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TMI Alert wants action over nuclear reactor’s steam generators

By Dan Miller

danmiller@pressandjournal.com

717-944-4628
Posted 3/20/19

The watchdog group TMI Alert has filed a petition with the Nuclear Regulatory Commission, requesting NRC take an “enforcement action” concerning steam generators that were installed in …

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TMI Alert wants action over nuclear reactor’s steam generators

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The watchdog group TMI Alert has filed a petition with the Nuclear Regulatory Commission, requesting NRC take an “enforcement action” concerning steam generators that were installed in the Unit 1 reactor of Three Mile Island in 2010.

According to TMI Alert, data indicates that these steam generators can self-destruct from excessive vibrations and fluttering under reactor transient conditions.

“We want the fluttering behavior to be studied and analyzed,” Scott Portzline, security consultant to TMI Alert, told the Press & Journal on March 18.

According to the data cited by TMI Alert, the fluttering can be so severe that the steam tubes within the steam generators bang into each other and rupture.

Twenty-two months after the new steam generators were installed, during a refueling outage, it was learned that some of the tubes had exhibited excessive wear from this fluttering behavior under normal temperatures, TMI Alert said.

Internal damage would destroy the radiation barrier function of the steam tubes, releasing radiation directly into the environment in what is called a “containment bypass accident,” according to TMI Alert.

These rapid releases would allow no time for an evacuation and would represent what TMI Alert calls a “fearful and dangerous occurrence.”

TMI Alert filed its petition with the NRC on March 11.

In a response that Portzline provided to the Press & Journal, Perry Buckberg, an NRC senior project manager, said in an email that the NRC had received the submission from TMI Alert, and that a review by NRC staff “has begun.”

David Marcheskie, a spokesman for Exelon Corp. which owns Unit 1 of TMI, provided the Press & Journal with a letter from the NRC dated March 5, referring to the fall 2017 inspections of the steam generator tube that were conducted by Exelon.

“Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by its technical specifications,” the letter says.

“In addition, the NRC staff concludes that there are no technical issues that warrant followup action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation, and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units,” the letter states.

Marcheskie added on behalf of Exelon, “Three Mile Island Unit 1 operates at the industry’s highest level of excellence in safety and performance. TMI steam generators are thoroughly inspected by industry experts every 24 months, with findings submitted to the Nuclear Regulatory Commission for review. TMI has a comprehensive monitoring and maintenance plan that meets all NRC requirements.”