Before revision: Water-moderated reactors Inside the core of a typical pressurized water reactor or boiling water reactor are nuclear fuel rods equivalent to the diameter of a large gel type ink-pen , each about 4 m long, which are grouped by the hundreds in bundles called "fuel assemblies".
After revision: Water-moderated reactors Inside the core of a typical pressurized water reactor or boiling water reactor are fuel rods with a diameter of a large gel-type ink pen , each about 4 m long, which are grouped by the hundreds in bundles called "fuel assemblies".