question: The Rocky Flats National Wildlife Refuge was previously a buffer zone for a production facility of what?
answer: nuclear weapons
context: Title: Rocky Flats Plant
  Passage: The Rocky Flats Plant was a former nuclear weapons production facility in the western United States, near Denver, Colorado.  Operated from 1952 to 1992, it was under the control of the U.S. Atomic Energy Commission (AEC), succeeded by the Department of Energy (DOE) in 1977.
  Title: Flattery Rocks National Wildlife Refuge
  Passage: Flattery Rocks National Wildlife Refuge is the northernmost of the three refuges (along with Quillayute Needles and Copalis) which make up the Washington Maritime National Wildlife Refuge Complex, a group of 870 islands, rocks, and reefs extending for more than 100 miles along Washington's coast from Cape Flattery to Copalis Beach.  These islands are protected from human disturbance, yet are close to abundant ocean food sources.  They are closed to the public, with wildlife observation only from boats and the mainland, and a 200-yard buffer zone surrounding each island.
  Title: Yukon Flats National Wildlife Refuge
  Passage: The Yukon Flats National Wildlife Refuge is a protected wetland area in the U.S. state of Alaska.  It encompasses most of the Yukon Flats, a vast wetland area centered on the confluence of the Yukon River, Porcupine River, and Chandalar River.  The area is a major waterfowl breeding ground, and after a proposal to flood the Yukon Flats via a dam on the Yukon River was turned down, the Yukon Flats were deemed worthy of protection.  The Alaska National Interest Lands Conservation Act established the refuge in 1980.  It is the third-largest National Wildlife Refuge in the United States, although it is less than one-half the size of either of the two largest, the Arctic National Wildlife Refuge, or the Yukon Delta National Wildlife Refuge.  The refuge is administered from offices in Fairbanks.
  Title: Audubon National Wildlife Refuge
  Passage: Audubon National Wildlife Refuge is a 14739 acre National Wildlife Refuge in the U.S. state of North Dakota.  The refuge is managed by the U.S. Fish and Wildlife Service and is the centerpiece of the Audubon National Wildlife Refuge Complex, which includes numerous other refuges in the region.  Originally designated as the Snake Creek National Wildlife Refuge in 1955, the refuge was renamed in 1967 in honor of the artist and naturalist John James Audubon.  Most of the refuge area is a lake known as Audubon Lake which is managed by the U.S. Army Corps of Engineers.
  Title: Rocky Flats National Wildlife Refuge
  Passage: The Rocky Flats National Wildlife Refuge is a unit of the National Wildlife Refuge System in the United States located approximately 16 mi northwest of Denver, Colorado.  The site was previously the Rocky Flats Plant's security buffer zone and is not currently open to the general public for access.
citations: Rocky Flats Plant Rocky Flats National Wildlife Refuge