A team of officials from the U.S. Nuclear Regulatory Commission visit the destroyed Fukushima Daiichi in Japan December. (Photograph courtesy NRC/Flickr)

A team of officials from the U.S. Nuclear Regulatory Commission visit the destroyed Fukushima Daiichi in Japan December. (Photograph courtesy NRC/Flickr)

 

BURN is partnering with National Geographic’s The Great Energy Challenge blog – a three-year initiative designed to help all of us better understand the breadth and depth of our current energy situation. Here is an excerpt from a GEC post by BURN host Alex Chadwick.

Safety Question on Fukushima Anniversary: Should Plants of the Same Design Have Filtered Vents?

When the giant winter storm Nemo hit New England in February, the Pilgrim Nuclear Power Generating Station in Plymouth, Massachusetts, lost outside power for seven days. Diesel backups took over operating the reactors’ cooling system. (Related Quiz: “What Do You Know About Nuclear Power?”)

Pilgrim has the same kind of reactors that failed at Fukushima, Japan, after an earthquake and tsunami two years ago today crippled offsite power and emergency back-ups. The Pilgrim incident came as the U.S. nuclear industry is fighting proposed new safety measures meant for a crisis that might begin exactly this way. (Related: “Rare Video: Japan Tsunami“)

Of the 104 reactors in the U.S., 31 are very like those in Fukushima. Here is a map of those 31 U.S. sites.

After Fukushima, the U.S. Nuclear Regulatory Commission (NRC) studied what happened. Should it require new safety measures here, even though a crisis is very unlikely?

“It’s not zero,” says Charles Casto, director of NRC Region III, which oversees plants in the Midwest. “The probability’s not zero; it’s something.”

Region III has about two dozen reactors. We spoke at Casto’s office. Nuclear regulation, he said, is about possibility more than probability.

“You take your best – based on history…you know, what has history shown you that the probability would be?” Casto said. “But that doesn’t mean zero.”

Gas Build-Up

The Fukushima reactors, and their 31 U.S. cousins, including the Pilgrim Station, are old boiling water reactors with “Mark I” and “Mark II” containment systems, built by General Electric. The safety enclosures for the reactors are too small. If their cores start to melt down, the containments could fail in several ways, including a build-up of hydrogen gas with radioactive particles and explosion, as at Fukushima. (Related: “Japan Reactor Crisis: Satellite Pictures Reveal Damage“) There’s an increasingly politicized dispute between the industry and the NRC over how to make preventing meltdowns safer.

READ || The rest of Alex’s story for National Geographic’s Great Energy Challenge.

LISTEN || BURN’s story on US reactor venting concerns, post-Fukushima.