After the discharge of
contaminated water >
< anchor, some consumers measure the radioactivity of seafood directly with a portable measuring instrument in case of worry. The number of companies selling portable meters is also growing rapidly, and fact-checking the fact that this meter will be effective has been checked in the corner.

I'm a journalist.


A video of a Chinese man measuring radiation while eating sushi in Tokyo, Japan, has recently gone viral.

Tokyo Electric Power Co. has said it removes cesium from contaminated water, but there is still mistrust.

In Korea, there are also many consumers who are wondering whether to buy or should buy a portable measuring instrument, and we experimented with the help of the Korea Institute of Standards and Science.

First, cesium was dissolved in water to produce a sample of 100 becquerels, which is the national food standard.

Next, I looked at the simple meter.

About 0.2 microsieverts per hour.

It's no different than when you measure in the air where there is nothing.

The same is true of the results measured with another simple meter.

[Hwang Sang-hoon, Head of Radiation Standards Group, Korea Institute of Standards and Science: There is no problem with the meter itself. I think we have shown that 100 becquerels do not have such significant (different) measurements from basal (airborne) radiation.]

Enlarge the image

This time, I made a sample of 100,1 becquerels, which is 0 times the reference value.

The measurement went up by 3.0 microsieverts per hour, or just 1.0.

If it's 3.10, that's one-tenth of the radiation dose you get when you're flying.

The standard value for food is set in becquerels, which is the number of radiation emitted per second, but portable measuring instruments usually measure in microsieverts, which quantifies the effect on the human body, which is why this discrepancy occurs.

For this reason, the Ministry of Food and Drug Safety and specialized organizations grind food into samples and accurately measure them with equipment using germanium semiconductors.

In addition, beta rays from the contaminated tritium are so penetrating that portable meters cannot measure them at all.

[Kim Ki-hyun, professor of nuclear engineering, Seoul National University: If there was tritium in the water that the fish drank, (beta rays) would have to penetrate the fish to measure something like this, but the fish would not be able to penetrate it.]

The common explanation among experts is that you don't have to buy a meter because of a vague anxiety about radiation.

(VJ: Kim Jun-ho, Video Editing: Yu Mira, Screen Source: Doo Woo-in)

▶ "Investigate until the people 'stop'"... Second discharge of contaminated water at the end of September