Radioactive Threat Real in Japan: What to Know

The radiation levels at Japan’s Fukushima Dai-ichi nuclear power plant continue to fluctuate. Overnight, the spike in radiation levels forced the remaining workers out of the plant for a short time. Police are planning to use water cannons normally reserved for crowd control to keep nuclear fuel rods submerged in water.

When those rods burn off the water which turns to steam and escapes the compromised reactor container that’s when radioactive material gets into the atmosphere.

The Fukushima Dai-ichi power plant is not just one nuclear reactor. The whole site is made of six reactors and they all appear to have been damaged after the March 11 9.0 earthquake and tsunami. While the Japanese power plants were built to handle an 8.5 quake and large tsunami this mega quake just dwarfed what the plant can handle.

Timeline of Events
Shortly after the earthquake Japan declared a nuclear emergency when some of the automatic cooling procedures failed. Within hours, power plant workers released low level radioactive steam in an effort to cool the overheating unit 1 reactor.

On March 12, four workers were injured when the built up heat and pressure inside the unit 1 reactor containment building exploded. This hydrogen explosion destroyed part of the outer building but left the nuclear core intact, though compromised and heating up.

Then two days later unit 3 exploded. The outer building was destroyed but the reactor was not breached. Japanese officials reported this explosion as another hydrogen explosion caused by a build up of heat and pressure from the overheating reactor.

In the evening of March 14, officials reported that the unit 2 reactor was intact but that fuel rods had been exposed to air still within the intact containment vessel and therefore not exposed to the outer atmosphere.

Fuel rods are submerged in freshwater to keep them cool. Tokyo Electric Power Company (TEPCO), the company that operates the nuclear power plant says that an airflow gauge was accidentally turned off. When that happens, water can’t flow into the reactor. As the water boils off from the heat of the fuel rods the rods are left high and dry, which puts them at risk to begin melting.

Then on March 15 a third explosion rocked the Fukushima 1 power station. This time the roof blew off of unit 4, which was believed to have been damaged when unit 3 exploded.

At the same time, radiation spiked from unit 2 where Japanese officials thought the rods had begun melting after the pressure-suppression system was likely damaged.

Later that morning, unit 4 caught fire. Again radiation levels spiked, indicating that nuclear material was escaping into the atmosphere. The International Atomic Energy Agency said the fire was at a spent fuel pond and it took about three hours to extinguish, during which time all remaining nuclear power plant workers were evacuated.

Since then, radiation levels have spiked and dropped. Unit 4 caught fire again. Then unit 3 began emitting what officials believe is radioactive steam from the damaged reactor. Workers planned to spray boric acid from a helicopter on the fuel rods to prevent the spent nuclear fuel rods from reaching criticality again and starting a nuclear chain reaction. But that plan was put on hold because radiation levels near the plant were too high.

Radiation Release
Plutonium, tritium, radioactive iodine, strontium and cesium are all the elements that are being discussed in association with the nuclear crisis at Fukushima Dai-ichi power plant in northeastern Japan.

When the quake struck, reactors 1, 2, and 3 were in service. Units 4, 5, and 6 were undergoing routine maintenance and were already offline. Unit 4 was fully de-fueled, meaning it didn’t contain a radioactive core. But all six reactors have spent fuel ponds, which became unstable after proper cooling procedures failed after the mammoth quake and resulting tsunami.

First, power plant workers released small amounts of steam containing tritium and cesium to relieve some pressure at unit 1. They did another small release for the same reason at unit 3.

Tritium is an istotope of hydrogen which easily bonds to air and water. It is what is called a low beta emitter, meaning it dangerous externally. Radiation risk only exists if inhaled or ingested in food or water or through absorption through the skin. Tritiated water breaks down in the human body in 7-12 days so therefore poses little risk of short term exposure if ingested and it won’t accumulate in the body over time.

Cesium is a heavy metal that has 39 different isotopes, ranging from 112 t0 151. Those numbers represent the atomic mass of the element. The most common radioactive isotope is cesium 137. It has a half-life of 30 years, meaning it will take that long to decay into the element barium.

Strontium 90 is another radioactive isotope associated with spent nuclear fuel rods. It is considered a “bone seeker” because it exhibits similar biochemical behavior to calcium, the main ingredient in bones. Strontium is generally taken in through contaminated food or water. About 70-80 percent of the strontium is expelled from the body with the rest being absorbed in bone and bone marrow That’s where concerns about heightened risk of leukemia or bone cancer originate. It’s half-life is also about 30 years.

With the growing concern about radioactivity leaking into the environment, concerned Japanese citizens and even people on the west coast of the U.S. have flocked to pharmacies to purchase potassium idodide pills to counteract any potential exposure to radioactive idodine. This isotope is 131. It has a half-life of 8 days.

Taking idodine tablets saturates the thyroid gland with iodine just before exposure to prevent radioactive idodine from getting into the gland and causing thyroid cancer. Taking the pills as a precaution is unnecessary if there is no immediate threat of radiation exposure. The pills will only protect people from absorbing idodine 131 for 24 hours.