Lead fast reactor

Development of the SSTAR has been supported under the lead fast reactor element of the U.S. DOE Generation IV Nuclear Energy Systems Initiative. Development of the SSTAR small modular fast reactor under Generation IV involves liquid metal fast reactor related... 

Lead Fast Reactor Design and Safety, Nuclear Engineering Division, Argonne National Laboratory (ANL),... 

ALFRED Advanced Lead Fast Reactor European Demonstrator... 

Frogheri, M., Alemherti, A., Mansani, L., March 4—7, 2013. The lead fast reactor demonstrator (ALFRED) and ELFR design. In IAEA—International Conference on Fast Reactors and Related Fuel Cycles Safe Technologies and Sustainable Scenarios (FR13), Paris, France. 

ALFRED (Advanced Lead Fast Reactor European Demonstrator) demonstrator with lead coolant, to be hosted in Romania. The Fostering ALFRED Construction consortium is composed of Romania s Nuclear Research Institute (RATEN-ICN). The project is led by Ansaldo Nucleare and Italy s National Agency ENEA. 

ALFRED Advanced lead fast reactor European demonstrator... 

All six Generation-IV reactor types are targeted in this training scheme the lead fast reactor (LFR), sodium fast reactor (SFR), gas fast reactor (GFR), very high temperature reactor (VHTR), super critical water reactor (SCWR), and molten salt reactor (MSR). 

A4.1.2 Design specific knowiedge for the lead fast reactor... 

Uranium and mixed uranium—plutonium nitrides have a potential use as nuclear fuels for lead cooled fast reactors (136—139). Reactors of this type have been proposed for use ia deep-sea research vehicles (136). However, similar to the oxides, ia order for these materials to be useful as fuels, the nitrides must have an appropriate size and shape, ie, spheres. Microspheres of uranium nitrides have been fabricated by internal gelation and carbothermic reduction (140,141). Another use for uranium nitrides is as a catalyst for the cracking of NH at 550°C, which results ia high yields of H2 (142). 

Further away in time are possibilities of using fast reactors, though, at least for some decades, not as breeders. The Soviet navy has been using such reactors, using a lead/bismuth eutectic mixture as coolant, for some decades in some of their high performance submarines and it is understood that work is now going on to see whether this design could be made suitable for small commercial power production... 

Nuclear and magneto-hydrodynamic electric power generation systems have been produced on a scale which could lead to industrial production, but to-date technical problems, mainly connected with corrosion of the containing materials, has hampered full-scale development. In the case of nuclear power, the proposed fast reactor, which uses fast neutron fission in a small nuclear fuel element, by comparison with fuel rods in thermal neutron reactors, requires a more rapid heat removal than is possible by water cooling, and a liquid sodium-potassium alloy has been used in the development of a near-industrial generator. The fuel container is a vanadium sheath with a niobium outer cladding, since this has a low fast neutron capture cross-section and a low rate of corrosion by the liquid metal coolant. The liquid metal coolant is transported from the fuel to the turbine generating the electric power in stainless steel... 

Actinide nitrides are known for Th through Cm. All of the nitrides are high melting compounds with melting points of 2630 °C, 2560 °C, and 2580 °C for Th, Np, and Pu, respectively. The actinide nitrides can decompose to give N2. Thorium, uranimn, and plutonium nitrides are well known and can be used as nuclear fiiels. Fuels of this type, especially uranium and mixed uranium plutonium nitrides, can be used in lead-cooled fast reactors, which have been proposed as a possible next-generation nuclear reactor and for use in deep-sea research vehicles. 

Abel et eil. [57,58] studied the effect of reactor and gamma-ray irradiation on the impact sensitivity of colloidal lead azide. Reactor irradiations ranged from 3.3 X lO to 1.57 X lO nvt (n/cm ) (fast plus slow neutrons) with an accompanying reactor gamma dose rate of 2 X 10 R/hr. The results (Figure 11) indicated an increase in the impact sensitivity of colloidal lead azide as a function of neutron dose. The studies also revealed an incompatibility of colloidal lead azide with Teflon and aluminum during long-term reactor exposures. 

Shirin, V. M., et al. Use of Lead in Unloading Systems of Sodium-Cooled Facilities, in IAEA Symposium on Progress in Sodium-Cooled Fast Reactor Engineering, Monaco, Mar. 1970. 

It is obvious that the neutron energy spectrum of a reactor plays an essential role. Figure 19.4 shows the prompt (unmoderated) fission neutron spectrum with 2 MeV. In a nuclear explosive device almost all fission is caused by fast neutrons. Nuclear reactors can be designed so that fission mainly occurs with fast neutrons or with slow neutrons (by moderating the neutrons to thermal energies before they encounter fuel). This leads to two different reactor concepts - the fast reactor and the thermal reactor. The approximate neutron spectra for both reactor types are shown in Figure 19.4. Because thermal reactors are more important at present, we discuss this type of reactors first. 

At the present state of the art, a corner of an article about evaluation of population hazards is hardly an appropriate place in which to attempt an exposition of reactor safety. Nevertheless, we may contrive a brief description of these types of reactor accidents which, it is thought, could lead to fission product release. The intention is to illustrate ways in which fuel could be damaged and then release fission products ultimately to the atmosphere. Though gas-cooled reactors, water-cooled reactors, and sodium-cooled fast reactors will be discussed, no comparisons, invidious or otherwise, are intended between the safety of these systems. 

In the earlier phases of breeder reactor development, especially in the 1950s and 1960s, high pressure gases, such as helium,C02 or superheated steam were studied. Between 1960 and 1970, H2 0-steam cooled and D2 0-steam cooled fast reactor concepts were studied in the USA and the former FRG. Helium cooled fast reactor concepts have been pursued as an alternative coolant concept in Europe and the USA. Some fuel development for a CO2 cooled fast breeder has been continued on a small scale in the UK. Lead-bismuth alloy as a coolant was studied in the former USSR for propulsion and land based reactors. 

Not only new innovative ideas as, for example, lead or lead-bismuth cooled fast reactors are being studied in Member States now, but almost all old ones mentioned above... 

Considerable experience has been gained in the Russian Federation with lead-bismuth (PbBi) eutectic alloy application as reactor coolant. Since Bi is sufficiently rare and expensive metal, and also it is a source of volatile a-active Vo, the proposal to use lead as a coolant in power fast reactors is now under consideration in several countries. Lead based alloys are currently being considered for hybrid systems (accelerator driven fast reactors) in which the coolant could double as the spallation source for driving the core. 

Techniques to counter the heavy metal coolant disadvantages are being developed, but in spite of this work and the apparent disadvantages of sodium, the consensus in favour of sodium remains strong. This is demonstrated by fact that before lead-cooled fast reactor BREST-300 is built, MINATOM will first build a sodium-cooled LMFR BN-800 (E. Adamov, NW, 23 September 1999). Moreover, in the last few years sodium has been chosen in both China and the Republic of Korea for the respective fast reactor development project. This is a significant endorsement for sodium as a fast reactor coolant. 

That is why this report is devoted to the comparative assessment of general characteristics of a standard fast reactor coolant (sodium) and innovative ones, such as lead and lead-bismuth alloy. 

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