Spotlight On Nuclear Nations

North Korea boasted on Monday that it successfully tested a nuclear weapon, sparking a barrage of global condemnation over an underground blast that appeared to thrust the volatile communist state into the elite club of nuclear-armed nations.

The explosion prompted worldwide concerns that it could seriously destabilize the region, and even Pyongyang's ally China said it strongly opposed the move

How Many Nuclear Nations Are There?

The 1968 nuclear Non-Proliferation Treaty recognizes Nuclear Weapons States as countries which have created and detonated a "nuclear weapon or other explosive device" prior to Jan. 1, 1967. There are five NWS nations: U.S., Russia, China, United Kingdom and France.

Three countries — Israel, India and Pakistan — are not part of the NPT, but are considered holders of nuclear weapons technology.

What Is The Background On North Korea's Threat

Even before this latest threat, the North Korean nuclear crisis has been growing over sharp rhetoric and bold moves by the communist nation in recent years, and has led to increased tensions between the North and South Korea, Japan and the United States. The diplomatic standoff has raised fears of another nuclear crisis on the Korean Peninsula like one in 1994 that some say nearly led to war.

Why Is North Korea A Threat?

Since the latest nuclear tensions erupted, North Korea has become the first country to withdraw from the nuclear Non-Proliferation Treaty and has reactivated a 5-megawatt nuclear reactor at Yongbyon. Not only does this facility produce raw materials that could be used for atomic weapons, but Pyongyang also claims to have reprocessed 8,000 spent nuclear fuel rods that had been in storage since 1994. If that's true, they would provide North Korea with enough plutonium to build six to eight nuclear weapons, in addition to the one or two it is believed to have at present.

What Are The Effects Of A Nuclear Bomb?

Since their development in the 1940s, nuclear weapons have long been feared for their incredibly destructive and deadly power. It is difficult to project exactly the outcome of a nuclear detonation because of the many variables associated with dropping such a bomb. But the results would definitely be of disastrous proportions. A report published by the U.S. Congress' Office of Technology Assessment (OTA) in 1979 outlined the basic expected result of various nuclear bomb scenarios in differently populated areas and you can read it here.

To learn more about nuclear weapons:

• Follow recent events and learn about this secretive nation's nuclear capabilities, click here.

• Click here to read about the dangers of potential dangers to humans in the nuclear age.

• Click here for an interactive from CBSNews.com about the world's nuclear weapons powers, missile defense and a history of the nuclear weapons age.