A number of problems, from today’s NRC Event Reports:
1. ASCO Valve informed the NRC of the results of its investigation into leaking valves at the Dresden nuclear plant in Illinois and Salem nuclear plant in New Jersey. In both cases, ASCO determined that U-rings from both valves had been manufactured from the wrong material. The U-rings became brittle over time, causing the valves to leak in both the energized and de-energized positions.
ASCO manufactured the U-rings between 1992 and 1995. Because of the turnover for that particular part, ASCO believes that most of the defective valves have been replaced. I find this less than comforting. ASCO’s report did not indicate how many other reactors it had provided the defective parts for, and apparently doesn’t care. If it’s any comfort, ASCO swears that they’ve been very careful since 1995: “Subsequent to 1995, ASCO has implemented a more rigorous lot and batch control to verify the material compound at incoming and dedication inspection.”
2. While performing relay maintenance yesterday evening, technicians at the Browns Ferry nuclear plant in Alabama inadvertently turned off Shutdown Cooling for the Unit 3 reactor, which was shut down at the time. Coolant temperature rose from 112.5 degrees fahrenheit to 122 degrees in the half-hour before the relay was restored to the proper position.
3. And, yesterday morning, a contract employee at the Ft. Calhoun nuclear facility in Nebraska was questioned and admitted being under the influence of an illegal substance. The employee’s plant access has been terminated, and he is currently in the custody of local law enforcement.
(Information from NRC’s Event Reports, available at www.nrc.gov.)