List of acronyms


Internal and external links are provided where appropriate.


ACPSR: Advisory Committee of Project Safety Review

AERB: Atomic Energy Regulatory Body

AFCN: Agence fédérale de contrôle nucléaire (Federal Agency for Nuclear Control, Belgium)

ALARA: As low as reasonably achievable. Making every reasonable effort to minimise exposure to ionising radiation as far below regulatory or legal dose limits with economic and social considerations taken into account.

ALCYONE: Computer code for fuel behaviour

ANDRA: Agence nationale pour la gestion des déchets radioactifs (National Agency for Radioactive Waste Management, France)

ANL: Argonne National Laboratory

ANSTO: Australian Nuclear Science and Technology Organisation

ASME: American Society of Mechanical Engineers

ASN: Autorité de sûreté nucléaire (Nuclear Safety Authority, France)

ATHLET: Analysis of thermal-hydraulics of leaks and transients

AUDR: Soviet All-Union Dose Registry

AVN: Association vinçotte nucléaire (Belgium)


BARC: Bhabha Atomic Research Centre

BART: Best-estimate analysis of reflood transients' computer code

BDBA: Beyond-design-basis accident

BfS: Bundes Schweizerischer Frauenvereine

BMU: Das Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Germany)

BOL: Beginning of life

BP: Break preclusion

BSC: 1963 Brussels Convention Supplementary to the Paris Convention, as amended.

BSS: Basic Safety Standards.

BWR: Boiling water reactor. A very common type of light water reactor in use worldwide. Ordinary water, used as both coolant and moderator, is allowed to boil in the reactor core. The steam produced is then used to directly generate electricity.


CAM: Continuous air monitor

CANDU: Canadian deuterium uranium reactor (PHWR type). This type of reactor uses "heavy" water, i.e. deuterium oxide, as the coolant and moderator. The use of heavy water permits the use of natural uranium as the reactor fuel eliminating the need for enrichment of the uranium.

CCF: Common-cause failure
NEA joint project on CCF events:

CEA: Commissariat à l'énergie nucléaire (Atomic Energy Commission, France)

CERN: European Organization for Nuclear Research/Organisation européenne pour la recherche nucléaire (Switzerland). It was originally the Conseil européen pour la recherche nucléaire

CCS: Carbon capture and storage

CINDA: Computer Index of Nuclear Data. Online database.

CMR: Central monitoring room

CNRA: NEA Committee on Nuclear Regulatory Activities

CNRS: Centre national de la recherche scientifique (National Center for Scientific Research, France).

CNSC: Canadian Nuclear Safety Commission

CNSNS: Comisión Nacional de Seguridad Nuclear y Salvaguardias (National Commission on Nuclear Safety and Safeguards, Mexico).

COMPSIS: Computer-based Systems Important to Safety. NEA joint project.

CoRWM: Committee on Radioactive Waste Management (United Kingdom)

CP-ECR: Cathcart & Pawel correlation for ECR prediction

CPPC: Contracting Parties to the 1960 Paris Convention on Third Party Liability in the Field of Nuclear Energy, as amended.

CPD: International Co-operative Programme for the Exchange of Scientific and Technical Information Concerning Nuclear Installation Decommissioning Projects. An NEA joint project.

CRPPH: NEA Committee on Radiation Protection and Public Health

CSC: Convention on Supplementary Compensation for Nuclear Damage

CSN: Consejo de Seguridad Nuclear (Nuclear Safety Council, Spain)

CSO: Civil Society Organisation

CSS: Commission on Safety Standards (IAEA)

CSNI: NEA Committee on the Safety of Nuclear Installations

CT: Computerised tomography

CTBT: Comprehensive nuclear test ban treaty


DAC: Design acceptance confirmation

DBA: Design basis accident

DCH: Direct containment heating
NEA report on the subject (1996)

DCEG: Decommissioning Cost Estimation Group

DICE: Database for the International Handbook of Evaluated Criticality Safety Benchmark Experiments. NEA database. and

DIDELSYS: Task Group on Defence in Depth of Electrical Systems and Grid Interaction

DNA: Desoxyribonucleic acid

DOE: Department of Energy (United States)

DRACCAR: Déformation et renoyage d'un assemblage de crayons combustiblespendant un accident de refroidissement computer code


EAF: European Activation Files (part of the JEFF data library project)
Websites: and

EC: European Commission

ECCS: Emergency core cooling system

ECR: Equivalent cladding reacted

EDG: Emergency diesel generator

EDGAR: Experimental facility for fuel-rod behaviour during LOCA

EFF: European Fusion Files (part of the JEFF data library project)

EGCO: NEA Expert Group on the CRPPH Collective Opinion

EGOE: NEA Expert Group on Occupational Exposure

EGIR: NEA Expert Group on the Implications of ICRP Recommendations

EGIS: NEA Expert Group on the Implications of Radiological Protection Science

EGOS: NEA Expert Group on Operational Safety

EGRA: NEA Expert Group on the Regulatory Application of Authorisation

EGSS: NEA Expert Group on Radiological Protection Science at the Service of Stakeholders

EHPG: Enlarged Halden programme group

ENENA: European Nuclear Education Network Association/Réseau Européen pour l’Enseignement des Sciences Nucléaires (France)

ENSDF: Evaluated Nuclear Structure Data File Database (online database)

ENSI: Swiss Federal Nuclear Safety Inspectorate

ENSREG: European Nuclear Safety Regulators' Group

EOL: End of life

EPA: Environmental Protection Agency (United States)

EPMA: Electron-probe micro-analyzer

EPR: A third generation pressurised water reactor, formerly known as Evolutionary Power Reactor, now simply called EPR.

EPRI: Electric Power Research Institute (United States)

ETS: Emissions trading system

EU: European Union

EVA: Evaluated Nuclear Data Retrievals. NEA online database.

EXAFS: Extended x-ray absorption fine structure

EXFOR: Experimental Nuclear Reaction Data Retrievals. Online database.


FALCO: PSI computer code for fuel behaviour

FEBA: Flooding experiments with blocked arrays

FBR: Fast breeder reactor

FAO: United Nations Food and Agriculture Organisation (FAO)

FFRD: Fuel fragmentation, relocation and dispersal

FGR: Fission gas release

FLASH: Experimental programme on fuel behaviour during LOCA

FNPP: NDC Ad hoc Expert Group on the Financing of Nuclear Power Plants

FRAPCON: Steady-state fuel-rod computer code

FRELAX: PSI computer model for thermal behaviour and fuel relocation in the fuel rods

FSC: NEA Forum on Stakeholder Confidence


GAMA: NEA Working Group on Accident Management and Analysis

GDA: Generic design assessment

GEOTRAP: NEA Expert Group on Radionuclide Migration in Geologic Media

GCR: Gas-cooled reactor

GDA: Generic design assessment

GFR: Gas-cooled fast reactor

GIF: Generation IV International Forum. The NEA serves as the technical secretariat for GIF.

GSF: Forschungszentrum für Umwelt und Gesundheit (National Research Center for Environment and Health, Germany)


HAEA: Hungarian Atomic Energy Authority

HBRP: High burn-up rim project

HBS: High burnup structure

HBU: High burnup fuel

HBWR: Halden boiling-water reactor

HEU: Highly-enriched uranium

HLW: High-level waste. Radioactive waste is normally classified into a small number of categories to facilitate regulation of handling, storage and disposal based on the concentration of radioactive material it contains and the time for which it remains radioactive. The definitions of categories differ from country to country. However, in general, HLW contains long-lived radionuclides with high activity, which may also produce heat. It typically is concentrated as part of the process of reprocessing and solidified using vitrification to produce a glass-like substance suitable for interim storage and ultimately, disposal. Spent nuclear fuel that will not be reprocessed is included in this category. Geological disposal is foreseen for this type of waste.

HM: Heavy metal

HLW: High-level waste

HMGU: Helmoholtz Zentrum München (Germany)

HPCI: High pressure coolant injection system

HPRL: High Priority Nuclear Data Request List. NEA online database.

HRP: Halden reactor project

HSK: Hauptabteilung für die Sicherheit der Kernanlagen (Federal Nuclear Safety Inspectorate, Switzerland)

HSE: Health and Safety Executive (United Kingdom)

HTR: High-temperature gas-cooled reactor

HVE: Hot vacuum extraction


IAEA: International Atomic Energy Agency (IAEA)

IARC: International Agency for Research on Cancer (WHO)

ICDE: International Common-cause Data Exchange. NEA joint project.

ICSBEP: NEA International Criticality Safety Benchmark Evaluation Project

ICRP: International Commission on Radiological Protection

IEA: International Energy Agency (IEA)

IFE: Institutt for energiteknikk (Institute for Energy Technology, Norway). Responsible for operations of the OECD Halden Reactor Project.

IFNEC: International Framework For Nuclear Energy Cooperation. The NEA serves as the technical secretariat for IFNEC.

IGSC: Integration Group for the Safety Case (NEA)

ILW: Intermediate-level waste. Radioactive waste is normally classified into a small number of categories to facilitate regulation of handling, storage and disposal based on the concentration of radioactive material it contains and the time for which it remains radioactive. The definitions of categories differ from country to country. However, in general, ILW needs specific shielding during handling and, depending on the specific content of long-lived radionuclides, it may need geological disposal or it may be suitable for surface or near-surface disposal.

INES: International Nuclear Event Scale, introduced by the International Atomic Energy Agency (IAEA) in 1990.

INEX: International Nuclear Emergency Exercises Programme (NEA)

INL: Idaho National Laboratory

INLEX: International Expert Group on Nuclear Liability (IAEA)

INPRO: International Project on Innovative Nuclear Reactors and Fuel Cycles (IAEA)

INRA: International Nuclear Regulators Association

INSAG: International Nuclear Safety Advisory Group

IPAG: NEA Expert Group on Integrated Performance Assessment

IPHECA: International Programme on the Health Effects of the Chernobyl Accident (WHO)

IRPA: International Radiation Protection Association

IRSN: Institut de radioprotection et de sûreté nucléaire /Radiological Protection and Nuclear Safety Institute (France)

ISL: In situ leaching

ISNL: International School of Nuclear Law (NEA)

ISOE: Information System on Occupational Exposure. NEA joint project.

ISPRA: Istituto Superiore per la  Protezione e la Ricerca Ambientale (Italian National Institute for Environmental Protection and Research, Italy)

ITAAC: Inspection, tests, analyses, and acceptance criteria

ITER: International thermonuclear experimental reactor


JAEA: Japan Atomic Energy Agency

JEFF: Joint evaluated fission and fusion project (NEA)

JET: Joint European Torus. A nuclear fusion experiment in Oxforshire, UK.


KAERI: Korea Atomic Energy Research Institute

KEPIC: Korea Electric Power Industry Code

KINS: Korea Institute of Nuclear Safety

KfK: Kernforschungszentrum Karlsruhe (now known as KIT), Germany

KIT: Karlsruhe Institut für Techologie / Karlsruhe Institute of Technology (formerly known as KfK), Germany


LANL: Los Alamos National Laboratory (DOE, United States)

LBB: Leak before break

LBLOCA: Large break LOCA

LCOE: Levelised cost of electricity

LCPD: Large combustion plant directive (2001/80/EC)

LEU: Low-enriched uranium

LFR: Lead-cooled fast reactor

LHGR: Linear heat generation rate

LLW: Low-level waste. Radioactive waste is normally classified into a small number of categories to facilitate regulation of handling, storage and disposal based on the concentration of radioactive material it contains and the time for which it remains radioactive. The definitions of categories differ from country to country. However, in general, LLW is a type of waste that does not need significant shielding for handling and, because of the absence of long-lived radionuclides, is suitable for surface or near-surface disposal. About 90% of the radioactive waste volume produced in the world each year is LLW.

LOCA: Loss-of-coolant accident

LPSI: Low-pressure safety injection system

LTO: Long-term operation

LWR: Light water reactor. A nuclear reactor type that is cooled and/or moderated by ordinary water, as opposed to heavy water.


M&O: Management and operations

MAPRAT: Maximum average power ratio

MATARE: Coupled computer code, MAbel-TAlink-RElap

MCCI: Melt Coolability and Concrete Interaction. NEA joint project.

MDEP: Multinational Design Evaluation Programme. The NEA serves as the technical secretariat for MDEP.

METI: Ministry of Economy, Trade and Industry (Japan)

MEXT: Ministry of Education, Culture, Sports, Science and Technology (Japan)

MIMAS: Micronized masterblend, manufacturing technique

MIR: Modernised international reactor

MOL: Middle of life

MOX: Mixed oxide fuel. A fuel for nuclear power plants that consists of a mixture of depleted uranium oxide and plutonium oxide.

MNEPR: Multilateral Nuclear Environmental Programme in the Russian Federation

MSIP: Ministry of Science and ICT (Korea)

MSR: Molten salt reactor

MW: Megawatt. The international unit of power that is equal to 1x106 watts. A megawatt electric (MWe) refers to the electrical output from a generator. A megawatt thermal (MWth) refers to the heat output from a nuclear reactor. The difference is a measure of the efficiency of the power generation process. Typically, the heat output of a nuclear reactor is three times its electrical output, thus a reactor with a thermal output of 2 700 MW may produce about 900 MW of electricity.


NAGRA: Nationale Genossenschaft für die Lagerung radioaktiver Abfälle / Société coopérative nationale pour le stockage des déchets radioactifs (National Co-operative for the Disposal of Radioactive Waste, Switzerland).

NAZ: Nationale Alarmzentrale (Centrale nationale d'alarme/National Emergency Operations Centre, Switzerland)

NCC: Natural circulation cooling

NCRP: National Committee on Radiation Protection (United States)

NDC: NEA Nuclear Development Committee

NDE: Non-destructive examination

NEA: Nuclear Energy Agency (OECD)

NGNP: Next generation nuclear plant

NGO: Non-governmental organisation

NHDD: Nuclear hydrogen production development and demonstration (Korea)

NLC: NEA Nuclear Law Committee

NPE: Nuclear pressure equipment

NPS: Nuclear power station

NPT: Treaty on the non-proliferation of nuclear weapons

NRA: Nuclear Regulation Authority (Japan)

NRC: Nuclear Regulatory Commission (United States)

NRDC: International Network of Nuclear Reaction Data Centres

NRPA: Statens strålevern (Radiation Protection Authority, Norway)

NSC: NEA Nuclear Science Committee

NSG: Nuclear Suppliers Group. The Nuclear Suppliers Group is a group of nuclear supplier countries, 46 as of October 2006, which work together to prevent the proliferation of nuclear weapons. These countries pursue the aims of the NSG through adherence to consensus guidelines concerning nuclear and nuclear-related exports and through the exchange of information.

NSL: Nuclear site licence

NSR: Nuclear Science References Database. Online database.

NSRR: Nuclear safety research reactor (located at JAEA, Japan)

NSSC: Nuclear Safety and Security Commission (Korea)

NSSG: G8 Nuclear Safety and Security Group

NSSS: Nuclear steam supply system

NUDAT: Nuclear Data Database. Online database.

NUMO: Nuclear Waste Management Organization of Japan

NUSSC: Nuclear Safety Standards Committee (IAEA)


O&M: Operation and maintenance

OCRWM: Office of Civilian Radioactive Waste Management (USA). See the DOE's Office of Nuclear Energy (United States).

OECD: Organisation for Economic Co-operation and Development

ONDRAF/NIRAS: Organisme national des déchets radioactifs et des matières fissiles enrichies/Nationale Einrichtung für radioactive Abfäille und angericherte Spaltmaterialien (Belgian Agency for Radioactive Waste and Enriched Fissile materials).

ONR: Office for Nuclear Regulation (United Kingdom)

OPDE: NEA Piping Failure Data Exchange. NEA joint project.


P&T: Partitioning and transmutation. Partitioning is the separation of undesirable long-lived radioactive elements such as minor actinides (e.g. americium-243) and fission products from spent fuel. Transmutation is the transformation of these undesirable elements into short-lived or stable elements using nuclear reactions. Together these processes would, at least partially, eliminate those parts of high-level waste that contribute most to its heat generation and long-lived radioactivity. P&T therefore has the potential to reduce the time that waste needs to be kept isolated from several thousand to several hundreds of years. NEA work on P&T:

PBF: Power burst facility (at the Idaho National Engineering Laboratory, United States)

PC: 1960 Paris Convention on Third Party Liability in the Field of Nuclear Energy, as amended.

PCMI: Pellet-clad mechanical interaction

PCSR: Preconstruction safety report

PCT: Peak cladding temperature

PDSC: Project design safety committee

PET: Positron emission tomography

PFBR: Prototype fast breeder reactor

PHWR: Pressurised heavy water reactor

PIRT: Phenomena identification and ranking table

PRA: Probabilistic risk assessment

PRISME: Propagation d'un incendie pour des scénarios multi-locaux élémentaires (Fire Propagation in Elementary, Multi-room Scenarios). NEA joint project.

PRWG: Peer Review Working Group of the G8-EU

PSA: Probabilistic safety assessment. A PSA is a type of safety analysis that uses probabilistic risk assessment techniques during both the design and operation of a nuclear power plant to analyse the overall risk. Considering an entire set of potential events with their respective probabilities and consequences, the overall risk of a nuclear incident or accident can be assessed. For a power plant this risk is given in terms of a core melt frequency or the frequency of a large radioactive release. For existing power plants a value below about 1 x 10-4 per year for a core damage probability is generally accepted, while new designs should be even less than 1 x 10-5 per year. The current practice is that the computed results are generally viewed as targets rather than absolute values that would serve for regulatory acceptance or refusal.

PSAR: Preliminary safety analysis report

PSI: Paul Scherrer Institute (Switzerland)

PUREX: Plutonium uranium reduction extraction

PWR: Pressurised water reactor. A nuclear reactor maintained under a high pressure to keep its coolant water from boiling at the high operating temperature. The heat generated by the reactor is transferred from the core to a large heat exchanger that heats water in a secondary circuit to produce the steam needed to generate electricity.


R&D: Research and development

RAI: Request for additional information

RAR: Reasonably assured resources. Uranium that occurs in known mineral deposits of delineated size, grade and configuration such that the quantities which could be recovered within the given production cost ranges with currently proven mining and processing technology can be specified. Estimates of tonnage and grade are based on specific sample data and measurements of the deposits and on knowledge of deposit characteristics. NEA work on uranium:

RBMK: Russian abbreviation for graphite-moderated light water-cooled reactors. An NEA assessment of this reactor design in the context of the Chernobyl accident:

RCIC: Reactor core isolation cooling

RCPB: Reactor coolant pressure boundary

RCS: Reactor coolant system

RHR: Residual heat removal

RIA: Reactivity-initiated accident

RIP: Rod internal pressure

RNMDR: Russian National Medical Dosimetry Registry

RP: Radiological protection

RWMC: NEA Radioactive Waste Management Committee



  1. Belgian safety assessment and feasibility interim reports on the deep underground disposal of radioactive waste. The SAFIR-1 report assesed R&D programmes carried out between 1974 and 1988 on the possible disposal of radioactive waste in the Boom clay layer found in Belgium. The SAFIR-2 report assessed the work carried out in the years 1990-2000. The NEA participated in an international peer review of the SAFIR-2 report available at (pdf, 350 kb).
  2. The Finnish Research Programmes on Nuclear Power Plant Safety (Safety of nuclear power plants – Finnish national research programme)

SAP: Safety assessment principles

SAR: Safety assessment report or safety analysis report

SBLOCA: Small-break loss-of-coolant accident

SCIP: Studsvik cladding integrity project

SCK•CEN: Studiecentrum voor Kernenergie – Centre d'étude de l'énergie nucléaire (Nuclear Research Centre, Belgium)

SCRB: Safety culture of the regulatory body

SCWR: Supercritical-water-cooled reactor

SDR: Special Drawing Right

SEM: Scanning electron microscope

SER: Safety evaluation report

SETH: SESAR Thermal-hydraulics. NEA joint project.

SFR: Sodium-cooled fast reactor or short-lived radioactive waste

SG: Specialist group

SILOE: French research reactor, now dismantled

SIMS: Secondary-ion mass spectrometry

SKB: Svensk Kämbränslehantering AB (Swedish Nuclear Fuel and Waste Management Company)

SM2A: Task Group on Safety Margin Applications and Assessment (NEA)

SMR: Small modular reactor

SNF: Spent nuclear fuel. Fuel that has been irradiated in and then permanently removed from a nuclear reactor.

SNSA: Slovenian Nuclear Safety Administration

SOS: NDC Ad hoc Expert Group on Nuclear Energy and Security of Supply

SR: Speculative resources. Uranium that is thought to exist, mostly on the basis of indirect evidence and geological extrapolations, in deposits discoverable using existing exploration techniques. The location of deposits envisaged in this category could generally be specified only as being somewhere within a given region or geological trend. As the term implies, the existence and size of such resources are speculative. NEA work on uranium:

SRG: Safety review guidelines

SRP: Standard review plan

SSM: Strålsäkerhetsmyndigheten (Swedish Radiation Safety Authority)

STUK: Säteilyturvakeskus (Radiation and Nuclear Safety Authority, Finland)

SUJB: Státní úrad pro jadernou bezpecnost (State Office for Nuclear Safety, Czech Republic)


TAEK: Türkiye Atom Enerjisi Kurumu (Atomic Energy Authority, Turkey)

TAREF: Task Group on Advanced Reactor Experiment Facilities

TEDE: Total effective dose equivalent

TDB: Thermochemical Database Project. NEA joint project.

TMI: Three Mile Island

TRACE: System thermal-hydraulic code

TRANSSC: Transport Safety Standards Committee (IAEA)

TRIGA: Training, research, isotopes, General Atomics

TSO: Technical support organization

TRU: Permanent disposal of transuranic


UG: Underground

UICP: Union International des Chemins de Fers (France)

UKAEA: United Kingdom Atomic Energy Authority

UNSCEAR: United Nations Scientific Committee on the Effects of Atomic Radiation

US NRC: Nuclear Regulatory Commission of the United States


V&V: Verification and validation

VC: 1963 Vienna Convention on Civil Liability for Nuclear Damage

VHTR: Very-high-temperature reactor.

VNIINM: A.A. Bochvar High-Technology Scientific Research Institute for Inorganic Materials

VVER: Vodo-Vodyanoi Energetichesky Reaktor, a Russian-designed pressurised water reactor (also sometimes referred to as WWER)


WENRA: Western European Nuclear Regulators' Association

WASSC: Waste Safety Standards Committee (IAEA)

WG: Working group

WGFCS: NEA Working Group on Fuel Cycle Safety

WGFSM: NEA Working Group on Fuel Safety Margins

WGHOF: NEA Working Group on Human and Organisational Factors

WGIAGE: NEA Working Group on the Integrity of Components and Structures

WGIP: NEA Working Group on Inspection Practices

WGOE: NEA Working Group on Operating Experience

WGPC: NEA Working Group on Public Communication of Nuclear Regulatory Organisations

WGRISK: NEA Working Group on Risk Assessment

WGRNR: Working Group on the Regulation of New Reactors

WHO: World Health Organisation

WIPP: Waste Isolation Pilot Plant (United States)

WNU: World Nuclear University

WPDD: NEA Working Party on Decommissioning and Dismantling

WPEC: NEA Working Party on International Nuclear Data Evaluation Co-operation

WPFC: NEA Working Party on Scientific Issues of the Fuel Cycle

WPNE: NEA Working Party on Nuclear Energy Economics

WPNEM: NEA Working Party on Nuclear Emergency Matters

WPNCS: NEA Working Party on Nuclear Criticality Safety

WPRS: NEA Working Party on Scientific Issues of Reactor Systems

WWER: Vodo-Vodyanoi Energetichesky Reaktor, a Russian-designed pressurised water reactor (also sometimes referred to as VVER)

Last reviewed: 23 January February 2018