High School Calculating safe levels of radioactivity

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SUMMARY

This discussion focuses on calculating the time required for radioactive elements, specifically Cesium-137, to decay to safe levels. The decay formula (N=No*e^(-kt)) and the half-life formula (K = ln2/t(1/2)) are essential for these calculations. Participants emphasize the importance of defining "safe" levels and understanding the initial activity (Bq) of the radioactive materials. The conversation highlights the complexities involved in estimating decay times based on varying environmental factors and the need for precise measurements of contamination levels.

PREREQUISITES
  • Understanding of radioactive decay formulas, specifically N=No*e^(-kt) and K = ln2/t(1/2)
  • Knowledge of activity measurement in Becquerels (Bq)
  • Familiarity with the concept of half-life in radioactive materials
  • Basic principles of radiobiology related to safe exposure levels
NEXT STEPS
  • Research the decay characteristics of Cesium-137 and its half-life of 30 years
  • Learn how to calculate activity levels in Bq from concentration measurements (e.g., kBq/m³ to Bq/g)
  • Investigate the effects of environmental factors on radioactive decay and contamination spread
  • Explore case studies of water contamination from nuclear incidents, such as Fukushima and Chernobyl
USEFUL FOR

Environmental scientists, radiobiologists, health physicists, and anyone involved in assessing and managing radioactive contamination risks.

  • #31
mfb said:
So what do you get for the activity per gram if you convert 1.8 kBq/m3 to Bq/g?
0.0018 Bq/g
 
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  • #32
Right. A factor 100 below the 0.2 Bq/g limit.
 
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  • #33
mfb said:
Right. A factor 100 below the 0.2 Bq/g limit.
...

Help

Please
 
  • #34
What? You figured out that all the reported values in this thread were below the safety limits all the time.

If you want to calculate some time, you'll need water with more contamination. Or take something else, e. g. mushrooms in Bavaria.
 
  • #35
mfb said:
What? You figured out that all the reported values in this thread were below the safety limits all the time.

If you want to calculate some time, you'll need water with more contamination. Or take something else, e. g. mushrooms in Bavaria.

OK. I have looked now at examples from Fukushima Daichii 2011, but they're reporting the levels to now be near identical to pre incidental levels. Considering this is the largest incident since Chernobyl, is it safe to assume there have been no other incidents where water contamination was worthy to investigate?

I am considering just making a scenario and analysing that.
 
  • #36
Water contamination is one of the first things to go down, simply because water flows away and carries the radioactivity away with it.

Mushrooms are more promising, they tend to accumulate some elements that have long-living radioisotopes.
 
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