Nuclear fast reactor liquid metal cooled
(57) Abstract:Usage: the invention relates to the field of nuclear technology and can be applied mainly for energy or research facilities using nuclear fast reactor. Essence: active area and side screen fast reactor liquid metal cooled, made the type of reactor in the form of a set of fuel reproducing and irradiation channels, located in the nodes of a regular or irregular lattice and separated that weakly absorb and subsumesa neutrons environment, for example, with an inert gas. Step placement of the channels is selected to provide close to zero (less than the effective delayed neutron fraction) or negative void coefficient of reactivity. As a result, significantly improves the security of fast reactor due to the guaranteed supply of negative values void reactivity effect, and improve reliability and performance system CPS. 3 Il., table 1. The invention relates to the field of nuclear technology and can be applied mainly for energy or issledovatelskiy case of fast reactors with liquid metal coolant. The use of liquid metal, usually sodium, helps to provide a high energyproject fuel, high reproduction rate, increased the efficiency of thermodynamic cycle and does not require high pressure, which increases the safety of the reactor. The specific problem of rapid large reactors, primarily sodium cooled is large (in the above bn-800 5-6 EF) positive sodium void reactivity effect (NPAR), which negatively affects its safety in emergency situations with the devastation of the active zone or the boiling of sodium. The main reason for the positive NPAR is a small leakage of neutrons from the core due to the large size of the last reactor of high power (600 MW and above). The problem of positive NPAR compounded if the fast reactor is used for burning minor actinides (MA) isotopes of neptunium, americium, curium. It is shown that the increase in the content of MA in the active zone of 2% leads to an increase in the positive sodium reactivity at 20% Obvious and used in practice by solving the positivity NPAR is an increase in the leakage of neutrons from active), refusal end screens, placing special sodium cavity over the active area or inside the organization of gas volumes in the active zone (a project of the advanced liquid metal reactor ALMR based on the concept of PRISM).In the invention (patent SU 1799178 A1, class G 21 C 1/02) the design of fast reactor liquid metal cooled with a porous active area. In this application to "deficiencies in the prototype (the bn-800 approx. ed.) with a dense arrangement of fuel assemblies containing the beam sterzenbach fuel rods to the coolant flow, the active area is made of materials, including fuel, having a small average cell density, i.e., increased effective porosity, and the porosity achieved by education in the core is empty (gazonapolnennyh) volumes in one of the following options nutritiona porosity or nutritiona in combination with midvalley or marcassite, and the porosity calculated in advance depending on the reactor power". Thus, for the implementation of the proposed patent N 1799178 design requires the creation of a special porous TVEL, which when compared with traditional fuel rod dimensions, will have a material is a, as a Cabinet-type fast reactor bn-800 with integrated layout that will lead to a significant increase in the size of the reactor vessel. The increase in the size of housing is particularly undesirable in the case of a heavy fluid, because it increases the seismic hazard for the reactor. The proposed method of introducing midvalley and marcassite porosity type reactor bn will lead to increased sodium and steel in the composition of the active zone and, consequently, to mitigate the spectrum and reduce the replacement rate. So in the variant with a porous active zone of reactor bn-800  the volume of the active zone increased to 15600 l compared to 4840 l in bn-800 with a traditional layout, i.e., 3.2 times. Accordingly, and housing dimensions dimensions-reactor storage and storage for long-term spent fuel assemblies. Reproduction rate of the porous active zone (KVA) fell to 0.31, i.e., was one and a half times less than even the VVER.As a prototype of the present invention describes the design of a nuclear reactor-fast breeder reactor bn-800 liquid metal (sodium) cooled. The reactor consists of an active area, the content is the totype are:
1. The presence of a positive sodium void effect at full load MOX fuel and in the presence of reproducing side and end screens.2. Communication agencies cor circulation of the coolant, thus reducing the potential danger of the release of the bodies of CPS from the active zone.3. A large amount of liquid metal coolant, concentrated in a single volume of the reactor vessel, creating increased seismic hazard and high hazard damaged casing.The main technical problem to be solved in this invention is the elimination of the above disadvantages when:
any question at present and for the foreseeable future reactor power (up to 2000 MW El.) and for any physically justifiable share of MA in the fuel;
traditional for fast reactors worked well sterzenbach rods with large effective density of the fuel composition is adopted in the present loading of heavy atoms per unit length of fuel rod;
To solve the above problem is proposed fast reactor liquid metal cooled channel type. The layout of active areas, each individually to the BMC, CANDU, PGE-6, etc. For fast reactors with liquid metal cooling scheme of the reactor is still not used. Meanwhile, for this type of reactor channel layout seems to be the most simple and attractive compared to the channel layout of a thermal reactor.First, the channel in thermal reactors, the space between the channels is filled with a moderator usually graphite or heavy water. For fast reactor this is not required, here the space between the fuel channels should be filled with that weakly absorb neutrons environment, for example, with an inert gas under low pressure, which greatly facilitates the design of the active zone, alleviates problems associated with overheating, burning, swelling, deformation of graphite or the production of tritium in the heavy water moderator.Secondly, high energyproject fuel provided through the use of liquid metal coolant, allows for the same with thermal reactor power to decrease the number and height of the channels. Estimates show that when the power of the fast reactor of 1000 MW (e) will be enough to 160 channels with height actively the height of the active zone 700 see This allows to simplify the system inlet and outlet pipes.Thirdly, the liquid metal coolant does not require high pressure, there is no boiling of the coolant, which allows for the manufacture of covers, fuel channels, inlet and outlet piping to use thin-walled tube, thus minimizing the parasitic capture of neutrons in the core and overall metal structure. Greatly simplified, and the problem of sealing the case.In General, the design of the active channel zone, the system inlet and outlet pipes for fast reactor liquid metal cooled it seems much simpler (less bulky, less bulky) than the design of the operating channel reactors on thermal neutrons. Design and manufacturing technology of the latter are well tried and tested by many years of practice. This experience can be used to create channel of the reactor on fast neutrons.The main advantages of fast reactors channel-type front hull (and the latter applies to the prototype fast reactor bn-800) are sleeky, energonapryazhennosti fuel becomes possible to optimize the leakage of neutrons from the active zone by choosing the size of the fuel channels and channels playback screen, and most importantly, through their step placement, achieving desired by the magnitude of the void coefficient of reactivity.The physical reason for this phenomenon is the increase in the leakage of neutrons from the active zone with the vacuum lattice channels, i.e., the same as when using other known methods of reducing NPAR described above (flattening of the zone, refusal end of the screens, the introduction of sodium and gas cavities in the active zone, nutritiona porosity, supplemented by midvalley and marcassite porosity).2. Channel layout is the possibility of individual adjustment of the coolant flow in the fuel channels, providing the optimum temperature for the fuel rods.3. The space between the channels can be used for hosting CPS agencies and irradiation devices. Significant positive aspect is the independence of the organs of CPS from the first cooling circuit of the reactor, the control rods may not be actively ejected from the space can be used for ultrafast quenching of the reaction by introducing under pressure He-3.4. The absence of a completed cooled reactor gives an important advantage of the channel reactor from the point of view of seismic stability especially when using lead-bismuth coolant. In case of damage to the reactor consequences from the devastation of the active zone or from the combustion of sodium will be much more severe than the damage to a single channel. Resource casing is limited by its radiation and thermal resistance. Replacement case energy installation is almost impossible, while the covers of channels can regularly as necessary, be replaced by a new and thus the lifetime of the reactor can be greatly increased.5. There is a principal possibility (at least for the side of the screen) overload the reactor at power, thereby increasing its economic indicators.6. Channel arrangement facilitates removal of residual heat in the event of termination of the circulation of the coolant in the first circuit, and also greatly simplifies the solution of the dispersion of the corium in the case of meltdown to prevent the formation of secondary Christmassy.NH channels, sector 60 deg. where: 1 - the fuel channel 2 playback channel 3 irradiation channel, 4 - pin SMT, 5 biological protection; Fig.2 is an example of arranging the active zone channel fast reactor with a square lattice of the fuel channels, sector 90 deg. where: 1 fuel channel 2 playback channel, 3 - irradiation channel 4 pin SMT, 5 biological protection; Fig.3 - the dependence of the sodium void reactivity effect and critical plutonium content in MOX fuel from the spacing of the channels in the channel fast reactor with a triangular lattice of channels, with a capacity of 1000 MWe sodium cooled, where: 1 the dependence of the sodium void reactivity effect of the step location of the fuel channels, 2 the dependence of the critical plutonium content in MOX fuel from the spacing of the fuel channels.Example link channel fast reactor with a triangular lattice placement of the fuel, reproducing and irradiation channels (not necessarily of equal diameter) and bodies CPS placed in the channel space, shown in Fig.1. A similar example for the channel reactor with a square lattice occupancy of the channels shown in Fig.2.Topl is or natural uranium, thorium) is placed in the reproducing channels 2. Irradiation channels 3 are used for producing isotopes, burn actinides or long-lived fragments, irradiation of various materials. The cooling channels is performed by using liquid metal coolant supplied individually to each channel and pumped through them in the required quantity and at the required rate. The space between the channels are filled with an inert gas such as argon. Control of the chain reaction is carried out by using control rods placed in the space between the channels and independent of the first path. As a fast-acting emergency protection can be used for rapid filling of interchannel space absorbing gas such as He-3. The reactor is sealed in a concrete pit, lined with steel.Thanks razrezhennogo placement of the fuel channels is increased leakage of neutrons from the core, thus providing a negative value sodium void reactivity effect.Conducted computational studies of neutron-physical characteristics of variant channel fast), confirmed the possibility of achieving negative values of sodium void reactivity effect an appropriate step placement channels.In Fig.3 shows the calculated dependence of NPAR from step placement of the channels for one of the alternative channel fast reactor with capacity of 1000 MW (e). The main parameters of the reactor are given in table.The figure shows that with increasing step of placing channels the value of NPAR drops to zero and then becomes negative. Thus, for the above-described channel fast reactor when the spacing of the channels in a triangular lattice 48 cm, provided required by the rules of nuclear safety negative value sodium void reactivity effect.It is important to note that this is an important security property is achieved using waste and spent long practice in existing fast reactors the size and design of fuel elements, at a moderate to fast reactors energonapryazhennosti fuel. Nuclear fast reactor liquid metal cooled containing the active zone, side and end view for fuel, reproducing and irradiation assemblies placed in the nodes of a regular or irregular lattice and separated by a gas environment or vacuum.
FIELD: nuclear power engineering.
SUBSTANCE: proposed containment has inner space accommodating condensing chamber, high-pressure chamber, cooling pond, and discharge pipe. It is also provided with condenser communicating with high-pressure chamber. Discharge pipe is component part of inner space that provides communication between high-pressure chamber and condensing chamber. Condenser may be mounted in high-pressure chamber with top end of discharge pipe disposed above condenser. Operating process of condenser in nuclear power plant is characterized in that nondensables are automatically discharged from above-condenser area.
EFFECT: enhanced safety in operating nuclear power plants.
13 cl, 1 dwg
FIELD: nuclear power engineering; nuclear plants for transmutation of radioactive wastes including excess nuclear weapon materials.
SUBSTANCE: proposed method that provides for commencing and ceasing nuclear reaction simply by starting and stopping fuel pumps, effective monitoring and control of nuclear reaction, neutron energy spectrum, and transmutation speed includes production of nuclear-reactor liquid-fuel core by stream of liquid fuel jets formed by means of holes in delivery chamber at core inlet and its discharge to vacant state at core outlet. Core jets are cooled down by means of helium circulating within reactor vessel. Liquid fuel is supplied from liquid state to delivery chamber by means of pumps thereby initiating chain fusion reaction within reactor core. Remaining spaces of liquid fuel loop are always maintained in subcritical state. Stopping liquid fuel pumps causes core disappearance.
EFFECT: facilitated procedure, reduced cost and enhanced safety of radioactive waste transmutation process.
FIELD: nuclear power engineering.
SUBSTANCE: proposed core used for water-moderated water-cooled reactors, and type VVER-1000 in particular, is characterized in that water-uranium ratio of fuel lattice, outer and inner diameters of fuel element cladding are 1.51 to 2.10, 7.00 · 10-3 to 7.50 · 10-3 m, and 5.93 · 10-3 to 6.36 · 10-3 m, respectively, for fuel assemblies incorporating 468 to 510 fuel elements, or water-uranium ratio for fuel lattice, outer and inner diameters of fuel element cladding are 1.49 to 2.06, 7.60 · 10-3 to 8.30 · 10-3 m, and 6.45 · 10-3 to 7.04 · 10-3 m, respectively, for fuel assembly having 390 to 432 fuel elements, or water-uranium ratio of fuel lattice, outer and inner diameters of fuel element cladding are 1.61 to 2.03, 8.30 ·10-3 to 8.89 · 10-3 m, and 7.04 · 10-3 to 7.46 · 10-3 m, respectively, for fuel assembly with 318 to 360 fuel elements, core height to fuel assembly length ratio being 0.7677 to 0.7945.
EFFECT: reduced linear heat loads and fuel element depressurization probability, enlarged reactor power control range, enhanced fuel utilization.
5 cl, 16 dwg
FIELD: research thermal pulse reactors.
SUBSTANCE: proposed nuclear reactor has cylindrical tank of diameter D filled with water moderator and accommodating reactivity modulator incorporating N dry tubes axially and symmetrically disposed over diameter D1 on tank bottom. Dry tubes accommodate movable tubes filled with water, each tube holding two rods made of neutron absorbing material. Rods are rigidly fixed on common hollow shaft at distance R from movable tube axis and at distance 2R from each other. Values of 2R and D1 are found from following expressions: 0.107D > 2R > 0.105D; 0.806D > D1 > 0.8D; protective elements have storage capacitor with spark gaps.
EFFECT: enlarged functional capabilities due to evacuating central test channel in core, reduced neutron background level, enhanced nuclear safety of plant.
2 cl, 5 dwg
FIELD: the invention refers to nuclear technique particularly to construction of homogenous fast reactor on suspension.
SUBSTANCE: the homogeneous fast reactor-reservoir is characterized thereby that thermal contour working on natural circular fine-dispersed dredge of the fuel particles in liquid metal carrier contains an active zone of variable volume, has under critical stagnant zones with an open surface also having a reserve volume. Together with refrigerating part of the liquid metallic refrigerating contour it is contained inside closed volume limited by an external body of the reactor. Liquid lead and its alloys are used as carrier of fuel particles in a fuel contour and thermal carrier in the refrigerating contour and mixture of raw and fissionable species serves as a fuel for starting feeding. The rising section of the fuel contour is fulfilled in the form of a vertical cylindrical housing with inputs from below and outputs from above, lateral openings connecting the housing relatively with assembled and distributed collectors of ramified system of thermal tubes, paved together with the tubes if the refrigerating contour in space between the external wall of the housing and the inner wall of the reactor's body. An ousting plug is immersed in the upper part of the housing with a gap for passing of suspension. The plug is fulfilled with possibility of vertical displacement relatively to the wall of the housing, and the vacant lower part of the housing serves as active zone the volume of which is determined by the position of the plug. The external body of the reactor is fulfilled in the form of high-fusing bucket closed with a protective cover with openings for loading and other technological channels which are designed for keeping non-volatile radioactivity at temperatures no higher than the point of boiling of the lead and located inside the protective structure fulfilled of heat resistant cement-basalt or similar other mineral foundation.
EFFECT: allows to insulate the fuel contour inside closed volume.
4 cl,3 dwg
FIELD: nuclear physics; multiplying neutrons for building subcritical nuclear reactors.
SUBSTANCE: proposed multistage neutron multiplier has a number of multiplication stages abutting against each other. Each stage has coaxially arranged disks of different thickness abutting against each other. Disks are assembled of active material, neutron moderators of two types, and neutron absorber. They are alternating in stage so as to ensure unidirectional movement of neutrons and their multiplication.
EFFECT: enhanced neutron multiplication factor.
2 cl, 2 dwg
FIELD: radiation engineering.
SUBSTANCE: proposed gamma-ray installation used in particular to irradiate modular objects to sterilize, pasteurize, or modify them has irradiation chamber accommodating isotope radiation sources placed in irradiator, system for displacing irradiator and object being irradiated made in the form of pushing conveyer, control and radiation protective system. Isotope sources are placed in irradiation chamber into two parallel flat irradiators mounted for free sequential passage of target object modules on all sides of irradiator so as to ensure their two-way irradiation.
EFFECT: enhanced radiation safety and irradiation efficiency.
FIELD: fuel cells designed for use in gas-cooled nuclear reactor core.
SUBSTANCE: fuel cell 10 designed for use in gas-cooled nuclear reactor has assembly of two adjacent fuel plates 12a, 12b disposed relative to one another and shaped so that they form channels 14 for gaseous coolant flow. Fuel plates 12a, 12b incorporate elementary fissionable particles, better non-coated ones, implanted in metal matrix. Metal coating may be deposited on both ends of each plate 12a and 12b.
EFFECT: enlarged heat-transfer surface, enhanced power density per volume unit.
13 cl, 5 dwg, 1 tbl
FIELD: nuclear technology; atomic power stations with water-cooled nuclear reactors.
SUBSTANCE: the invention is pertaining to the field of nuclear technology, in particular, to atomic power stations with water-cooled nuclear reactors. The nuclear reactor contains: the body and the cover with the branch-pipes for outputs of the detectors of the intrareactor control; the pins with the screw nuts for tightening of the above-mentioned cover to the body. On the branch-pipes for outputs of the detectors of the intrareactor control there are safety devices fixed on the pins for tightening of the cover to the body by additional screw nuts. The invention allows to increase safety of the nuclear reactor operation.
EFFECT: the invention allows to increase safety of the nuclear reactor operation.
FIELD: nuclear industry and other industries using parts suffering in operation impact of liquid-metal temperature and corrosion.
SUBSTANCE: in manufacturing fuel element with heat-transfer liquid-metal layer use is made of not pure lead but its alloy incorporating chemical elements of fuel element cladding in amount affording chemical equilibrium of fuel element cladding with contacting heat-transfer lead layer under temperature and other operating conditions. Using low-alloyed lead instead of high-cost pure lead enhances corrosion resistance of fuel element cladding.
EFFECT: enhanced service life and reduced production cost of fuel elements.