I was happy to see today’s News and Observer editorial on the November mishap at Progress Energy’s Brunswick nuclear plant. This time the hand-tight bolts part made it into print, unlike the previous article by John Murawski which left that part out of the print edition for brevity’s sake, apparently.
I’ve got another blog post pending on this topic, based on the report that NRC released. I hope this incident is a reminder to Progress Energy that when one deals with nuclear energy, “close enough” isn’t good enough.
The Nov. 16 shutdown at Brunswick’s Unit 2 was caused by a coolant leak from a pressurized vessel that produces steam. Mildly radioactive water flowed out of the chamber rather than boiling inside. At one point, according to an N&O account, “the water was flowing out at a rate of over 10 gallons a minute, about 100 times more volume than would flow out under normal circumstances.”
As a result, according to the NRC, “instead of pressurizing the tensioning device to 13,000 psi, the team actually pressurized the device to 1,300 psi.” Later, Progress Energy personnel were “able to rotate 8 nuts by hand, 10 nuts by wrench with no agitation, 31 nuts by wrench and agitation, and 15 nuts by wrench with additional agitation,” the NRC said.
Got that? Those investigating the leak were able to turn some of the nuts on a reactor pressure vessel by hand. That’s not tight enough for a tire change.