The American administration wants agreement from North Korea to inspections by the International Atomic Energy Agency of sites where it is suspected of keeping material for nuclear weapons.
Before that some of Mr Kim's nuclear material had turned up in Libya, via the nuclear black market, before that country handed in all its bomb-making paraphernalia.
Iran told the agency that no nuclear material had been introduced into the plant, and enrichment levels would only be high enough to make nuclear fuel, not a bomb.
When inspectors found suspicious nuclear material at this site, the Iranians said it was just contamination.
He said multiple mechanisms existed to prevent the theft or loss of nuclear material.
Food inspectors, air-traffic controllers, specialists who track down loose nuclear material wouldn't get their paychecks.
Among its endeavors, the agency tries to verify that countries correctly and completely account for their nuclear material and activities.
And we're going to get the job of containing all of that nuclear material in Russia done in four years.
It has verified that none of the nuclear material that Iran has already declared has been diverted for a weapons programme.
And chemists who understand how plutonium ages also develop forensics to track missing nuclear material and catch those trafficking in it.
Senator Kennedy also revisited the infamous (and somewhat irrelevant) question of whether Saddam Hussein was pursuing the acquisition of nuclear material from Africa.
In the absence of new production, old weapons must be repaired and upgraded, often using nuclear material recovered from weapons that are being retired.
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Iran denies it is trying to build a nuclear weapon and has taken steps in recent months to reduce its stores of high-level nuclear material.
In spite of international concerns, the U.S. government has said it believes Pakistan's assurances that its nuclear material will not get into the wrong hands.
Instead, NASA imbeds a nuclear material in a radioisotope thermal generator.
If disaster strikes and a LFTR springs a leak, the spill cools to an inert lump of rock, chemically locking all the nuclear material inside.
China declared its support for steps to stop illicit trafficking of nuclear material in what correspondents describe as an uncharacteristically prompt response to a US initiative.
The U.S. and its allies are seeking to gain Iran's willingness to suspend its production of near weapons-grade nuclear material at its uranium-enrichment sites in return for economic incentives.
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The fourth mistake was that the company had insisted all along that, because the amount of nuclear material would always be carefully weighed and therefore controlled, there was no chance of criticality ever occurring.
And it's a testament I think to that well-defined agenda that two years later we're seeing all these deliverables take place that are taking a whole bunch of nuclear material out of vulnerable positions that could fall into the wrong hands.
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But, in effect, off-shore, outside of Iran, so that this would satisfy the concerns of others like the United States and the Europeans that Iran couldn't secretly use this process to create a stash of what's called fissile material for a nuclear weapon.
You see you only have to declare within the Safeguards Agreement a nuclear facility, ok, this is an important thing, you have to underline it, that you only declare a nuclear facility a hundred and eighty days before you introduce the nuclear material into that.
But the most important thing about that story, which is not often told, is that as a result after the Cuban missile crisis, immediate steps were taken to correct our inability to collect on the movement of nuclear material out of the Soviet Union to other places.
And then we return here to focus, as I mentioned, with 46 other countries, on locking down any vulnerable nuclear material over the course of the next four years to ensure that we are not faced with that kind of material falling into the hands of a terrorist organization.
"In this day and age, no one should be allowed to possess nuclear-weapons-usable material without providing an armed defense of that material, " said Edwin Lyman, a nuclear physicist with the Union of Concerned Scientists.
Uranium 235 is the key material in starting a nuclear reaction, and its acquisition is the main problem facing states which want to go nuclear.
Russia also continues to manufacture nuclear arms and material and to develop new classes of strategic delivery systems.
The material was used in a nuclear power experiment at Dounreay later abandoned following the discovery of oil and gas in the North Sea.
The United States would hold North Korea "fully accountable for the consequences" if the secretive state were to provide nuclear weapons or material to other nations or groups, Gates warned.
The resolution bars North Korea from exporting a wide range of weaponry, and "calls upon" all U.N. states to search North Korean vessels, with their consent, for nuclear-related material and other contraband.
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