The two-day Nuclear Security Summit is scheduled to be held on Monday in Washington, aiming at gathering the international community to discuss securing vulnerable nuclear materials and preventing acts of nuclear terrorism.

The discovery of nuclear power is a double-edged sword: It has brought both development and weapons to devastate human society.

The following are some major issues related to nuclear security.

In 1945, the United States successfully tested the first atomic bomb. Its power astonished the world.

In the same year, the United States dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki to end World War II, killing about 300,000 people of a total of 475,000 residents in the two cities.

After the war, the international community began to seek a ban on nuclear weapons in order to avoid future catastrophes like the ones in both Japanese cities.

In July 1957, the International Atomic Energy Agency (IAEA) was founded to inspect existing nuclear facilities and promote the peaceful use of nuclear energy.

In July 1968, the nuclear Non-Proliferation Treaty (NPT) opened for signature, calling for general and comprehensive nuclear disarmament and peaceful nuclear power for civilian use.

However, partial efforts failed as both the United States and the Soviet Union launched full-speed nuclear weapon programs during the Cold War, sparking a nuclear arms race.

After the Cold War, the United States and Russia (successor state to the former Soviet Union) have held rounds of talks on strategic disarmament and signed several treaties.

Although the two countries, in accordance with the new strategic arms reduction treaty signed in Prague on April 8, 2010, will slash their deployed nuclear weapons by a third, their arsenals still have the most nukes among other major nuclear states, including China, Britain and France.

In recent years, the nuclear issues on the Korean Peninsula and Iran's nuclear program have also been the focus of nuclear non-proliferation and disarmament agenda.

The wide use of nuclear power and terrorists gaining access to nuclear-weapon materials pose a double threat.

Although the Nuclear Suppliers Group (NSG), founded in London in 1975, has called for controlling the export and re-transfer of nuclear weapons materials, the cases of nuclear materials lost or stolen have reached 1,500 during the period of 1993 to 2008, with an increase in the smuggling of nuclear materials.

The safe use of civilian nuclear power is another problem the world has to face.

On April 26, 1986, one of the four reactors at the Ukraine's Chernobyl nuclear plant exploded, which is so far the world's worst nuclear disaster. The explosion killed 30 people on the spot, released more than eight tons of radioactive materials, contaminated 60,000 square km of land, and exposed more than 3.2 million people to radiation.

The civilian use of nuclear power has not only brought problems of nuclear security, but also of how to dispose of nuclear waste. If not properly managed, radioactive and toxic waste is extremely dangerous for humans and the environment.