The Fukushima Daiichi nuclear disaster, which took place in March 2011, delivered a reminder to the world that nuclear power comes with inherent risks. Over a period of several days, three Japanese nuclear reactors suffered meltdowns. A large amount of radioactive material escaped into the environment over the ensuing months.

Among the risks demonstrated by the Fukushima crisis is the threat of water contamination – including contamination of drinking water supplies by radioactive material. In the wake of the Fukushima accident, drinking water sources as far as 130 miles from the plant were contaminated with radioactive iodine, prompting cities such as Tokyo to warn against consumption of the water by infants.

In the United States, 49 million Americans receive their drinking water from surface sources located within 50 miles of an active nuclear power plant – inside the boundary the Nuclear Regulatory Commission uses to assess risk to food and water supplies.

Airborne contamination in the wake of a nuclear accident is not the only threat nuclear power poses to water supplies. Leakage of radioactive material into groundwater is a common occurrence at U.S. nuclear power plants, even if the amount of radioactivity released is tiny compared to that released at Fukushima. In addition, U.S. nuclear power plants draw their cooling water supplies from critical waterways nationwide – making those water supplies the natural destination for spilled or dumped radioactive liquid, and putting them at risk of contamination in a Fukushima-type accident.

Because of the inherent risks of nuclear power, the United States should ensure that all currently operating nuclear power plants are, at the latest, retired at the end of their operating licenses and the nation should move toward cleaner, safer solutions such as energy efficiency and renewable energy for our future energy needs.

The Fukushima nuclear accident contaminated a large area, and threatened drinking water over an even larger area.

• The Japanese government required residents of communities within 12.4 miles (20 kilometers) of the plant to evacuate, and encouraged voluntary evacuation for residents within 18.6 miles (30 kilometers (km)) of the plant.
• The U.S. government urged its citizens to leave areas within 50 miles of the plant.
• Months after the accident, citizens continue to find “hotspots” of radiation outside the evacuation zone. The Japanese government has evacuated some areas outside the initial evacuation boundary. Many areas within the boundary may be uninhabitable for decades.
• Airborne radiation contaminated drinking water supplies outside the evacuation zone, including 130 miles away in Tokyo. The village of Iitate, 28 miles from the plant, kept a warning in place regarding drinking water consumption through May 10.
• A large amount of radioactive water escaped into the ocean, through leaks and the dumping of 11,500 tons of seawater that was used to cool the reactor during the emergency.

According to data from the U.S. Environmental Protection Agency, Americans in 35 states drink water from sources within 50 miles of nuclear power plants. New York has the most residents drawing their drinking water from sources near power plants, with the residents of New York City and its environs making up most of the total. Pennsylvania has the second most, including residents of Philadelphia, Pittsburgh, and Harrisburg.

Table ES-1: Top 10 States by Population Relying on Water Intakes within 50 Miles of Nuclear Plants

The Indian Point plant in New York is close to the water supplies of the greatest number of people; 11 million New York, Connecticut, and New Jersey residents drink water from sources near the plant. Twenty-one different nuclear plants sit within 50 miles of the drinking water sources serving more than 1 million people. Of these plants, six share the same General Electric Mark I design as the crippled reactors at Fukushima.

Table ES-2: Top 10 Plants by Population Receiving Drinking Water from Intakes within 50 Miles

(Italics indicate reactors with GE Mark I containments.)

A total of 12 million Americans draw their drinking water from sources within 12.4 miles (20 km) of a nuclear plant. All land within 20 km of the Fukushima Daiichi plant has been mandatorily evacuated to protect the public from exposure to radiation. Some areas within, and even outside, that radius may remain uninhabitable for decades.

Table ES-3: Top 10 Plants by Population Receiving Drinking Water from Intakes within 12.4 Miles (20 km)

Major cities, including New York, Boston, Philadelphia, San Diego, Cleveland and Detroit receive their drinking water from sources within 50 miles of a nuclear plant. New York City receives its drinking water from within 20 km of the Indian Point nuclear station.

Table ES-4: Largest Water Systems with Intakes within 50 Miles of Nuclear Plants

Table ES-5: Largest Water Systems with Intakes within 12.4 Miles (20 km) of Nuclear Plants

Water contamination is not only a threat in the event of a major nuclear accident. 75 percent of U.S. nuclear plants have leaked tritium, a radioactive form of hydrogen that can cause cancer and genetic defects. Tritium can contaminate groundwater and drinking water, and has been found at levels exceeding federal drinking water standards near U.S. nuclear power plants.

• A tritium leak from the spent fuel pool at New York’s Indian Point Energy Center, discovered in 2005, went undetected long enough for radioactive water to reach the Hudson River.
• Tritium leaking from underground pipes at Braidwood Nuclear Generating Station in Illinois reached nearby drinking water wells; the leak was discovered in fall 2005.

The Fukushima nuclear reactor used seawater as a source of emergency cooling for the stricken reactors, with large releases of radioactivity to the Pacific Ocean. U.S. nuclear reactors draw their cooling water from a variety of important waterways, including:

• The Atlantic and Pacific oceans and the Gulf of Mexico.
• Three of the five Great Lakes (Michigan, Erie and Ontario).
• Key inland waterways such as the Mississippi, Ohio, Delaware, Columbia, Susquehanna and Missouri rivers.

The inherent risks posed by nuclear power suggest that the United States should move to a future without nuclear power.

The nation should:

• Retire existing nuclear power plants, at the latest, at the end of their current operating licenses.
• Abandon plans for new nuclear power plants.
• Adopt policies to expand energy efficiency and production of energy from clean, renewable sources such as wind and solar power.

In the meantime, the United States should reduce the risks nuclear power poses to water supplies by:

• Completing a thorough safety review of U.S. nuclear power plants and requiring plant operators to implement recommended changes immediately.
• Ensuring that emergency plans account for the potential impacts of drinking water contamination to residents outside the current 50-mile boundary used in planning.
• Requiring nuclear plant operators to implement regular groundwater tests in order to catch tritium leaks.
• Enforcing laws against tritium leaks by fining plant operators for unauthorized releases of radioactive materials.
• Require that nuclear waste be stored as safely as possible, preferably by using hardened dry cask storage (which reduces the risk associated with spent fuel pools).
• Requiring plants to take steps – such as construction of on-site storage capacity for contaminated water – to prevent the release of radioactive water in the event of an accident. Plant operators should have a plan to contain the amount of water that they anticipate using to flood the reactor in a worst-case scenario.