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- Hacker News
- This "dropping" activity is not defined well in the context. Was it e.g. a controlled but uncommanded insertion? Or did something or some three things slip, snap, or something else? Can the rods be retrieved using BAU procedures, or is reactor in an annoying state now?
The details divulged seems to have been driven by event reporting regulations, not any specific news gathering or investigation, right?
by verytrivial - I liked it better in the olden days when the paper would print the location of the story at the beginning of the first paragraph.by paulnpace
- What's probably more interesting than the incident itself is that it elicited well over a hundred comments on this site. Explosions happen at natural gas plants semi-frequently, few make the news, and fewer still are likely to get much attention here.by beloch
- A challenge with news like this is there isn't an easy risk reference to put it into perspective. People only think of Chernobyl, Fukushima, 3-mile island, etc etc. We don't have something personal to relate it to to help us determine 'NBD, why is this a story?' or 'Wow! That was close!'. In everyday life I generally use driving to help me determine how risky something is. Driving is something most people do somewhat regularly and that we recognize as risky so we put controls on like training, regulations, special services, etc etc. Anything more risky than driving makes me really take notice. Anything less and I don't shrug it off, but I also don't get too worried.
I appreciate the factual nature of this story but I think an important aspect of journalism is giving people relatable references that allow them to better understand the information presented. It would be helpful if a story like this gave that context because without it it is hard to understand if this is 'Wow! What a close one!' or 'I guess this is a little interesting?'.
by jmward01 - I actually thought they were talking about the island in the Caribbean since Florida is not mentioned in the article. Anyway, in case you did not know, the reactor in question is in Florida: https://en.wikipedia.org/wiki/St._Lucie_Nuclear_Power_Plant
- https://www.nuclear-power.com/nuclear-power/reactor-physics/...
Can someone check my understanding: Control rods are suspended above the reactor as a sort of a "deadman's switch" - if a loss of power occurs, they will drop into the reactor core to limit reactivity. As a result, sometimes control rods will drop into the reactor accidentally. In these cases, the automatic system may withdraw other rods in order to maintain power output. However, this may overshoot the target power output or create a localized, dangerous "hot spot" elsewhere in the reactor core. In order to avoid this, in this case, the operators chose to insert other control rods instead of trying to stabilize the reactor under load.
by fwipsy - This happened in 2024 too.
This link (second one down, first event is missing control rods in Texas...) has almost the exact same wording as the article.
https://www.nrc.gov/reading-rm/doc-collections/event-status/...
I found the root cause of the older issue on LinkedIn of all places.
https://www.linkedin.com/posts/robert-meyer-8672ab4a_st-luci...
Root cause of 2024 was apparently a procedural issue combined with electrical failure of the control rod grippers.
by aeonik - Dropped rods are an incident but one that occurs because of pressurized water reactors being very default safe. Controls rods are one way the criticality of a reactor is controlled and US reactors (in general) will go sub critical if even one rod is fully inserted into the core. You will likely have heard of a reactor scram (which goes back to the safety control rod ax man) where in an emergency, all the rods are dropped back into the core, greatly reducing its criticality. In some cases, an interruption of electrical power will cause a rod (or three) to drop accidentally. This is a "dropped rod" incident and will force a reactor shut down because it is now sub critical.
Lots of knock on effects -- sub critical, let heat in the primary loop, less steam and electricity generated in the secondary loop, etc -- but generally a non event that you practice for.
There's no reason this would lead to a radiological event or more significant casualty.
by CoryOndrejka