Difference between revisions of "Ship-based single-SMR"

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For smaller cities, with populations from around 130,000 up to 0 a design with twin SMRs offers better turn-down of heat during periods of lower heat demand i.e. late spring through summer into early Autumn.
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For smaller cities with populations from around 130,000 up to 400,000 a ship with a single SMR is deployed.
  
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One SMR is configured exactly as it would for the smaller single-SMR ship design, that is it operates year round in CHP mode producing electricity via a '''non-condensing''' turbine and using the low pressure exhaust steam to heat a district-heating water circuit. Any surplus heat in the form of uncondensed steam is removed by the on-board supplementary condensers and the cooling circuit for these is cooled, in turn, by water drawn from the estuary.
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[[File:SS SMR1.png|800px|frameless|left]]<br style="clear:both;" />
  
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The second SMR by contrast is provided with a second steam turbine of the '''condensing''' type which allows greater steam expansion within the turbine producing higher efficiency and electricity output. It is used at times when the first SMR can provide the entire heat demand on its own. The condensing temperature, a nominal 45°C, is below the district-heating water circuit temperature, so the exhaust steam bypasses that heat exchanger and passes directly to the on-board supplementary condensers before being returned as condensate to the hot-well, as before. Under winter conditions the system reverts to the same operating conditions as the first SMR using the '''non-condensing''' turbine. The practical implication of this is in 'summer' mode the turbine can produce an extra 30 MW<sub>e</sub> utilising heat energy that would otherwise be dumped.
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The SMR (I) is designed to operate year-round in CHP mode raising steam (II) to produce electricity via a '''non-condensing''' turbine + generator (III, IV) and using the low pressure exhaust steam to heat a district-heating water circuit (V). Any surplus heat in the form of uncondensed steam is removed by the on-board supplementary condensers (VIII) and the cooling circuit (IX) for these is cooled, in turn, by water drawn from the estuary (X). Hot condensate from the hot well (VII) is pumped (VI) back through the boiler (II) to complete the closed-loop steam circuit.
  
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[[File:SS SMR2.png|800px|frameless|left]]
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[[File:DETAIL SMR1.png|800px|frameless|left]]<br style="clear:both;" />
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Thermo-dynamic analysis for the non-condensing steam turbine (CHP mode) - '''basic steam Rankine cycle'''
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The small modular reactor's pressurised water cooling circuit operating between:
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Coolant Temperature, Core Outlet (°C) 327
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Coolant Temperature, Core Inlet (°C) 296
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{| class="wikitable"
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|-
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!  !! Temperature !! Pressure !! Enthalpy !! Entropy !! Quality !!  !! Work in !! Heat in !! Work out !! Heat out (used)
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|-
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| Units || T/C || P/Bara || h/kJ.kg<sup>-1</sup> || s/kJ.kg<sup>-1</sup>.°C<sup>-1</sup>||  ||  || kJ.kg<sup>-1 || kJ.kg<sup>-1 || kJ.kg<sup>-1 || kJ.kg<sup>-1
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|-
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| Feed Water || 90.0 ||  1  || 377.1 || 1.1928 || #Subcooled liquid ||  ||  ||  ||  ||
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|-
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| Pump Isentropic compression || 90.2 ||  40  || 381.1 || 1.1928 || #Subcooled liquid ||  || 4.0 ||  ||  ||
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|-
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| Heat to Bpt || 250.4 ||  40  || 1087.5 || 2.7968 ||  0  ||  ||  ||  ||  ||
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|-
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| Water - steam || 250.4 ||  40  || 2800.8 || 6.0696 ||  1  ||  ||  ||  ||  ||
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|-
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| Degrees superheat || 39.6 ||  ||  ||  ||  ||  ||  ||  ||  ||
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|-
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| Steam || 290.0 ||  40  || 2933.0 || 6.3133 || #Superheated vapor ||  ||  || 2551.9 ||  ||
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|-
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| Ideal expansion || 102.3 ||  1.1  || 2298.7 || 6.3133 || 0.8309 ||  ||  ||  ||  ||
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|-
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| Real expansion IE=0.85 || 102.3 ||  1.1  || 2393.8 || 6.5667 || 0.8732 ||  ||  ||  || 539.2 ||
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|-
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| Condense & subcool || 90.0 ||  1.1  || 377.1 || 1.1928 || #Subcooled liquid ||  ||  ||  ||  || 2016.7
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|-
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|  ||  ||  ||  ||  ||  ||  ||  ||  ||  ||
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|-
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|  ||  ||  ||  ||  ||  ||  ||  ||  || Work eff. || Heat eff.
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|-
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|  ||  ||  ||  ||  ||  ||  ||  ||  || 21.0% || 79.0%
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|-
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|  ||  ||  ||  ||  ||  ||  ||  || say || 20% || 75%
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|-
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|  ||  ||  ||  ||  ||  ||  ||  ||  || 80 MWe || 300 MWt
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|}

Latest revision as of 11:50, 13 December 2019

For smaller cities with populations from around 130,000 up to 400,000 a ship with a single SMR is deployed.

SS SMR1.png


The SMR (I) is designed to operate year-round in CHP mode raising steam (II) to produce electricity via a non-condensing turbine + generator (III, IV) and using the low pressure exhaust steam to heat a district-heating water circuit (V). Any surplus heat in the form of uncondensed steam is removed by the on-board supplementary condensers (VIII) and the cooling circuit (IX) for these is cooled, in turn, by water drawn from the estuary (X). Hot condensate from the hot well (VII) is pumped (VI) back through the boiler (II) to complete the closed-loop steam circuit.

DETAIL SMR1.png


Thermo-dynamic analysis for the non-condensing steam turbine (CHP mode) - basic steam Rankine cycle

The small modular reactor's pressurised water cooling circuit operating between: 

Coolant Temperature, Core Outlet (°C) 327
Coolant Temperature, Core Inlet (°C) 296


Temperature Pressure Enthalpy Entropy Quality Work in Heat in Work out Heat out (used)
Units T/C P/Bara h/kJ.kg-1 s/kJ.kg-1.°C-1 kJ.kg-1 kJ.kg-1 kJ.kg-1 kJ.kg-1
Feed Water 90.0 1 377.1 1.1928 #Subcooled liquid
Pump Isentropic compression 90.2 40 381.1 1.1928 #Subcooled liquid 4.0
Heat to Bpt 250.4 40 1087.5 2.7968 0
Water - steam 250.4 40 2800.8 6.0696 1
Degrees superheat 39.6
Steam 290.0 40 2933.0 6.3133 #Superheated vapor 2551.9
Ideal expansion 102.3 1.1 2298.7 6.3133 0.8309
Real expansion IE=0.85 102.3 1.1 2393.8 6.5667 0.8732 539.2
Condense & subcool 90.0 1.1 377.1 1.1928 #Subcooled liquid 2016.7
Work eff. Heat eff.
21.0% 79.0%
say 20% 75%
80 MWe 300 MWt
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