First Fuel Produced for the Idaho National Lab's Experimental Molten Salt Reactor.

[NNadir]

2. I confess I do not have a detailed understanding of this particular reactor. There are so many interesting ideas...

...floating around that we are seeing what Weinberg described, referring to the 1950's and 1960's as "the first nuclear era."

Happily we are seeing a third nuclear era; it couldn't come at a better time other than say 20 years ago. (The 2nd nuclear era was the commercial era of light water reactors, with a few wonderful heavy water reactors thrown into the mix. Fast reactors in that era were not spectacular successes with the exception of the Russian reactor.)

Let me speculate on the case described in the OP:

This is deemed an "experiment." It is unlikely therefore that it will be equipped with devices for exergy recovery, Brayton or otherwise. The only experimental reactor ever hooked up to exergy recovery to my knowledge was when Enrico Fermi lit up a light bulb using power from one of his early reactors. (It was a kind of pointed joke, I think.)

I'm a big fan of Brayton cycles as a first step in process intensification to achieve high thermodynamic efficiency, but that is not, I think, the goal of this effort. The goal will be to understand issues in fuel performance - and as my son and I often discuss, what falls by the wayside too often - materials science.

I note that a Brayton cycle is generally limited to merely generating electricity. If we are to eliminate all fossil fuels, particularly petroleum, we need a broader mission for the heat.

We are entering a golden age of materials science and hopefully this will play a role in the experiment. It should; it must.

The original Weinberg MSR relied on nickel based alloys, either Inconel or Hastelloy; it slips my mind which is the case. Through my son I learned about a big neutronic issue with these alloys that may have been missed because the reactor did not operate that long.

There was no mention of thorium in the news item cited in the OP. I personally believe thorium is a key to eliminating the need for enrichment, but I'm not, or no longer am, a LTMSR kind of guy. For various reasons I don't like FLIBE although I'm very fond of other fluoride salts. (I also don't like beryllium.)

I believe that the ideal use for thorium is in ceramic or metal fuels in the presence of depleted or, better, once through, uranium obtained from used nuclear fuels. I'm not sanguine about pure ²³³U. Because of the geochemistry I believe that uranium is inexhaustible, even if there is more thorium in terrestrial ores. A lot of the "thorium is better than uranium" claims don't hold up to inspection to my mind.

To be perfectly honest, these days I'm rather fond recently of liquid metals - not necessarily sodium - which is a change for me that came only in recent years.

But look, this is a time for nuclear creativity. We know a hell of a lot more than we did in the 1960s, but we can build upon what they did then by applying this new information. We also have much advanced computational power. A computer you can buy at Best Buy or Walmart or wherever, is way more powerful than the best computers of those times. In a way, this is a measure of how brilliant the people of that era were, on the other hand, they were less constrained by radiophobia. I recently read an account of the first fast reactor ever built, the mercury cooled "Clementine" reactor. The author of the article remarked it would cost billions of dollars to build today, not because it would be difficult to build, but because of all the bureaucracy involved. They built and operated the reactor in the late 1940's. It took a few months to build, and they operated it for a few years, before dismantling it when it started to look tired.

Interestingly many of the reactor pioneers, certainly not all, lived relatively long lives. Weinberg himself, despite standing next to the isolated ²³³U in the famous picture, lived to 91. (Fermi died young; but he was something of a cowboy; the world's most brilliant cowboy, but a cowboy all the same. The control rods on the Chicago Pile were held by ropes by people standing on the core. In Italy he was playing with neutrons well before anyone else was other than, say, Chadwick. Chadwick lived into his 80s.)