# Misunderstanding of numerical value of radiation of reported nuclear accident

In the report of the newspaper, the value of the radiation of strength of the radiation of the nuclear accident and an X-ray mass screening and the value that a general person bathes in from the natural world in year are compared. To begin with, because the unit is different, it is wrong to compare this.

## The report of the newspaper and the television confuses doses of radiation with strength of the radiation.

An important nuclear accident occurred with "Tohoku Great Kanto Earthquake" on March 11, 2011 in the first nuclear plant in Fukushima Japan. The radioactive substance is supposed to leak, and to save it in 20km or more in the radius. In addition, the sheltering is scheduled in radius 20km-30km district.

From nuclear power plant to measurements of radiation on the 16th according to the Yomiuri Shimbun morning newspaper March 18, and 14.2-80 [μSv/h] in point of 30-40km .And, it was 4.0-22.2 [μSv/h] in the point of 50-60km. Moreover, it was 170 [μSv/h] in measurements the 17th.

It expresses it in the report of the newspaper as follows. The amount of one radiation of an X-ray mass screening of the chest is 50 [μSv]. The value of an X-ray mass screening of the stomach is 600 [μSv]. The value that a general person receives from the natural world in year is 2400 [μSv]. The value of one time of the chest CT scan is 6900 [μSv]. Numerical values of the radioactivity of this value and the nuclear accident are compared with the newspaper. To begin with, because the unit is different, it is wrong to compare this.

## Mistake of press report

In the report of the newspaper, strength of the radiation measured from the nuclear power plant in 30km separated place was 170 [μSv/h]. This value and the value (2400[μSv]) that a general person receives from the natural world in year are compared. Therefore, the value of the radiation is low, and the impression without the problem is given. This cheats a general person.

### It is necessary to arrange the unit to compare it.

If the unit is not arranged if it compares it, it is not significant. The unit is arranged in [μSv/h] of micro sievert/hour and it sees. Then, when value (2400[μSv]) that a general person bathes in from the natural world in year is converted into the hit during one hour, it becomes 0.27[μSv/h].

## 170[μSv/h] It is very dangerous.

This increases to 630 times that of the natural world very much if this is compared with value 0.27[μSv/h] that a general person bathes in from the natural world because the value measured on March 17, 2011 is 170[μSv/h].

If the radiation of 170[μSv/h] is bathed in for one year, it becomes about as many as 1.5 sieverts [Sv]. This is stronger than one sievert that causes the acute radiation damage, and causes becoming turbid of the evil intention, vomiting, and the crystalline lens etc. , that is, bathe in in short course. Moreover, it is a level that the person of 5% dies in two sieverts.

## Do you receive an X-ray mass screening of the chest as many as 80 times a day?

170[μSv/h] of the value measured is compared with value (50[μSv]) of an X-ray mass screening of the chest. This is same thing of the chest as receiving an X-ray mass screening every 18 minutes. Do you want to receive an X-ray mass screening so frequently?An X-ray mass screening of the chest was received as many as 80 times when was in this place during a day.

## Exposed dose[Sv] and strength of radiation[Sv/h]

### The sievert is a unit that shows exposed dose [Sv] to the living body.

Sievert is a unit that shows the exposed dose to the living body. The sievert is gross weight of the radiation that the living body of exposed dose received, and no ,in a word, strength of the radiation.

### The exposed dose each unit time shows strength [Sv/h] of the radiation.

The sievert each unit time is used for showing strength of the radiation to the living body. The unit is shown by the exposed dose an hour like [Sv/h]. However, the exposed dose an hour should be only called a sievert, and it note it in the report such as the televisions because it is likely to use it as strength of the radiation.

When strength of the radiation is discussed, the CT inspection one-radiation exposure dose and the exposed dose when taking a picture of X rays of the stomach are used well. Because compared units are different, this cannot be simply compared.

The amount of the natural radiation that our living body receives will be called 2.4 millisieverts in one year of the all parts of the world average. This corresponds to radiation strength 0.27[μSv/h].

### Symptom of amount of radiation exposure and human body received in short course

150 millisieverts = man temporarily becomes infertility.

250 millisieverts = white blood corpuscles decreases.

500 millisieverts = lymphocytes decreases.

1 sievert = acute radiation damage happens. Becoming turbid of evil intention, vomiting, and crystalline lens etc.

2 sieverts = The person of 5% dies.

4 sieverts = The person of 50% dies.

7 sieverts = The person of 100% dies.

### Exposure in medical institution

The radiation exposure dose when the CT inspection is undergone once in the hospital is about 7 millisieverts. There is an exposure of 0.5-3 millisieverts in the X rays taking a picture of the stomach. There is an exposure of about 50 micro sievert [μSv] one time of an X-ray mass screening of the chest.