The Implementation of Hot Isostatically Pressed Powder Type 316L/304L Pressure Boundary Components in a PWR Plant

2009 ◽  
Author(s):  
W. Barry Burdett ◽  
Ian D. Hookham
Keyword(s):  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Fine Grain ◽  
Safety Case ◽  
Asme Code ◽  
Powder Type

Hot Isostatic Pressing (HIP) has been used since the 1980s to consolidate porosity in cast metal shapes and improve mechanical properties in conventional forgings and wrought components. The availability of high quality metal powders has made it possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties at reduced cost. Powder HIP manufacturing reduces initial material usage and subsequent machining costs. Metal powder production and HIP processing are automated methods, which also provide protection against forging route obsolescence. Setup costs are lower and batch sizes smaller. HIPped powder microstructures are isotropic and equiaxed, with fine grain sizes not normally achieved in heavy section components, which facilitates ultrasonic NDE examination. Inclusion contents are lower and of more benign geometry, easing fracture and safety case development. Although widely used in the off-shore oil industry in high integrity applications, particularly to reduce welded connections, in the nuclear industry interest has been limited. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components. In an extensive programme of testing, it was established that HIPped powder 316L and 304L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance. HIPped powder items are now in service as pressure retaining components in PWR plant. Effort is now directed at widening the range of components for which the HIP process is appropriate focusing on reducing welds in the plant construction sequence. This is particularly relevant to pipework manufacture and assembly. The benefits of facilitating an ASME Code Case for Powder HIP are also being considered.

Hot Isostatic Pressing of Type 316L Powder for a Pressure Retaining Component

2005 ◽  
Author(s):  
W. Barry Burdett ◽  
Chris T. Watson
Keyword(s):  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Fine Grain ◽  
Safety Case ◽  
Offshore Oil Industry

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When applied to fine metal powders, it becomes possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties at reduced cost. NNS items produced from powder deliver cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which also provide protection against forging route obsolescence. Setup costs are lower and batch sizes smaller. HIPped powder microstructures are isotropic and equi-axed, with uniformly fine grain sizes not normally achieved in heavy section components, which makes ultrasonic NDE examination much easier. Inclusion contents are lower and of more benign geometry, which assists fracture assessment. Use of the technology has grown, particularly in the offshore oil industry where it is already established in high integrity applications, particularly in place of welded joints. Take-up in the more conservative nuclear industry has been slow. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components. In a broad program of testing, Rolls-Royce has established that HIPped powder 316L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance than the forged counterpart. The Safety Case for a thin-walled pressure retaining component has been accepted and implemented.

Hot Isostatic Pressing of Hardfacing and Stainless Steel Powders for PWR Components: Materials and Manufacturing Benefits

2012 ◽  
Author(s):  
W. Barry Burdett
Keyword(s):  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Fine Grain ◽  
High Integrity ◽  
Safety Cases

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When applied to fine metal powders, it is possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties at reduced cost. NNS items from powder deliver cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which provide protection against forging route obsolescence. Setup costs are lower and batch sizes smaller, particularly well suited to small numbers of high integrity components. HIPped powder microstructures are isotropic and equiaxed, with uniformly fine grain sizes not normally achieved in heavy section components, which facilitates ultrasonic NDE examination. Improved features to facilitate NDE are readily incorporated into the HIP assembly. Inclusion contents are lower and of more benign geometry, easing fracture assessment. Use of the technology has grown, particularly in the off-shore oil industry where it is already established in high integrity applications, particularly in place of welded joints. Take-up in the more conservative nuclear industry has been slow. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components. This paper presents a materials perspective on the way in which Rolls-Royce has gained experience with HIPped powders since the 1990s, initially with hardfacing materials to minimise welding defects and provide a robust manufacturing route. Building on this database, we have now established that HIPped powder 316L/304L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance to their forged or cast counterparts. This data is now part of a submission to ASME for inclusion in the Pressure Vessel Code. Rolls-Royce now has a robust methodology in place to develop safety cases and is extending the number of applications in pressure boundary components on current and future classes of equipment. A strength-in-depth argument has been endorsed by external approval organisations and is supporting current submarine build programmes. Other applications in the growing civil nuclear market are now under consideration.

Hot Isostatic Pressing of Type 316L/304K and Monel 400 Powders for Pressure Boundary Components

2006 ◽  
Author(s):  
W. Barry Burdett
Keyword(s):  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Fine Grain ◽  
Monel 400 ◽  
Offshore Oil Industry

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When applied to fine metal powders, it becomes possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties and reduced cost. NNS items from powder deliver cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which also provide protection against forging route obsolescence. Setup costs are lower and batch sizes smaller. HIPped powder microstructures are isotropic and equiaxed, with uniformly fine grain sizes not normally achieved in heavy section components, which facilitates ultrasonic NDE examination. Inclusion contents are lower and of more benign geometry, easing fracture assessment. Use of the technology has grown, particularly in the offshore oil industry where it is already established in high integrity applications, particularly in place of welded joints. Take-up in the more conservative nuclear industry has been slow. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components. In a broad programme of testing, it was established that HIPped powder 316L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance. Work has now been extended to Monel 400 nickel-based alloys and Type 304L. The manufacturing technology has been tailored to produce pressure-retaining components in these alloys for prototype testing.

Type 304L and 316L HIP Powder Processing for PWR Components: Design and Manufacturing Benefits and Safety Case Progress

2010 ◽  
Author(s):  
W. Barry Burdett
Keyword(s):  
Structural Integrity ◽  
Powder Processing ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Implementation Process ◽  
Nuclear Industry ◽  
Metal Powders ◽  
High Integrity ◽  
Safety Cases

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When applied to fine metal powders, it is possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties at reduced cost. NNS items manufactured from powder deliver cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which provide protection against forging route obsolescence. Setup costs are lower and batch sizes smaller, which makes the process particularly well suited to small numbers of high integrity components. HIPped powder microstructures are isotropic and equiaxed, with uniformly fine grain sizes not normally achieved in heavy section components, which facilitates ultrasonic NDE examination. Improved features to facilitate NDE are readily incorporated into the HIP assembly. Inclusion contents are lower and of more benign geometry, easing fracture assessment. Use of the technology has grown, particularly in the offshore oil industry where it is already established in high integrity applications, particularly in place of welded joints. Take-up in the more conservative nuclear industry has been slow. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components. In a broad programme of testing, Rolls-Royce has established that HIPped powder 316L/304L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance than conventional forgings. Rolls-Royce now has a robust methodology in place to develop safety cases and is extending the number of applications in pressure boundary components on current and future classes of equipment. A strength-in-depth argument has been endorsed by external approval organisations and is supporting current submarine build programmes. Other applications in the growing civil nuclear market are now under consideration. A plan for developing an ASME Code Case for Powder HIP is being considered. This paper presents an update on the implementation process.

Hot Isostatic Pressing of Austenitic Stainless Steel Powders for Pressure Retaining Applications

2004 ◽  
Author(s):  
W. Barry Burdett ◽  
Paul Hurrell ◽  
Alan Gilleland
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Structural Integrity ◽  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Nuclear Industry ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Wide Range

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When the technique is applied to fine metal powders, it becomes possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties and reduced cost. Manufacture of NNS items from powder delivers cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which also provide protection against forging route obsolescence. Setup costs are lower and smaller batch sizes possible. HIPped powder microstructures are isotropic and equi-axed, with uniformly fine grain sizes not normally achieved in heavy section components. In austenitic stainless steel materials, this provides significant improvements in ultrasonic NDE (Non-Destructive Examination) in thick sections. Use of the technology has grown, particularly in the off-shore oil industry where it is already established in high integrity applications, but take-up in the more conservative nuclear industry has been slow. In a broad programme of testing, Rolls-Royce has established that HIPped powder 316L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion properties across a wide range of test environments. A methodology for developing robust safety justifications for use has been developed. Manufacture of pressure seal components is now in progress and the economics of other applications such as pump bowls are being considered. The quality of HIPped powder items can provide through life cost savings since there is greater assurance of structural integrity compared to welded or wrought components.

Hot Isostatic Pressing of Inconel 600 and 690 Powders for Pressure Retaining Components

2011 ◽  
Author(s):  
Timothy C. Jelfs ◽  
W. Barry Burdett
Keyword(s):  
Complex Geometry ◽  
Hot Isostatic Pressing ◽  
Cost Savings ◽  
Good Control ◽  
Processing Parameters ◽  
Metal Powders ◽  
Isostatic Pressing ◽  
Inconel 600 ◽  
Inconel Alloys ◽  
Inconel 690

Hot Isostatic Pressing (HIP) has been used for many years to consolidate porosity in cast metal shapes to improve mechanical properties. When applied to fine metal powders, it is possible to produce Near Net Shape (NNS) items and more complex geometry components that are fully dense and offer an attractive set of properties at reduced cost. NNS items produced from HIPed powder deliver cost savings by reducing initial material usage and subsequent machining costs. Powder production and HIP processing are automated methods, which provide protection against forging route obsolescence. Setup costs are lower and batch sizes are smaller, which makes HIPping particularly well suited to small numbers of high integrity components. HIPed powder microstructures are isotropic and equiaxed, with uniformly fine grain sizes not normally achieved in heavy section components, which facilitates ultrasonic NDE examination. Improved features to facilitate NDE are readily incorporated into the HIP assembly. Inclusion contents are lower and of more benign geometry, easing fracture assessment. In a broad program of testing, Rolls-Royce has established (1) that HIPed powder 316L/304L components, in items up to several tons in weight, have equivalent or slightly better strength, toughness and corrosion resistance than the wrought equivalents. Rolls-Royce are extending their activities to HIPing of Inconel alloys. The first phase has been to HIP test samples of Inconel 600 and Inconel 690 alloys. Initial testing has produced promising results in line with expectations of wrought material. There has also been the opportunity to vary the HIPing cycle to assess the effect of processing parameters on the final product. An ability to HIP Inconel components is thought to be of benefit in new plant construction, where material is often not readily available in required thick section. The adaptability and good control of the HIP technique also shows promise as a manufacturing route for future high temperature materials which will be required in Generation 4 civil builds.

Critical Flaw Size Evaluation in Butt-Fusion Joints of HDPE Pipes

2014 ◽  
Author(s):  
S. Kalyanam ◽  
P. Krishnaswamy ◽  
E. M. Focht ◽  
D.-J. Shim ◽  
F. W. Brust ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Nuclear Industry ◽  
Flaw Size ◽  
Fusion Process ◽  
Pipe Material ◽  
Element Analysis ◽  
Hdpe Pipe ◽  
Asme Code ◽  
Critical Flaw ◽  
Pipe Joints

The integrity of high density polyethylene (HDPE) piping and fusion joints are a topic of interest to the nuclear industry, regulators, ASME code, and the plastics pipe industry. The ASME Code Case N-755-1 has been approved and addresses the use of HDPE in safety related applications. Over the last few years some of the concerns identified with the parent HDPE pipe material and the fusion joints have been addressed while others are still being resolved. One such unresolved concern is the effect of the fusion process on the integrity of the joint, specifically, the introduction of flaws during the fusion process. The potential impact of flaws in the fusion joint on the service life of the HDPE piping is being evaluated. The current study calculates stress intensity factors (SIF) for circumferential flaws and uses them to evaluate the potential structural integrity of HDPE fusion joints in pipes. The recent API 579-1/ASME FFS-1 standard provides SIF (KI) solutions to various semi-elliptical and full-circumferential (360°) surface cracks/flaws on the outer surface (OD) and the inner surface (ID). The API 579-1/ASME FFS-1 standard SIF tables and finite element analysis (FEA) of selected cases were used to develop simplified SIF relations for full-circumferential surface flaws that can be used for plastic pipes with diameters ranging from 101.6 mm (4 inch) through 914.4 mm (36 inch) and dimensional ratios (DRs) from 7 through 13. Further, the SIF of embedded flaws akin to lack-of-fusion regions was evaluated. The results from this study serve as precursors to understanding and advancing experimental methods to address important issues related to the critical tolerable flaw size in the butt-fusion joint material and were utilized to select the specimen tests and hydrostatic pipe tests used to evaluate various joining processes. Further, they will help with understanding the essential variables that control the long-term component integrity and structural performance of HDPE pipe joints in ASME Class 3 nuclear piping.

Structural Integrity Evaluation of a Reactor Vessel Outlet Nozzle Weld Inlay

2012 ◽  
Author(s):  
N. L. Glunt ◽  
A. Udyawar ◽  
C. K. Ng ◽  
S. E. Marlette
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Structural Integrity ◽  
Repair Process ◽  
Reactor Vessel ◽  
Nuclear Industry ◽  
Outlet Nozzle ◽  
Weld Material ◽  
Asme Code ◽  
Primary Water

Nickel-base weldments such as Alloy 82/182 dissimilar metal (DM) butt welds used in Pressurized Water Reactor (PWR) nuclear power plant components have experienced Primary Water Stress Corrosion Cracking (PWSCC), resulting in the need to repair/replace these weldments. The nuclear industry has been actively engaged in inspecting and mitigating these susceptible DM butt welds for the past several years. Full and Optimized Structural Weld Overlay as well as Mechanical Stress Improvement Process (MSIP®) are some of the mitigation/repair processes that have been implemented successfully by the nuclear industry to mitigate PWSCC. Three conditions must exist simultaneously for PWSCC to occur: high tensile stresses, susceptible material and an environment that is conducive to stress corrosion cracking. These mitigation/repair processes are effective in minimizing the potential for future initiation and crack propagation resulting from PWSCC by generating compressive residual stress at the inner surface of the susceptible DM weld. Weld inlay is an alternative mitigation/repair process especially for large bore nozzles such as reactor vessel nozzles. The weld inlay process consists of excavating a small portion of the susceptible weld material at the inside surface of the component and then applying a PWSCC resistant Alloy 52/52M repair weld layer on the inside surface of the component to isolate the susceptible DM weld material from the primary water environment. The design and analysis requirements of the weld inlay are provided in ASME Code Case N-766. This paper provides the structural integrity evaluation results for a typical reactor vessel outlet nozzle weld inlay performed in accordance with the ASME Code Case N-766 design and analysis requirements. The evaluation results demonstrate that weld inlay is also a viable PWSCC mitigation and repair process especially for large bore reactor vessel nozzles.

Safety Assessment of Fuel Storage Ponds Following Cooling Faults

2016 ◽  
Author(s):  
Jonathan Webb ◽  
Charles Bridgford
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Spent Nuclear Fuel ◽  
Nuclear Safety ◽  
Nuclear Industry ◽  
Spent Fuel ◽  
Cooling Systems ◽  
External Cooling ◽  
Safety Case

For spent nuclear fuel stored within a cooling pond, the essential nuclear safety functions of control, cooling and containment are fulfilled by maintaining an appropriate depth of water above the fuel. External cooling systems remove the decay heat generated by the spent fuel stored within the pond, in order to maintain the temperature of the water at a constant level. In the event of a fault within these external cooling systems, there is the potential for a temperature excursion within the pond. Historically the UK nuclear industry has considered that such faults would pose no threat to the structural integrity of the pond containment and hence the only loss of water would be due to evaporation following a loss of cooling. However, more recently, it has been recognised that such temperature excursions may result in through-wall cracking leading to a loss of water and undermining of these essential safety functions. This paper outlines the safety case implications of these realisations and the way in which they are being addressed within the UK’s nuclear power stations. The paper considers the effects of thermal transient faults on the concrete pond structure and the potential nuclear safety issues which may occur as a result of this. In response to potential pond cooling faults, consideration is given to the requirement for engineered protection systems along with the safety role of the operator in identifying and responding to faults of this kind. Operators provide a versatile mechanism for identifying fault conditions and taking remedial actions, however, the benefit which can be formally claimed for their role within a safety case is generally limited by the availability or reliability of instrumentation to reveal a fault condition. Post fault operator actions may also be limited by the timescales available following a fault, or by other demands on the operators, which may occur in the event of an external hazard which affects multiple site systems. To quantify the timescales available for post fault remedial action, it is necessary to quantify the rate of water loss from the pond, along with the relationship between pond water depth and the radiological consequences both on-site and off-site. This paper investigates the difficulties which may be encountered in quantifying the role of post fault operator actions within such a safety case, and in demonstrating that the overall nuclear safety risk is acceptably low and as low as reasonably practicable (ALARP).

Failure Analysis Prediction Versus Industry Failure Experience of Air Operated Valves in the Nuclear Industry

2016 ◽  
Author(s):  
L. Ike Ezekoye
Keyword(s):  
Structural Integrity ◽  
Weak Link ◽  
Nuclear Industry ◽  
Functional Requirements ◽  
Strong Basis ◽  
Additional Qualification ◽  
Asme Code ◽  
Qualification Testing ◽  
Failure Experience ◽  
Normal Controls

Safety related valves in the nuclear industry are designed to meet the requirements of the design specifications for the systems in which they are to be installed. In developing valve specifications, systems and valve engineers collaborate to craft the essential requirements needed to support the procurement of the valves that meet the design requirements, and thereby provide reliable service during plant life. The specification requirements, together with the ASME Boiler and Pressure Vessel Code and Standards, provide a strong basis for assuring both structural integrity and functionality of the valve assemblies. The functional requirements cover the duties of the valves. As these valves are safety related, they are generally subjected to preoperational testing and possibly additional qualification testing during manufacture, to ensure that the valves can perform their safety related functions in service. The nuclear experience of engineered products such as valves shows that considerable amount of analysis and documentation of component stresses are performed to ensure compliance with the ASME code and specification requirements. The ASME Code requirements, together with the normal controls applied during manufacture of safety related valves, enhance the reliability of the valves. However, valve failures still occur during plant operation. In this paper, the failures of air operated valves (AOVs) used in nuclear applications were reviewed and the data compared against the failures predicted by valve suppliers based on weak link analysis of the valves. The study shows that there are significant differences between what the suppliers consider structurally likely to fail, what the purchaser expects to fail, and what really fails from field experience. The study shows that field failures are complex. They can be initiated by many factors, most of which are not obvious and cannot be controlled by the valve designer. The complexity of field failures of air operated valves is discussed in this paper.

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