Fuel reprocessing methods

Due to the progress in technology and development of intensive fuel reprocessing methods, applying centrifugal extractor batteries, there is a strong demand for the method to observe closely some process facilities from the criticality point of view. This paper presents experiments with on-line, anomalous reactivity prediction of spme facilities, providing alarm and possible plant protection functions. 

After launching such factory, the cost of the core will only be determined by the operating costs of spent fuel reprocessing and the costs of fuel assembly fabrication. If the pyro-electrochemical fuel reprocessing methods developed by the State Scientific Centre of the Russian Federation Research Institute of Atomic Reactors (SSC RIAR) are used, the contribution of fuel costs to the cost of SVBR-75/100 will be even less than in the basic variant using a once-through cycle with the uranium dioxide fuel. This will make it possible to improve considerably the NPP competitiveness. The abovementioned approach to the construction of capacities for reprocessing and fuel assembly fabrication presumes that the owner of the NPPs would also be the owner of the fuel cycle factories. 

If decided, the standard fuel reprocessing method as used for VVER type reactors could be applied. In this, fuel reprocessing can be made centralized. 

The fuel reprocessing method similar to that applied to the VVER-440 reactors could be used. XII-1.6.3. Safety and reliability Safety concept and design philosophy... 

Research should continue on traditional separation methods. For example, there is a continuing need for more selective extraction agents for liquid-liquid and ion-exchange extractions. High-temperature processes that use liquid metals or molten salts as extraction agents should have potential in nuclear fuel reprocessing and... 

The two principal methods by which actinides may enter the body are inhalation and penetration through wounds. These two routes of entry are of obvious concern to those individuals working in nuclear fuel reprocessing plants. The principal route of entry by which most of the general public is likely to be exposed to the actinides could be expected to be via the food chain. However, Bennett (176) has indicated that inhalation of 239>(i) 240Pii is more important by a factor of 1000 compared to the uptake by ingestion in contributing to the body burden. 

AECL has evaluated some of the basic information and development requirements in some detail (24, 25) and has outlined the type of fuel recycle development program which would be required. It would involve research and development of thorium fuels and fuel fabrication methods, reprocessing, demonstration of fuel management techniques and physics characteristics in existing CANDU reactors and demonstration of technology in health, safety, environmental, security and economics aspects of fuel recycle. 

Shimada, T., Ogumo, S., Ishihara, N., Kosaka, Y., Mori, Y. 2002. A study on the technique of spent fuel reprocessing with supercritical fluid direct extraction method (Super-DIRECT method). J. Nucl. Sci. Technol. Suppl. 3 757-760. 

Holladay, D. W. A Literature Survey Methods for the Removal of Iodine Species from Off-Gases and Liquid Wste Streams of Nuclear Power and Fuel Reprocessing Plants with Emphasis on Solid Sorbents. 0RNL/TM-6350, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 1979. 

Equipment for the reprocessing of irradiated fuel by methods other than solvent... 

Despite of some technical and process limitations, membrane techniques are very useful methods for the treatment of different types of effluents. They can be applied in nuclear centers processing low- and intermediate-level liquid radioactive wastes or in fuel reprocessing plants. All the methods reported in the chapter have many advantages and can be easily adapted for actual, specific needs. Some of them are good pretreatment methods the other can be used separately as final cleaning steps, or can be integrated with other processes. Membrane methods can supplement or replace techniques of distillation, extraction, adsorption, ion exchange, etc. Evaluation of membrane processes employed for liquid radioactive waste treatment is presented in Table 30.17. 

Apart from radioactive tritium separation from reactor atmosphere or off-gas, polymeric membranes can be applied for separation of noble gases produced by nuclear power plants and fuel reprocessing plants as an alternative to commonly used adsorption or low-temperature distillation methods. 

A full account of the problems considered in collecting, storing, and processing marine samples for transuranic analysis is given in the above-mentioned review (4). The specific methods discussed here were foimd effective at least for the transuranic analyses of seawater and sediments contaminated by global fallout, nuclear fuel reprocessing wastes, or nuclear power plant operation waste. In these cases, a preliminary acid treatment of the sample in the presence of suitable yield monitors seems to solubilize the transuranic elements and achieves isotopic equilibration between the yield monitor and sample. The yield monitors used were either Pu or sep qj. 238,239,240,24ip whereas Am was used for Am, 2 Cm, and by inference, Cf. In addition, it was convenient to use 50 mg of a lanthanide (neodymium) as a carrier for americium to purify the separated americium fraction. 

This Symposium has been organized about new concepts, new systems, and new developments in actinide separations methodology. Much of the work reported here is based on fundamental actinide chemistry developed since the Manhattan Project days. The chapters in this volume describe ion exchange, solvent extraction, precipitation, pyrochemical, photochemical, and other methods of actinide separations as well as application of these separation methods to power reactor fuel reprocessing and recovery of actinides from waste solutions. 

Aqueous reprocessing methods have been developed to effect an efficient and thorough separation of fissile elements from the contaminating fission products in spent fuel( l). While these processes may be altered to yield a proliferations-resistant product by coprocessing or by the addition of radioactive material that will contaminate the clean fissile material, it still is necessary to safeguard some of the process steps to ensure that material useful in nuclear weapons will not be diverted (3). The safeguard requirements and the ease of subversion of such provisions make many versions of the conventional processes subject to unacceptable proliferation risks. 

The pyrochemical coprocessing of spent nuclear fuel by the Salt Transport Process appears to be a potentially viable reprocessing method, not only as an "exportable proliferation resistant technology," but as a domestic reprocessing operation. All operations are nonaqueous and waste generation is in solid form, thus requiring no conversion from aqueous solutions to solids. 

A Nonaqueous Reprocessing Method for Thorium-Based Fuels... 

---