On a December afternoon in Chicago during the middle of World War II,scientists cracked open the nucleus at the center of the uranium atom and turned nuclear mass into energy over and over again.

第二次世界大戰期間,時值芝加哥12月份的一個下午,科學家們敲開了鈾原子中心的原子核,一遍又遍地重復將質量轉化成能量這一過程。

They did this by creating for the first time a chain reaction inside a new engineering marvel:the nuclear reactor.

他們創造了在世界上尚屬首次的連鎖反應工程新奇跡:核反應爐

Since then, the ability to mine great amounts of energy from uranium nuclei has led some to bill nuclear power as a plentiful Utopian source of electricity.

自此,人類從鈾原子核中提取巨量能源,使一些人將核能視為一種非常充足的烏托邦式電力來源。

A modern nuclear reactor generates enough electricity from one kilogram of fuel to power an average American household for nearly 34 years.

一個現代的核反應堆裝填一公斤的核燃料所發的電力足夠一個普通美國家庭使用大約34年。

But rather than dominate the global electricity market,nuclear power has declined from an all-time high of 18% in 1996 to 11% today.

但核能并沒有占據全球電力市場的主導地位反而從1996年的18%的歷史高點下降到現在的11%

And it's expected to drop further in the coming decades.

而且預計在未來的幾十年里,還將進一步下滑

What happened to the great promise of this technology?

核能發電這項技術的美好前景到底遭遇了什么?

It turns out nuclear power faces many hurdles,including high construction costs and public opposition.

事實證明,核能發電面臨著許多障礙,包括高昂的建設成本和公眾的反對聲浪。

And behind these problems lie a series of unique engineering challenges.

這些障礙背后還有一系列罕見的工程挑戰。

Nuclear power relies on the fission of uranium nuclei and a controlled chain reaction that reproduces this splitting in many more nuclei.

核子能量的釋放依賴于鈾原子核的裂變和受控的連鎖反應,連鎖反應在旁邊的眾多鈾原子核中復制了這種裂變

The atomic nucleus is densely packed with protons and neutrons bound by a powerful nuclear force.

密密麻麻包圍著原子核的質子和中子,受到強大的原子核力束縛

Most uranium atoms have a total of 238 protons and neutrons,but roughly one in every 140 lacks three neutrons,and this lighter isotope is less tightly bound.

多數鈾原子質子和中子的個數加起是283個,但是大約每140個鈾原子就有一個鈾原子缺少3個中子,這種輕的鈾同位素結合地還不太穩定。

Compared to its more abundant cousin,a strike by a neutron easily splits the U-235 nuclei into lighter, radioactive elements called fission products,in addition to two to three neutrons,gamma rays,and a few neutrinos.

與它穩定的親戚相比,一個中子的撞擊輕易地將鈾-235分裂成更輕的放射性元素,即裂變產物,裂變產物還包含二到三個中子、伽馬射線和一些中微子。