Assessment of the risk of using tactical weapons in Ukraine

How powerful are tactical nuclear weapons?

Tactical nuclear weapons have once again heated up international debate as Russian President Vladimir Putin warned Moscow would “use all available means” if its territorial integrity was threatened. US President Joe Biden criticised Putin’s nuclear warning while NATO Secretary General Jens Stoltenberg downplayed the threat, saying the Russian president “understands that a nuclear war should not be fought and cannot be won”.

Illustration: Wikimedia Commons

Tactical nuclear weapons, sometimes called non-strategic nuclear weapons, are designed to deal with large numbers of conventional forces, such as infantry and armored formations. They are smaller than strategic nuclear weapons – such as warheads mounted on intercontinental ballistic missiles.

Tactical nuclear weapons have a yield of 1 to 50 kilotons, while strategic nuclear weapons have a yield of 100 kilotons to more than 1 megaton. Tactical nuclear weapons delivery systems also have a shorter range, about 500 km, compared to strategic nuclear weapons, which are designed to be transported across continents.

The term tactical weapons is used to distinguish them from the strategic nuclear weapons that the United States, the Soviet Union, and other nuclear-armed states deploy on intercontinental ballistic missiles or from silos, submarines, and bomber fleets. While strategic nuclear weapons are subject to arms control treaties, smaller tactical weapons have never been covered by treaties.

Because tactical nuclear weapons are not much more powerful than conventional weapons, the U.S. military has reduced its reliance on them. Britain and France have eliminated their tactical arsenals entirely. Pakistan, China, India, Israel, and North Korea also have only a few of these weapons.

Russia currently maintains more tactical nuclear weapons, estimated at around 2,000, and relies heavily on them for its nuclear strategy. Russia’s tactical nuclear weapons can be deployed on ships, aircraft, and land. They are mostly deployed on air-to-surface missiles, short-range ballistic missiles, gravity bombs, tactical bombers, and anti-ship or anti-submarine torpedoes. Russia has also upgraded its systems to carry both nuclear and conventional weapons. There is growing concern about the dual capability of these systems, as Russia has deployed several short-range missile systems, notably the Iskander-M in Ukraine.

The fundamental question now is whether tactical nuclear weapons are likely to be used and whether that would risk leading to a full-scale nuclear war. While strategic nuclear weapons are losing their value as a deterrent, nuclear powers are theoretically more likely to use tactical nuclear weapons, and thus they serve to enhance a country’s nuclear deterrent. The United States has criticized Russia’s escalate-to-de-escalate strategy, whereby nuclear weapons could be used to prevent a war from spreading.

Russian tactical weapons are relatively large, with a minimum explosive yield of 10 kilotons, equivalent to 10,000 tons of TNT. Its power is two-thirds that of the 15 kiloton atomic bomb dropped on Hiroshima by the US.

“These are not small nuclear weapons,” said Daryl Kimball, executive director of the US-based Arms Control Association.

“This is going to be worse than anything we've seen since Hiroshima.”

However, if a low-yield warhead is detonated at a relatively high altitude, it will reduce the radiation from the nuclear explosion, helping to limit civilian casualties, the Royal United Services Institute (RUSI) said.

Assessment of the risk of using tactical weapons in Ukraine

Amidst the unpredictable developments of the war in Ukraine with many changes, the threat of the use of nuclear weapons has once again been raised, including tactical weapons.

The West is now concerned that Russia may use low-yield tactical nuclear weapons to advance its goals and halt Ukraine's advance. They say the scenarios for Russia's use of such weapons could vary widely. Moscow could launch a mortar shell from Ukrainian territory or a half-ton warhead from the Russian border. The targets could be a Ukrainian military base or a small city. The extent of the destruction and radiation levels would depend on factors such as the size of the weapon and the wind direction. But observers say even a small nuclear explosion could kill thousands and leave an area uninhabitable for years.

Over the past few months, computer models from the Pentagon and intelligence agencies have been trying to calculate what would happen and how the United States might respond to such a scenario. It’s not an easy task, because tactical nuclear weapons come in many different sizes and variants. The models have produced different results, depending on whether Russia’s target is a remote Ukrainian military base, a small city, or a “show of force” explosion over the Black Sea.

While much remains unknown about Russia’s tactical arsenal, it varies in size and power. The weapon that Europe is most concerned about is the heavy warhead mounted on the Iskander-M missile, which can reach cities in Western Europe.

Russia's short-range Iskander-K cruise missile can carry nuclear warheads hundreds of kilometers away. Photo: AP

One question that Western observers are interested in right now is whether Russia will actually use tactical nuclear weapons?

Last week, the Institute for the Study of War said that “Russia’s use of nuclear weapons is a huge gamble with limited payoffs and would not achieve Moscow’s stated objectives. However, the Kremlin would likely use nuclear weapons to freeze the fighting in order to consolidate its current positions and protect its gains.” Even so, the think tank concluded, that would require “multiple tactical nuclear weapons.”

The US has warned that it would respond strongly to any such move, but has not specified what response measures it would take. Ben Hodges, former commander of the US Army in Europe, said the US would not respond with a nuclear strike but would destroy Russia’s Black Sea Fleet or bases in Crimea. That would mean a direct conflict between Russia and the US, increasing the risk of nuclear war between the two countries.

However, so far, the US has been very careful to avoid direct conflict with Russia..

“When nuclear weapons are used, even in a limited way, there is no guarantee that the two sides can control the use of nuclear weapons, and there is no guarantee that it will not quickly escalate into a full-blown nuclear disaster,” said Kimball.

A source close to the US Department of Defense predicted that if Russia uses tactical nuclear weapons, Moscow would likely choose a military target in Ukraine to attack in a show of force.

Meanwhile, on October 2, British Defense Secretary Ben Wallace said that Russia's use of nuclear weapons "is highly unlikely"./.

Kieu Anh