The Tohoku earthquake and tsunami that rocked northern Japan on March 11th, 2011 has left a devastating impact on the island nation. The earthquake also caused severe damage to a nuclear power plant in the Fukushima prefecture, which has been the subject of world news headlines for the past several weeks.
The Fukushima incidents have been classified as a Level 7 emergency as a result of the hydrogen gas explosions, cracks in the pressure vessels of multiple reactors, and leakages of radioactive water. In the wake of this terrible disaster, many people are wondering if a situation like the one in Japan could ever happen here in Phoenix.
Just 45 miles west of Phoenix, the Palo Verde Nuclear Generating Station (PVNGS) is the nation's largest nuclear plant. It provides electricity to Phoenix as well as other parts of Arizona and southern California. Palo Verde is owned by six different utility companies and is operated by Arizona Public Service (APS).
As the nation's largest power plant, Palo Verde is capable of cranking out 3,875 megawatts under full load. Palo Verde generates approximately 30 million megawatts of power a year. Unlike coal or natural gas power plants, Palo Verde has a zero carbon-emission level. The only byproduct of daily operation is water vapor.
Construction of the plant began in 1976 under the direction of Bechtel Corp., one of the world's largest contracting and construction firms. Reactors one and two came online in 1986, and reactor three came online in 1988.
One unique thing about Palo Verde is that it is one of the few nuclear plants in the world that is not close to a large body of water. Other plants are often located near a major water source such as a river, lake, or ocean. Palo Verde relies entirely on reclaimed municipal water from the City of Phoenix for its cooling needs. Because of its location, the plant is not at risk for tsunamis or any sort of flooding.
The threat of damage from earthquakes is also extremely unlikely. Palo Verde is located in a very geologically stable area. The town of Wintersburg, Arizona was surveyed extensively before the plant was built. The M7.2 earthquake in April of 2010 that occurred near Baja California, Mexico (which was felt by many Phoenix residents) did not affect operations at the plant.
Besides its location, Palo Verde is also safer by design. The plant consists of three pressurized water reactors, or PWRs, known as Palo Verde 1, Palo Verde 2, and Palo Verde 3. Pressurized water reactors are an entirely different design from the Fukushima Daiichi plant in Japan, which uses an older style design known as a boiling water reactor.
The six reactors at Fukushima are housed in simple buildings designed to protect the pressure vessels from the weather. A buildup of hydrogen gas in multiple reactors caused caused the roof to blow off several of the buildings. These buildings were never intended to provide full containment in the event of a serious accident or meltdown.
Palo Verde on the other hand, was designed and built to higher standards. Each of the three reactors are protected by an airtight, reinforced-concrete containment building with 4 foot-thick walls. This extra level of protection was designed to contain the reactor and its contents in the event of a worst-case scenario: the direct impact of a jet airliner.
Each of Palo Verde's reactors operates independently, and can be brought offline or online without affecting the other units. The crews who operate the plant are also subject to strict operating procedures by the Nuclear Regulatory Commission (NRC). Employees undergo training every few weeks, even if they have decades of experience.
From superior design and a myriad of safety systems and extensive employee training, I feel that Palo Verde Nuclear Generating Station is an extremely safe facility run by professionals. I am not at all worried about the possibility of a Fukushima-style accident occurring here in Arizona, and you shouldn't be either.