CREATE TABLE table_name_13 (close_of_reactor VARCHAR(255), rated_power VARCHAR(255), finish_construction VARCHAR(255))
When did the reactor that has a rated power of 945 MW and ended construction on May 10, 1978 close?
    
SQL: SELECT close_of_reactor FROM table_name_13 WHERE rated_power = "945 mw" AND finish_construction = "may 10, 1978"