How powerful is the Russian nuclear torpedo?

　　 According to the website of the US Naval Research Association, throughout history, advances in weapons and equipment have brought about tremendous changes to the military. Sometimes these shifts are structural, opening up new frontiers for warfare. For example: Aircraft carriers bring air warfare to sea, and satellites bring electronic warfare to space. Unmanned underwater vehicles will become an important equipment for future wars.
　　 The Russian Poseidon weapon system first appeared on Russian television in 2015. It is a nuclear-powered unmanned underwater vehicle capable of traveling thousands of nautical miles at a speed of about 100 knots and at a depth of 1,000 meters under the sea. While it can carry conventional weapons warheads, it can also carry 2-megaton nuclear warheads. Russia designed it as a strategic weapon to destroy enemy ports and coastal cities. It can be deployed on four Oscar II-class nuclear submarines of the Russian Pacific Fleet, and each submarine can carry up to eight Poseidon nuclear torpedoes.
　　 The Poseidon nuclear torpedo is unlike any other nuclear weapon in that it is detonated underwater and is nuclear powered. Washington called it a “new intercontinental, nuclear-armed, nuclear-powered, undersea autonomous torpedo” in its 2018 Nuclear Posture Review. Russia began seabed tests of the Poseidon nuclear torpedo in December 2018.
　　 It is hard to overstate the implications of the Poseidon nuclear torpedo, which could be deployed by 2027 and which would not be subject to the treaty in its current form. Because the weapon sails and detonates in the ocean, U.S. ballistic missile defense systems have no effect on it, and there is no way to detect a Russian launch of it. The United States will not know the threat of this weapon until it explodes.
　　 The U.S. Navy should take seriously the terrifying power of this weapon. The Norfolk Naval Base in the United States is the largest naval base in the world, with about 75 ships and 130 aircraft. A single detonation of the Poseidon nuclear torpedo in Norfolk could wipe out half of America’s aircraft carriers and about one-third of its surface ships. If the Poseidon nuclear torpedoes attack the two bases of Norfolk and San Diego at the same time, the US Navy will suffer heavy losses.