Nuclear power development in market conditions with use of multi-purpose modular fast reactors SVBR-75/100

This article presents an innovative nuclear power technology, based on the use of modular type fast-neutron reactors SVBR-75/100 having heavy liquid-metal coolant, i.e. eutectic lead–bismuth alloy, which was mastered in Russia for the nuclear submarines’ reactors. Reactor SVBR-75/100 possesses inherent self-protection and passive safety properties that allow excluding of many safety systems necessary for traditional type reactors. Use of this nuclear power technology makes it possible to eliminate conflicting requirements among safety needs and economic factors, which is particularly found in traditional reactors, to increase considerably the investment attractiveness of nuclear power based on the use of fast-neutron reactors for the near future, when the cost of natural uranium is low and to assure development of nuclear power in market conditions. On the basis of the factory-fabricated “standard” reactor modules, it is possible to construct the nuclear power plants with different power and purposes. Without changing the design, it is possible for reactor SVBR-75/100 to use different kinds of fuel and operate in different fuel cycles with meeting the safety requirements.     

Plutonium fuel and fuel elements for power reactors

Conclusions The use of plutonium in the fuel cycle during complex utilization of thermal and fast reactors in nuclear energetics permits solving the problem of ensuring nuclear fuel for a long period. Oxide uranium-plutonium fuel facilitates the development of technology of fast reactors and so far it is considered as the basic type of fuel. At the same time, oxide fuel cannot ensure the required rate of plutonium accumulation, in view of which the investigations of more efficient fuel and constructional materials become a pressing problem. The use of uranium-plutonium oxide fuel in thermal reactors requires improvements in the construction of fuel elements and organization of large-scale completely automatic production.Translated from Atomnaya Énergiya, Vol. 43, No. 5, pp. 412–417, November, 1977. Editors' Remarks. For the completeness of the discussion of the problem it is, of course, necessary to consider the possibility of using plutonium in fast and thermal reactors as done by the authors. However, it should be kept in mind that by its nuclear-physical parameters plutonium as a nuclear fuel is more suitable for use in fast reactors than in thermal reactors. The use of plutonium in thermal reactors can reduce the demands of natural uranium for the development of nuclear power in all by 10–15%, whereas its use in fast reactors reduces the demand for uranium by a factor of 10.All this indicates the feasibility of using plutonium only in fast reactors even if its accumulation is required over a certain period.     

Possibilities of BREST reactors and transmutation fuel cycle under conditions implementing modern plans for the development of nuclear power

The possible dynamics of the development of BREST-1200 fast reactor capacities after 2030 on the basis of plutonium and other actinides accumulated in the spent fuel of thermal reactors is examined. It is shown that by 2100 the power BREST reactors could be 114–176 GW, and subsequently they will develop as a result of their own breeding of plutonium. Calculations have shown that the rate at which BREST reactors are put into operation can be doubled by using enriched uranium obtained from natural uranium and regenerated spent fuel from thermal reactors. It is shown that the development of fast reactors with a closed fuel cycle solves the problem of transmutation of long-lived high-level actinides and makes it possible to implement a transmutation fuel cycle in nuclear power. __________ Translated from Atomnaya énergiya,Vol. 103, No. 1, pp. 21–28, July, 2007.     

Innovative nuclear technology based on modular multi-purpose lead–bismuth cooled fast reactors

Today's nuclear power is in the state of an intrinsic conflict between economic and safety requirements. This fact makes difficult its sustainable development.

One of the ways of finding the solution to the problem can be the use of modular fast reactors SVBR-75/100 cooled by lead–bismuth coolant that has been mastered in conditions of operating reactors of Russian nuclear submarines.

The inherent self-protection and passive safety properties are peculiar to that reactor due to physical features of small power fast reactors (100 MWe), chemical inertness and high boiling point of lead–bismuth coolant, integral design of the pool type primary circuit equipment.

Due to small power of the reactor, it is possible to fabricate the whole reactor at the factory and to deliver it to the NPP site in practical readiness by using any kind of transport including the railway.

Substantiation of the high level of reactor safety, adaptability of the SVBR-75/100 reactor relative to the fuel type and fuel cycle, issues of non-proliferation of nuclear fissile materials, opportunities of multi-purpose usage of the standard SVBR-75/100 reactors have been viewed in the paper.     

Self-consistent model of nuclear power and nuclear fuel cycle

Under discussion are such major aspects of the nuclear energy sector as cost effectiveness, nuclear and environmental safety of reactors and nuclear fuel cycle facilities, sustained fuel supply, and proven feasibility of a proliferation-resistant technology. These requirements can be met, for instance, by a two-circuit nuclear facility with an inherently safe fast reactor of the BREST type which is expected to produce electricity at a cost not higher than that at modern LWRs. Fuel supply to such facilities and to a relatively small number of thermal reactors with BR<1, could be provided by fast reactors using depleted uranium as makeup fuel and having a small breeding gain in the core (CBR≈1.05) and bottom blanket (full BR≈1.1). Use of a high-boiling metallic coolant (lead) affords deterministic nuclear, technical and environmental safety of the plants in design-basis and hypothetical accidents. Introduction of a transmutational NFC is viewed as one of the avenues to global environmental safety, when the equivalent activity of long-lived high-level waste is made lower or close to the activity of the source material going into energy production. With such a balance in place, nuclear power could be regarded, in a sense, as waste-free.     

CANDU堆先进燃料循环的展望

介绍ＣＡＮＤＵ堆的天然铀燃料循环以及最近开发的适合未来近期的先进燃料循环。高中子经济性,不停堆换料以及简单的燃料束设计,使得ＣＡＮＤＵ堆具有非常优良的燃料循环灵活性和多样性。     

Characterization of minor actinide mixed oxide fuel

The global nuclear energy partnership (GNEP) was created in order for ‘fuel-cycle supplier’ nations to provide assured supplies of nuclear fuel to ‘fuel-cycle customer’ nations. The customer nations would utilize the fuel for electricity generation and subsequently return it to the supplier nation after it is spent. This spent fuel would then be reprocessed by the supplier nation in order to recycle the actinide constituents, mainly uranium and plutonium, in advanced nuclear power reactors, and thus reduce waste volumes [1] and [2]. The International Atomic Energy Agency would control the nuclear materials. One of the thrust areas for the GNEP program is the development of these actinide bearing fuels for transmutation in a fast reactor.     

Proliferation-resistant fuel options for thermal and fast reactors avoiding neptunium production

Sustainable nuclear energy production requires reuse of spent nuclear fuel while avoiding its misuse. In the paper we assume that plutonium with sufficiently high content of the Pu-238 isotope (about 6% or more) and americium from spent nuclear fuel are proliferation-resistant. On the other hand, neptunium should be considered as material that is fissionable in a fast neutron spectrum and could be misused.We also assume that plutonium denatured by Pu-238 can be produced in nuclear reactors of, e.g. nuclear weapon states and used for fuel fabrication there or in multilateral reprocessing and re-fabrication centers as suggested by IAEA. Then the fabricated fuel can be utilized in nuclear reactors everywhere provided that the reactors may operate safely and the fuel remains proliferation-resistant after utilization. Options to meet these criteria are investigated in the paper for two reactor types: pressurized water reactors (PWRs) and fast reactors (FRs).In PWRs, the investigated fresh fuel compositions include denatured plutonium and depleted uranium mixed with a small amount of U-233, thorium and, optionally, with americium, presence of U-233 making the coolant void effect negative. In FRs, use of americium makes plutonium denatured, both for the burner (without fertile blanket) and breeder options. It is shown that the proposed design and fuel options are proliferation-resistant, the generation of neptunium being very low. Safety parameters are acceptable. Advanced aqueous or pyrochemical reprocessing for plutonium/thorium/uranium fuel and related fuel re-fabrication technology applying remote handling may become necessary to realize the considered fuel cycles.     

Conversion of high enriched uranium in thorium-232-based oxide fuel for light and heavy water reactors: MOX-T fuel

This paper discusses the possibility of using military high enriched uranium and plutonium in thorium oxide fuel for light and heavy water reactors (LWRs and HWRs). It is shown that such a fuel has several important advantages: (i) ²³⁹Pu and other long-living actinides are generated in quantities which are at least 100 times less than in conventional fuel; (ii) neutron emission is lower by a factor of more than 100; (iii) ²³³U is generated and burnt (the conversion factor for LWRs is 0.64–0.68 and for HWRs about 0.88); (iv) thorium is utilized and the total available amount of nuclear fuel is increased. The problem of non-proliferation of fissile material is also discussed and it is shown that the supervision of such fuel does not differ essentially from the supervision of low enriched uranium fuel with plutonium generation.     

Radiation Characteristics of Fuel and Wastes in the Uranium–Plutonium and Thorium–Uranium Fuel Cycle

The radiation characteristics of fuel cycles of various reactors – replacement candidates in the future nuclear power – are compared. Proceeding from the basic requirements (safety, fuel supply, and nonproliferation of fissioning materials), inherently safe fast reactors of the BREST type can be used as the basis for large-scale nuclear power. Thermal reactors, which can burn enriched uranium, thorium–uranium fuel, or mixed uranium–plutonium fuel with makeup with fissioning materials from fast reactors, will operate for a long time simultaneously with fast reactors in the future nuclear power. VVÉR-1000 and CANDU reactors are examined as representatives of thermal reactors; for each of these reactors the operation in various variants of the fuel cycle is simulated. It is shown that with respect to radiation characteristics of the fuel and wastes the thorium–uranium fuel cycle has no great advantages over the uranium–plutonium cycle.     

Plutonium management with thorium-based fuels and inert matrix fuels in thermal reactor systems

The plutonium that is produced by light water reactors worldwide is currently re-used to a limited extent. In the last century, the expected introduction of fast reactors and the associated need for large amounts of plutonium did not take place. The result is that worldwide a stockpile of excess plutonium has formed, which is the dominant contributor to the radiotoxicity of spent nuclear fuel for storage times from 10² to 10⁵ years. One option to reduce or stabilize the plutonium stockpile is to utilize this plutonium in advanced fuel types, such as thorium-based and inert matrix fuels. Because these fuels do not contain uranium, the plutonium consumption rate is very high. In this paper, the status of the fuel research and some recent developments are given.     

Use of weapons plutonium in VVÉR-1000 reactors

One scenario for using excess Russian weapons plutonium is to load it into VVéR-1000 reactors. It is proposed that up to 40% of the fuel assemblies with uranium fuel be replaced with structurally similar fuel assemblies with mixed uranium-plutonium fuel. The stationary regime for burning fuel has the following characteristics: the run time is about 300 or 450 eff. days, the yearly plutonium consumption reaches 450 kg, the neutron-physical characteristics are close to the corresponding regimes with uranium fuel. The nuclear safety criteria and the irradiation dose for workers handling fresh and spent mixed fuel remain within the limits of the normative values. The use of mixed fuel makes it necessary to upgrade certain systems at nuclear power plants. A substantial quantity of weapons plutonium can be loaded every year into VVéR-1000 reactors, effectively using the energy potential of this plutonium. __________ Translated from Atomnaya énergiya, Vol. 103, No. 4, pp. 215–222, October, 2007.     

The fusion breeder

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the U.S. fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the U.S. fusion program and the U.S. nuclear energy program. There is wide agreement that many approaches will work and will produce fuel for five equal-sized LWRs, and some approach as many as 20 LWRs at electricity costs within 20% of those at today's price of uranium ($30/lb of U₃O₈). The blankets designed to suppress fissioning, called symbiotes, fusion fuel factories, or just fusion breeders, will have safety characteristics more like pure fusion reactors and will support as many as 15 equal power LWRs. The blankets designed to maximize fast fission of fertile material will have safety characteristics more like fission reactors and will support 5 LWRs. This author strongly recommends development of the fission suppressed blanket type, a point of view not agreed upon by everyone. There is, however, wide agreement that, to meet the market price for uranium which would result in LWR electricity within 20% of today's cost with either blanket type, fusion components can cost severalfold more than would be allowed for pure fusion to meet the goal of making electricity alone at 20% over today's fission costs. Also widely agreed is that the critical-path-item for the fusion breeder is fusion development itself; however, development of fusion breeder specific items (blankets, fuel cycle) should be started now in order to have the fusion breeder by the time the rise in uranium prices forces other more costly choices.     

2020年前我国核燃料循环情景初步研究

根据我国核电现状和中短期发展规划,对2020年前我国核电规模提出了三种预测方案,并根据各种方案对压水堆电站的核燃料循环情景进行了计算。重点研究了压水堆核电所需的铀资源、分离功,卸出的乏燃料以及乏燃料中Pu和次要锕系元素(MA)的产生量。     

SVBR-100 module-type fast reactor of the IV generation for regional power industry

In the report the following is presented: basic conceptual provisions of the innovative nuclear power technology (NPT) based on modular fast reactors (FR) SVBR-100, summarized results of calculations of the reactor, analysis of the opportunities of multi-purpose application of such reactor facilities (RF) including export potentials with due account of nonproliferation requirements. The most important features of the proposed NPT analyzed in the report are as follows: (1) integral (monoblock) arrangement of the primary circuit equipment with entire elimination of the primary circuit pipelines and valves that considerably reduces the construction and assembly works period and coupling with high boiling point of lead-bismuth coolant (LBC) deterministically eliminates accidents of the LOCA type, (2) option for 100 MWe power and dimensions of the reactor provide: on the one hand, an opportunity to transport the reactor monoblock in factory-readiness by railway as well as other kinds of transport, on the other hand, core breeding ratio (CBR) exceeds 1 while MOX-fuel is used.The preferable area of application of RF SVBR-100 is regional and small power requiring power-units of electric power in a range of (100-600) MW, which could be used for cogeneration-based district heating while locating them nearby cities as well as for generation of electric power in a mode of load tracking in the regions with low network systems.     

Mononitride Fuel for Fast Reactors

Substantiation is given for the development of nuclear power based on inherently-safe fast reactors with a mononitride core. Fundamental studies and design work on the development of such reactors with lead (BREST-OD-300), lead–bismuth (SVBR-75/100), and sodium coolant (BN-800) are being performed. The development of nuclear power in our country is based on organizing a closed fuel cycle. The results of experimental investigations of the properties of mononitride fuel are correlated. Mononitride fuel meets all requirements for fast-reactor fuel.     

Transmutation missions for fusion neutron sources

There are a number of potential neutron transmutation missions (destruction of long-lived radioisotopes in spent nuclear fuel, ‘disposal’ of surplus weapons-grade plutonium, ‘breeding’ of fissile nuclear fuel) that perhaps best can be performed in sub-critical nuclear reactors driven by a neutron source. The requirements on a tokamak fusion neutron source for such transmutation missions are significantly less demanding than for commercial electrical power production. A tokamak fusion neutron source based on the current physics and technology database (ITER design base) would meet the needs of the spent nuclear fuel transmutation mission; the technical issue would be achieving ≥50% availability, which would require advances in component reliability and in steady-state physics operation.     

Utilization of spent PWR fuel-advanced nuclear fuel cycle of PWR／CANDU synergism

High neutron economy, on line refueling and channel design result in the unsurpassed fuel cycle flexi-bility and variety for CANDU reactors. According to the Chinese national conditions that China has both PWR and CANDU reactors and the closed cycle policy of reprocessing the spent PWR fuel is adopted, one of the advanced nu-clear fuel cycles of PWR/CANDU synergism using the reprocessed uranium of spent PWR fuel in CANDU reactor is proposed, which will save the uranium resource (-22.5%), increase the energy output (-41%), decrease the quantity of spent fuels to be disposed (-2/3) and lower the cost of nuclear poower, Because of the inherent flexibility of nuclearfuel cycle in CANDU reactor, and the low radiation level of recycled uranium(RU), which is acceptable for CANDU reactor fuel fabrication, the transition from the natural uranium to the RU can be completed without major modifica-tion of the reactor core structure and operation mode.It can be implemented in Qinshan Phase Ⅲ CANDU reactors with little or no requirement of big investment in new design. It can be expected that the reuse of recycled uranium of spent PWR fuel in CANDU reactor is a feasible and desirable strategy in China.     

Optimum utilization of nuclear fuel with gas and vapor core reactors

Gas and Vapor Core Reactors (G/VCR) are externally reflected and moderated nuclear energy systems fueled by stable uranium compound in gaseous or vapor phase. In G/VCR systems the functions of fuel and coolant are combined and the reactor outlet temperature is not constrained by solid fuel-cladding temperature limitations. G/VCRs can potentially provide the highest reactor and cycle temperature among all existing or proposed fission reactor designs. Furthermore, G/VCR systems feature a low inventory and fully integrated fuel cycle with exceptional sustainability and safety characteristics. With respect to fuel utilization, there is practically no fuel burn-up limit for gas core reactors due to continuous recycling of the fuel. Owing to flexibility in nuclear design characteristics of cavity reactors, a wide range of conversion ratio from almost solely a burner to a breeder is achievable. The continuous recycling of fuel in G/VCR systems allows for continuous burning and transmutation of actinides without removing and reprocessing of the fuel. The only waste product at the backend of the gas core reactors' fuel cycle is fission fragments that are continuously separated from the fuel. As a result the G/VCR systems do not require spent fuel storage or reprocessing.

G/VCR systems also feature outstanding proliferation resistance characteristics and minimum vulnerability to external threats. Even for comparable spectral characteristic, gas core reactors produce fissile plutonium two orders of magnitude less than Light Water Reactors (LWRs). In addition, the continuous transmutation and burning of actinides further reduces the quality of the fissile plutonium inventory. The low fuel inventory (about two orders of magnitude lower than LWRs for the same power generation level) combined with continuous burning of actinides, significantly reduces the need for emergency planning and the vulnerability to external threats. Low fuel inventory, low fuel heat content, and online separation of fission fragments are among the key constituent safety features of G/VCR systems.     

The raw material and waste activity balance in the projected nuclear power of Russia

Under discussion is the management of long-lived high-level wastes in the nuclear energy sector of Russia, the development of which on a large scale in the next century is motivated by the need for arresting the increasing consumption of fossil fuels. The prerequisites for the nuclear power growth consists in the design of naturally safe reactors and development of a transmutational nuclear fuel cycle (NFC) technology. The choice of operations in such a cycle and of their quantitative characteristics, is aimed at minimizing the wastes to approach the radiation balance with the natural uranium extracted and put to use. The paper discusses the way the approximation to the balance between the raw material and waste activity is influenced by introduction of the transmutational NFC (in case 2), inclusion of transmutation reactors into the energy mix (case 1), partial disposal of actinide wastes into outer space, and by recycling of protactinium (case 3). It is shown that such a balance can be sustained for a considerable time in cases 2 and 3 or throughout the operation stage of the future nuclear power (case 1).