Jigar Raval - Academia.edu (original) (raw)

Papers by Jigar Raval

2013 IEEE 25th Symposium on Fusion Engineering (SOFE), 2013

ABSTRACT ITER vacuum vessel is a double wall structure, comprising of inner and outer shells. Spa... more ABSTRACT ITER vacuum vessel is a double wall structure, comprising of inner and outer shells. Space between two shells is filled up with ITER vacuum vessel In-Wall Shielding blocks to, (i) provide neutron shielding to toroidal magnetic field coil and (ii) reduce toroidal magnetic field ripple. There are about 8960 IWS blocks of different sizes, shapes and materials distributed over nine vessel sectors and corresponding nine field joints. Manufacturing of IWS requires various processes like water jet cutting, precision CNC machining, assembly with tight tolerances, accurate dimension measurements, spot welding, full penetration welding, Non Destructive Testing etc. Various IWS mock ups are manufactured to establish and validate manufacturing and inspection procedures. With sufficient experience gained from manufacturing and testing of mock ups, final manufacturing of IWS has started at M/s. Avasarala Technologies Limited, India. This paper describes important features of IWS design, results of mock ups' manufacturing, optimization of manufacturing and inspection processes, assembly and progress of actual IWS manufacturing.

2013 IEEE 25th Symposium on Fusion Engineering (SOFE), 2013

The main functions of the ITER Vacuum Vessel (VV) are to provide the necessary vacuum for plasma ... more The main functions of the ITER Vacuum Vessel (VV) are to provide the necessary vacuum for plasma operation, act as first nuclear confinement barrier and remove nuclear heating. The design of the VV has been reviewed in the past two years due to more advanced analyses, design modifications required by the interfacing components and R&D. Following the signature of four Procurement Arrangement (PAs), the manufacturing design of the VV sectors, ports and In-Wall Shielding (IWS) is being finalized and the fabrication of the VV sectors has been started in 2012.

Fusion Engineering and Design, 2014

h i g h l i g h t s • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. ... more h i g h l i g h t s • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. • Manufacturing results of real scale mock-ups. • Manufacturing status of the VV in domestic agencies.

Fusion Engineering and Design, 2014

The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double wal... more The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double walls of the VV is filled with in-wall shielding (IWS) and cooling water. The main purpose of the in-wall shielding is to provide neutron shielding together with the blanket and VV shells and water during ITER plasma operation and to reduce the ripple of the Toroidal magnetic field. Based on ITER vacuum vessel structure and related requirements, in-wall shielding are designed as about 8900 individual blocks with different sizes and several different materials distributed over nine vessel sectors and nine field joints of vessel sectors. This paper presents the design of the IWS, considering loads, structural stresses and assembly method, and also shows neutron shielding effect and TF ripple reduced by the IWS.

Journal of Physics: Conference Series, 2017

Journal of Physics: Conference Series, 2017

In-Wall Shielding (IWS) is one of the important components of ITER Vacuum Vessel (VV) which fills... more In-Wall Shielding (IWS) is one of the important components of ITER Vacuum Vessel (VV) which fills the space between double walls of VV with cooling water. Procurement Arrangement (PA) for IWS has been signed with Indian Domestic Agency (INDA). Procurement of IWS materials, fabrication of IWS blocks and its delivery to respective Domestic Agency (DA) and ITER Organization (IO) are the main scope of this PA. Hence, INDIA is the only country which is contributing to VV IWS among all seven ITER partners. The main functions of the IWS are to provide Neutron Shielding with blanket, VV shells and water during plasma operations and to reduce ripple of the Toroidal Magnetic Field. To meet these functional requirements IWS blocks are made up of special materials (Borated Steels SS304 B4 & SS304 B7, Ferritic Steels SS 430, Austenitic Steel SS 316 L (N)-IG, XM-19 and Inconel-625) which are qualified, reliable and traceable for the design assessment. The choice of these materials has a significant influence on performance, maintainability, licensing, detailed design parameters and waste disposal. The main reasons for the materials selected for IWS are its high mechanical strength at operating temperatures, water chemistry properties, excellent fabrication characteristics and low cost relative to other similar materials. All the materials are qualified with respect to their respective codes (ASTM/EN standards with additional requirements as described in RCC-MR code 2007) and ITER requirements. Agreed Notified Body (ANB) has control conformity of materials certificates with approved material specification and traceability procedure for Safety Important Component (SIC). The procurement strategy for all the IWS materials has been developed in close collaboration with IO, ANB and Industries as per Product Procurement Specification (PPS). The R&D for sample, bulk material production, testing, inspection and handling as required are carried out by IN DA and IO. At present almost all IWS materials (~2500 Tons) has been procured by IN DA with spares to manufacture ~9000 IWS blocks. This paper summarizes IWS material selection, qualification and procurement processes in detail.

2015 IEEE 26th Symposium on Fusion Engineering (SOFE), 2015

The ITER In-Wall Shielding (IWS) consists of blocks sandwiched between inner and outer shells of ... more The ITER In-Wall Shielding (IWS) consists of blocks sandwiched between inner and outer shells of the ITER Vacuum Vessel. Typically an IWS block is assembled to vessel by first fixing a lower bracket to the vessel rib, followed by putting the block on the bracket and then fixing the upper bracket to block and rib using bolts and cap screws. As the ITER Vacuum Vessel consists of several ports and penetrations, the IWS block is aligned along different paths and angles before putting the block on the Vessel. A conventional system cannot handle the heavy IWS blocks with required flexibility, hence a mechanical system is proposed to assemble the IWS blocks at multiple degrees of freedom with fine accuracy. This paper describes a mechanical system proposed to assemble the blocks at the configuration with the required precision.

2013 IEEE 25th Symposium on Fusion Engineering (SOFE), 2013

ABSTRACT ITER vacuum vessel is a double wall structure, comprising of inner and outer shells. Spa... more ABSTRACT ITER vacuum vessel is a double wall structure, comprising of inner and outer shells. Space between two shells is filled up with ITER vacuum vessel In-Wall Shielding blocks to, (i) provide neutron shielding to toroidal magnetic field coil and (ii) reduce toroidal magnetic field ripple. There are about 8960 IWS blocks of different sizes, shapes and materials distributed over nine vessel sectors and corresponding nine field joints. Manufacturing of IWS requires various processes like water jet cutting, precision CNC machining, assembly with tight tolerances, accurate dimension measurements, spot welding, full penetration welding, Non Destructive Testing etc. Various IWS mock ups are manufactured to establish and validate manufacturing and inspection procedures. With sufficient experience gained from manufacturing and testing of mock ups, final manufacturing of IWS has started at M/s. Avasarala Technologies Limited, India. This paper describes important features of IWS design, results of mock ups' manufacturing, optimization of manufacturing and inspection processes, assembly and progress of actual IWS manufacturing.

2013 IEEE 25th Symposium on Fusion Engineering (SOFE), 2013

The main functions of the ITER Vacuum Vessel (VV) are to provide the necessary vacuum for plasma ... more The main functions of the ITER Vacuum Vessel (VV) are to provide the necessary vacuum for plasma operation, act as first nuclear confinement barrier and remove nuclear heating. The design of the VV has been reviewed in the past two years due to more advanced analyses, design modifications required by the interfacing components and R&D. Following the signature of four Procurement Arrangement (PAs), the manufacturing design of the VV sectors, ports and In-Wall Shielding (IWS) is being finalized and the fabrication of the VV sectors has been started in 2012.

Fusion Engineering and Design, 2014

h i g h l i g h t s • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. ... more h i g h l i g h t s • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. • Manufacturing results of real scale mock-ups. • Manufacturing status of the VV in domestic agencies.

Fusion Engineering and Design, 2014

The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double wal... more The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double walls of the VV is filled with in-wall shielding (IWS) and cooling water. The main purpose of the in-wall shielding is to provide neutron shielding together with the blanket and VV shells and water during ITER plasma operation and to reduce the ripple of the Toroidal magnetic field. Based on ITER vacuum vessel structure and related requirements, in-wall shielding are designed as about 8900 individual blocks with different sizes and several different materials distributed over nine vessel sectors and nine field joints of vessel sectors. This paper presents the design of the IWS, considering loads, structural stresses and assembly method, and also shows neutron shielding effect and TF ripple reduced by the IWS.

Journal of Physics: Conference Series, 2017

Journal of Physics: Conference Series, 2017

In-Wall Shielding (IWS) is one of the important components of ITER Vacuum Vessel (VV) which fills... more In-Wall Shielding (IWS) is one of the important components of ITER Vacuum Vessel (VV) which fills the space between double walls of VV with cooling water. Procurement Arrangement (PA) for IWS has been signed with Indian Domestic Agency (INDA). Procurement of IWS materials, fabrication of IWS blocks and its delivery to respective Domestic Agency (DA) and ITER Organization (IO) are the main scope of this PA. Hence, INDIA is the only country which is contributing to VV IWS among all seven ITER partners. The main functions of the IWS are to provide Neutron Shielding with blanket, VV shells and water during plasma operations and to reduce ripple of the Toroidal Magnetic Field. To meet these functional requirements IWS blocks are made up of special materials (Borated Steels SS304 B4 & SS304 B7, Ferritic Steels SS 430, Austenitic Steel SS 316 L (N)-IG, XM-19 and Inconel-625) which are qualified, reliable and traceable for the design assessment. The choice of these materials has a significant influence on performance, maintainability, licensing, detailed design parameters and waste disposal. The main reasons for the materials selected for IWS are its high mechanical strength at operating temperatures, water chemistry properties, excellent fabrication characteristics and low cost relative to other similar materials. All the materials are qualified with respect to their respective codes (ASTM/EN standards with additional requirements as described in RCC-MR code 2007) and ITER requirements. Agreed Notified Body (ANB) has control conformity of materials certificates with approved material specification and traceability procedure for Safety Important Component (SIC). The procurement strategy for all the IWS materials has been developed in close collaboration with IO, ANB and Industries as per Product Procurement Specification (PPS). The R&D for sample, bulk material production, testing, inspection and handling as required are carried out by IN DA and IO. At present almost all IWS materials (~2500 Tons) has been procured by IN DA with spares to manufacture ~9000 IWS blocks. This paper summarizes IWS material selection, qualification and procurement processes in detail.

2015 IEEE 26th Symposium on Fusion Engineering (SOFE), 2015

The ITER In-Wall Shielding (IWS) consists of blocks sandwiched between inner and outer shells of ... more The ITER In-Wall Shielding (IWS) consists of blocks sandwiched between inner and outer shells of the ITER Vacuum Vessel. Typically an IWS block is assembled to vessel by first fixing a lower bracket to the vessel rib, followed by putting the block on the bracket and then fixing the upper bracket to block and rib using bolts and cap screws. As the ITER Vacuum Vessel consists of several ports and penetrations, the IWS block is aligned along different paths and angles before putting the block on the Vessel. A conventional system cannot handle the heavy IWS blocks with required flexibility, hence a mechanical system is proposed to assemble the IWS blocks at multiple degrees of freedom with fine accuracy. This paper describes a mechanical system proposed to assemble the blocks at the configuration with the required precision.