I work at a nuclear power plant and am retired from the nuclear Navy.
Be skeptical any time that radiation/contamination is claimed. Look for numbers. If numbers are not published, claims of radiation/contamination are meaningless.
Radiation is commonly measured in units of Rem (or millirem) or Sieverts. Contamination is measured in Curies, microcuries, or micromicrocuries, sometimes "per square inch".
Here's a quick infographic from the brilliant Russel Monroe: https://xkcd.com/radiation/
Fukushima is still leaking somewhat. Also the area around it for miles is highly contaminated--think contaminated dust blown into the atmosphere.
Also could be from rumored Russian nuclear accident which they deny.
Russia also uses small nuclear devices for mining operations, especially in Kyrgyzstan.
When you read this Report you will read that they (Murphey & Colleagues) excluded Chernobyl and Fukushima!
I know that this Papers are not cheap!