Why no talk about nukes?

You’ve made a number of good points, OtakuLoki, but I want to nitpick this one.

It’s my understanding that reactor pressure vessels are far more robust than submarine hulls (then and now). I’ve never heard that the Thresher reactor vessel or core are in pieces. Do you have anything to support this contention?

Regarding your other point, I’m certain that the core is filled with salt water, of course.

–robby (ex-nuke)

P.S. My Google-fu is high today; I see that you were a skimmer ELT. I was a bubblehead, but went through D1G for prototype.

I didn’t know that nuclear plants generate about 20% of the electricity in this country. I thought it was lower.

I’ll admit I have no concrete evidence. However, given that the plant was at operating temperature and pressures when deep sea water was admitted into contact with the pressure vessel I cannot imagine that the reactor vessel would be able to remain intact given the combination of pressure and temperature shocks. Just remember the concern that we had for brittle fracture curves.

And remember that regular boilers on surface vessels have a distressing tendency to blow up when ships sink. It doesn’t always happen, but it’s very common.

Given all this, and the violence that a test depth crush would do in the first instants of the casualty, I think that it’s quite reasonable to assume that nothing that had been contained in the hull of the Thresher is intact - certianly not the core nor the reactor vessel.

And glad to see another Nuc here. Normally I’d make cracks about bubbleheads, but two things are stopping me: first off, my normal crack just doesn’t seem proper while talking about Thresher; secondly - no matter what names I might call you - y’all bubbleheads have the better insult for us surface fleet people - Targets. :smiley:

Saw my buddy the geologist the other day, and asked him about his concerns. Thought I would toss them up here since I mentioned them before. Caveat - the following is a lawyer’s paraphrased recollection of a rather brief conversation yesterday. Regarding accuracy on any particualr point, my friend may have been full of it - or I may have misremembered what he said.

Me: I was in a discussion c/o YM, and recalled that you had expressed some misgivings about YM.
Him: Absolutely. Because it is a welded tuff. (Which he proceeded to explain to me). It has 8-9% porosity, most of which is filled with water. The waste to be stored will generate heat. Should the water get heated sufficiently to turn to steam, it will fracture the tuff.
Side shafts approx 1-2’ in diameter have been drilled perpindicular to the main storage tunnels, with sensors in them. These shafts are currently draining up to 5gal/second.
As a result of these concerns, they have widened the tunnels from the original ~ 15’ to 20-25’, and intend to place the containers more widely than before.

Me: Is this calamity going to occur overnite, in a million years, or somewhere in between?
Him: Geologists tend to avoid predictions > 10,000 years. He’s cynical enough to think the human race is sufficiently stupid that he has little faith in the species lasting that long. So YM is probably OK.
Instead of YM, he is more concerned about the ongoing practice of deep injection of hazardous waste with insufficient consideration of migration patterns…

And on this cheery note, we parted. Discussions with this guy always brighten my day so!

Okay - I’m not about to doubt his geological knowledge, or understanding. That’s all waaaay beyond the scope of my clue. I’m also more than a little concerned about a 5 gal/second flow rate. Leaving aside flooding issues, I thought YM was in a salt deposit - so if it’s getting that much water flow, won’t it begin to dissolve rapidly?

I do have questions about the ability of the waste to heat water to steam. As a general rule, the waste we’re talking about storing in YM has been sitting in short-term storage pools for a considerable period of time, years, and decades in some cases. That doesn’t eliminate the concerns about contamination, nor exposure. However, that time frame does allow for a lot of the shorter half-lived isotopes to decay to very small fractions of the concentrations that they’d have been present in the fuel at shutdown. And with it, eliminate the need for active cooling to control decay heat.

Hmm, bear with me a moment while I work out how I want to tap dance, here. As always, my desire to stay out of Leavenworth will moderate how I phrase my arguments.

Decay heat is a very real concern. It is both the reason that a shut down reactor plant will have coolant flowing through the core, and part of the reason that the short term spent fuel storage pools are so large: to provide a large heat sink for the spent fuel cells. (The other reason being that water is about the cheapest shielding materiel available.)

I accept that the decay heat for the glass that they’re planning to store at YM is signifigant. I don’t think that it’s going to be enough to get above boiling. I seem to recall the equilibrium temperature for the pilot plant was about 140 F. That sounds reasonable to me. That’s also a fair estimate of the highest temperature that the decay heat will get to. It’s not that I think that there’s an upper limit to the temperature that one could get from decay heat - if one has enough of any given isotope decaying, it’s can raise temperatures to phenomenal levels. I do think that, given what I recall of the isotopes in spent fuel, for every atom of fissionable material that had been enriched during plant life, there’s two or three isotopes that will be acting as fission poisons - that is an isotope that eats neutrons without releasing anything but a little gamma. (The ultimate poison is hafnium, because it has so many isotopes that eat neutrons, then go on, in the new isotope, to eat more neutrons.)

The point is that I find it very hard to believe that it would be possible for the waste to go reach criticality, and without that happening, it’s a fair to assume the following: the highest concentration, and largest absolute amount of radioactive isotopes in the treated spent fuel to be stored in YM will occur at the time of deposit. From then on, it’s a downward slope. And, at first, a relatively rapid one. As a corollary to that first assumption, the highest heat flux, and, thus, the highest equilibrium temperatures, will also be found shortly after deposit.

While I know of some decay chains that go from a long-lived, low-energy decay reaction to a short-lived, high-energy decay reaction, they are very rare. And, more importantly, since the production of the shorter isotope is controlled by the first isotope’s own decay reaction, the equilibrium concentration will be (IIRC) lower than the initial concentration of the first isotope.

Dinsdale, thanks for reporting what your friend said. I hope that my post can answer some of the issues brought up. And that it’s clear about the things brought up that worry me, too.

What annoys me is that YM is a project based on a test project done here in NY, in one of the many salt mines around here. With the exception of the salt mine collapse in Mt. Morris a few years they’ve been stable for eons. And that one failed because the mining engineers/supervisors cut out too much of the deposit to leave it self-supporting.

I can recognize that there’s no way my fellow NYers would vote for anything that allowed a facility the size of the YM facility to be put in our backyard - but I’d imagine that the geological surveys that are causing problems at YM had to have been done for the pilot project here, first. There could be valid reasons for not expanding the pilot project, but my gut instinct is to look for NIMBY to be at the root of it.

He was adamant about the volcanic welded tuff nature of YM. I recall in previous discussion we talked about the stability of salt domes.

This is the 2d time he has brought up the issue of hazardous waste injection. If it is as unscientific and widespread as he suggests, I’m surprised it doesn’t get more press.

OtakuLoki, you’re thinking of the WIPP. That is indeed a salt formation here in southern New Mexico. But it doesn’t handle the kinds of stuff Yucca Mountain is intended to handle.

Dinsdale, I’m not about to claim your friend is mistaken about his expertise. If he’s saying it’s welded tuff, that’s good enough for me.

asterion, actually I was thinking about this facility, instead. Not quite as high-grade a waste disposal facility as I thought, but definitely part of the development projects behind WIPP and YM.

If you remember the Silkwood story the company not interested in safety but in profits coverered up inferior welds. The short term profits will outweigh the long term safety. There are many thousands of pumps ,elbows electrical components etc.They all have to be right.you have to trust the contractor.(halliburton) I don’t.

Fusion? If we could make fusion work, what would be the point of extracting oil from tar sands?