San Onofre's Failed Steam Generators

In 2012, one of two recently-installed replacement steam generators in one of the San Onofre Nuclear Generating Station's two reactors sprung a leak and was required by federal regulations to quickly be shut down. Matters turned out to be much worse than was first suspected and the reactor shutdown turned out to be permanent.

A lot of research was done as to what caused the failure, which turned out to be a combination of Fluid Elastic Instability (a non-random vibration in the U-bend region of the steam generator, causing severe tube wear) and Flow Induced Vibration (a random vibration of individual tubes mainly in the straight portion of the U-tube bundles on the hot leg side). In other words, the tubes were not properly secured, although this may have been exacerbated by voids in the steam/water mixture in the hottest areas of the steam generators (only steam would allow greater vibration than a steam/water mixture). Additionally a thin film of water is supposed to be running all the way up the U-Bends, but there were probably dry spots.

These animations are based on actual documentation of the San Onofre reactor, now closed and approaching decommissioning as of this writing (2019).

Please be aware that these animations are very complex and CPU- and/or GPU- intensive. On some systems the frame rate may be noticeably degraded (30 fps is attempted on all systems). Program should *not* be left running for long periods if significant heating or battery usage occurs on your system. You can check the frame rate by pressing the authorship icon in the lower left corner of the screen.