A neutron noise diagnostic methodology for pressurized water reactors

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5906817

Wood, R T

A diagnostic methodology was developed using theoretical models of the neutron power spectral density (PSD) from an ex-core neutron detector and was applied to pressurized water reactor (PWR) plant noise data taken under normal operating conditions. Two applicatons of this diagnostic methodology were performed using plant data. A feedback dynamics model of the neutron PSD was derived from a low-order whole-plant physical model made stochastic using the Langevin technique. From a functional fit to plant data, the response of the dynamic system to changes in important physical parameters was evaluated by a direct sensitivity analysis. In addition, it was possible to relate changes in monitored spectra to changes in physical parameters and to determine detection thresholds using common surveillance discriminants. A resonance model was developed from perturbation theory to give the ex-core neutron detector response for samll in-core mechanical motions in terms of a pole-strength factor, a resonance asymmetry (or skewness) factor, a vibration damping factor, and a frequency of vibration. The mechanical motion parameters for several resonances were determined by a functional fit of the model to plant data taken at various times during a fuel cycle and were tracked to determine trends that indicated vibrational changes of reactor internals. In addition, the resonance model gave the abioity to separate the resonant components of the PSD after the parameters had been identified. As a result, the behavior of several vibration peaks were monitored over a fuel cycle. The systemic approach used in this methodology can provide the basis for automated, on-line diagnostic applications using neutron noise analysis, expert systems, and noise knowledge bases.

• Research Organization: Tennessee Univ., Knoxville, TN (United States)
• OSTI ID: 5906817
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
DATA ANALYSIS
DIAGNOSTIC TECHNIQUES
ENRICHED URANIUM REACTORS
EQUATIONS
FEEDBACK
FUEL CYCLE
FUNCTIONS
IN CORE INSTRUMENTS
LANGEVIN EQUATION
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MECHANICAL VIBRATIONS
NEUTRON DETECTORS
NOISE THERMOMETERS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER DENSITY
POWER PLANTS
POWER REACTORS
PWR TYPE REACTORS
RADIATION DETECTORS
REACTOR COMPONENTS
REACTOR INSTRUMENTATION
REACTOR INTERNALS
REACTORS
SENSITIVITY ANALYSIS
SPECTRAL DENSITY
SPECTRAL FUNCTIONS
THERMAL POWER PLANTS
THERMAL REACTORS
THERMOMETERS
WATER COOLED REACTORS
WATER MODERATED REACTORS