A nuclear power plant required required dredging near a secured plant intake to provide a defined amount of water to be available for emergency purposes.
J.F. Brennan Company, Inc., based in LaCrosse, Wisconsin, recently completed the inaugural project for its newest, fully customized Barracuda Class dredge from DSC Dredge, LLC. The Quad Cities Generating Station, a two-unit nuclear power plant located on the Mississippi River near Cordova, Illinois, requires biennial dredging of siltation near the secured water intake area of the plant. The newly commissioned 12-inch by 12-inch swinging ladder cutterhead Barracuda Class “Victor Buhr” was ideal for this project, which began in late April and was completed in late May 2015. The Barracuda Class dredge is a swinging ladder dredge that can also be operated conventionally by locking the ladder in place and pivoting on the stern spud, using swing wires and anchors, which increases the cut width and dredging efficiency. The Victor Buhr has been customized to allow for dredging depths of up to 36 feet. For the Quad Cities project, the dredge was required to work at depths that reached 15 feet.
According to Del Groth, J.F. Brennan Superintendent for the project, “Quad Cities Nuclear requires a defined amount of water to be available for emergency purposes. If it goes out of spec, through too much sand or silt coming close to the secured intake for the plant, then it needs to be cleaned out. Quad Cities has worked with us to do this about every other year for the past 20 years. This year, we worked seven days a week to finish the project within a month.” Groth says the project typically entails dredging approximately 37,000 to 40,000 cubic yards of sand and silt.
At the Quad Cities site, the material was transported 5,000 feet via pipeline from the dredge to one of two onsite containment areas. A DSC booster pump was placed 2,000 feet from the dredge (3,000 feet from the containment area) to ensure consistent production rates and save wear and tear on the dredge pump. “Quad Cities contracts with another company to spread the material 2 to 3 feet thick in the containment area,” Groth notes. Although this is considered to be a remediation project, the dredged material is not toxic. “Because this is a highly secure area, the material stays onsite to support ease in running the plant,” adds Groth.
In January 2015, the Victor Buhr joined eight other DSC dredges in J.F. Brennan’s fleet – including two additional Barracuda Class dredges and six Moray Class dredges. All of J.F. Brennan’s nine DSC dredges are convertible from swinging ladder to conventional design, and all are extensively customized. As the namesake of J.F. Brennan’s Environmental Division Manager Vic Buhr, this newest Barracuda dredge is similarly designed, and Vic Buhr played a large part in the customization of the dredge. Special features for the dredge include a high-viscosity cutterhead, articulated ladder for accuracy, increasing the size of the wing tanks to assist with shallow water projects and moving the hydraulic systems from the wing tanks to the deck of the dredge.