Hydrodemolition of the main floor with a specially designed cutting tractor.
Sawcutting of slots in CWB. Tight quarters made planning of work critical to the success of the project.
Intricate scaffolding required to cut slots and perform concrete demo in SWP
Setup of the protective area demonstrated the phasing and challenges of all the equipment that had to be worked around.
Installation of the Cathodic Protection Anodes. Anodes were attached with zipties to a non-conductive spacer to keep it off the reinforcing steel (preventing shorting of the system). Note the required edge distance that the contractor was required to keep near the stands and base plates.
Layout of the rectifier, step-down transformers, resistor-control box and reference electrode junction box upon project completion.
Project Completion - Unit 2 of Intake Structure after floor coatings.

Calvert Cliffs Nuclear Power Plant

Project Description 

In March 2000, Calvert Cliffs Nuclear Power Plant (CCNPP), built by Baltimore Gas & Electric in the 1970s, became the first plant in the United States to earn 20-year extensions of its operating licenses from the U.S. Nuclear Regulatory Commission. CCNPP replaced the steam generators in Units 1 and 2, but when deterioration of steel on the intake floor, circular water pump bowels (CWB) and salt water pits (SWP) became severe, CCNPP contacted STRUCTURAL for assistance. The goal was to repair the concrete surfaces with a system that would help prevent corrosion and last for approximately 20 years to reduce plant maintenance costs.

The scope of work encompassed three main areas: the intake floor, the CWB and the SWP. In order to achieve the owner’s goal, the team utilized an impressed current cathodic protection (ICCP) system to help prevent corrosion of the new and existing reinforcing steel in the floor. With ICCP systems, a small, direct current is passed from a permanent anode to the reinforcing steel. An external power supply is connected between the anode and the steel with the appropriate polarity and voltage to prevent the reinforcing steel from giving up electrons. This system repels chloride ions away from the reinforcing steel toward the installed anode and provides flexibility in adjustment since the current or output can be easily adjusted.