A new study has discovered the best places to be during a nuclear attack.

Time and options are usually short when the sirens go off. 

Conventional thinking is that taking shelter underground or in a reinforced building might be your best bet for survival. But is this true? We need actually to carry out extensive testing to guess. 

Little comfort for people should the unthinkable happen. But, researchers from the University of Nicosia may have provided the first technical study testing whether this conventional thinking has any validity. 

In a new study published in Physics of Fluids, the team simulated an atomic bomb explosion from a conventional intercontinental ballistic missile and the subsequent blast wave to investigate how it might affect those taking cover within an underground bunker. 

Being underground or in a strong structure on the surface, might not save your afterall

On the surface, the blast wave can topple structures and injure anyone outside in the moderate damage zone. However, they found that stronger structures, like concrete ones, can withstand the impact and survive.

The scientists studied how a nuclear bomb wave travels through a standing structure using sophisticated computer modeling. They were able to compute the speed of the air following the blast wave and identify the best and worst places to be, thanks to their simulated structure, which included rooms, windows, doorways, and hallways.

"Before our study, the danger to people inside a concrete-reinforced building that withstands the blastwave 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."

Their findings suggest that merely being in a robust structure is insufficient to eliminate risk. The small areas have the potential to boost airspeed, and the blast wave's involvement causes air to reflect off walls and curve around corners. 

In the worst circumstances, this can generate a force that is 18 times greater than the weight of an adult human.

"The most dangerous critical indoor locations to avoid are the windows, the corridors, and the doors," said author Ioannis Kokkinakis. "People should stay away from these locations and immediately take shelter. Even in the front room facing the explosion, one can be safe from the high airspeeds if positioned at the corners of the wall facing the blast."

Contours of the maximum airspeed attained during the first 10 seconds after the blast wave enters the window; overpressure of 5 psi. Credit: I. Kokkinakis and D. Drikakis, University of Nicosia, Cyprus

The authors emphasize the importance of moving swiftly to a safe location because there is just a brief window between the explosion and the arrival of the blast wave.

"Additionally, there will be increased radiation levels, unsafe buildings, damaged power and gas lines, and fires," said Drikakis. "People should be concerned about all the above and seek immediate emergency assistance."

The authors contend that knowing the impacts of a nuclear explosion can prevent injuries and direct rescue operations, while they hope their advice will never be required.

You can read the study for yourself in the journal Physics of Fluids.

Abstract

This study investigates the nuclear blast effects on humans inside a building within a moderate damage zone. These effects depend on many parameters that must be better understood. In addition, the nuclear blast effects will spread further away than the devastating destruction zone, where most people are killed instantly. However, these injuries will vary depending on a person's position in the building and the air velocities attained when the blast wave enters indoors. The blast wave effects are examined for an indicative, easily reproducible indoor arrangement. The airspeed behind the blast wave accelerates to even higher velocities in the interior. The supersonic shock waves arising from the blast undergo expansion as they enter a room through an opening leading to channeling effects. The results show that most of the air is directed toward the corridor rather than through the opposite room's door, leading to high airspeed developed in rooms further down the aisle. The airspeed attained in the interior is calculated for two blast wave overpressures, 3 and 5 pounds per square inch, for which most concrete buildings do not collapse. The data reveal that the force applied to a standing person from the speed of the gusts formed at several locations in the interior is equivalent to several g-forces of body mass acceleration capable of lifting and throwing any person off the ground. It is then the impact onto solid surfaces that can lead to severe injury or death. Finally, the results reveal preferential areas in the rooms where a human can avoid the risk of exposure to the highest wind forces.