If you are referring to nuclear power plants and radioactive materials, then there is a high necessity to be cautious and stay safe because only by being safe you can prevent accidents like those caused in Ukraine and Japan. Unlike other types of power plants whose destruction in case of an accident can relatively easily be contained, nuclear power plants are extremely difficult to manage if things go out of hand since you can destroy the air around it, the water, the food by ruining the soil, and many other things.
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If the refrigerator has no room to cool the meat that you've just cooked, then you should clear it with other stuff or food that has not been consumed for days. There might be some goods that are not good for consumption anymore even though it has been placed in the ref for a couple of days. Hope this answers your question.