Wednesday, March 23, 2011

16/03 FAQs on radioactivity exposure, safety

The Yomiuri Shimbun

The following are excerpts from an interview with International University of Health and Welfare Clinic's health care center chief Gen Suzuki about how those people who have been ordered by the government to evacuate can prevent bodily exposure to radioactive material following the hydrogen explosions at the reactors of Tokyo Electronic Power Co.'s Fukushima No. 1 nuclear power plant.

Question: What worries should people have concerning the hydrogen explosion?

Answer: The reactors were placed in reactor containment vessels and these were housed inside buildings. The explosions occurred when a very large amount of hydrogen--created when the reactors were cooled--filled the building. Radioactive substances, such as iodine and cesium, that leaked from the reactors when the explosions occurred dispersed.

Q: Exposure to radiation can occur through contact with radioactive substances?

A: Yes, that's right. If people undergo examinations such as a CT scan, they are exposed to minute amounts of radiation.

Regarding this situation, the substances that emit radiation--not the radiation itself--have dispersed in the surrounding areas. External radiation exposure occurs when particles attach to a person's clothes or skin. Internal radiation exposure occurs after radioactive materials are ingested or absorbed through a wound.

Q: Is it better to stay inside?

A: It depends on how much radioactive materials disperse. But it's better to stay inside to prevent any exposure. If you're asked to stay inside, it is advisable to close all windows and doors, and cut off the external air flow by turning off any ventilators.

Q: What should we do if we have to go outside and evacuate to a shelter?

A: It is advisable to cover up and wear clothes that do not expose the skin as much as possible. Wear a hat and cover your nose and mouth with a wet towel or a mask. When you arrive at your destination, you should first check with authorities if any radioactive materials have adhered to your clothes or skin. If radioactive contamination is confirmed, you must decontaminate yourself.

Q: How do we decontaminate ourselves?

A: Take off your clothes, use wet towels to wipe such substances off yourself or take a shower. Specialists will judge what action should be taken case-by-case based on each shelter's procedures or the level of contamination. The removed clothes should be put in a vinyl bag and tightly secured.

Q: What about being in contact with those who have undergone decontamination procedures?

A: There is no problem because radioactive substances have already been removed. People who have undergone decontamination procedures can resume carrying on as normal.

Q: What about food?

A: Food outside may have been exposed to radioactive substances. You can wash the food but it's better not to eat it at all. Food inside is perfectly okay.

Q: What do you recommend in rainy or snowy weather?

A: It's possible that rain and snow can contain radioactive substances so it is recommended people stay inside. If going outside is unavoidable, follow the same procedures when you are advised to evacuate to a shelter and try to reach your destination as quickly as possible.

Q: How can we determine the level of radiation exposure?

A: Collective measures are used to estimate the exposure levels such as analyzing chromosomes and symptoms, conducting a blood test and using a device to measure internal radiation exposure.

However, there are not many specialists who can perform chromosome analysis and measure internal radiation exposure, so it's not always possible to test individuals at their request. When the nuclear fuel-processing plant accident occurred in Tokaimura, Ibaraki Prefecture, in 1999, tests were given only to patients who had worked at the site, patients who had displayed serious symptoms and to residents who were highly suspected to be exposed to a certain radiation levels.

Other measures to estimate exposure levels are based on facts such as the distance from a nuclear power plant; where you were (inside or outside a building, and whether the building was built of wood or concrete); and when and where you moved. For safety's sake, it's recommended to record your movements.

(Mar. 16, 2011)

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