Summary: If Cuba obtains the help needed to complete construction of its two Soviet-designed nuclear power reactors, the United States will need assurances that they are built and will be operated in a way that does not pose a risk to the United States in the event of an accidental release of radioactive material. Although work has halted on the two reactors, the first unit is believed to be virtually finished while the second is between 20 and 30 percent complete. The main reactor components have not yet been installed, and the nuclear fuel has not been delivered. Concerns about the reactors center on the questionable quality of the construction, limited regulatory oversight, inadequate training for operators, lax safety standards, and the absence of a Cuban industrial infrastructure to support the reactors' operation and maintenance. Concerns also exist that the upper portion of the containment dome was designed to withstand pressures of only seven pounds per square inch. Because Russia demands hard currency as payment for--and Cuba now lacks the money to buy--equipment needed for the reactors, when the reactors will start up is unclear. Continued monitoring of Cuba's progress toward completing the reactors is warranted.