Two of the drivers of plant construction costs are the cost of financing during the construction phase and the substantial amount of skilled-craft-labor hours needed on site during construction.
The AP1000 pressurized water reactor’s extensive use of modularization of plant construction mitigates both of these drivers.
Overnight Construction Cost
From the outset, the AP1000 PWR was designed to reduce capital costs and to be economically competitive with contemporary fossil-fueled plants. This requires lower overnight construction costs and higher confidence in the construction schedule.
The AP1000 plant reduces the amount of safety-grade equipment required by using passive safety systems. Consequently, less Seismic Category I building volume is required to house the safety equipment (approximately 45 percent less than a typical reactor). The AP1000 plant’s modular construction design further reduces the construction schedule and the construction risks, with work shifted to factories with their better quality and cost control as well as labor costs that are less than those at the construction site.
This also allows more work to be done in parallel. The use of heavy lift cranes enables an “open top” construction approach, which is effective in reducing construction time.
With new computer-modeling capabilities, Westinghouse is able to optimize and choreograph the construction plan of an AP1000 unit in advance by simulation. The result is a very high confidence in the construction schedule.
Simplified Plant Arrangement
The AP1000 plant has a smaller footprint than an existing nuclear power plant with the same generating capacity. The plant arrangement provides separation between safety-related and non safety-related systems to preclude adverse interaction between safety-related and non safety-related equipment. Separation between redundant, safety-related equipment trains and systems provides confidence that the safety design functions of the AP1000 reactor can be performed. In general, this separation is achieved by partitioning an area with concrete walls.
The AP1000 plant is arranged with the following principal building structures, each on its own basemat:
- Nuclear Island (the only Seismic Category 1 structure)
- Turbine Building
- Annex Building
- Diesel Generator Building
- Radwaste Building