Nuclear energy and radiation terminology · MLC-0119

Nuclear energy and radiation terms: P (41)

• ParentA radionuclide that upon radioactive decay or disintegration yields a specific nuclide (the daughter).
• Parts per million (ppm)Parts (molecules) of a substance contained in a million parts of another substance (e.g., water).
• Pellet, fuelA thimble-sized ceramic cylinder (approximately 3/8-inch in diameter and 5/8-inch in length), consisting of...
• Performance indicatorA quantitative measure of a particular attribute of licensee performance that shows how well a plant is...
• Performance-based regulationA regulatory approach that focuses on desired, measurable outcomes, rather than prescriptive processes...
• Performance-based regulatory actionLicensee attainment of defined objectives and results without detailed direction from the NRC on how these...
• Periodic tableAn arrangement of chemical elements in order of increasing atomic number. Elements of similar properties are...
• Personnel monitoringThe use of portable survey meters to determine the amount of radioactive contamination on individuals, or the...
• PhotonA quantum (or packet) of energy emitted in the form of electromagnetic radiation. Gamma rays and x-rays are...
• Pico-A prefix that divides a basic unit by one trillion (10^(-12)).
• PicocurieOne trillionth (10^(-12)) of a curie.
• PigA colloquial term describing a container (usually lead or depleted uranium) used to ship or store radioactive...
• PileA colloquial term describing the first nuclear reactors. They are called piles because the earliest reactors...
• PipingIndividual pieces that, when joined together, make a piping system. Examples include straight pipes, welds...
• Planned special exposureAn infrequent exposure to radiation, separate from and in addition to the annual dose limits (see 10 CFR...
• Plausible accidentsPostulated events that meet a probability test rather than the more challenging test represented by a...
• PlutoniumA heavy, radioactive, manmade metallic element with atomic number 94. Its most important isotope is fissile...
• Pocket dosimeterA small ionization detection instrument that indicates ionizing radiation exposure directly. An auxiliary...
• Poison, neutronIn reactor physics, a substance (other than fissionable material) that has a large capacity for absorbing...
• Pool reactorA reactor in which the fuel elements are suspended in a pool of water that serves as the reflector...
• PositronParticle equal in mass but opposite in charge to the electron. A positive electron.
• Possession-only licenseA license, issued by the NRC, that authorizes the licensee to possess specific nuclear material but does not...
• Power coefficient of reactivityThe change in reactivity per percent change in power. The power coefficient is the summation of the moderator...
• Power defectThe total amount of reactivity added due to a given change in power. It can also be expressed as the...
• Power reactorA reactor designed to produce heat for electric generation (as distinguished from reactors used for...
• Power uprateThe process of increasing the maximum power level at which a commercial nuclear power plant may operate. This...
• PRA acceptabilityPRA Acceptability describes the ability of a PRA to support risk-informed regulatory decisionmaking. PRA...
• Preliminary NotificationA brief summary report issued by the NRC staff to notify the Commission of the occurrence of a significant...
• Pressure vesselA strong-walled container housing the core of most types of power reactors. It usually also contains the...
• Pressurized-water reactorA common nuclear power reactor design in which very pure water is heated to a very high temperature by...
• PressurizerA tank or vessel that acts as a head tank (or surge volume) to control the pressure in a pressurized water...
• Primary systemA term that may be used for referring to the reactor coolant system.
• Primary water stress-corrosion crackingA stress-corrosion cracking degradation mechanism to which certain materials used in nuclear power plant...
• Probabilistic risk analysisA systematic method for addressing the risk triplet as it relates to the performance of a complex system to...
• Probabilistic risk assessmentA systematic method for assessing three questions that the NRC uses to define "risk." These questions...
• Probability distributionA mathematical characterization of uncertainty. Examples include normal, lognormal, and uniform.
• Production expenseProduction expense is one component of the cost of generating electric power, which includes costs associated...
• Proportional counterA radiation instrument in which an electronic detection system receives pulses that are proportional to the...
• Proprietary informationPrivately owned knowledge or data, such as that protected by a registered patent, copyright, or trademark.
• ProtonAn elementary nuclear particle with a positive electric charge located in the nucleus of an atom.
• Public DoseThe dose received by a member of the public from exposure to radiation or to radioactive material released by...

41 of 555 terms in Nuclear energy and radiation terminology (MLC-0119). Request the full dataset.