How to survive a nuclear explosion: Scientists reveal the safest places to take shelter

Since Russia’s invasion on Ukraine started almost a year ago, the threat of devastating nuclear war has for many felt closer than ever before.  

Now, a study reveals the best way to survive a powerful nuclear explosion if you’re inside a concrete building – as long as it hasn’t been toppled by the blast. 

According to the researchers, the best place to shelter is in the corner of a room, facing the direction of the blast, or to ‘duck and cover’, potentially behind a chair or table. 

However, people should steer clear of windows, corridors and doors as this is where extreme winds travel at the highest speeds, strong enough to lift people into the air and cause serious injury when they hit the ground.

The new study was conducted by researchers at the University of Nicosia in Cyprus, who used computer modelling to investigate the effects of a nearby nuclear blast for people inside a concrete building.

‘Before our study, the danger to people inside a concrete-reinforced building that withstands the blast wave was unclear,’ said author Dimitris Drikakis. 

‘Our study shows that high airspeeds remain a considerable hazard and can still result in severe injuries or even fatalities.’ 

Although the study didn’t mention Russia’s war on Ukraine, the researchers highlighted ‘increasing geopolitical tensions’ and the possibility of a ‘catastrophic’ nuclear scenario. 

A nuclear blast is usually measured by the amount of overpressure (the pressure in excess of the normal atmospheric value) in pounds per square inch (psi) – but this depends on distance from the nuclear bomb as it detonates. 

Anyone in the general vicinity of a nuclear bomb going off would be  instantly vaporised, while radiation can also pose a fatal risk. 

However, there is another potentially fatal danger – the blast wave generated by the explosion, defined as an area of pressure expanding outward at supersonic speeds. 

A blast wave can produce airspeeds strong enough to lift people into the air and cause serious injury or death, even in indoor spaces. 

‘Primary danger to human survivability in indoor spaces becomes the extreme high-speed winds that enter through the various openings in the building, e.g., window,’ the researchers say in their paper, published in Physics of Fluids.

‘Supersonic shock waves arising from the blast undergo expansion as they enter a room through an opening leading to channelling effects.’    

For the study, the team used computer modelling to simulate a reinforced concrete building featuring rooms, windows, doorways and corridors.

Researchers simulated a 750-kiloton nuclear explosion (with the the explosive power of 750 tons of TNT) from an atomic bomb, a type of nuclear bomb that uses nuclear fission.

Researchers said the explosion would give a blast wave with a radius of about 2.8 miles (4.6 km) at ground level, with a peak overpressure slightly over 7 psi.

Typically, overpressures of 5 psi cause ‘moderate’ blast damage, defined as the collapse of timber buildings, ‘universal’ injuries and widespread fatalities. 

According to the results, simply being in a sturdy building is not enough to avoid risk of injury or death, so people should choose their positions wisely. 

The most dangerous indoor locations to avoid are the windows, doors and corridors, although if there’s not enough time, hiding in the corner of a corridor might be safer than being in the middle of the corridor. 

Ultimately, the best option is to hide in the corner of a room, away from any openings such as a window or door, where air speed is higher. 

The authors stress that the time between the explosion and the arrival of the blast wave is only a few seconds, so quickly getting to a safe place is critical.

‘If people see the explosion from far away they have to take shelter ASAP,’ Drikakis told MailOnline. 

‘If they are at the window they should run away from it inside the building and take shelter in a room without openings or in the corners of the rooms/corridors.’ 

Unfortunately, survivors will have to contend with increased radiation levels, unsafe buildings, damaged power and gas lines, and fires, so they should ‘seek immediate emergency assistance too,’ Drikakis said. 

While the authors hope that their advice will never need to be followed, they believe the study can help prevent injuries and guide rescue efforts, should a nuclear blast occur. 

Nuclear weapons have been deployed twice in war, by the US against the Japanese cities of Hiroshima and Nagasaki in 1945 during World War II.  

Russian President Vladimir Putin has made a series of nuclear threats since the start of the war on Ukraine last year.

Russia’s invasion has triggered the biggest confrontation between Moscow and the West since the 1962 Cuban Missile Crisis when the two Cold War superpowers came closest to intentional nuclear war. 

Russia and the US are by far the biggest nuclear powers, together holding around 90 per cent of the world’s nuclear warheads – enough to destroy the planet many times over.

In September, Putin warned the West he was not bluffing when he said he’d be ready to use nuclear weapons to defend Russia. 

A few days later, he said the US had created a ‘precedent’ by dropping two atomic bombs on Japan in 1945.