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Frequently Asked Questions

Q. When will NIF achieve ignition?

A. Ignition is a grand scientific challenge, making it difficult to predict an exact date when it will be achieved. NIF is currently the only facility that can replicate the conditiions inside the cores of stars and nuclear weapons. To protect the taxpayers' investment in this unique facility, NIF will produce these extreme temperatures and pressures by carefully increasing the laser energy and neutron yield in experiments over the coming months. NIF researchers will study the reactions leading up to fusion ignition in order to fine-tune the lasers and targets prior to attempting ignition. These experiments will gather data from sophisticated diagnostic equipment inside the target chamber and close to the target; many of these diagnostics would not be able to operate inside the target chamber under ignition conditions. We will gain a better understanding of the ignition process with each experiment and hope to achieve fusion ignition via NIF within the next two years. Regular updates on our progress will be posted on the NIF Website.

Q: What kinds of experiments will NIF primarily conduct—national defense or fusion energy?

A: The vast majority of NIF experiments conducted since construction of the NIF laser was completed in March 2009 have been devoted to the U.S. Stockpile Stewardship Program (SSP). This includes the experiments conducted in support of the NIF ignition goal. Ultimately, approximately 85% of NIF experimental time is intended for use by the SSP. The remaining 15 percent will be devoted to fundamental science and other activities.

Ignition is an important goal for Stockpile Stewardship and will also prove the scientific feasibility of inertial confinement fusion (ICF) as a clean source of energy. The National Academy of Sciences began a two-year study in late 2010 to help map out the future course for inertial fusion energy.

Q. Do these experiments present any danger to the public?

A. No. While the temperatures and pressures involved in creating a controlled fusion reaction are extreme, NIF has been designed to ensure that the process is completely safe. Inertial confinement fusion is an inherently safe process: the ignition "event" is very small—about the diameter of a human hair—and lasts for only a few trillionths of a second. The energy released is limited by the very small amount of fuel in the target capsule and is completely contained in the target bay.

Q. NIF will use tritium, a radioactive substance. How much tritium will be used in each shot, and what are the hazards?

A. A NIF target capsule is smaller than a peppercorn and contains less than 1 milligram of tritium. That amount of tritium corresponds to less than 10 curies of radioactivity (a curie is a measure of radioactivity). This is about half the amount of radioactivity contained in a commercially available tritium-powered "Exit" sign. Even though the amount of tritium used by NIF is extremely small, extensive precautions, including state-of-the-art tritium handling capabilities, have been provided to ensure that the tritium is properly controlled (see Target Chamber).

Q: Is there any possibility that a NIF experiment could create a black hole?

A: No. When the NIF target capsule implodes, the tiny "star" that will be created will explode in a burst of energy lasting just a few trillionths of second, fusing hydrogen nuclei into helium nuclei and releasing neutrons and kinetic energy in a reaction similar to what happens continuously in the sun and healthy stars. This process is different from the gravitational collapse of a burned-out star into a black hole, or the theoretical creation of miniature black holes due to the collision of ultra-high-energy cosmic rays striking the Earth's atmosphere. Fusion experiments on NIF will not involve either enough mass or enough energy to create black holes.

Q. How much did NIF cost?

A. The total cost for the NIF enterprise including development, vendor costs, capital, installation, and commission costs was $3.54 billion.

Q. What is LIFE?

A. LIFE, an acronym for Laser Inertial Fusion Energy, is a baseline power plant concept being developed as an extension of the technology demonstrated on NIF. A LIFE power plant would use nuclear fusion—a carbon-free, inherently safe, and virtually unlimited energy source—to generate electricity.

Q. How do NIF and LIFE differ?

A. NIF was not designed as a power plant. NIF was built without active cooling of its glass lasers; to allow time for the lasers to cool, NIF plans to fire up to three shots a day. An inertial fusion energy power plant such as LIFE would need to fire 10 to 15 shots per second. LIFE is an advanced energy concept that will build on the physics and technology developed for NIF. LIFE has the potential to meet future worldwide energy needs in a safe, sustainable manner without carbon dioxide emissions.

Q: Tritium is rare and very expensive to produce. How would a fusion power plant get the tritium it needs to sustain continuous fusion reactions?

A: It's true that tritium exists only in small quantities in nature, so a fusion energy power plant would need to create its own tritium fuel. The neutrons generated in the fusion reaction will be absorbed within a liquid salt blanket surrounding the fusion chamber to create a hot fluid that will turn a turbine to generate electricity. The salt will contain lithium, which will react with the fusion neutrons to produce helium and tritium. Due to neutron multiplication reactions, it is possible to make more than one triton (tritium nucleus) for each one consumed in fusion reactions, creating a net positive generation of tritium. This tritium is then sent to the target factory to be used to produce new targets.

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