Russian Suspension Agreement Extension Act of 2020 This bill extends limits on the importation of Russian low-enriched uranium, a fuel for nuclear reactors, and contains other related provisions. (These limits stem from a 1992 agreement with Russia to end a Department of Commerce antidumping investigation into Russian uranium imports.) The bill extends these limits, which are currently set to expire in 2020, to 2040. The bill also specifies the maximum amounts of qualifying uranium that may be imported each year for 2021-2040. The Department of Commerce shall (1) administer these import limitations, and (2) periodically review U.S. demand for uranium for nuclear reactors and adjust the limits accordingly. Currently, qualifying uranium imported for the Department of Energy inventory do not count against these limits. The bill eliminates this exception but maintains two other exceptions for uranium imported for use in the initial core of a new reactor or for reprocessing and reexportation.