That was an interesting watch, but he doesn't put a clear timeline on how long it would take. I found this article that notes that:

The Prydniprovsky Chemical Plant in the city of Kamianske in Dnipropetrovsk Oblast processed uranium ore for the Soviet nuclear program, preparing yellowcake, an intermediate step in the processing of uranium ore.

It goes on to interview a couple of engineer about what they could be expected to produce, by when, and with what level of discresion:

Robert Kelley, an engineer with over 35 years of experience in the U.S. Department of Energy's nuclear weapons complex, said that it would be possible for Ukraine to create a primitive uranium fission bomb within five years.

"It's a fairly simple thing to do in the 21st century," he told the Kyiv Independent.

It would be much more difficult for Ukraine to build a plutonium fission bomb, and it would be harder to hide, Kelley argued. It would take five to 10 years to build a plutonium reactor, he added.

In contrast with a fission bomb, a "hydrogen bomb would be incredibly complicated," Kelley said. "No way in the world would (Ukraine) be able to create it," he added.

Kelley also said that Ukraine might be able to create a crude nucleardevice without assistance from other countries. For a more complex nuclear weapon, it would have to buy technology abroad, he added.

A Russian nuclear expert and a Ukrainian nuclear expert both confirmed to the Kyiv Independent that Ukraine is capable of producing a nuclear bomb, adding that it would likely take years. The Russian expert was speaking on the condition of anonymity for fear of reprisals, and the Ukrainian expert was not authorized to talk to the press about the issue.

"Ukraine would certainly have the knowhow and resources to become a nuclear weapons state if it made the political decision to do so," Lavikainen said. "The technology required is not out of reach for many countries, and certainly not for Ukraine since it housed crucial elements of the Soviet nuclear weapons complex when it was still part of the USSR."

"Ukraine could develop both nuclear warheads and carrier vehicles since it possesses the necessary military industry, uranium deposits, and nuclearenergy sector," Lavikainen continued.

Nikolai Sokov, a senior fellow at the Vienna Center for Disarmament and Non-Proliferation, was more cautious, saying that creating a nuclear bomb "is not impossible" for Ukraine. But, it "will take years, a lot of money, and most likely external support, at least on the equipment side."

"Ukraine does not have the industrial capacity to manufacture and maintain a nuclear arsenal; it does not have fissile materials, enrichment capacity, plutonium production, most of the elements that go into a nuclear weapon capability," he added.

Liviu Horovitz, a nuclear deterrence specialist at theGerman Institute for International and Security Affairs, also said that Ukraine faces challenges if it decides to create a nuclear bomb.

"Ukraine surely has the scientific prerequisites for a nuclear weapons program," but "acquiring the necessary fissile materials is neither cheap nor fast nor very easy to do in secret," he added.

The nuclear weapons expert who spoke on condition of anonymity said that the most primitive nuclear bomb program focused on uranium centrifuges could cost around $100 million. A plutonium bomb program would cost around $1 billion, he added.