Nuclear fuel cycles closed

Fig. 1. Schematic illustration of the ideal closed nuclear fuel cycle (NRC 2003). In real practice, the reprocessing capacity does not match the generation rate of the spent nuclear fuel. Thus, the excess SNF must be placed in interim storage or disposed of in a geological repository. Under normal circumstances, the SNF will be in interim storage for just a few years. Also, note that excess material from nuclear weapons, e.g.. highly enriched 235U and 239Pu, can be blended down to lower concentrations and used as a reactor fuel.

Vlasov, V. I., Kedrovsky, O. L., Polyakov, A. S. Shishtchitz, I. Y. 1987. Handling of liquid radioactive waste from the closed nuclear fuel cycle. In Back End of the Nuclear Fuel Cycle Strategies and Options. IAEA, Vienna, 109-117. 

Collins, E.D., Felker, L.K., Benker, D.E., Campbell, D.O. 2008. Closed nuclear fuel cycle technologies to meet near-term and transition period requirements. ATALANTE 2008 Nuclear Fuel Cycles for a Sustainable Future, May, Montpelher, France. 

Recently much attention has been given to the accelerator driven systems, burning in inert matrices, and the use of thorium to burn plutonium. The concept of a closed nuclear fuel cycle was traditionally considered as transmutation (burning) of only plutonium and recycled uranium, with minor actinides (neptunium, americium, curium) destined for final geological disposal. But as time goes on, a new understanding is emerging reduction of the quantity of actinides would ease requirements for final repositories and make them relatively less expensive. 

The problem of NP fuel supplying could be solved by FR operating in closed nuclear fuel cycle (NFC) and enabling to involve effectively uranium-238 into power generation. 

Introduction of fast reactors with a closed nuclear fuel cycle into the nuclear power industry can radically change the current approaches to fuel supply and management of long-lived radwaste. 

The conceptual design of the advanced reactor plant BN-1600 was completed in 1992, in full compliance with the up-to-date requirements for safety and economic efficiency of the new generation NPPs. It is expected that this design can be realized in Russian Federation not earlier than 2020, taking into account the fact that in the near future the fast reactor development programme in this country will be primarily focused on construction of the pilot BN-800 reactors, and creation of the closed nuclear fuel cycle production plants. This phase is of exceptional importance for the subsequent development of fast reactors and should precede their wide incorporation into the nuclear power park. 

For the addressed concepts of small reactors without on-site refuelling. Chapter 5 reviews the fuel cycle options and associated institutional issues, provides an assessment of material balance characteristics in once-through and closed fuel cycles, and outlines the possible role of small reactors without on-site refuelling in making a transition from open to closed nuclear fuel cycle. This chapter also summarizes the features of small reactors that could facilitate their deployment with outsourced fuel cycle services. 

Possible role of small reactors without on-site refuelling in the transition from an open to a global closed nuclear fuel cycle... 

Improvements in the nuclear fuel and fuel cycle of the WER-1000 reactors realization of a closed nuclear fuel cycle ... 

In the next phase, spent fuel from the 4S or other reactors including LWRs could be reprocessed using pyro-process technology developed at the Argonne National Laboratory (ANL, USA) and/or CRIEPI (Japan). In this phase, plutonium and MA recovered from spent fuel could be used as fresh fuel for the 4S. Here, a centralized reprocessing plant would be preferable for the 4S because each 4S plant is a small distributed power station and a collocated reprocessing like in the IFR seems inappropriate for this type of power stations. To put it short, in the next phase, the 4S would be operated in a closed nuclear fuel cycle. 

Being a fast reactor with a breeding ratio of-1.0016, the RAPED could also contribute to the effective use of uranium resources, once a closed nuclear fuel cycle is established. 

The capability of fissile self-sustainable regime (core breeding ratio 1) in a closed nuclear fuel cycle with mixed uranium-plutonium fuel (oxide or nitride) ... 

In a more distant future, it will be necessary to change to an entirely closed nuclear fuel cycle. The time period for this change would be defined by the industrial development of economically effective spent fuel reprocessing technologies that should also be acceptable from the standpoint of non-proliferation and radioactive waste minimization. 

All operations with fuel are performed in a centralized way within the nuclear park. A closed nuclear fuel cycle where separation and transmutation are performed to ensure an acceptable balance between the inflow and the outflow of radiotoxicity is applied, see Fig. XXV-5. 

The standard fuel cycle option for the CHTR would depend upon the technology development for reprocessing of TRISO coated particle fuel and fuel compacts. In case of the development of a reprocessing technology, a closed nuclear fuel cycle option would be adopted. Fresh fuel for the reactor would be made from and Th recovered from the spent fuel. Alternately, it would be a once though fuel cycle without reprocessing. The objective then would be to achieve the highest possible fuel bum-up. 

Being capable to operate in a self-sustainable regime on nuclear fuel or as breeders, the liquid metal cooled SMRs are usually associated with further stages of nuclear power, when the deficiency of natural fissile isotopes may facilitate decisions on closed nuclear fuel cycles. The meeting addressed only lead and lead bismuth cooled innovative SMRs, and the summary of the design approaches is as follows ... 

The R D performed has demonstrated technical feasibility and potential economic competitiveness of the SVBR-75/100 reactor installations for nuclear power systems of both near and far future. The modular structure of NSSS of a power unit with SVBR-75/100 reactor installations makes it possible to reduce the NPP construction period and, in the future, to make a transfer to the standardized design of power units of different capacity on the basis of the serially produced standard modules offering a broad spectrum of inherent safety features. Such approach will assure competitiveness of the NPPs not only in electricity markets but in investment markets as well. Power units with SVBR-75/100 could be used in both developed and developing countries. For SVBR-75/100 it is possible to use different types of fuel and to operate reactor in different fuel cycles, preferably the ones that turn to be more efficient at certain moments of nuclear power evolution. When operating under a closed nuclear fuel cycle, it is possible to assure fuel self-supply regime or to provide a small breeding. The SNF of thermal nuclear reactors may be utilized as a make-up fuel for SVBR-75/100. 

The recovery of U and Pu in the closed nuclear fuel cycle usually produces an high level waste (HLW) stream containing high concentration of fission/activation products (e.g., U, Pu, Am, Eu, Sr) and process/structural materials (Fe, Ni, Cr, etc.). This concentrated HLW is typically submitted to immobilization in glass/ceramic matrices, followed by their disposal in geological repositories. Considering the half-lives of the fission products (in the range of hundred-millions years) this solution result is unsustainable. The treatment of HLW by SLM represents a possible alternative. 

All liquid metal cooled SMRs are designed to operate in a closed nuclear fuel cycle providing for the use of non-aqueous reprocessing methods. The designs of KALIMER, MDP and PEACER make use of the ternary U-Pu-Zr or U-TRU-Zr fuel and pyro-metallurgical reprocessing. The RBEC-M and the Medium Scale Lead-bismuth Cooled Reactor are nitride fuel reactors. The BMN-170 offers flexibility in the selection of fuel with either oxide, or nitride, or metallic fuel being applicable. 

High conversion or fuel breeding and operation in a closed nuclear fuel cycle, which could ensure a self-sustainable operation mode on fissile materials (with the breeding ratio BR -1.05) or the expanded breeding (BR>1) to produce fissile materials necessary for other, non-breeder reactors present in the system. 

The designers of the RMWR and the AHWR denote closed nuclear fuel cycles as basic. The technical features mentioned in conjunction with proliferation resistance are as follows ... 

A closed nuclear fuel cycle is to be used for the AHWR reactor. Thorium, and plutonium... 

AHWR is designed to operate in a closed nuclear fuel cycle, and the U content in demands a remote and automated production of fuel. A closed fuel cycle involving the remote refabrication of fuel is considered an important attribute of several of the next generation nuclear fuel cycles now being internationally stipulated. With these stipulations, the incremental cost for a planned future incorporation of dry reprocessing in the AHWR fuel cycle is expected to be either low or nil. 

A closed nuclear fuel cycle is to be used for the KALIMER. U, TRUs, and some fission products will be recovered from the spent fuel and recycled. A schematic of the KALIMER fuel cycle is shown in Fig. XX-2. 

This closed nuclear fuel cycle strategy drove the development of a semicommercial SFR BN-350 model. While the BN-350 was under construction, the USSR started designing a larger BN-600 in parallel. Many of the lessons learned from the BN-350 demonstration project were used in the commercial design of the BN-600 (Fig. 12.1). 

Besides power generation and eventual replacement of the BN-600, the BN-800 will be used to demonstrate enhanced safety features and principles that are to be implemented in the next generation of commercial SFRs. It is planned to eventually use the plant as part of the closed nuclear fuel cycle with mixed oxide (MOX) or nitride fuel. The reactor core is planned to be recycled 20 times over the course of 40 years with 730 fuel cycle length (equivalent full power day, EFPD) fuel campaigns. The facility will also play an important role in obtaining data on the economic performance and approaches to operating cost optimization as well as the advanced fuel... 

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