An analysis of recent satellite images indicates North Korea earlier this year temporarily halted operations at its plutonium reactor, likely due to safety fears.
The North is assessed to have restarted its Soviet-era graphite reactor at the Yongbyon complex in 2013 in accordance with its vow to rededicate nuclear facilities toward the production of fissile material for weapons production.
However, the expert website 38 North in a Monday image analysis concluded that operations at the reactor might have either been temporarily suspended or greatly reduced in recent months to permit maintenance work necessitated by recent flooding, the Associated Press reported.
An uninterrupted stream of water from the river is used to cool the graphite reactor. The July 2013 flood caused the principal channel of the Kuryong River to divert away from the reactor's water supply and potentially damaged pipes that had been laid on the river bottom, said the analysis by 38 North, a project of the U.S.-Korea Institute at Johns Hopkins University.
Between December and February, the North appears to have quickly finished "major water channel excavations and dam construction," wrote 38 North image expert Nick Hansen. The reactor seems to have started operating again by mid-February.
The Kuryong River supplies cooling water to both the graphite reactor and a newer, experimental light-water reactor that is almost completed, according to 38 North.
"Despite these short-term fixes, the danger posed by an unreliable supply of water for the Yongbyon reactors remains, particularly since the channels and dam constructed are made from sand and could be washed away by future floods," Hansen wrote.
A number of international nuclear specialists have raised concerns about a possible reactor meltdown at Yongbyon given North Korea's relative inexperience with reactors and the country's international isolation and poverty.
"These recent problems should be a wake-up call for Northeast Asia," 38 North editor Joel Wit said to AP.
This article was published in Global Security Newswire, which is produced independently by National Journal Group under contract with the Nuclear Threat Initiative. NTI is a nonprofit, nonpartisan group working to reduce global threats from nuclear, biological, and chemical weapons.