october 27-28, 2004 hapl meeting, pppl 1 thermal-hydraulic analysis of ceramic breeder blanket and...
TRANSCRIPT
October 27-28, 2004HAPL meeting, PPPL
1
Thermal-Hydraulic Analysis of Ceramic Breeder Blanket and Plan for Future Effort
A. René RaffrayUCSD
With contributions from M. Sawan (UW), I. Sviatoslavsky (UW) and X. Wang (UCSD)
HAPL MeetingPPPL
Princeton, NJOctober 27-28, 2004
October 27-28, 2004HAPL meeting, PPPL
2
Outline
• Ceramic Breeder Blanket Layout and Choice of Power Cycle: Brayton
• Thermal-Hydraulics Analysis of Ceramic Breeder Blanket Concept and Power Cycle Optimization
• Next Step: Dual Coolant He/Pb-17Li Concept
• Summary
October 27-28, 2004HAPL meeting, PPPL
3
Ceramic Breeder Blanket Module Configuration (based on ARIES-CS MFE configuration)
• Initial number and thicknesses of Be and CB regions optimized for TBR=1.1 based on:- Tmax,Be < 750°C
- Tmax,CB < 950°C
- kBe=8 W/m-K
- kCB=1.2 W/m-K
- CB region > 0.8 cm
• 6 Be regions + 10 CB regions for a
total module radial thickness of 0.65 m
• Preferable to couple to a Brayton cycle to avoid accident scenario that could result in Be/steam reaction and would
require designing the module box to accommodate high pressure
• Li4SiO4 or Li2TiO3 as possible CB
October 27-28, 2004HAPL meeting, PPPL
4
Adapting an MFE Blanket Design to Laser IFE Must Take into Account the Difference in Heat Loading Characteristics
Key difference between MFE and economically-sized IFE Chambers:
- MFE Wall Load > IFE Wall Load
- But IFE eff. q’’ > MFE q’’
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
6 7 8 9 10
Pfusion
=1800 MW
Chamber Radius (m)
Eff. q''
Wall Load
MFE q'' ~ 0.5 MW/m2
MFE Wall Load > ~ 3 MW/m2
- IFE imposes more demand on first wall cooling
October 27-28, 2004HAPL meeting, PPPL
5
Brayton Cycle Configuration Considered in Combination with CB Blanket + Intermediate HX to Provide Flexibility for Separately
Setting Cycle He Fractional Pressure Drop
IP LPHP
Pout
Compressors
RecuperatorIntercoolers
Pre-Cooler
Generator
CompressorTurbine
To/from In-ReactorComponents or Intermediate
Heat Exchanger
1
2
3
4
5 6 7 8
9 10
1BPin
TinTout
η ,C ad η ,T ad
εrec
• 3 Compressor stages (with 2 intercoolers) + 1 turbine stage; P/P~0.05; 1.5 < rp< 3.0- THX ~ 30°C
- ηcomp = 0.89
- ηturb = 0.93
- Effect.recup = 0.95
• As reported before, we also considered initially a more advanced cycle also with 4 compression stages & 4 turbine stages- It provided good performance
but the pressure drop and pumping power were
unacceptably large and this cycle was not further considered with the CB blanket.
October 27-28, 2004HAPL meeting, PPPL
6
Optimization Study of CB Blanket and Brayton Cycle Using Scaled Volumetric Heat Generation from Neutronics Calculations
• Maximum cycle efficiency (η) as a function of chamber radius (R) under the following assumed constraints:
Be and CB:- Tmax,Be < 750°C
- Tmax,CB < 950°C
- blkt = 0.65 m for breeding
FS:1. Tmax,FS < 550°C; and
2. Tmax,ODS-FS < 700°C
Fusion Power:1. 1800 MW; and 2. 2400 MW
Coolant:- THX = 30°C
- Ppump/Pthermal < 0.05
• η peaks at ~ 36% for R ≥ 9 m for Tmax,ODS-FS < 700°C and for both Pfusion=1800 MW and 2400 MW
• For Tmax,ODS-FS < 550°C, ηis very low, <29% (probably uncacceptable)
• Key constraint is max. FS temp. at FW because of high q’’
• For this concept, we need Tmax,ODS-FS < 700°C; in this case, R=7 m and ηseem a reasonable compromise.
0.20
0.2
0.0
0.
0.40
0.4
6 7 8 9 10
T,max Be<70° ;C T
,max CB<90°C
Ppump
/Pthermal
<0.0T
HX=0°C
,blkt radial
=0.6m
( )Chamber Radius m
Pfusion
=1800 ;MW
T, -max ODS FS
<700°C
Pfusion
=2400 ;MW
T, -max ODS FS
<700°C
Pfusion
=1800 ;MW
T, -max ODS FS
<0°C
October 27-28, 2004HAPL meeting, PPPL
7
Corresponding He Coolant Inlet and Outlet Temperatures
• Maximum allowable temperature of FS limits the combination of outlet and inlet He coolant temperatures
0
400
40
00
0
600
60
6 7 8 9 10
T,max Be
<70° ;C T,max CB
<90°CPpump
/Pthermal
<0.0T
HX=0°C
,blkt radial
=0.6m
( )Chamber Radius m
Pfusion
=1800 ;MW
T, -max ODS FS
<700°C
Pfusion
=2400 ;MW
T, -max ODS FS
<700°C
Pfusion
=1800 ;MW
T, -max ODS FS
<0°C
200
20
00
0
400
40
00
6 7 8 9 10
T,max Be<70° ;C T
,max CB<90°C
Ppump
/Pthermal
<0.0T
HX=0°C
,blkt radial
=0.6m
( )Chamber Radius m
Pfusion
=1800 ;MW
T, -max ODS FS
<700°C
Pfusion
=1800 ;MW
T, -max ODS FS
<0°C
Pfusion
=2400 ;MW
T, -max ODS FS
<700°C
October 27-28, 2004HAPL meeting, PPPL
8
Corresponding Ratio of Pumping to Thermal Power for Blanket He Coolant
• The assumed limit ofPpump/Pthermal < 0.05 can be accommodated with this Brayton cycle.
0
0.02
0.04
0.06
0.08
6 7 8 9 10
T,max Be
<70°CT
,max CB<90°C
THX
=0°C
,blkt radial=0.6m
( )Chamber Radius m
Pfusion
=1800 ;MW
T, -max ODS FS
<700°C
Pfusion
=1800 ;MW
T, -max ODS FS
<0°C
Pfusion
=2400 ;MW
T, -max ODS FS
<700°C
October 27-28, 2004HAPL meeting, PPPL
9
What If the Blanket Was Coupled to a Rankine Cycle With Same Inlet and Outlet Coolant Temperatures
• Gain a couple of points compared to Brayton ( more for lower coolant temperatures); e.g. 38% for R=8 m and Tmax,FS<700°C compared to 36% for Brayton
• Must be considered in combination with penalty of more massive module and possible steam/Be reaction in case of accidents
0.2
0.
0.
0.40
0.4
6 7 8 9 10
T,max Be
<70° ;C T,max CB
<90°CPpump
/Pthermal
<0.0T
HX>10° ( )C pinch point
,blkt radial
=0.6m
( )Chamber Radius m
Pfusion
=1800 ;MW
T, -max ODS FS
<700°C
Pfusion
=1800MW
T,max FS
<0°C
Pfusion
=2400 ;MW
T, -max ODS FS
<700°C
RankineT
S
2
34
56
8'
7reheat
superheat
Pma
x
Pint
4'
8
9
Pmi
n
2'
10
10'
1
m
1-m
Tcool,in
Tcool,out
Example Rankine Cycle
October 27-28, 2004HAPL meeting, PPPL
10
Example MFE Self-Cooled or Dual Cooled Pb-17Li + Ferritic Steel Concept
Example Dual Coolant Concept: FZK DC • Uncouple FW cooling from blanket cooling
– He coolant for more demanding FW cooling (no MHD uncertainties)
– Self-cooled Pb-17Li with SiCf/SiC flow channel insulating inserts for blanket region
– (Note: more flexibility when applying this concept to IFE since there is no MHD effect)
• Use of ODS-steels would allow for higher temperature but more demanding welding requirements
– Compromise: ferritic steel structure with ~mm’s ODS layer at higher temperature FW location
12
12
1
2
1
2Pb-17Li
2
1
He System
Shield
SiCf/SiCChannelInserts
EUROFER Structure(FW+Grids)
ODS LayersPlatedto the FW
• Pb-17Li is an attractive breeder material – Good tritium breeding capability
– Possibility to replenish 6Li on-line
– Almost inert in air
– In general limited extrapolation of blanket technology
• Considered with FS in a dual coolant configuration (ARIES-ST and FZK DC concepts)
Struc. Tmax=550°C
Pb-17Li Tmax=700°C
He Cool. Tmax/P =480°C/14 MPa
Cycle Eff. =45% (Brayton)
Energy Multip. =1.17
Lifetime =15MW-a/m2
October 27-28, 2004HAPL meeting, PPPL
11
Initial Considerations in Applying Dual Coolant Design to IFE
• Example concept consisting of an array poloidal modules- ~ 0.35 m x 0.6 m x 10 m module- Use of SiC insulation to push Pb-17Li temperature
to ~ 700°C (otherwise FS/Pb-17Li compatibility limit ~ 450-500°C)
Illustration of Possible
Dual-Coolant He/LiPb Concept
Pb-17Li Breeding Zones: Large Inner Channels with SiCf/SiC Insulation Layer
~0.35 m
~0.6 m
~10 m
• For R= 7 m and 1800 MW fusion:- He: Tin= 457°C; Tout= 477°C
P= 8 MPa
- FW: V~70 m/s; P/P ~ 0.01 in 1 cm x 2 cm channels
Max. FW FS temp. =700°C
- Pb-17Li: Tin=477°C; Tout= 700°CV~ 0.36 m/s
- Cycle efficiency=45%
October 27-28, 2004HAPL meeting, PPPL
12
Summary
• Scoping study of a Ceramic Breeder design adapted to IFE has been completed.
• High effective FW q’’ impacts design (or any design with He or other coolant with modest heat transfer performance).
• Overall, the achievable cycle efficiency is rather modest with a Brayton cycle (~0.36 or less)
• Rankine cycle would provide slightly better performance (by a couple of points) but would give rise to Be/steam reaction concerns and could lead to a more massive module design.
• Initial analysis indicates the good potential of a dual coolant He/LiPb concpet
• Future effort will focus on:- Finishing the scoping study of this concept (to be presented at next meeting)- Comparative assessment and down selection of the more attractive concept(s) for more
detailed integrated studies.