Recently I have watched a number of interesting series videos on the topic of nuclear physics, and its applications in peace and war.
This is one of Anton Petrov’s videos which I follow to get news of what going on in science, especially astronomy. I have learnt quite a bit from this one, where in regard to history it comes across that The Oak Ridge Laboratory was working on thorium reactors, but because of the Cold War the funding was directed to fast breeder uranium reactors to produce plutonium for bombs.
It received some corrections from a commenter MrElifire84, of which the two are the most significant are these (abridged):
- Graphite Rods aren’t used to slow the reaction down. They are actually used to speed it up. Their function is to slow down the neutrons born in fission. Slow neutrons have a higher probability of fissioning other nuclei than fast neutrons. . .
This one goes on to give a good and concise explanation of moderators vis a vis control rods.
- Thorium isn’t a Nuclear fuel. It is a precursor. Kind of like wet wood isn’t good fireplace fuel. It needs to be dried first. The actual nuclear fuel in a thorium MSR is Uranium isotope 233. This is created by thorium 232 capture of a neutron to become thorium 233 and then through atomic decay turning into Uranium 233. This process is known as “breeding” wherein a “fertile” isotope is “bred” into a “fissile” isotope to become your fuel. This is the same process used to breed Uranium 238 into Plutonium 239 in other reactors that rely on Uranium 235 as fuel.
Here again, worth reading the whole comment, especially as regards the waste problems with plutonium.
This is an interesting video in the Period Table of Videos from Martin Poliakoff. From the article in Britannica one learns that it
was first produced by intense neutron irradiation of uranium-238 during the detonation of nuclear weapons. This isotope was identified in December 1952 by Albert Ghiorso and coworkers at Berkeley, California, in debris taken from the first thermonuclear (hydrogen bomb) explosion, “Mike,” in the South Pacific (November 1952).
which the video describes in detail, and goes on to describe how researchers have managed to synthesize and study a remarkable chemical complex from the tiny amount of material available from nuclear reactors.
This next one came up in my YouTube recommendations, and is one of a series from Fermilab which aims to clarify those mysterious particles, neutrinos.
A video well worth watching, but wanting to understand more I went a-searching on the web, and found this PDF:
Bruno Pontecorvo and modern neutrino physics by S. M. Bilenky, with the double address at the Joint Institute for Nuclear Research at Dubna, Russia, and the Physik-Department, Technische Universität München in Germany. Dubna is celebrated in the name of dubnium, a synthetic transuranic element with atomic number 105. It is well worth even just looking at to get an idea of how “hairy” neutrino physics is.
The name Pontecorvo rang a bell, because he disappeared while on holiday in Italy after the arrest in 1950 of Klaus Fuchs | German physicist and spy (Britannica) whose espionage is credited with saving the Soviets at least one year’s work in their own program to develop the atomic bomb.
It became known in 1955 that Pontecorvo had defected to the Soviet Union and was working at Dubna. It is still unclear whether he was simply a devoted communist or was actually a spy, see Nuclear physics: New light on a cold war conundrum (Nature).
However, in recent years Oak Ridge and Dubna have come together, with the discovery in 2006 of oganesson (element 118) and in 2010 of tennessine (element 117). The name oganesson honours Yuri Oganessian, a leading Russian-Armenian nuclear physicist who has played a large part in the discovery of superheavy elements while tennessine celebrates the University of Tennessee and Oak Ridge National Laboratory which have been major collaborators in this investigation.
I was watching this video, where it is explained that heavy water tends to absorb neutrons very strongly, while heavy water does not. Therefore heavy water could be used as a coolant to prevent the uranium from overheating.
This rang a bell. During the years shortly before I retired, I would visit the Rutherford Appleton Laboratory to take part in neutron scattering experiments on polymers. For this we would use versions of organic solvents in which the hydrogen had been replaced by deuterium.
And finally, one especially for British readers .