Radiation shields (20) include an outer composite wall (22), an inner composite wall (24), and an enclosed fuel chamber (28) disposed between the inner and outer composite walls. A fuel may be contained within the enclosed fuel chamber (28). Spacecraft include one or more such radiation shields (20), and may further include a fuel cell (80) and a conduit (50) providing fluid communication between the fuel chamber (28) of the radiation shield (20) and the fuel cell (80). Methods of forming a radiation shield system include forming an enclosed fuel chamber between an outer composite wall and an inner composite wall of a radiation shield, and providing fuel within the enclosed fuel chamber.
