Fresh evidence has surfaced to shore up speculation that North Korea has restarted a nuclear reactor to produce plutonium for bombs, a US think tank said Thursday.
Satellite photos from Sept. 19 showed hot waste water being discharged into the nearby Guryong River from a recently installed drainpipe that is part of a new cooling system at the Yongbyon nuclear complex.
This indicates that "the reactor is in operation and the turbine-powered electrical generators are producing power," said Nick Hansen of the US-Korea Institute at Johns Hopkins School of Advanced International Studies on its website, 38 North.
The findings are the latest in a string of signs that the communist state has put its 5-megawatt graphite-moderated reactor back online, possibly to use as a bargaining chip in disarmament-for-aid negotiations with Washington.
In April, Pyongyang announced that it would reactivate the reactor that was shuttered and disabled under a 2007 six-party agreement involving the South, the US, China, Japan and Russia. The decision coincided with the North's adoption of the so-called parallel pursuit of nuclear and economic development.
The Washington-based institute earlier studied satellite imagery from late August which showed steam coming out of a generator building at the complex, suggesting the reactivation process was in full swing. The Institute for Science and International Security said in August that the North had doubled the size of the Yongbyon plant, citing other aerial photos.
The nuclear reactor generates electricity by heating water until it becomes high-pressure steam that in turn is piped to a turbine and spins it, SAIS explained. The steam cools after passing through the turbine and condenses into hot waste water that must be removed from the turbine building. It is pumped into the drainpipe and when the hot water reaches the river bank it produces white foam at the end of the drainpipe.
South Korea has said the moves would constitute "a serious situation" and "breach of past agreements and UN Security Council resolutions."