An elderly Catholic nun is among the three people convicted for damage they caused when they broke into a defense facility where enriched uranium for nuclear bombs is stored.

Sister Megan Gillespie Rice, 82, Michael Walli and Greg Boertje-Obed admitted to cutting the fence and gaining access to the Y-12 National Security Complex in Oak Ridge, Tennessee in July 2012.

The defendants called themselves "Transform Now Plowshares," a reference to the biblical phrase: "They shall beat their swords into plowshares, and their spears into pruning hooks."

The activists admitted to cutting several fences, walking through the complex for hours, spray painting slogans, stringing crime-scene tape and hammering off a small chunk of the facility.

Rice said during cross examination that she wished she hadn't waited so long to stage a protest inside the plant.

"My regret was I waited 70 years," she said. "It is manufacturing that which can only cause death."

According to the New York Times, Rice has been arrested 40 or 50 times for acts of civil disobedience and once served six months in prison.

The jury deliberated for almost three hours before returning a guilty verdict in Knoxville federal court. The Irish Times reports that Rice stood straight up and smiled when it was read.

The three peace activists were convicted of damaging a national defence premises. The penalty for such a crime carries a prison sentence of up to 20 years.

Prosecutors claim the break in at Y-12 disrupted operations endangered U.S. security and caused physical damage that cost over $8,500 to repair.

“These are people of conscious, nonviolence and justice. And they certainly put the US government to shame,” Paul Magno, a supporter of the activists and member of the group Plowshares, said afterward.

“We are a nation of laws. You can’t take the law into your own hands and force your views on other people,” Assistant US Attorney Jeffrey Theodore had said in a closing argument.

Janice Sevre-Duszynska, a member of the Association of Roman Catholic Women Priests who attended the trial to support Rice, said the activists were “challenging unjust, inhumane and immoral behavior filled with insatiable insecurity and greed.”

“My hope is that the people wake up to the freedoms being taken away in the name of so-called security as well as to the egregious waste of their hard-earned taxpayers’ money,” she said in a statement.

The nun who broke into a US nuclear-weapons facility