In India, why are some nuclear reactors kept under “IAEA safeguards” while others are not ?

The correct option is: "Some use imported uranium and others use domestic supplies"

Here is a detailed, step-by-step explanation of why this is the correct answer:

1. Understanding the IAEA Safeguards:
The International Atomic Energy Agency (IAEA) is an international organization that seeks to promote the peaceful use of nuclear energy and to prevent its use for any military purpose, including nuclear weapons. Countries that sign safeguards agreements with the IAEA agree to allow inspectors to verify that nuclear material and facilities are used only for peaceful purposes.

2. India's Unique Nuclear Position:
India is not a signatory to the Nuclear Non-Proliferation Treaty (NPT) as a non-nuclear-weapon state, but it has a specific safeguards agreement with the IAEA. Under the Indo-US Civil Nuclear Deal (officially known as the 123 Agreement) finalized in 2008, India agreed to separate its civilian and military nuclear facilities.

3. The Distinction Between Protected and Unsafeguarded Reactors:
To facilitate international nuclear trade, India separated its nuclear power plants into two categories:
• Safeguarded Reactors: These are civilian nuclear reactors that use imported uranium/fuel. Because international suppliers (like Russia, France, Kazakhstan, etc.) export uranium under the condition that it must only be used for peaceful purposes, these facilities must be placed under IAEA safeguards for monitoring.
• Unsafeguarded Reactors: These are reactors that rely entirely on domestic (locally mined) uranium or are part of India's strategic/military program. Since India does not import fuel for these reactors from foreign suppliers, it is not legally obligated to place them under international monitoring, allowing the country flexibility for national defense needs.

4. Analyzing Other Options:
• Some use uranium and others use thorium: While India has a three-stage nuclear program aimed at using thorium, the safeguard distinction is currently based on the source of the fuel (imported vs. domestic) rather than the uranium vs. thorium distinction.
• Some are operated by foreign enterprises and others are operated by domestic enterprises: In India, all nuclear power plants are operated by public sector undertakings (like Nuclear Power Corporation of India Limited - NPCIL) and not by foreign enterprises.
• Some are State-owned and others are privately-owned: Currently, nuclear power generation in India is under complete state control, so private ownership is not the dividing factor.