Buy / Sell / Trade Thread Rules

Thread will be archived and replaced at the start of every month.

On October 1, 2026 this thread will be archived and replaced!

• All listings must be posted as comments in this thread. Standalone buy, sell, or trade posts will be removed.
• Only list items that you personally own. Do not post listings on behalf of another person, business, or shop.
• Every listing must include proof that the item is radioactive. A photo showing the item with a Geiger counter or spectrometer reading above background is sufficient. If your selling platform (such as eBay or Etsy) does not allow references to radioactivity, you may post the verification as a reply to your listing instead.
• Listings without verification will be removed.
• Create a separate top-level comment for each item you are listing. There is no limit to the number of listings you may post.
• Each item may only be listed once per thread. If it does not sell, you may repost it when a new Buy / Sell / Trade thread is created.
• Once your item has sold or is no longer available, please edit your comment to indicate its status.
• This thread is for all legal radioactive items. Do not list any item that is illegal to possess, sell, or ship in your jurisdiction. 
• If you are unsure whether an item is radioactive, do not list it until you have confirmed it.
• Buyers and sellers are expected to be familiar with safe handling and applicable shipping regulations. It is your responsibility to ensure that any item you ship can be transported safely and legally.
• For any questions you have, please message u/OkPick296

Disclaimer

The moderators of r/Radioactivestuff  are not responsible for transactions conducted through this subreddit and cannot guarantee the honesty of buyers or sellers. Please use caution and common sense when buying, selling, or trading online.

While the moderation team will not mediate disputes, we do take reports of fraud and intentional misrepresentation seriously. If you have a negative experience with a buyer or seller, please report it to the moderators. Users found to be scamming others or deliberately misrepresenting items will be permanently banned from the subreddit.

Buy / Sell / Trade Thread Rules

Thread will be archived and replaced at the 20th of every month.

On October 20th, 2026 this thread will be archived and replaced!

• All listings must be posted as comments in this thread. Standalone buy, sell, or trade posts will be removed.
• Only list items that you personally own. Do not post listings on behalf of another person, business, or shop.
• Every listing must include proof that the item is radioactive. A photo showing the item with a Geiger counter or spectrometer reading above background is sufficient. If your selling platform (such as eBay or Etsy) does not allow references to radioactivity, you may post the verification as a reply to your listing instead.
• Listings without verification will be removed.
• Create a separate top-level comment for each item you are listing. There is no limit to the number of listings you may post.
• Each item may only be listed once per thread. If it does not sell, you may repost it when a new Buy / Sell / Trade thread is created.
• Once your item has sold or is no longer available, please edit your comment to indicate its status.
• This thread is for all legal radioactive items. Do not list any item that is illegal to possess, sell, or ship in your jurisdiction. 
• If you are unsure whether an item is radioactive, do not list it until you have confirmed it.
• Buyers and sellers are expected to be familiar with safe handling and applicable shipping regulations. It is your responsibility to ensure that any item you ship can be transported safely and legally.
• For any questions you have, please message u/OkPick296

Disclaimer

The moderators of r/Radioactivestuff  are not responsible for transactions conducted through this subreddit and cannot guarantee the honesty of buyers or sellers. Please use caution and common sense when buying, selling, or trading online.

While the moderation team will not mediate disputes, we do take reports of fraud and intentional misrepresentation seriously. If you have a negative experience with a buyer or seller, please report it to the moderators. Users found to be scamming others or deliberately misrepresenting items will be permanently banned from the subreddit.

r/Radioactivestuff

Buy / Sell / Trade Thread Rules

Buy, sell, and trade radioactive materials, radiation detection equipment (Geiger counters, scintillation detectors, dosimeters, spectrometers, survey meters, etc.), and other radiation-related items on r/Radioactivestuff!

This thread is archived and replaced on the 20th of every month.
On August 20, 2026, this thread will be archived and replaced.

Listing Rules

• All listings must be posted as comments in this thread. Standalone buy, sell, or trade posts will be removed.
• Only list items that you personally own. Do not post listings on behalf of another person, business, or shop.
• Create a separate top-level comment for each item. There is no limit to the number of listings you may post.
• Each item may only be listed once per thread. If it does not sell, you may repost it when a new Buy / Sell / Trade thread is created.
• Once your item has sold or is no longer available, edit your comment to indicate its status.

Verification Requirements

Radioactive Materials

Every listing for a radioactive item must include proof that the item is radioactive. A photo showing the item alongside a Geiger counter, spectrometer, or other suitable radiation detector with a reading above background is sufficient.

If your selling platform (such as eBay or Etsy) does not allow references to radioactivity, you may post the verification as a reply to your listing instead.

Listings for radioactive items without verification will be removed.

Photos of the radioactive materials must represent the material's condition and quality.

Radiation Detection Equipment

Listings for Geiger counters, scintillation detectors, dosimeters, spectrometers, survey meters, or other radiation detection equipment must include proof that the equipment is functional. Acceptable verification includes:

• A photo showing the device detecting background or a radioactive source. (Videos are strongly encouraged, though not necessary)
• The photos of the device should represent the condition and quality.

Listings for non-functioning equipment must clearly state that the item is for parts, repair, or restoration.

Legal & Safety

• This thread is for all legal radioactive items and radiation-related equipment. Do not list anything that is illegal to possess, sell, or ship in your jurisdiction.
• If you are unsure whether an item is radioactive, do not list it until you have confirmed it.
• Buyers and sellers are expected to be familiar with safe handling practices and applicable shipping regulations. It is your responsibility to ensure that any item you ship can be transported safely and legally.

Questions

If you have any questions, please message u/OkPick296.

Disclaimer

The moderators of r/Radioactivestuff are not responsible for transactions conducted through this subreddit and cannot guarantee the honesty of buyers or sellers. Please use caution and common sense when buying, selling, or trading online.

While the moderation team will not mediate disputes, we do take reports of fraud and intentional misrepresentation seriously. If you have a negative experience with a buyer or seller, please report it to the moderators. Users found to be scamming others or deliberately misrepresenting items will be permanently banned from the subreddit.

That was stupid

Most (not all) smoke detectors use around 0.7uCi of Americium-241, but as a flaw in it's production method, trace amounts of plutonium are in smoke detectors. To make Americium-241, Uranium-238 is first turned into plutonium-241 through this nuclear reaction:

1. 238/92 U + 1/0 n -> 239/92 U

2. 239/92 u -> 239/93 Np + 0/-1 beta + antinuetrino

3. 239/93 Np -> 239/94 Pu + 0/-1 beta + antinuetrino

4. 239/94 Pu + 1/0 N -> 240/94 Pu

5. 240/94 Pu + 1/0 n -> 241/94 Pu

(Neutron capture of U-238 into U-239, which beta decays into Np-239, which beta decays again into Pu-239, which captures a neutron to become Pu-240, and then another neutron to become Pu-241)

This reaction typically occurs in nuclear recators, by submerging a high purity U-238 target into the core and leaving it for a specific time proportional to the sample location's neutron flux, target shape, and size. The time is longer than the time you would submerge it in to make weapons grade plutonium.

This target now contains amounts of plutonium 241, and the next step is to extract the plutonium 241 from the target.

The dissolved target solution is mixed with an organic solvnt, diluted in kerosene. The organic solvent disolves plutonium and uranium, bringing them in solution. The solution is then filtered to remove insoluble Actinides. Then the plutonium is stripped out of the organic solvent, and converted into a plutonium dioxide powder or metal that has a high Pu-241 content.

The Plutonium is then aged for years or months to allow the Am-241 to accumulate, and after "aging" the plutonium is then dissolved again and the solution is passed through a ion exchange membrane. Because plutonium and americium have mostly different oxidation states the americium is able to pass through the ion exchange membrane but the plutonium stays, leaving pure americium solution,

However, no chemical seperation is 100% perfect and the ion exchange membrane/resin is no exception, here is how it fails to take all plutonium from the americium.

The ion exchange membrane is supposed to bind to the plutonium while letting the +3 oxidation state Americium pass. However plutonium is like a chameleon existing at many oxidation states in solution, (Pu^(+3), Pu^(+4), Pu^(+5) and Pu^(+6)) whereas americium will primarily exist as Am^(+3) in solution. While the ion exchange membrane is able to keep most plutonium, it fails to effectively keep Pu^(+3), which will always be present in some quantities inside the solution. So therefore, some pultonium will be in the purified americium solution.

So now that we have confirmed that plutonium is (in theory) to be found in americium-241 smoke detectors, the next step is to calculate just how much plutonium can be found.

Industrial separation yields are measured by a Decontamination Factor (DF). For a standard production-grade single anion exchange pass in 8 M HNO₃, the DF for removing plutonium from americium sits conservatively at: DF = 10⁴ (an efficiency of 99.99%)

Finally we need to calculate how much plutonium actually contaminates the final smoke detector sample based on these production paraneters.

A 0.7 µCi smoke detector contains exactly 0.204 µg of pure Am-241. In a typical aged batch of plutonium target material, the americium only makes up a small fraction of the mass befre separation—roughly 1% of the total actinide mix (99% Plutonium, 1% Americium).

Applying the indutrial Decontamination Factor (DF = 10⁴) to the initial mass ratio determines the final mass ratio in the purified product:

(Pu/Am)_final = (Pu/Am)_feed / DF = 99 / 10⁴ = 0.0099

Now, multiply this final ratio by the absolute mass of the Americium-241 found in the smoke detector to solve for the final trace mass of plutonium:

amount of Pu = amount of Am × (Pu/Am)_final

amount of Pu = (2.04 × 10⁻⁷ grams) × 0.0099 ≈ 2.02 × 10⁻⁹ grams

Therefore each smoke detector contains 2.02 × 10⁻⁹ grams of plutonium (2.02 Nanograms) which is equivalent to 5.09x10^(12) atoms per smoke detector. Meaning in every smoke detector, 4.64 atoms of plutonium decay every second (4.64 Bq) This is a little over the amount of atoms of plutonium found per gram of trinitite, and the human body contains around 10^(5) atoms of plutonium.

For me, it is an americium button that is about 20kCPM on my Radiacode 102, what's yours?