EP3992369A1

EP3992369A1 - System for damping mechanical oscillations transmitted from the structural part of built structures to the electrical equipment and/or software and hardware systems of nuclear power stations

Info

Publication number: EP3992369A1
Application number: EP20832901.1A
Authority: EP
Inventors: Aleksey Yuryevich TENIAKOV; Evgeny Alekseevich TENIAKOV
Original assignee: Eat Joint Stock Co
Current assignee: Tenza Tenza Ood LLC
Priority date: 2019-06-28
Filing date: 2020-02-12
Publication date: 2022-05-04
Anticipated expiration: 2040-02-12
Also published as: EP3992369B1; WO2020263123A1; EP3992369A4; RU2709273C1

Abstract

The invention relates to means for protection of packaged electronic and electrical equipment, as well as automated control system software and hardware systems (ACS SHS), mostly for NPP, from earthquakes and man-made impacts that lead to mechanical oscillations of foundations of structures, as well as to means of protection against the effects of industrial vibration, which leads to mechanical aging of elements of devices making part of ACS SHS and electrical equipment. The system for damping mechanical oscillations transmitted from the structural part of built structures to packaged electrical equipment and/or software and hardware systems of the NPP automated control system comprises a base on which electrical equipment and/or software and hardware system of the NPP automated control system are installed and/or placed, where the base is a bearing and/or supporting unit, which includes 3D-compensators. The system additionally comprises at least one load-bearing girder, at least one low-frequency oscillation damping unit mounted between the foundation of the structure for installing the base of the structure and the load-bearing girder(-s) on which the 3D-compensators are mounted. The low-frequency oscillation damping unit has a vertical oscillation damper pre-compressed by a predetermined amount, blocked with a lock of the vertical damping activator, and a horizontal oscillation damper in the form of a movable support mounted on a supporting plate through spherical supports, and where the activator is designed in such a way that the vertical oscillation damper is released when the threshold value of the vertical oscillation amplitude is reached. The technical result consists in maintaining the functioning of the electronic equipment and software and hardware systems of the NPP automated control system under man-made impacts and earthquakes with a large scale of the amplitude of oscillations of the foundation, on which the structure with the equipment is located or installed. 2 dependent claims, 5 illustrations.

Description

Technical field

The invention relates to means of protection of packaged electronic and electrical equipment, as well as automated control system software and hardware systems (ACS SHS), mostly for nuclear power plants (NPP), from earthquakes and man-made impacts that lead to mechanical oscillations of foundations of structures, as well as to means of protection against the effects of industrial vibration, which leads to mechanical aging of elements of devices making part of ACS SHS and electrical equipment.
There are known ACS SHS, consisting of a network of "Software and hardware (SW&HW)", which are implemented as cabinets, panels, consoles, display workstations, accommodating the identified equipment (units of devices as well as individual electronic, electrical, optical, electromechanical, electrical installation and electrical wiring devices) - see "Standard STO 1.1.1.07.001.0675-2008 of JSC Rosenergoatom Concern "Nuclear power plants, EQUIPMENT, DEVICES, MEANS OF MONITORING AND CONTROL SYSTEMS, General technical requirements, Effective date: 15.02.2009".
The specified standard stipulates the necessity of classification according to seismic resistance and vibration resistance: a) equipment, devices and automation tools, depending on the degree of their responsibility for ensuring safety during seismic impacts and operability after an earthquake, should be assigned to one of three categories of seismic resistance in accordance with NP-031-01, taking into account their safety class as per OPB 88/97; b) depending on the group of operating conditions and the place of installation, the equipment, devices and automation tools should be assigned to one of the four groups of resistance to sinusoidal vibration effects.
Due to the fact that at each facility where ACS SHS is installed there are different operating conditions, for each facility it was necessary to design and qualify for resistance to external effects an individual ACS SHS with individually selected Software and Hardware and element base, which significantly increased the cost of ACS SHS and extended the delivery time. The closest analogue of the claimed ACS SHS is defined as the "Software and hardware complex of automated control system" described in Russian Patent No. 2643210 .
The analogue provides for the use of cabinets, panels, consoles, display workstations, accommodating the identified equipment (units of devices and individual electronic, electrical, optical, electromechanical, electrical installation and electrical wiring devices) installed on plinths and/or seismic protection platforms and/or damping bases, in which the bases for electrical equipment are built, consisting of 3D-compensators, vibration sensors, automatic regulators, programmable controllers that transmit information about the amplitude-frequency characteristics of the vibration of the floor and the SW&HW base (software and hardware) to the network.
This enabled the use of SW&HW qualified for normal external affecting factors (EAF) - in extreme operating conditions in terms of seismic loads and vibration (i.e. the same ACS SHS may be used in different vibration conditions); besides, to increase the reliability of ACS SHS by proactively replacing SW&HW elements whose mechanical aging has approached the threshold value according to the technical certificate, the system is additionally provided with an integrated information platform for controlling mechanical aging of elements, including a programmable controller-comparator of energy spectral density (ESD), which is connected to the information system and contains a database of permissible values of ESD and threshold values of the vibration dose of elements of hardware designed for processing vibration data received from controllers from the bases for electrical equipment, integrating the current ESD values for software and hardware, comparing the current ESD values with acceptable ones and based on data on vibration threshold values for hardware components, and transmitting a signal to the information network about the need to perform routine maintenance on software and hardware that needs to be performed according to vibration indicators.
However, NPP control systems must function not only in the event of earthquakes, but also in the event of man-made factors (IAEA Safety Standard, NS-G-3.1. IAEA, Vienna 2002). The design requirements for the SW&HW certification for resistance to man-made impacts are more stringent than those for the safe shutdown earthquake (SSE); for example, for Kudankulam NPP the design regulates the range of oscillations up to ±14 mm at SSE, while the certification for resistance to an impact of shock waves is required to be held at a range of oscillations ±32 mm (more than twice as much). To protect against mechanical effects from the foundation, the bases for electrical equipment and SW&HW use seismic protection platforms that shield the oscillations of the foundation, but their dimensions are strictly limited by design requirements, since the seismic protection platforms are integrated into cabinets connected in sections.

Disclosure of invention

The problem solved by the invention is as follows: to extinguish large mechanical oscillations in the ACS SHS from man-made impacts and earthquakes, without increasing the overall dimensions of the SW&HW structure. This task is complicated by another circumstance: large-range mechanical oscillations are present in the low-frequency region (1-25 Hz) and are statistically rare, as an SSE, an aircraft impact (AI), an air shock wave (ASW) from an explosion at the facility are rare events, while the continuous industrial vibration that leads to the aging of SW&HW elements is the most significant in the frequency range of 25-50 Hz. Industrial vibration is successfully dampened by 3D-compensators built into seismic protection platforms or bases of the structure, but they cannot dampen large-scale low-frequency oscillations due to dimensional limitations.
Therefore, the technical result of the invention is the assurance of the functioning of electronic equipment and software and hardware systems of the NPP automated control system under man-made impacts and earthquakes with a large range of amplitude of oscillations of the foundation on which the structure with the equipment is placed or installed.
The aforesaid problem and the technical result are achieved by creating a system for damping mechanical oscillations of the bases of structures for the placement and/or installation of electrical equipment and/or software and hardware system of the NPP automated control system, including the base of the structure on which the electrical equipment and/or software and hardware system of the NPP automated control system are installed and/or placed, where the base of the structure is a load-bearing and/or supporting unit, which includes 3D-compensators; moreover, the system additionally comprises at least one load-bearing girder, at least one low-frequency oscillation damping unit mounted between the foundation of the structure for installing the base of the structure and the load-bearing girder(-s), on which 3D-compensators are mounted, where the low-frequency oscillation damping unit has a vertical oscillation damper pre-compressed by a predetermined amount, blocked with a lock of a vertical damping activator, and a horizontal oscillation damper in the form of a movable support mounted on a supporting plate through spherical supports, and where the activator is designed in such a way that the release of the vertical oscillation damper occurs when the threshold value of the vertical oscillation amplitude is reached.
The vertical oscillation damper is implemented in the form of one or many springs.
The vertical damping activator is a mechanism comprising a retainer made of a disc spring that prevents the spring(-s) of the vertical oscillation damper from extension, where the retainer is held in the working position if the vertical movement of the load-bearing girder relative to the supporting plate is less than the structurally determined permissible displacement. Thus, the totality of the above features enables to maintain the functioning of the system in the event of man-made impacts and earthquakes with a large range of the amplitude of oscillations of the foundation of the building or structure in which the NPP equipment is placed and/or installed.

Brief description of drawings

Fig. 1 presents a general diagram of the system for damping mechanical oscillations of software and hardware systems of an automated control system, mostly for NPP. Fig. 2 presents a diagram of a unit that forms the base for electrical equipment and software and hardware systems of an automated control system, mostly for NPP. Fig. 3 presents a diagram of a low-frequency oscillation damping unit. Fig. 4 presents a diagram of a mechanism of the activator unit. Fig. 5 presents a diagram of the structure of 3D-compensators.

Implementation of invention

The solution of the problem is presented in Fig. 1., where ACS SHS equipment (1) is mounted on a mechanical oscillation damping system consisting of interconnected load-bearing/supporting elements or parts of the structure and low-frequency oscillation damping units (6), which are mounted on the foundation (30) through spherical supports (14) mounted on a supporting plate (12).
In essence, the load-bearing parts or supporting elements for ACS SHS equipment (1) are connected or interconnected electrical equipment bases (2), seismic protection platforms (damping bases) (3), plinths (4) and supporting girders (5).
Electrical equipment base (2) is shown in Fig. 2 and consists of 3D-compensators (7) mounted on a load-bearing girder (11), to which an energy spectral density (ESD) comparator controller (8) is attached, in which the effective vibration is automatically compared with the permissible threshold value, and a 3D sensor (10) for recording oscillations of the facility under protection, as well as a 3D sensor (13) for foundation oscillations, which measure the effective vibration value, where the 3D sensor (13) is arranged on the supporting plate (12).
The low-frequency oscillation damping unit (6) is shown in Fig. 3 and consists of compression springs (15) (there may be one or more springs), which in the compressed state are arranged between the load-bearing girder (11) and the movable support (22) located above the spherical supports (14), and also includes an activator (21) of the low-frequency unit, which consists of an anchor (16) rigidly connected to the supporting plate (12), a hook (18) that provides fixing and holding the lock (19) in a given (working) position. The hook (18) is rigidly connected to the load-bearing girder (11). The retainer (19) prevents the springs (15) and the adjusting locking screw (17), which holds the retainer (19) in the working position, from extension, if the vertical movement of the load-bearing girder (11) relative to the supporting plate is smaller than the structurally determined permissible displacement h approximately equal to the value of the working stroke of the 3D-compensator in the vertical direction. In Fig. 3, position I indicates the unit comprising the elements that make up the structure of the activator.
The structure of the activator may have various embodiments. In Fig. 4, unit I is shown on an enlarged scale. Fig. 4 shows an activator in which the retainer is made of a forcibly unscrewed disc spring (19), which will be brought to normal condition (20) and will not prevent the compression springs from actuation after the mutual movement of the load-bearing girder (11) relative to the supporting plate (12) upwards by an amount greater than h. After the compression springs (15) are actuated, the load-bearing girder is raised by an amount sufficient to compensate for large vertical movements of low frequency from man-made impacts. As a man-made impact is a rare event, it is followed by maintenance work, including the forced compression of the springs (15) and restoring the retainer in the working position (19).
The low-frequency oscillation damping unit (6) is compressed in the normal operating mode, and compensation of industrial vibration is exercised through operation of 3D-compensators (7) located on the load-bearing girder.
The structure of 3D-compensators may have various embodiments; Fig. 5 presents one of the embodiments: the 3D-compensator is located in a housing (23), which is rigidly connected to the SW&HW equipment (1), the housing (23) rests through disc springs (24) on the horizontal compensation bearing element (25) located above the spherical supports (26) arranged inside the 3D-compensators and resting on a rigid base (27), which is connected to the bearing girder (11). The disc springs (24) are designed for vertical compensations and are supported by an adjustment sleeve (28), which is attached to an anchor (29), which prevents the SW&HW from tipping over during large fluctuations due to engagement with the base (27). In the horizontal compensation bearing element (25) and/or at the location of the spherical supports (26) on the base (27), spherical pits can be made for the compensator to return by gravity to its original position after the termination of horizontal oscillations.
The compressed low-frequency oscillation damping unit (6) fits the required dimensions of the SW&HW, but under man-made impacts from the foundation there arise large oscillations, which actuate the activator, and the low-frequency oscillation damping unit (6) is extended to the dimensions that allow large oscillations to be shielded. After man-made impacts, the low-frequency oscillation damping unit (6) is reduced to the compressed state and the dimensions of the SW&HW meet the design requirements again.
The essence of the invention is explained by the drawings: Fig. 1-5, where the ACS SHS equipment (1) is mounted on a mechanical oscillation damping system consisting of interconnected electrical equipment bases (2), seismic protection platforms (damping bases) (3), plinths (4) and load-bearing girders (5). In this case, a low-frequency oscillation damping unit (6) is added, which is mounted on the foundation through spherical supports (14) mounted on a supporting plate (12).

Claims

A system for damping mechanical oscillations transmitted from the structural part of built structures to packaged electrical equipment and/or software and hardware systems of the NPP automated control system, including a base on which electrical equipment and/or software and hardware system of the NPP automated control system are installed and/or placed, where the base is a load-bearing and/or supporting unit, which includes 3D compensators, characterized in that the system additionally contains at least one load-bearing girder, at least one low-frequency oscillation damping unit mounted between the foundation of the structure for installing the base of the structure and the supporting girder(s), on which 3D-compensators are mounted, while the low-frequency oscillation damping unit has a vertical oscillation damper pre-compressed by a predetermined amount, blocked with a lock of a vertical damping activator, and a horizontal oscillation damper in the form of a movable support mounted on a support plate through spherical supports, and where the activator is made in such a way that the release of the vertical oscillation damper occurs when the threshold value of the vertical oscillation amplitude is reached.
The system according to claim 1 characterized in that the vertical oscillation damper is made in the form of one or many springs.
The system according to claim 2 characterized in that the vertical damping activator is a mechanism comprising a retainer made of a disc spring, which prevents the extension of the spring(s) of the vertical oscillation damper, where the retainer is held in the working position if the vertical movement of the load-bearing girder relative to the supporting plate is smaller than the structurally determined permissible displacement.