On Aug 20, 9:01 pm, T. Keating  wrote:
> On Tue, 19 Aug 2008 17:23:23 -0700 (PDT), deza...@usa.net wrote:
> >On Aug 19, 4:57 pm, T. Keating  wrote:
> >> On Tue, 19 Aug 2008 14:02:32 -0700 (PDT), deza...@usa.net wrote:
>
> >> FLiBE ... No such compound... doesn't exist in our universe. .
> >> Correct designation is  2LiF-BeF2. a mixture of two compounds. it was
> >> used as a secondary coolant.  
>
> >> The ORNL pyrolytic carbon moderated 7.4 MWt reactor was AIR cooled !!!
>
> >> The fuel used in MSRE was LiF-BeF2-ZrF4-UF4(*)  (a mixture of 4
> >> compounds.)
>
> >> (*) U233 isotope was used in UF4 mixture.
> >> The breeding blanket of Th232 was omitted in favor of neutron
> >> measurements.
>
> >Congratulations on finding the wikipedia page.
>
> >> Some obvious problems with the design..
>
> >> Difficult, if not impossible to scale up GWt output levels.  Large
> >> scale heat transfer (required for power generation) has a tendency to
> >> separate out mixtures.  This level of cooling often results in uneven
> >> mixtures and hot pockets. (Run-away chain reaction is a possibility.)
>
> >Do you just make this shit up? This wasn't reported by ORNL. You have
> >potential problems of noble metals plating on the heat exchangers, but
>
>  The 7.4MWt Reactor was AIR COOLED..  (Somewhat low thermal
> disapation/gradiant).
>
> There is a major issue when it comes to scaling up the design. How to
> move enough coolant through the core without pressurizing?   It's
> doubtful That one can cool the core @ 3GWt levels using gravity feed.
>   Simple physics, I suspect that  max flow rate will top out
> somewhere between ~5 to 15ft/sec.. Probably much lower..  )

You use molten salt cooling loops... Oh well, its obvious that power
systems engineering isn't your strong suit. Not that you need to build
any molten salt reactor anywhere as near as a typical LWR anyways, and
a 1 GWe LFTR would be 2GWt given the higher operating temperature, but
I digress.

> Limiting Delta T in the core to 50C. indicates that one needs to move
> ~14 tonns of fuel through the core and into the heat exchanger each
> second.   An even larger issue is scaling up of the heat exchangers.
> Similar problems with the secondary cooling system..

Really, you might want to bring this up with the engineers who
adressed these issues decades ago and tell them their analysis was
crap.

> >these are fission products and this poses a maintenance problem more
> >than anything else. The fissonables are highly soluable in the salt.
> >You dont even know what you mean by 'Run away chain reaction is a
> >possibility.' Its a meaningless statement. I assume you want to say a
> >criticality excursion is a possibility, but thats unsupported by the
> >strongly negative temperature and void coefficients of these types of
> >reactors.
>
> Anytime you mix compounds with differing melting points and thermal
> coefficients.. run through a heat exchanger a few millions of times,
> it will undergo separation.   The larger delta T the more separation.

Thats not a concern with FLiBe eutectics as was shown in the multi-
year operation of the MSBR at ORNL. Right now you're playing the anti-
nuclear activist that is grasping at straws. Stick to fearmongering,
it sells better and is more credible than trying to convince engineers
who know better.

> >> Used a Th layered blanket design, which will always have inherently
> >> LOW breeding ratio.  Lucky to achieve  0.2 breeding ratio, claims to
> >> otherwise not substantiated.  
>
> >Now I know you dont know what you're talking about. LWRs have breeding
> >ratios around .6
>
> Bzzzt.. more like "0.3", Heavy water designs have a somewhat higher
> breeding ratio but incur significant energy costs separating out
> replacement D from the environment.

http://en.wikipedia.org/wiki/Breeder_reactor
---
At a burnup of 30 gigawatt-days per metric ton of uranium (GWd/MTU),
about thirty percent of the total energy released comes from bred
plutonium. At 40 GWd/MTU, that percentage increases to about forty
percent. This corresponds to a breeding ratio for these reactors of
about 0.4 to 0.5. That is to say, about half of the fissile fuel in
these reactors is bred there.[6] Correspondingly, this effect extends
the cycle life for such fuels to sometimes nearly twice what it would
be otherwise. MOX fuel has a smaller breeding effect than U-235 fuel
and is thus more challenging and slightly less economic to use due to
a quicker drop off in reactivity through cycle life.

This is of interest largely because next-generation reactors such as
the European Pressurized Reactor, AP1000 and pebble bed reactor are
designed to achieve very high burnup. This directly translates to
higher breeding ratios. Current commercial power reactors have
achieved breeding ratios of roughly 0.55, and next-generation designs
like the AP1000 and EPR should have breeding ratios of 0.7 to 0.8,
meaning that they produce 70 to 80 percent as much fuel as they
consume, improving their fuel economy by roughly 15 percent compared
to current high-burnup reactors.
---

Where you would get the notion that a molten salt reactor would have a
breeding ratio lower than a LWR is a bit confusing to me, especially
when the salt has a neutron capture properties much lower than light
water.

> >> Claim of high burn up, contra indicated by extensive clean up
> >> procedures needed to decommission reactor after 40 years.
>
> >This has nothing to do with the burn up or even the reactor. Thats
> >radiolysis of the frozen salt when left unattended for years.
>
> The experiment did NOT breed U233..  
>    It was an experimental reactor that consumed U233 as a Fuel.

And that has nothing to do with the radiolysis of the frozen salts.
Where were you going with this?

>
> >We dont need LFTR tomarrow or at all. LWRs are more than sufficient
> >for several centuries. Perfecting LFTRs would be very desirable
>
> Bzzzt.. recoverable UO2 fuel will be gone by the end of this century..
>
>    After that.. it will cost wayyy more in energy/material
> expenditures to retrieve new U235 supplies than one receives back.
> Uranium mining is a function of chemical & material transport problem.
> Those inputs/energy requirements  increase significantly as the grade
> of ore drops.

It increases in inverse proportion to the ore grade agreed, and we can
analyze what that means at the end.

> >because it would make nuclear power production cheaper, more
> >efficient, and safer, but its certainly not staking the future of
> >humanity on a single energy supply.
>
> >Now I could make a similar argument:
>
> >Only the very FOOLISH propose that  humanity stake it's ENTIRE  future
> >energy supply on a renewable energy regime that's never been built,
> >nor tested. Even if you started today, a commercial renewable grid
> >wouldn't be viable for thirty, maybe forty years.
>
> Bullshit..
>
> Known mature technology based on renewables is being deployed on a
> large scale..  If the Sun ever stop's shinning the biosphere will be
> toast anyway.. (no food & heat.)

If you call non-hydro sources at less than 1% global energy production
large scale, sure.

> >> Meanwhile ..
> >>   Renewables are practical today...
>
> >In spite of wind powered Denmark having far higher electricity costs
> >than nuclear powered France
>
> The radioactive technology that France will be decommissioned in less
> then a century and replaced with renewables..  
>
> Oh.. and let's not forget that the French government operates the
> public utility, meanwhile Demark uses a free market system.
>
> http://www.energistyrelsen.dk/sw23521.asp
>
> Meanwhile,the French are providing massive subsidies to it's Nuclear
> industry..

And they still show far lower electricity costs at the end of the day.

> Lastly
>
> http://www.windpower.org/composite-1971.htm
> The Danes have built up it's wind turbine industry into a viable low
> pollution export sector.
>
> http://www.renewableenergyworld.com/rea/news/infocus/story?id=46749
> "Denmark to Increase Wind Power to 50% by 2025, Mostly Offshore"

And they sure thank the Swedes for the convenient dispatchable supply.
Though they wont be happy paying the natural gas bill or for all the
excess distribution infrastructure.

> >>   Pose no special environmental hazard.
>
> >Tell that to the victims of banqiao dam.
>
> A packed Soil dam built by the PLA (chinese army) using soviet
> engineers designed for a 1 in 1000  yr.. flood..    then 1 in 2000yr
> flood occurred in 1975 and over topped the dam.. it failed with
> predictable results.
>
> Did it contaminate the SOIL for a thousand years??  NO..
> Condemn generations of survivors to birth defects, and cancers?   NO..

And there hasn't been any statistical evidence Chernobyl has either.
You saw a sharp jump in thyroid cancers to those in the immediate
area, and then no statistically measureable epidemiological evidence
of your wonderful tale of woe. Now if you really want to stamp out
unnecissary cancers, campaign to prevent phosphate fertilizer in
tobacco or something else that actually has a statistically
significant effect. Sure, when you vaporize a gigawatt reactor in a
populated area you dont want to eat the dirt, but I wouldn't want to
do that around any chemical plant that deals in toxic material that
are required for various renewable technolgies either.

To suggest that renewable technologies are without risk is to simply
ignore the evidence.

> >>   Are subject of a near continuous stream of incremental improvements.
>
> >Just like nuclear energy, imagine that.
>
> Not really.. Despite massive subsidies,
>     Reactor improvements have ground to a halt..
>         I.E.  Beating a dead horse !!!.

AP1000 and EPR and PBMR not withstanding.

> >>   Derives energy from a nearly inexhaustible source,  which will
> >> likely outlast mankind and every other species on Earth.  - Hide quoted text -
>
> >Where using the 160 trillion tonnes of fissionables would only last
> >humanity 16 million years if you burn it at 1000 times our global
> >energy consumption....
>
> Bzzzzt..  Why in the world  would one propose dependency on fuel
> source that requires mining all the Earth's surface?   You'll run out
> of energy and materials longgggg before  you achieve your goal..
>
> (P.S. Negative EROEI.. after concentrations drop below 100-200 PPM U.)- Hide quoted text -

Well, this is my favorite part of what is obviously, measurably wrong
from basic measurements from Rossing mine:

http://nuclearinfo.net/Nuclearpower/WebHomeEnergyLifecycleOfNuclear_Power

---
Another Uranium source for Forsmark is the Rossing Mine in Namibia. A
description of the operations of the mine is available here. The
Rossing mine produced 3037 tonnes of Uranium in 2004, which is
sufficient for 15 GigaWatt-years of electricity with current reactors.
The energy used to mine and mill this Uranium was about 3% of a
GigaWatt-year. Thus the energy produced is about 500 times more than
the energy required to operate the mine.
---

Rossing mine is at 300ppm. So the energy return on mining drops from
500 to below 1 with an ore grade of 1/3rd as rich as Rossing?