An elderly Catholic nun convicted of breaking into a Tennessee nuclear facility will likely stay out of prison after prosecutors decided today not to pursue sabotage charges rejected by an appellate court.

Megan Rice, 85, was sentenced to three years in prison for the 2012 break-in at the Y-12 National Security Complex in Oak Ridge, an incident that embarrassed U.S. officials and prompted security changes.

But last month, the 6th U.S. Circuit Court of Appeals reversed the sabotage convictions against Rice and two other peace activists, Michael Walli, 66, and Greg Boertje-Obed, 60. The court found that the three lacked the necessary intent for a violation of the federal Sabotage Act.

Prosecutors told defense attorneys they would not appeal the decision, said a spokeswoman for the U.S. Attorney's office in Knoxville.

The appellate court had upheld the trio's convictions for the lesser crime of injury to government property. But the three have already served more time than is usual on those charges, and were released from prison on May 16 pending resentencing, defense attorney Marc Shapiro.

Shapiro said Rice is "just ecstatic, delighted and very pleased to see that the confirmation that the 6th Circuit got it right and the government is not going to continue to press the issue."

A resentencing date has not yet been set.

The three were convicted of cutting fences to get into the facility the night of July 28, 2012, and they admitted to spray painting peace slogans and hanging banners. When a guard confronted them, they offered him food and began singing.

Prosecutors had contended the break-in at the primary U.S. site for processing and storing enriched uranium disrupted operations, endangered U.S. national security and caused physical damage. The three were convicted by a jury in May 2013.