The amazing story of how a young Jimmy Carter helped avert a nuclear disaster

[NNadir]

6. The major radioactivity of failed fuels is associated with short lived nuclides.

I remarked on this some time back in connection with the elevation of worry about what could happen at the Ukrainian Reactor being in danger of being shelled by the Russians, and is still a big deal to many people whose fear that something nuclear might happen, and which takes attention away from the fact that actual deaths are taking place because of fossil fuel based weapons of mass destruction that were funded by fossil fuel sales to antinuke Germany:

Some comments on the war situation with Chernobyl as well as the operable nuclear plants in Ukraine.

In it, I referred to a Master's thesis on the decay properties of used nuclear fuels, an excellent Master's thesis, one of the best I've ever read:

For the first 24-48 hours after shutdown there is major decay of short lived nuclides like Np-239 & U-239. These produce a lot of heat, and thus can and do cause fuel to melt in solid phase fuels.

The issue is not volatilization of the actinides, which have low vapor pressures, but rather cesium iodide, strontium oxides and iodides etc.

Iodine is the most dangerous fission product.

One can learn about fuel properties after shutdown by reading Dr. Kristina Yancey (Spencer's) 2013 Master's Thesis:

https://catalog.library.tamu.edu/Record/in00003477980

See figures 20 and 21 on pages 58 and 59, respectively.

If the containment is breached, and the pumps are destroyed by the barbarians, the result may be more like Fukushima than Chernobyl. Chernobyl was worse because the graphite core burned. These reactors, I would guess, but do not know, are VVERs They will have a negative void coefficient in a Loss of Cooling event.

The Russians have descended into pure savagery if they are doing this. A deliberate Fukushima as I am prone to point out, will pale in comparison to climate change however.

The figures from the thesis to which I refer at these which refer to the decay of the shorter lived (and thus highly radioactive) isotopes and the longer lived isotopes:



The caption:

Figure 20. Total heat load of all the spent fuel from operating reactors for each of the
reference times used in the Spent Fuel Database, shown with a logarithmic vertical axis.

The caption:

Figure 21. Composition of the total heat load of all the spent fuel from operating reactors after (a) 0 years and after (b) 20 years.

The thesis contains similar representations of the decay rates with respect to radiotoxicity with ingestion but of course, neither Jimmy Carter nor any of the other hundreds of liquidators in 1952 ate the fuel.

I would question what you mean by "safe." Obviously going into the reactor core was safe for Jimmy Carter; he lived to be a hundred, something I'm sure not to do. Of course, he went in only for a very short time, like all the others. There is no doubt that it would have been "safer" for him and everyone else if they waited a year or so before going in. The thing was, I guess - I wasn't born yet - that they were in a rush to do something, since they wanted to get the reactor going again, which they did within two years of the melting event.

There weren't a hell of a lot of nuclear reactors in 1952, and I'm sure that the scientists and engineers involved in nuclear research wanted to keep those that could be kept going on line.

The contaminated area was fairly small, as evidenced by the fact that the reactor was repaired and restarted and operated for more than 4 decades.