# Chernobyl's #4 reactor core **URL:** \ **Category:** Factual Questions\ **Created:** [October 31, 2004, 7:34pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180 "2004-10-31T19:34:48Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![mitchythekid](https://avatars.discourse-cdn.com/v4/letter/m/c67d28/32.png) [@mitchythekid](https://boards.straightdope.com/u/mitchythekid)\ **Post date:** [October 31, 2004, 7:34pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/1 "2004-10-31T19:34:48Z")
🆒 Is the reactor core/the fuel rods at Chernobyl still red hot,still in a molten state,or has it cooled to a point were the material is just a blob of raidoactie waste? ---
**Author:** ![1010011010](https://avatars.discourse-cdn.com/v4/letter/1/ea666f/32.png) [@1010011010](https://boards.straightdope.com/u/1010011010)\ **Post date:** [October 31, 2004, 8:29pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/2 "2004-10-31T20:29:55Z")
It solidified. Here’s [a picture of the “Elephant’s Foot”](http://www.spaceman.ca/gallery/chernobyl/sark3b) formed from Rx4. It’s known as “corium”… though I don’t know if that’s just scientists being funny, or if there’s anything genuinely unique about it from a geological perspective. While nuclear materials can maintain their temperature above ambient (very precise (and expensive) calorimetric thermal standards are often made this way), I doubt the Chernobyl site would still be terribly warm. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [October 31, 2004, 9:47pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/3 "2004-10-31T21:47:46Z")
I think the OP is making the mistake of thinking the Chernobyl explosion was actually a nuclear explosion, or meltdown. It was neither - it was just a steam explosion caused by water coming into contact with hot ruptured fuel sections, which threw large amounts of radioactive material into the surrounding area and into the athmosphere. If it had been a true nuclear event, it’d have been _far_ worse. ---
**Author:** ![Revtim](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/revtim/32/1042_2.png) [@Revtim](https://boards.straightdope.com/u/Revtim)\ **Post date:** [October 31, 2004, 9:54pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/4 "2004-10-31T21:54:16Z")
> [@1010011010](#): > > It solidified. Here’s [a picture of the “Elephant’s Foot”](http://www.spaceman.ca/gallery/chernobyl/sark3b) formed from Rx4. That’s a pretty cool photo gallery. There’s another good pic of the foot in that gallery here: [http://www.spaceman.ca/gallery/chernobyl/fruin11m](http://www.spaceman.ca/gallery/chernobyl/fruin11m) It reminds me of “pillow lava”, lava that erupts underwater. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [October 31, 2004, 10:39pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/5 "2004-10-31T22:39:53Z")
> [@1010011010](#): > > It solidified. Here’s [a picture of the “Elephant’s Foot”](http://www.spaceman.ca/gallery/chernobyl/sark3b) formed from Rx4. Scary stuff, 666. Bet that gives you that warm fuzzy feeling every time you go to work, doesn’t it… Am I correct in assuming from your new ocation that you are out of Prototype already? ---
**Author:** ![Capt\_B.Phart](https://avatars.discourse-cdn.com/v4/letter/c/9fc29f/32.png) [@Capt\_B.Phart](https://boards.straightdope.com/u/Capt_B.Phart)\ **Post date:** [November 1, 2004, 12:08pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/6 "2004-11-01T12:08:04Z")
> [@GorillaMan](#): > > I think the OP is making the mistake of thinking the Chernobyl explosion was actually a nuclear explosion, or meltdown. It was neither - it was just a steam explosion caused by water coming into contact with hot ruptured fuel sections, which threw large amounts of radioactive material into the surrounding area and into the athmosphere. If it had been a true nuclear event, it’d have been _far_ worse. I’ve always assumed that the heat that caused the “lava” to form the elephant’s foot was nuclear in origin, OK, not the full-on “China syndrome” but technically a “nuclear meltdown” I know the Windscale incident was a chemical fire - the graphite used as a moderator caught fire - but that’s not the case with Chernobyl. Can anyone enlighten me as to what happened at Chernobyl? specifically, how did the “lava” get out of the containment vessel - did it melt its way out, did the vessel rupture at the bottom in the original explosion or did the lava form from the material thrown out of the top? ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [November 1, 2004, 12:12pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/7 "2004-11-01T12:12:15Z")
The ‘elephant’s foot’ 'was simply molten fuel and debris that leaked out of the reactor before solidifying - yes, it was _very_ hot, but it wasn’t the result of an out-of-control nuclear reaction, but merely(!) the loss of cooling systems and controls that allow a controlled reaction. ---
**Author:** ![GorillaMan](https://avatars.discourse-cdn.com/v4/letter/g/50afbb/32.png) [@GorillaMan](https://boards.straightdope.com/u/GorillaMan)\ **Post date:** [November 1, 2004, 12:15pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/8 "2004-11-01T12:15:45Z")
Oh, and yes, it escaped because of damage from the explosion. ---
**Author:** ![Capt\_B.Phart](https://avatars.discourse-cdn.com/v4/letter/c/9fc29f/32.png) [@Capt\_B.Phart](https://boards.straightdope.com/u/Capt_B.Phart)\ **Post date:** [November 1, 2004, 2:23pm UTC](https://boards.straightdope.com/t/chernobyls-4-reactor-core/272180/9 "2004-11-01T14:23:16Z")
> [@GorillaMan](#): > > yes, it was _very_ hot No shit! > [@](#): > > From analysis of the lava’s composition, Pazukhin estimated that the maximum temperature of the explosion was about 2255 degrees Celsius and that the lavas must have been held at a temperature greater than 1660 degrees for at least 4 days. He believes that when the reactor exploded, chunks of concrete from the walls collapsed into the reactor chamber. The fuel rods heated to the point that their zirconium cladding melted, exposing the uranium oxide fuel. About 4 hours later, melting concrete, zirconium, and uranium oxide began to mix with about 145 tons of the mineral serpentine which was packed around the reactor as heat insulation. Within half an hour the serpentine heated to more than 500 degrees Celsius and began to decompose, releasing 19 tons of superheated water as vapor. The melted materials cooked for another 60 hours, forming a lava that flowed into several damaged rooms beneath the reactor chamber. [From here](http://library.thinkquest.org/3426/data/chernobyl-today/missing.fuel.html) written before the discovery of the “elephants foot” by the “stalkers” (who were named, I’m guessing after the Tarkovsky film or “roadside picnic” on which it was based)