karlsruhe , november 20/2012 luciano.cinotti@gmail
DESCRIPTION
LEADER Project Working Package 3 – Task 3 . 7 “ Feasibility study of the flat-spiral-tube bundle steam generator with integrated primary pump „. Karlsruhe , November 20/2012 [email protected]. 1. - PowerPoint PPT PresentationTRANSCRIPT
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KarlsruheKarlsruhe,, November 20/2012 November 20/2012
[email protected]@gmail.com
LEADER Project LEADER Project Working Package Working Package 33 – Task – Task 33..77
““Feasibility study of the flat-spiral-tube Feasibility study of the flat-spiral-tube bundle steam generator with integrated bundle steam generator with integrated
primary pumpprimary pump„„
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Task 3.7 Feasibility study of the flat-spiral-tube bundle steam generator with integrated primary pump
The ELSY project, developed in the 6th FP of Euratom, features an innovative configuration with the primary pump installed inside the inner shell of a spiral-tube steam generator.Both components need a careful study to confirm the feasibility and shop manufacturability of the assembly especially challenging due to the specific request of no intermediate tube-welding.Objective of the activity about the variable-speed electrical motor driven pump is the feasibility and installation with support bearings located in the cover gas above the free level of the coolant. The study will include the mechanical inertia necessary to maintain adequate coolant flow rate during pump coast down.Considering the novelty of the steam generator bundle, the Steam Generator main fabrication sequence along with the equipment needed for construction will be identified in order to confirm the feasibility and to provide feedback to the design.The study will indicate also the main on site assembly sequence and a preliminary cost estimate.
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
D39 - Feasibility study of the flat-spiral-tube bundle steam generator with integrated primary pump.
The activity is in progress
Extended-stem Fuel Assemblies
Spiral-tube SG
Primary Pump
Core
The Pump- Spiral-Tube Steam Generator Assembly
The Pump- Spiral-Tube Steam Generator Assembly is one of the main innovations of ELSY/ELFRThe Pump- Spiral-Tube Steam Generator Assembly is one of the main innovations of ELSY/ELFR
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
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Advantages
Feasibility / mechanical issues
Advantages
Feasibility / mechanical issues
The Spiral-Tube Steam Generator
- Del Fungo Giera Energia -
Titolo del documento
Rev. Data Descrizione Elaborazione Verifica Approvazione
Progetto Cl.ris. Identificativo documento Foglio Scala Formato
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
For a given volume the cross section of the STSG perpendicular to the lead flow path is at least 3 time that of a generic SG,
½*Π*(D+d)*h ≥ ¾*Π**D^2( d~1/2*D and in general h>D)
¼*Π*(D^2)
STSG GSG
½*(D-d) ~ ¼*Dh ≥ 1*D
and the length of the lead flow path inside the bundle of the STSG is about 4 times shorter than
that of a generic SG.
1) A STSG can feature a small tube-pitch resulting in a tube bundle with half the volume of a helical-tube SG,
Smaller diameter and shorter reactor vessel 2) while limiting the primary pressure loss to half of that of a helical tube SG. Shorter reactor vessel
Advantages:Remind of the ELSY study on impact of the STSG on primary systemcompactness 1/2
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
3) The free space inside the inner shell of the STSG can be used to locate the primary pump.
Smaller diameter of the reactor vessel
4) The outlet of the cold lead all along the outer shell of the STSG keeps the reactor vessel at uniform cold temperature without need of insulation, “deversoir”, heat exchangers…
Smaller diameter of the reactor vessel
ELSY/ELFR
SPX1
5) A short STSG can be positioned high in the reactor vessel because: - fed from the bottom, does not present risks of gas entrainment. - the radial flow path is not interrupted by a lowered lead free level resulting from a reactor vessel leakage.
Shorter reactor vessel
Advantages:Remind of the ELSY study on impact of the STSG on primary systemcompactness 2/2
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
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Feasibility/mechanical issues
From the web:Spiral Tube Heat Exchangers utilize one continuous Spiral-Wound Tube or several Parallel Tubes in a Circular Pattern connected to Headers on both ends. This Spiral Coil is then installed in a Shell where another fluid is circulated around the outside of the tube.The spaces or gaps between the coils of the spiral tube bundle become the shell side flow path. The profile of a spiral is very compact and fits in asmaller footprint than a shell and tube design. The shell side is usually smaller than a comparable shell and tubedesign and there are no requirements for tube supports or pass dividers.
From the web:Spiral Tube Heat Exchangers utilize one continuous Spiral-Wound Tube or several Parallel Tubes in a Circular Pattern connected to Headers on both ends. This Spiral Coil is then installed in a Shell where another fluid is circulated around the outside of the tube.The spaces or gaps between the coils of the spiral tube bundle become the shell side flow path. The profile of a spiral is very compact and fits in asmaller footprint than a shell and tube design. The shell side is usually smaller than a comparable shell and tubedesign and there are no requirements for tube supports or pass dividers.
ELSY SG vs usual Spiral-tube SGThe shell side radial flow path distinguishes the ELSY-SG from classical Spiral–tube SG with tube side and shell side spiral flow path. Differences in flow path Established technology and feasibility as regard to the Spiral-wound Tube. Need for the SG of ELSY of an adapted tube support system.
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
The tube support system
Several solutions are under investigations ranging from the simplest wavy strips to perforeted interlinked dices
Wavy strips represent a rigid support system and the differential radial displacents must be compensated by the flexibility of the tubes.
Interlinked perforated dices :- Allow relative radial displacement among tubes (particularly important in case of plugged tubes)- Allow relative axial displacements among spires placed at different radial positions)- Provide circumferential porosity to mitigate SGTRA
Interlinked perforated dicesWavy strips
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
Important information on the feasibility of the steam generator is expected from the upcoming manufacturing of a mock up. (out of scope of the LEADER task)..
Besides the use in lead, the STSG can be used for heat recovery from the exhaust gases of the motors of biomass plants.
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
Objectives of the mock up manufacturing and testing
For use in biomass plant:- Performance verification
For use in LFR:- Manufacturing confirmation- Parallel flow stability at low power- Verification of resilience towards differential thermal expansion
The spiral tube SG mock up will be manufactured in Taranto by Tecnomec (a shareholder of M.E.Rivus) and tested in high temperature exhaust gas ( from an oil burner) in the ENEA labs of Saluggia.
Tests in gas does not allow to reproduce the power density of the SG for LFR, but:- severe thermal gradients can be reproduced (gas inlet/outlet T= 600°C/200°C, water/steam inlet outlet T= 80°C/450°C;- through a window it will be possible to observe the tube thermal expansions.
The spiral tube SG mock up will be manufactured in Taranto by Tecnomec (a shareholder of M.E.Rivus) and tested in high temperature exhaust gas ( from an oil burner) in the ENEA labs of Saluggia.
Tests in gas does not allow to reproduce the power density of the SG for LFR, but:- severe thermal gradients can be reproduced (gas inlet/outlet T= 600°C/200°C, water/steam inlet outlet T= 80°C/450°C;- through a window it will be possible to observe the tube thermal expansions.
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
Minimum diameter of the inner spiral (mm) 350Maximum diameter of the outer spiral (mm) 672Number of tubes 18Lenght of tubes (m) 27Outer diameter of tubes (mm) 8Thickness of tubes (mm) 1Radial pitch (mm) 9,5Axial pitch (mm) 9,5
Mock up geometryMock up geometry
Window
Water collector with tubeplate accessible for testing of different ferrules
Tube support with interlinked perforated dices under evaluation
Small diameter tubes make the manufacturing more difficult than in case of a SG for a LFR
PLOF+PLOH: Station Blackout (ELSY)
0
20000
40000
60000
80000
100000
120000
140000
950 1000 1050 1100 1150 1200
Time (s)
Flo
wra
te (
kg/s
)
Core flow
350
400
450
500
550
600
650
950 1000 1050 1100 1150 1200
Time (s)
Te
mp
erat
ure
(°C
)
Core inlet
Core outlet
Max clad
Lead Flowrate at Core Inlet Core Temperatures
Natural circulation in the primary circuit stabilizes at 6% of nominal value after primary pumps trip – Pump inertia (864 kg-m2)
Clad peak temperature of 637 °C at t = 1007 s
……..The study will include the mechanical inertia necessary to maintain adequate coolant flow rate during pump coast down…….
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
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Tubes for lead inlet
A pump shaft diameter progressively increasing towards the free level (tapered shaft with lead inside) is the solution found:- to make uniform the flow rate of lead- to increase the pump inertia without adding steel and without increasing the footprint above the reactor roof.
Motor-shaft-impeller assembly
LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
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LEADER Project “Feasibility study of the STSG with integrated primary pump” Karlsruhe, November 20 /2012
Issue of the deliverable
D39 - Feasibility study of the flat-spiral-tube bundle steam generator with integrated primary pump.
will respect the schedule M36
Deliverable issue