Concerns about radiation have led the United States government to urge its citizens within 50 miles of the reactors to evacuate. But President Barack Obama reiterated Thursday that Hawaii and other parts of the U.S. have little to fear.
Nevertheless, Civil Beat has compiled the questions we've heard people talking about and have been lobbing around the newsroom. We went to the experts to find out what's what. We'll add resources and more Q's and A's to this page as necessary. Here's what we've asked, and what's been answered so far:
What happens if one or more of Fukushima's nuclear reactors melts down?
"Meltdown is the loss of cooling to the reactor fuel rods such that they overheat," explains Rob Taylor, technical assistant in the Office of Public Affairs at the U.S. Nuclear Regulatory Commission.
The six nuclear reactors at Fukushima were successfully powered down after the magnitude 9.0 quake on March 11, but the cooling system that pumps water to prevent overheating failed. As the zirconium cladding melts and cracks from the heat, radioactive gas can be released, though other measures — the shell of the reactors and the containment buildings — may be in place to keep it from reaching the open atmosphere.
View the New York Times infographic that shows what happens in a meltdown.
Could explosions propel radioactive materials into the jet stream?
"Nuclear reactors do not explode. They are not designed that way," Taylor said.
Explosions seen in footage from Japan might well be from hydrogen, he said. And asked if hydrogen-fueled blasts might push radioactive materials into the jet stream, where they'd be pushed east at hundreds of miles an hour, Taylor said, "I don't want to speculate on what hydrogen might do."
A forecast of the path of the plume by the Comprehensive Nuclear Test Ban Treaty Organization shows that radiation could reach the mainland United States in less than a week. (Low levels of radiation have already reached northern California.) Taylor said the organization's model doesn't take into account the conditions at the site in Japan and thus doesn't specify how much radiation could be carried across the Pacific. The U.S. Department of Energy, which has done plume modeling for the Japanese reactor, did not return calls.
"The models that we've run and the analyses that we've performed do not show the radiation dispersing that way," he said.
"Given the thousands of miles between Japan and U.S. states and territories, we don't believe you can generate enough of a source term" — the total amount of radiation estimated to have been released into the environment — "to have radiation in harmful levels to affect people."
What are the types of radiation?
Everyone absorbs some background radiation, but not everyone is negatively affected by it.
Radiation poisoning — also known as acute radiation syndrome — is caused by very large doses of radiation, according to the Mayo Clinic. For radiation to have an adverse effect, large amounts need to be absorbed by breathing it in, ingesting it or absorbing it through open wounds.
There are three types of ionizing radiation. They include:
- Alpha Particles, which can be stopped by a piece of paper;
- Beta Particles, which can be stopped by clothing or plastic;
- Gamma Rays, which can be stopped by inches to feet of concrete, or less than an inch of lead.
Gamma Rays are what Hawaii should know about. Common sources include cesium, technetium and iodine.
Iodine, which many of us have heard about in media reports, has a half-life of eight days. Meaning, if radioactive particles were to somehow reach Hawaii after a week of sailing through the air, half of the particles would have stabilized before they arrived. The clock started ticking when the reactors were powered down, stopping the fission process.
What is radiation exposure?
Radiation exposure is when your body is penetrated by the energy emitted from radioactive material. Potentially more dangerous is radioactive contamination, which occurs when radioactive material is either on or in your body.
"A contaminated person is exposed to radiation released by the radioactive material on or inside the body," according to the Centers for Disease Control and Prevention. "An uncontaminated person can be exposed by being too close to radioactive material or a contaminated person, place or thing."
Radioactive materials released into the environment can contaminate air, water, surfaces, soil, plants, buildings, people and animals, according to the CDC.
- Radioactive Contamination and Radiation Exposure — Centers for Disease Control and Prevention
What are the effects of radiation?
General low-level doses of radiation to the entire body in a short time can cause nausea, vomiting, fatigue and diarrhea within hours.
High-level doses received in a short time can cause hair loss, and loss of appetite can occur within a week. Extremely high doses in a short time will likely lead to death within a few days or even hours.
The long-term effects of radiation exposure and contamination from radioactive material are a subject of great debate. However, the World Health Organization says exposure to radiation can cause cancer.
Widely-discussed long-term effects include:
- Cancer (especially thyroid cancer);
- Genetic mutations from damaged chromosomes
Radiation-induced leukemia takes at least two years to appear after exposure, according to the independent nonprofit Health Physics Society, a membership organization of more than 6,000 scientists and experts dealing with all aspects of radiation safety. Radiation-induced tumors take at least 10 years to appear. The increased risk from exposure can last for the rest of a person's life.
But exposure to radiation does not create a unique cancer risk situation, according to a report from the Health Physics Society.
"The risks of cancer are not directly measurable or distinguishable from the cancer risk caused by other sources (environmental, chemical, biological, etc.)," the report states.
- Health Effects and Treatment — CDC
- Acute Radiation Syndrome: A Fact Sheet for the Public — CDC
- Radiation Risk and Benefit Assessment — Health Physics Society
- Radiation Effects (PowerPoint) — Health Physics Society
- Radiation Sickness — The Mayo Clinic
- Radiation and Its Health Effects — United States Nuclear Regulatory Commission
- Biological Effects of Radiation — NRC
What populations are most vulnerable?
Young children, pregnant women and embryos are more sensitive to the effects of radiation.
- Radiation Effects (PowerPoint) — Health Physics Society
- Radiation and Pregnancy: A Fact Sheet for the Public — CDC
- Radiation Exposure and Pregnancy — Health Physics Society
How is radiation spread?
Radioactive contamination is spread through touching people or things that have radioactive material on their surfaces, or ingesting foods that have been contaminated.
People who are internally contaminated can expose people near them to radiation from the radioactive material inside their bodies. Body fluids of internally contaminated people also can contain radioactive materials, which can contaminate or expose others.
During the Chernobyl disaster in 1986, 28 people died within weeks as a result of acute poisoning. In many cases, food was tainted from radiation infecting soils.
- Radioactive Contamination and Radiation Exposure — CDC
- Oak Ridge Institute for Science and Education
What levels of radiation are dangerous?
Radiation exposure is often measured in rem.
People are exposed to radiation on a daily basis from various sources, including cosmic rays from outer space, the soil, dental X-rays and mammograms. The average person is exposed to an average of 310 millirem — or 0.31 rem — of naturally occurring radiation annually.
The effects of these radioactive materials are not enough to have a negative impact on the future health of most people.
Radiation becomes dangerous when received in doses of 100 rem or more within a short period of time. Half of people who receive between 300 and 500 rem in a short time will die if they don't receive medical attention, according to the Health Physics Society.
What preventative measures can people take?
The first thing to know is that local authorities are monitoring monitoring radiation levels. As of Thursday afternoon, March 17, no spikes in the levels have been detected. If levels do spike, they will recommend protective actions to take based on the amount of radiation detected.
In any case of emergency, the CDC recommends putting together an emergency kit including flashlights, batteries, water, non-perishable food and first aid materials.
If advised to shelter yourself, bring pets inside, close doors and windows and turn off air conditioners and fans that bring in air from the outside.
What are the treatment options?
According to the Mayo Clinic, the first phase of radiation treatment includes simple sanitation.
Steps to take include:
- Remove clothing and shoes
- Gently wash with soap and water
Decontamination tactics like these can prevent further distribution of radiation sickness and lowers the risk of internal contamination.
There are also certain medications that can be used. These include:
Potassium Iodide (KI) pills — These are nonradioactive forms of iodine. The thyroid gland is a potential destination for iodine in the body. If there is internal contamination from radioactive iodine, the thyroid can absorb it just like it would normal iodine. With KI pills, the thyroid is saturated with iodine so there is no more room for it to absorb radioactive iodine, should you breathe it in. Instead, the radioactive iodine is cleared from the body through urine.
For KI pills specifically, the Health Physics Society says: If taken either before or very soon after a radioactive iodine intake and if taken in the proper dose, it will block the uptake of radioactive iodine by the thyroid. KI can be in the form of a pill or a supersaturated solution. The recommended daily dosage for an adult is 130 milligrams. If the thyroid absorbs all the iodine that it needs from non radioactive KI, then the radioactive iodine will not be absorbed and will be eliminated from the body mostly by way of the urine.
Prussian Blue — This is a dye that binds radioactive particles like cesium and thallium. Once bound, the particles are excreted in feces. Prussian Blue essentially speeds up the elimination process for radioactive particles and reduces how much radiation cells can absorb.
Diethylenetriamine Pentaacetic Acid — This binds metals together. Radioactive elements like plutonium, americium and curium can bind when using the acid. They are then eliminated by urinating.
For information about KI pills for infants, pregnant women, children, young adults and breastfeeding women, refer to the Centers for Disease Control and Prevention.
- Potassium Iodide (KI) — CDC
- Use of Potassium Iodide — Health Physics Society
- Fact Sheet: Prussian Blue — CDC
- DTPA — CDC
- Neupogen — CDC
- Radiation Treatments and Drugs