Nuclear security

North Korea nuclear reactors show new signs of activity

New satellite imagery examined by Western experts suggests North Korea has begun preliminary testing of one of its nuclear reactors at the Yongbyon research facility. The disclosure comes as preparations get underway for the summit between North Korean leader Kim Jong Un and South Korean President Moon Jae-in next month -- and ahead of Kim's planned meeting with President Trump in May.

A report by intelligence analysts Jane's says the imagery indicates the experimental light water reactor, known as an ELWR, could become operational "with little warning" as early as later this year.

According to Jane's, an image from February 25 shows an emission rising from the reactor's stack that "implies testing of the machinery at the site." The stack is "intended to vent noncondensable gases from the reactor's primary circuit," Jane's says.