Speech and Language (eBook)

Advances in Basic Research and Practice

Norman J. Lass (Herausgeber)

eBook Download: PDF | EPUB

2014 | 1. Auflage
326 Seiten
Elsevier Science (Verlag)
978-1-4832-1991-2 (ISBN)

Infos

Speech and Language: Volume 3, Advances in Basic Research and Practice is a compendium of papers that discusses theories, clinical issues, and pathology of language and speech. Some papers discuss theories of phonological development, the encoding/decoding system of language, and the application of phonological universals in speech pathology. Other papers deal with the role of the speech-language clinician, a psychological framework for speech perception, and the formulation of a model for biomechanical analysis of velopharyngeal structure and function. Several papers analyze speech control mechanisms in skilled and non-skilled speakers, the rationale for the delayed auditory feedback (DAF) treatment program, and biofeedback in relation to speech pathology. One paper cites a study of Williams (1974) that shows strategies used in learning a new phonetic system depend upon whether the speaker is still within the critical period for language learning or already well beyond it. The paper notes that if adults can ignore their previously learned sound system and be childlike again in their freedom to experiment and be sensitivity to their own results, then they can achieve supra-segmental and segmental nuances of a new language. The compendium can prove helpful for linguists, ethnologists, psychologists, speech therapists, researchers in linguistics or communications, and general readers interested in speech or learning issues.

Inhalt

Front Cover 1
NUCLEAR POWER PLANT SAFETY AND MECHANICAL INTEGRITY 4
Copyright 5
CONTENTS 6
BIOGRAPHY 8
PREFACE 10
ACKNOWLEDGMENTS 12
ACRONYMS AND DESCRIPTION 14
Chapter 1 - Regulations, Codes, and Standards 18
1.1 REQUIREMENTS 18
1.2 CLASSIFICATION 38
Chapter 2 - Design Basis Loads and Qualification 44
2.1 LOAD DEFINITIONS 44
2.2 LOAD COMBINATIONS 56
2.3 DYNAMIC LOADS 62
2.4 VIBRATION TESTING AND MONITORING 80
2.5 BURIED PIPE 90
2.6 SPECIAL ANALYSES 94
Chapter 3 - Examination and Leak Testing 120
3.1 EXAMINATION 120
3.2 LEAK TESTING 129
Chapter 4 - Suspended Systems 140
4.1 PIPING SYSTEMS 140
4.2 TUBING SYSTEMS 165
4.3 HEATING, VENTILATION AND AIR CONDITIONING DUCT SYSTEMS 171
4.4 CONDUIT SYSTEMS 174
4.5 CABLE TRAYS SYSTEMS 177
Chapter 5 - Supporting Structures 182
5.1 STRUCTURAL STEEL 182
5.2 SUPPORTING CONCRETE 188
5.3 STRUCTURAL WELDING 192
5.4 BOLTING TO STEEL 199
5.5 BOLTING TO CONCRETE 200
5.6 CASE STUDIES 204
5.7 SCAFFOLD 217
5.8 CASE STUDY 224
5.9 COMPONENT CLEARANCES 226
Chapter 6 - Materials and Aging Mechanisms 230
6.1 COMMON MATERIALS 230
6.2 AGING MECHANISMS 234
Chapter 7 - Operability and Industry Operating Experience 252
7.1 OPERABILITY 252
7.2 PIPING AND TUBING SYSTEMS 255
7.3 RACEWAYS AND DUCTS 265
7.4 MECHANICAL EQUIPMENT 269
7.5 STRUCTURAL 282
7.6 INDUSTRY OPERATING EXPERIENCE 289
7.7 EXAMPLES OF IOES 292
Annex 1 - Generic Letters 300
ANNEX 2 - Bulletins 332
INDEX 346

Textauszug

Chapter 2

Design Basis Loads and Qualification

Abstract

Chapter 2 addresses the normal operating loads and postulated accident loads which govern the design of nuclear power plant systems and components. They include normal loads (weight, pressure, thermal expansion), and occasional or postulated loads such as fluid transients, seismic loads, flow-induced vibration (FIV), loads on buried pipe, fatigue, and thermal stratification. We also address in this chapter the concept of leak before break (LBB).

Keywords

Cable Trays and Supports; Design basis loads; Deterministic or probabilistic; Dynamic (time-dependent); Earthquake or Seismic; Electrical conduit and supports; Fatigue; Flow induced vibration; Fluid transients; Frequency and resonance; Heat, Ventilation and Air Condition Systems (HVAC); Hydraulic; Hydrostatic; Leak before break (LBB); Load definitions; Missile; Pipe rupture and whip restraints; Piping and Supports; Pneumatic; Primary or secondary (self-relieving); Service Level A, B, C, or D; Static (constant); Surveillance Testing; Suspended systems; Thermal stratification; Tornado; Tubing and Supports

Chapter 2 addresses the normal operating loads and postulated accident loads which govern the design of nuclear power plant systems and components. They include normal loads (weight, pressure, thermal expansion), and occasional or postulated loads such as fluid transients, seismic loads, flow-induced vibration (FIV), loads on buried pipe, fatigue, and thermal stratification. We also address in this chapter the concept of leak before break (LBB).

2.1. Load Definitions

2.1.1. Suspended Systems

How many types of suspended systems are there in a nuclear power plant?

Suspended systems, also commonly called distribution systems, are continuous systems supported from walls, ceilings, floors, and steel structures. They are the second “S” in the common acronym SSCs (structures, systems, and components). They are in many ways the same types of systems one would find in any power or process plant, they consist of the following categories:

• Piping and Supports. In a nuclear power plant pipes convey liquids (mostly water) and steam or gases. They are made primarily of stainless steel and carbon steel. They are either Safety or Non-Safety Class, depending on their function, as discussed in Chapter 1. By piping systems we mean the pipes themselves and their fittings (elbows, reducers, tees, etc.) and in-line components (valves, instruments, etc.), and their supports.

• Tubing and Supports. Tubing is piping of a custom size, typically called out by its outside diameter and wall thickness. It is often used for instrumentation and sensing lines, and rarely for process systems. Unlike piping, tubing is not fabricated or procured to ASME B16.10 or B16.19 standard pipe schedules. Tubing in nuclear power plants is typically made of small bore (2 in and smaller) stainless steel, and is either welded or joined by specialty fittings which can be dismantled and reassembled for maintenance and instrument calibration.

• Electrical Conduit and Supports. Conduits are tubes containing electrical wiring and cables. They protect long electrical runs of cable and they span from a power source to energized equipment, distribution panels, etc. They are interconnected by junction boxes.

• Cable Trays and Supports. In this application, a bundle of cables spread over flat trays is carried over long distances in the plant, some cable trays are several hundred feet long. Cables inside conduits would land on these trays. Conduit and cable trays are often grouped together and called raceways.

• Heat, Ventilation, and Air-Condition (HVAC) ducting. These are duct systems usually supported by structural steel composed of angle members and bolted steel struts.

What loads apply to the design of piping and tubing systems?

The loading on any given SSC can be categorized in one of several ways: (1) normal load or postulated accident load; (2) service Level A, B, C, or D load; (3) primary load or secondary (self-relieving) load; (4) static (constant) load or dynamic (time-dependent) load; or (5) sustained (applied most of the time) load or occasional (occur once in a while) load.

What are typical static loads?

• Deadweight: The deadweight load includes the weight of the pipe or tubing itself, its contents, the insulation, the in-line components (valves, instruments, etc.), and in some cases a tributary weight of a support that is itself supported in part by the pipe. The deadweight load also includes the water-filled weight of gas or steam lines when they have to undergo a hydrostatic test.

• Internal pressures: We use the plural because a piping system operates at a multitude of pressures, including the test pressure, which is typically larger than the design pressure.

• Thermal modes: We use the plural for this too because there are a multitude of thermal cases that go hand-in-hand with the multiple pressure cases. Thermal loads can in turn be subdivided into two categories: (1) thermal expansion–contraction loads which are global loads on the pipe expanding as a beam structure, including the thermal movements at equipment nozzles, and (2) thermal transients which are local time-dependent temperature fluctuations of the fluid which in turn causes thermal gradients in the metal.

• Building movements: The pipe or tubing attachment points to equipment or structures can expand due to heating or cooling of the buildings. An example is the normal expansion–contraction of the containment with the seasonal change in external ambient temperature. Another example is the expansion of the containment building or compartment walls due to the heating and pressurization that would result from a postulated pipe break inside containment or in a confined room. Finally, there are the attachment point movements of the supports to the building structures due to a seismic event, known as seismic anchor movements (SAMs). Each one of these types of building movements constitutes a separate loading condition. While SAMs are dynamic in nature, they are analyzed statically by applying the largest differential anchor motions to the system.

• Pseudostatic seismic: These are seismic accelerations (“g” loads) applied statically to the distributed weight of the system, in three directions to represent, in a simplified way, the effect of a postulated earthquake. We will see under what conditions this can be done.

• Pseudostatic wind: Wind loading is addressed in Section 3.3.1 of the Standard Review Plan (SRP). Although a wind load is obviously dynamic, it is typically analyzed as a static wind pressure on the pipe. The primary component of this load is the differential pressure across the pipe, which is based on the wind velocity at elevation height, the shape factor of the pipe, and a wind gust factor.

What are typical dynamic loads?

• Seismic inertia: Nuclear power plants are typically designed for two earthquake levels: the operational basis earthquake (OBE) and the safe shutdown earthquake (SSE). One must assume that during the design life of the plant there will be five postulated OBEs, typically classified as Service Level B (upset) events, and one SSE classified as a Service Level D (faulted) event. We have seen, under static loads, that the seismic building motions are applied statically as SAMs. The second component of a seismic load is the inertial load, where the suspended system deforms due to shaking. The seismic inertial analysis can be performed as a time history analysis or a modal superposition analysis. In the seismic time history analysis the seismic accelerations are imposed to the system as a function of time, and the response of the system is also obtained as a function of time. The time history analysis approach is rarely used in design of piping and tubing systems, as it would require multiple artificial time histories to be generated at each support point, and a detailed model for the time-dependent analysis of the system. Instead, the classic seismic analysis is performed using the modal superposition method, with, as input, an envelope of in-structure response spectra (ISRS) of the attachment points to the structures. The modal analysis of piping systems has to apply several standard rules, which are delineated in each plant's FSAR. These include using the correct damping (R.G. 1.61), the correct modal and directional combination (R.G. 1.92), and the correct rigid range (or zero period acceleration) correction (R.G. 1.92). The inertia response and the SAM response may be combined or treated separately, with the inertia load considered a primary load, and the SAM load, which is displacement limited and therefore secondary, added either to the inertia loads or to the secondary loads caused by thermal expansion.

• Hydraulic transient loads: These are addressed in more detail later, but they typically consist of transients caused by liquid water hammer, water-steam cavitation water hammer, steam hammer, or transients caused by the discharge of safety or relief devices.

• Tornado Load: Tornado loading is addressed in Section 3.3.2 of the SRP. The tornado load is composed of three components: (1) the tornado wind pressure load, as described above for wind but at a higher velocity than regular wind. Reg. Guide 1.76 provides tornado wind speeds ranging from...

Produkt-Details

• Erscheint lt. Verlag: 26.1.2016
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber ► Gesundheit / Leben / Psychologie ► Krankheiten / Heilverfahren
• Themenwelt: Medizin / Pharmazie ► Medizinische Fachgebiete ► Allgemeinmedizin
• Themenwelt: Sozialwissenschaften ► Ethnologie
• Themenwelt: Sozialwissenschaften ► Politik / Verwaltung
• Themenwelt: Sozialwissenschaften ► Soziologie
• ISBN-10: 1-4832-1991-7 / 1483219917
• ISBN-13: 978-1-4832-1991-2 / 9781483219912