What is a Pebble Bed Modular Reactor?
From the Eskom website: The PBMR, being purpose-designed for electricity generation, is inherently different from the Pressurised Water Reactor (PWR), the most common type in the world today [e.g. Koeberg]. It uses helium (a gas) to cool the reactor core and drive the turbines. The fuel is based on a ceramic coating of very small enriched uranium dioxide fuel particles (silicon carbide coated particles of less than 1 mm diameter) embedded in a graphite matrix. The fuel is proof against damage up to 1 600 degrees C and will not melt below 3,500 degrees C. The net result is a design which, if the unit is kept below a certain size (about 100 MW), cannot exceed the temperature where fuel damage and radioactive release could occur, even with no external cooling. The plant is therefore considered inherently or “walk away” safe. This limits the size of the plant but avoids the need for highly reliable, diverse and redundant safety systems that are used to ensure adequate safety on current rea
