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Devens Campus

Frequently Asked Questions

Q: What is being built at the 59-acre Hospital Road site in Devens?

A: Commonwealth Fusion Systems (CFS) has built a manufacturing facility, corporate offices and research facility for SPARC — a net energy fusion device currently under construction that will show that fusion can work as a commercial energy source.

Q: Will SPARC generate power?

A: SPARC will demonstrate commercially relevant net energy from fusion for the first time in history. SPARC is not a power plant, but will be a groundbreaking achievement similar to the Kitty Hawk moment for flight, paving the way for commercial fusion energy.

Q: Is the SPARC project at Devens dependent on government funding or tax credits?

A: CFS is almost entirely funded by private investment and we have seen remarkable enthusiasm from the investor community, including leaders in clean energy investment. CFS has also received grants through a U.S. Department of Energy program that funds work at U.S. National Labs and universities to accelerate commercial fusion energy. However, we are not reliant on public funding or subsidies for success at this facility.

Q: Is fusion the same as nuclear power or fission?

A: Fusion is the opposite process to what we commonly refer to as nuclear power or fission. 

Fission is the process of using neutrons to split heavier and unstable elements such as uranium or plutonium to generate energy. Fission has two basic properties that create risk. First, it works via a chain reaction in the fuel, uranium, and that chain reaction has the potential to go unstable. Second, when the uranium fuel ‘fissions’, it produces highly radioactive byproducts, which in the short run generates lots of heat that can cause a meltdown — and in the long run, is the source of long-lived nuclear waste.

During fusion, on the other hand, two light atomic nuclei (such as hydrogen) fuse together to form heavier nuclei such as helium, releasing a neutron and enormous amounts of energy in the process. Fusion does not work via a chain reaction, and therefore cannot go unstable. And the byproduct of the fusion reaction, helium, is a stable element that is used to inflate balloons.

Q: What radioactive materials will be present on site?

A: The SPARC device will use two isotopes of hydrogen as its fuel — an attractive energy source from both an environmental and a safety perspective. The first type, deuterium, is extracted from water and not radioactive. The second type, tritium, is a radioactive isotope of hydrogen with a relatively weak source of beta radiation. It exists in the environment in very low concentrations from both natural and engineered processes. It has a half life of ~12 years. 

Tritium can be found in objects that are self-luminous such as exit signs, watch dials and navigational compasses. SPARC will use miniscule amounts of tritium at a time. In total, there will only be 10 grams of tritium on-site (about the size of two quarters), used over the lifetime of the facility.

Q: What safety provisions are in place related to tritium?

A: Tritium is a substance that must be handled carefully even in the small quantities that we will have on-site. At CFS, we have a culture of “safety first” and have embedded safety into all facets of the design of the facility and its operations. As a result, there will be provisions incorporated into the design of the system and the facility to avoid any loss of tritium. Tritium handling systems, best engineering practices, and operational procedures for hazard management are well-established. CFS has assembled a team of experts to design and engineer robust handling systems for SPARC and future ARC power plants.

Q: Will SPARC produce radiation?

A: SPARC will produce radiation during the fusion process in the form of neutrons. The vast majority of these neutrons are absorbed through materials inside the SPARC machine itself. SPARC is constructed inside a room with thick concrete walls, which also shield neutrons. SPARC will only produce neutrons when operating, and the machine can easily be turned off in a matter of seconds if necessary. The radiation produced by SPARC will be well below allowable levels and will not impact public health.  

Q: Is SPARC safe from severe weather events or other acts of nature?

A: Any act of nature that would cut off power or cause a breach in the facility would cause the fusion process to stop and go back to room temperature immediately. There would be no explosion or potential for meltdown from the fusion process.