The Federal Institute of Physics and Metrology (Physikalisch-Technische Bundesanstalt, PTB) Braunschweig and Berlin is a scientific and engineering state institute and technical superior authority of the Federal Republic of Germany for metrology and physical safety technology. It is the successor of the Physikalisch-Technische Reichsanstalt founded in 1887 in Berlin. The PTB belongs to the portfolio of the Federal Ministry of Economy and Technology. It has about 1650 members of whom about 1300 work in Braunschweig. The tasks and activities of PTB can be divided in four areas: Principles of metrology, Metrology for the legally regulated area, Metrology for the industry, International cooperation.

Alleviating the ailments of a disease but not antagonising its cause.

Parameter values, as they are referred to in the Drinking Water Ordinance (TrinkwV), represent precautionary values and are set at a particularly low level so that even lifelong consumption of the water does not produce harmful effects on a person’s health. The values are based on the latest scientific and toxicological insights. This also ensures that no acute health damage is to be expected even if the parameter values are exceeded for short periods of time.

Statistical value kept by a certain percentage of the measured results of a random sample (e. g. 95 % percentile is the value which is only exceeded by 5 % of the random sample).

Periodic inspections are inspections that are performed periodically at fixed times due to legal regulations, obligations by the authority or other stipulations.

Apart from the necessary regular testing of the material of the pressure retaining boundary of the reactor cooling system and other safety-related pipe systems and containments, the purpose of the periodic inspections is also the regular proof of functional reliability of components of the safety system which are in operational readiness. This is to prevent a failing of components and systems in case of demand to the best possible extent (cf. definition "availability").

Alternative

• Nuclear facility/nuclear installation

A site for the safe and maintenance-free storage of harmful substances for an unlimited period of time.

Permeability e. g. of membranes

1 petabecquerel (PBq) = 10¹⁵ becquerels (Bq) = 1,000,000,000,000,000 becquerels

Science dealing with the composition of rocks, their natural occurrence, their interrelation and their formation and transformation.

Physics: Spatial distance of equal conditions of vibration of two harmonic vibrations.

An elementary particle also known as the quantum of light. This refers to the concept that the energy of electromagnetic radiation always occurs in "packets".

Physiology deals with the physical and biochemical functions of cells, organs and the whole body of creatures.

Water flowing into the mine from various sources. Most of it is a by-product of the mine ventilation.

The plan-approval (licensing) decision is an administrative act with which the admissibility of a project is determined, including all other necessary licences, permits, etc.

Spatial projects are developed and implemented in a planning approval procedure.

94^th element in the periodic system. The isotope Pu-239 (half-life 24,110 years) is of special importance because it is a fissile material. Plutonium is produced by neutron capture from uranium-238 and two following beta decays. Only very small amounts of plutonium occur naturally.

A pooled study (or pooled analysis) combines data from several individual studies that were conducted independently and evaluates the pooled data together. The advantage of such a joint analysis is that the number of study participants is increased, allowing researchers to obtain more meaningful results.

The total volume of a rock is composed of the volume of the solid components and the volume of the cavities or pores in the rock. The total porosity is defined as the ratio of the pore volume and the total volume of the rock. The effective porosity is defined as the ratio of the pore volume usable for the flow of groundwater and the total volume of the rock.

Mineral (Ca(OH)2), calcium hydroxide.

Inherent suitability of a procedure, condition or state to trigger off a damage.

In the area of high-frequency radiation the power flux density is the measure of the strength of the radiation in the far field. Its measuring unit is Watt per square metre (W/m²). It characterises the energy flowing per time unit through an area vertical to the distribution direction of the radiation. If the high-frequency radiation is emitted by an antenna, the following applies: The greater the distance from the antenna the less the power flux density.

Separation of a dissolved substance from a solution.

Power reactor where the heat is discharged from inside the reactor (so-called reactor core) via water which is under high pressure (about 160 bar). Thus boiling is avoided inside the reactor core and simultaneously a high water temperature is achieved in the reactor circuit (so-called primary coolant circuit).

The coolant of the primary coolant circuit gives off its heat in a steam generator to the water of the secondary coolant circuit. The steam generated in this way drives the turbine and the generator to generate electrical current.

(German: Druckwasserreaktor - DWR)

Alternative

• Boiling water reactor

Frequency of a disease at an appointed date.

A preventer is a device drillings are sealed with during the drilling process to prevent gases or liquids from escaping the bore hole.

Primary standards can be measuring instruments or materials, for example. In the calibration lab, the reading from an instrument that is to be tested is compared with a reading from a very accurate measuring instrument (the "standard"). The aim here is to determine the deviation from the standard and the uncertainty of this deviation.

Using a chain of standards, the calibration of a measuring instrument can be traced back to the highest standard in the hierarchy, the primary standard.

Untreated radioactive waste.

Dictum of action stating that preventive measures have to be taken to avoid damage in case of lacking of scientific certainty as to the extent and the consequences of a danger of man and environment (e. g. due to a new technology). In the case of mobile telecommunication the preventive measures concern in particular the informing of the public, the intensification of research and the reduction of exposure.

Profile studies comprise a selection of persons from a target population at a certain date (appointed date). For the selected persons the disease state and the present or earlier exposure are queried simultaneously.

An investigation approach where a defined group of persons is observed anticipatorily over a certain period of time in the future.

Goals worth being protected in legal provisions.

Electrically positively charged particle, together with neutrons it forms the atomic nucleus.

Alternative

• Neutron