This phase I trial studies the side effects and best dose of triapine when given with radiation therapy and cisplatin in treating patients with stage IB2-IVA cervical or vulvar cancer. Triapine may stop the growth of cancer cells by blocking an enzyme needed for cell growth. Cisplatin is a drug used in chemotherapy that kills cancer cells by damaging their deoxyribonucleic acid (DNA) and stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells and shrink tumors. Adding triapine to standard treatment with cisplatin and radiation therapy may kill more cancer cells.