Plus Delta Performance, Inc.
Westinghouse Electric Company, Nuclear Services Division

Wade Heidmann
Manager, Application Engineer
Plus Delta Performance, Inc.
1101 N. Market St. Suite 150
Milwaukee, WI 53202
Voice: (414) 271-1366
Email: wheidmann@pdp.com

The purpose of the EPSS (see Figure 1) is to assist Westinghouse Electric service engineers with the alignment and balancing of nuclear reactor coolant pumps. These large pumps, nearly two stories high including the motor, must maintain minimal vibration when at full speed. If an operator has to shut down a pump because of dangerously high vibration levels, the power plant’s output capabilities may be reduced, which in turn decreases revenue potential. Service engineers may spend anywhere from 3 to 6 weeks at a site refurbishing pumps, which makes scheduling training almost impossible. With new hires, an EPSS was the only practical solution.

The EPSS includes the following major sections:
a. Step-By-Step Instructions
b. Vector Graphing
c. Balancing History
d. Report Features

The EPSS was designed to be graphical and intuitive, with multiple pathways to access information – including menus, indices, and hypertext links. Embedded help, messaging, notepad, and bookmarking features are also included. The goal was for novice engineers to perform at or near the same level as experienced engineers. Summaries of the four major sections follows:

 A. Step-By-Step Instructions

Step-by-step instructions guide the user through each step of an alignment or balancing process (see Figure 2). Users enter critical data from measurements taken or data retrieved from digital equipment connected to the pump. Difficult calculations are then performed by embedded calculators to determine adjustments that need to be made. This reduces the need to memorize complex formulas and the possibility of human error. Experienced engineers can use the advanced balancing section of the application to bypass the step-by-step process and quickly enter data and perform the necessary calculations (see figure 3).

B. Vector Graphing

Balancing a pump requires counterweights to be placed in precise locations on the circumference of a coupling connecting two pump shafts. Calculations are performed with data entered by the user. Vector graphs are drawn by the system based on the user-defined data and the calculations (see Figure 4). These graphs help the user visualize the arrangement of balancing weights and pinpoint the correct location for placement. The graphs can be printed to be included in the engineer’s report.

C. Balancing History

A pump may only be refurbished every 1 to 2 years. Since the same engineer will not always be assigned to the same facility, recording various pump characteristics and related adjustment or repair data is critical. An engineer can learn a lot from the way a pump has performed in the past. The user can look at operating parameters, engineer notes, or vector graphs from a previous balance for a specific pump (see Figure 5). A full historical report can be printed to aid in the analysis of the current job.

D. Report Features

An engineer is required to submit a report for every completed job. Since the EPSS stores all data entered, reports can be easily created. Each report contains diagrams of weight changes and information about pump location, operating parameters, initial vibration data, and post vibration data. The reports also contain general information on the purpose of the work done, a summary of the work done, and any recommendations that the engineer feels may assist in future balancing work for the specified pump.

Prior to development of the Reactor and Coolant Pump Alignment and Balancing EPSS, service engineers were required to rely on their own knowledge and experience when servicing the reactor coolant pump. Training was almost impossible to schedule for new service engineers. All service records were documented on paper and were not easily accessible at the site. Complicated calculations were performed by the service engineer using complex formulas. Vector graphs were created on polar graphing paper. Even if an engineer knew the formulas or knew how to accurately draw vector graphs, there was always room for error.

Users range from new hires to engineers with more than 20 years experience. They are degreed engineers, many with nuclear engineering training and military experience.

1. Service costs are reduced; engineer productivity is improved significantly because EPSS tools provide just the right type and amount of performance support—precisely when it’s needed and at the point of need.
2. Service quality is enhanced because tasks are done more consistently.
3. Call volume for technical support is decreased because the EPSS provides required support at the point of need.
4. Training takes less time, costs less, and is more effective because instructional time is allocated by considering the EPSS work environment—many skills/tasks don’t have to be addressed with conventional training at all because the EPSS is adequate.
5. Expertise is preserved and disseminated in EPSS tools throughout Westinghouse service operations.
6. Customer satisfaction is enhanced substantially because problems are solved faster, downtime is minimized, and operating costs are reduced.
7. Engineers are able to perform critical tasks correctly and predictably without extensive training.