Residual Life Assessment of Light Water Reactor Pressure Vessels

Shah, V.N.; Server, W.L.; Odette, G.R.; Swaroop, A.

doi:10.1520/stp10393s

Cited by 12 publications

(6 citation statements)

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“…More than 80 blades The high cycles which resulted in through-wall cracking included both mechanical and thermal loading con-were cracked, and the resonance frequencies for the stage 9 row of blades ranged from 922 to 5948 cycles ditions. 17,18 The vibration of small-bore piping caused a large number of failures. Other significant sources of per second.…”

Section: E X P E R I E N C E O F V E R Y H I G H -C Y C L E F a T I Gmentioning

confidence: 99%

The fatigue limit and its elimination

Miller

O’donnell

1999

Fatigue Fract Eng Mat Struct

134

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The classical fatigue limit of ferrous metals is a consequence of testing materials at a constant range of cyclic stress and determining the cyclic stress range below which fatigue failures do not occur. This classical fatigue limit of a material is equated to the condition for which fatigue cracks can not propagate beyond microstructural barriers. This paper discusses the causes leading to the elimination of this fatigue limit, including the introduction of transitory cyclic‐dependent mechanisms and time‐dependent processes that will permit a previously non‐propagating crack to grow across the different threshold states expressed in terms of linear‐elastic fracture mechanics (LEFM), elastic–plastic fracture mechanics (EPFM) and microstructural fracture mechanics (MFM). These transitory mechanisms and processes include different loading and environmental conditions, which in a long‐life engineering plant (e.g. 30 years lifetime) can lead to apparently premature failures. Of greater concern is the creation of a new crack‐initiation zone, i.e. a transfer from a surface‐generated crack to an internal‐generated crack that eventually dominates the fatigue failure event. The impact of these conditions on the elimination of the classical fatigue limit necessitates changes in Design Codes of Practice, and such changes are discussed in relation to the extremely long‐lifetime regime (107 < Nf < 1012 cycles‐to‐failure) which is increasingly applicable to the modern day engineering plant.

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Section: E X P E R I E N C E O F V E R Y H I G H -C Y C L E F a T I Gmentioning

confidence: 99%

The fatigue limit and its elimination

Miller

O’donnell

1999

Fatigue Fract Eng Mat Struct

134

View full text Add to dashboard Cite

show abstract

“…Table IIIpresents typical copper and nickel compositions in U.S.light-water-cooled power reactors, as given by Shah et a1 72. For a weld containing moderately high copper and nickel concentrations of 0.25% and 0.7%, respectively, and exposed to a moderately high fluence of2 x 10 19 n/cm 2 , the predicted ~RTNDT would be about 109°C and the predicted decrease in USE would be 46%.…”

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confidence: 93%

Radiation embrittlement in the pressure-vessel steels of nuclear power plants

Wechsler

1989

JOM

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INTRODUCTIONWhen the first commercial nuclear power reactors began operation in the late 1950s and early 1960s, it was well known that the pressure-vessel steel would undergo radiation embrittlement,1 although the related safety implications were not clear. Today, federal regulations require the operators of nuclear power plants to conduct surveillance programs that monitor radiation embrittlement during the service life of a nuclear pressure vessel.Commercial nuclear power reactors in the U.S. are light-water-cooled, pressurized-water reactors (PWRs) and boiling-water reactors (BWRs). The reactor core is contained within pressure vessels made of heavy-section ferritic steel. Because PWRs operate at higher pressures than BWRs (about 16.5 MPa versus about 8.25 MPa), the PWR vessels are smaller and thicker. PWR pressure vessels are typically 3.4-4.3 m in diameter and 20-23 cm thick, while BWR pressure vessels are 5.2-6.4 m in diameter and 15-18 cm thick. Since there is less distance and water shielding between the core and the pressure vessel wall for PWRs, the neutron flux incident on the inner wall is higher. Typical neutron fluxes (fluxes and fluences refer to neutron energies greater than 1 MeV) range from 0.7 x

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“…The Barkhausen effect has been applied in this context for more than two decades [1][2][3]. Its applicability is easy to demonstrate in simple laboratory set-ups, where controlled uniaxial stress change causes significant monotonic variations of magnetic Barkhausen effect (MBN) [4].…”

Section: Introductionmentioning

confidence: 99%

Determination of Magnetisation Conditions in a Double-Core Barkhausen Noise Measurement Set-up

Augustyniak

Piotrowski

et al. 2015

J Nondestruct Eval

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The magnetic Barkhausen effect is useful for assessing 1D and 2D stress states of ferromagnetic steel objects. However, its extension to technically important materials, such as duplex anisotropic steels, remains challenging. The determination of magnetisation inside the studied object and the electromagnet for various geometries, materials and magnetisation angles is a key issue. Three-dimensional, dynamic finite element analysis has been applied to reproduce time-varying fields inside and outside the prototype of a double-core magnetising setup. Useful relationships between characteristics (peak height and location) and magnetic induction vector have been proposed. The qualitative plausibility of simulation has been validated with an experiment and an analytic formula of skin depth. The angular anisotropy of magnetic Barkhausen effect (MBN) in an isotropic sample has been shown in simulation and confirmed experimentally. The numerical model, despite some limitations, seems to be an efficient tool for calibrating stress/MBN relationships at least in isotropic structural steel components.Keywords Electromagnetic finite element method · Dynamic magnetisation of bulk volume · Eddy currents · Magnetic Barkhausen effect (MBN) B Marek Augustyniak

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Residual Life Assessment of Light Water Reactor Pressure Vessels

Cited by 12 publications

References 0 publications

The fatigue limit and its elimination

The fatigue limit and its elimination

Radiation embrittlement in the pressure-vessel steels of nuclear power plants

Determination of Magnetisation Conditions in a Double-Core Barkhausen Noise Measurement Set-up

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