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

Achieving Tight Form Tolerances for Large Dia. Thin Shells

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

Thank You