Could a woman survive only on her breast milk?

Bizarre question: You mean pumped and stored or day to day? Although breast milk is nutritious it would only work as a tempory bridge for survival. If a refrigerator or freezer were packed with a significant supply, it might sustain someone for a period, but the creation of the milk takes metabolic work and more fluid than is produced. Eventually the individual would die of starvation and or dehydration.