Behind the IAEA briefing on Iran: safeguards, the NPT and what diversion means

Background

The IAEA told the UN Security Council that it cannot confirm that none of Iran's safeguarded nuclear material has been diverted; this item explains the words in that finding.
Safeguards are the checks the International Atomic Energy Agency applies to nuclear material a country has declared, to see that it stays in civilian use.
Diversion means that declared material has been taken away from that declared, civilian purpose.
The checks rest on the Treaty on the Non-Proliferation of Nuclear Weapons, the NPT, under which a non-nuclear-weapon state accepts agency verification.
Verification needs inspectors on the site; the agency has said plainly that satellite monitoring cannot replace them.
The IAEA has its headquarters in Vienna and is led by a Director General, Rafael Grossi.
Its Board of Governors takes the agency's decisions between General Conferences, and can send a non-compliance finding to the Security Council.