ISTANBUL

A North Korean nuclear complex has been undergoing "modernization and expansion" throughout this year, a recent report by a US website monitoring the reclusive state said.

"Commercial satellite imagery of North Korea's Yongbyon Nuclear Scientific Research Center from October and November 2025 shows continuation of modernization and expansion efforts throughout the site," said the report by 38 North.

"Yongbyon plays a critical role in the country's production of nuclear material for its weapons program, as the sole producer of plutonium and a significant source of enriched uranium."

The report stated that the suspected uranium enrichment site located northeast of the radiochemical laboratory has seen the most activity since the beginning of this year.

It also noted that the exterior construction of two support buildings in the eastern section of the complex is finished, and concrete paving has been added around them.

Additionally, 38 North mentioned the installation of six possible heat exchangers along the southeast side of the main building, which are used to cool centrifuges and regulate temperatures inside.

"Other equipment appears to be outside the building," the report said. "Together, these objects indicate it is likely that work to complete the interior of the main building is still underway."

On his visits to nuclear weapons-related sites, North Korean leader Kim Jong Un stressed the need to "achieve epochal successes in overfulfilling the plan for producing weapons-grade nuclear materials and in strengthening the nuclear shield of the country."

"Activity over the course of 2025 reflects these directives," 38 North said, pointing out the consistent operation of the 5 MW reactor since January and preoperational testing of the experimental light water reactor.

"These improvements all serve to help fulfill Kim's call for exponential growth of its nuclear weapons arsenals," the report added.