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Three Mile Island warning sirens will be tested this week, despite closure of nuclear plant in September


Three Mile Island will sound its 96 sirens located throughout the region to test the system at 12:15 p.m. Thursday, June 4.

This is one of two tests of the TMI emergency sirens that are held each year by Exelon Generation, owners of the TMI Unit 1 reactor in Londonderry Township.

The sirens are located throughout Cumberland, Dauphin, Lancaster, Lebanon and York counties in the area that makes up the 10-mile emergency planning radius around TMI. 

Exelon permanently shut down Unit 1 on Sept. 20, 2019. The company has requested the Nuclear Regulatory Commission approve changes that would exempt Exelon from all off-site emergency planning requirements currently imposed upon the company, including maintaining the siren system.

NRC staff in a May 5 filing has recommended the NRC approve the exemption request sought by Exelon. Staff in the document said approving the request would provide “an adequate basis for an acceptable state of emergency planning” and “reasonable assurance that adequate protective measures can and will be taken in the unlikely event of a radiological emergency at the TMI site.”

The Exelon request is still pending until a final decision is made by the commission.

Exelon has requested the commission approved the changes by Aug. 30. Exelon proposes to implement the changes in January 2021, when the company says that due to the Unit 1 shutdown, conditions on TMI will have changed to where a release of radiation into the atmosphere in excess of Environmental Protection Agency safety thresholds will no longer be considered “credible.”

The watchdog group TMI-Alert opposes the Exelon request, saying emergency planning requirements should be kept as is until all nuclear fuel is gone from the island, and until both Units 1 and Unit 2 are fully decommissioned.

Unit 2 has been permanently shut down since the accident in March 1979.

TMI-Alert’s request for a hearing on the Exelon request was denied in January by the Atomic Safety and Licensing Board, a panel that rules on hearing requests on behalf of the NRC.