This is a simplified 3D model of the Windscale Pile-1 reactor. Active from 1950 to 1957, the plant was used to produce weapons-grade plutonium for the UK’s first atomic bombs.

On October 10, 1957, a fire broke out in the reactor core—an event that became the worst nuclear accident in UK history. What prevented a disaster on the scale of Chernobyl was the presence of air filters atop the chimneys. Initially mocked by colleagues and dubbed “Cockcroft’s Folly,” these filters were installed at the insistence of Nobel Prize-winning physicist John Cockcroft—a decision that likely saved northern England from widespread radioactive contamination.

Model Overview

This 3D model is a functional, visual aid designed to help understand the structure and operation of Windscale Pile-1, including how the accident occurred. It consists of 6 main parts:

Base Structure
Includes the core housing, the water channel (used to drop fuel cartridges), and the cooldown pool.

Roof Section
Features the inspection hole (used to detect the fire after several hours) and a labeled nameplate.

Graphite Core
Designed in the original octagonal shape with channels for inserting fuel cartridges.

Chimney

Filter Gallery (“Cockcroft’s Folly”)
Sits atop the chimney.

Fuel Cartridge
Sized to fit a mini glow stick (4.5 mm x 40 mm) to simulate glowing uranium.
I used this: Amazon Link

Limitations

This model is not to scale and is not scientifically accurate in detailed engineering terms. It is a simplified version intended for educational and demonstrative purposes—think of it as the “Fisher-Price” edition of a real reactor.

I’m neither a nuclear engineer nor a professional 3D designer, but I’ve done my best to capture the key components and functions to illustrate how the plant worked and why the 1957 fire was so significant. I may release updated versions in the future as I continue to research and learn more.

Feedback, suggestions, and remixes are very welcome!

Print Settings & Recommendations

Material: Standard PLA in various colors

Layer Height: 0.2 mm

Infill: 10%

Supports: Not needed

Brim: Recommended for printing the cartridges

Note: Print 2 or more cartridges so you can push one through the core, simulating real operation.

Sources:

• Wikipedia
• MT Cross: The Windscale Pile 1 Accident in ‘57, subsequent clean-up & decommissioning – 2014
• Lorna Arnold: Windscale 1957: Anatomy of a Nuclear Accident – 1992