Jonathan Ernst / Reuters
North Korea has continued to upgrade its only known nuclear reactor, satellite imagery has shown, calling into question the value of the summit agreement between Donald Trump and Kim Jong Un. Infrastructure improvements at the Yongbyon nuclear plant, which is used to fuel the country’s weapons program, are “continuing at a rapid pace,” according to analysis by monitoring group 38 North. The upgrades include the modification of a cooling system for the plutonium production reactor, at least two new non-industrial buildings, and a new engineering office building. Kim Jong Un committed to “complete denuclearization” in a meeting with Trump in Singapore this month, but the details of how and when that will happen were not explicitly set out. “Infrastructure improvements continue at Yongbyon,” Jenny Town, managing editor of 38 North, wrote on Twitter. “Underscores reason why an actual deal is necessary, not just a statement of lofty goals.”