Ms Carr, 40, says she suffered regular sex attacks by a masked gunman while her partner, Jon James, 38, was chained to a radiator nearby.
In an interview with the Mail on Sunday, the couple, who travelled to the breakaway republic to help set up a children's centre, said they were subjected to mock executions and beaten.
Ms Carr, who has a 12-year-old son, Ashok, said she was repeatedly raped over several months.
"The first time, I tried to resist. I said, `No, no,' but he started hitting me around the face and neck. I thought then I had to go through with it, but it would not be me he was raping. He couldn't touch my spirit.
"I believe that when the guard got to know us as people, he realised it was wrong to rape me. It stopped and he apologised to me."
Mr James said: "I could do nothing but be there for Camilla. Of course I wanted to protect her and stop her going through this - but I couldn't. It was hell."
Ms Carr described how their guards carried out mock interrogations, and on one occasion ordered them to stand against a wall at riflepoint.
She said: "I was thinking, `Is this it?' We were prepared for death and I was shaking like a leaf and panting."
The incident ended when one of the guards' rifles jammed as he tried to pull back the bolt.
The couple, both divorcees, who met in 1995, set off for the war-ravaged country in a pounds 500 Lada to help set up a centre for children in the capital, Grozny.
They were captured on 2 July 1997, when gunmen burst into their room.
Ms Carr, from Bath, and Mr James, from the Forest of Dean, tried to befriend their four captors, who they believed were former soldiers trying to make money out of hostage-taking. The men never revealed their faces and wore masks whenever they were near.
They said they had forgiven the men who put them through the 443-day ordeal, during which they were held in 14 locations.
The experience had brought them closer together, they said. "We were so lucky," Ms Carr said. "We were together, so we could comfort each other physically and spiritually."
The couple were freed after the intervention of a Russian businessman.Reuse content