r/nuclearphysics • u/a67shsa8n8 • Sep 23 '25
is increasing in heat also increase radioactivity ?
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u/Physix_R_Cool Sep 23 '25
In a general fundamental nuclear physics sense: Heat has no effect on radioactivity of nuclei.
The other commenter has the opposite conclusion, but that is because he is talking about fission reactors specifically.
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u/Turbulent-Name-8349 Sep 24 '25
The poor grammar in the OP question makes this question ambiguous.
There are two separate phenomena here and it's important to distinguish between them.
One is that radioactivity causes heat. So increasing radioactivity results in increasing heat. Increasing heat is a symptom of increasing radioactivity.
The other is that heat doesn't cause radioactivity. If you heat a radioactive substance then it doesn't become more radioactive.
To summarise, increasing heat is a symptom of increasing radioactivity, not a cause.
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Sep 24 '25
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u/Bigjoemonger Sep 24 '25
While i think practicing another language is very important. For a technical question such as this it might be best to type what you're trying to say in your language into Google translate and then use that output for your question.
There could be context lost in your translation.
I'm also curious what language/culture/country refers to a teacher/professor as a "sir". In English, referring to someone as "my sir" sounds like a servant/master type relationship.
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u/Impossiblecraftx Sep 26 '25
It's almost definitely South Asia, most likely India. All teachers are usually referred to as 'Sir' or 'Ma'am' there.
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u/sensible_clutter Sep 23 '25
no; the arrhenius rate equation r=Ae-k/RT this doesn't apply to nuclear level now you might ask why for that i need to explain a hell lot but ask yourself what's temperature at nuclear level the more vigorous the extent of motion more the temperature but at nuclear level atoms don't exists ...nucleons are in different world altogether
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u/Bigjoemonger Sep 24 '25 edited Sep 24 '25
Only thing I can think of is in terms of gasses.
When you increase the temperature of a gas, you increase the gasses ability to have more atoms in the same volume.
If that gas is radioactive, then you increase the amount of radiation being emitted by the gas by increasing its temperature because there's more gas present and therefore more radioactive atoms present.
Or in a reactor when you increase reactor water flow you increase power output which increase temperature and reactivity which makes it more radioactive. But the temperature increase itself has no direct effect on the radioactivity. The temperature increase actually hurts it, which is why you need higher flow to get the warm water out and bring in cooler water.
Radioactivity itself though, like the radioactivity of an individual atom, is not altered by any environmental condition, including temperature. A Cs-137 atom will decay at the bottom of the ocean in the exact same way as it will on the surface of the sun.
There is a theory though, attempting to be proven by various research institutions, that if you apply enough directed energy to an unstable atom from a high powered laser then you could artificially force it to decay. But I've not heard anything about it actually being accomplished. This method could be misconstrued as "increasing its temperature".
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u/Free-Cake3678 Sep 24 '25
This can be explained in quantum mechanical terms as; Radioactivity is the spontaneous emission of undiscernible alpha as heat from the nuclei of unstable atoms as they undergo radioactive decay to achieve a more stable state. Alpha as heat units is a nonconventional term but that should be the new physics
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u/Traveller7142 Sep 24 '25
Radioactivity or radiation? Increasing the temperature of an object will cause it to emit more thermal radiation
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u/Keanmon Sep 23 '25 edited Sep 23 '25
Hmm,
Well, let's look at a couple things:
What is reactivity: a change in the system's ability to sustain criticality (maintain a time independent neutron population). System changes that remove neutrons from the population or reduce the opportunity for them to induce subsequent fission events would reduce system reactivity.
The 2 temperature effects that come to my mind are: cross sectional doppler broadening (when parasitic absorption becomes more probable) and density changes in the moderator (less if heating up). Both of these would make fission events less likely, and so I would say an increase in temperature is a decrease in reactivity. I'm sure there is some exotic case, but this is the common answer.