3 ms·
Because the article isn't clear: no, this isn't about pebble bed reactors. This is about a type of fuel where a little bit of uranium has been encased in a numb
by pjscott 6y ago
Because the article isn't clear: no, this isn't about pebble bed reactors. This is about a type of fuel where a little bit of uranium has been encased in a number of protective layers, such that the fuel will remain safely contained in its tiny packaging even at very high temperatures. You take a bunch of these poppy-seed-sized things and embed them in graphite rods or pellets, which both keeps them in place and acts as a moderator for the reaction. These can then be used in a variety of reactors, including (but not limited to) pebble bed reactors.
- oxymoron 6y agoThe confusing part about the article was that it initially stated that they were very small, and then went on to speak about billiard ball size. Does that mean that the protective coating is very thick, or that there’s a range of sizes for the actual uranium mass? I remember reading in one of Feyman’s biographies about how he visited an early fuel plant, and was horrified to see them storing what amounted to a near a critical mass in barrels, in long rows. we’ve come some way since.
- pjscott 6y agoThe TRISO fuel particles are very small -- about a millimeter or so in diameter. The "billiard ball sized" fuel pebbles designed for the Xe-100 reactor are graphite balls with a bunch of TRISO fuel particles embedded in them.