Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Manufacture and Erection of SFR
Components: Feedback from PFBR
Experience
FR13, 4-7 Mar 2013, Paris
P.Chellapandi Indira Gandhi Centre for Atomic Research
Kalpakkam, India
FBR’s Role in Nuclear Contribution
0
10000
20000
30000
40000
50000
60000
70000
2010 2012 2017 2022 2032
Nuclear Power Capacity
Projection (in MWe)
----Thermal
Insulation
12
95110Anchor safety
vessel
11
----Core04
5561Inner vessel05
----Transfer Arm06
----Large Rotatable
Plug
07
----SRP/Control Plug08
----IHX09
----Primary Pump10
3644.8Core support
structure
02
3476Grid Plate03
01
No.
116134Main vessel
CFBRPFBR
Weight in tComponent
10 09
07 08
06
04 05
03
02 01
11
12
13
72
5Ø11950
• 40 MWt (13.5 MWe)
• PuC – UC
• Since 1985…
FBTR PFBR CFBR Series MFBR Series
• 500 MWe
• UO2-PuO2 (MOX)
• From 2014…
• 500 MWe
• UO2-PuO2 (MOX)
• From 2023…
• 1000 MWe
• Metallic fuel
• From 2025…
Currently: 4780 MWe (2.3 %)
from 20 reactors
India has a vision of becoming a world leader in fast reactor technology
Schematic of PFBR Flow Sheet
ASS ~ 3000 t; Alloy Steel ~ 500 t,
CS ~ 1000 t; struct. steel ~ 4,06,000 t Lead ~ 320 t ;Concrete ~ 5,02,000 t
Sodium 1750 t
Unique Features of SFR Components
• Large diameter thin walled shell and slender structures calling for
stringent tolerances posing challenges in manufacturing, handling
and erection
• Single side welds are unavoidable at some difficult locations
• In-service inspection is difficult
• Residual stresses should be minimum calling for robust heat
treatment strategy
• Minimum number of materials to be used from reliability point of
view (but not preferred from economic considerations)
• Mainly austenitic stainless steels calling for careful considerations
for welding without significant weld repairs and distortions
• Reactor assembly components decide the project time schedule
(large manufacturing, assembly and erection time)
• Leak tightness is very important in view of resulting sodium leaks
• Limited experience on manufacturing and erection of components
• Design and manufacturing codes still evolving
PFBR Reactor Assembly – Major Lessons
• Grid plate
Large number of sleeves, posing difficulty in assembly, hard facing of
large diameter plates and heavy flange construction
• Roof slab
Large box type structure with many penetrations – complicated
manufacturing process, time consuming and difficulty to overcome
lamellar tearing problems
• Inclined Fuel Transfer Machine
Complex manufacturing processes leading to large time and extensive
qualification tests
• Increase of number of primary pipes – essential for enhancing
safety
• Integration of components manufactured by different industries
took unduly long time
Manufacturing Challenges of Grid Plate
Austenitic stainless steel SS 316 LN
1758 sleeves / 4 nozzles / 1016 studs/ weight = 76 t
Bolted construction
Challenges in assembly
Hard facing of large diameter track with Colomonoy
Feedback: Welded construction with minimum number of sleeves
Hard Facing of Grid Plate Bottom Plate
• Grid plate which supports the core is resting on
core support structure. During any hot shock in
the cold pool, the grid plate temperature raises
from 400oC to 520oC rapidly compared to core
support structure. In order allow the differential
expansion and also to have required rigidity
against seismic forces, slotted bolted system is
provided at the interface.
• In addition, to permit free expansion without
having any risk of self weld, two annular hard
face tracks of diameters 6.38 & 6.77 m are done
on the bottom plate at the interface
Hard facing
Nickel based viz. Colmonoy-5 hard facing
(cobalt based material such as stellite, is avoided
from induced activity considerations
Residual stress measurement after thermal shock s
SS 316LN and Weight = 33 t
909 Sleeves / 734 Spikes / 8 Nozzles / No fasteners
No need of hard facing (minimum differential thermal expansion)
Can accommodate eight pipes
Welded Grid Plate Concept for FBR 1&2
Enhanced Safety Margins with eight primary pipes
• Due to double ended guilotine rupture of one primary pipe, core
flow reduces to 57% (30% for PFBR).
• Consequently, the temperature rise of fuel, clad and coolant are
also less. There is no sub cooled boiling
• The diameter of the pipe reduces from 600 mm (PFBR) to 420 mm
when the flow velocity is maintained same. As a result, pipes
become more flexible, which can accommodate larger thermal
expansions
Temp(oC)
Max temp DSL
Margin
PFBR CFBR PFBR CFBR
Clad hot spot
1073 839 1200 127 361
Bulk Na hot spot
894 724 940 46 216
Challenges in Manufacturing of Roof Slab
PCD 9760
Ø1900 Ø6210
Ø12840
Ø12900
Ø222030000
31500
LAMELLAR TEARING AT ‘T’ & ‘L’ JOINT (Despite UT on Plates & Control on ‘S <0.012’ & ‘P <
0.035’
LAMELLAR
TEARING
ALTERNATE JOINT DESIGNS FOR
AVOIDING LAMELLAR TEARING AT ‘T’ &
‘L’ JOINT
WELD
OVERL
AY
MATERIAL : A48 P2
Feedback: Box type to dome shaped construction
Large box type structure with many penetrations - Fabrication of box
type structure is a very complex, time consuming and difficulty to
handle lamellar tearing problems and to meet dimensional
requirements due to its large dimensions
Dome Shaped Roof Slab
with Skirt Support under Compression
• Dome shape calls for reduced wall thickness,
• Shielding has been be decoupled and transferred directly to
the reactor vault.
• Higher energy absorption potential due to sodium slug impact
under Core Disruptive Accident
• Through machining, it is possible to have minimum annular
spaces that mitigates the sodium release to RCB and aerosol
deposits
PFBR FUEL HANDLING SCHEME
12
FBR 1&2 FUEL HANDLING SCHEME
RCB 1
FB
FTC
SGB 1
SGB 2
EB 1
CB
EB 2
RWB
PFBR
Fig. 2 Layout of NICB
RCB 1
`
DCB
RCB 2
FB
FTC
SA FLASK
TRANSFER
CELL
SGB 1
SGB 2
EB 1
CB
EB 2
CFBR
RCB 1
FB
FTC
SGB 1
SGB 2
EB 1
CB
EB 2
RWB
PFBR
Fig. 2 Layout of NICB
RCB 1
`
DCB
RCB 2
FB
FTC
SA FLASK
TRANSFER
CELL
SGB 1
SGB 2
EB 1
CB
EB 2
CFBR
Significant economic benefits due to
• Replacement of A-frame (IFTM) with St pull gripper inside flask
• Sharing of majority of fuel handling equipment between twin units
FB
RCB
EB1 SGB1
SGB2
CB
EB2
RWB
FB
RCB
RCB
EB1
EB2
CB DCB
SGB 1,2
SGB 3,4
2 RP + 1 TA
2 RP + 2TA
Challenges in Manufacture and Integration of Thermal
Insulation Panels on Safety Vessel
Temp Vs Emissivity
25
45
65
85
105
125
145
165
185
0.00 0.02 0.04 0.06 0.08
emissivity
tem
pera
ture
(C)
Seismic qualification
Arrangement of thin polished sheets
Confirmation of emissivity achieved
Industries involved in PFBR RA Construction
MTAR (Hardfacing by OMPLAS)Grid Plate9
L&T PowaiPrimary Pipe10
GodrejLRP & SRP12
MTAR, HyderabadControl plug13
MTAR, HydrabadCSRDM & DSRDM2
WIL, WalchandnagarCore Catcher7
L&T (SAS with KRR petals)Safety Vessel3
NFC, Hydrabad & L&T HaziraCore Subassemblies1
L&T (SAS with KRR petals)Main vessel4
BHEL, TrichyThermal Baffles inc. cooling pipe5
BHEL, TrichyInner Vessel6
L&T HaziraRoof slab11
WIL,WalchandnagarCore Support Structure8
IndustriesComponentsSl.no
MTAR (Hardfacing by OMPLAS)Grid Plate9
L&T PowaiPrimary Pipe10
GodrejLRP & SRP12
MTAR, HyderabadControl plug13
MTAR, HydrabadCSRDM & DSRDM2
WIL, WalchandnagarCore Catcher7
L&T (SAS with KRR petals)Safety Vessel3
NFC, Hydrabad & L&T HaziraCore Subassemblies1
L&T (SAS with KRR petals)Main vessel4
BHEL, TrichyThermal Baffles inc. cooling pipe5
BHEL, TrichyInner Vessel6
L&T HaziraRoof slab11
WIL,WalchandnagarCore Support Structure8
IndustriesComponentsSl.no
Integration of CSS and Main vessel
Process parameters and sequence of welding finalized based on numerical simulations
Integration of Main Vessel and Roof Slab
Mismatch correction procedure and
methodology established and qualified
Welding sequence established
Distortion control measures identified
Special tools and fixtures developed
Same welders employed for PFBR
Full scale weld mockup and
weld Qualification by HT Testing
• Critical in-situ weld in reactor assembly
• Large mismatch at fit-up stage and limited access for welding
• Tolerance requirement on weld mismatch: t/20 + 2 < 3.5 mm
Transportation Mounted on inner
wall
Placing of pads and
construction of upper
lateral portion of outer wall
Safety Vessel Erection
Transportation Mounting on pads Transmitting the loads to
outer wall through tie
rods
Erection of Main Vessel along with Core Catcher & Grid Plate
Erection of Grid Plate, Inner Vessel & Top shield
Mounting of grid
plate and inner vesselMounting of top shield
Welding of Main Vessel with Top shield
Alignment and fit up of
main vessel and top
shield shell Final assembled view
Step-1
Step-2
Step-3
Step-4
Transportation Mounted on inner
wall
Placing of pads and
construction of upper
lateral portion of outer wall
Safety Vessel Erection
Transportation Mounting on pads Transmitting the loads to
outer wall through tie
rods
Transportation Mounting on pads Transmitting the loads to
outer wall through tie
rods
Erection of Main Vessel along with Core Catcher & Grid Plate
Erection of Grid Plate, Inner Vessel & Top shield
Mounting of grid
plate and inner vesselMounting of top shield
Welding of Main Vessel with Top shield
Alignment and fit up of
main vessel and top
shield shell Final assembled view
Step-1
Step-2
Step-3
Step-4
Computer Application for Manufacturing & Erection
of Reactor Assembly Components
Manufacturing
Technology
Development
Establishing
Machining Capabilities
Heat treatment
Methodologies
Hard facing
Techniques
Manufacture of
Large size dies
Development of Tooling Welding & Inspection
Procedures
Sensitisation of
Indian Industries
Reduce Time for Manufacture
Of PFBR Components
Assembly Procedures
Manufacturing Methodology
for Large Sized Components with
Specified Quality levels
Review of Design &
Manufacturing Requirements
Technology Development of Reactor Assembly Components
Achievements in Manufacturing Technology
Components manufactured under technology development exercises
Erection of Large Dimensioned Vessels
Main vessel into safety vessel Safety vessel into reactor vault
Thermal baffle into main vessel
Inner vessel into main vessel
Grid plate into main vessel Roof slab on the main vessel
• RA and Civil Construction of reactor vault along with safety vessel
are constructed in parallel in matching time schedule that RA will be
erected without time delay
• Subsequently other reactor internals kept ready in SAS will be
introduced
Towards Reducing Construction Time
• Completion time for RA: PFBR ~5 y and ~ 2 y for CFBR
• Scheme arrived at jointly with BHAVINI and Industries