A report published by NBC News on Monday found several American officials confirming that evidence exists that North Korea has not begun dismantling its nuclear program, instead continuing to illegally subsidize the development of nuclear weapons.

The report follows indications last week from the North Korea monitor site 38 North that development activity continues at the nation’s Yongbyon nuclear facility, which the communist regime claimed to have shut down in 2007.

NBC News cites three unnamed “senior U.S. officials” who state that American intelligence agents have witnessed the construction of new structures at a warhead storage facility and disjointed movement of warheads to different areas with seemingly no purpose other than to “confuse” international monitors trying to figure out what North Korea plans on doing with them. Officials believe the new structures exist to block visibility for satellite imaging and prevent outsiders from seeing much of the development.

According to NBC, “U.S. intelligence assesses North Korea could produce five to eight new nuclear weapons in 2018 … That pace is virtually identical to their assessment of the regime’s production of about six per year prior to the Trump-Kim summit.”

One expert – Bruce W. Bennett of the RAND Corporation – tells NBC that, since North Korea has continued to build nuclear warheads, it is likely better illegally armed today than it was before it debuted its new friendly diplomatic approach this year.

“Since the beginning of 2018, Kim has surrendered and dismantled no nuclear weapons, but has likely built five to nine new nuclear weapons. So he has not frozen his nuclear program and he has certainly not been denuclearizing; instead, he has been nuclearizing,” Bennett suggested.

The 38 North report published on Friday focuses on the Yongbyon Nuclear Scientific Research Center, which has typically been the location that Pyongyang uses to enrich uranium, develop fissile material for weapons, and experiment with nuclear reactors. It is not a bomb testing site or a missile factor.

According to the monitor site, workers at Yongbyon have engaged in extensive dredging work around the cooling system for one of the more modern reactors on the site. While emphasizing that the reason for all the dredging “remains unclear at this time,” the site notes that typical such construction to build a dam with water surrounding the reactor is to ensure that there is enough water around the plant to cool it as it generates energy. Insufficient cooling water or an inept cooling system could lead to a meltdown, an environmental disaster that would damage not just North Korea, but much of the region for decades. Episodes like the Chernobyl nuclear meltdown caused more environmental damage than the detonation of nuclear weapons, as the radioactive material seeps deep into the ground and spreads unevenly.

38 North did not speculate on an alternative explanation for the creation of a dam than the ongoing use of the facility as a nuclear energy generator. It notes that, in addition to the activity around one of the larger reactors, “a general cleanup effort seems underway” at a location they call the “experimental light water reactor.”

The site also concludes “no significant activity” found at the uranium enrichment plant on the site, which could be interpreted as a halt in the development of fissile material. The Yongbyon site is also capable of developing weapons-grade plutonium, however, rendering uranium unnecessary for any warhead project. Reports going back to 2016 signal that the Kim Jong-un regime is more interested in plutonium than uranium for development in any case.

This is far from the first report since North Korea claimed a commitment to unspecified “denuclearization” from 38 North indicating that they have not begun to shut down their nuclear program. In June, 38 North published satellite images from Yongbyon allegedly showing “improvements to the infrastructure at North Korea’s Yongbyon Nuclear Scientific Research Center are continuing at a rapid pace.”

North Korea first promised “denuclearization” in 2008. It consistently refuses to define the term as including an end to its illegal nuclear weapons program, however. On Sunday, a Russian official who personally met with Kim Jong-un told journalists that Kim said he would take no further steps to denuclearize without receiving a financial reward for the steps he has allegedly already taken, which largely consist of written statements that North Korea will eventually “denuclearize.”

North Korea has not abandoned its attempts at convincing the world that it is committed to ending its nuclear development, however. The nation celebrated the 70th anniversary of its founding on Sunday with an uncharacteristically demilitarized parade, featuring no intercontinental ballistic missiles (ICBMs) or nuclear weapons.

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