Chernobyl reactor core

Chernobyl's nuclear disaster took place on April 26, 1986 — almost 25 years ago — so you might be interested in this photo. I took it on April 17, 2006, at the Chernobyl Visitor's Center, which is located a few hundred yards from the nuclear power plant. I visited Chernobyl as a side trip to the Eurocon science fiction convention, which was held in Kiev, Ukraine, in 2006.

The Visitor Center had this cut-away diorama of the reactor hall to help explain the state of the nuclear power plant. The dark cylinder is the concrete shield around the reactor core. Chernobyl did not have a thick steel reactor vessel inside the shield around the core itself that Fukushima and Three Mile Island had to keep the fuel inside in the event of a problem.

The disk-shaped thing on top with a fuzz of rods is the lid of the reactor shield. It was blown open when the reactor exploded due to sudden buildup of steam pressure, and it now rests askew over the reactor core. Notice the little worker figurines standing on it, which will give you an idea of the size.

Now notice the little worker inside the reactor core. Especially, notice that the reactor core is empty. The uranium and plutonium fuel — 180 tonnes of it — melted and mixed with sand, concrete, zirconium, and other materials. The lava flowed out through the bottom, which had been broken and blown 4 meters down by the blast. That orange stuff next to the core is the lava that flowed through hallways and elevator shafts and into rooms in the basements. A Complex Expedition Team spent years carefully looking for the fuel lava, but 40% of the building has not yet been examined due to high radioactivity and excessive damage. This lack of information about exactly what's down there is one of the most serious present-day risks.

The pink flags mark significant details. Notice the rubble in the reactor hall and the obvious damage. It's all highly radioactive. The "Sarcophagus" — also called the Shelter — was built around the nuclear power plant. The shelter is a massive concrete and steel structure designed to keep the building from falling down and to keep rain and snow from getting into the reactor hall and basements. It's not a tight building; the fuel is still reacting and gives off heat that needs to be vented. Workers also need to enter to inspect the remains of the plant regularly.

Right now, work is underway to build an even bigger Shelter around Chernobyl, because the Sarcophagus isn't entirely sturdy, and the lava is turning into dust and needs better controls, but an international conference to fund the new radiation shield and other safety measures fell short of its fund-raising goal this week. Here's some news stories:
http://www.bbc.co.uk/news/world-europe-13124777
http://uk.news.yahoo.com/22/20110419/twl-uk-ukraine-chernobyl-plans-factbox-7f5ebb3.html

You can learn more about plant and its history at the Chernobyl website, which displays real-time radiation levels.
http://new.chnpp.gov.ua/eng/

What did I learn on my trip? Despite ongoing and responsible efforts by the Ukranian government, the power plant is still a disaster. Chernobyl is not a wasteland — in fact, the Exclusion Zone around the plant is rather lush, which is a problem in itself. But the best that can be done is to keep the situation under control. It cannot be made safe, and Chernobyl requires constant monitoring and maintenance now and for hundreds of years to come.

— Sue Burke