Introduction and Executive Summary
The Nuclear Fuel Cycle
This chapter gives an overall picture of the philosophy that is adopted to ensure high standards of safety in the fuel cycle. All nuclear fuel cycle facilities are subject to regulatory control that requires installations to be designed, constructed, commissioned, operated, and decommissioned with due regard to the safety of workers and to the general public.
This chapter contains a discussion of the general safety matters associated with the fuel cycle, including hazards of both radiological and non-radiological nature. Malevolent actions can be oriented towards nuclear fuel cycle facilities or radioactive matters transportation, the same way as they could be oriented towards any other dangerous product, activity or facility such as chemical or explosives factories. Protective measures against such actions are not specific to nuclear facilities, they are dealt with by specialists and their details are kept confidential.
Safety of the Front End of the Fuel Cycle
The mining and milling of uranium do not have the same level of potential safety problems that are associated with operation of nuclear reactors and other fuel cycle facilities. The uranium mines do have the same safety and environmental issues as other mines in addition to the precautions required to deal with the radioactivity of the ore.
Safety of the Spent Fuel Storage
Several technologies are being used for the storage of spent fuel at reactor (AR) sites and at sites away from reactors (AFR) (Figure 6.1). Both wet (pool) storage facilities and dry storage facilities (buildings and containers) are used on a commercial scale.
Safety of Fuel Reprocessing
Spent fuel from NPP has been reprocessed on an industrial scale for about 40 years, by separating the recyclable fissile material from the unusable fission products contained with them. The separation technique generally adopted is liquid-liquid extraction, using nitric acid for the aqueous phase and tributyl phosphate (TBP) for the solvent of the organic phase, following the PUREX process.
Safety of the Management of Radioactive Waste
The management of radioactive waste requires the adoption of a certain number of policies and practices that share a common objective: the handling, interim storage, and disposal of radioactive waste with every necessary safety precaution to prevent any undue radiation of people or contamination of the environment over both the short and the long term.
Safety of On-Site Waste Storage
Vitrified waste must be stored during the period between solidification and their disposal. This period can last up to several decades, mainly to enable the level of activity and the production of heat to decrease to suitable levels for disposal.
Safety of Decommissioning of Nuclear Facilities
Decommissioning is the final stage in the life-cycle of a nuclear facility. The final act of shutting down the facility should be to remove the radioactive materials in process and the radioactive waste from normal operations. Subsequently, during decommissioning, the remaining radioactivity must be safely removed from the facility through decontamination and dismantling, so that the facility can be demolished, or refurbished for re-use.
Safety of the Transport of Radioactive Materials
Specific safety regulations are well-developed and harmonised internationally. Accident situations have been taken into account from the beginning and the transport regulations are framed so that unacceptable radiation exposures should not occur from either radioactivity release or shielding loss even in the case of severe accidents. Actual packages are designed to remain safe in the specified regulatory conditions of rain, stacking, collision, fire, and immersion.
Safety Records of Fuel Cycle Facilities
Collective dose, when provided hereafter for an individual facility, may vary considerably from year to year, depending on many parameters. Its general trend is provided as an indicator of the radiation protection efficiency, that is to say the ability of the operator to control radiation spread through efficient operation and maintenance. It should not be used in such case as an health indicator.
The decade since the previous edition of this report (last issued in 1993) has been a period of relative stability, with no important increase in the number of nuclear power plants. The main reason is the past overestimation of needs, which led to general overcapacity. Political considerations based on public acceptance problems have certainly also been an aggravating factor.
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