--- On Thu, 5/2/13, dave <dengv...@charter.net> wrote: > SL1 was caused by a deliberate act of an employee who wanted > to > embarrass his boss. He pulled a control rod ... or several > and got pined to the roof by the steam. They buried his coffin > encased in several tons of lead.
What caused it was one shift was doing maintenance on the control rod motors then the next shift's job was to reinstall them. The reactor had one large control rod and some smaller ones. The rods were inadequate to control it so additional strips of boron were attached to them, making a very close fit in their channels. The heat and cooling water caused the "poison strips" to swell and flake, frequently jamming the rods. The official investigation results were that the main rod was stuck, one man stood atop the containment vessel to get a good grip on it to pull it up far enough to connect it to the motor drive. It snapped loose, came up all the way and the poor sod didn't even have enough time to think about beginning to think "oh crap". Other reactors around the world were checked to see if there were any with a design that could fail in the same way by pulling out one rod. Only one was found, in Iceland. The fix was simple, put a safety stop on the thing so that one rod couldn't be pulled up too far. ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite It's a free troubleshooting tool designed for production Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
