The Atomic Bomb “Demon Core” Intended for Japan That Caused Tragedy in America

In the annals of nuclear history, few stories are as chilling as that of the “Demon Core.” This innocuous-looking sphere of plutonium, no larger than a grapefruit, never fulfilled its intended purpose as the heart of a third atomic bomb. Instead, it became the centerpiece of two tragic accidents at Los Alamos National Laboratory, claiming the lives of brilliant scientists and earning its ominous moniker.

The tale of the Demon Core is a reminder of the immense power and danger inherent in nuclear technology. It’s a story of scientific ambition, human error, and the fine line between groundbreaking research and catastrophe.

In this haunting chapter of atomic history, learn how a small metallic sphere came to symbolize the perils of the nuclear age and forever changed the landscape of scientific safety protocols.

The Birth of a Nuclear Nightmare

The Atomic Bomb "Demon Core" Intended for Japan That Caused Tragedy in America » Rufus Demon Core wc
Image Credit: Los Alamos National Laboratory, Attribution, via Wikimedia Commons

The Demon Core, initially known as “Rufus,” was born in the crucible of the Manhattan Project. Crafted as a plutonium core for a potential third atomic bomb, it never fulfilled its intended purpose due to Japan’s surrender in August 1945. However, its lethal potential remained intact, waiting to be unleashed in the most unexpected ways.(ref)

This 13.7-pound sphere of plutonium, measuring just 3.5 inches in diameter, held enough power to level a city. But instead of being dropped from a plane, it found its way into the hands of curious scientists eager to push the boundaries of nuclear physics.

The First Victim: Harry Daghlian

The Atomic Bomb "Demon Core" Intended for Japan That Caused Tragedy in America » Harry Daghlian wc
Image Credit: Unspecified, CC BY-SA 3.0, via Wikimedia Commons

On August 21, 1945, just days after the war’s end, 24-year-old physicist Harry Daghlian was working late at Los Alamos. His experiment involved surrounding the core with tungsten carbide bricks to study its approach to criticality.

In a fateful moment, Daghlian accidentally dropped a brick onto the core, causing a burst of radiation.

Realizing his mistake, Daghlian quickly dismantled the assembly, but the damage was done. He had received a lethal dose of radiation. Over the next 25 days, Daghlian suffered the horrific effects of acute radiation syndrome before succumbing to his injuries.

The Second Tragedy: Louis Slotin

The Atomic Bomb "Demon Core" Intended for Japan That Caused Tragedy in America » Louis Slotin wc
Image Credit: Los Alamos National Laboratory, Public domain, via Wikimedia Commons

Less than a year later, on May 21, 1946, the Demon Core claimed its second victim. Canadian physicist Louis Slotin, known for his daring approach to experiments, was demonstrating a criticality test to colleagues. Using a screwdriver to keep two beryllium hemispheres apart, Slotin was literally holding back a nuclear reaction with his bare hands.

In a heart-stopping moment, the screwdriver slipped. The hemispheres closed around the core, unleashing a burst of deadly radiation. Slotin’s quick action in separating the hemispheres likely saved the lives of his colleagues, but at the cost of his own. He died nine days later, ravaged by radiation sickness.(ref)

The Legacy of the Demon Core

The Atomic Bomb "Demon Core" Intended for Japan That Caused Tragedy in America » Demon core wc
Image Credit: Richard G. Hewlett, Public domain, via Wikimedia Commons

These tragic accidents sent shockwaves through the scientific community. They highlighted the immense risks associated with hands-on nuclear experimentation and led to significant changes in safety protocols at Los Alamos and beyond.

The Demon Core itself never saw use in a weapon. After the accidents, it was allowed to cool before being melted down and recycled into other cores. However, its deadly legacy lives on as a cautionary tale about the dangers of nuclear power and the importance of rigorous safety measures in scientific research.

Today, nuclear research continues, but with far more stringent safety measures in place. Remote handling systems, advanced monitoring equipment, and comprehensive training programs help ensure that the tragedies of the past are not repeated.

Martha A. Lavallie
Martha A. Lavallie
Author & Editor | + posts

Martha is a journalist with close to a decade of experience in uncovering and reporting on the most compelling stories of our time. Passionate about staying ahead of the curve, she specializes in shedding light on trending topics and captivating global narratives. Her insightful articles have garnered acclaim, making her a trusted voice in today's dynamic media landscape.