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Nuclear Safeguards Education Portal

Spent Nuclear Fuel Safeguards

Active interrogation: Radiation detection with active interrogation involves shooting a beam of radiation (photons or neutrons) into the items of interest. Then the detectors used for passive detection are employed to register any radiations that are emitted due to the bombardment. More.
Advanced Experimental Fuel Counter (AEFC): The advanced experimental fuel counter (AEFC) is used for characterization of spent fuel from research reactors stored under water. More.
Advanced Safeguards Methods (Next Generation Safeguards Initiative): The primary goals of the spent fuel NDA program was to improve the ability to determine plutonium quantity and to detect partial defects (missing fuel rods) in spent fuel assemblies. More.
AFR storage sites: ‘away from reactor’ fuel storage facilities More.
Burnup: Burnup is a way to measure how much uranium is burned in the reactor. More.
CANDU Bundle Verifier (CBVB): The CANDU bundle verifier (CBVB) includes a highly collimated and shielded CdTe detector. More.
CANDU core discharge monitor (VIFC): The CANDU core discharge monitor (VIFC) is a typical unattended monitoring system operating in an inaccessible area. It detects irradiated fuel upon discharge from the core face of a CANDU reactor. More.
CANDU spent fuel bundle counter (VIFB): The CANDU spent fuel bundle counter (VIFB) is an unattended system that monitors a strategic location in the spent fuel bundle pathway of an on-load refuelled power reactor. More.
CANDU VIFM 'yes/no' monitor (VIFD): The CANDU VIFM ‘yes/no’ monitor (VIFD) determines if any irradiated fuel has been discharged through access ports that are not part of the normal discharge path. More.
CANDU VXI integrated fuel monitor (VIFM): The VXI integrated fuel monitor (VIFM) is used at CANDU facilities to monitor and count discharged fuel bundles. More.
Cap seal (CAPS): The metal cap seal has been in service for more than 30 years and is extensively used for sealing material containers, material cabinets and IAEA safeguards equipment. More.
Cask radiation profiling system for dry storage casks (CRPS): The cask radiation profiling system (CRPS) is used to re-verify the presence of spent fuel in a dry storage cask following a break in the continuity of knowledge (i.e. a gap in surveillance and seals). More.
Cerenkov radiation: Cerenkov radiation (light) is produced when charged particles pass through water (for example) faster than the phase velocity of light in water. More.
Cerenkov radiation detection: A technique used to verify the irradiation of nuclear fuel or materials in a storage pool or other potential irradiation zones. More.
Cf-252 Interrogation with Prompt Neutrons (CIPN): CIPN uses fission chambers in polyethylene in a Fork detector-like configuration with active interrogation from a Cf-252 neutron source to determine the total fissile content of a spent nuclear fuel assembly. More.
Compton Dry Cask Imaging System (CDCIS): The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. More.
Containment and surveillance (C/S): The use of C/S measures is aimed at verifying information on movement of nuclear or other material, equipment and samples, or preservation of the integrity of safeguards relevant data. More.
Continuity of knowledge: A detailed record of activities taking place in a safeguarded area More.
Cooling time: The time in days since the final irradiation cycle experienced by the fuel. More.
Delayed Gamma (DG): Similar to the delayed neutron measurements, delayed gamma techniques utilize measurements of beta-delayed isotopes that are produced in fission events. More.
Delayed Neutrons (DN): The DN system was integrated with the DDA to make use of greater sensitivity of delayed neutron count rate to U-235 concentration More.
Destructive analysis: An assay of a material in which the physical form of the sample is destroyed. More.
Differential Die-Away (DDA): The DDA method uses the difference in die-away (or decay) time between epithermal (medium energy) and thermal (low energy) neutrons to characterize the amount of fissile material in spent nuclear fuel assemblies. More.
Differential Die-Away Self-Interrogation (DDSI): The DDSI system exploits a very slight difference in the arrival time of neutrons from spontaneous fission in spent fuel Curium and neutrons from induced fission in spent fuel fissile material. More.
Direct use material: Nuclear material that can be used for the manufacture of nuclear explosive devices without transmutation or further enrichment. More.
Diversion: The undeclared removal of declared nuclear material from a safeguarded facility, the use of a safeguarded facility in the introduction, production or processing of undeclared nuclear material, or the use of safeguarded material to further any military purpose. More.
Diversion scenario: A possible path for the diversion of fissile material for a nuclear weapons program. More.
Dry cask storage: Dry cask storage allows spent fuel that has already been cooled in the spent fuel pool for at least one year to be surrounded by inert gas inside a container called a cask. More.
Electronic optical sealing system (EOSS): A type of electronic seal commonly used by the IAEA. More.
Fork detector irradiated fuel measuring system (FDET): Detector system that straddles light water reactor fuel assemblies with pairs of neutron and γ-ray detectors. Gross γ ray and neutron intensities and ratios of intensities can give specific information on the fuel assembly More.
Fuel Transfer Video (FTPV): Facility specific CCTV system used at fuel transfer ponds. More.
IAEA timeliness detection goal: The target detection times applicable to specific nuclear material categories. More.
Independent spent fuel storage installation (ISFSI): A complex designed and constructed for the interim storage of spent nuclear fuel and associated materials. More.
Indirect use material: All nuclear materials that aren’t included in direct use materials. Materials that require processing to or can’t create a nuclear explosive device. More.
Irradiated fuel attribute tester (IRAT): The irradiated fuel attribute tester (IRAT) is a small, lightweight CdZnTe based detector that can be suspended from a spent fuel pond bridge and used to differentiate irradiated non-fuel items from irradiated fuel items that are stored in spent fuel storage ponds. More.
Irradiation (or power) history: The specific power or energy released per unit time experienced by the fuel assembly. More.
JRC CANDU sealing system (JCSS): The JRC CANDU sealing system (JCSS) and the ultrasonic sealing bolt (USSB) are systems for underwater sealing that use ultrasonically verifiable sealing bolts. More.
Material Balance Area (MBA): An area in a facility where the nuclear material quantification can take place and the inventory of said materials can be accounted for in between movement around or from the facility. More.
Material category: Categorization of nuclear material according to its irradiation status and suitability for conversion into components of nuclear explosive devices. Irradiated direct use, un-irradiated direct use, indirect use material are the three categories. More.
Material form: Classification of nuclear material according to its physical form; material can be either in item form or in bulk form. More.
Mobile monitoring system for container transport (MMCT): The mobile monitoring system for container transport (MMCT) monitors the transfer of spent fuel via railcar and consists of radiation monitoring, video surveillance and GPS location equipment, and smart power management. More.
Mobile Unit for Neutron Detection (MUND): The mobile unit for neutron detection (MUND) is an all in one neutron detection system for data collection and storage that is capable of running on battery power. More.
MVDS: The MVDS is a type of dry cask storage for nuclear fuel. More.
Neutron and gamma attribute tester (NGAT): The neutron and gamma attribute tester (NGAT) is a compact, universal instrument used for underwater verification of spent fuel assemblies, fresh MOX fuel assemblies, and open or closed containers holding various irradiated and non-irradiated materials including non-fuel items. More.
Next Generation of surveillance system (NGSS): The NGSS provides the complete surveillance infrastructure needed to make use of optical image and equipment state of health data to assist in the drawing of safeguards relevant conclusions. More.
Non-destructive assay: A wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. More.
Partial Defect Detector (PDET): The Partial Defect Detector (PDET) is an instrument associated with a new measurement methodology that uses multiple tiny neutron and gamma detectors in a form of cluster and high precision driving system to obtain underwater radiation measurements inside a Pressurized Water Reactor (PWR) spent fuel assembly. More.
Passive interrogation: Radiation detection with passive interrogation uses detectors to register the radiation naturally emitted by a material. More.
Passive Neutron Albedo Reactivity (PNAR): PNAR uses reflected neutrons from a spent nuclear fuel assembly to induce fission and characterize total fissile content More.
Safeguards MOX Python System (SMOPY): The safeguards MOX python (SMOPY) device combines gross neutron counting with low resolution γ spectroscopy to characterize any kind of spent fuel. More.
Seals: An indicator that allows personnel to be notified if a device that is used to contain nuclear materials has been accessed by un-authorized personnel. More.
Self-Interrogation Neutron Resonance Densitometry (SINRD): SINRD relies on solely on the neutron emissions of the spent fuel without any active interrogation. More.
Significant quantity: The amount of nuclear material that would allow the possible manufacturing of a nuclear explosive device. More.
Silo Entry Gamma Monitor (SEGM): The silo entry gamma monitor (SEGM) monitors the loading of dry storage containers into a final silo storage location. More.
Source material: The term "source material," means uranium containing the mixture of isotopes occurring in nature; uranium depleted in the isotope 235; thorium; any of the foregoing in the form of metal, alloy, chemical compound, or concentrate; any other material containing one or more of the foregoing in such concentration as the Board of Governors shall from time to time determine; and such other material as the Board of Governors shall from time to time determine. More.
Special fissionable material: The term "special fissionable material," means plutonium-239; uranium- 233; uranium enriched in the isotopes 235 or 233; any material containing one or more of the foregoing; and such other fissionable material as the Board of Governors shall from time to time determine; but the term "special fissionable material," does not include source material. More.
Spent fuel attribute tester (SFAT): The spent fuel attribute tester (SFAT), consisting of a multichannel analyser electronics unit and a NaI or CdZnTe detector, is used for taking measurements from the top of a fuel assembly as it sits in the storage rack More.
Spent fuel coincident counter (SFCC): The spent fuel coincident counter (SFCC) is an underwater neutron coincident counter for the verification of operator declared plutonium content in canned fast breeder reactor spent fuel. More.
Spent fuel pool: Involves storing spent fuel assemblies under at least 20 feet of water, which provides adequate shielding from the radiation for anyone near the pool. More.
Spent fuel signatures: Spent fuel signatures are the characteristics of spent nuclear fuel that can be used to verify its presence, identity, integrity, and nuclear material content. More.
Spent nuclear fuel: Nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant) and subsequently removed. More.
Transportation cask: A shipping container that is used to transport active nuclear materials between reactor and storage/reprocessing sites. More.
Ultrasonic sealing bolt (USSB): The JRC CANDU sealing system (JCSS) and the ultrasonic sealing bolt (USSB) are systems for underwater sealing that use ultrasonically verifiable sealing bolts. More.
Unattended Monitoring: A type of application that is able to run without direct inspector intervention, such as a part of the C/S measurements taken. More.
Unattended Spent Fuel Monitor (UFSM): The unattended fuel flow monitor (UFFM) and unattended spent fuel monitor (UFSM) monitor the movement of fresh fuel assemblies to the reactor (for those reactors utilizing MOX - mixed oxide fuel that contains plutonium - such as breeder reactors and LWRs on a MOX cycle), spent fuel assemblies from the reactor to the fuel storage pond, and spent fuel assemblies out of the storage pond. More.
Underwater television (UWTV): The portable underwater television (UWTV) system is mainly used for verifying bundles in spent fuel ponds of CANDU type reactors. More.
Variable coding sealing system electronic seal (VACOSS-S): The VACOSS seal is a type of electronic seal used by the IAEA. More.