Nothing to say aboutthe column. I just wanted to congratulate Slug for some of the most gratuitous accompanying artwork ever.
Excelsior!
Why, she had hardly any Bikini Atoll!
I would like to comment on the article.
I think the author should really research the subject a little further. The reason contaminated steel is less valuable is because the contamination makes neutron embrittlement more likely, which makes the steel suspect or useless for many applications. When recycling, any contaminated material will contaminate the whole batch which may otherwise have been acceptable.
It has little to do with the health hazards of the material, which seems to be the point insinuated in the article.
I don’t think Cecil was suggesting that at all. The reason given for needing radiation-free steel in the article was for supporting sensitive radiation-measuring experiments. If you’re trying to measure a particular person’s radiation exposure very precisely, you want to be sure that all of your Geiger counter clicks are coming from that individual, rather than the environment. So you shield the target from the environment, naturally–except that this doesn’t help if your shielding itself is radioactive.
I strongly doubt that contamination from atmospheric radioactives introduced in smelting has a significant impact in the strength of the metal. But I’d be happy to read any cites you may have …
You are absolutely correct. In a review of scores of sources on this subject which I and Cecil did, neutron embrittlement was never even mentioned in passing as a possible reason. I will not deny someone, somewhere may think there is something to it, but it certainly would be on the very fringes of the topic.
We will be posting the references for the column tonight, FYI.
Why can’t you just take a reading of the background level of radiation without your test subject present, and then subtract that from the reading you get with the test subject present? I do not think Cecil has really explained why these testing rooms needed to be shielded at all, let alone why special, uncontaminated steel would have been needed. (My guess is that they were really needed for something like calibration of the Geiger counters, rather than measuring the radiation exposure of individuals, but I really don’t know.)
I think you are confusing two different things here. The type of radioactive contamination refereed to in Cecil’s article occurs in when the oxygen lance is used during the steelmaking process, introducing the occasional radioactive cobalt or other atom. Cobalt-60 is a beta-emitter and decays to nickel, which can emit gamma rays. No neutron emission at all.
Neutron embrittlement occurs only when an alloy is exposed to high-intensity neutron radiation over time. It is mainly a concern in engineering nuclear reactor components.
I have a different nit to pick.
Cecil wrote:
Why bother telling us this without giving the results of testing - some of which must have be done - of what the actual effects were?
Well, you’d kinda need a twin earth where 500 above ground A bomb tests had NOT been done to compare with the Earth we live where it had been done to validate those estimates…
Failing that, you could figure out the incidence of genetic, bone, and bone marrow disease in children born during that period, compare it to older periods, and impute the difference to radiation. I bet somebody did that.
Oh, you could. And like you said somebody probably did/tried. But the factors you would have to correct for statistically would be pretty “bad”. Particularly if you are looking for a small 5 percent increase in something not exactly common.
Think how much the world changed in the few decades before rampant above ground bomb testing and a few decades after the testing.
IMO it would be a statistical nightmare.
It is a difficult problem, but the basic techniques are well established. If not, then we could know nothing whatsoever about longitudinal incidences of any disease. But we do. There have been thousands of studies of every kind.
And, of course, your objection would logically also apply to the scientists who were making the prediction in the first place. How could they possibly assert any number at all unless they had a means of estimating current cancer rates? Or do you think they were plucking a number out of the air and assuming that no one would ever bother to check their statements?
Show me/us the studies and results and we will all be happy. I don’t doubt they exist. I also don’t doubt it wasn’t easy to do either. And I still imagine for many studies you can still pull a “hey, it wasnt radiation that caused the change, it was some other XYZ that did”
As for the scientist, all they have to do is assume that exposure to radiation and certain cancer rates is linear with exposure level (and they don’t even need humans, lab rats will do in a pinch). Not exactly precision science, but it certainly is is a decent back of the envelope calculation and far from pulling numbers out of thin air. I never said the scientist pulled the numbers out of thin air BTW. I said it would be hard to measure.