Aerial view of the Palo Verde Generating Station located in Tonopah, Arizona.

Palo Verde Generating Station

Palo Verde Generating Station (PVGS), located about 50 miles west of Phoenix near Wintersburg, is the largest nuclear energy facility in the United States. Palo Verde generates 4,000 megawatts in service of 4 million inhabitants of Arizona, California, New Mexico and Texas.

Nuclear power plants use the heat generated from nuclear fission (PDF) in a contained environment to convert water to steam, powering generators to produce electricity. The potential danger from an incident at a nuclear power plant is exposure to radiation. This exposure could come from the release of radioactive material from the plant into the environment, usually characterized by a plume of radioactive gases and particles.

Local and state governments, federal agencies, and the electric utilities have emergency response plans in the unlikely event of a nuclear power plant incident. The emergency response plans identify two “emergency planning zones” around the plant, the 10-Mile Emergency Planning Zone (PDF)  and the 50-Mile Emergency Planning Zone (PDF).  Emergency officials may ask those who live and work within the 10-mile radius to take protective actions such as sheltering, evacuation or proceed to the Reception and Care Center for the distribution of potassium iodide.

Learn the Emergency Classification Levels used during a nuclear power plant emergency:

  • Unusual Event—A minor problem has taken place. No release of radioactive material is expected. Federal, state and county officials will be notified of the problem. You will not be expected to do anything.
  • Alert—This is also a minor problem. Small amounts of radioactive material could be released inside the plant. Federal, state and county officials will be notified of the problem. You will probably not need to do anything.
  • Site Area Emergency—A more serious problem has taken place. Small amounts of radioactive material could be released near the plant. If you need to take protective action, sirens will be sounded. Government officials will tell you what you need to do over radio and television broadcasts.
  • General Emergency—This is the most serious kind of problem. Radioactive material could be released outside the plant site. Sirens will be sounded if you have to take any protective actions. You should turn on your radio or television immediately and listen for information on what you need to do. Research additional information on how to plan and prepare for a nuclear power plant emergency.

  • If an incident occurs at Palo Verde Generating Station, Maricopa County will activate the Emergency Siren Alerting System (PDF) in the 10-mile  Emergency Planning Zone surrounding Palo Verde Generating Station.  
    • When the sirens sound, residents are instructed to go indoors and tune into local television and radio stations KTAR 620 AM, KMVP 98.7 FM or KTAR 92.3 FM  to hear public safety instructions.
  • If you are told to evacuate, keep car windows and vents closed; use re-circulating air.  Go to the designated Reception and Care Center.
  • If you are told to take shelter, turn off the air conditioner, furnace and other air intakes.

  • When it is safe, evacuees will be notified they can return home.
  • Continue monitoring official sources of information for further instruction. Be aware that, depending on location, residents may be instructed to complete protective actions. 
  • Consult the Arizona Department of Agriculture (PDF) for information on any necessary actions to take with crops and livestock.