Ofc modern reactors can run for years without Xenon poisoning.
Silly!

You have the reading comprehension of used wad of chewing gum.

The Xenon poisoning happens when you _shut it down_ or _power it down_ to a lower power output level.

Absolutely incorrect - xenon accumulates in the reactor (to a level determined by a variety of complex factors) and poisons the reaction even during steady state operations, and this must be accounted for in the design of the reactor. (As I said, for an example of this, look up the first run of the Hanford plutonium production reactors - which were completely shut down by xenon poisoning.) Xenon does not magically appear or magically start absorbing neutrons just because power has been reduced or the reactor has been shut down.
 

This happens with _all_ reactors currently in use.

I never claimed that xenon did not accumulate in all reactors currently in use - I merely pointed out that the behavior of civilian reactors with regards to xenon poisoning is the result of a deliberate design choice and operating philosophies, not a law of nature. Again, consider the difference in behavior between the first run of the Hanford plants and a modern plant.
 

I understand very well about what I talk. After all I work in that area since decades.

No, you very obviously do not know what you're talking about.

I don't see how these delayed neutrons can be responsible for the majority of the 7% decay heat.

It doesn't all come from delayed neutrons. It's a combination of delayed neutrons, fissions due to the delayed neutrons, and decay of the daughter products. It's both in what I wrote and the Wikipedia article on decay heat which I linked to.

You are wrong about the design choice.

[[Citation Needed]].
 

I suggest to google

You rely on Google. I'll rely on actual experience with nuclear power plants and decades of research.
 

There is no design that avoids having decay products like Xenon that prevent you from holding down the reactor in the wrong tome window. Sorry that is a /. myth. Even if it was true it would not matter, as we are talking about current reactors and why the current ones either have to power up quickly or have to wait a few hours to do so.

Google the operating history of Hanford plutonium production reactors - which were completely shut down by xenon poisoning when they were first started. Then consider modern civilian reactors - which can run for months or years without being shut down by xenon poisoning.

And then kindly fuck off. Because you have no clue what you're talking about - you're a parrot mouthing words you do not understand.

Every few years we read about long lost civilizations that were found by aerial footage. I remember a handfull of years ago people were using google earth to locate some. Its always interesting when the news comes out. but 99% of the time once its "found" thats the end of it for us, no more news ever comes out.

Plenty of news comes out - if you're following the relevant news sources. If you rely on mass/popular media (which relies on sex and shock to sell, and includes Slashdot), all you're going to get is sizzle - the steak is in the specialized news.

I wonder how many TV companies would shovel over billions for the rights to broadcast "The Real World"/"Survivor"/"Big Brother" Mars for long term funding.

Pretty much none I suspect. The show would have to be a top hit, year after year, in multiple large markets to even come close to paying for the costs of the mission. The major American networks pay, collectively, 3.1 billion per annum to the NFL for broadcast rights - and the NFL has a *HUGE* built in audience. (Averaging 22 million per game - the last season of Big Brother in the US averaged about 6 million per episode.) On top of that, the big drama draws (voting someone off the island/evicting them from the house, alliances, etc..) of such shows are essentially impossible for Mars One.

What you write is complete nonsense.

There is no 'neutron capture' taking 15 minutes.
Either it smashes an uranium atom, that is called fission, or it is captured by boron ...

Not entirely nonsense, he just gets the mechanism wrong - what's actually delayed is neutron release.
 
 

That means, the decaying products of the fission reaction produce so much Xenon and Boron that the neutrons of an start attempt get captured by them. Hence a new 'controlled' fission reaction is not possible, until those elements decay further.

That takes hours, up to days. This is the main reason why nuclear plants can only be used very limited for load following (if you power it down considerably, you have to make sure you either don't need it full powered soon, or you know you will power it back up VERY soon)

You're correct in your assertion that daughter products can inhibit or delay reactor restart - but you're incorrect in asserting this is why nuclear power plants can't be used except for minimal load following. That's a design choice, not a law of nature. Civilian power plants are can't be used for load following because they're designed to run under more-or-less steady state conditions for safety and economic reasons. Naval power plants on the other hand are designed to operate as load followers because of the need to respond quickly to throttle commands and other demands on the plant. Even though they work on the same physical principles, the detailed engineering is different.

"Normally there is some time between neutron capture and actual nuclear fission (I have heard a figure of 15 minutes)."

The fact that you can detonate a nuclear bomb by bringing together two subcritical pieces of U-235 shows that this can't be true.

Actually, the grandparent is partially correct - he's describing what is called slow fission, and it's what makes fission reactors practical. Though to be fair, you're partially correct as well - you're describing fast fission (prompt criticality) which is what makes nuclear bombs possible. The difference between the two lies in the engineering, I.E. the presence of a moderator, the amount and type of nuclear materiel present, etc..., etc...
 
What makes you both partially correct is that there isn't a delay in fission, but a delay in neutron release.
 
  Decay heat in reactors comes partially from these delayed neutrons, partially from the fission of daughter products. (Right after shutdown, the former predominates, over time they cross over until the latter predominates.)
 

In a nuclear reactor, 7% of the heat output is from the decay of the fission products (alpha and beta decay). This 7% will continue to be generated regardless of control rods or neutron absorbers.

No. Under normal operating conditions, about 7% comes from various delayed sources - but when the reactor is shut down, the neutrons creating those sources are essentially shut down as well. Thus, over time the amount of energy released from those sources falls off over time (reaching .02% of normal operating power within a week) as the delayed neutrons are exhausted and short half life fission products decay.

Precisely this - and then he went one step beyond with a carefully tailored PR campaign to the public the impression that *he* is the expert on all these things.

So probably the book will be ghostwritten.

The ironic thing is that this setup has been in place for at least seven years, and is still working without issue. Otherwise, I'd definitely be made aware that it was not working.

You can't draw a curve through a single point.
 

I'll turn the question around... why does a device have to be onto the Internet if it doesn't have to?

Well, the "doesn't have to" represent an assumption on your part. For a lot of things, it's awfully dang convenient, reduces or eliminates, human error, and saves a ton of man-hours.

No, this system wasn't fast, but while it did the job it was a bit of a lashup that required extra coding, installation, and maintenance where info could be read but a blackhat couldn't tamper with the isolated network without physical access.

TFTFY.

The parts you left out are why you don't grasp why the devices are on the internet.

That's one thing I've always been mystified at --- when the English Channel tunnel was finished the machines were run a bit further and entombed --- why weren't they run up to the surface and put up for use on other projects?

Because machine lines the tunnel behind it as it drills and moves forward, and because construction continues behind it... meaning they couldn't be "just run forward" as the tunnel ahead was larger than the machine. So they either have to be entombed (as the British did) or dismantled and scrapped (as the French did). Most large TBM's are also custom built, so there's little resale or reuse value to begin with.

Which is why it's always a good idea to read the summary

The problem isn't that I failed to read the summary, it's that you failed to comprehend the summary.
 

Camera is primary system of notification. If he notices the wife flailing about, he can call appropriate people. If he doesn't notice because he's otherwise occupied, the child is a back-up.

A camera is a method of monitoring - it is not a system for providing notification. These are two very different functions. (Something I would have thought Slashdot would grasp intuitively.)
 

Reading: It's FUNdamental.

It is, you should try it sometime.

Yeah, except all he's *really* asking for here is an additional way to get notified if something's wrong, so he could take a look for himself via an internet connected camera.

The way I'm reading this, he just wants an extra fail-safe in place.

Since he didn't specify the existence of a primary method of notification... it's an assumption that he's looking for an additional or extra method of notification.

You're asking for a kind of button that will make it possible to rely upon a 2-year-old child as a caretaker.

That's funny. I thought he was asking for a kind of button that would make it possible for his child to communicate with him as a backup measure, given the video surveillance and all.

Well, you thought wrong - because he plainly states the purpose is to have the two year old alert him that he needs to check the video cameras and there is no indication of either the existence of a primary alert system or that he is monitoring the cameras with sufficient regularity to serve as the primary alert system.
 

You're also free to argue that epileptic parents should not be allowed to be alone with their children since their children might be required to be "caretakers," whether via a button, a telephone capable of 911, or merely living within distance to run to a neighbor. Because we'd all support that.

"Child", not "children" - and really, a toddler, not even a child. (The infant can safely be left out of the "caretaker" equation.)
 

This is an attempt to shift all responsibility for the parent's care onto the child.

It's an attempt to shift a significant portion of the care onto the toddler. Anyone with sense would question that.

Dammit! Beat me to it.