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Jack Devanney's avatar

Guys,

Some good comments. Collective response to all the comments to date.

Masks

Doubt if the Covid 19 experience applies. Since radiation damage is not contagious, there would be no social pressure to mask up, The Release Pamphlet will make it quite clear that masking is completely voluntary.

The iodine and cesium aerosols in a radioactive release have a mean diameter of roughly 3 microns. From memory, the Covid virus was much smaller, about 0.1 microns. N95 masks can be pretty effective IN THE FIELD against 3 micron particles. See for example Figure 7.2 in the Underwriter Certification Manual. Yes, there will be leakage. But if your harm model is SNT, then cutting the dose rate by a factor of ten, resulting in cutting the harm by more than a factor of 100. Pretty compelling numbers.

600 year SNF

AFAIK, the 600 year number goes all the way back to mid 2022 when it was introduced in the 2nd Edition of Why Nuclear Power has been a Flop. It was included in one of the first pieces on this sustack in late 2022. I did not understand why I had never seen the penetrating/non-penetrating distinction made before that but figured that once somebody pointed it out, pro-nukes would jump all over it. This has not happened. I dont know why.

I have had people tell me that Joe Sixpack is too stupid to understand the difference between penetrating and non-penetrating radiation. Most of my friends are Joe Sixpacks. They have no problem at all understanding the simple argument. The people who make this argument are the stupid ones.

The 600 year number comes from a graph in an NWMO study of a Canadian Repository which I redrew and relabeled. This is referenced and discussed in the PDF version of the substack piece which you can and should download from https://gordianknotbook.com/download/nuclear-waste-a-tale-of-two-particles/

The NWMO study does not do a very good job of saying exactly how they calculated the dose rate at the fuel element surface. Doing the calc myself has been on my todo list for quite a while. Maybe this will prod me to get this job done. But a quick check is possible. From year 50 on, the gamma dose is total dominated by Cesium-137 with a 30 year half-life. 600 years is 20 Cs-137 half-lives .5**20 is 9.5e-7. After 600 years, the Cs-137 is down by a factor of a million.

All fissions whether it be U-233, U-235, or Pu-239 produce about the same amount and spectrum of fission products (gamma emitters) for the same amount of thermal energy. ThorCon and other thorium burners has no advantage here. The whole point is that any difference in alpha emitters is totally unimportant from the waste handling point of view. High thermal efficiency designs do have a waste amount advantage on a electrical output basis. ThorCon has an overall thermal efficiency of a little over 45%; a standard LWR is abound 33%. So 40% less waste/Mwe. Important economically but not really important for present purposes.

Threshold

The Non-threshold Model which the Gordian Knot Group is advocating is called Sigmoid No Threshold. It and our damage repair processes are discussed extensively in various GKN pieces. But if you are really serious, you should study the The Underwriter Certification Manual which you can download from https://gordianknotbook.com/download/underwriter-certification-of-nuclear-power

All my stuff is under the Creative Commons A4 license which as far as I can tell means you can do whatever you want with it except sell it.

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Sean's avatar

The masking point is new to me, that's very interesting and good to know. Thanks.

I often see the 600 year fact in these conversations so I would disagree that this is universal. I do see some pro nuke people argue for a permanent repo but they argue it is easier to do this as a 'PR' win than it is to educate the public. I think this is an incredibly dumb way to fight that battle. Not least of which is that it means the opposition can continually invent new hurdles for you to clear.

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