[ARC5] ARC5 Digest, Vol 106, Issue 52

[Darryl Sage]

Hi will you please repeat that  hi  hi  73       darryl    ve3cpo

On Sat, Nov 10, 2012 at 12:00 PM, <arc5-request at mailman.qth.net> wrote:

> Send ARC5 mailing list submissions to
>         arc5 at mailman.qth.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://mailman.qth.net/mailman/listinfo/arc5
> or, via email, send a message with subject or body 'help' to
>         arc5-request at mailman.qth.net
>
> You can reach the person managing the list at
>         arc5-owner at mailman.qth.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of ARC5 digest..."
>
>
> Today's Topics:
>
>    1. Re: OD3 VR Tube - Not At All Like A Nuclear Reactor (J. Forster)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 9 Nov 2012 16:34:24 -0800 (PST)
> From: "J. Forster" <jfor at quikus.com>
> Subject: Re: [ARC5] OD3 VR Tube - Not At All Like A Nuclear Reactor
> To: "Mike Morrow" <kk5f at arrl.net>
> Cc: arc5 at mailman.qth.net
> Message-ID: <51482.12.6.201.2.1352507664.squirrel at popaccts.quikus.com>
> Content-Type: text/plain;charset=iso-8859-1
>
> My point was that a reactor is balanced between a growing and dying
> exponential. Not the details of how that is implemented.
>
> -John
>
> ===============
>
>
>
> > John wrote:
> >
> >> The math is very similar to a nuclear chain reaction, where a reactor is
> >> balanced on a knife edge between running away and shutting down. Control
> >> rods adjust the 'loop gain' of the reactor to exactly 1. Reactors do not
> >> work w/o active control.
> >
> > Well, er...nuclear reactors do in fact *often* operate without active
> > controls
> > of the type you imply.  Especially naval propulsion pressurized water
> > reactors.
> > For those, the operator's opening of throttles to a steam turbine
> > increases
> > the heat demand on the steam generator, which lowers the temperature of
> > the water coming out of the primary side of the steam generator that
> > then goes into the reactor core.  This lower temperature water is denser,
> > which moderates or slows down neutrons to the point that more nuclear
> > reactions occur as a result, which increases reactor fission thermal
> power
> > generation, which raises the temperature of the water coming out of the
> > reactor that is going back to the steam generator, to the point where
> > in a matter of about a minute or so the thermal power generated by the
> > nuclear core has matched the increased thermal power demand that was
> > caused when the operator opened the throttles to the turbine.  Everything
> > then stabilizes.  Had the throttles to the turbine been closed, the
> > response would be identical, but in the opposite direction of parameter
> > change.  This response is automatic and controlled by the physics of
> > the process, not by **any** external automatic human-designed control
> > loop.  It's rather beautiful to watch, especially when one understands
> > what is taking place!
> >
> > Plus...it's all rather slow and easily controlled, once again, by the
> > physics
> > of the process, not by a man-made external control system.  About 94
> > percent
> > of the neutrons that initiate one fission process cycle were generated
> > "prompt" one-hundredth of one-trillionth of a second earlier.  But the
> > other
> > 6 percent of neutrons taking part in one fission process cycle come from
> > neutrons generated by the decay of radioactive products of fission cycles
> > that occurred as long as several **minutes** earlier.  It's the effects
> of
> > these "delayed" neutrons that control the rate at which the fission
> cycles
> > take place, to the point that slow-moving control rods or thermal changes
> > as described above or any other man- or physics-made effect will very
> > easily control the fission and thermal power generation process.  There's
> > no "knife edge" anywhere in the process!
> >
> > Commercial pressurized water reactors and boiling water reactors are
> > not quite as simple in practice as the naval reactors, but are still
> > fundamentally similar.  I spent thousands of hours at the controls
> > of naval propulsion reactors and commercial boiling water reactors in
> > the past 38 years, before retiring.
> >
> > Returning to the subject of gas ionization avalanche, that is somewhat
> > analogous in nuclear fission terminology to a reactor operating from
> > one fission cycle to the next on prompt neutrons only.  That's called
> > a nuclear weapon...not a nuclear reactor!!
> >
> > 73,
> > Mike / KK5F
> > Former Senior Reactor Operator
> > ______________________________________________________________
> > ARC5 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/arc5
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:ARC5 at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> >
>
>
>
>
> ------------------------------
>
> _______________________________________________
> ARC5 mailing list
> ARC5 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/arc5
>
>
> End of ARC5 Digest, Vol 106, Issue 52
> *************************************
>