GENPATSU.IO

原発 — Nuclear Risk Simulator

Descend into the reactor

CONTAINMENT LEVEL 01 // SOCIETAL IMPACT

Beyond the Exclusion Zone

Evacuation & Displacement

Over 154,000 residents were evacuated from the Fukushima exclusion zone. Decades later, many towns remain uninhabitable. The human cost of nuclear incidents extends far beyond radiation exposure -- communities fracture, cultural heritage dissolves, and generations lose their sense of place.

Displacement radius 30 km

Policy & Governance

Nuclear energy policy sits at the intersection of climate science, geopolitics, and public trust. After Fukushima, Japan shuttered all 54 reactors. Germany accelerated its nuclear phase-out. Each policy decision carries consequences measured in decades of energy infrastructure and environmental impact.

Reactors shutdown post-2011 54

Community & Health

The psychological toll of nuclear accidents persists long after radiation levels normalize. Stigmatization of evacuees, elevated anxiety disorders, and disrupted social networks create invisible wounds. Nature, however, tells a different story -- wildlife thriving in exclusion zones reveals life's persistent adaptation.

Long-term health monitoring 40+ years

CONTAINMENT LEVEL 02 // ENGINEERING SYSTEMS

Barriers Between Us and the Atom

Cooling Systems

A nuclear reactor's cooling system is its lifeline. Primary coolant loops carry heat from fission to steam generators at temperatures exceeding 300C. When cooling fails -- as at Fukushima after the tsunami disabled backup generators -- the fuel begins to melt within hours. Redundancy is the philosophy: multiple independent cooling circuits, each capable of preventing catastrophe alone.

Core temperature (normal) 320C

Containment Design

Modern reactor containment is defense-in-depth: fuel pellet ceramic, zirconium alloy cladding, steel pressure vessel, reinforced concrete containment building. Each layer is designed to be independently sufficient. The containment dome -- typically 1.2 meters of pre-stressed concrete with steel liner -- must withstand internal pressures from a loss-of-coolant accident.

Containment wall thickness 1.2 m

Control & Safety

Control rods -- neutron-absorbing materials like boron carbide or hafnium -- regulate the chain reaction. In emergency SCRAM, rods insert fully within 2-4 seconds, halting fission. But decay heat persists for days after shutdown, requiring continued cooling. The Fukushima disaster demonstrated that stopping the chain reaction is only half the battle.

SCRAM insertion time 2-4 sec

CONTAINMENT LEVEL 03 // ATOMIC PHYSICS

The Heart of the Reaction

Nuclear Fission

When a neutron strikes a uranium-235 nucleus, it splits into lighter elements, releasing 200 MeV of energy and 2-3 additional neutrons. This chain reaction, when controlled, generates immense thermal energy. When uncontrolled, it is the mechanism behind nuclear weapons and meltdown scenarios. The difference between power and catastrophe is measured in milliseconds of neutron moderation.

Energy per fission event 200 MeV

Radiation Types

Alpha particles -- helium nuclei -- are stopped by paper but devastate biological tissue if ingested. Beta particles penetrate further, requiring aluminum shielding. Gamma rays demand lead or concrete. Neutron radiation, unique to nuclear reactors, requires hydrogen-rich materials. Understanding these types is fundamental to grasping why nuclear accidents produce such varied and persistent hazards.

Gamma ray penetration Lead / Concrete

Radioactive Decay

Radioactive isotopes decay at rates measured in half-lives -- from fractions of seconds to billions of years. Cesium-137, released at Chernobyl and Fukushima, has a 30-year half-life. Plutonium-239: 24,100 years. These timescales mean nuclear waste outlasts civilizations. Storage solutions must remain stable for periods longer than recorded human history.

Cs-137 half-life 30.17 years

Nature Reclaims

In the exclusion zones of Chernobyl and Fukushima, forests have overtaken streets. Wolves, wild boar, and Przewalski's horses roam through abandoned reactor complexes. Moss creeps across concrete containment walls. Mushrooms -- some highly radioactive -- fruit in the reactor shadows. Nature does not judge the atom; it simply persists, adapts, and reclaims what was briefly borrowed.

原発の跡地に、自然は静かに還る。

At the site of the nuclear plant, nature quietly returns.