It is significant that we did not learn the degree of melting until several years later, when the reactor vessel’s radioactivity had decayed sufficiently to open it.

我们是在事故发生数年之后才了解到当时核燃料融化的情况，因为那个时候反应炉的辐射才衰变至足以安全开炉的程度，这一点很重要。

youdao

Ok, select one of the box and then go to the Reactor panel click on Open Property Editor.

好，选择其中一个方体和到反应堆面板点击打开特征编辑器。

youdao

In addition, many of our laboratories studying nuclear fusion are closing, while France plans to open a nuclear-fusion reactor in 2019.

WSJ: The Weekend Interview with Michio Kaku: Captain Michio and the World of Tomorrow

That thinking changed on March 28, 1979, when a small valve stuck open, cooling water escaped and the reactor core of TMI's Unit 2 began to melt.

CNN: Three Mile Island, 20 years later

By the way, some argue that Petrobras should push the government to open the area of the port where the reactor is placed to the general public.

FORBES: Infrastructure Problems in Brazil: Equipment Imported by Petrobras From Italy Has Been Stuck in a Port For Over a Month