Apparently this last Sunday night was a bad night for Entergy, the corporation that owns Vermont Yankee Nuclear Reactor and is suing the State of Vermont. On Sunday night as I report earlierVermont Yankee had to step Vermont Yankee’s energy production down to 36% because of a recirculation pump malfunction. Now I just saw this article from the American Independent stating that Entergy’s Michigan Palisades Reactor “abruptly powered down on Sunday night when an electrical malfunction took out the power supply to several safety-related valves and switches.” here is an excerpt from the article –
Entergy faces another special investigation over malfunction at Michigan’s Palisades
By Eartha Jane Melzer | 09.29.11
The Nuclear Regulatory Commission has sent a special investigation team to Entergy’s Palisades nuclear power plant to examine the circumstances around the plant’s latest unplanned shutdown.
Palisades 798 MW pressurized water reactor, located about 70 miles southwest of Grand Rapids on Lake Michigan, abruptly powered down on Sunday night when an electrical malfunction took out the power supply to several safety-related valves and switches.
“The issue involved plant workers who were performing maintenance activities on an electrical panel when a small metal piece located inside the breaker panel came into contact with another metal piece and caused an arc,” the NRC said Wednesday. “This resulted in a series of electrical issues that caused the plant to shut down and sent signals to multiple plant systems causing certain safety pumps to start and some safety valves to reposition.”
Officials say the plant has been controlling temperature by venting steam, that contains low levels of tritium, into in the environment.
Tritium is a radioactive isotope of hydrogen that has a 12-year half life.
“The plant is in a safe shutdown condition but we have a number of questions about the complexity of the series of events that led to the reactor trip and want to better understand the actions taken by the plant staff before the reactor shutdown and in response to the event,” said NRC Region III Administrator Mark Satorius.
The agency said it will release a report from the special investigation within 45 days.
The shutdown at Palisades is the second this month and occurred just five days after the plant restarted from a shutdown triggered by a leak in the plant’s cooling system. The NRC has not yet released the report from the special investigation into that event. The agency also inspected the plant in August after a water pump failed.
With three problematic incidents this quarter, Palisades may be flagged for ongoing additional oversight by the NRC.
“This would be appropriate,” said David Lochbaum, a nuclear power expert with the Union of Concerned Scientists, “but NRC should go a step further and look to see if there is a corporate hand in the problems.
“Anytime there is a series of problems, it’s worth checking,” he said, “Are the plants being given enough money for operations? Are appropriate standards in place?”
link – http://www.americanindependent.com/196469/entergy-faces-another-special-investigation-over-malfunction-at-michigans-palisades
link to NRC Investigation announcement – http://www.nrc.gov/reading-rm/doc-collections/news/2011/11-034.iii.pdf