The Dangers and Implications of a Nuclear Fizzle: An Explainer

When discussing the detonation of a nuclear weapon, the possibility of a nuclear fizzle often arises. A nuclear fizzle occurs when there is insufficient fissile material to sustain a nuclear chain reaction. This article aims to elucidate what happens during a nuclear fizzle and the implications of such an event.

Understanding a Nuclear Fizzle

A nuclear fizzle, also known as a fizzle detonation, is the result of a nuclear weapon that fails to achieve sustainable nuclear fission due to a lack of fissile material. This situation can result in a partial or complete failure of the weapon to produce a significant explosion.

What Happens Without Sufficient Plutonium

When there is too little plutonium or other fissile material for the device to go critical (which means reaching a chain reaction sufficient to maintain and amplify the release of energy), the expected fission reactions do not occur. The amount of plutonium involved plays a crucial role in determining the outcome.

Partial Criticality (Fizzle): If the device is slightly supercritical or only remains supercritical for a short period, only a small amount of fission will occur. In this case, the plutonium may get dispersed throughout the explosive material used, which depends on the amount and symmetry of the high explosives, leading to the formation of smaller chunks or a fine dust/vapor of plutonium.

Full Supercriticality: As the amount of fissile material increases and the device goes more supercritical for a longer duration, the amount of fission will also increase. This would lead to a large burst of neutrons, which can be deadly from a distance, even at lower yields. With increasing yield, the vaporized plutonium would spread further and become more radioactive.

Detectability and Consequences

The occupational hazard of a fizzle is the ldquo;Dirty Bomb.rdquo; Here, the unreacted fissile material is ejected, and some will be spread over the ground, creating radiological hazards. This scenario involves alpha emitters and low-level neutron emissions, which are harder to detect.

Downwind Hazards

Civil Defense manuals from the 1950s and 1960s provide detailed descriptions of the fallout dangers. The radioactive material can be carried into the atmosphere, spreading over downwind hazard zones. This necessitates careful decontamination procedures and potentially long-term health monitoring for affected populations.

In Depth: Fission and Core Composition

For a plutonium isotope to undergo fission, two essential conditions must be met: sufficient compression and reflection of neutrons back into the material to sustain the fission reaction. The core of a nuclear weapon, containing the fissile material, is typically surrounded by neutron-reflecting metals like beryllium, and further enclosed by explosive materials designed to maximize compression and reflection.

Historical examples include the ldquo;Demon Core,rdquo; a 14-pound plutonium sphere used in experiments. Due to insufficient safety practices, it led to fatal radiation exposure for two scientists, highlighting the extreme danger of handling such materials.

Conclusion

The principles of a nuclear fizzle underscore the importance of critical mass and sustained fission in the successful detonation of a nuclear weapon. From a safety and risk management perspective, the potential for a fizzle underscores the need for rigorous safety protocols and the careful handling of fissile materials. Awareness and preparedness are critical for mitigating the risks associated with such events.