Radiation Spread from Japan’s Nuclear Crisis Deemed of Minimal Risk to USA, Say Authorities

Key Takeaways:

• Experts affirm that the likelihood of radiation from Japan’s nuclear crisis reaching North America is extremely low due to the substantial distance between the two locations.
• Radiation from Japan would significantly dilute during transit, and any heavier radiation particles would naturally descend from a radioactive cloud before reaching the United States.
• Even in worst-case scenarios similar to the Chernobyl disaster, the diluted radiation levels reaching the United States would be no stronger than normal background radiation.
• The Nuclear Regulatory Commission states that current weather conditions have driven the radiation releases from the Fukushima reactors into the sea, away from populated areas.
• However, alternate views highlight the implications of a possible reactor meltdown, stating that the extent of radiation distribution in such circumstances is still uncertain.

Residual waves from the tsunami that critically damaged Japan’s nuclear facility eventually hit the American coastline, however, specialists affirm that the probability of any radiation from the Pacific Ocean crisis reaching North America is extremely low.

There is nearly no chance of any radioactive cloud making it as far as the United States, explains Jacqueline Williams, who is the program director for radiation medicine at the University of Rochester Medical Center’s Center for Biophysical Assessment and Risk Management Following Irradiation. “Although the situation in Japan is dynamic, there seems very little cause for concern,” she adds.

Radiation Levels

By the time radiation levels released in Japan reach the U.S., they would be greatly weakened, concurs Barry Rosenstein, a professor specializing in radiation oncology at Mt. Sinai School of Medicine. The simple explanation is the significant distance between Japan and North America, he suggests.

The extensive amounts of radiation that have escaped from Japan’s compromised reactors would need to traverse through air over 5,000 miles to reach North America. Williams argues that during such transit, any airborne radioactivity would disperse and thereby significantly dilute.

The dilution factor, whether via water or air, means it won’t impact anyone here, she confirms. Williams holds this opinion even under worst-case scenarios similar to the Chernobyl disaster, where a significant amount of radioactivity was unleashed.

Background Radiation

Additionally, heavier radiation particles would naturally descend from a radioactive cloud. This means that by the time any such cloud reached the United States, its radiation levels would be no stronger than normal background radiation that we are exposed to daily from Earth-based sources, atmospheric solar rays, and even drinking water.

However, the scenario in the United States may need reassessment if the crisis in Japan reaches catastrophic levels, warns Rosenstein.

Rosenstein refers to the massive release of radioactive isotopes during the Chernobyl incident, which significantly influenced a large part of Europe, well beyond the area surrounding Chernobyl itself. However, Europe and Ukraine are much closer in proximity than Japan is to the United States, even accounting for Alaska or Hawaii.

For now, Rothstein affirms, there is no concern about harmful radiation effects on the American side of the Pacific Ocean.

Nuclear Agency Input

The Nuclear Regulatory Commission agrees, stating that available data indicate that “weather conditions have driven the small releases from the Fukushima reactors into the sea, away from populated areas. Given the wide expanse between the two nations, Hawaii, Alaska, the U.S. Territories, and the U.S. West Coast are not projected to encounter harmful levels of radioactivity,” as per the agency’s website.

Alternate Opinion

However, not all views promote the same level of calm. Dr. Ira Helfand, nuclear safety specialist and the past president of Physicians for Social Responsibility, highlights the severe implications of a possible reactor meltdown if the containment vessel was breached and superheated fuel mixed with the water coolant.

“Each reactor holds vast amounts of radioactive materials — one reactor alone could release more radiation than 1,000 Hiroshima-style bombs,” states Helfand. According to him, it’s unclear how far radiation from such an event would travel or what potential medical threats it could pose.

“At Chernobyl, radiation spread over vast sections of Europe, and substantial regions up to 100 miles downwind had to be evacuated”, he points out. “However, the circumstances of that event were somewhat different, and we are uncertain about the extent of radiation distribution in the current situation.”

Japan Situation Update

In the wake of increased radiation detection, Japanese authorities temporarily withdrew emergency workers from the Fukushima Dai-ichi nuclear complex. Meanwhile, since last Friday’s catastrophic tsunami, which disabled the plant’s cooling systems and standby generators, an estimated 11,000 people are documented as dead or missing. Most officials project that the final fatalities, a direct result of the earthquake and tsunami, will overreach 10,000 people.

Further Information

For increased understanding of the risks related to nuclear radiation, please visit the University of Pittsburgh.