A Few Nuclear Nuts and Bolts

Rusted bolt.Photo by <a href="http://commons.wikimedia.org/wiki/File:Rust_Bolt.JPG">Thester11, via Wikimedia Commons</a>.

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


I wrote last week about the issue of saltwater corrosion, referring to the less-than-stainless nature of stainless steel. I heard back from a knowledgeable reader who reminded me:

Stainless steel has two nominal positions on the electrochemical series. In the absence of [oxygen] the alloy becomes highly active and thus subject to very high rates of corrosion, including fatigue corrosion. Heated water, particularly boiling water, [off]gasses latent [oxygen] almost immediately, thus stainless steels in such an environment rapidly corrode due to both becoming active and being at an elevated temperature.

Sounds like a nasty brew in a boiling-water reactor. More alarmingly, this reader told me that a hot reactor doused with seawater would likely drive flanged bolts—particularly stainless-steel bolts—to failure in as little as months, and that steam plants are pegged together with thousands of flanged volts.

Meanwhile, authorities in Japan are finally voicing the reality that the situation at Fukushima is going to need babysitting for years.

 

Example of a spent fuel pool. Credit: DOE via Wikimedia Commons.Example of a spent fuel pool. Credit: DOE via Wikimedia Commons.

 

In this week’s issue of Science, Eli Kintisch takes a chilling look at the realities of reactor #4 at the Fukushima plant—especially in light of the fact that the reactor was offline at the time of the quake. Its spent fuel rods were still cooking though in their spent-fuel pool.

Concerns among scientists amp up because there are more than 350 reactors worldwide with spent-fuel pools too, and no one knows why #4 has behaved as badly as it has:

The pool held the entire complement of fuel rods from the reactor’s core, which had been emptied 3 months before the 11 March earthquake and tsunami struck. And yet on 15 March the building exploded, apparently fueled by hydrogen, leaving nuclear engineers to speculate about the source. Adding to the confusion are reports of fires in the pool, a worst-case scenario that had never before occurred in a working nuclear plant.

The problem at #4 might be related to the zirconium alloy tubes holding the spent fuel rods.

Lab experiments have shown that zirconium can burn either with steam or with oxygen. Both reactions progress rapidly at roughly 800°C [1,472°F]; the former, crucially, releases hydrogen. The hydrogen explosion at reactor #4 points to the steam reaction, which releases less energy and therefore melts the fuel more slowly. But knowing which reaction dominated could help scientists quantify how much radioactivity was released from pool #4. A 2006 study by the U.S. National Research Council said that a heat up after a loss-of-water event could melt the spent fuel, allowing the escape of volatile radionuclides, including “a substantial fraction of the cesium,” into the air.

 An alga from the genus Closterium. Credit: 	  ja:User:NEON / User:NEON_ja, via Wikimedia Commons.An alga from the genus Closterium. Credit: ja:User:NEON / User:NEON_ja, via Wikimedia Commons.

 

Richard A. Lovett at Nature reports on a presentation yesterday at a meeting of the American Chemical Society on the power of a humble alga, Closterium moniliferum, to remove the element strontium from water and then deposit it in crystals inside its own cells.

Minna Krejci, a materials scientist at Northwestern University, believes Closterium might have a talent for cleaning up the radioactive isotope strontium-90—a dangerously carcinogenic isotope that infiltrates milk, bones, bone marrow, blood, and other tissues.

The algae don’t actually target strontium. Instead, they incidentally collect strontium as they go about the business of gathering barium. But that could work in our favor cleaning up radioactive water.

Krejci’s research has found that it is possible to enhance the uptake of strontium by tailoring the amount of barium in the algae’s environment. This, she says, means that it might prove possible to seed nuclear waste, or a spill of radioactive material, with barium to encourage the algae to grab the strontium—easy to do, she says, because “it would only be a small amount” of barium. It might also be possible to improve the process by tinkering with sulphate levels in the environment, thereby changing the amount of sulphate in the vacuoles. “Once we learn about how the cells respond to conditions, we can think of more elegant ways to manipulate them,” says Krejci. Once isolated by the bacteria, the strontium could be sequestered in high-level nuclear waste repositories, while the rest of the waste could go to a less expensive lower-level repository, saving space and money. Currently, Krejci says, there are hundreds of millions of litres of stored nuclear waste in the United States alone, much of which contains strontium. “So we know it’s a big problem,” she says.

AN IMPORTANT UPDATE

We’re falling behind our online fundraising goals and we can’t sustain coming up short on donations month after month. Perhaps you’ve heard? It is impossibly hard in the news business right now, with layoffs intensifying and fancy new startups and funding going kaput.

The crisis facing journalism and democracy isn’t going away anytime soon. And neither is Mother Jones, our readers, or our unique way of doing in-depth reporting that exists to bring about change.

Which is exactly why, despite the challenges we face, we just took a big gulp and joined forces with the Center for Investigative Reporting, a team of ace journalists who create the amazing podcast and public radio show Reveal.

If you can part with even just a few bucks, please help us pick up the pace of donations. We simply can’t afford to keep falling behind on our fundraising targets month after month.

Editor-in-Chief Clara Jeffery said it well to our team recently, and that team 100 percent includes readers like you who make it all possible: “This is a year to prove that we can pull off this merger, grow our audiences and impact, attract more funding and keep growing. More broadly, it’s a year when the very future of both journalism and democracy is on the line. We have to go for every important story, every reader/listener/viewer, and leave it all on the field. I’m very proud of all the hard work that’s gotten us to this moment, and confident that we can meet it.”

Let’s do this. If you can right now, please support Mother Jones and investigative journalism with an urgently needed donation today.

payment methods

AN IMPORTANT UPDATE

We’re falling behind our online fundraising goals and we can’t sustain coming up short on donations month after month. Perhaps you’ve heard? It is impossibly hard in the news business right now, with layoffs intensifying and fancy new startups and funding going kaput.

The crisis facing journalism and democracy isn’t going away anytime soon. And neither is Mother Jones, our readers, or our unique way of doing in-depth reporting that exists to bring about change.

Which is exactly why, despite the challenges we face, we just took a big gulp and joined forces with the Center for Investigative Reporting, a team of ace journalists who create the amazing podcast and public radio show Reveal.

If you can part with even just a few bucks, please help us pick up the pace of donations. We simply can’t afford to keep falling behind on our fundraising targets month after month.

Editor-in-Chief Clara Jeffery said it well to our team recently, and that team 100 percent includes readers like you who make it all possible: “This is a year to prove that we can pull off this merger, grow our audiences and impact, attract more funding and keep growing. More broadly, it’s a year when the very future of both journalism and democracy is on the line. We have to go for every important story, every reader/listener/viewer, and leave it all on the field. I’m very proud of all the hard work that’s gotten us to this moment, and confident that we can meet it.”

Let’s do this. If you can right now, please support Mother Jones and investigative journalism with an urgently needed donation today.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate