Nuclear Waste Policy Act Amendment of 1986 - Amends the Nuclear Waste Policy Act of 1982 to provide that a State which either contains or shares a downstream portion of a major river located within 15 miles of a proposed Federal nuclear waste repository shall have the same rights and opportunities to participate in the site selection, review, and approval process as the State in which such repository is proposed to be located. Nullifies the decision of the President to approve the Secretary of Energy's May 1986 recommendation of three sites for characterization as candidate sites. Extends from January 1, 1985, to January 1, 1987, the deadline by which the Secretary must recommend three sites for characterization as candidate repository sites. States that if the Secretary determines before January 1, 1987, that operation of a second repository is not needed before the year 2010, then the Secretary shall: (1) nominate at least seven sites for site characterization as a first repository (including at least two sites located in crystalline rock); and (2) recommend three of the nominated sites for characterization as candidate sites by January 1, 1988. Requires the Secretary to complete an environmental impact statement for certain site characterization activities.