Sunday, March 28, 2010

SVBR in New York Times; Bellona Unimpressed

The SVBR, which I first blogged about last year, is continuing to gain increasing attention in the American media. On March 18th the New York Times published an article about the reactor, titled "Safety Issues Linger as Nuclear Reactors Shrink in Size."

According to the article:
Environmentalists say the technology is outdated and potentially dangerous, and marketing it as green energy is an abuse of nuclear power’s good green name.
. . . .

The kinds of marine reactors the Russians are promoting, though, also happen to create a byproduct — used fuel — that no one knows how to handle. Right now, that spent fuel is being stored at naval yards in the Russian Arctic.

In most nuclear facilities, the used fuel, which is highly radioactive, is removed from the reactor and stored in a pool of water. But in the Soviet submarine model currently advanced by a Moscow company, the spent fuel ends up frozen along with the reactor and stored away. No engineering solution has been devised yet to decontaminate the fuel.

I'm fairly sure that the authors are confused here, and are conflating the problem of spent nuclear fuel with those posed by the lead-bismuth coolant. According to Gidropress, the SVBR is planned to use uranium oxide fuel enriched to 16.5% U-235. There is considerable practical and experimental experience reprocessing oxide fuel, so it's hard to understand why SVBR fuel assemblies would supposedly be impossible to reprocess. Indeed, the Russians specifically tout "Возможность работы в замкнутом ядерном топливном цикле"--the possibility of operating on a closed fuel cycle.

I think that the problem that the authors really mean to be addressing is not that posed by the spent fuel itself, but rather the hazards posed by the lead-bismuth coolant. When irradiated by neutrons, some of the lead coolant is transmuted into Polonium-210. And while lead-bismuth has a substantially lower melting point than lead, it still poses serious challenges if it freezes. This was the Achilles' heel of the reactors used in the Soviet Alfa submarine--when the coolant froze, there was no way to either restart the reactor or "defrost" it to extract the spent fuel, and the coolant itself posed significant radiation hazards. This was due to limitations of the early lead-bismuth reactor designs. The SVBR is specifically designed to avoid this problem--indeed, the reactor is supposed to be shipped from the factory pre-loaded with frozen lead-bismuth coolant. As Gail the Actuary stated on the Oil Drum last year: "The SVBR-100 is cooled by a lead-bismuth eutectic alloy which is loaded into the reactor at the factory. After testing, the heavy metal coolant is allowed to “freeze”, and the modular SVBR-100 reactor is transported to its power plant destination via railroad flat car for installation."

Presuming that the SVBR actually achieves this, Bellona's concerns about the design are moot. Disappointingly, the NYT echoes the Norwegian-Russian antinuclear group in implying that the SVBR is somehow "unsafe." This is in fact the opposite of reality--the SVBR should be considerably safer than existing LWR designs thanks to the high boiling point of the lead-bismuth coolant, low operating pressure, passive heat removal, and other advanced safety features. The coolant freezing issue would never be a hazard to the public in any case--even if it did render a reactor inoperable, it does not follow that it would result in an accident resulting in a major radiation release. Indeed, as the Russians' spokeswoman Anna Kudryavtseva stated, the liquid-metal reactor would be “maximally safe even in not very capable hands.”

On the whole it's good to see the SVBR receiving more attention, but it's disappointing that the article gives such a misleading impression of the technology. Only time will tell if the Russians overcome the engineering challenge to make the lead-bismuth reactor a commercial practicality, but that doesn't excuse this kind of sloppy reporting.

3 comments:

DV8 2XL said...

There are a about sixty small reactor concepts making the rounds these days. The SVBR is going to have to line up with a number of designs that probably have a better chance of type-approval by Western regulators.

The Russians might be able to develop a domestic market for these reactors, but the likelihood of them making headway in other markets is slim.

Which is too bad, because the design has much to commend it.

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pngai said...

The NYT article is assuming that if the coolant freezes, it will be physically impossible to remove the fuel rods because the fuel rods will be encapsulated in solid metal. That seems like a reasonable assumption to me.