Nonlinear Ultrasonic Techniques to Monitor Radiation Damage in RPV and Internal Components

Technical Report · Mon Nov 02 04:00:00 EST 2015

DOI:https://doi.org/10.2172/1227268· OSTI ID:1227268

Jacobs, Laurence ^[1]; Kim, Jin-Yeon ^[2]; Qu, Jisnmin ^[3]; Ramuhalli, Pradeep ^[4]; Wall, Joe ^[5]

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1. Georgia Inst. of Technology, Atlanta, GA (United States); Nuclear Energy University Programs
2. Georgia Inst. of Technology, Atlanta, GA (United States)
3. Northwestern Univ., Evanston, IL (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
5. Electric Power Research Inst. (EPRI), Knoxville, TN (United States)

The objective of this research is to demonstrate that nonlinear ultrasonics (NLU) can be used to directly and quantitatively measure the remaining life in radiation damaged reactor pressure vessel (RPV) and internal components. Specific damage types to be monitored are irradiation embrittlement and irradiation assisted stress corrosion cracking (IASCC). Our vision is to develop a technique that allows operators to assess damage by making a limited number of NLU measurements in strategically selected critical reactor components during regularly scheduled outages. This measured data can then be used to determine the current condition of these key components, from which remaining useful life can be predicted. Methods to unambiguously characterize radiation related damage in reactor internals and RPVs remain elusive. NLU technology has demonstrated great potential to be used as a material sensor – a sensor that can continuously monitor a material’s damage state. The physical effect being monitored by NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave. The degree of nonlinearity is quantified with the acoustic nonlinearity parameter, β, which is an absolute, measurable material constant. Recent research has demonstrated that nonlinear ultrasound can be used to characterize material state and changes in microscale characteristics such as internal stress states, precipitate formation and dislocation densities. Radiation damage reduces the fracture toughness of RPV steels and internals, and can leave them susceptible to IASCC, which may in turn limit the lifetimes of some operating reactors. The ability to characterize radiation damage in the RPV and internals will enable nuclear operators to set operation time thresholds for vessels and prescribe and schedule replacement activities for core internals. Such a capability will allow a more clear definition of reactor safety margins. The research consists of three tasks: (1) materials sensing and monitoring; (2) physics-based materials and damage evolution modeling; and (3) remaining life estimation by integrating sensing, modeling and uncertainty.

• Research Organization: Georgia Tech Research Corporation (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE). Nuclear Energy University Programs
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1227268
• Report Number(s): DOE/NEUP--12-3306; 12-3306
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
CRACKS
DISLOCATIONS
EMBRITTLEMENT
FRACTURE PROPERTIES
HARMONICS
IRRADIATION
MONITORING
NONLINEAR PROBLEMS
OUTAGES
PHYSICAL RADIATION EFFECTS
PRECIPITATION
PRESSURE VESSELS
REACTOR INTERNALS
REACTOR SAFETY
RESIDUAL STRESSES
SCHEDULES
SERVICE LIFE
SIMULATION
STEELS
STRESS CORROSION
TIME DEPENDENCE
ULTRASONIC WAVES