My University of Nicosia in Cyprus is at it again, "Even people at a
   bank would have to get into the vault to be in the safest place..."
   [1]https://www.wired.com/story/you-might-survive-a-nuclear-blast-if-you
   -have-the-right-shelter/
   WIRED
   JAN 25, 2023 8:00 AM
   You Might Survive a Nuclear Blast—if You Have the Right Shelter
   The escalating risks of Russia’s war in Ukraine have led scientists to
   study the unthinkable and model the aftermath of nuclear detonation.
   Nuclear test
   PHOTOGRAPH: GETTY IMAGES
   IN A FLASH, a nuclear warhead unleashes the destructive power of
   hundreds of kilotons of TNT. The resulting inferno, and the blast wave
   that follows, instantly kill people directly in their path. But a new
   study finds that some people two to seven miles away could survive—if
   they’re lucky enough to find just the right kind of shelter.
   Dimitris Drikakis, a fluid dynamics researcher at the University of
   Nicosia in Cyprus, led the study both to illuminate the ongoing risks
   of nuclear escalation and to examine how one might have a chance at
   survival if the unthinkable should come to pass. “People have forgotten
   the devastating impacts nuclear war can have. But now we’re seeing the
   discussion starting again, and there’s a debate about the potential for
   nuclear war in Ukraine,” says Drikakis. “I think this kind of study
   raises awareness within the wider population that nuclear explosions
   are not a joke.”
   His grim research comes just as the Bulletin of the Atomic Scientists
   announced that it has ticked the Doomsday Clock forward, to 90 seconds
   until an apocalyptic midnight, citing the increasing nuclear tensions
   following Russia’s invasion of Ukraine. Scientists and artists
   developed the metaphorical clock to communicate risks posed by global,
   human-caused problems including climate change, but the dangers of
   nuclear war have been a major focus since its inception.
   Drikakis combed through scientific research on what the aftermath of
   nuclear weapon use would look like, and he spotted a gap: There’s
   little knowledge of the effects on humans indoors in the “moderate
   damage zone” a few miles from the epicenter, far enough away that
   buildings might not get blown to bits. He and his colleague Ioannis
   Kokkinakis focused on this area and published their work in the Physics
   of Fluids journal last week.
   Since no one’s going around testing nukes on buildings these days, this
   kind of research employs computer simulations. Drikakis and Kokkinakis
   simulated the blast effects of a 750-kiloton warhead—like the hundreds
   of larger bombs in Russia’s arsenal—delivered by an intercontinental
   ballistic missile, which would detonate about 3 kilometers above a
   metropolis. They studied how the supersonic shock waves would propagate
   through a three-room concrete structure situated in the moderate damage
   zone and assumed that the concrete was strong enough to withstand the 3
   to 5 pounds per square inch of pressure from the blast wave.
   This is a 3D illustration of the simulated air blast and generated
   blast wave 10 seconds after the detonation of a 750 kiloton nuclear
   warhead above a typical metropolitan city; the radius of the shock
   bubble at ground level is 4.6 kilometers. COURTESY OF I. KOKKINAKIS AND
   D. DRIKAKIS/UNIVERSITY OF NICOSIA
   Their research shows that, if a nuke were ever detonated in a modern
   city, some people in the surrounding areas would make it. They might
   have about five to 10 seconds after the initial flash to get to safety.
   If they happened to be in a thick concrete structure with few openings,
   like in a bank or a subway, they might survive if they used that
   limited time to run into the corner of a back room with few openings.
   Being in an enclosed space matters because, the researchers find, the
   blast winds following the initial fireball can be even more dangerous
   and deadly than the blast itself. These winds push outward behind the
   shock wave, and anyone facing the brunt of them could be slammed
   against a wall at high speed. The winds are especially dangerous if a
   person is near a door or window or in a corridor or an opening to a
   room. Winds quickly funnel through such areas, throwing people and
   furniture around—it’s like a storm let loose in a building.
   (If you are wondering whether you could copy the Indiana Jones move in
   The Kingdom of the Crystal Skull, surviving a nuclear blast by jumping
   inside a fridge, Drikakis says that might be possible. But it’s also
   possible the strong wind would hurl the fridge with Indy inside.)
   Ferenc Dalnoki-Veress, a scientist-in-residence and nuclear physicist
   at the Middlebury Institute of International Studies at Monterey,
   points out that if multiple buildings happen to lie between the
   structure you’re in and the incoming blast wave, that shadowing effect
   can lessen the airspeed and forces involved. Those in a basement might
   avoid the worst blast effects too. “A lot of people have a nihilistic
   point of view that there’s nothing we can do about it,” but that’s not
   the case, he says.
   Shown are the contours of the maximum airspeed attained during the
   first 10 seconds after the blast wave enters the window; overpressure
   equals 5 pounds per square inch. COURTESY OF I. KOKKINAKIS AND D.
   DRIKAKIS/UNIVERSITY OF NICOSIA
   But let’s be honest: Most people, even in the moderate damage zone,
   won’t survive. Hardly anyone lives or works in nearly windowless
   reinforced-concrete buildings, nor in the vicinity of a concrete
   bunker. (Even people at a bank would have to get into the vault to be
   in the safest place; people in a subway would get the most benefit in a
   station that’s very deep underground.) Most people live in timber-frame
   or other less-armored buildings.
   This shouldn’t be construed as a way to be safe in a nuclear explosion,
   says Dylan Spaulding, an earth scientist and nuclear expert at the
   Union of Concerned Scientists. Strong structures made of concrete with
   metal reinforcement and designed for seismic safety would survive the
   pressures the team modeled, he says, but those pressures would be
   enough to destroy most traditional, wood-framed houses and brick
   structures without reinforcement.
   And he points out that the blast wave is only part of the story. While
   it is the main source of danger in a non-nuclear explosion—like the one
   that rocked Beirut in 2020, which was caused by a large quantity of
   flammable ammonium nitrate stored at the city’s port—nuclear weapons
   also throw out ionizing radiation and heat, followed by radioactive
   fallout.
   Radiation exposure through the skin or inhalation can have many health
   effects, including skin burns, organ damage, and cancer. The range of
   radiation exposure could extend tens of miles from the epicenter, so
   people who survive the blast could later be felled by the radiation.
   Drikakis’ example focused on what’s called a “strategic” nuke deployed
   on an ICBM, but there are also “tactical” nukes, which are dropped by a
   plane onto a battlefield and which can blow up on the ground. Such
   explosions play out differently but can be as deadly and destructive,
   potentially exposing more people to lethal radiation doses, Spaulding
   says.
   Russia and the US also possess so-called low-yield nukes, which have 5
   to 10 kilotons of yield and are a little smaller than the 15-kiloton
   bomb dropped on Hiroshima. These would still inflict massive
   devastation and cross a dangerous red line, possibly escalating a
   conflict to the use of larger weapons.
   Humanity’s most destructive weapons have been used in war only once,
   when the US demolished Hiroshima and Nagasaki, Japan, with two atomic
   bombs at the end of the Second World War in 1945. Together they killed
   more than 100,000 Japanese civilians and injured many more. And
   Spaulding points out that along with experiments conducted at the
   Nevada Test Site, they offer some of the only real-world evidence about
   the kinds of structures that can survive an atomic blast, and how well.
   But last year Russian president Vladimir Putin insinuated that nukes
   are not off the table in his attack on Ukraine. While NATO leaders have
   not used such threatening rhetoric, the international organization
   conducted nuclear exercises in October, simulating dropping B61 nuclear
   bombs. US president Joe Biden’s Nuclear Posture Review the same month
   abandoned a “no first use” policy he previously supported. One could
   imagine nuclear risks in other conflicts too, like the possibility of
   North Korea using a nuke against South Korea, or Pakistan and India
   using them against each other.
   The world’s arsenals add up to about 12,700 warheads, according to an
   inventory by the Federation of American Scientists. That’s fewer than
   their peak of around 70,000 near the end of the Cold War, thanks to
   arms reduction treaties. But some of those pacts have since been
   dissolved, and the dangers never went away, as the Doomsday Clock’s
   metaphor illustrates.
   This is not a game, Drikakis says. The risks of a devastating nuclear
   strike are all too real, he says: “We have to maintain peace by
   understanding the risks of not maintaining the peace.”

References

   1. https://www.wired.com/story/you-might-survive-a-nuclear-blast-if-you-have-the-right-shelter/