Neither Willard Richards nor Wilford Woodruff suggested that JS claimed that hades was the Greek word translated as prison, as indicated here by Franklin D. Richards. The Greek word in 1 Peter 3:19 translated in English as prison is phylakē. (Aland et al., Greek New Testament, 799.)
Aland, Kurt, Matthew Black, Carlo M. Martini, Bruce M. Metzger, and Allen Wikgren, eds. The Greek New Testament. 3rd ed. Stuttgart, Germany: United Bible Societies, 1985.