Metal scavengers are taking apart Prince of Wales and Repulse

[MrRiplEy[H]]

And £57,000 wouldn't even pay the transit time for a western salvage ship and crew. Only poor people would try to salvage a wreck like that. There are thousands of wrecks laying on beaches and close to shore around the world that are not worth salvaging, except for local scavengers.

(Image removed from quote.)

Hey I resent that! Why would you put the picture of my fine yacht on like that? It just needs a bit of paint, that's all.

[MrRiplEy[H]]

From what I understand, part of the value of wreck sites like these is that they were constructed and subsequently sunk before any nuclear weapons were set off, which means they have about a 7% lower contamination rate than any steel forged after August of '45. Steel like this is valuable for use in Geiger Counters and some medical devices. That's why the Scapa Flow fleet, the US Reserve Fleet, and sites like this one are so prized.

How does the contamination get to the fresh iron ore mined from the ground? I've heard that certain types of metals (lead for example) decay over time so that the salvage metal is very precious. It has nothing to do with nuclear testing however, it's just the fact that the ingots are stored so long in the bottom of the sea.

http://phys.org/news/2013-11-controversy-roman-ingots-dark-neutrinos.html

[Muzzy]

How does the contamination get to the fresh iron ore mined from the ground? I've heard that certain types of metals (lead for example) decay over time so that the salvage metal is very precious. It has nothing to do with nuclear testing however, it's just the fact that the ingots are stored so long in the bottom of the sea.

As I understand it, steel forged from 1945 onwards has higher levels of contamination because the repeated use of nuclear weapons has released a lot of radioactive materials into the atmosphere. These airborne contaminants get mixed into the steel during the forging process and there's not much that can be done to prevent it. Steel that was forged pre-Hiroshima will have 7 percent less contamination because it was forged in a cleaner atmosphere.

[PR3D4TOR]

No longer the case since the ban on nuclear testing.

[Muzzy]

Yeah but the half-life of some of those substances runs hundreds of years. The levels are still significant enough to affect sensitive instruments made from post-nuclear steel.

[PR3D4TOR]

No, they have been reduced to 0.5% of background radiation.

[guncrasher]

As I understand it, steel forged from 1945 onwards has higher levels of contamination because the repeated use of nuclear weapons has released a lot of radioactive materials into the atmosphere. These airborne contaminants get mixed into the steel during the forging process and there's not much that can be done to prevent it. Steel that was forged pre-Hiroshima will have 7 percent less contamination because it was forged in a cleaner atmosphere.

muzzy, I work at a steel mill.  Would like to know your sources,  I'll check on this.



semp

[Muzzy]

Mostly just looking up different sources on the internet. That plus some discussions with physicists some time ago. If you do a search on radioactive steel and "scapa flow" you'll get a bunch of articles on the subject.

[PR3D4TOR]

http://en.wikipedia.org/wiki/Low-background_steel

[guncrasher]

Mostly just looking up different sources on the internet. That plus some discussions with physicists some time ago. If you do a search on radioactive steel and "scapa flow" you'll get a bunch of articles on the subject.

I wont do the research for you.  you made a statement, please do explain .


semp

[guncrasher]

http://en.wikipedia.org/wiki/Low-background_steel

it says that current steel is back to normal.


semp


here's one of the sources quoted on your link

http://www.straightdope.com/columns/read/2971/is-steel-from-scuttled-german-warships-valuable-because-it-isn-t-contaminated-with-radioactivity

[PR3D4TOR]

Correct.

[pembquist]

I know nothing about the subject except what the wiki says and it doesn't say normal it says 1/2 a percent above normal. So...it isn't back to normal but are ya'll saying it is close enough?

[guncrasher]

"Maybe you're thinking: at last, a use for that pocket battleship I inherited from Mom. Sorry, the market for old steel is now pretty much sunk. Reduced radioactive dust plus sophisticated instrumentation that corrects for background radiation means new steel can now be used in most cases. There's some lingering demand for really old maritime metal, though. When researchers at one national lab wanted shielding that emitted no radiation whatsoever, they used lead ballast retrieved from the Spanish galleon San Ignacio, which had been lying on the bottom of the Caribbean for 450 years."


that is the last paragraph from one of the sources quoted on wikepedia.


semp

[MrRiplEy[H]]

Salvaged lead is especially pricey because lead naturally contains an isotope that prevents its use as a shielding material in measurement devices. The ancient Roman lead salvaged from an old wreck has decayed sufficiently enough to serve as shielding.

WW2 era wrecks do not apply however in this case.