In autumn last year, one of the UK’s Royal Navy nuclear submarines skirted with disaster.
A depth gauge failed, allowing the Vanguard-class vessel to sink dangerously low beneath the waves. Thanks to eagle-eyed engineers the fault was spotted, and the submarine climbed towards the surface and away from catastrophe.
The Navy sub, one of four nuclear-armed vessels, was carrying 140 crew members as it traversed the Atlantic, so the human cost of such a tragedy is clear.
But what of the nuclear and environmental consequences?
Each vessel currently carries up to 12 missiles on board, and each missile carries up to four nuclear warheads – a maximum total of 48.
If the vessel suffered a catastrophic implosion, similar to that which killed all five passengers on board the Titan submersible in June, the Trident nuclear missiles on board would also suffer severe damage.
However, there would be no risk of them accidentally being launched.
‘If the hull implodes, then by extension a pretty valuable [weapon] will be lost or severely damaged,’ says Dr Sidharth Kaushal, a research fellow in sea power at the Royal United Services Institute (RUSI).
‘This means potentially radioactive waste within the oceans, because it would be very difficult to salvage [the wreck or missile] under those conditions at those depths.’
The Royal Navy has not commented on the depth the submarine reached, although Military Today has reported the maximum operation depth of a Vanguard-class submarine is around 500 metres.
However, there is likely a buffer zone beyond that figure before a submarine enters the ‘crush depth’.
‘The crush depth of a submarine is probably somewhat lower than the maximum operating depth, so I don’t know how close it was to implosion,’ he says.
In the event of such an implosion, the wreck would sink, taking it even further out of reach – the deepest part of the Atlantic Ocean is more than 8,000m below sea level.
What is Trident?
Trident is the UK’s nuclear weapons system, which is made up of four nuclear submarines. At least one sub is on patrol in the seas at all times.
Each vessel currently carries up to 12 missiles on board, and each missile carries up to four nuclear warheads (bombs) on the top – a maximum total of 48.
Each bomb is around eight times as destructive as the Hiroshima bomb which killed more than 140,000 people in 1945.
The government is currently in the process of upgrading the submarines as the current vessels will begin to come out of service from 2032.
This means a potential nuclear waste leak in some of the most remote parts of the ocean, with varying outcomes. While the warheads themselves may remain contained in the wreck of the submarine, over time, decomposition of the submarine would like result in leaching of the material.
‘There would be no immediate massive radioactive risks,’ says Dr Kaushal.
‘For example, the Russians have been dumping the radioactive waste from their nuclear submarines in the Arctic for a very long time, for decades in fact, so the risk tends to accumulate when you have years of radioactive material being dumped in a given part of the ocean.’
An estimated 18,000 radioactive objects lie at the bottom of the Arctic Ocean, including 19 vessels and 14 reactors. In the past decade Russia has begun the process of cleaning up after itself – primarily to boost trade through growing shipping routes as winter sea ice continues to recede under global warming.
Progress has stalled somewhat since the country’s invasion of Ukraine.
Meanwhile, on the other side of the world, Japan is continuing to release contaminated water from the Fukushima nuclear power plant, further adding to the ocean’s nuclear load.
Dr Kaushal adds: ‘A single Trident [submarine] suffering potentially catastrophic damage, and radioactive material being irretrievable, would be a significant problem from a national security standpoint, but the environmental consequences, although severe, would not be immediately catastrophic.’
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