海 嘯暴露了一些核電站在設計上的致命缺陷：一個底面積只有一張餐桌大小的電氣開關設備的擺放位置令人質疑。在設計較新的核電站內﹐這一設備與反應堆一起放置 在一座堅固的建築物內。在設計較舊的核電站內﹐這一設備被安放在缺乏保護的附屬建築內。這個附屬建築是最初設計遺留下來的。海嘯襲來之際﹐這些電氣開關被 沖毀﹐令正在運轉的發電機停止發電。
這篇報道是基於對東京電力公司12位現任和前任高級工程師的採訪寫就而成的﹐有好幾位曾在上世紀70 年代這一對後世命運有決定性影響的設計最終拍板時深入參與其中。一些工程師說﹐幾十年來東京電力公司曾有過機會改造升級最老的核反應堆。這些人認為﹐自 滿、削減成本的壓力以及寬鬆的監管是造成東京電力公司始終沒有這麼做的原因。
日 本並非惟一在與核反應堆老化作鬥爭的國家。美國有幾十座反應堆的運營時間超過30年﹐其中23座與福島核電站老舊的反應堆一樣使用通用電氣公司 （General Electric Co.）的設計。還有幾座在未來幾年面臨重新獲得牌照的惡戰。其它國家裡﹐德國和瑞士已經決定逐步淘汰老化的核電站﹐並最終棄用核電。
Norihiko Shirouzu / Chester Dawson
Design Flaw Fueled Nuclear DisasterSome senior engineers at Tokyo Electric Power Co. knew for years that five of its nuclear reactors in Fukushima prefecture had a potentially dangerous design flaw, but the company didn't fully upgrade them, dooming them to failure when the earthquake hit, a Wall Street Journal examination of the disaster shows.
The company used two different designs for safeguarding its 10 reactors in Fukushima. When the devastating quake struck on March 11, the five reactors with the newer design withstood the resulting 45-foot tsunami without their vital cooling systems failing. Those reactors shut down safely.
But the cooling systems failed at four reactors with the older design. Backup diesel generators and electrical-switching equipment were swamped by seawater. As a result, fuel melted down at three reactors and there were explosions at several reactor buildings, culminating in the largest release of radiation since Chernobyl.
The tsunami exposed an Achilles heel in the design of some of the plants: the questionable placement of a single kitchen-table-size electric-switching station. At newer plants, the station was in a robust building that also housed the reactor. In others, it stood in a poorly protected outbuilding─a relic of the original design. When the tsunami hit, those switches were knocked out, rendering operating generators useless.
This article is based on interviews with a dozen current and former senior Tokyo Electric Power engineers, including several who were intimately involved when the fateful design decisions were made in the 1970s. Some of them say the company, known as Tepco, had opportunities over the decades to retrofit the oldest reactors. They blame a combination of complacency, cost-cutting pressures and lax regulation for the failure to do so.
'There's no doubt Tepco should have applied new designs' throughout Fukushima, says Masatoshi Toyota, 88 years old, once a top Tepco executive who helped oversee the building of the reactors. He says he blames himself for not noticing the design problems and correcting some of them later.
A spokesman for Tepco declined to comment for this story, citing the Japanese government's ongoing investigation into the cause of the accident.
Japan isn't the only nation grappling with aging nuclear reactors. The U.S. has dozens of reactors that have operated for more than 30 years, and 23 with the same General Electric Co. design as the older Fukushima reactors. Several face fights over relicensing in the next few years. Elsewhere, Germany and Switzerland have decided to phase out their aging plants and drop nuclear power altogether.
All the Fukushima plants, including the newer ones, were based on GE designs. GE maintained lucrative contracts to service GE reactors in Japan and was engaged with partner Hitachi Ltd. in a global campaign to extend the lives of its aging plants.
GE said any flaws at the Fukushima reactors weren't its fault because Tepco was in charge of design changes. 'The location of emergency diesel generators at the Fukushima Daiichi plant were reviewed and approved by Tepco and regulatory authorities,' said GE spokeswoman Catherine Stengel.