EMERSON NA-0112 Ovation®-based Computerenhanced Rod Position Indication System

EMERSON NA-0112 Ovation®-based Computerenhanced Rod Position  Indication System

Description 

This system replaces the electronics portion of the  ARPI system within Westinghouse plants. The system  consists of a detector interface board for each rod,  redundant Ovation controllers and a new computerized  human-machine interface (HMI). This resolves the  issues of difficult and timely calibration and inaccurate  position indication for rods across the power range.

A rod drop test system is included as part of this  upgrade. Plant technical specifications require rod  drop time testing following a refueling outage so that  the rods insert properly and within the time-response  requirements of the plant’s safety analysis. This system  reduces critical path time by automatically analyzing  the data from each rod during a reactor trip and  displaying the results.

Functions include: 

•  Control rod position indication 

•  Control rod bottom alarm 

•  Detector temperature compensation 

•  Detector linearity compensation 

•  Operator alarm capability 

•  One-pass calibration

Features

•  Low-cost installation 

Utilizes the existing linear voltage transducer (LVTs),  eliminating as-low-as-reasonably-achievable concerns  and cost.

•  One-pass calibration

The Ovation-based computer-enhanced rod position  indication system provides simplified, computercontrolled, non-interactive, zero and span (gain)  adjustments.

•  Computer algorithm compensation

Detector ambient temperature and the non-linearity of  the LVT sensors have been compensated for utilizing  custom algorithms based on operating experience.

•  Low detector crosstalk

Two different frequencies are used to drive rod LVTs,  minimizing the negative effect of detector crosstalk.

•  Maintenance and Test Panel

Maintenance programs provide calibration history as  well as single, click-of-the-mouse, computer-controlled  calibration for zero and span settings.

•  Operator Modules

Operator modules are provided to enhance the operator’s  capabilities. The rod information is directed to control  board-mounted flat panel displays and existing plant

Benefits

•  Elimination of deratings and callouts as a result of  limiting condition of operation entry from ARPIincreased profit 

•  Minimization of rod position indication calibration  in start up, resulting in reduced critical path time 

•  Accurate indication of rod position, resulting  in increased operator confidence 

•  Elimination of ARPI work-arounds, serving  to increase operator efficiency 

•  High reliability resulting in lower O&M cost 

•  Existing installations provide low-risk solution 

•  Direct replacement for ARPI and low-cost installation 

•  For rod drop testing, the ability to automatically  perform trending analysis that compares rod drops over  time