Sorry, but your link is wrong. Chernobyl can not be described as a PWR, pressurized water reactor. At best it is closer to a Boiling Water Reactor, BWR.
PWR, BWR, RBMK, Those letters all mean something.
The Chernobyl accident in 1986 was the result of a flawed reactor design that was operated with inadequately trained personnel. Two Chernobyl plant workers died on the night of the accident, and a further 28 people died within a few weeks as a result of acute radiation poisoning.
world-nuclear.org
The RBMK-1000 is a Soviet-designed and built graphite moderated pressure tube type reactor, using slightly enriched (2% U-235) uranium dioxide fuel. It is a boiling light water reactor, with two loops feeding steam directly to the turbines, without an intervening heat exchanger