Radioactivity Detected After N.Korea Nuclear Fusion Claim

Right after North Korea claimed a successful nuclear fusion test on May 12, the northernmost radiation detection station of the [South] Korea Institute of Nuclear Safety detected an eightfold increase in the radioactive substance xenon, it emerged Sunday.

Since nuclear fusion is the core process in hydrogen bombs, there is speculation that the North actually ran a small-scale nuclear test to develop the technology at the time.

On May 14, two days after the North's announcement, air analysis of KINS's radiation detection station in Geojin, Gangwon Province showed about eight times as much xenon as in ordinary times, a government official said. "Authorities concerned have concentrated on analyzing this," he added.

Like krypton, xenon is a gaseous radioactive matter that is produced as a result of nuclear fission. It is regarded as the surest proof of a nuclear test because it does not interact chemically with other matters.

Seoul detected increased concentrations of xenon a few days after Pyongyang conducted a nuclear test in North Hamgyong Province in 2006.

A nuclear expert said fusion technology normally uses magnetic fields or laser beams to compress tritium. "But an atomic bomb is used to compress the tritium in hydrogen bombs. If xenon was detected, it must have been produced in such a process."

But Seoul is skeptical about the veracity of Pyongyang's announcement, saying the North doesn't have the expensive test reactor needed for nuclear fusion, and the claim that it has succeeded in creating a nuclear fusion reaction for power generation is implausible since no country has yet managed to put fusion-based power generation to commercial use.

But the government has kept the lid on the KINS's detection of xenon or the result of its analysis. "Xenon can be detected as a result of a nuclear test as well as of the operation of a power plant," the official said.

The North's official Rodong Sinmun daily on May 12 claimed scientists "succeeded in a nuclear fusion test with the country's own technology."

Hwang Jang-yop (87), a former secretary of the North Korean Workers' Party who defected to the South in 1997, said, "The North has studied making hydrogen bombs from the beginning. A successful nuclear fusion test is a possibility."

englishnews@chosun.com / Jun. 21, 2010 11:56 KST