[originaltext] (5) (6) South Korea has shut down two nuclear reactors after

(5) (6) South Korea has shut down two nuclear reactors after it was revealed that some parts used had not been properly checked. The shutdown means there could be unprecedented power shortages in the next few months. The more than 5,000 parts could be used in other industries but needed international certification for nuclear power plant usage.
    Almost all the parts were used at the Yeonggwang Nuclear Power Plant, in the south-west, where the two reactors were shut down. It’s inevitable that this area will experience unprecedented power shortage during the coming winter with the two reactors shut.
    (7) South Korea’s 23 nuclear reactors, which supply 35% of the country’s electricity, have experienced a series of malfunctions over the past few months.
    While none have posed a public risk, opposition to the government’s bid to vastly expand its nuclear industry has been growing.
5. Which is the main idea of the news?
6. Why did the authorities make such a decision?
7. How many nuclear reactors does South Korea have?