Prototype SMR safety system ready for field testing

02 March 2022

X-energy has delivered the first of four sets of equipment for the prototype reactor protection system (RPS) for the Xe-100 small modular reactor (SMR). The equipment, developed by X-energy and Rock Creek Innovations, will enable field testing, validation and optimisation, with results built into the final Xe-100 RPS design.

The Xe-100 RPS development team with the first set of prototype equipment pictured in Rockville (Image: X-energy)

The Xe-100 high-temperature gas-cooled reactor is one of two advanced SMR designs selected by the US Department of Energy (DOE) to receive federal support for the construction of a demonstration plant under the Advanced Reactor Development Program (ADRP). X-energy aims to site a four-unit Xe-100 plant in Washington state as early as 2027.

An RPS is a set of independent and redundant safety and security components that enables the automatic and safe shut down of a nuclear reactor. Xe-100's RPS provides an added layer of protection for the plant and its environment and a design that is simpler than those used in reactors of previous generations, X-energy said.

It uses the Highly Integrated Protection System (HIPS) developed by Rock Creek Innovations and is approved by the US Nuclear Regulatory Commission for safety-related applications. The prototype has taken two years to develop, with X-energy working in close collaboration with Rock Creek Innovations.

"We've modelled how the system would behave in a plant simulator; now we can see how it behaves in real life," said Shawn Hanvy, X-energy digital instrumentation and control engineer.

"The RPS design is an interactive and iterative process that will evolve over time. Unlike typical computer-based protection systems, it won't use any software or microprocessors to operate, relying solely on simple and fixed logic that cannot be changed while in operation. The reduced complexity of the design lowers costs while increasing plant safety and security."

The prototype will help ensure the system functions as intended, support the regulator's understanding of the design, and allow X-energy to begin developing the associated operator training, Jason Pottorf, engineering manager at Rock Creek Innovations, said.

The prototype RPS is to be installed in a mock-up control room in Rockville, Maryland.

The ARDP is designed to help the US domestic nuclear industry demonstrate advanced nuclear reactors through cost-shared partnerships with industry that will deliver two first-of-a-kind advanced reactors to be licensed for commercial operations. In May 2020, the DOE selected TerraPower's Natrium sodium‐cooled fast reactor and X-energy's Xe-100 to receive USD80 million each to build a demonstration plant that can be operational within seven years.

Researched and written by World Nuclear News