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Appendix F: Glossary; Part N - Z

n: Number of measurements from a survey unit used to conduct a statistical test.

N: N = m + n, is the total number of measurements required from the reference area and a survey unit. See m and n.

NAD: Nicotinamide Adenine Dinucleotide.

NaI: sodium iodide.

NaI scintillator: A device that uses crystals made of an alkali-halide salt to detect high levels of radionuclides. When an NaI crystal is hit by high-energy gamma rays, the crystal produces charged particles that react within the crystal itself to emit lower energy photons in the visible range. This detector is used when simple spectra resulting from few radionuclides are expected.

NAPL: Non-Aqueous Phase Liquid.

NARM: Naturally occurring or Accelerator-produced Radioactive Material, such as radium, and not classified as source material.

natural flushing: The application of the existing groundwater flow and geochemical attenuating conditions to flush (remove) the contaminant from the region of concern.

naturally occurring radio-nuclides: Radio-nuclides and their associated progeny produced during the formation of the earth or by interactions of terrestrial matter with cosmic rays.

natural radiation: Radiation originating from the decay of naturally occurring radionuclides, and cosmic radiation.

NCRP: National Council on Radiation Protection and Measurements.

NDA: Nuclear Decommissioning Authority.

neutron: Uncharged particle, constitutes approximately 50 per cent by mass of most atomic nucleii.

neutron flux: A measurement of the intensity of a neutron source (measured in J/cm2.s or neutrons/cm2.s).

nf: The number of samples that should be collected in an area to assure that the required number of measurements from that area for conducting statistical tests is obtained. Nf = n/(1-R).

NGO: Non-Governmental Organisation.

NIM: Nuclear Instrument Model.

non-blind measurement: Non-blind measurements are measurements that have a concentration and origin that are known to the individual performing the measurement. See single-blind measurement and double-blind measurement.

non-conformance: A deficiency in characteristic, documentation, or procedure that renders the quality of an item or activity unacceptable or indeterminate; non-fulfilment of a specified requirement(s).

non-impacted area: Areas where there is no reasonable possibility (extremely low probability) of residual contamination. Non-impacted areas are typically located off-site and may be used as background reference areas.

non-parametric test: A test based on relatively few assumptions about the exact form of the underlying probability distributions of the measurements. As a consequence, nonparametric tests are generally valid for a fairly broad class of distributions. The Wilcoxon Rank Sum test and the Sign test are examples of nonparametric tests.

non-radioactively contaminated land: Any land in, on or under (including groundwater) which there are non-radioactive contaminants above natural and artificial background levels that are typical of the area of a country in which the site is located.

NORM: Naturally Occurring Radioactive Material.
normal (gaussian) distribution: A family of bell shaped distributions described by the mean and variance.

normalization of data: A conversion of older (uncalibrated) radiometric data to a new reference level.

NPP: Nuclear Power Plant.

NRC: United States Nuclear Regulatory Commission.

NRPB: National Radiological Protection Board (United Kingdom).

nuclear fission: Process by which an atom splits into two or more pieces, each of which is an entirely separate nuclide.

nuclear-licensed site: Sites that are regulated by national laws. The Act can apply to fixed sites for the purposes of constructing and operating nuclear reactors and other prescribed nuclear installations. The guidance applies to operating sites and those being decommissioned, whether or not they are to be delicensed.

nuclear radiation: Radiation originating by disintegration of unstable atomic nuclei.

objective: An aim set for the management of contaminated land. Objectives are set by considering factors such as government policy, corporate/organisational policy and the views of stakeholders. It is recommended that environment, health and safety objectives are established separately from those of a commercial and administrative nature.

OPC: Ordinary Portland Cement.

optimisation: The form, scale and duration of the intervention (remedial action) maximises the net benefit. The principle of optimisation means that there is no predetermined end point for remediation that is applicable in all circumstances. In the extension to Part 2A, where a remediation scheme addresses significant pollutant linkages, some but not all, of which relate to lasting exposure, any intervention should be optimised having regard to their benefit in respect of any remedial treatment actions relating to non-radioactive significant pollutant linkages.

option: A method, approach or technology that can be used for land management. Options can include, but may go further than, some or all of the actions defined as ‘remediation’. In evaluating options, consideration should always be given to ‘doing nothing more’ to the contamination or to removing contamination to background levels. See also strategy.

organization: a company, corporation, firm, government unit, enterprise, facility, or institution, or part thereof, whether incorporated or not, public or private, that has its own functions and administration.

outlier: Measurements that are unusually large or small relative to the rest and therefore are suspected of misrepresenting the population from which they were collected.
p: The probability that a random measurement from the survey unit is less than Δ.

p’: The probability that the sum of two independent random measurements from the survey unit is less than .

PA: Preliminary Assessment.

PAH: Polycyclic Aromatic Hydrocarbon.

pair production: The interaction of a gamma ray photon with the nucleus of an atom, in which the photon is absorbed and its energy, E > 1.02 MeV, is transformed into an electronpositron pair.

pathway: A mechanism or route by which a contaminant can reach, or be made to affect, a receptor.

PCB: Polychlorinated Biphenyl.

PCE: Tetrachloroethene.

peer review: A documented critical review of work generally beyond the state of the art or characterized by the existence of potential uncertainty. The peer review is conducted by qualified individuals (or organization) who are independent of those who performed the work, but are collectively equivalent in technical expertise (i.e., peers) to those who performed the original work. The peer review is conducted to ensure that activities are technically adequate, competently performed, properly documented, and satisfy established technical and quality requirements. The peer review is an in-depth assessment of the assumptions, calculations, extrapolations, alternate interpretations, methodology, acceptance criteria, and conclusions pertaining to specific work and of the documentation that supports them. Peer reviews provide an evaluation of a subject where quantitative methods of analysis or measures of success are unavailable or undefined, such as in research and development.

people: Those individuals that could be affected by contaminated land. People are distinguished from environment following health and safety and radiological protection convention. Separate consideration may be given to ‘workers’ (who receive a direct financial benefit from the owner/operator) and the public (who do not). Consideration should also be given to people at present and in the future.

performance evaluation: A type of audit in which the quantitative data generated in a measurement system are obtained independently and compared with routinely obtained data to evaluate the proficiency of an analyst or laboratory.

permeability: The relative ease with which a porous medium can transmit a fluid under a hydraulic gradient.

pH: Negative 10log of H+-concentration; a unit of measure for acidity/alkalinity.

photo-effect: The interaction of an photon with an orbital electron of an atom, in which the photon is absorbed and its energy is used for the release of the orbital electron (kinetic energy).

photomultiplier tube: An evacuated glass tube consisting of an anode, cathode, and a series of dynodes that amplifies the detection of a photon. Radiation hits the photocathode; normally, due to the photoelectric effect (in which electrons are emitted from metal when hit with incident electromagnetic radiation) many electrons would be emitted and collected at an anode for the purposes of amplifying the original signal. In a PMT, electrons are deflected toward a series of dynodes that are maintained at a positive potential before finally hitting the terminal anode. Typically, the original photon is amplified by 5 to 7 orders of magnitude and is collected at the anode.

photo-peak: A local maximum in the gamma energy spectrum, representing the emission energy of photons of a source.

PHWR: Pressurised Heavy Water Reactor.

physical probe area: The physical surface area assessed by a detector. The physical probe area is used to make probe area corrections in the activity calculations.

phyto-remediation: The use of plants to remove contaminants from the subsurface into a harvestable biomass.

PID: Photoionization Detector.

Pitman efficiency: A measure of performance for statistical tests. It is equal to the reciprocal of the ratio of the sample sizes required by each of two tests to achieve the same power, as these sample sizes become large.

plume: The spatial distribution of a release of airborne or waterborne material as it disperses in the environment.

PMT: Photo-Multiplier Tube.

point radiation source: A radiation source of limited dimensions.

pollutant linkage: The relationship of a contaminant, a pathway and a receptor.

polypropylene core liner: A deflated ribbon-like liner that can be inserted into a borehole and then pressurized to allow contact with the surface of the hole. A dye impregnated in the liner changes color when it comes in contact with the substance under investigation, for example, DNAPLs. The liner can be pulled from the hole inside out for determination of the zones that contain the contaminant.

portable gamma ray spectrometer: A hand-held instrument for detecting and analysing gamma ray emissions.

power (1-β): The probability of rejecting the null hypothesis when it is false. The power is equal to one minus the Type II error rate, i.e. (1-β).

PPE: personal protective equipment.

ppm: parts per million.

Pr: The probability that a measurement performed at a random location in the survey unit is greater than a measurement performed at a random location in the reference area.

practices: A human activity that can increase the exposure of individuals to radiation from an artificial source, or from a natural radiation source where natural radionuclides are processed for their radioactive, fissile or fertile properties, except in the case of emergency exposure. This is a Basic Safety Standard Directive definition.

precipitation: A standard chemical method that can be used in the treatment of liquid wastes where radionuclides are removed from the liquid by either forming or being carried by the insuluble product of a chemical reaction made to occur within the liquid.

precision: A measure of mutual agreement among individual measurements of the same property, usually under prescribed similar conditions, expressed generally in terms of the standard deviation.

preferred option: The option that is identified by an owner/operator as their preferred one following a comprehensive, systematic and consultative assessment in which all the envisageable options are considered.

preferred strategy: The strategy that is identified by an owner/operator as their preferred one following a comprehensive, systematic and consultative assessment of potential strategies derived by considering the options for the various areas on a site.

pregnant: Said of metal bearing leach solutions after contact with the ore.

PRG: preliminary remediation goal.

Primordial radionuclides: Radionuclides produced during the initial formation of the earth. Those of the radionuclides that remain have very long half-lives

problem definition: Step 1 in the process of moving from site characterization through remediation and closure with a focus on the determination of whether excessive risk exists and the determination of the nature and extent of the contamination leading to the excess risk.

process: A combination of people, machine and equipment, methods, and the environment in which they operate to produce a given product or service.

professional judgement: An expression of opinion, based on technical knowledge and professional experience, assumptions, algorithms, and definitions, as stated by an expert in response to technical problems.

profile maps: Graphic representation of traverse data as a plot with time or distance along the abscissa.

proposed option: The option that is formally submitted by an owner/operator to regulators and decision-makers for approval to implement, following the comparison of options, identification of a preferred option, and consideration of this preferred option in regulatory and other acceptance procedures.

proposed strategy: The strategy that is formally submitted by an owner/operator to regulators and decision-makers for approval to implement, following the comparison of strategies, identification of a preferred strategy, and consideration of this preferred strategy in regulatory and other acceptance procedures.

proton: Principle particle of an atom nucleus. The proton is a positively charged nucleon.
proton number: The number of positively charged nucleons (protons) in the nucleus of an atom.

PSA: Preliminary Site Assessment.

Pu: plutonium.

putrescible waste: Organic waste that may decompose or rot.

PVC: Polyvinyl Chloride.

PWR: Pressurised Water Reactor.

QA/QC: See quality assurance /quality control.

qualified data: Any data that have been modified or adjusted as part of statistical or mathematical evaluation, data validation, or data verification operations.

quality: The totality of features and characteristics of a product or service that bear on its ability to meet the stated or implied needs and expectations of the user.

Quality Assurance (QA): An integrated system of management activities involving planning, implementation, assessment, reporting, and quality improvement to ensure that a process, item, or service is of the type and quality needed and expected by the customer.

Quality Assurance Project Plan (QAPP): A formal document describing in comprehensive detail the necessary QA, QC, and other technical activities that must be implemented to ensure that the results of the work performed will satisfy the stated performance criteria. A Quality Assurance Project Plan describes policy, organization, and functional activities and the Data Quality Objectives and measures necessary to achieve adequate data for use in selecting the appropriate remedy. The QAPP is a plan that provides a process for obtaining data of sufficient quality and quantity to satisfy data needs. It is a part of the Sampling and Analysis Plan.

quality assurance/quality control: The process by which a laboratory can determine the accuracy and precision of sample analysis techniques and analytical results.

Quality Control (QC): The overall system of technical activities that measure the attributes and performance of a process, item, or service against defined standards to verify that they meet the stated requirements established by the customer, operational techniques and activities that are used to fulfil requirements for quality.

quality factor: A factor applied to the absorbed dose in tissue to take account of the different levels of harm inflicted by different types of radioactive decay. Used to calculate equivalent dose.

quality indicators: Measurable attributes of the attainment of the necessary quality for a particular environmental decision. Indicators of quality include precision, bias, completeness, representativeness, reproducibility, comparability, and statistical confidence.

Quality Management Plan (QMP): A formal document that describes the quality system in terms of the organizational structure, functional responsibilities of management and staff, lines of authority, and required interfaces for those planning, implementing, and assessing all activities conducted.

quality system: A structured and documented management system describing the policies, objectives, principles, organizational authority, responsibilities, accountability, and implementation plan of an organization for ensuring quality in its work processes, products (items), and services. The quality system provides the framework for planning, implementing, and assessing work performed by the organization and for carrying out required QA and QC.

R: The rate of missing or unusable measurements expected to occur for samples collected in reference areas or survey units. See missing or unusable data. See nf (Not to be confused with the symbol for the radiation exposure unit Roentgen.)

R&D: Research and Development.

RA: The acceptable level of risk associated with not detecting an area of elevated activity of area _Amin.

226Ra: radium-226.

228Ra: radium-228.

radiation: A flux of particles or energy originating at transitions of unstable atoms. A physical property of some sources.

radiation flux: See radiation.

Radiation Protection Adviser (RPA): An appointment required under some national regulations for all companies involved in work with ionising radiations. The RPA is registered with the HSE and provides advice on all aspects of radiological protection. The RPA will set dose constraints on workers and specify hold points for use during the work.

Radiation Protection Supervisor (RPS): An appointment required under some national regulations for all companies involved in work with ionising radiations. An RPS must have received training related to radiological protection and ensures that the specified safety restrictions are observed.

radiation survey: Measurements of radiation levels associated with a site together with appropriate documentation and data evaluation.

radioactive decay: The spontaneous transformation of an unstable atom into one or more different nuclides accompanied by either the emission of energy and/or particles from the nucleus, nuclear capture or ejection of orbital electrons, or fission. Unstable atoms decay into a more stable state, eventually reaching a form that does not decay further or has a very long half-life.

radioactive halos: In mineralogy and petrology, micro-areas around radioactive minerals, identifiable in rock thin sections, formed by radiation – particularly alpha radiation.

radioactive material: Often used to describe any material containing radionuclides.

radioactive minerals: Rock minerals containing natural radioactive elements.

radioactively contaminated land: Any land in, on or under (including groundwater) which there are radioactive contaminants above natural and artificial background levels that are typical of the area of the country in which the site is located.

radioactivity: The mean number of nuclear transformations occurring in a given quantity of radioactive material per unit time. The International System (SI) unit of radioactivity is the Becquerel (Bq).

radioelements: A proxy term for measured K, U and Th in gamma ray surveys for geological purposes.

radiological survey: Measurements of radiation levels and radioactivity associated with a site together with appropriate documentation and data evaluation.

radio-luminescence: Light produced by the absorption of energy from ionizing radiation.

radiometric instrument: A measuring device having the capacity for detecting radiation.

radio-nuclide: An unstable nuclide that undergoes radioactive decay.

radon: A noble gas, having radioactive isotopes 222Rn, 220Rn, 219Rn (radon, thoron and actinon).

radon background: The component of background gamma radiation originating in disintegration and gamma radiation of short lived decay products of 222Rn in air, particularly 214Pb and 214Bi.

random error: The deviation of an observed value from the true value is called the error of observation. If the error of observation behaves like a random variable (i.e., its value occurs as though chosen at random from a probability distribution of such errors) it is called a random error. See systematic error.

range: The concentration levels in samples over which useful measurements can be made. It is limited at the low end by the detection limit and at the high end by detector saturation.

RBE: Relative Biological Effectiveness.

RDX: Cyclotrimethylenetrinitramine (explosive).

reactive barrier: Groundwater permeable geochemical barriers installed across the flow path of the contaminant plume allowing it to flow through while at the same time removing the contaminant (e.g. radioactive species) through interactions with the reactive component of the barrier.

readily removable: A qualitative statement of the extent to which a radionuclide can be removed from a surface or medium using non-destructive, common, housekeeping techniques (e.g., washing with moderate amounts of detergent and water) that do not generate large volumes of radioactive waste requiring subsequent disposal or produce chemical wastes that are expected to adversely affect public health or the environment.

real-time instrumentation: Sampling technologies that allow the collection of data in the field with the immediate return of results. This allows investigators to scan a site in order to map areas of contamination and the extent of contamination.

receptor: An entity (persons, living organisms, ecological systems, controlled waters, atmosphere, structures, utilities) that may be adversely affected by a contaminant.

records: Information including details of site characterisation work, the process of deciding on the land management option/strategy, implementing the option/strategy and validating its implementation, as well as interaction with stakeholders throughout the process. There is a key principle about the keeping of records.

reference area: Geographical area from which representative reference measurements are performed for comparison with measurements performed in specific survey units at remediation site. A site radiological reference area (background area) is defined as an area that has similar physical, chemical, radiological, and biological characteristics as the site area being remediated, but which has not been contaminated by site activities. The distribution and concentration of background radiation in the reference area should be the same as that which would be expected on the site if that site had never been contaminated. More than one reference area may be necessary for valid comparisons if a site exhibits considerable physical, chemical, radiological, or biological variability.

reference coordinate system: A grid of intersecting lines referenced to a fixed site location or benchmark. Typically the lines are arranged in a perpendicular pattern dividing the survey location into squares or blocks of equal areas. Other patterns include three-dimensional and polar coordinate systems.

reference radionuclide: A gamma ray emitting radionuclide used for instrument energy calibration or instrument sensitivity checks.

reference region: The geographical region from which reference areas will be selected for comparison with survey units.

regulation: A rule, law, order, or direction from federal or state governments regulating action or conduct. As example: Regulations concerning radioisotopes in the environment in the United States are shared by the Environmental Protection Agency (EPA), the U.S. Nuclear Regulatory Commission (NRC), the U.S. Department of Energy (DOE), and many State governments. Federal regulations and certain directives issued by the U.S. Department of Defense(DOD) are enforced within the DOD.

relative shift (Δ/σ): Δ divided by σ, the standard deviation of the measurements. See delta.

relative standard deviation: See coefficient of variation.

relaxation mass, β (g/cm2): A parameter specifying the vertical distribution of gamma emitting radionuclide in the ground, controlling the surface gamma activity.

release criterion: A regulatory limit expressed in terms of dose or risk.

rem (radiation equivalent man): The conventional unit of dose equivalent. The corresponding International System (SI) unit is the Sievert (Sv): 1 Sv = 100 rem.

remedial action: Those actions that are consistent with a permanent remedy taken instead of, or in addition to, removal action in the event of a release or threatened release of a hazardous substance into the environment, to prevent or minimize the release of hazardous substances so that they do not migrate to cause substantial danger to present or future public health or welfare or the environment. See remedy.

remediation: Measures taken, including stabilization or isolation of the contamination in situ, to reduce human exposure or environmental damage from already contaminated land or water.

remediation control survey: A type of survey that includes monitoring the progress of remedial action by real time measurement of areas being decontaminated to determine whether or not efforts are effective and to guide further decontamination activities.

remediation of contaminated land: The taking of any actions to reduce the risks to humans or other organisms from contamination in, on or under land (including the groundwater).

remedy: See remedial action.

removable activity: Surface activity that is readily removable by wiping the surface with moderate pressure and can be assessed with standard radiation detectors. It is usually expressed in units of dpm/100 cm2.

removal: The cleanup or removal of released hazardous substances, or pollutants or contaminants which may present an imminent and substantial danger; such actions as may be necessary taken in the event of the threat of release of hazardous substances into the environment; such actions as may be necessary to monitor, assess, and evaluate the threat of release of hazardous substances; the removal and disposal of material, or the taking of other such actions as may be necessary to prevent, minimize or mitigate damage to the public health or welfare or the environment.

replicate: A repeated analysis of the same sample or repeated measurement at the same location.

representative measurement: A measurement that is selected using a procedure in such a way that it, in combination with other representative measurements, will give an accurate representation of the phenomenon being studied.

representativeness: A measure of the degree to which data accurately and precisely represent a characteristic of a population, parameter variations at a sampling point, a process condition, or an environmental condition.

reproducibility: The precision, usually expressed as a standard deviation, that measures the variability among the results of measurement of the same sample at different laboratories.

residual radioactivity: Radioactivity in structures, materials, soils, groundwater, and other media at a site resulting from activities under the cognizant organization’s control. This includes radioactivity from all sources used by the cognizant organization, but excludes background radioactivity as specified by the applicable regulation or standard. It also includes radioactive materials remaining at the site as a result of routine or accidental releases of radioactive material at the site and previous burials at the site, even if those burials were made in accordance with the provisions in national laws.

restoration: Measures taken to return the environment in to approximately the same state in which it previously existed or to a state that is in agreement with future land use scenarios and all publically accepted agreements.

restricted use: A designation following remediation requiring radiological controls.

risk: An assessment of the potential for harm or damage posed by a contaminant or circumstance taking account of the likelihood, or probability, of occurrence. Risk is the product of hazard and probability.

risk assessment: A systematic process that establishes the existence, nature and significance of risk. Different methods are used to evaluate different types of risks. The approach to assessing risks to people’s health and to the environment from non-radioactive contamination is largely described in regulatory guidance. The approach to assessing risks to people and the environment from radioactive contamination is different and an approach is outlined in the guidance.

RMBK: Light Water Cooled Graphite Moderated Reactor (Reaktor Bolschoi Moschtschnosti Kanalny).

222Rn: radon-222.

robust: A statistical test or method that is approximately valid under a wide range of conditions.

roentgen, R: Unit of exposure, equal to 2.58 × 10-4 C/kg.

ROI: Region Of Interest.

RoT: Rules of Thumb.

RPA: Radiation Protection Advisor

RPE: Respiratory Protective Equipment.

RSS: Radiation Scanning System.

run chart: A chart used to visually represent data. Run charts are used to monitor a process to see whether or not the long range average is changing. Run charts are points plotted on a graph in the order in which they become available, such as parameters plotted versus time.

s: second.

s: The arithmetic standard deviation of the mean.

S+: The test statistic used for the Sign test.

SAFEGROUNDS: Safety and Environmental Guidance for Remediation of UK Nuclear and Defence Sites.

safety case: Documentation for a nuclear installation that demonstrates safety. Safety cases must be produced and maintained during the design, construction, manufacture, commissioning, operation and decommissioning of the installation.

sample: (As used in EURSSEM) A part or selection from a medium located in a survey unit or reference area that represents the quality or quantity of a given parameter or nature of the whole area or unit; a portion serving as a specimen.

sample: (As used in statistics) A set of individual samples or measurements drawn from a population whose properties are studied to gain information about the entire population.
sampling: Methods and techniques used to obtain a representative sample of the material under investigation.

sampling and analysis plan: A plan that provide a process for obtaining data of sufficient quality and quantity to satisfy data needs. The sampling and analysis plans consists of two parts: 1) the Field Sampling Plan, which describes the number, type, and location of samples and the type of analyses; and 2) the Quality Assurance Project Plan, which describes policy, organization, functional activities, the Data Quality Objectives, and measures necessary to achieve adequate data for use in selecting the appropriate remedy.

sampling error: Error resulting from the collection or storage of samples.

SAP: Safety Assessment Principles

scanning: An evaluation technique performed by moving a detection device over a surface at a specified speed and distance above the surface to detect radiation.

scintillation counter: A sensor converting the energy photons or particles of nuclear radiation to voltage pulses, based on luminescence of scintillation matter.

scintillation detector: Radiation detector relying on the property of certain materials to fluoresce when ionised by radiation. The light produced is measured using a photomultiplier.

scintillation type crystals (NaI crystals): When hit by high-energy gamma rays, these crystals produce charged particles and give off low-energy photons that are collected by a photomultiplier tube. These crystals are a component of a device used in the real-time detection of radioactive constituents at remedial sites.

scoping survey: A type of survey that is conducted to identify: 1) radionuclide contaminants, 2) relative radionuclide ratios, and 3) general levels and extent of contamination.
secular equilibrium: Relationship in a parent/progeny radionuclide system where the half-life of the parent is much longer than that of the progeny; with time, the radioactivity of the parent becomes equal to that of the progeny within the series (e.g., radium-226 to radium-222).

self-assessment: Assessments of work conducted by individuals, groups, or organizations directly responsible for overseeing and/or performing the work.

semi-conductor counter: A sensor converting the energy photons or particles of nuclear radiation to voltage pulses, based on induced conductivity in a part of a semiconductor by radiation.

semiconductor-type crystals (e.g. HPGe crystals): Crystals that are composed of an element with four available electrons, such as those in column IVa of the periodic table, with an introduced impurity. Elements like carbon and germanium can form four covalent bonds with neighbouring like atoms to form a crystal structure. When an impurity element with either three or five available electrons is introduced, the extra or missing electron allows for the creation of electron-hole pairs that offer partial resistance to electricity.

sensitivity: The efficiency of the detector response to radionuclide concentration.it is the slope of the detector signal.

shape parameter (S): For an elliptical area of elevated activity, the ratio of the semi-minor axis length to the semi-major axis length. For a circle, the shape parameter is one. A small shape parameter corresponds to a flat ellipse.

shift: See delta (Δ).

shine: Radiation originating from sources other than the material directly under a detector. Shine is of concern in remedial surveys because it can bias results.

Sievert (Sv): The special name for the International System (SI) unit of dose equivalent. 1 Sv = 100 rem = 1 Joule per kilogram.

Sign test: A nonparametric statistical test used to demonstrate compliance with the release criterion when the radionuclide of interest is not present in background and the distribution of data is not symmetric. See also Wilcoxon Rank Sum test.

single-blind measurement: A measurement that can be distinguished from routine measurements but are of unknown concentration. See non-blind measurement and double-blind measurement.

site: Any installation, facility, or discrete, physically separate parcel of land, or any building or structure or portion thereof, that is being considered for survey and investigation.

site reconnaissance: A visit to the site to gather sufficient information to support a site decision regarding the need for further action, or to verify existing site data. Site reconnaissance is not a study of the full extent of contamination at a facility or site, or a risk assessment.
size (of a test): See alpha.

snow-water equivalent: A term describing the thickness of a snow or water absorbing layer having the same attenuation of gamma rays of the specified energy.

soil: The top layer of the earth’s surface, consisting of rock and mineral particles mixed with organic matter. A particular kind of earth or ground – e.g., sandy soil.

soil activity (soil concentration): The level of radioactivity present in soil and expressed in units of activity per soil mass (typically Bq/kg or pCi/g).

soil corings: A soil sample obtained by driving a hollow tube into the ground. The tube is removed along with a narrow soil sample that reflects the soil profile and, if present, contamination with depth.

sorption: A broad term referring to the interaction of an atom, molecule or particle within pores or on the surfaces of a solid, the ‘substrate’. Absorption is generally used to refer to interactions taking place largely within the pores of solids, in which case the absorption capacity of the solid is proportional to its volume. Adsorption refers to interactions taking place on solid surfaces, so that the capacity of a substrate is proportional to the effective specific surface area. Chemisorption refers to actual chemical bonding with the substrate. Physisolption refers to physical attraction, e.g. by weak electrostatic forces.
source: A contaminant which is in, on or under the land and which has the potential to cause harm to an identified receptor or to cause pollution of controlled waters.

source-detector geometry: Description of mutual geometric relationship between the detector of an instrument and a source of radiation, involving distance, spatial angle of source radiation and source shape and dimensions.

source term: All residual radioactivity remaining at the site, including material released during normal operations, inadvertent releases, or accidents.

spatial uncertainty: Error in a sampling plan associated with the incomplete coverage of a contaminated area.

specific activity: A measure of activity of a unit mass, expressed in Becquerel per kilogram.

spectrum drift: Phenomenon caused by non-linearity between pulse amplitudes at the detector output and energy of impacting particles into the detector, at very high count rates.

split: A sample that has been homogenized and divided into two or more aliquots for subsequent analysis.

90Sr: Strontium-90.

stakeholder: A person or organisation that has an interest in the management of the contaminated land. There are various groups of stakeholders: institutional stakeholders include the owner/operator, regulators, government departments and local authorities. External stakeholders are all those outside the owner/operator organisation. Those stakeholders involved in decisions on the management of contaminated land are participating stakeholders and may include local residents, CBOs and NGOs.

standard: A reference radiation source of known radioelement composition, concentration or activity, with a defined shape, dimensions and matrix composition.

standard normal distribution: A normal (Gaussian) distribution with mean zero and variance one.

standard operating procedure (SOP): A written document that details the method for an operation, analysis, or action with thoroughly prescribed techniques and steps, and that is officially approved as the method for performing certain routine or repetitive tasks.
standardization the data: The reprocessing of gamma ray data to the correct level and correct units.

statistical control: The condition describing a process from which all special causes have been removed, evidenced on control chart by the absence of points beyond the control limits and by the absence of non-random patterns or trends within the control limits. A special cause is a source of variation that is intermittent, unpredictable, or unstable.

strategy: A broad plan for the management of all the contaminated land on a site, probably comprising of several options.

stratification: The act or result of separating an area into two or more sub-areas so as each sub-area has relatively homogeneous characteristics such as contamination level, topology, surface soil type, vegetation cover, etc.

stripping correction: The correction applied to an elemental window count rate to correct for interference from gamma rays due to other elements in that window.

stripping ratios: Numerical parameters, defined by ratios of gamma ray spectrometer sensitivities, applied in the stripping method.

subsurface soil sample: A soil sample that reflects the modelling assumptions used to develop the DCGL for subsurface soil activity.

supervised area: Any area where the annual effective dose to persons working there is likely to exceed 1 mSv or one-tenth of the appropriate dose limit.

surface contamination: Residual radioactivity found on building or equipment surfaces and expressed in units of activity per surface area (Bq/m2 or dpm/100 cm2).

surface soil sample: A soil sample that reflects the modelling assumptions used to develop the DCGL for surface soil activity.

surveillance (quality): Continual or frequent monitoring and verification of the status of an entity and the analysis of records to ensure that specified requirements are being fulfilled.

survey: A systematic evaluation and documentation of radiological measurements with a correctly calibrated instrument or instruments that meet the sensitivity required by the objective of the evaluation.

survey plan: A plan for determining the radiological characteristics of a site.

survey unit: A geographical area consisting of structures or land areas of specified size and shape at a remediated site for which a separate decision will be made whether the unit attains the site-specific reference-based cleanup standard for the designated pollution parameter. Survey units are generally formed by grouping contiguous site areas with a similar use history and the same classification of contamination potential. Survey units are established to facilitate the survey process and the statistical analysis of survey data.

Sv: Sievert, a unit of dose from ionising radiation.

SVOC: Semivolatile Organic Compounds.

systematic error: An error of observation based on system faults which are biased in one or more ways, e.g., tending to be on one side of the true value more than the other.

T+: The test statistic for the Wilcoxon Signed Rank test.

tandem testing: Two or more statistical tests conducted using the same data set.

TCA: Trichloroethane.

TCE: Trichloroethylene (a solvent).

technical review: A documented critical review of work that has been performed within the state of the art. The review is accomplished by one or more qualified reviewers who are independent of those who performed the work, but are collectively equivalent in technical expertise to those who performed the original work. The review is an in-depth analysis and evaluation of documents, activities, material, data, or items that require technical verification or validation for applicability, correctness, adequacy, completeness, and assurance that established requirements are satisfied.

technical systems audit (TSA): A thorough, systematic, on-site, qualitative audit of facilities, equipment, personnel, training, procedures, recordkeeping, data validation, data management, and reporting aspects of a system.

TEDE (total effective dose equivalent): The sum of the effective dose equivalent (for external exposure) and the committed effective dose equivalent (for internal exposure). TEDE is expressed in units of Sv or rem. See CEDE.

TENORM: Technologically Enhanced Natural Occuring Radioactive Material

ternary maps: K, U, Th three component colour presentation of natural radioelement concentration in the ground.

terrestrial radiation: Radiation originating from natural radionuclides in the ground.

test statistic: A function of the measurements (or their ranks) that has a known distribution if the null hypothesis is true. This is compared to the critical level to determine if the null hypothesis should be

test-line: A selected airborne traverse used for daily and temporal control of instrument function and stability of environmental radiation.

230Th: thorium-230.

232Th: thorium-232.

transfer factor: a factor for a radionuclide between different environmental compartments, for example soil and plants. Unit depends on the original (activity) concentration units for the respective compartments.

thermal energy of the Earth: Thermal energy of the Earth is mainly generated by the disintegration of natural radionuclides in the Earth. Thermal energy can be described by the heat production (μW/m3) of unit rock volume, or by heat flow (mW/m2).

threshold gamma ray spectrometer: Radiometric instrument selecting and registering gamma rays of energy exceeding an energy discrimination threshold.

tied measurements: Two or more measurements that have the same value.

tie-line: Airborne profiles, generally flown perpendicular to regular survey lines – used to level regular survey line data.

topographical survey: A survey of the physical features of a site in three dimensions.

ToR: Terms of Reference.

toxic: Waste and material that contain certain substances determined to be harmful to human health in very small concentrations

TPA: Tri-Party Agreement.

TPP: Technical Project Planning.

traceability: The ability to trace the history, application, or location of an entity by means of recorded identifications. In a calibration sense, traceability relates measuring equipment to national or international standards, primary standards, basic physical constants or properties, or reference materials. In a data collection sense, it relates calculations and data generated throughput the project back to the requirements for quality for the project.

Triad: The U.S. Environmental Protection Agency’s environmental data collection design program consisting of three primary components: 1) systematic project planning, 2) dynamic work plan strategies, and 3) the use of real-time data.

triangular sampling grid: A grid of sampling locations that is arranged in a triangular pattern. See grid.

TRU: transuranic.

two-sample t test: A parametric statistical test used in place of the Wilcoxon Rank Sum (WRS) test if the reference area and survey unit measurements are known to be normally (Gaussian) distributed and there are no less-than measurements in either data set.

Type I decision error: A decision error that occurs when the null hypothesis is rejected when it is true. The probability of making a Type I decision error is called alpha (α).

Type II decision error: A decision error that occurs when the null hypothesis is accepted when it is false. The probability of making a Type II decision error is called beta (β).

238U: uranium-238.

UNGG: Untreated Natural Uranium Graphite Gas Cooled Reactor.

unity rule (mixture rule): A rule applied when more than one radionuclide is present at a concentration that is distinguishable from background and where a single concentration comparison does not apply. In this case, the mixture of radio-nuclides is compared against default concentrations by applying the unity rule. This is accomplished by determining: 1) the ratio between the concentration of each radionuclide in the mixture, and 2) the concentration for that radionuclide in an appropriate listing of default values. The sum of the ratios for all radio-nuclides in the mixture should not exceed 1.

unrestricted area: Any area where access is not controlled by a licensee for purposes of protection of individuals from exposure to radiation and radioactive materials – including areas used for residential purposes.

unrestricted release: Release of a site from regulatory control without requirements for future radiological restrictions. Also known as unrestricted use.

uranium equivalent: The amount of uranium that will give the same measured gamma radiation as a particular radionuclide; for example: uranium equivalent of potassium (ppm U/1% K), uranium equivalent of thorium (ppm U/1ppm Th).

UXO: Unexploded ordnance.

V: volt.

vadose zone: Subsurface zone extending from the surface to the top of the capillary fringe overlying the groundwater.

validation: Confirmation by examination and provision of objective evidence that the particular requirements for a specific intended use are fulfilled. In design and development, validation concerns the process of examining a product or result to determine conformance to user needs.

verification: Confirmation by examination and provision of objective evidence that the specified requirements have been fulfilled. In design and development, verification concerns the process of examining a result of given activity to determine conformance to the stated requirements for that activity.

VLLW: Very Low Level (radioactive) Waste.

VOC: Volatile organic compound.

WAC: waste acceptance criterion.

waste acceptance criteria (WAC): Level of contamination set by a waste disposal facility that defines the type of waste it will accept.

weighting factor (Wt): The fraction of the overall health risk, resulting from uniform, whole-body radiation, attributable to specific tissue. The dose equivalent to tissue is multiplied by the appropriate weighting factor to obtain the effective dose equivalent to the tissue.
whole body dose: See effective dose.

Wilcoxon Rank Sum (WRS) test: A nonparametric statistical test used to determine compliance with the release criterion when the radionuclide of concern is present in background. See also Sign test.

working level: A special unit of radon exposure defined as any combination of short-lived radon daughters in 1 litre of air that will result in the ultimate emission of 1.3×105 MeV of potential alpha energy. This value is approximately equal to the alpha energy released from the decay of progeny in equilibrium with 100 pCi of 222Ra.

Wr: The sum of the ranks of the adjusted measurements from the reference area, used as the test statistic for the Wilcoxon Rank Sum test.

Ws: The sum of the ranks of the measurements from the survey unit, used with the Wilcoxon Rank Sum test.

Xrays: Electromagnetic radiation of low energy (E > 40 keV, approximately).

XRF: x-ray fluorescence.

yd2: square yard.

Z1-φ: The value from the standard normal distribution that cuts off 100 φ % of the upper tail of the standard normal distribution. See standard normal distribution.