Nuclear emergency personnel (or liquidator , the name given to each of the approximately 600,000 people who worked to minimize the consequences of the nuclear disaster of April 30, 1986 in Chernobyl) can receive very high radiation doses. . Some members of the nuclear emergency personnel received up to 100 millisieverts (mSv).
Workers have an annual limit of 20 mSv. Until recently it could be as high as 50 mSv, as long as 100 mSv is not exceeded in 5 years. However, in the plants we have a limit of 10 mSv / year. In the event of an accident, the CSN could agree to exceed the 20 mSv limit as long as the benefit of the action justifies it […] I would not authorize an exposure of 100 mSv if not for a very extreme situation.
On Earth, an ordinary person receives an annual radiation dose of one mSv, while an astronaut on the International Space Station can receive 220 mSv in a whole year, that is, higher than that of nuclear emergency personnel in case punctual.
Radiation from astronauts, too, can be increased by other factors, in addition to being outside the protection offered by the Earth’s atmosphere. The severe solar flares that occur once every 11 years increase the radiation dose in the orbiting complex tenfold, according to the head of the Department of Radiation Safety of Russian Manned Spaceflight , Viacheslav Shurshakov :
During the eruptions we used to ask the crew of the Mir orbital station (which operated from 1986 to 2001) to move the berths from the cabins to the central station, since that place is the most protected from radiation: the dose is three times lower than in the cabin. Same thing on the Space Station.
The sievert is intended to represent stochastic health risk, which for radiation dose assessment is defined as the probability of radiation-induced cancer and genetic damage. A sievert carries with it a 5.5% chance of developing cancer based on the no-threshold linear model .
In space travel, and because there is radiation in space from the solar wind and cosmic rays, NASA has the rule that in 10 years of service, an astronaut should not receive more radiation than it would increase 3% the probability of suffering a fatal cancer in the future .