Could Zelensky use nuclear bombs? Ukraine’s options explained

Ukraine could develop a rudimentary nuclear bomb within months if Donald Trump withdraws US military assistance, according to a briefing paper prepared for the Ukrainian Ministry of Defence.

The country would quickly be able to build a basic device from plutonium with a similar technology to the “Fat Man” bomb dropped on Nagasaki in 1945, the report states. “Creating a simple atomic bomb, as the United States did within the framework of the Manhattan Project, would not be a difficult task 80 years later,” the document reads.

With no time to build and run the large facilities required to enrich uranium, wartime Ukraine would have to rely instead on using plutonium extracted from spent fuel rods taken from Ukraine’s nuclear reactors.

Ukraine still controls nine operational reactors and has significant nuclear expertise despite having given up the world’s third largest nuclear arsenal in 1996. The report says: “The weight of reactor plutonium available to Ukraine can be estimated at seven tons … A significant nuclear weapons arsenal would require much less material … the amount of material is sufficient for hundreds of warheads with a tactical yield of several kilotons.”

Such a bomb would have about one tenth the power of Fat Man, the document’s authors conclude.

“That would be enough to destroy an entire Russian airbase or concentrated military, industrial or logistics installations. The exact nuclear yield would be unpredictable because it would use different isotopes of plutonium,” said the report’s author, Oleksii Yizhak, head of department at Ukraine’s National Institute for Strategic Studies, a government research centre that acts as an advisory body to the presidential office and the National Security and Defence Council of Ukraine.

The plutonium would need to be imploded using “a complicated conventional explosion design, which must occur with a high detonation wave velocity simultaneously around the entire surface of the plutonium sphere,” the report reads. The technology is challenging but within Ukraine’s expertise, according to the briefing.

Last month President Zelensky said he had told Trump that Ukraine would need nuclear weapons to guarantee his country’s security if it were prevented from joining Nato, as President Putin has demanded. Zelensky later said he had meant there was no alternative security guarantee, and Ukrainian officials have since denied Kyiv is considering nuclear rearmament.

The paper, which is published by the Centre for Army, Conversion and Disarmament Studies, an influential Ukrainian military think tank, has been shared with the country’s deputy defence minister and is to be presented on Wednesday at a conference likely to be attended by Ukraine’s ministers for defence and strategic industries.

It is not endorsed by the Kyiv government but sets out the legal basis under which Ukraine could withdraw from the nuclear non-proliferation treaty (NPT), the ratification of which was contingent on security guarantees given by the US, UK and Russia in the 1994 Budapest memorandum. The agreement stated that Ukraine would surrender its nuclear arsenal of 1,734 strategic warheads in exchange for the promise of protection.

“The violation of the memorandum by the nuclear-armed Russian Federation provides formal grounds for withdrawal from the NPT and moral reasons for reconsideration of the non-nuclear choice made in early 1994,” the paper states.

Russian troops are gaining momentum as they advance in the Donbas region of eastern Ukraine, and Trump has pledged to cut US military aid unless Kyiv submits to peace talks with Putin. Bryan Lanza, a Trump adviser, has already said that Ukraine will have to surrender Crimea. This week Donald Trump Jr taunted Zelensky, posting on X: “You’re 38 days from losing your allowance.”

Ukrainian forces are heavily dependent on US weaponry, and any reduction in the flow of western arms into the country, let alone a complete curtailment, would have catastrophic consequences on the battlefield. That has prompted Ukrainians to look for a way to take matters into their own hands.

“You need to understand we face an existential challenge. If the Russians take Ukraine, millions of Ukrainians will be killed under occupation,” said Valentyn Badrak, director of the centre that produced the paper. “There are millions of us who would rather face death than go to the gulags.” Badrak is from Irpin, where occupying Russians tortured and murdered civilians, and he was hunted by troops with orders to kill him.

Western experts believe it would take Ukraine at least five years to develop a nuclear weapon and a suitable carrier, but Badrak insists Ukraine is less than a year from building its own ballistic missiles. “In six months Ukraine will be able to show that it has a long-range ballistic missile capability: we will have missiles with a range of 1,000km,” Badrak said.

Hamish de Bretton-Gordon, a former commanding officer of the UK’s Joint Chemical, Biological, Radiological and Nuclear Regiment told Times Radio that Ukraine “certainly” had the technical know-how and practical wherewithal to produce a nuclear weapon.

“Trump will take note because the last thing we want is more nuclear proliferation and any sort of nuclear strike in Europe, be it from Ukrainians or the Russians,” he added.

Bretton-Gordon called Zelensky a “master strategist” who was willing to try “absolutely everything”.

Sviatoslav Yurash, a serving Ukrainian soldier and MP, told Times Radio: “At the moment it’s quite hard to talk about nuclear weaponry when we have so much other weaponry that we are asking for as far as repelling the Russian constant threats … We need to focus on the means at hand to try and protect as many lives as possible throughout this ordeal.”

Yizhak and Badrak argue that, should the US abandon Ukraine, Britain could honour its security obligation under the Budapest memorandum by helping Ukraine to develop a nuclear deterrent, given it does not have conventional means to prevent Russia from overrunning Ukraine.

Yizhak believes the threshold for developing a nuclear rearmament programme would be Putin’s troops reaching the city of Pavlohrad, a military-industrial hub about 60 miles from the present front line. Any further, and there would be a risk some of Ukraine’s largest cities, such as Dnipro and Kharkiv, could fall before the weapon was developed.

“I was surprised by the reverence the United States has for Russia’s nuclear threat. It may have cost us the war,” Yizhak said. “They treat nuclear weapons as some kind of God. So perhaps it is also time for us to pray to this God.”

“Ukraine’s foreign ministry said it had no plans to develop nuclear weapons while stressing its commitment to the NPT. “We do not possess, do not develop and do not intend to create nuclear weapons,” Heorhiy Tykhy, a spokesman for the ministry said in a statement.