| Term | Definition |
|---|---|
| fail-safe | The behaviour of a component or system, following a failure (either internal or external). If a given failure leads directly to a safe condition, the component or system is termed fail-safe with respect to that failure. |
| failure modes and effects analysis | A qualitative systems analysis technique in which the different failures of components are identified and the consequences of those failures on the system or plant as a whole are investigated. |
| Faraday screen | An electrostatic shield composed of wire mesh or a series of parallel wires, usually connected at one end to another conductor which is grounded. Most common application in ITER is to shield the ICRH antenna from the plasma. |
| fast breeder development | The “fast breeder” is a type of fission reactor which uses the high energy (“fast”) neutrons produced by fission reactions directly to create fissile materials (e.g 239Pu or 233U from fertile materisl such as 238U or 232Th respectively). A normal fission reactor uses a “moderator “ such as water or carbon to slow down these neutrons to utilise their heat energy only. Fast breeders have been developed but not deployed due to the low price of fissile fuels and the lack of public support for nuclear fission. |
| fast-wave antennas | Radio frequency antennas used for fast wave current drive (FWCD) techniques. |
| fast-wave current drive | FWCD, a technique for current drive using fast waves. |
| FDR | Final Design Report, usually taken to refer to the first report of the ITER EDA, produced in July 2001. |
| FEM | finite element model |
| FEM stress contours | Finite Element Model, stress contours are a graphical way to represent the value of the stress resulting from the analysis of a component by the Finite Element Model. The stress contours are lines that cover the surface (or a section) of the model, with each line representing a "constant stress" line. |
| ferromagnetic inserts | Plates of ferromagnetic steel included within the vacuum vessel in the shadow of the TF coils to counteract TF ripple. |
| FFMEA | functional failure modes and effects analysis |
| first mirrors | Components (usually of plasma diagnostics or heating systems) which reflect visible light and which are the first material surface seen by plasma radiation. |
| first wall | FW, the interior surface of a tokamak closest to the plasma. |
| flat-top pulse length | The duration a plasma is in quasi-steady state. |
| fluence (neutron) | The time-integrated particle (neutron) flux |
| flux | See “neutron flux”, “heat flux”, or “high-heat flux”. |
| FMEA | failure modes and effects analysis |
| FT-U | Frascati Tokamak Upgrade, Frascati, Italy |
| fuel cycle system | The system which extracts deuterium, tritium and impurities from the plasma exhaust stream and prepares deuterium and tritium for re-injection into the plasma. Also handles waste streams of tritiated gas and tritiated solids to extract the isotope. |
| fuel pellets | Small slugs of frozen deuterium and tritium fuel in the 3-6 mm diameter range fired frequently (between 50 and 7 Hz respectively) into the plasma to maintain sufficient fuel density in the plasma core. |
| Functional Analysis | A method for identifying functional requirements and analyzing performance requirements and dividing them into discrete tasks or activities. It involves the identification and decomposition of the primary system functions into sub-functions at ever increasing levels of detail. |
| functional FMEA | FFMEA, functional failure modes and effects analysis, an extension of the FMEA method applied to functions rather than systems. It starts from a list of plant functions, identifies the ways these functions could fail and then investigates the consequences of such failures on other functions and eventually on plant safety or reliability. |
| functional isolation | Prevention of influences from the mode of operation or failure of one circuit or system on another. |
| fusion | The merging of two light atomic nuclei into a heavier nucleus, with a resultant loss in the combined mass. Fusion is accompanied in general by the release of energy. See also: "controlled thermonuclear fusion". |
| fusion performance | Usually means the level of power amplification, Q, or the energy confinement time. |
| fusion power | The power output from fusion reactions, i.e. in neutrons and alpha-particles. |
| fusion reactor | Usually, a device harnessing fusion power to create electrical power. |
| fusion-fission hybrid | A proposed type of reactor relying on both fusion and fission reactions. A central fusion chamber would produce neutrons to provoke fission in a surrounding blanket of fissionable material. The neutron source could also be used to convert other materials into additional fissile fuels. |
| FW | first wall |
| FWCD | fast wave current drive |
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