I've spent a lot of time defending the nuclear industry, now I'm going to tell you about my odd passion within the industry, what happens when things go wrong.
A subcritical configuration refers to nuclear material that is not contributing to a continuing reaction. A critical configuration usually produces as many or more neutrons per "generation" as the last generation had. Criticality accidents are accidents where nuclear material was supposed to be subcritical but error led to nuclear material becoming critical. When nuclear becomes critical, or even supercritical, it becomes dangerous for humans to be around because more and more radiation is being created and human exposure could become lethal very quickly.
Critical or supercritical configurations aren't necessarily bad. Nuclear reactors need to become critical in order to continue producing energy. However, you don't really want to be in the same room when it happens.
Criticality accidents are my personal passion within the nuclear industry because they highlight how important it is to do things by the book and to pay attention. I also sort of enjoy seeing how nuclear research safety rules have changed in order to prevent accidents. Most importantly, it shows that the people that suffer most from radiation are the people working with it and it acts as a reminder to always think through the risk.
For my next couple of posts I'll be talking about criticality accidents. What went wrong? What went right? What could have been done to prevent it?
I learned in a criticality class about something called a re-entrant surface. Basically, when fissile material is in solution, the geometry of that solution is subject to change when subjected to some force or vibration. If the change in geometry of the liquid is such that escaping neutrons, which would normally escape the fissile solution and continue as a leaked particle, may re-enter the solution to induce more fissions - which can result in an effective multiplication factor greater than 1.
ReplyDeleteThe last sentence isn't a sentence and will remain as such.
DeleteI find nuclear accidents really interesting. It is good to know what went wrong in an accident or what was the cause that lead to it. This is because it helps other people in the industry take preventative measures. Therefore, lower the risk of an accident.
ReplyDeleteCan you add into the next few posts what changes were made, which laws were created, or social impacts the accidents had? Any idea if you'll be focusing on more recent or old (like the first few) accidents?
ReplyDeleteI'll begin with the older accidents since they had a bigger impact on how nuclear research was conducted. Right now I'm trying to narrow down which accidents had the biggest effect or the most drastic consequences. Of course, I'm also going to cover my favorite accidents, which mostly consist of "when you do stupid things, bad things happen to you (aka scientists are not gods)."
DeleteLooking forward to it! Especially any pertaining to your last point. It's rather embarrassing how many nuclear accidents (or almost-accidents) occur purely out of human error like bad assumptions or lax protocols.
DeleteThis was a very interesting blog post! I have an interview with a company that specializes in guaranteeing criticality safety of the nation's stock of uranium and look forward to the opportunities and fun times working as a crit engineer!
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