NuScale Power Awarded $226 Million To Deploy Small Nuclear Reactor Design

New submitter ghack writes "NuScale power, a small nuclear power company in Corvallis Oregon, has won a Department of Energy grant of up to $226 million dollars to enable deployment of their small modular reactor. The units would be factory built in the United States, and their small size enables a number of potential niche applications. NuScale argues that their design includes a number of unique passive safety features: 'NuScale's 45-megawatt reactor, which can be grouped with others to form a utility-scale plant, would sit in a 5 million-gallon pool of water underground. That means it needs no pumps to inject water to cool it in an emergency - an issue ... highlighted by Japan's crippled Fukushima plant.' This was the second of two DOE small modular reactor grants; the first was awarded to Babcock and Wilcox, a stalwart in the nuclear industry."

Re:What about accidents?

[i kan reed]

Leaks can be detected and contained at relatively low levels and happen with "big nukes" too. And it's nowhere near the environmental risk that meltdowns are.

Re:This gets funding

[weilawei]

The MSRE was a resounding success. We gained practical experience with a new technology: a far safer and more efficient iteration of nuclear power. We made mistakes (metal embrittlement, evolution of uranium and plution)--and we learned from them. They were costly in terms of money, but we walked away with the knowledge to do it better the next time. This is how science and engineering works.

Re:This gets funding

[Ralph Wiggam]

Getting Thorium power off the ground is going to require at least $20B, two orders of magnitude more money than what we're talking about here.

I'm a proponent of Thorium power, but there is an absolutely massive amount of work to be done between now and industrial scale power generation.

Re:This gets funding

[weilawei]

Take your FUD somewhere else.

The metal problem was solved with Hastelloy-N [moltensalt.org] by adding various alloys (primarily 1.1% Nb) and they predicted it to have a sufficient lifetime for an operational reactor. That was in 1977.

A metallographic examination (Fig. 10) of the tensile tested specimen showed a complete absence of grain boundary cracks.

We have found that if the U(IV)/U(III) ratio in fuel salt is kept below about 60, embrittlement is essentially prevented when CrTel.266 is used as the source of tellurium.

They recorded a crack depth of 0, and very minimal cracking for other sources of Te.

The evolution of fluorine gas was solved in 1970 [moltensalt.org] by putting insulation (a reflective layer) around it.

Nevertheless it is clear that prevention of fluorine evolution from stored MSR salt will not be very difficult or expensive,

A decommissioning process [nap.edu] was developed in 1997 and the original MSRE, without the later developments, improper defueling and storage and all, was decommissioned [doe.gov] and now serves as a source of thorium for medical research at present. The original decomissioned procedure in 1969 was simply to turn it off and walk away. So we don't do that anymore. Wiki [wikipedia.org] summaries:

Cleanup of the Molten-Salt Reactor Experiment was about $130 Million, for a small 8 MW(th) unit. Much of the high cost was caused by the unpleasant surprise of fluorine and uranium hexafluoride evolution from cold fuel salt in storage that ORNL did not defuel and store correctly, but this has now been taken into consideration in MSR design.

If the fluoride fuel salts are stored in solid form over many decades, radiation can cause the release of corrosive fluorine gas, and uranium hexafluoride.[94] This was due to radiolysis of the salt from remaining fission products, when colder than 100 degrees Celsius.[79] The salts should be defueled and wastes removed before extended shutdowns. Fluorine and uranium hexafluoride evolution can be prevented by storing the salts above 100 degrees Celsius.[79] Because some of the fission product fluorides have high solubility in water, fluorides are less suitable for long term storage. For longer term storage, fluoride containing wastes could go through a vitrification process to be encased in insoluble borosilicate glass suitable for long-term disposal.

Corrosion from tellurium—The reactor makes small amounts of tellurium as a fission product. In the MSRE, this caused small amounts of corrosion at the grain boundaries of the special nickel alloy, Hastelloy-N used for the reactor. Metallurgical studies showed that adding 1 to 2% niobium to the Hastelloy-N alloy improves resistance to corrosion by tellurium.[24](pp81–87) One additional strategy against corrosion was to keep the fuel salt slightly reducing by maintaining the ratio of UF4/UF3 to less than 60. This was done in the MSRE by continually contacting the flowing fuel salt with a beryllium metal rod submersed in a cage inside the pump bowl. This causes a fluorine shortage in the salt, reducing tellurium to a less aggressive (elemental) form. This method is also effective in reducing corrosion in general from the fluoride salt, because the fission process produces more fluorine atoms freed from the fissioned uranium that would otherwise attack the structural metals.[92](pp3–4)

Radiation damage to nickel alloys—The standard Hastelloy N alloy, a high nickel alloy use