Satellite imagery indicates that North Korea may be trying to restart a nuclear reactor capable of producing plutonium used in atomic weapons, a U.S. research institute said Thursday.
The analysis, released on the 38North.org - a North Korea monitoring group out of John Hopkins University - said it was too early to definitively conclude that the country has restarted its plutonium production at the Yongbyon reactor after apparently shutting it down five months ago.
Based on observations of steam being emitted from a pressure relief valve, small amounts of melted snow and the appearance of hot water draining into a nearby river, the researchers said that one possibility was that the North Koreans "are in the early stages of an effort to restart the reactor," Reuters reported.
"However, since the facility has been recently observed over a period of only a few weeks, it remains too soon to reach a definitive conclusion on this and also on whether that effort is moving forward or encountering problems," the group said.
There is a clear difference between the latest satellite imagery and the pictures from more than a year ago when the reactor was definitely operating, Reuters said.
Previous images showed foam at the end of the turbine building's steam and wastewater drainpipe, and the absence of that foam in the newest pictures could be due to the installation of new piping.
The reactor previously produced plutonium used in nuclear test explosions and was shut down in 2007 following a disarmament agreement, but reopened in 2013, according to The Independent.
Images suggest it hasn't been used since August and may be partially or completely shut down, likely for maintenance, renovation or to refuel the reactor's core, the Washington-based Institute for Science and International Security think tank said last year.
North Korea claims it is developing nuclear weapons strictly as deterrents, and has been subjected to a number of international sanctions for its repeated weapons tests.
The country said it is willing to restart international nuclear disarmament talks last held in 2008, but Washington said it must first take concrete steps to demonstrate it's commitment, Fox News reported.
Earlier this month, the North Korean government said it would halt nuclear tests if the U.S. and South Korea cancelled their annual military drills in the area. The U.S. viewed the proposal as a veiled threat, Reuters reported.
