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[en] With the continuous development of China's nuclear power projects in recent years, spent fuel has gradually entered a long-term storage stage, in which wet storage is the main way. The supervision of spent fuel storage facilities is becoming increasingly important. As China's nuclear safety regulatory system in this area is not complete, and there are few examples to refer to, it is urgent to explore and clarify the important concerns. Based on China's nuclear safety regulatory requirements and related regulatory experience of such facilities, this paper puts forward some suggestions for reference. (author)
[en] The use of enrichment higher than 5% will impact all the steps of the fuel cycle except for mining and conversion. • ENRICHMENT: modifications of plant and storage facilities. • TRANSPORTATION (1): currently authorization up to 5% enrichment, class A (30B cylinder). Over 5% requires new package; class B. • FUEL FABRICATION: redesign and relicensing required for UF6 to UO2 conversion, pelletization, and assembly fabrication. • TRANSPORTATION (2): new package required to transport fresh fuel assembly from the FF facility to the reactor. • REACTOR: change of fission gas generation - re licensing. • TRANSPORTATION (3): spent fuel container. • STORAGE / TREATMENT.
[en] Interim away from reactor (AFR) storage facilities may be located at the reactor site using the complete infrastructure and personnel of the nuclear power plant for their operation or at a separate site using their own infrastructure as a standalone and independent facility. With the final shutdown and decommissioning of the nuclear power plants is this infrastructure for facilities at the reactor site no longer available. It becomes necessary to install a separate infrastructure and a separate team for the facility operation to become a standalone and independent facility. This paper deals with AFR storage facilities without own infrastructure and gives an overview as a checklist on the necessary considerations to become a standalone and independent storage facility. (author)
[en] Fuel is periodically replaced in nuclear power plants (NPPs), generating “Spent Nuclear Fuel” (SNF). The paper attempts to calculate the relationships between the costs and the sizes of SNF storage facilities. This is done by estimating reduced-form equations based on publicly available data. The values reported here should not be considered as the only possible outcomes; they are used here to understand relative NPP owner economic incentives. The paper finds that once the NPP has been decommissioned, and only the on-site dry storage remains, there might not be a cost reason (from the point of view of the NPP owner/operator) to move the SNF to centralised facilities. However, there is a consensus that centralised facilities (a) would be more safe and secure than dispersed on-site storage locations, (b) would facilitate final disposal, and (c) can reduce the risks perceived by local communities near SNF storage facilities. (author)
[en] When radiopharmaceuticals are procured, it is tempting to select based on the cost of the product. In the case of Lutetium-177 for radiopharmaceutical therapy, this may have considerable practical consequences. The radionuclide can be produced using a direct (NCA Lu-177) or an indirect method (CA Lu-177), yielding products with different specific activities and different levels of contamination with Lu-177m, which has a half-life of 160 days. We asked ourselves what the implications for waste management would be if we switched from NCA to CA Lu-177. Data from 73 Lu-177 therapy doses prepared and dispensed in our hospital were reviewed. Doses were individually prepared, starting with approximately 7.4 GBq Lu-177. The activity of waste from the radiosynthesis procedure (production waste, P) and from dispensing and administration of the patient dose (dispensing waste, D) were calculated. These values were used to estimate potential levels of Lu-177m in waste. Waste P contained an average of 885 ± 336 MBq and waste D 183 ± 106 MBq Lu-177. Assuming that 0.05 kBq Lu-177m is present per 1 MBq CA Lu-177 (Bakker et al, 2006), the waste contents of the longer-living isotope would be 44 kBq and 9 kBq respectively (Table 1). In South Africa, radioactive substances with activities less than 100 Bq/g and total activity less than 4 kBq can be disposed as normal waste. On the day of synthesis and administration, all our production waste would have exceeded the 4 kBq limit, while only 10 lots of dispensing waste would fall below that level. In our worst-case scenario, even if a facility were to receive a ready-to-use Lu-177 radiopharmaceutical containing Lu-177m, waste from dispensing may have to be stored almost 2 years before disposal. In this study we only considered waste and we excluded patient excreta. For radiosynthesis and therapy, other aspects of the radionuclide, like the effect of low specific activity, should also be carefully considered. In conclusion, the decision regarding Lu-177 procurement should not be based on cost only. If long-living contaminants are likely in a radiopharmaceutical product, waste management and storage facilities will be an important consideration. (author)
[en] The minesite Konrad is going to be converted into a final storage facility for solid or consolidated radioactive waste with negligible heat generation. To investigate the flow in the exhaust channel "chimney" a test facility with 1:5 scaled mockup was built. 2O-PIV measurement technology was used to analyze the flow at the envisaged sample taking point. The main purpose of the tests was to forecast if the different criteria for homogenous flow defined by DIN ISO 2889 could be met. Two test parameters have been examined: (total) air volume flow and particle size. Only one of three investigated criteria was passed for all particle sizes and volume flows. Further investigations into adaptions of the exhaust channel "chimney" are necessary to fulfill all requirements for homogenous flow at the sample taking spot for all particle sizes and all (normal) operation status.
[en] In the United States, an approach to manage the aging of spent fuel dry storage systems was created by contributions from the regulatory body, storage facility owners, cask vendors, and the engineering community. The U.S. regulations for storing spent fuel beyond the first approved storage term require aging management activities to ensure that materials degradation will not adversely affect the safe storage of the spent fuel. Several guidance documents provide recommendations for complying with this regulation. The U.S. Nuclear Regulatory Commission (NRC) and the Nuclear Energy Institute (NEI) developed NUREG-1927 and NEI 14-03, respectively, to describe methods to identify the components that support a safety function, to evaluate the aging mechanisms could affect safety, and to establish aging management activities. The NEI guidance also introduces a new system to share operating experience through an Institute of Nuclear Power Operations database. The NRC also developed NUREG-2214 to identify the credible materials aging mechanisms for several cask designs used in the United States. NUREG-2214 also provides example aging management programs that may be used to effectively manage aging. Those programs rely, in part, on consensus codes and standards for monitoring and inspection guidelines, such as American Concrete Institute codes and the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Finally, to provide oversight of aging management activities, the NRC is developing internal procedures to evaluate, through inspection, the storage facilities’ performance of their aging management programs. Lessons learned from NRC Temporary Instruction TI 2690/011 will inform the development of a new NRC inspection procedure. (author)
[en] On March 2019, the regulatory body of Japan, NRA, issued new regulations on dual purpose cask (DPC) for dry storage of spent fuel on the site, along with the licensing process of design certification on DPC. The requirements ensure consistency with those for the interim storage facility off the site and with transport regulations. (author)
[en] The Pakistan nuclear power generation capability is progressing rapidly. Currently five Nuclear Power Plants are in operation and two Nuclear Power Plants are under construction. Pakistan is committed towards safe, secure and sustainable management of spent fuel generated from its Nuclear Power Plants operation. The spent fuel so far generated is stored at reactor spent fuel pools under water. These spent fuel pools have limited storage capacities and are not designed to accommodate spent fuel generated from lifetime operation of Nuclear Power Plants in Pakistan. Consequently, Pakistan has decided to develop spent fuel dry storage facilities for storage of spent fuel for extended periods till ultimate decision regarding spent fuel management is taken. The paper discusses the experience of managing the spent fuel at reactor pools and development process of spent fuel dry storage facilities in Pakistan. (author)
[en] According to the Swiss waste management policy, spent nuclear fuel is planned to be disposed in a deep underground repository. Prior to final disposal, spent nuclear fuel is stored at reactor sites and in a centralized dry storage facility. Since the operation dates of the final repository are unknown, extended periods of interim storage have to be considered. A research program to investigate the fuel rod integrity during long-term dry storage has recently been launched at Paul Scherrer Institute. In the context of the project, fuel rod performance simulations will be carried out with the code Falcon. Until now, an extensive literature survey concerning current trends in dry storage modelling has been written and first developments of Falcon's capabilities towards dry storage modeling have been made. In this work, Falcon has been modified by implementing a long-term cladding creep model. The original and upgraded versions of Falcon have been used to simulate a demonstration case consisting of the base irradiation, wet storage, drying and dry storage. Results obtained with both versions have shown an important difference in the cladding hoop creep which justifies implementation of the new creep model.