The email — and the debate that has followed — have forced a painful reckoning here in Plymouth, where many residents have been supportive of the plant, which has long provided this historic town with high-paying jobs, a boon to the tax base and contributions to charities.

Finally, after weeks of escalating concerns, officials from the Nuclear Regulatory Commission agreed to meet with the residents and several elected officials here on Tuesday night.

The meeting drew 300 people in a snowstorm to a nondescript hotel ballroom, where many were armed with neon green placards saying “Shut Pilgrim Now.” The residents said they viewed the damaging email as exactly the sort of evidence they needed to finally make a substantive argument against the station.

But to the surprise of some at the meeting, the regulators acknowledged the problems. Donald Jackson, the inspector who wrote the email, discussed its main points. And the regulators said the problems raised in the message were being addressed and, most important, were not serious enough to close the plant.

“I have to have a sound technical and legal basis to do that,” Dan Dorman, the regional administrator for the Nuclear Regulatory Commission, said in an interview after the meeting.