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Hitachi

Hitachi Advanced Plant Performance Diagnosis System “HAPPS”

Overview of HAPPS

To maximize the effective use of nuclear power—a decarbonized energy source—there is a growing need to improve equipment reliability and optimize maintenance. This is essential for increasing operational availability through shorter outage inspection periods and long-cycle operations.
Hitachi has developed the Hitachi Advanced Plant Performance Diagnosis System (HAPPS), which utilizes Data Validation and Reconciliation (DVR) techniques to estimate the “most probable state” of the plant.

HAPPS enables:

  • Detection of steam leaks from normally closed valves
  • High-precision thermal output calculations
  • Extension of instrument calibration intervals
  • Reduction of calibration work volume
  • Optimization of maintenance timing for major components such as heat exchangers and pumps

These capabilities contribute to improved operational availability, optimized maintenance, and enhanced power generation efficiency at nuclear power plants.

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Features of HAPPS

System and Component Performance Monitoring & Health Assessment

  • Based on physical models derived from plant design data, HAPPS minimizes errors caused by instrument drift using DVR techniques. This allows for accurate monitoring of system and component conditions, including performance and degradation.
  • Applicable to reactor systems, turbine systems, and auxiliary cooling systems, it supports the detection of equipment anomalies such as leaks and drift, and evaluation of performance for heat exchangers and pumps.

Thermal Balance Monitoring for Efficiency Improvement

  • By leveraging DVR, HAPPS enables high-precision thermal balance monitoring.
  • Estimates thermal output losses in equipment like heat exchangers and pumps to improve power generation efficiency.

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