43 research outputs found
Supercritical water-cooled nuclear reactors: thermodynamic-cycles options
Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Currently there are a number of Generation IV
SuperCritical Water-cooled nuclear Reactor (SCWR)
concepts under development worldwide. The main objectives
for developing and utilizing SCWRs are: 1) Increase gross
thermal efficiency of current Nuclear Power Plants (NPPs)
from 33 – 35% to approximately 45 – 50%, and 2) Decrease
the capital and operational costs and, in doing so, decrease
electrical-energy costs (~$1000 US/kW or even less).
SCW NPPs will have much higher operating parameters
compared to current NPPs (i.e., pressures of about 25 MPa
and outlet temperatures up to 625°C). Additionally, SCWRs
will have a simplified flow circuit in which steam generators,
steam dryers, steam separators, etc. will be eliminated.
Furthermore, SCWRs operating at higher temperatures can
facilitate an economical co-generation of hydrogen through
thermo-chemical cycles (particularly, the copper-chlorine
cycle) or direct high-temperature electrolysis.
To decrease significantly the development costs of a
SCW NPP, to increase its reliability, and to achieve similar
high thermal efficiencies as the advanced fossil steam cycles
it should be determined whether SCW NPPs can be designed
with a steam-cycle arrangement that closely matches that of
mature SuperCritical (SC) fossil power plants (including their
SC turbine technology). The state-of-the-art SC steam cycles
in fossil power plants are designed with a single-steam reheat
and regenerative feedwater heating and reach thermal steamcycle
efficiencies up to 54% (i.e., net plant efficiencies of up
to 43% on a Higher Heating Value (HHV) Basis).
Therefore, simplified no-reheat, single-reheat, and
double-reheat cycles without heat regeneration and a singlereheat
cycle with heat regeneration based on the expected
steam parameters of future SCW NPPs were analyzed in
terms of their thermal efficiencies.
On this basis, several conceptual steam-cycle
arrangements of pressure-tube SCWRs, their corresponding
T–s diagrams and steam-cycle thermal efficiencies (based on
constant isentropic turbine and polytropic pump efficiencies)
are presented in this paper.vk201
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Objective Housing Sales and Rent Prices in Representative Household Surveys: Implications for Wealth, Inequality, Housing Market and Affordability Statistics
Many economic analyses require hypothetical but realistic sales and rent prices for properties representative for the housing stock and reflecting current market conditions. To achieve this, we replace subjectively reported prices in a representative household survey in Luxembourg by objectified hedonic imputations informed by observable market data. Thus, we propose a powerful tool for assessing the health and affordability of housing markets, compiling housing-related statistics and simulating hypothetical scenarios. This approach also enables us to test for the reliability of survey responses. When switching to
objectified values, we detect shifts in the wealth distribution, large regional variation in market indicators and striking affordability concerns: only 18% of Luxembourg’s renters could theoretically afford purchasing their inhabited dwelling given current market conditions. Further, participants’ tendency to mis-estimate market values strongly correlates with tenure length and type, dwelling type, income and wealth.FNR Luxembourg National Research Fund, CORE Grant No. 3886 (ASSESS
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OBJECTIVE HOUSING SALES AND RENT PRICES IN REPRESENTATIVE HOUSEHOLD SURVEYS: IMPLICATIONS FOR WEALTH, INEQUALITY, HOUSING MARKET, AND AFFORDABILITY STATISTICS
Publication status: PublishedMany economic analyses require hypothetical but realistic sales and rent prices for properties representative of the housing stock and reflecting current market conditions. To achieve this, we replace subjectively reported prices in a representative household survey in Luxembourg with objectified hedonic imputations informed by observable market data. Thus, we propose a powerful tool for assessing the health and affordability of housing markets, compiling housing‐related statistics and simulating hypothetical scenarios. This approach also enables us to test for the reliability of survey responses. When switching to objectified values, we detect shifts in the wealth distribution, large regional variation in market indicators, and striking affordability concerns: only 18 percent of Luxembourg's renters could theoretically afford to purchase their inhabited dwellings given current market conditions. Further, participants' tendency to mis‐estimate market values strongly correlates with tenure length and type, dwelling type, income, and wealth.FNR Luxembourg National Research Fund, CORE Grant No. 3886 (ASSESS