'It's the future': How going small may fuel nuclear power's comeback

https://www.cbc.ca/news/business/nuclear-power-small-modular-reactor-1.5188048

Canada is positioning itself up to be a leader in a new age of nuclear power by exploring the use of small modular reactors (SMR).

"It's the next wave of innovation. It's the future of the Canadian nuclear sector," according to Diane Cameron, director of the Nuclear Energy Division at Natural Resources Canada.

 

I watched this a couple of days ago. Nuclear energy is fundamentally safe, for commercial use, But, There are old stigmas and biases that prevent its use on the commercial market. Primarily, The interests of the governments don't want nuclear materials falling into the hands of citizens. It's not so much a health issue, as it's a national security issue.

To be blunt, World governments don't want common people to possess the power to resist their tyrannical directors, They confiscate guns whenever possible, The purposes of world government isn't to keep the people safe, It's to keep them so powerless they could never fight back.

 

The last time I looked there is starting to be a radioisotope problem because the small research reactors that generate them are aging and shutting down. Pu 238 is prepared by irradiating Np 237.

These nuclear generators typically use Pu238 (actually PuO2, a ceramic) with a half-life of 87 years so the temporal power degradation is mostly due to the generator end (thermocouples or whatever degrading).

A power generation section that doesn't degrade would be really helpful.

 

Am I wrong here? I thought 238 was weapons-grade uranium? I thought reactors used 235, I'm not suggesting, I'm literally asking because I don't know.

 

Not hardly.

Weapons-grade nuclear material - Wikipedia
"Standard weapon grade plutonium requires a Pu-240 content of no more than 6.5%." which is 65,000 PPM, and the analogous Pu-238 was produced in levels of 0.5% (5000 PPM) or less).

Weapons grade plutonium is made in research reactors by exposing U238, removing it, waiting for the U239 to turn to Pu239, separating it, rinse-lather-repeat, since it isn't practical to separate Pu238, Pu239, and Pu240.

Pu 239 has a half-life of 24,110 years.

You want a long half-life so the pit doesn't spontaneously detonate during the compression phase, but only when triggered at peak compression by what is effectively a tiny atom smasher (a neutron source). Also the short half-life elements would make the warhead too radioactive to maintain and unreliable.

A primary only detonates for about 60 ns. The energy released starts driving it apart at that point and you want maximum efficiency.

The parts of the pit are accelerated to 200 km/s (almost 1/1000 of the speed of light) in about 2 meters.

The secondary is a short distance from the primary so the prompt and xray radiation compress it and the neutron radiation fuses it before it gets hit by pieces of the primary.

As a side note - the pressure (mostly radiation pressure) compresses the secondary 1:10 in 3 dimensions (a secondary the size of a soccer ball gets compressed to the size of a golf ball).

50,000 times the pressure of the RDX/HMX used for the primary.