Explainer: What are tactical nuclear weapons and why is Russia holding exercises?

By Mark Trevelyan

LONDON (Reuters) – Russia and its ally Belarus are conducting exercises to practice deploying tactical nuclear weapons.

What are these weapons, how can they be used and what do we know about the exercises?

WHAT ARE TACTICAL NUCLEAR WEAPONS AND HOW POWERFUL ARE THEY?

Tactical nuclear weapons are intended for use on the battlefield, as opposed to strategic weapons designed to be fired over vast distances to wipe out enemy cities. The underlying physics is the same, using nuclear fission and fusion reactions to release large amounts of energy. The destructive power of tactical nuclear weapons, although generally less than that of strategic weapons, is nevertheless comparable to that of the atomic bombs used by the United States to destroy the Japanese cities of Hiroshima and Nagasaki at the end of World War II. worldwide.

HOW MUCH DO RUSSIA AND THE UNITED STATES HAVE?

The United States has about 200, half of which are on bases in Europe. Russia has about 1,558 non-strategic nuclear warheads, experts from the Federation of American Scientists estimated in March. These could be launched by different means, including being dropped as bombs or installed on various missiles capable of carrying nuclear or conventional warheads.

WHAT DO RUSSIAN EXERCISES LOOK LIKE?

Russia said the first phase, conducted last month, involved the Kinzhal and Iskander missiles. It took place in the southern region of Akhtubinsk, according to the geolocation confirmed by Reuters. A video released by the Defense Ministry showed convoys of vehicles carrying Iskanders and presumably the nuclear warheads intended to be installed on them. The warheads were blurry in the video. It also showed a Tu-22M Backfire bomber and a MiG-31K fighter, both capable of carrying the hypersonic Kinzhal. On Tuesday, video of the second phase showed an Iskander system rammed into a field and the missiles moved into position, along with MiG-31 supersonic interceptors and Tupolev Tu-22M3 long-range supersonic bombers.

WHY IS RUSSIA HOLDING THE EXERCISES?

Russia says such exercises are normal practice but were necessitated by what it sees as hostile actions by the United States and its European allies. Moscow said last month it hoped the exercises would calm “hotheads” in Western capitals, after French President Emmanuel Macron raised the possibility of sending European troops to fight with Ukraine against Russia and that British Foreign Secretary David Cameron said Kiev was free to use Western troops. weapons against targets on Russian territory. Western nuclear experts say Russia is sending a signal aimed at dissuading NATO from becoming more deeply involved in the war in Ukraine.

WHAT WOULD BE THE PURPOSE OF USING A TACTICAL NUCLEAR WEAPON?

Experts say it would not be a matter of seizing territory, because using such a weapon would create a poisonous radioactive desert. Instead, some believe Russia could use one in a scenario where its troops are in retreat and facing a major defeat. In a January report for the International Institute for Strategic Studies, William Alberque, a former Pentagon and NATO official, said Russia could consider using a non-strategic nuclear weapon (NSNW) to “sober up » the West and force it to resolve a conflict on the territory of Moscow. terms, calculating that the United States would not be willing to cross the nuclear threshold in retaliation. President Vladimir Putin said last week that Russia would be able to achieve victory in Ukraine without resorting to nuclear weapons.

HOW WILL WE KNOW IF A TACTICAL NUCLEAR WEAPON HAS BEEN USED?

Experts say preparations for a launch would likely be visible to Western military intelligence satellites because it would involve the type of steps seen in exercises, including moving nuclear warheads from a central storage facility. These would take place over several hours, with Russian command and control centers placed on high alert.

From the perspective of Russia's adversary, incoming missiles carrying tactical nuclear warheads would be indistinguishable from the types of missiles with conventional nuclear warheads that Russia has been firing at Ukraine for more than two years. But a real nuclear strike would be clearly identifiable by the scale of the destruction, the seismic shock and the massive emission of radiation.

(Reporting by Mark Trevelyan; editing by Guy Faulconbridge and Ros Russell)