Theresa Tolmie-McGrane says she was abused from the age of six at a Catholic-run orphanage in Lanark in the 1960s and 1970s.
She describes more than a decade of physical, sexual and mental abuse at Smyllum Park Orphanage.
A BBC investigation has uncovered new evidence that more than 400 children who died at Smyllum are now thought to be buried in a mass grave in a nearby cemetery.
Produced by Judy Fladmark, filmed by Emily France and edited by Joshua Hollis.
File on 4: The Secrets of Smyllum Park is broadcast on BBC Radio 4 on Sunday 24 September 2017 at 17:00 BST. You can also catch up on the BBC iPlayer.