VietNamNet Bridge – Japan on April 12 raised the severity level of the accident at the crippled Fukushima No.1 nuclear power plant to 7, the worst on an international scale but in Vietnam, radioactive isotope level is very low, which is harmless to health.

The ranking has only been applied to the 1986 Chernobyl accident. According to Japan's Nuclear and Industrial Safety Agency, the amount of radiation emissions released at the Fukushima plant was equivalent to 10 percent of that in the Chernobyl accident.

The International Atomic Energy Agency described an accident ranked 7 as a major one. Level 7 is used to describe an event comprising "a major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures," according to an IAEA statement.

The Japanese nuclear safety authority has estimated that the amount of radioactive material released from the Fukushima No.1 plant to the atmosphere is approximately 10 percent of the Chernobyl accident.

Minoru Oogoda, an official with the Japanese agency, said the agency made the decision because the impact of radiation leaks had widely spread to the air, vegetables, tap water and the ocean.

“Japan’s announcement doesn’t mean that the accident has become more serious than yesterday, it is just re-evaluation of the actual situation of the accident,” said a report of the Vietnamese Ministry of Science and Technology.

Dr. Dang Thanh Luong, Vice Chief of the Vietnam Nuclear Radioactive Safety Agency, said that although Japan has raised the severity level of the accident at the Fukushima No.1 plant, the crisis is quite different from the 1986 Chernobyl accident.

While the Chernobyl accident involved an explosion at the reactor core, and the resulting fire and vapors drove a large quantity of radioactive material into the air and surrounding areas, explosions at Fukushima No.1 plant happened outside the pressure vessel which contains the reactor core.

“Japan raised the severity level of the accident to reflect the seriousness of the accident, not to reflect the current situation,” Dr. Luong said.

According to the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), the radioactive cloud still spreads to the entire northern hemisphere, including Vietnam. However, the radioactive level is very small and the people don’t need to be worried.

Observing stations in Vietnam have detected radioactive isotopes I-131, Cs-134 and Cs-137 in Lang Son in the north, Da Lat (Lam Dong province) and Ninh Thuan in the central region and HCM City, but the concentration is reducing.

An observing station recently detected radiation in pine needles and rain water in Hanoi but the level is very small, and not dangerous to humans.

PV