RU2463496C1 - Controlled elastoplastic damper for equipment and pipelines of nuclear power station reactor primary circulation circuit - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: damper comprises hollow twin torsion made from alloy with memory effect. Said torsion is coupled with equipment and pipelines attachment bracket lever. Nuclear power station reactor floor bed accommodates vibration transducer connected with control unit and power supply. Smaller feed pipelines are connected with torsion and filled with heat carrier and communicated with heat and cold heat carrier bypass valves. Bypass valves are communicated via cable lines with control unit. Hot heat carrier bypass valve of the main circulation circuit is communicated via small feed pipeline with nuclear power station reactor outlet circuit. Cold heat carrier bypass valve is communicated with main circulation pump outlet circuit. Temperature transducer thermocouple is secured on torsion, connected with control unit by cable line.

EFFECT: high thermal capacity, efficient damping, reusability.

2 dwg

Description

The invention relates to special mechanical engineering, in particular to seismic isolation systems, and may find application in the creation of controlled elastic-plastic dampers of functional elements of nuclear power plant reactors.

A natural tendency around the world — the tightening of regulatory requirements for the safety of nuclear power plants and guarantees for its provision, as well as the periodic review of seismic ballasting at sites of existing nuclear power plants in the direction of increasing it — makes it necessary even for equipment designed and manufactured in earthquake-resistant design to conduct periodic checks and develop additional antiseismic measures during the operation of nuclear power plants. This problem is especially relevant for nuclear power plants with a long service life (20 years or more) designed either without the requirements of earthquake resistance, or according to outdated regulatory requirements and initial seismic data.

Also known are seismic isolation systems made in the form of swinging posts, supplemented with dampers, in which the protective shell rests on supports made with the possibility of their movement along the foundation plate in the radial direction.

Known depreciation systems, elastoplastic dampers containing torsions, during torsion of which the impact energy is absorbed, which is usually of an oscillatory nature [1, 2].

Known controlled elastoplastic torsion dampers in which the elastic properties of working elements based on an alloy with a shape memory effect change when heated by direct current [3, 6].

The prototype of the proposed design is a controlled depreciation system in which the elastic properties of the working element, a hollow torsion made of an alloy with a shape memory effect, change when a coolant is passed through it. The coolant used is a coolant [4].

The disadvantages of the prototype, as applied to the controlled elastoplastic damper of the pipelines of the NPP reactor, are the low efficiency of using special coolant as a coolant, which can involve significant space of the NPP premises and worsen the functional perfection of the entire system [7, 8].

When designing seismic isolation systems, there is a need with minimal energy consumption with a fairly simple design to increase the efficiency and reliability of vibration damping of elements of nuclear power plants.

This problem can be solved as follows (see Fig. 1, 2): a controlled elastoplastic damper of the equipment and pipelines of the main circulation loop of the NPP reactor, shown schematically in Figures 1 and 2, contains a double hollow torsion 1 made in whole or in part from a thermoelastic damping alloy with shape memory effect. The middle part of torsion 1 is connected to the lever 2 of the bracket for fastening equipment and pipelines 3 of the main circulation loop of the NPP reactor - the damping object. The ends of the torsion bar 1 are covered by earrings 4, allowing it to curl when the lever 2 is moved, and rigidly fixed to the supporting platform 5 of the nuclear power plant reactor. On the supporting platform 5 there is a vibration sensor 6 connected to the control unit 7 and the power source 8. A torsion 1 is connected on one side to a small supply pipe 9 filled with a coolant and connected to a bypass valve of the hot coolant 10 and with a bypass valve of the coolant 11, s on the other hand, a small outlet pipe 12 leading to the inlet of the main circulation pump 18. Bypass valves 10 and 11 are connected by cable lines 13 to the control unit 7. The bypass valve of the hot coolant 10 heads th circulation circuit is connected via the feed pipe with small output path 15 of the reactor plant. The bypass valve of the cold coolant 11 of the main circulation circuit is connected via a small pipe 16 to the output path 17 of the main circulation pump 18. The coolant of the main circulation circuit comes from the heat exchanger 19 to the main circulation pump 18 and is the cooler of the reactor 15 of the nuclear power plant. A thermocouple 20 of the temperature sensor 21 is fixed to the torsion 1, connected by a cable line 13 to the control unit 7.

The operation of this controlled elastoplastic damper occurs as follows: in the absence of coolant movement inside the hollow torsion 1, the torsion has a stable temperature corresponding to the temperature of the NPP compartments and is deformed by torsion, with the energy dissipating the damping object 3 in the elastic or elastoplastic region. Moreover, the properties of the material are practically unchanged, and plastic deformations are not restored [6].

In the control mode of vibration damping, under the action of a seismic alternating load from the external influence on the damping object 3, the vibration level is determined by the sensor 6. Depending on the vibration level, the control unit 7 issues commands to supply the coolant either from the hot coolant bypass valve 10 or from the bypass valve coolant 11 through the small supply pipe 9 into the cavity of the torsion 1. When changing the temperature of the torsion 1, made of thermoelastic damping with melt with the shape memory effect, for example, based on the Ni-Ti system, from 20 ° C to 295 ° C the yield strength varies significantly (up to 90 ... 115% [6]). By changing the mechanical properties of the alloy depending on temperature, the shape of the elastoplastic hysteresis during torsion 1 torsion is significantly affected and the operating frequency range of the controlled elastoplastic damper of the damping object 3 is expanded. Moreover, in accordance with the influence of a certain law, changes in the temperature of torsion 1 taking into account inertia to achieve a minimum level of vibration of equipment and pipelines - damping object 3.

When a damping object 3 is exposed to a significant shock load, for example, in the event of an earthquake, plastic torsion 1 torsion occurs, which occurs with absorption and dissipation of shock energy, a signal proportional to the shock value is transmitted from the vibration sensor 6 to the control unit 7. At the command of the control unit 7, the bypass valve of the hot coolant 10 opens, heated in the cooling path 14 of the reactor 15 of the nuclear power plant to a temperature of 260 ... 290 ° C [7, 8] under high pressure, the coolant flows through the inlet pipe 9 to torsion 1.

The heating of torsion 1 is carried out to a temperature at which the shape of the twisted torsion is restored. In this case, the temperature of the coolant is controlled by means of a thermocouple 20 mounted on the torsion bar 1 and a temperature sensor 21 connected by a cable line 13 to the control unit 7. The signal from the temperature sensor 21 through the cable line 13 to the control units 7 about heating the torsion 1 to a temperature above, for example, 260 ° C, closes the bypass valve of the hot coolant 10 and opens the bypass valve of the cold coolant 11. The desired temperature is maintained.

The return of the lever 2 of the controlled elastoplastic damper is ensured by the force of thermoelasticity of the alloy of which the torsion 1 is made, at the temperature of restoration of the form.

After restoration of the form, torsion 1 is cooled to operating temperature by the heat carrier, which comes only from the bypass valve of the coolant 11 through the supply pipe 9 into the cavity of torsion 1.

A controlled elastoplastic damper with restored torsion 1 can work under repeated exposure conditions, that is, damp vibrations of a wide frequency range with a stroke of lever 2, in which deformations in the material of torsion 1 do not exceed elastic, and also protect equipment and pipelines from repeated powerful seismic shocks with the maximum possible stroke of the lever, at which plastic deformation of the torsion material occurs, after which the restoration of the torsion shape follows again.

During operation of the controlled elastoplastic damper, the control unit 7 can receive commands directly from the central control system, and in the case of manual control, from the operator, which can improve the efficiency of work.

The controlled elastoplastic damper allows you to significantly restore the initial position of the displaced equipment and pipelines after seismic shocks, which reduces the duration of loads on structural materials and, therefore, the likelihood of a negative accident.

At the same time, the controlled elastoplastic damper has high resistance to radiation exposure, aggressive environments, explosion and fire safety, non-toxic materials used, low reaction force, the absence of delayed response under dynamic load, the ability to control and adjust the stiffness and dissipation characteristics during operation.

The positive effect is due to the use of a double hollow torsion as a working element of a controlled elastoplastic damper made of a thermoelastic damping alloy with a shape memory effect that is resistant to aggressive environments, equipped with bypass valves, and the use of a coolant coming from the main circulation loop of the NPP reactor as a heat carrier also complemented by a thermocouple and a temperature sensor connected to the control unit.

The proposed controlled elastoplastic damper has, in comparison with the prototype, a design of increased efficiency due to the use of thermal energy of the NPP reactor, providing more effective protection of equipment and pipelines from vibration, and improving the reliability and speed of reusable applications under seismic shock loads of a calculated nature due to the use of control sensors in the design torsion temperature.

Thus, the proposed damper has a much more reliable design, which has a high energy intensity, provides more effective damping of oscillations in a wide range of operating frequencies and has an increased speed of reusable use during repeated shock loads.

INFORMATION SOURCES

1. USSR author's certificate No. 1196560, cl. F16F 11/00, 1985.

2. USSR author's certificate No. 1562558, cl. F16F 6/00, 1990.

3. RF patent No. 2073142, cl. F16F 1/14, 1997.

4. RF patent №2256831, cl. F16F 1/14, B60G 11/18, 2005.

5. RF patent No. 2031456, cl. G21C 13/00, 1995.

6. The effect of shape memory in alloys: Trans. from English L.M.Bernshtein / Ed. V.A. Zaimovsky - M .: Metallurgy, 1979.- 472 p.

7. I.Kh. Ganev. Physics and reactor design. Textbook for high schools - M .: Energoatomizdat, 1992.

8. L.V. Matveev, A.P. Rudik. Almost everything about a nuclear reactor. - M., 1990.

Claims (1)

Controlled elastic-plastic damper of equipment and pipelines of the main circulation loop of the reactor of a nuclear power plant (NPP), containing a double hollow cylindrical torsion, made in whole or in part from a thermoelastic damping alloy with a shape memory effect, the middle part of which is connected to the arm bracket of the equipment and pipelines of the main circulation loop of the reactor NPP - damping object, the ends of the torsion are covered with earrings, allowing it to curl when the lever is moved , and are rigidly fixed on the supporting platform of the NPP reactor, on which the vibration sensor is connected, connected with the control unit and the power source, the main circulation circuit, consisting of a heat exchanger, the main circulation pump and the cooling path of the reactor, characterized in that with torsion bar on one side connected inlet small pipe filled with coolant and connected to the bypass valve of the hot coolant and the bypass valve of the coolant, on the other hand, the output small pipes the wire leading to the inlet of the main circulation pump, the bypass valves are connected by cable lines to the control unit, the bypass valve of the hot coolant of the main circulation loop is connected via the small supply pipe to the output path of the reactor, the bypass valve of the cold coolant of the main circulation loop is connected by the small pipe the main circulation pump, the coolant of the main circulation circuit comes from the heat exchanger to the main circulation pump and is the cooler of the reactor of the nuclear power plant, a thermocouple of the temperature sensor is connected to the torsion bar, connected by a cable line to the control unit.

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