What is the origin and meaning of “3.6 roentgen, not great, not terrible”?


What is the origin and meaning of “3.6 roentgen, not great, not terrible”?

In: Physics

It was in the miniseries *Chernobyl*. It was said by a character who was obstinately refusing to consider the possibility that the disaster was worse than it was. 3.6 roentgen was the maximum that the sensor that they had available could read, which meant that the real value was likely to be higher. Spoiler: it was.

I don’t know if it’s reported that the real person that the character was based on said something like that in reality or not.

It’s from the HBO series *Chernobyl*. At first the engineers in the nuclear plant thought that the radiation was leaking at a rate of 3.6 roentgen per hour, which is apparently higher than normal but not catastrophic. It was days before they found out that it was actually in the tens of thousands of roentgen per hour.

It comes from the TV series *Chernobyl* about the nuclear disaster.
A roentgen is a measurement of exposure to ionizing radiation.
3.6 roentgen was the maximum the standard issue meter would show. Good enough to tell you you should get out of the area, but not enough to tell you just how bad a radiation disaster was.
It was said by a character to show he was making everything worse.

Also note, we stopped using roentgen as a unit.
We now prefer grays (a measure of how much radiation is absorbed as opposed to how much radiation was just “there”), or sieverts(a measurement of radiation’s effect on a human body).

A Roentgen is a unit of radiation exposure named after Willhelm Roentgen, a German scientist who discovered the x-ray.

By US federal regulations radiation workers aren’t allowed to be exposed to more than 5 rem (Roentgen Equivalent Man) per year.

So Roentgen is basically exposure through air, rem is how much of that exposure is actually absorbed by the body.

The primary concern with chernobyl was gamma rays which have a multiplying factor of 1, therefore Roentgen to rem is roughly 1 to 1 so we can roughly correlate 3.6 Roentgen to 3.6 rem.

So the rule is 5 rem per year and they were being exposed to 3.6 rem per hour.

The reason he said “not great not terrible” is that at 3.6 rem per hour you can still get emergency work done as long as you only spend a few minutes in the radiation field. And open exposure to the core could have dose rates at hundreds to thousands of rem per hour.

So it wasn’t a great dose rate to be working in but could have been much worse, little did he know it actually was much worse.

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