Background
Flooding can have a big impact on a Nuclear Power Plant. Years ago, Fort Calhoun experienced flooding conditions that lasted several days. Luckily, the plant was designed well enough that no significant damage occurred.
After the extreme Flooding at Fukushima, regulators in the US ordered sites to walk down their plants, looking for ways water could get into the plant during a flood. To help sites with this, NEI developed NEI 12-07, Guidance for performing walkdowns. One member from our team assisted NEI in writing this guidance document.
One Plant’s Story
XCEED engineers led one of the flood inspection walkdown teams. During the walkdown, conduits were identified that were sealed, but no basis was available showing that the seals could withstand flood water.
XCEED engineers worked with the vendor, and found that the seals had never been qualified for flooding.
There were dozens of seals of this type that needed to be evaluated, so XCEED engineers developed a testing plan to test sample seals and determine their capability. A test rig was designed which put a static head on the sample flood seals. All work was performed at a testing facility offsite.
We found that the seals were capable of resisting flood depths of a few feet, which was adequate to protect the plant from flooding.
