Which Reactortype has a gross capacity of 417 mw and an Electricity Grid of 27.12.1971?
CREATE TABLE "reactor_data" (
  "unit" text,
  "reactortype" text,
  "net_capacity" text,
  "gross_capacity" text,
  "construction_started" text,
  "electricity_grid" text,
  "commercial_operation" text,
  "shutdown" text
);
SELECT "reactortype" FROM "reactor_data" WHERE "gross_capacity"='417 mw' AND "electricity_grid"='27.12.1971';