neutron production and neutron losses are in equilibrium, enabling a self-sustaining chain reaction. How many of the statements given above are correct?