How does Trident compare to the Hiroshima bomb? Food for thought!

Posted: 5th August 2015

As we approach the 70th anniversary of the detonation of the first atomic bomb at Hiroshima, it is good to remind ourselves how much more powerful the Trident weapon system is compared to that first bomb. Remember, as you read the following, that a single Trident submarine carries up to 96 warheads.

One British Trident warhead is estimated to have a yield of 100 kilotons. This is 8 times the yield of the bomb dropped on Hiroshima and 4.5 times the yield of the bomb dropped on Nagasaki. Commander Powis, Captain of HMS Victorious Starboard crew said that the warheads were equivalent to more than 5 Hiroshima bombs.

The number of deaths which would result from the use of one Trident warhead would depend on where it was detonated and at what altitude. The explosion of one Trident warhead in a large built up area would result in fatalities several times more than recorded for Hiroshima and Nagasaki.

The use of one Trident warhead against a specific military target would be likely to result in significant civilian casualties, given that there would be at least small centres of population close to the explosion. Many military bases are not in isolated situations but are near large towns and cities.

The warhead mixture on a Trident submarine is difficulat to predict. A few missiles will carry only 1 nuclear warhead for the sub-strategic role. This warhead may have a lower yield. The remaining missiles will probably carry 8 warheads, but could carry 12. The MoD has said that each submarine will carry not more than 96 warheads, but that this figure could be revised in future. It is likely that Trident submarines will carry targeting data to enable missiles to be fired against the city of Moscow. Taking into account the use of decoy RVs and the effect of Moscow’s Anti Ballistic Missile defences, it would only need 3 or 4 Trident missiles to destroy the city of Moscow.

The independently targeted warheads can be used against separate targets, so long as the targets are all relatively close together – the size of the “footprint” could be around 150 km by 500 km. If 96 warheads were used against a range of military targets it is likely that hundreds of thousands of civilians of all ages would be killed. Deliberate use against civilian targets could result in the destruction of 96 large towns and cities.

The operational cycle for Trident submarines is likely to mean that in addition to the submarine on patrol, a second vessel would be in reserve. If all the missiles on both were used this would give a total of 192 warheads.

The total impact from the explosion of nuclear weapons is much greater than the initial damage and fatalities. There would be long term radiation hazards, social disruption and widespread ecological damage.