Nuclear, O&M, Reactors

Unique barrel pump solving reliability problem at plant

Issue 8 and Volume 101.

Unique barrel pump solving reliability problem at plant

In 1991, Ingersoll-Dresser Pump Co. engineers embarked on a program to develop a centrifugal pump that would solve problems typically faced by positive displacement pumps in the charging systems of pressurized water nuclear reactors. In the past, positive displacement pumps suffered numerous malfunctions, including high packing leakage, shorter plunger life and cracked pump blocks, which caused forced outages.

After analysis, engineers at the company`s Engineered Pump Division in Phillipsburg, N.J., used state-of-the-art hydraulic research, involving low specific-speed impeller designs, to solve the problem. Ingersoll-Dresser Pump Co.`s patented modular impeller, developed for the “WM” vertical inline pump and converted to a multistage diffuser design, ideally fit the hydraulic parameters of the charging system (46 to 160 gpm at 2,500 to 2,800 psi).

Over the next two years, the company`s engineers and marketing officials worked with utilities around the country, analyzing the charging system, as well as making customers aware of the benefits of the new 2 x 10 CAM-12 stage pump. The pump`s unique features provide pump reliability and other system benefits, including low speed, compact design and no external cooling water.

Low speed provides flow stability over a wide operating range without the surging and pulsations common to reciprocating pumps. Ball/ball bearing construction eliminates the need for a forced-feed external lube system, minimizing space requirements and increasing reliability. The pump`s unique stage length reduces the amount of space it requires, allowing it to fit within existing space constraints. Also, a standard bearing arrangement and self-finishing mechanical seals eliminate the need for external cooling water, which reduces the amount of wastewater that must be treated by the plant.

Ingersoll-Dresser Pump Co. received the first CAM order from Union Electric`s Callaway Station in Fulton, Mo. Installed in late 1994, Union Electric`s pump has operated trouble-free since the installation. Other nuclear plants in the United States, as well as South Korea, have since expressed interest in retrofitting their charging systems with the CAM design.

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