WASHINGTON (AP) - A U.S. research institute says North Korea may have temporarily shut down a plutonium reactor earlier this year as it grappled with water supply problems that could threaten the safety of its nuclear complex.
The North restarted the reactor at the Nyongbyon (nee-YUHNG'-bee-yuhn) complex only last summer, backtracking on a commitment of previous aid-for-disarmament negotiations.
A constant water supply from a nearby river is essential to cool the reactor and another reactor under construction.
U.S.-Korea Institute says satellite imagery show the recently restarted reactor may have been temporarily shut down or operated at a lower power level for repairs after flooding caused the river to change course.
The reactor appears to have been operating again by mid-February.
The findings are being published Monday on the institute's website, 38 North.