Best Specialty Contracting: Molten Salt Test Loop Project

Specialty Contracting Skills Tested at World’s First Molten-Salt Test Facility in Albuquerque

Photo courtesy J.B. Henderson Construction Co.

The project tests the feasibility of using molten nitrate salt in electricity generation.

Photo courtesy J.B. Henderson Construction Co.

Working around such high temperatures and dangerous chemicals meant that safety was a primary concern.

This first-of-its-kind project allows researchers from around the world to study the feasibility of using molten nitrate salt in electricity generation. The idea dates back to research conducted by the Dept. of Energy in the 1940s, but this is the first large-scale application of the technology in the world.

While sizable, this test loop project is just a scale model of a full production-size generating station that would use optical methods of focusing solar heat energy to produce electricity. In this test facility, heat is generated by a high-capacity furnace instead.

While it is advantageous to use high-temperature heat transfer fluid in these processes, the mixture of 60% sodium nitrate and 40% potassium nitrate at temperatures above 600°C is extremely corrosive to mechanical piping, pumps and instrumentation.

Mechanical contractor J.B. Henderson Construction Co. fabricated and installed the unique specialty equipment and piping. Stainless steel pipe was used to prevent corrosion. The pipe had to be manufactured in Europe in the diameters needed. Some components didn't exist prior to this project, such as custom valve bonnets necessary to maintain heat control throughout the salt flow process. As a result, machinists worked with designer Bridgers & Paxton to design and build the parts.

Since there were no other test facilities in the world on which to model the design, collaboration and detailed building information modeling were key for guaranteeing the successful integration of individual pipe runs, pipe supports, valves and critical electrical and architectural support components.

Working around such high temperatures and dangerous chemicals meant that safety was a primary concern. J.B. Henderson used internal and third-party audits to measure safety performance throughout the project.

When the site's high winds led to concerns about the potential for argon gas to escape the TIG welding torches used to assemble the extensive pipe runs, the team built mobile sheds to shield each welder. The strategy helped the project maintain a spotless safety record.

Key Players

Contractor: Summit Construction, Albuquerque

Owner: Sandia National Laboratories, Albuquerque

Lead Design/MEP: Bridgers and Paxton Consulting Engineers, Albuquerque

Mechanical Contractor: J.B. Henderson Construction Co., Albuquerque

Structural/Civil: Bohannan Huston, Albuquerque

Pipe Stress Engineer: Ambitech, Downers Grove, Ill.

Subcontractors: US Electric; NTS; Merit Insulation; Triangle Paving; Preferred Painting (all Albuquerque)

Submitted by J.B. Henderson Construction Co.

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