The boiling water reactor (BWR) is a type of light water nuclear reactor used for the generation of electrical power.
from York Digital Library (YODL) collection* therosewindow.com Painton Cowen's website, with many good images of rose windows* Tips & Tricks to Gothic Geometry How to design a rose window* Chartres Rose Window Geometry* Wagon Wheel Rose Windows of the Medieval Norman Cathedrals of Puglia - Photos