"If (the DPRK is) moving toward the development of a light- water nuclear reactor, it goes against expectations of six-party nations or the international community," Seoul's foreign ministry spokesman Kim Young-sun told reporters in a press briefing.
Though the DPRK has repeatedly announced it would develop a light-water nuclear reactor using its own nuclear fuel, South Korea has yet to assess how capable the country is in building such a reactor, Kim added.
The DPRK's official news agency KCNA has said in a commentary in March that the country would build a light water reactor with its own nuclear fuel in 2010s in response to "a black propaganda campaign" from its enemies. The news agency saw attempts from the United States, South Korea and Japan to discourage foreign investment in the DPRK by portraying a bleak picture of the DPRK economy.
The remarks comes after Japan's Kyodo News Agency reported Pyongyang is building an experimental light-water reactor at its Yongbyon nuclear facility, citing Siegfried Hecker, a U.S. nuclear expert who recently traveled to the DPRK.
Recent satellite images of the Yongbyon complex also showed what seemed to be new activity there. The DPRK froze the site under the six-party talks, currently stalled due to its unilateral withdrawal in April 2009.
While light-water reactors are usually for civilian purposes, they use enriched uranium as fuel. And highly enriched uranium can be used in producing atomic bombs.
The United States and other countries planned to give Pyongyang two 1,000-megawatt light-water reactors under a 1994 deal aimed at stopping the DPRK's nuclear program, but the plan later fell through as Washington accused Pyongyang for pursuing a uranium enrichment program.