Imagine a world where clean, dispatchable electrons can be connected to the grid in less than two years from the start of construction. This would be a game-changer for the nuclear industry and for the planet. OPEN100's construction sequence intends to set a new pace for EPCs that will enable significant cost savings and de-risk capital investments.

See this document for an initial outline and slide below for visual step-by-step.



Mobilization refers to the initial stage of a construction project where preparations occur onsite prior to the commencement of any work. At this point in a project, the contractor has been selected and building plans have typically been approved by the governing municipality.

4 months




Activities include:

  • Secure permits to commence construction activities

  • Deliver and install construction support facilities 

  • Install temporary utilities for construction

  • Install security fence around site


Site Work

Site Work includes all work necessary in connection with the development of the land and the construction of the improvements. This portion of a construction project will include soil work, foundation preparation, and may include sections the main building structure.

5 months




Activities include:

  • Clear site and install roads and parking

  • Profile site and implement site drainage/erosion controls

  • Excavate trenches and fire protection loop 

  • Excavate main plant area down to sub-base elevation

  • Install piling in locations needed for foundation support

  • Backfill and compact soil around buildings to plant grade


Mechanical Erection

Erection is preparing the physical side of the site for the new piece of kit and fitting it in place. This stage involves the installation and professional oversight of major industrial plant facilities and large equipment installation by qualified design engineering companies.

4 months




Activities include:

  • Install reactor, steam generator and pressurizer, cooling pumps

  • Install plant switchgear and interconnect controls

  • Install steam condenser and auxiliary equipment

  • Install turbine generator and auxiliary equipment

  • Install cooling tower module, condensate pumps

  • Install backup power systems

Building Completion

As the facade is completed, the interior fit-out begins with the construction of the interior walls and ceiling framework. Concurrently, the mechanical piping, ductwork, and electrical wiring is put in place concluding with finished materials being applied to the interior components and structures.

6 months




Activities include:

  • Finish roof and make building weather tight

  • Install plant lighting and HVAC

  • Construct interior supplementary steel and platforms/stairways

  • Route mechanical process systems piping, electrical raceways

  • Pull cables and connect to equipment and control centers

  • Finish grade site and final surfacing of roads and parking



During the commissioning phase all the equipment systems needed to operate the entire building are put through a series of rigorous testing procedures before the building can be occupied. The testing begins as the equipment is installed and continues through the early stages of initial operation. 

2 months




Activities include:

  • Energize plant switchgear

  • Pressure test all plant piping and tubing to confirm leak tight

  • Check all electrical wiring for continuity, megger test cables

  • Verify proper alignment of turbine generator

  • System flush to clean lube oil piping 

  • Final connection of pipe to operating configuration


Startup is the final step to confirm that all the systems are designed and installed properly and function as they were intended. This includes a final test that, when completed successfully, provides for the buy-off by the customer and the handover of the system from the vendor to the customer.

2 months




Activities include:

  • Startup of fire protection system, acceptance by authorities

  • Install fuel in reactor vessel

  • Initial operation of the reactor to achieve critical operation

  • Initial operation of reactor system to produce steam

  • Initialize the turbine-generator to full speed/no load status

  • First power generated, acceptance test, commercial operation!

                  is a project of the Energy Impact Center, a Washington, DC based research institute focused on climate restoration.