Reference

This is a Reference Page. Below is a list of Acronyms, in alphabetical order:

ABB	Asea Brown Boveri, Ltd.
AWS	American Welding Society
CREATCS	control room emergency air temperature control system
EDS	non-class 1E dc and UPS system
FRS	floor response spectra
AABVS	auxiliary/annex building ventilation subsystem
ABB	Asea Brown Boveri Company
ABWR	Advanced Boiling Water Reactor
ac/AC	alternating current
ACI	American Concrete Institute
ACL	Aktiva centrallaboratoriet (Studsvik)
ACR	Advanced CANDU Reactor
ACRS	Advisory Committee on Reactor Safeguards
ACS	Accident Confinement System
ADAMS	Agencywide Documents Access and Management System Public Electronic
ADGFOSS	ancillary diesel generator fuel oil supply system
ADS	Automatic Depressurization System
ADS-4	automatic depressurization system-Stage 4
ADVs	atmospheric dump valves
AEA	Atomic Energy Authority, UK
AEC	Atomic Energy Commission, USA
AECB	Atomic Energy Control Board
AECL	Atomic Energy of Canada, Ltd.
AEOD	NRC Office for Analysis and Evaluation of Operational Data
AESOP	Atomic Energy Simulation of Optimization (computer code)
AFA	Research program on Nuclear Waste, NKS 1994 – 1997
AFW	auxiliary feedwater
AFWS	Auxiliary Feed-Water System
AGC	Advanced Gas Centrifuge
AGR	Advanced Gas Cooled Reactor
AGRI	See RALA
AGS	Airborne Gamma Spectrometry
AHUs	air handling units
AI	automatic isolation
AICC	Adiabatic Isochoric Complete Combustion
AISC	American Institute of Steel Construction
AISI	American Iron and Steel Institute
AL	Action Level
ALARA	as low as is reasonably achievable
ALARP	As Low As Reasonably Practible
ALEX	Barents Rescue 2001 Alarm Exercise
ALI	Annual Limit on Intake (ICRP)
ALWR	advanced light water reactor
AM	Accident Management
AMAP	Arctic Monitoring and Assessment Program
AMS	Accelerator Mass Spectrometry
ANL	Argonne National Laboratory (USA)
ANP	Advanced Nuclear Power
ANS	American Nuclear Society
ANSI	American National Standards Institute
AOO	anticipated operational occurrences
AOT	Allowed Outage Time
AOV	air operated valves
APEX	Advanced Plant Experiment
APRI	Accident Phenomena of Risk Importance (Swedish severe accident research project)
APROS	Advanced Process Simulator
APWR	Advanced Pressurized Water Reactor
ARGOS	Accident Reporting and Guiding Operational System (Denmark)
ARM	area radiation monitor
ART	adjusted reference temperature
ASAR	As Operated Safety Analysis Report
ASB	Auxiliary Systems Branch
ASCE	American Society of Civil Engineers
ASDV	Atmospheric Steam Discharge Valve
ASHRAE	American Society of Heating, Refrigerating and Air Conditioning
ASI	Analysis Significant Items
ASME	American Society of Mechanical Engineers
ASME Code	American Society of Mechanical Engineers Boiler and Pressure Vessel
ASSERT	Advanced Solution of Subchannel Equations in Reactor Thermalhydraulics (computer code)
ASTM	American Society for Testing and Materials
AT	Austria (ISO abbreviation)
ATC	automatic turbine control
ATHLET	Analysis of Thermo-Hydraulics of Leaks and Transients (computer code)
ATR	Advanced Thermal Reactor
ATWS	anticipated transient without scram
AVLIS	Atomic Vapor Laser Isotope Separation
AVT	all-volatile treatment
B&W	Babcock and Wilcox
B&WOG	B&W Owner’s Group
BAC	bounding analysis curve
BAM	Bundesanstalt für Materialforschung und –prüfung, Germany
BAT	boric acid tank
BAT	Best Available Technique
BDBA	Beyond Design Basis Accident
BE	best estimate
BEIR	Committee on the Biological Effects of Ionizing Radiations
BER	Research program on Nuclear Emergency Preparedness, NKS 1994 – 1997
BH	Bottom Head
BKAB	Barsebäck Kraft AB, Sweden
BLC	Boiler Level Control
BLW	Boiling Light Water
BMU	Bundesministerium für Umweltschutz und Reaktorsicherheit, Germany
BNCT	Boron Neutron Capture Therapy
BNFL	British Nuclear Fuel, Ltd.
BNL	Brookhaven National Laboratory
BOC	beginning-of-cycle
BOK	Research program on nuclear emergency preparedness and radiological consequences, NKS 1998 – 2001
BPC	Boiler Pressure Controller
Bq	Becquerel
BRS	Danish Emergency Management Agency (Beredskabsstyrelsen); also referred to as DEMA
BTP	branch technical position
BTWC	Biolocical and Toxin Weapons Convention
BWR	boiling water reactor
BWR	Boiling Water Reactor
BWROG	Boiling Water Reactor Owners’ Group
C&I	Control and Instrumentation
CAMS	Computerized Accident Management Support System
CANDU	Canadian Deuterium Natural Uranium Heavy-Water Reactor
CAS	central alarm station
CAS	compressed and instrument air system
CASS	cast austenitic stainless steel
CAV	cumulative absolute velocity
CB	circuit breakers
CBP	computer-based procedures
CBRN	Chemical, Biological, Radiological, Nuclear
CBSS	Council of Baltic Sea States
CC	Condensate Cleaning
CCA	1. Cause Consequence Analysis 2. Common Cause Analysis
CCC	Computer and Communications Center
CCF	common cause failure
CCF	Common Cause Failure
CCFP	conditional containment failure probability
CCI	core-concrete interaction
CCI	Common Cause Initiators
CCP	Critical Channel Power
CCS	component cooling water system
CCW	component cooling water
CD	Civil Defense
CD&ER	Civil Defense and Emergency Response
CDF	core damage frequency
CDF	Core Damage Frequency
CE	Combustion Engineering
CEC	Commission of the European Communities
CEDM	Control Element Drive Mechanism
CEO	Chief Executive Officer
CERN	European Council for Nuclear Research (Conseil Europeenne pour la Recherche Nucleaire)
CET	containment event tree
CF	chemistry factor
CFD	Computational Fluid Dynamics
CFL	late containment failure
CFM	Critical Function Monitor(ing)
CFR	Code of Federal Regulations
CFS	condensate and feedwater system
CGS	Car-borne Gamma Spectrometry
CHAZOP	Computer HAZOP (Hazards and Operability)
CHF	critical heat flux
CHF	Critical Heat Flux
CHS	Committee on Human Security
CI	containment isolation
CIS	Commonwealth of Independent States
CIS	containment isolation system
CIV	containment isolation valves
CIWH	condensation induced water hammer
CLAB	Central Interim Storage Facility for Spent Nuclear Fuel, Sweden (Centrallager för använt bränsle)
CM	Corrective Maintenance
CMS	condenser air removal system
CMT	core makeup tank
CMT	Crisis Management Team
CNRA	Committee of Nuclear Regulatory Activities (OECD/NEA)
CNS	Center for Nonproliferation Studies (Monterey Institute)
COGEMA	Compagnie Generale des Matieres Nucleaires, France
COL	combined license
COLR	Core Operating Limits Report
COMMON Q COTS	common qualified platform commercial off-the-shelf
COSMOS	Russian nuclear powered satellites
CP	construction permit
CPC	Common Performance Conditions
CPG	containment performance goal
CPR	Critical Power Ratio
CPS	condensate polishing system
cps	Counts per second
CPS	Control and Protection System
CR	control room
CRD	control rod drive
CRDM	control rod drive mechanism
CRDS	control rod drive system
CREFS	control room emergency filtration system
CRL	Chalk River Laboratories
CRPPH	Committee on Radiation Protection and Public Health (OECD/NEA)
CRT	Cathode Ray Tube
CS	core support
CSA	Comprehensive Safeguards Agreement
CSA	Canadian Standards Association
CSDV	Condenser Steam Discharge Valve
CSF	critical safety function
CsI	cesium iodide
CSNI	Committee of the Safety of Nuclear Installations (OECD/NEA)
CSNI	Canadian Standards for the Nuclear Industry
CSS	Containment Spray System
CST	condensate storage tank
CTBT	Comprehensive Test Ban Treaty
CTC	Counter-Terrorism Committee (UN)
CUF	cumulative usage factor
CV	check valve
CV	Charpy V-notch
CVCS	chemical and volume control system
CVD	Cherenkov Viewing Device
CVS	chemical and volume control system
CWC	Chemical Weapons Convention
CWS	circulating water system
DA	Data Acquisition
DAC	derived air concentration
DAC	design acceptance criteria
DAD	Decide, Announce, Defend
DAS	diverse actuation system
DBA	Design Basis Accident
DBE	Design Base Earthquake
DBPB	design basis pipe break
DBT	design basis tornado
DC	Downcomer of the reactor coolant system
DC	design certification
dc/DC	direct current
DCC	Digital Control Computer
DCD	design control document
DCH	Direct Containment Heating
DD	Danish Decommissioning (Dansk Dekommissionering)
DDS	data and display processing system
DDT	Deflagration-to-Detonation Transition
DE	Germany (ISO abbreviation)
DECLG	double-ended cold leg guillotine
DEDVI	double-ended direct vessel injection
DEH	digital electrohydraulic
DEI	dose equivalent iodine
DEMA	Danish Emergency Management Agency (Beredskabsstyrelsen); also referred to as BRS
DETRA	Doses via Environmental Transport of Radionuclides (computer code)
DF	decontamination factor
DF-ET	Drift Flux-Equal Temperature
DFR	Dounreay Fast Reactor
DFRIT	Finnish Defense Forces Research Institute of Technology
DF-UT	Drift Flux-Unequal Temperature
DG	diesel generator
DHR	decay heat removal
DID	defense-in-depth
DiP	Decision in Principle
DK	Denmark (ISO abbreviation)
DKK	Danish currency (crowns, kroner)
DKV	Driftklarhetsverifiering
DMI	Danish Meteorological Institute (Danmarks Meteorologiske Institut)
DMIMS	digital metal impact monitoring system
DNB	Departure from Nucleate Boiling
DNBR	departure from nucleate boiling ratio
DNMI	Norwegian Meteorological Institute (Det norske meteorologiske institutt)
DOD	US Department of Defense
DOE	US Department of Energy
DOFs	degrees of freedom
DOP	dioctyl-phthalate polydispersed
DOS	standby diesel and auxiliary boiler fuel oil system
DOT	Department of Transportation
dps	Disintegrations per second
DR1, DR2, DR3	Danish research reactors at Risø National Laboratory
D-RAP	design reliability assurance program
DRF	Dose Reduction Factor
DSA	Deterministic Safety Analysis
DSER	draft safety evaluation report
DTS	demineralized water treatment system
DTU	Technical University of Denmark (Danmarks Tekniske Universitet)
DVI	direct vessel injection
DWS	demineralized water transfer and storage system
DWST	demineralized water storage tank
EAB	exclusion area boundary
EARP	Enhanced Actinide Removal Plant (Sellafield)
EBRD	European Bank for Reconstruction and Development
EBS	Engineered Barrier System
EC	European Commission
ECC	Emergency Control Center
ECC	Emergency Core Cooling
ECC	equilibrium cycle core
ECCS	Emergency Core Cooling System
ECI	Emergency Core Injection
ECMWF	European Center for Medium-range Weather Forecasts
ECURIE	European system for notification in case of radiological emergencies (EU)
EdF	Electricité de France
EDI	electrodeionization
EDO	NRC Executive Director for Operations
EDSS	Environmental Decision Support System
EE	Estonia (ISO abbreviation)
EF	error factor
EFDA	European Fusion Development Agreement
EFDS	equipment and floor drainage system
EFPH	Effective Full Power Hours
EFPY	effective full-power year
EFW	emergency feedwater
EFWS	Emergency Feed-Water System
EHT	effluent holdup tanks
EIA	Environmental Impact Assessment
EIB	European Investment Bank
EIRO	Forum of collaboration between seven European Intergovernmental Scientific Research Organizations
EIS	Environmental Impact Statement
EKO	Radioecological research program, NKS 1994 – 1997
ELS	plant lighting system
EM	evaluation model
EMAS	Eco Management and Audit Scheme (EU regulations)
EMC	electromagnetic compatibility
EMERCON	International system for notification in case of radiological emergencies (IAEA)
EMHI	Estonian Meteorological and Hydrological Institute
EMI	electromagnetic interference
EN 45001	EU standard for accreditation of laboratories conducting measurements onfoodstuff and issuing certificates
ENS	European Nuclear Society
ENSRA	European Nuclear Security Regulators Association
EOC	end-of-cycle
EOF	Emergency Operations Facility
EOL	End Of Life
EoO	Error of Omission
EOP	Emergency Operating Procedure
EOS	Emergency Operating Center
EP	emergency planning
EPA	US Environmental Protection Agency
EPIC	Environmental Protection from Ionizing Contaminants in the Arctic (EU)
EPR	European Pressurized Water Reactor
EPRI	Electric Power Research Institute, USA
EPRI/MRP	EPRI Materials Reliability Project
EQ	equipment qualification
EQDP	equipment qualification data package
ERA	European Research Area
ERDS	Emergency Response Data System
ERG	emergency response guidelines
ERI	Energy Research, Inc.
ERICA	Environmental Risks from Ionizing Contaminants: Assessment and Management (EU)
ERPC	Estonian Radiation Protection Center, Tallinn
ERVC	external reactor vessel cooling
ESARDA	European Safeguards Research and Development Association
ESBWR	Evolutionary Simplified Boiling Water Reactor
ESF	engineered safety feature
ESFA	engineered safety features actuation
ESFAS	engineered safety features actuation system
ESFR	European Synchrotron Radiation Facility
ESP	Early Site Permit
ESR	Electron Spin Resonance
ESW	essential service water
ET	eddy current testing
ETA	Event Tree Analysis
ETEX	European Tracer EXperiment
ETS	emergency trip system
EU	European Union
EUP	Enriched Uranium Product
EUR	European Utility Requirements
EURADOS	European Radiation Dosimetry Group
EURATOM	EU/DG17 Directorate E
EURDEP	EU Radioactivity Data Exchange Platform
EVET	Equal Velocity Equal Temperature
EVUT	Equal Velocity-Unequal Temperature
EWS	Emergency Water Supply
FAO	United Nations Food and Agriculture Organization
FARO	Test facility at Joint Research Center Ispra for studying fuel-coolant interaction
FAS	Fast Acting Scram
FASSET	Framework for Assessment of Environmental Impact (EU)
FBACS	fuel building air cleanup system
FBR	Fast Breeder Reactor
FBR	Feed, Bleed and Relief
FBTA	function-based task analysis
FCC	first cycle core
FCI	fuel-coolant interactions
FCU	fan coil unit
FDA	final design approval
FE	finite element
FEMA	Federal Emergency Management Agency
FEP	Features, Events and Processes
FHA	fuel-handling accident
FHAVS	fuel handling area ventilation subsystem
FI	Finland (ISO abbreviation)
FIM	Earlier: Finnish currency (marks, markkaa)
FIV	flow-induced vibration
FLB	feedwater line break
FME	foreign material exclusion
FMEA	Failure Mode and Effects Analysis
FMI	Finnish Meteorological Institute
FN	ferrite number
FO	Faroe Islands (ISO abbreviation)
FOI	Swedish Defense Research Agency (Totalförsvarets forskningsanstalt)
FoU	Forskning och utveckling
FP	1. EU’s Framework Program 2. Fission Product(s)
FP	Full Power
FPDS	flat panel display system
FPS	fire protection system
FRC	US Federal Radiation Council
FRED	FASSET Radiation Effects Database (EU; see FASSET)
FRIT	Danish Science Research Councils’ Instrument Service (Host organization of the NKS Secretariat; Forskningsrådenes Instrument Tjeneste ApS)
FSAR	Final Safety Analysis Report
FSER	final safety evaluation report
FTA	Felträdsanalys
FTP	File Transfer Protocol
FUD	Forskning, utveckling, demonstration
FV&V	final verification and validation
FVW	Fussell-Vesely worth
FW	feedwater
FZK	Forschungszentrum Karlsruhe
G24	All western European countries plus USA, Canada, Japan, Australia, New Zealand, and Turkey
G7	USA, Japan, Germany, France, UK, Italy and Canada
GALE	gaseous and liquid effluent
GAN	Nuclear safety authority of the Russian Federation (Gozatomnadzor)
GAN/HQ	GAN’s headquarters, Moscow, Russia
GAN/NED	GAN’s regional office, St. Petersburg, Russia (North Eastern District)
GARDS	Global Atmospheric Radionuclide Detection System
GCEP	Gas Centrifuge Enrichment Plant
GCHWR	Gas Cooled Heavy Water Reactor
GCR	Gas Cooled Reactor
GDC	general design criteria/criterion
GE	General Electric
Geislavarnir	Icelandic Radiation Protection Institute (Geislavarnir ríkisins)
GFR	Gas-Cooled Fast Reactor
GGR	Gas cooled Graphite Reactor
GIS	Graphical Information System
GL	generic letter
GLWR	Graphite Light Water Reactor
GPS	1. Global Positioning System 2. Goal Planning System
Gr	Geislavarnir ríkisins (Icelandic Radiation Protection Institute)
GRCAs	gray rod cluster assemblies
GRS	Gesellschaft für Anlagen- und Reaktorsicherheit mbH
GSI	generic safety issue
GSS	turbine gland seal system
GTMHR	Gas Turbine Modular Helium Reactor
GTRI	Global Threat Reduction Initiative
Gy	Gray
H2TS	hierarchical, two-tiered scaling
HAEA	Hungarian Atomic Energy Agency
HAMISA	Hole Ablation Modelling In Severe Accidents (computer code)
HAZ	Heat Affected Zone
HAZ	heat-affected zone
HAZOP	Hazards and Operability
HCCF	Human Common Cause Failure
HCD	Head of Civil Defense
HCF	high cycle fatigue
HCLPF	high confidence that the particular SSC will have a low probability of failure
HCMS	hydrogen concentration monitoring system
HCSD	hot/cold shutdown
HEDs	human engineering discrepancies
HEL	high-energy line
HELB	high-energy line break
HELCOM/MORS	Helsinki Commission/Monitoring Of Radioactive Substances in the Baltic Sea
HEM	Homogeneous Equilibrium Model
HEP	human error probability
HEPA	high-efficiency particulate air
HEU	Highly Enriched Uranium
HFE	Human Factor Engineering
HFP	hot full-power
HFS	Human Factors Society
HIC	high-integrity containers
HICB	Instrumentation and Controls Branch
HIM	See KTM
HIRLAM	HIgh Resolution Limited Area Model (Nordic numerical weather predictionmodel)
HLHS	heavy load handling system
HLW	High Level Waste
HPCI	high-pressure coolant injection
HPGe	High Purity Germanium (Detector)
HPI	high-pressure injection
HPME	High Pressure Melt Ejection
HPS	Health Physics Society
HPSI	high-pressure safety-injection
HR	High Resolution
HRA	Human Reliability Analysis
HRICPMS	High Resolution Inductively Coupled Plasma Mass Spectrometry
HRP	Halden Reactor Project
HSI	Human – System Interface(s)
HSI	human-system interface
HTG	Högsta tillåtna gränsvärde
HTGR	High Temperature Gas Cooled Reactor (graphite moderated)
HTML	Hyper Text Markup Language
HTR	High Temperature Reactor
HTS	Heat Transport System
HTTP	Hyper Text Transfer Protocol
HVAC	High Voltage Alternating Current
HVAC	heating, ventilation, and air conditioning
HVDC	High Voltage Direct Current
HWBLWR	Heavy Water Boiling Light Water Reactor
HWGCR	Heavy Water Gas Cooled Reactor
HWLWR	Heavy Water Light Water Reactor
HWP	Heavy Water Plant
HWR	Heavy Water Reacto r
HX	heat exchanger
HYDNA	Hydraulic Network Analysis (extinct computer code)
HZP	hot zero-power
I&C	Instrumentation and Control
I/O	input/output
IACRS	Inter-Agency Committee on Radiation Safety (IAEA)
IAEA	International Atomic Energy Agency
IAS	instrument air system
IASAP	International Arctic Seas Assessment Project (IAEA)
IASCC	Irradiation-Assisted Stress Corrosion Cracking
IBIF	Intermittent Buoyancy Induced Flow
IC	intact containment
ICC	inadequate core cooling
ICCDP	incremental conditional core damage probability
ICEM	International Conference(s) on Environmental Remediation and Radioactive Waste Management
ICI	In-Core Instrumentation
ICJ	International Court of Justice
ICPMS	Inductively Coupled Plasma Mass Spectrometry
ICRE	International Commission on Radiation Education
ICRP	International Commission on Radiological Protection
ICRR	International Congress of Radiation Research
ICRU	International Commission on Radiation Units and Measurements
ICSB	Instrumentation and Control Systems Branch
IDC	International Data Center
IDS	Class 1E dc system
IE	Initiating Event
IEA	International Energy Agency
IEB	Inspection and Enforcement bulletin
IEC	International Electrotechnical Commission
IEEE	Institute of Electrical and Electronics Engineers
IFE	Institute for Energy Technology (Institutt for Energiteknikk), Norway
IFM	intermediate flow mixing
IGSC	Integrated Group for the Safety Case (OECD/NEA)
IGSCC	Inter-Granular Stress Corrosion Cracking
IHP	integrated head package
IIASA	International Institute for Applied Systems Analysis
IIS	in-core instrumentation system
IL	Intervention Level
ILO	International Labor Organization
ILRT	integrated leak rate testing
ILW	Intermediate Level Waste
IN	information notice
INEEL	Idaho National Engineering and Environmental Laboratory
INEL	Idaho National Engineering Laboratory
INES	International Nuclear Event Scale (IAEA)
INEX	International Emergency Preparedness Exercise (OECD/NEA)
INIS	International Nuclear Information System (libraries etc.)
INPO	Institute of Nuclear Power Operations
INPP	Ignalina Nuclear Power Plant, Lithuania
INSAG	International Nuclear Safety Advisory Group (IAEA)
INSITE	Independent Site Investigation Tracking & Evaluation (SKI)
IPCC	Intergovernmental Panel on Climate Change
IPPC	Integrated Pollution Prevention and Control Directive (EU)
IPSAC	investment protection short-term availability controls
IRPA	International Radiation Protection Association
IRPI	Icelandic Radiation Protection Institute (Geislavarnir ríkisins)
IRWST	in-containment refueling water storage tank
IS	Iceland (ISO abbreviation)
ISA	Instrument Society of America
ISA	1. Integrated Sequence Analysis 2. Integrated Safety Analysis
ISDN	Integrated Service Digital Network
ISER	Intrinsically Safe and Economical Reactor
ISI	In-Service Inspection
ISK	Icelandic currency (crowns, krónur)
ISLOCA	intersystem loss-of-coolant accident
ISLOCA	interfacing systems loss-of-coolant
ISO	International Standardization Organization
ISO 14000	ISO standards on environmental management systems
ISO 9000	ISO standards on quality systems
ISOCS	In-Situ Object Counting System
ISOE	Information System on Occupational Exposure (joint OECD/NEA and IAEA activity)
ISP	Internet Service Provider
ISR	International Society of Radiology
IST	In-Service Testing
ISTC	International Science and Technology Center, Moscow, Russia
IT	Information Technology
ITAAC	inspection, test, analyses, and acceptance criteria
ITER	International Thermonuclear Experimental Reactor
ITG	Issue Task Group
ITP	initial test program
ITRAP	Illicit Trafficking Radiation Detection Assessment Program
IUR	International Union of Radioecologists
IVO	Imatran Voima Oy, Finland (IVO Group includes IVO Power Engineering and Loviisa NPP) – now belonging to Fortum
JINEX	Joint Internationa Nuclear Emergency Exercises (OECD/NEA)
JRC	EU’s Joint Research Center, Ispra, Italy
K	(Degrees) Kelvin
KAN	Nuclear safety and waste management research program, NKS 1990-1993
KASAM	National Council for Nuclear Waste, Sweden (Statens råd för kärnavfallsfrågor)
KBS-3	Kärnbränslecykelns slutsteg – Använt kärnbränsle
Kd	Distribution coefficient
KIPT	Kharkov Institute for Science and Technology, Ukraine
KLDRA	Combined interim storage and final repository for low and medium level radioactive waste, Himdalen, Norway (Kombinert lager og deponi for lavt og middels radioaktivt avfall)
KNPP	Kola Nuclear Power Plant, Russia
KROTOS	Test facility at Joint Research Center Ispra for studying steam explosions
KSU	Nuclear Training and Safety Center, Sweden (Kärnkraftsäkerhet och utbildning AB)
KTH	Royal Institute of Technology, Sweden (Kungliga Tekniska Högskolan); also referred to as RIT
KTM	Ministry of Trade and Industry, Finland (Kauppa- ja teollisuusministeriö, Handels- och industriministeriet); also referred to as HIM
KU	Investigation of Consequences, Sweden (Konsekvensutredning)
LBB	Leak Before Break
LBHSs	large-bore hydraulic snubbers
LBLOCA	large-break loss-of-accident accident
LCF	low cycle fatigue
LCO	Limiting Conditions for Operation
LCSs	local control stations
LDS	leakage detection system
LEFM	linear elastic fracture mechanics
LER	Licensee Event Report
LERF	large early release fraction
LEU	Low Enriched Uranium
LFR	Lead-Cooled Fast Reactor
LIBS	Laser Induced Breakdown Spectrometry
LIVEX	Barents Rescue 2001 Live Exercise
LLHS	light load handling system
LLOCA	large LOCA
LLW	Low Level Waste
LMFW	loss of main feedwater
LNPP	Leningrad Nuclear Power Plant, Russia ("Sosnovyy Bor")
LNT	Linear No Threshold dose – response model
LOC	Loss of Coolant
LOC/LOECC	Loss of Coolant with Coincident Loss of Emergency Core Cooling
LOCA	Loss of Coolant Accident
LOF	Loss Of Flow (accident)
LOFT	loss-of-flow tests
LOFTRAN	transient and SGTR computer analysis code
LONF	loss of normal feedwater
LOOP	loss of offsite power
LOP	Loss of Pumping
LOR	Loss of Regulation
LORACON	Local Radioactivity Control
LORAKON	See LORACON
LP	low pressure
LPSA	Living PSA
LPSI	low pressure safety injection
LPZ	low population zone
LRA	license renewal application
LRF	large release frequency
LSA	Low Specific Activity
LST	large-scale tests
LSTF	Large-Scale Test Facility
LT	Lithuania (ISO abbreviation)
LTA	Logic Tree Analysis
LTC	long-term cooling
LTOP	low-temperature overpressure protection
LV	Latvia (ISO abbreviation)
LWBR	Light Water Breeder Reactor
LWCHWR	Light Water Coolant Heavy Water Reactor
LWGR	Light Water Cooled Graphite Moderated Reactor
LWR	Light Water Reactor
LWR	light water reactor
MAAP4	Modular Accident Analysis Program
MAGNOX	Natural uranium-metal fuel in magnesium-aluminum-beryllium alloy cladding
manSv	man-sievert
Marina	Project supported by the European Commission to evaluate the radiological impact of natural and anthropogenic radioactivity in the sea and to provide an overall view of the radiological exposure of the populations to sources of radioactivity in the sea
Marina Balt	A Marina project regarding the Baltic sea, arranged in 1996 - 1998 (cf. Marina)
MÁU	Environmental Impact Statement, Iceland (Mat á umhverfisáhrif)
MBA	Material Balance Area
MC&A	Material Control and Accountability
MCC	Main Circulation Circuit
MCCI	Molten Core – Concrete Interaction
MCCR	Ministry of Corporate and Consumer Relations
MCP	Main Circulation Pump
MCR	main control room
MCRE	main control room envelope
MCS	Maintenance Cooling System
MELCOR	Integral severe accident analysis computer code
MEP	Member of the European Parliament
MEPRD	Ministry of Environmental Protection and Regional Development, Latvia;also referred to as VARAM
MFCS	main feedwater control system
MFCV	main feedwater control valve
MFIV	main feedwater isolation valve
MFRV MFW	main feedwater regulation valve main feedwater
MFWS	main feedwater system
M-G	motor-generator
MHD	Magneto hydrodynamics
MI	Maintenance Indicator
MIL	Military
milli-k	Unit of reactivity for reactor physics
MINATOM	Ministry for Atomic Energy Issues, Russia
MIT	Massachusetts Institute of Technology
MKB	In Finland: Environmental Impact Assessment (miljökonsekvensbedömning) In Sweden: miljökonsekvensbeskrivning, which means either Environmental Impact Statement (document) or Environmental Impact Assessment (process)
ML	Mid-Loop
MLOCA	Medium LOCA
MLW	Medium Level Waste
MMI	1. Man-Machine Interaction 2. Man-Machine Interface
M-MIS	man-machine interface system
MMSVs	Main Steam Safety Valves
MORS	Monitoring of Radioactive Substances in the Baltic Sea, an intergovernmental group of experts under HELCOM 1986 – 1996; cf. HELCOM, HELCOM/MORS and MORS-PRO
MORS-PRO	The MORS project, since 1996 carried out under the HELCOM umbrella
MOV MRP MS	motor operated valve Materials Reliability Program main steam
MOX	Mixed Oxide Reactor Fuel
MPC&A	Nuclear Materials Protection, Control And Accounting
MPP	Marked Point Process
MS	Mass Spectrometry
MS&FW	main steam and feedwater
MSCo	Murmansk Shipping Company, Russia
MSGTR	multiple steam generator tube rupture
MSI	Maintenance Significant Items
MSIV	main steam isolation valve
MSLB	main steamline break
MSR	Molten Salt Reactor
MSSS	main steam supply system
MSV	Main Safety Valve
MTC	Moderator Temperature Coefficient
MTO	Man-Technology-Organization (Människa-Teknik-Organisation)
MUSTER	Multi User System for Training of Emergency Response
MUX	Multiplexer
MWe	Megawatt electric energy
MWt	Megawatt thermal energy
NACE	National Association of Corrosion Engineers
NASA	US National Aerodynamics and Space Administration
NATO	North Atlantic Treaty Organization
NCC	Natural Convection Cooldown
NCIG	Nuclear Construction Issues Group
NDA	Non-Destructive Analysis
NDEP	nondestructive examination
NDEP	Northern Dimension Environmental Partnership
NDT	Non-Destructive Testing
NDT	nil-ductility temperature
NE	Nuclear Electric, UK
NEA	Nuclear Energy Agency (under OECD)
NEMA	National Electrical Manufacturers Association
NEP	Nordic Nuclear Emergency Preparedness Group
NEPTUNO	Nuclear European Platform for Training and University Organizations
NFPA	National Fire Protection Association
NGO	Non-Governmental Organization(s)
NGU	Geological Survey of Norway (Norges geologiske undersøkelse)
NI	nuclear island
NIB	Norwegian Investment Bank
Ni-Cr-Fe	nickel-chromium-iron
NII	Nuclear Installations Inspectorate, UK
NILU	Norwegian Institute for Air Research (Norsk institutt for luftforskning)
NIRH	National Institute of Radiation Hygiene (SIS), Denmark
NIS	Newly Independent States
NKA	Nordiska Kontaktorganet för Atomenergifrågor (Predecessor of NKS)
NKS	Nordic Nuclear Safety Research (Nordisk KerneSikkerhedsforskning)
NLH	Norwegian Agricultural University (Norges Lantbrukshøjskole)
NMR	Nordic Council of Ministers (Nordiska ministerrådet)
NNWS	Non-Nuclear-Weapon States
NO	Norway (ISO abbreviation)
NOK	Norwegian currency (crowns, kroner)
NOPE	NEA's Office for Press Entertainment
NORM	Naturally Occurring Radioactive Materials
NOU	Norwegian Public Investigations (Norges offentlige utredninger)
NPD	Nuclear Power Demonstration
NPP	Nuclear Power Plant
NPPA	National Physical Planning Agency, Iceland
NPSAG	Nordic PSA Group
NPSH	Net Positive Suction Head
NPT	Non-Proliferation Treaty
NRA	Nuclear Energy Authority
NRC	US National Regulatory Commission
NRPA	Norwegian Radiation Protection Authority (Statens strålevern)
NRPB	National Radiation Protection Board, UK
NRPS	Nordic Radiation Protection Society; also referred to as NSFS
NSA	Nuclear Safety Account (under EBRD)
NSC	Nuclear Science Committee (under OECD/NEA)
NSFS	Nordic Society for Radiation Protection (Nordiska sällskapet för strålskydd)
NSG	1. Nuclear Suppliers Group 2. Nuclear Suppliers Guidelines
NTNU	Norwegian University of Science and Technology
NUCIRC	Nuclear Circuits (computer code)
NUEXCO	Nuclear Exchange Corporation
NUSS	Nuclear Safety Standards (IAEA)
NWFZ	Nuclear Weapon-Free Zones
NWS	Nuclear-Weapon States
O&M	Operation and Maintenance
OBE	operating-basis earthquake
OCS	operation and control centers system
ODCM	offsite dose calculation manual
OECD	Organization for Economic Cooperation and Development
OER	operating experience review
OH	Ontario Hydro
OIL	Operational Intervention Level
OKG	Oskarshamn NPP, Sweden (Oskarshamn KraftGrupp AB)
OL	operating license
OM	operation and maintenance
OMT	Object Modelling Technique
OPDMS	on-line power distribution monitoring system
OPEC	Organization of Petroleum Exporting Countries
OPS	onsite power systems
OSA	operational sequence analysis
OSC	operational support center
OSPAR	Convention for the Protection of the Marine Environment of the North-East Atlantic
OSU	Oregon State University
P&ID	piping and instrumentation drawings
P/T	pressure and temperature
PA	Performance Assessment
PACOMA	Performance Assessment of the Geological Disposal Medium-Level and Alpha Waste in a Clay Formation in Belgium
PAHO	Pan American Health Organization
PAM	postaccident monitoring
PAP	Decision in Principle Process
PAR	passive autocatalytic recombiner
PASCAL	PFM Analysis of Structural Components in Ageing LWRs
PASS	postaccident sampling system
PASULA	Computer code modelling structural and thermal behavior of instrument tube penetrations in the reactor vessel lower head
PBMR	Pebble Bed Modular Reactor
PCA	primary coolant activity
PCCS	Passive Containment Cooling System
PCCWST	passive containment cooling water storage tank
PCP	process control program
PCRV	Pre-Stressed Concrete Reactor Vessel
PCS	passive containment cooling system (AP1000)
PCS	Purification and Cooling System
PCT	Peak Cladding Temperature
PDMS	Plant Design Management System
PFM	Probabilistic Fracture Mechanics
PfP	Partnership for Peace
PFR	Prototype Fast Reactor
PGA	peak ground acceleration
PGS	plant gas systems
PGSA	Pickering Generating Station A
PHARE	Poland Hungary Aid for Reconstruction of the Economy, EU (later includingall central and eastern European countries)
PHRS	Passive Heat Removal System
PHS	US Public Health Service
PHTS	Primary Heat Transport System
PHW	Pressurized Heavy Water
PHWR	Pressurized Heavy Water Reactor
PID	Process Influence Diagram
PIFRAP	Computer code for calculating crack growth in pipes
PIPA	Photon Induced Positron Annihilation
PIRT	phenomena identification and ranking table
PIUS	Process Inherent Ultimate Safety (plant design by ABB Atom, Sweden)
PIV	Physical Inventory Verification
PL	Poland (ISO abbreviation)
PLC	programable logic controller
PLEX	Plant License Extension
PLHR	peak linear heat rate
PLIM	Plant Life Management
PLS	plant control system
PM	Preventive Maintenance
PMF	probable maximum flood
PMP	probable maximum precipitation
PMS	protection and safety monitoring system
PMS	DEMA’s Permanent Measurements System
POP	Post Office Protocol
PORV	power-operated relief valve
POV	power-operated valve
ppm	Parts per million
PPP	1. Polluter Pays Principle 2. Point to Point Protocol
PPS	Plant Protection System
PPT	Public Participation and Transparency
PRA	Probabilistic Risk Assessment
PREACS	pump room exhaust air cleanup system
PRESCON2	Pressure Containment (computer code)
PRHR	Passive Residual Heat Removal
PRHR HX	passive residual heat removal heat exchanger
PRIS	Nuclear Power Reactor Information System (IAEA Database)
PS	1. Process System 2. Predictive Simulator
PSA	Probabilistic Safety Analysis
PSAI	plant specific action items
PSAR	Preliminary Safety Analysis Report
PSARV	pressurizer safety and relief valve
PSB	Power Systems Branch
PSD	power spectral density
PSDF	power spectral density function
PSI	preservice inspection
PSI	Proliferation Security Initiative
PSS	primary sampling system
PSV	pressurizer safety valve
PTLR	pressure-temperature limits report
PTS	pressurized thermal shock
PVRC	Pressure Vessel Research Council
PWHT	post weld heat treatment
PWR	Pressurized Water Reactor
PWS	potable water system
PWSCC	primary water stress corrosion cracking
PXS	passive core cooling system
PZR	pressurizer
QA	Quality Assurance
QC	Quality Control
QDPS	qualified data processing system
QF	Quality Factor
QG	NRC Quality Group
QMS	quality management system
QRA	Quantified Risk Assessment
QUENCH	Test facility at Forschungszentrum Karlsruhe, Germany
R&D	Research and Development
R&M	Reliability and Maintainability
R2	Test reactor at Studsvik, Sweden
RAD	Radioecology research program, NKS 1990 – 1993
RADWASS	Radioactive Waste Management Standards (IAEA)
RAI	request for additional information
RAK	Reactor safety research program, NKS 1994 – 1997
RALA	Icelandic Agricultural Research Institute; also referred to as AGRI
RAM	Radioactive Material
RAMA	Reactor Analysis Implicit Algorithm
RAMI	reliability, availability, maintainability, and inspection
RAP	reliability assurance program
RAT	reserve auxiliary transformer
RAW	risk achievement worth
RB	Reactor Building
RBMK	Russian "Channelized Large Power Reactor" (water-cooled graphite-moderated reactor)
RC	reactor coolant
RCA	radiologically controlled area
RCCA	rod cluster control assembly
RCDT	reactor coolant drain tank
RCL	reactor coolant loop
RCM	Reliability Centered Maintenance
RCP	reactor coolant pump
RCPB	reactor coolant pressure boundary
RCS	Reactor Coolant System
RDBMS	Relational DataBase Management System
RDC	Radiation Protection Center, Riga
RDD	Radiological Dispersion Devices (“dirty bombs”)
RDIPE	Research and Development Institute of Power Engineering, Russia (alsoknown as the Adamov Institute, with branches in Moscow and St. Petersburg
RECRIT	Computer code for BWR recriticality and reflooding analyses
REID	Risk of Exposure Induced Death
rem	roentgen equivalent man (unit of radiation exposure)
REPU	Reprocessed Uranium
RES	NRC Office of Nuclear Regulatory Research
RES	Rock Engineering System
RESUME	Rapid Environmental Surveying Using Mobile Equipment (NKS)
RETS	radiological effluent technical specifications
RETU	Finnish Research Program on Reactor Safety (Reaktoriturvallisuuden tutkimusohjelman)
RF	1. Resuspension Factor 2. Russian Federation
RFA	robust fuel assemblies
RFC	Request For Comments
RFI	radio frequency interference
RG	regulatory guide
RH	relative humidity
RHR	Residual Heat Removal
RIA	Reactivity Initiated Accident
RIE	Reactivity Initiated Event
RIF	Risk Increase Factor
RIH	Reactor Inlet Header
RI-ISI	Risk-Informed In-Service Inspection
RIMPUFF	Risø’s Short Distance Model for Dispersion of Radioactive Material
RISCOM	Risk Communication – Model for transparency; and EU project
RIT	Royal Institute of Technology, Sweden (Kungliga Tekniska Högskolan); also referred to as KTH
RMA	Ranstad Mineral AB
RMI	reflective metallic insulation
RMS	radiation monitoring system
RMS	Radionuclide Monitoring System
RMWR	Reduced Moderation Water Reactor
RNS	normal residual heat removal system
RO	reactor operator
RO	reverse osmosis
ROAAM	Risk Oriented Accident Analysis Methodology
RODOS	Real-Time On-Line Decision Support System for Nuclear Emergency Management (EU)
ROH	Reactor Outlet Header
ROSA	Rig of Safety Assessment
RPC	Radiation Protection Center, Vilnius
RPS	reactor protection system
RPV	Reactor Pressure Vessel
RRSP	Regional Radiological Security Partnership
RRW	risk reduction worth
RSB	Reactor Systems Branch
RSC	Radioactive Substances Committee
RSG	Replacement Steam Generator
RSP	Radiological Security Partnership
RSR	remote shutdown room
RSS	remote shutdown station
RSW	remote shutdown workstation
RT	reactor trip
RTD	resistance temperature detector
RTD	Resistance Temperature Detectors
RTDP	revised thermal design procedure
RTG	Radioactive Thermal Generator
RTNSS	regulatory treatment of non-safety systems
RTP	rated thermal power
RTS	reactor trip system
RU	Russian Federation (ISO abbreviation)
RV	reactor vessel
RVH	reactor vessel head
RVHV	reactor vessel head vent
RVLIS	reactor vessel level indication system
RWM	Radioactive Waste Management
RWMC	Radioactive Waste Management Committee (OECD/NEA)
RWS	raw water system
RWST	refueling water storage tanks
S/G	steam generator
SACF	single active component failure
SADT	Structured Analysis and Design Technique
SAFDL	specified acceptable fuel design limit
SALP	Systematic Assessment of Licensee Performance
SAM	seismic anchor motions
SAM	1. Severe Accident Management 2. Project coordination and administrative services, NKS 1990 – 1997 (samordningsfunktionen)
SAMDA	severe accident mitigation design alternative
SAMG	Severe Accident Management Guidelines
SAR	1. Search And Rescue 2. Safety Analysis Report
SARA	Severe Accident Recriticality Analysis (EU project 1997-1998)
SAT	systematic approach to training
SAVE	Spatial Analysis of Vulnerable Ecosystems in Europé (EU project)
SBA	Cross-disciplinary activities, NKS 1998 – 2001
SBLOCA	small-break loss-of-coolant accident
SBO	station blackout
SBWR	Simplified Boiling Water Reactor
SC	seismic category
SCC	stress-corrosion cracking
SCDAP/RELAP5	Computer code modelling in-vessel severe accident phenomena
SCMP	software configuration management plan
SCS	Shut-Down Cooling System
SCWR	Super-Critical Water-Cooled Reactor
SDM	Safety Design Matrices
SDS	Safety Depressurization System
SE	Sweden (ISO abbreviation)
SEA	Science and Engineering Associates, Inc.
SEA	Strategic Environmental Assessment
SECY	Office of the Secretary of the Commission
SEK	1. Swedish currency (crowns, kronor) 2. Svenska Elektriska Kommissionen 3. Project coordination and administrative services, NKS 1998 – 2005 (sekretariatsfunktionen)
SER	safety evaluation report
SESAM	Senior Experts on Severe Accident Management (OECD/NEA)
SESAR	Senior Experts on Safety and Research (OECD/NEA)
SFCV	startup feedwater control valve
SFD	severe fuel damage
SFIV	startup feedwater isolation valve
SFL	Final Repository for Long-Lived Waste, Sweden (Slutförvar För Långlivat avfall)
SFP	spent fuel pool
SFPCPS	spent fuel pool cooling and purification system
SFR	1. Final Repository for Radioactive Operational Waste, Sweden (Slutförvar För Reaktoravfall) 2. Sodium-Cooled Fast Reactor
SFS	startup feedwater system
SFS	spent fuel pool cooling system
SFW	startup feedwater
SG	steam generator
SG	Strategy Generator
SGBS	steam generator blowdown system
SGD	subgroup design
SGR	Sodium Graphite Reactor
SGS	steam generator system
SGSV	steam generator safety valve
SGTR	Steam Generator Tube Rupture
SGU	Geological Survey of Sweden (Sveriges Geologiska Undersökning)
SI	State Identification
SIK	Reactor safety research program, NKS 1990 – 1993
SIMULATE-3K	Computer code modelling core neutronics and thermal-hydraulics
SIP	Swedish International Project/Nuclear Safety (under SKI)
SIR	Safeguards Inspection Report (IAEA)
SIS	1. Danish Radiation Protection Authority (Statens Institut for Strålehygiejne) 2. Safety Injection System 3. Standardiseringskommissionen i Sverige
SIUS	International Development Cooperation Program of the Swedish Radiation Protection Authority (SSIs internationella utvecklingssamarbete)
SJV	Statens jordbruksverk, Sweden
SKB	Swedish Nuclear Fuel and Waste Management Co. (Svensk kärnbränslehantering AB)
SKC	Svenskt kärntekniskt centrum (Swedish Center for Nuclear Technology)
SKI	1. Swedish Nuclear Power Inspectorate (Statens kärnkraftinspektion) 2. Swedish Quality Index (Svenskt Kvalitetsindex)
SKIFS	SKI Regulations (SKIs författningssamling)
SLB	steam line break
SLU	Swedish University of Agricultural Sciences (Sveriges lantbruksuniversitet)
SLV	Statens livsmedelsverk, Sverige
SM	System Manager
SMA	seismic margin analysis
SMACNA	Sheet Metal and Air Conditioning Contractors’ National Association
SMART	System-Integrated Modular Advanced Reactor
SMHI	Swedish Meteorological and Hydrological Institute (Sveriges meteorologiska och hydrologiska institut)
SMS	special monitoring system
SMS	Short Message Services
SNAP	Severe Nuclear Accident Program
SNNAP	Swedish Nuclear Non-Proliferation Assistance Program (SKI)
SOAR	State Of the Art Report
SOERs	Significant Operating Event Reports
SOMP	software operation and maintenance plan
SOPHT	Simulation of Primary Heat Transport (computer code)
SOS	Reactor safety, waste management and radiation protection research program, NKS 1998 – 2001
SPDS	safety parameter display system
SPE	Solar Particle Events
SPES	Simulatore per Esperienze di Sicurezza
SPLB	NRC Plant Systems Branch
SPM	software program manual
SPSA	Shutdown PSA
SPWR	Simplified Pressurized Water Reactor
SQAP	software quality assurance plan
SR	safety-related
SR	surveillance requirement
SRM	staff requirements memorandum
SRO	senior reactor operator
SROA	safety-related operator action
SRP	Standard Review Plan
SRSS	square root of the sum of squares
SRST	spent resin storage tank
SRV	safety relief valve
SRV	Swedish Rescue Services Agency (Statens räddningsverk)
SRV	Safety Relief Valve
SRXB	Reactor Systems Branch
SS	shift supervisor
SSAC	State System for Accountancy for and Control of Nuclear Materials
SSAR	standard safety analysis report (AP600)
SSCs	structures, systems and components
SSDs	System Specification Documents (AP600)
SSE	safe-shutdown earthquake
SSI	soil-structure interaction
SSI	Swedish Radiation Protection Authority (Statens strålskyddsinstitut)
SSIFS	SSI Regulations (SSIs författningssamling)
SSP	software safety plan
SSS	secondary sampling system
SST	small scale test
STA	shift-technical advisor
STARC	Stop – Think – Act – Review – Communicate
START	US – Soviet nuclear disarmament treaty
STD	standard
STF	Säkerhetstekniska föreskrifter
STS	standard technical specification
STUK	Finnish Radiation and Nuclear Safety Authority (Säteilyturvakeskus, Strålsäkerhetscentralen)
SUFS	startup feedwater system
SUFWS	startup feedwater system
Sv	Sievert
SV	Signal Validation
SVAFO	AB SVAFO (Sydkraft, Vattenfall, Forsmark, Oskarshamn), presently owned by Studsvik AB
SVVP	software verification and validation plan
SWMS	solid waste management system
SWS	service water system
T/H	Thermal-Hydraulics
TACIS	Technical Assistance to the Commonwealth of Independent States, EU
TASCS	thermal stratification, cycling and striping
Tavg	average temperature
TCDC	Technical Cooperation among Developing Countries
TCF	Technical Cooperation Fund (IAEA)
TCP	1. Technical Cooperation Program (IAEA) 2. Transmission Control Protocol
TCS	turbine building closed cooling system
TDS	turbine island vents, drains, and relief system
TECDOC	Technical Document (IAEA)
TEDE	total effective dose equivalent
TGSCC	transgranular stress corrosion cracking
T-H	thermal-hydraulic
THD	total harmonic distortion
the Code	ASME Boiler and Pressure Vessel Code
THERP	technique for human error rate prediction
THORP	Thermal Oxide Reprocessing Plant at Sellafield, UK
TID	total integrated dose
TLD	ThermoLuminescent Dosimeter/Dosimetry
TMI	Three Mile Island
TOFFEA	Two Fluid Flow Equation Analysis (computer code)
TopSafe	Regular international topical meetings on reactor safety and new concepts in nuclear power production (arranged by ENS in cooperation with the hostcountry’s counterpart)
TopSeal	Regular international topical meetings demonstrating the practical achievements of nuclear waste management and disposal (arranged by ENS in cooperation with the host country’s counterpart)
TQM	Total Quality Management
TRADOS	Meteorological long-range trajectory and dispersion model
TRAM	Transport of Radioactive Material
TRIGA	Training and Research Reactor
TS	technical specifications
TS	Tracking Simulator
TSC	Technical Support Center
TSP	trisodium phosphate
TUD	Availability, maintenance and operation (Tillförlitlighet, underhåll och drift)
TVO	Industrial Power Ltd., Finland (Teollisuuden Voima Oy, Industrins Kraft)
UAT	unit auxiliary transformers
UBC	Uniform Building Code
UCSB	University of California, Santa Barbara
UET	unfavorable exposure time
UGS	Urban Gamma Spectrometry
UHS	ultimate heat sink
UN	United Nations
UNEP	United Nations Environmental Program
UNIDIR	United Nations Institute for Disarmament Research
UNIDO	United Nations Industrial Development Organization
UNIPEDE	International Union of Producers and Distributors of Electrical Energy, Paris, France
UNSCEAR	United Nations Scientific Committee on the Effects of Atomic Radiation
UOC	Uranium Ore Concentration
UPS	uninterruptable power supply
UR	Utility Requirements
URD	Utility Requirements Document
URL	1. Underground Research Laboratory 2. Uniform Resource Locator
URS	ultimate rupture strength
US	United States of America (ISO abbreviation)
US NRC	US Nuclear Regulatory Commission
USACDA	US Arms Control and Disarmament Agency
USD	US currency (dollars)
USE	upper-shelf energy
USEC	US Enrichment Corporation
USI	unresolved safety issues
UT	ultrasonic testing
UTC	Universal Time Coordinate
UVUT	Unequal Velocity Unequal Temperature
V&V	verification and validation
VALDOR	Values in Decisions on Risk
VAPORE	valve and pressure operating related experiments
VARAM	See MEPRD
VAS	radiologically controlled area ventilation system
VATESI	Nuclear Safety Authority, Vilnius, Lithuania
VB	Vacuum Building
VBS	nuclear island nonradioactive ventilation system
VC	Vacuum Chamber
VCS	containment recirculation cooling system
VDU	video display unit
VES	main control room emergency habitability system
VFS	containment air filtration system
VHP	vessel head penetration
VHS	health physics and hot machine shop HVAC system
VHTR	Very High Temperature Reactor
VIC	Vienna International Center (where IAEA is located)
VLJ	Nuclear power plant operational waste (Finnish: Voimalaitosjäte)
VLJ Repository	Disposal facility for low and medium level operational waste arising at the Olkiluoto nuclear plant
VR	Virtual Reality
VRML	Virtual Reality Modeling Language
VRS	radwaste building HVAC system
VTS	turbine building ventilation system
VTT	Technical Research Center of Finland (Valtion teknillinen tutkimuskeskus)
VVER	Russian pressurized light-water reactor
VVM	Environmental Impact Statement (Norwegian: Vurderinger af virkninger påmiljøet)
VWS	central chilled water system
VXS	annex/auxiliary buildings non-radioactive HVAC system
VYS	plant hot water heating system
VZS	diesel generator DG building heating and ventilation system
WANO	World Association of Nuclear Operators
WAP	Wireless Application Protocol
WATRP	Waste management Assessment and Technical Review Program (IAEA)
WCAP	Westinghouse Commercial Atomic Power (report)
WCOBRA/TRAC	Westinghouse large break LOCA and long term cooling computer analysis code
WDS	Waste Documentation System
WDT	water distribution tests
WEC	World Energy Council
WENRA	Western European Nuclear Regulators Association
WG	water gauge
WG	Weapon Grade
WGOTHIC	Westinghouse-GOTHIC analysis code
WGS	gaseous radwaste system
WHO	World Health Organization
WIN	Women In Nuclear
WLS	liquid radwaste system
WMD	Weapons of Mass Destruction
WMO	World Meteorological Organization
WNA	World Nuclear Association
WNTI	World Nuclear Transport Institute
WNU	World Nuclear University
WOG	Westinghouse Owners Group
WPS	Warm Pre-Stress
WRC	Welding Research Council
WRE	Whiteshell Research Establishment
WRS	radioactive waste drain system
WSS	solid radwaste system
WTO	World Trade Organization
WWS	waste water system
YDINO	Finnish gaussian short-range meteorological dispersion model
YVA	Environmental Impact Assessment, Finland (Ympäristövaikutusten arviointi)
YVL	Finnish safety guidelines for nuclear power plants (Ydinvoimalaitos)
ZOS	onsite standby power system
ZPA	zero period acceleration