The Wikipedia snippet below is not backed by a reliable source. Can you find one?
Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!
In page Protactinium:
"Protactinium-231 arises from the decay of uranium-235 formed in nuclear reactors, and by the reaction 232Th + n → 231Th + 2n and subsequent beta decay. It was once thought to be able to support a nuclear chain reaction, which could in principle be used to build nuclear weapons: the physicist Walter Seifritz [de] once estimated the associated critical mass as 750±180 kg.[2] However, the possibility of criticality of 231Pa has been ruled out since then.[3]
You can customize Citation Hunt by importing a list of articles into it. This gives you a link that you can share with others so they browse Citation Hunt limited to the articles you provided.
Where would you like to import articles from?
Please enter Wikipedia article titles to import, one per line, in the area below:
PetScan is a tool for querying Wikipedia and defining lists of articles. PetScan assigns IDs to queries so their results can be imported into other tools.
Please create your query in PetScan and paste its ID below:
Tip: Citation Hunt only contains articles inside the All_articles_with_unsourced_statements category. For better results, you can use PetScan to only retrieve articles inside that category.
Please wait, your custom Citation Hunt is being computed. This may take a few minutes…
You can press Back or close this dialog to cancel.
Your custom Citation Hunt has been created!
You can copy and share the link above to allow other people to use it, or start browsing it now!
Sorry, your custom Citation Hunt failed to be created or came up empty!
Please try again and keep the following tips in mind: