Here is a concise summary of the provided text about the Chernobyl disaster:
**Background**
* Chernobyl's Reactor 4 (RB MK1000 type, 1960s design) was flawed, with a positive void coefficient, leading to accelerated reactions with increased heat.
* The reactor lacked a robust containment structure, unlike Western designs.
**Disaster**
* In 1986, during a safety test, the reactor exploded due to a design quirk and human error, releasing massive radiation into the atmosphere.
* The blast contaminated large areas of Belarus and Ukraine, causing widespread fear across Europe.
**Aftermath & Cleanup**
* A temporary "sarcophagus" was built in 200 days to contain the radiation.
* Over 500,000 "liquidators" worked to clean up the site, often without proper protection.
* In 2016, a new, permanent containment arch was constructed and installed, ensuring safer containment.
**Legacy**
* The disaster highlighted the Soviet system's flaws and contributed to its downfall.
* Russia still operates 10 retrofitted RB MK reactors, with plans to run the last one until 2034.
* The cleanup process will continue for decades, with the abandoned city of Pripyat serving as a haunting reminder of the tragedy.
Here are the key facts extracted from the text, without opinions, with each fact numbered and in short sentences:
**Reactors and Design**
1. The Chernobyl power plant had four nuclear reactors.
2. The reactors were brought online over six years.
3. Unit 4 had been operational for three years at the time of the disaster in 1986.
4. The reactor design was the RB MK1000 type, from the 1960s.
5. The uranium fuel was only slightly enriched, resulting in a larger reactor core.
6. The reactor had a positive void coefficient, meaning increased heat accelerated the reaction.
**Containment and Safety**
7. Western reactors are designed to be stable, with heat reducing the nuclear reaction.
8. Chernobyl's reactor had only one containment layer, unlike Fukushima's three.
9. The reactor lacked a pressure vessel, allowing for refueling at full power.
10. The control room was located outside the reactor building, in the turbine hall.
**Disaster and Aftermath**
11. The disaster occurred during a safety test on the reactor.
12. The chief engineer bypassed multiple automated safety systems.
13. Vast amounts of radiation were released directly into the atmosphere.
14. Radioactive fuel debris was scattered around the site.
15. Large areas of Belarus and Ukraine were made uninhabitable.
16. Radiation was detected in low amounts across Europe.
**Cleanup and New Containment**
17. An emergency concrete cover (the "sarcophagus") was built in 200 days.
18. The sarcophagus was not a final solution and began rusting and cracking over time.
19. A new permanent containment arch was constructed and rolled into place in November 2016.
20. The new arch is the largest movable land structure ever made.
**Legacy and Other Reactors**
21. The cleanup activities involved up to 500,000 people ("liquidators").
22. The other Chernobyl reactors continued to run after the disaster.
23. Unit 2 burned in 1991 and was abandoned.
24. The last director was switched off in 2000.
25. Russia still operates 10 RB MK reactors, with plans to run the last one until 2034.
26. These units were retrofitted with safety modifications.
**Pripyat and Miscellaneous**
27. Pripyat was a model town of 50,000, evacuated in one afternoon after the explosion.
28. The Pripyat amusement park was set to open on May Day, but was hastily opened early instead.