Re: Uranium availability


"T. Keating" <tkusenet@xxxxxxxxxxx> wrote in message news:7hr763h36i2g15f64q0hi2re9m9s70guv0@xxxxxxxxxx
On Sun, 3 Jun 2007 12:04:27 -0400, "daestrom"
<daestrom@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:


"T. Keating" <tkusenet@xxxxxxxxxxx> wrote in message
news:75fr53hb2k6c9jofvnfcss7h6lqi4rmim5@xxxxxxxxxx
On 30 May 2007 08:22:12 -0700, bill <ford_prefect42@xxxxxxxxxxx>
wrote:
<snip>

In a different thread, it is estimated that uranium extraction
should be possible from sea water and coal ash at roughly $200/kg.
assuming that number is off by a full order of magnitude, and it will
really cost $2000/kg, that still only represents
3 500 000 kwh/kg / $2000/gk = $.0005/kwh in fuel costs assuming
reprocessing.

You're off by a factor of 118x.

Maximum current yield is ~35,000 kWh per kg..

Assumptions.

1GWe/3GWt reactor.
220,000 kg of U consumed per annual refueling cycle. (includes
enrichment consumption.)
90% duty factor.
95% actual production factor.
$2000 per Kg of U.

Math

1GWe * prod-f(.95) *.duty cycle (.90 )/1000 /hr = 855,000kWh/hr
Est annual production 855,000kWh*365*24 = 7.49 GWh/yr.
7.49GWh/yr / ~220,000 kg of raw U consumed == 34,045 kWh/kg.


You seem to be 'double-dipping'. What exactly is a 'duty factor' and how
does it differ from an 'actual production factor'?? Making up your own
terms to sound knowledgeable in commercial power production?

Duty Factor, downtime for annual refueling(2>wks), inspection,
maintenance, and other scrams.

Not even close. Good plants run 25 days every two years (12.5 days / year) for refueling. Unplanned scrams average < 0.4 scrams per two-year fuel cycle.


Production factor..
Deration factor for elevated temps,internal power consumption, and
load management(turbine bypass).

LOL. "load management(turbine bypass)"?? You read that in some 40 year-old textbook on nuclear power, didn't you? Any idea how modern US nucs are loaded?? What fool of an operator would keep reactor power high and reduce turbine load, necessitating turbine bypass?? For many plants, using the bypass valves while the turbine is on-line is strictly forbidden by their license. Bet you haven't a clue as to why. (I'll give you a hint, ever heard the term 'anticipatory scram signal' ??)

If enough nucs are available that some actually need to start 'load-following', then the calculation for 'capacity factor' has to be updated to match that used for other 'load-following' units. But trying to apply 'capacity factor' to a unit that is deliberately unloaded to meet ISO demands is ridiculous and meaningless. And since reactor power follows in 'load-following' mode, the consumption of uranium does also.

Both of your made up terms are *included* in the overall 'plant capacity factor'. That is why NEI uses 'plant capacity factor' averaged over a complete fuel-cycle (including the 20-30 day refueling outage) and all forced, scheduled and unscheduled outages. It gives a much simpler, all-inclusive measure of plant performance without all your 'hand-waving' made up terminology.

Care to explain how the 'plant capacity factor' for the median US nuc is so much higher then your made up terminology?? If a plant's capacity factor for a two year run of the median plant is 93%, how can it's duty-factor*production-factor be only .855 ??


Notes: N plant is significant;y less efficient during summertime
temps. Slow Thermal response time & Mechanical stress reduction
techniques dictates increased use of turbine steam bypass as
percentage of overall Npower production increases.


BULL. You obviously have no idea how a commercial nuclear plant is run. Turbine steam bypass is *not* used for anything except startup before the turbine casing has been warmed. "Slow thermal response time" is another piece of BULL. Nuc plants as a rule don't load-follow. In a few countries they do, but the economics of nuclear make it a bad idea. There are two limits to nuc plant power rate-of-change, fuel conditioning and the steam turbine. The steam turbine of a nuc is no more limiting (in fact, less limiting) then a modern coal plant. Fuel conditioning, once performed (about six hours every other month) allows reactor power to be ramped at very respectable rates. About the only types of plants that can ramp power at higher rates are hydro and gas-turbine.

You're demonstrating your ignorance by opening your mouth.

Once the fuel in an LWR has been pre-conditioned and the turbine casing operated above 25% for a few hours, do you have any idea how fast power in a typical LWR can be ramped up/down? No, I didn't think so. You might find it hard to believe, but 2% / minute is not at all unusual. Mostly limited by the grid operator's demand and the reactor operator's 'comfort zone'. The only part of the plant subjected to thermal stresses from power changes are the steam turbines.


'Plant capacity factor' is the term used by the industry (and government) to
measure a plant's productivity. It includes *all* down time, whether
'scheduled' or 'unscheduled', whether 'forced' or 'planned' (yes, those four
terms have specific definitions). The capacity factor of a well run nuclear
plant over a two year cycle is in the low to mid 90% range. That includes
all maintenance and refueling down time. The net capacity factor for *all*
US nuclear plants in 2006 was 89.9%. Quite a bit higher then your 'duty
factor * actual production factor' nonsense. Over 1/2 of all US nuclear

As stated above ...
Consumption of energy inside power plants is significant..
Increased use of steam bypass.

As rebutted above. Plants do *not* use 'steam bypass' when/if they want to reduce power output. They simply reduce reactor power. The reactor power can be reduced much faster then you seem to think. The heatup/cooldown rate of large-steam turbines is more limiting then the reactor. But even those, once properly warmed can handle respectable rates of power level change. Well able to keep up with hourly load scheduling changes.

For those units (overseas) that *do* perform load-following, they do it by changing reactor power, not bypassing steam. BWR's use a technique of varying reactor core flow to vary reactor power. The turbine output in a BWR is slaved to follow reactor power and maintain reactor pressure constant. In PWR designs, load following is accomplished by directly controlling steam flow to the turbine. Reactor physics and an automatic rod-control system ensure that reactor power follows the demands of the turbine. In both cases, turbine steam bypass is *not* used during any phase of electric power production.



plants had a three-year rolling average capacity factor of 92.4%
http://www.nei.org/index.asp?catnum=2&catid=95
http://www.nei.org/documents/U.S._Nuclear_Industry_Capacity_Factors_by_Quartile.pdf

The production of your posited 1 GWe plant would be 1 GWe * 92.4% / 1000 /
hr = 924,000 kWh/hr. Not a huge difference (about 8% higher production),
but you really should try to be more accurate in your condemnation of
nuclear.

Your assumption that production variables will remain fixed.
Those are invalid assumptions..

No, my assumptions were *your* assumptions with a correction in one term. If you now are saying your own assumptions are invalid, well you've no one to blame but yourself.


As GW progresses per unit N power output will decrease.

????

Efficiency decrease also occurs when N-plants are used in demand load
conditions. (non base load).

Not because of any arcane idea about using turbine steam bypass that you seem to have.

If/when we have enough nucs that load-following becomes a concern, there are some modular designs that can be used. By shutting down individual 'units' the stations overall efficiency can be maintained at partial loads (because other 'units' will be running near optimum).

Even without that, since reactor power is reduced when 'load-following', the uranium consumption follows pretty close to MWhr generated. This is owing to not bothering with 'turbine bypass', but rather actually controlling reactor power.

Lastly, not all N plants are run as efficiently as those in the US.

That's true. Many run better. Ask France.

daestrom


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