BWR Main Condenser Retubing

Project Scope
Complete retubing of BWR Main Condenser during refueling outage. In addition to condenser retubing, Williams performed all scaffolding work and built a conveyor system to support transport of materials into work area.

Project Description
Williams managed the overall project execution including materials, equipment, tools, labor, and supervision.

The project included:

• Replacement of 36,860 admiralty brass and titanium main condenser tubes and retubing
• Rigging, removal and replacement of the four inlet waterboxes including new inlet circulating water expansion joints
• Removal and reinstallation of electrical, mechanical and structural interferences to facilitate tube replacement
• Repair of stem-side impingement protection and baffles; installation of tube bundle protection items
• Fabrication of rail transportation system for tubes

Challenges

• 10′ x 10′ Condenser bay egress was limited to access way.
• Large increase in quantity of stakes required. Once project commenced, an additional 42,000 stakes needed attention for a total of 72,000 stakes.
• Oversized hole issues. Tube sheets were found in bad condition.
• Large volume of scope increase.
• Contamination issues.
• Limited RP support.

Project Highlights
Williams was able to complete the project in just 39 days—5 days ahead of schedule—by implementing innovative scheduling, execution and activity re-sequencing. The U.S. record for similar scope projects prior to this outage was 56 days. Throughout the course of the project, Williams faced changes to the scope and plant delays which delayed the schedule by an additional 50 hours. Using Acumen Risk schedule modeling, Williams was able to overcome these challenges. We developed 3-point estimates for every critical path activity, established a risk register and tied the risks to the activities they affected before running the analysis. Using this technique is very unique to this industry and was a major contributor to our predictability.