This doesn\’t sound right

Some of the instruments which tell commanders about the state of the nuclear reactor were also feared compromised, the Guardian can reveal. The detectors which measure the power coming from the reactor are in a lead-lined water jacket that surrounds the reactor core.

The lead has to be \”virgin\” metal, mined from great depth, so that it does not carry any electrical charge of its own that could generate a false reading.

However, the lead used in Astute was not of the right quality, which means instruments gave incorrect readings. Using impure lead can also have a knock-on effect during maintenance – the charged metal can create increased and persistent radioactivity within the reactor compartment.

I\’m really not sure what is being said there at all.

You might want \”deep mined virgin lead\” to get away from having contamination with the residues of atmospheric testing of nuclear bombs. Or you might want to have lead which itself is not radioactive. In which case you don\’t want virgin lead at all. You want old recycled lead. The stuff stripped off medieval churches is good for this. For the lead-210 present in all newly made lead will have decayed.

But I\’m really not sure how that could lead to \”electrical charges\”. Anyone actually know this area and care to explain it to us?

18 comments on “This doesn\’t sound right

  1. Using impure lead can also have a knock-on effect during maintenance – the charged metal can create increased and persistent radioactivity within the reactor compartment.

    I am not an expert but I sometimes play one on the internet and I don’t know what the hell they mean either. I assume that is a reference to lead with impurities. Lead is rarely found on its own and if it is not refined enough it may have other metals present. Which may become radioactive and emit. Lead is usually found with copper, zinc, and silver. Many radioisotopes of zinc decay by emitting a beta particle and an electron – is that what they mean?

    On the other hand, this:

    “The stuff stripped off medieval churches is good for this. For the lead-210 present in all newly made lead will have decayed.”

    Lead-210 doesn’t decay if it is under the ground?

    What is interesting about that article is the near universal joy at the discovery of problems with the submarines, coupled with an equally nearly universal ignorance of the scientific illiteracy of the author. That is the modern British Left for you – they will believe any superstitious rubbish as long as it makes Britain look bad.

    Tim adds: “Lead-210 doesn’t decay if it is under the ground?”

    Lead 210 is the last but one product of the decay of U 238. And there’s always a bit of that around in the ore. So any lead ore will have some lead 210 in it. The U which would create more of it is discarded when you first purify the lead. Therefore already purified lead has 210 in it, but no more being added. Therefore over time it becomes free of 210 pollution.

  2. It sounds like bollocks, I wonder if they are confusing this with with the use of steel that was made before the atomic testing started and so has no trace radioactivity (or significantly less of it).

  3. Complete bollocks.
    “… The detectors which measure the power coming from the reactor are in a lead-lined water jacket that surrounds the reactor core.”
    How can you measure power output, wattage in SI units, without connecting to the, um, ouput shaft(?) to measure it?

    “.. the charged metal can create increased and persistent radioactivity …”
    An electric charge causes radioactivity? Rilly?

    Life’s too short to read the rest of it.

  4. Watts are joules per second, you can presumably just measure the heat energy of the reactor. Measuring the shaft (ooer, mrs) would be measuring the output power of the generating plant, not of the reactor core.

  5. Oh, it’s a submarine. That’ll teach me to comment without even looking at the article.

    Anyway in that case measuring the shaft would be measuring the output of the engine, not of the reactor.

  6. VftS : I suspect they are referring to either the thermal or radioactive flux inside the reactor. Not output power after the heat has transferred via the primary and secondary loops and the steam turbines. Yes, a little knowledge is a dangerous thing, especially when the Gruandiad is involved :-)

  7. Tim adds: “The U which would create more of it is discarded when you first purify the lead. Therefore already purified lead has 210 in it, but no more being added. Therefore over time it becomes free of 210 pollution.”

    I stand corrected.

  8. Beta and alpha radiation are charged and will cause a charge to be transferred from the emitter to the absorber, being electrons and helium nucleii (as is anti-beta as it is positrons). So they could be referring to that.

    Or they could be referring to electrochemical effects from metals of different composition/poorly alloyed metals, which can separate out as the metal cools and crystalizes.

  9. I wasn’t a back nasty but I had to learn to play one – and we had radiation detectors forward of 109 bulkhead too. And it seems to be utter bollocks.

    The speed thing is highly misleading too. The carriers will need to have a fast sprint speed – it helps for launching aircraft. But, as we chose not to have nuclear powered carriers, their normal speed will be lower (and our modern escorts aren’t as fast as the older ones either.) Of course, the nuclear submarines will be able to sustain close to their max speed pretty much as long as necessary.

  10. I still don’t understand why the government didn’t just buy some American nuclear carriers instead of insisting on designing our own inferior ones. Why the hell aren’t they nuclear, for a start?

  11. Ian,

    Where was the Prime Minister’s constituency? And the Secretary of State for Defence’s?

    As to the nuc thing, the wavey-hand people might have had to let some nasty smelly submariners on to their floating cocktail party to keep it running … Also, to be honest, they are rather pricey. And we’d probably have to have designed new reactors – which would have been even more pricey (the Enterprise class uses multiple sub reactors but the 5 other planned ones were cancelled and the follow-on Nimitz class just has 2 specifically designed ones.)

  12. Virgin metal? I think they’re trying to imply Either recently refined or they’re trying to imply that lead is a noble metal?
    They seem to be implying that you can find lead in its pure state really deep under the ground. Sounds like crap to this materials engineer

    But if the article is true, that does seem like some shoddy work. I’m starting to notice that military industrial complex stuff can be pretty glitchy. But if you’re just making say 5 machines its a hell of alot different to making millions of BMWs. Sort of to be expected really

    Ah our electronic engineer just walked in, radiation will excite an electron so if it was a really weak signal and you had a large radiation source it would create back ground noise.
    So in this case its unlikely but even if it did generate noise you could just switch it off measure the noise and filter it out.

    so yeas everything there is complete bollocks.

    Well spotted

  13. Re aircraft carriers I still don’t understand why we need the things at all. Anyone have a reasonable military explanation rather than the usual stuff about punching above our weight, place at world table and the like ?

    Tim adds: Basically, because aircraft carriers are what a Navy is these days. Without them you’re really a Coastguard.

  14. Tim adds: Basically, because aircraft carriers are what a Navy is these days. Without them you’re really a Coastguard.

    Really ? Where do submarines fit into that and are two carriers enough to make a navy, who are they to be used against and why, how much use is a navy in defending us these days and do we really need anything much more than a coastguard anyway ?

    Tim adds: !”Where do submarines fit into that” Subs protect carrier fleets.

    “are two carriers enough to make a navy”

    Yes, couldn’t have done Falklands, Sierra Leone, Liberia, without them.

    “how much use is a navy in defending us these days”

    Not a lot. A Navy is about power projection. Mebbe defence of the sea lanes.

    “do we really need anything much more than a coastguard anyway”

    Which is indeed the interesting question. Do you want a Navy or a Coastguard?

  15. I still don’t understand why the government didn’t just buy some American nuclear carriers instead of insisting on designing our own inferior ones. Why the hell aren’t they nuclear, for a start

    This is a major discussion in Australia at the moment, a country which has never been a military power but champs at the bit to serve its masters with glory.

    Half-sensible people say, “why don’t we lease our next generation of submarines from America, rather than spending fortunes on them here?”

    Deluded people say, “no, let’s build more expensive submarines here, so we can use them independently of America”.

    And sensible people say, “can we not just keep on sending a few poor sods to every stupid war of no relevance to us that America has, and assuming their blood will be repaid?”. Which would be appallingly and grossly cynical if the same bargain wasn’t also implicit in all of the other options.

  16. Meanwhile, a Britain with nuclear subs, two proper carriers, and proper airbases in Mount Pleasant, Ascension, Gibraltar and Cyprus is in the top 3 of best defended nations. Haven’t checked the rankings w.r.t France.

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