Re: Arado 234 with liquid hydrogen engines? - SS hiding one in woods

On Jul 17, 3:34 am, "Keith Willshaw"
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On Jul 16, 4:12 am, "Keith Willshaw"





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Several long objects of differing designs do not amount to control rods.
Heisenberg is on record as stating there were none. Those are neutron
probes,
Nope "control rods" see page 10 of this link.
http://www.en-genius.net/includes/files/col_050409.pdf

Its simply wrong. Irving had the right of it as Heisenberg confirmed
in both his debriefings by the Alsos team and his interview
with Professor Joseph Ermenc ofDartmouth College at Urfeld in
August 1967.
Nothing of the sort was said at all.
Not in Irvings book, not in the Joseph Ermenc interview you post.
Irvings book does talk about 'lumps of cadmium' but then the term
"lump of cadmium" to be used in the remote possibillity of criticality
doesn't preclude manualy inserted "control rods" to be inserted to
test their effect on the neutron multiplication coefficient.   The

Irving's book says it clearly and explicitly on page 358

<Quote>
Distinction must be drawn, however, between the German
achievement in the theoretical field, as stressed by the report
discussed above, and the work on uranium reactor technology.

In the latter, they were backward to an alarming degree, and the
lack of provision of control and regulating mechanisms in their
various piles, and the lack of adequate instrumentation, has already
been commented upon. The theory of cadmium-sheathed
control rods was given not even a cursory numerical treatment.

There was not even some simple provision for draining the
heavy water quickly through an outlet in the bottom of the vessel,
should the reaction have got out of hand. Had the Haigerloch
pile reached criticality,* the Germans would have encountered
the same unexpected difficulty in shutting it down as did
the Americans when their heavy-water pile first went critical in
the middle of 1944. Nor had the Germans realized the importance
of delayed neutrons as the factor in controlling atomic piles
</Quote>

I cant see how you can be clearer than that and Heisenberg
described the book as technically accurate

The thing to note, as always, is that Haigerloch was meant to be
'subcritical' ie short of a sutained chain reaction.

It can't be judged by the same standards as a reactor would be since
it wasn't a critical reactor.

Note that the Germans knew how to calculate criticality and pile size:
from Irvings Virus House:

The most remarkable verdict on the German work on uranium
piles was passed in a secret report written by two Oak
Ridge scientists* for Dr. A. H. Compton in November .
Shortly before, the question had arisen of the advisability of
publishing the very comprehensive American Plutonium Project
Report. Compton was advised that expert analysis of the German
Kernphysikalische Forschungsberichte  the Nuclear Physics
Research Reports circulated by Schumann, Esau and Gerlach 
showed that the publication of the American volumes would reveal
few secrets not already unraveled by the Germans.
The two scientists posed and answered a number of questions.
Did the Germans know the correct lattice dimensions for a
heavy-water/uranium system? “The answer is an unequivocal
yes.” In December , Bothe and Fünfer had reported on their
experiments on various lattice arrangements measuring the
strength of a neutron source with and without the uranium lattice
in place; the Germans’ main conclusion had been that “a
combination of  centimeters of heavy water and one centimeter
of uranium metal, density , is the most favorable.” The
American physicists remarked: “This conclusion is exactly the
same as that reached by us on the basis of calculations in August
 (CP-).” So the German work had been performed, they
said, at the same time as theirs









links I provided shows that at least 3 physicists had envisaged the
use of cadmium control rods for use in regulating a future possible
fully critical power reactor.

Indeed but this was not that future reactor

Indeed, but it was not to be critical it was their penultimate
experiment before the real critical reactor. This was probaly the
8th such 'pile' with the preceding ones having verified and expanded
their understanding.

It was von Weiszaker who in 1934 suggested that Cadmium be used to
regulate the power levels of a reactor. He suggested cadmium solution
in the heavy water: something that would required continious
distilation to keep a reserve of concentrate and pure water for
adjusting solution strength.

"The problem was that this enormous energy would be unleashed
within one hundredth of a second: was there some
means of controlling the reaction, of taming it for peaceful purposes?
He thought it would be possible to stabilize the reaction in
some future “uranium engine” by adding cadmium salts to the
water used to absorb the neutrons’ energy inside the machines.
Cadmium was a very strong absorber of neutrons, and could be
used to shut the machine down altogether if things threatened
to get out of hand. It was this article, coupled with an article he
wrote for the German national newspaper Deutsche Allgemeine
Zeitung in the middle of August, that quickened the interest of
the German authorities in nuclear research."

Diebners reactors had Cadmium plates for regulation.



I've also provided two links, one with
photographs of the museum exhibit of the control rods.  There are no
conncectos for probes on those rods.

There are no neutron measuring devices or real uranium cubes either.
This is after all a reconstruction. The original material was mostly
removed before the Americans got there. We do know however
that the germans used neutron probes

The Americans destroyed the cellar, and unfortunatly much of their
documents have been lost.

We do know that the German physicists anticipated control by cadmium
from the very begining of 'their' discovery. (page 34 virus house)
and Diebner had cadmium plates for his reactors.

Their one omision was the fact they didn't take into account time
retarded decay/fissioning. This adds a 1st order lag and delays
buildup (and decay) and in fact makes the nuclear process EASIER to
control than they themselves anticipated. Exploitation of these lags
would have been perceived as testing of B8 continued.




Secondly Heisenberg says that 99% of Irvings facts are correct.
Notice he didn't say 100%?   When someone says 99% correct he doesn't
mean 100% correct or even 99%, he means substantially correct.

Just so, dont you think if he had control rods he would have regarded
that as a sustantial error. In fact the reason Heisenberg held back the
1% was not because of factual or technical errors but as he clearly says

<Quote>
I think that Irving's book is a very good book in
the facts.  But it has one deficiency.
When he tries to determine motives he does not do very
well because he can not really think himself into the atmosphere of a
totalitarian country making war
</Quote>

Wriggle as much as you like Heisenberg had no complaints about the
facts in the book.

Wiggle as much as you like: Heisenberg says the "facts" are very good
but he doesn't say perfect. Cadmium control was forseen from the
very begining and admium plate control rods were available in the 1942
experiements.

He says it has a defiencieny when Irving tries to intimate the motives
of people.


In fact given the German physicists desire to use cadmium stemming
from pre war days its not suprising they would include cadmium tipped
probes to measure their effect for inclusion in some future critical
reactor.

What was missing on the B8 was automatic regulatin mechanisms: but
then it was not to need them as it was subcritical.


Due to the situation at the end of the war the B8 'reactor' was
severly compromised: it was to have used rod shaped fuel elements, it
was to have an more elaborate control rod setup.

I know it was compromised, I have been saying so.

It was criticised unchasitably by detractors of Heisenberg and the
German physicists, those who wanted to pariahtise them , who used the
fact that the B8 lack of automatic control rods with lack of any kind
of manual (cadmium) control rod on what was afterall a subcritical
experiment.

They BELIEVED it would not go critical but they didnt know.
Not taking the relatively simple precaution of having Cadmium
control rods available was IMHO reckless. Taking chances
on criticallity experiments is dumb and has killed people.


People got killed in the US program, they didn't in the Germany,

No one in Germany too the risks that happened in america when enriched
uranium was brought in contact.



In part this comes from Heisenbergs correct assumption that a reactor
could be self regulating.   This is because as temperatures increase
U238s doppler absorbtion band broadens and it becomes more likley to
absorb a neutron and not fission thereby preventing that neutron from
absorbing into fissionable U235.   The revolutionary German pebble
based reactors with their ceramic fuel elements were able to be
intrinsically safe.

Oh please spare me the lectures on reactor physics. A negative power
coefficient is something most commercial reactors have, the Soviet
RBMK didnt and we all know where that went. This doesnt mean
an uncooled reactor is safe, see 3 Mile Island.

You need lectures.

The negative feeback provided by doppler broadening as temperature
increases is significant in a high temperature pebble reactor because
of the higher opperating temperature and the abillity of the fuel
elements to take those high heats and the abillity of the reactor to
cool itself passively. Shutdown the pumps on a current reactors and
the reactor is seriously damaged. Nothing happens in a pebble
reactor.



Heisenber initially overestimated the effect but
had realised the effect became effective over 1000C not a few hundred.

?

FFS, Heisenberg realised that at the temperatures in question
doppler broadening was inadaquete on its own.



B8 was well shielded on 5 of the 6 sides, anyone who stood above the
reactor, with the neutron source present and armed (radium insered
into the berylium) was exposing themselves since there was only about
50cm of shielding.

Which was rather my point

Could be dealt with proceduraly/.


 So long as they removed the neutron source before
adjusting the probes and so long as the adjusted them by lanyard etc
they could so so safely but yes the safety features were compromised.

Wrong, once the reaction starts you can pull the source all the
way out and it will continue.


But it wasn't critical.


The thing is now making its own neutrons,
thats what a chain reaction means after all. The only way to shut it down is
remove
the moderator, fuel or insert control rods. BTW you really dont want
to stand over the hole in the top of a reactor thats running away.
Its bad for your health :)


It wasn't critical and their calculations were correct.


<snip>

Heisenberg doesn't deny the control rods.  He merely says Iving is
"99%" correct on facts.

Indeed and control rods are a biggie. NOWHERE does Heisenberg ever
mention the Haigerloch reactor having control rods even though it
was a major criticism that it didnt.

It didn't have automatic control rods, cadmium could could be inseted
manually, not as a safety precautions but as a experimental system.





.

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