Thursday, January 17, 2008

Materials cost revisited

Kirk Sorensen has called attention to a paper by Per F. Peterson and Haihua Zhao, "Material Input for Advanced Brayton Cycle Power Conversion Systems."

From the introduction:
• Two of the four major requirements for Generation IV reactor
systems (Gen IV) and the Next Generation Nuclear Plant
(NGNP) are sustainability and economics.
• The evaluation of construction material inputs is key to life-cycle
assessments for environmental impacts, and can provide a useful,
if only qualitative, plausibility check for economics claims.
• In nuclear energy systems, the major construction inputs are
steel and concrete, which comprise over 95% of the material
energy inputs.
• This study explores how the transition to high-temperature
closed gas power cycles affects these inputs.

On concrete:
Concrete amount plays a very important role in deciding the plant
overall cost:
»Concrete related material and construction cost is important in
total cost ( ~25% of total plant cost for 1970’s PWRs*)
»Concrete volume affects construction time
»Rebar in reinforced concrete is a large percentage of total steel
• about 0.07 MT rebar per MT reinforced concrete for 1970’s PWRs*
• Rebar is about 35% of total steel for 1970’s PWRs*
»Concrete volume affects decommissioning cost.

Resource inputs will affect future capital costs and
• Nuclear: 1970’s vintage PWR, 90% capacity factor, 60 year life[1]
–40 MT steel / MW(average)
–190 m3concrete / MW(average)
• Wind: 1990’s vintage, 6.4 m/s average wind speed, 25% capacity
factor, 15 year life [2]
–460 MT steel / MW (average)
–870 m3concrete / MW(average)

• the Gen III+ ALWR estimated to
have the lowest inputs, the 1380
MW(peak) General Electric
ESBWR, are 80 m3/MW(ave)
concrete and 32 MT/MW(ave)

Molten Salt Coolant Gas Cycle (MCGC) for VHTR and
design has almost a factor of two
reduction in specific steel inputs (3.7
MT/MWe(ave)), compared to the
GT-MHR PCU design.
• This is in part because
–it can be optimized at higher
operating pressures,
–and because the additional reheat
stages give a 5 to 10 % increase in the
cycle thermodynamic efficiency for
the same turbine inlet temperature.
• Coupled to a heat source such as the
Advanced High Temperature
Reactor (AHTR)*or the Advanced
Molten Salt Reactor (AMSR),
significant reductions in total metal
inputs appear possible.
Hot and cold leg configurations
for the MCGC based with three
(HP, MP, and LP) PCU’s and a
separate recuperator vessel (R).

• With similar power output, the
MCGC system is more compact,
and thus provides the potential
for major reductions in the
turbine building volume, and
power conversion system capital
cost, for future high-
temperature nuclear energy
systems, both fission and fusion.

From Reuters today:

The expectations in the market point to a 30 percent rise in the price of iron ore, a key raw material used to make steel, while industry sources in Australia have said Vale has offered an increase of 70 percent over current term prices.
"Those steel companies that are not self-sufficient in terms of raw materials will be seeking out raw materials-related companies," said Robert Miller, senior managing director of leading investment bank Miller Mathis, which advises the steel industry.
"There are a handful of major steel companies that are at or near self-sufficiency of raw materials but there are many that are still dependent on world markets," Miller said.

From The Houston Chronical yesterday:

[Aldo] Mazzaferro kept his "Attractive" rating on the sector and forecast for the metal as high as $595 per net ton in the second quarter of 2008. Steel cost $512 per net ton in the third quarter of 2007, according to his client note.

A note on material use in solar arrays: Yesterday I pointed to a paper by
Vasilis M. Fthenakis and Hyung Chul Kim, which stated that steel use is PV arrays ran from 3 to 10 times the steel use in Power Reactors. This would suggest a Syeel input of from 120 MT to 400 MT per MW of generating capacity. Steel use would be predominately for supporting. Concrete requirements for solar arrays would appear to be significant less that for reactors. However, the cost of other materials might significantly effect the cost of building solar arrays. For example, each electricity production unit has to be wired t0 a central point. For generating facilities covering hundreds and even thousands of square miles, the connecting wiring becomes itself a considerable expense.

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