FIG. 70. Modularization of the containment liner plate assembly, Shin-Wolsong 2, Republic of Korea.
one lift by using a 1300 t rigging crane, thereby reducing the number of lifts to shorten the overall plant construction duration (refer to Fig. 70).
By replacing many works done in high places by ground level works, this modularization contributes to promoting the overall safety of construction. This method also simplifies connections with auxiliary buildings, since connecting provisions, such as penetration sleeves for piping and electrical wire, have been already attached to the ring modules.
5.2. DIESEL GENERATOR BUILDING — CONSTRUCTION ACTIVITIES AND TECHNOLOGIES
5.2.1.Conventional methods
In earlier plant design layouts, the emergency diesel generators were contained within other building structures. Current plant designs typically house the diesel generators and associated support equipment in a designated separate structure.
Typically, every nuclear unit has at least two diesel generators that provide emergency electrical power should all off-site electrical power be lost. The diesel generators have turbochargers that supply combustion air. To ensure that they start, emergency air storage tanks supply high pressure air to turn the diesel. As with most rotating mechanical equipment, water cooling systems and oil lubrication systems are used. These generators provide power to special safety electrical distribution panels, only when needed. The panels in turn supply power to the emergency pumps, valves and fans.
Figures 70 and 71 show a diesel generator and Fig. 73 shows a diesel generator room.
As discussed in earlier paragraphs, in the previous methods of construction, tape measures, levels, etc. were used to locate the position of the walls and floors to be constructed. Reinforcing steel bars were wired together to form an array of steel encompassing the floor or wall area. Penetrations of steel piping, boxed openings, etc. were arranged within the array of steel to provide for penetration openings for the pipe, cable pan or conduit raceways, and HVAC ductwork. Forms, typically of wood, were constructed to enclose the reinforcing steel and frame the volume where concrete was placed to form the walls. Steel plates with anchors welded on the inside face were attached to the forms to provide a surface for later attachment of supports, and restraints for equipment, piping, electrical raceway; etc. The same process was performed for the floors of the building structure, except the top surface remained open.
Because the process of construction of the concrete wall and floor structures required forming and temporary support until the concrete achieved a strength to be self-supporting, temporary openings in the floors and walls were required to enable movement of the plant mechanical and electrical equipment, and interconnecting piping and electrical cables into their required locations. This limited the size of the assemblies that could be made off-site.
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FIG. 71. Diesel generator (view one).
FIG. 72. Diesel generator (view 2).
After the floors and walls had cured sufficiently, the large equipment was moved into position. Assembly was then completed within the room structures, along with the installation of the piping; electrical raceways and cable; HVAC ductwork; etc. along with their structural supports to hang and restrain movement.
By using the stick-build method of construction, each of these thousands of single component fitting tasks occurred simultaneously on the same physical floor space at various distances above the floor. Extensive scaffolding was required to provide access to locations above the floor, leaving progressively decreasing workspace in which to perform the tasks.
5.2.2.Advanced methods
With the advances in lift capacity of cranes, the diesel generators and associated support equipment become a target area for complete room modularization.
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FIG. 73. Diesel generator room.
5.3. CONTROL ROOM COMPLEX — CONSTRUCTION ACTIVITIES AND TECHNOLOGIES
5.3.1.Conventional methods
Advances in electronics technology and human factors engineering have reduced the building area required for control rooms. This is true in the nuclear power industry as well as in most other industries using central control technologies.
In a typical conventional two-unit NPP with a common control room for both units, control room sizes were approximately 15 m × 30 m or larger. Most designs included a combination of vertical panels and bench boards. Equipment indications and controls were organized by system. Annunciators with a sound alarm were usually placed above the control board or at the top part of the control board. The plant computer was used to provide alarms to alert the operator to problems.
Less frequently used equipment was usually placed on panels in the back part of the control room or behind the main control board, as shown in Fig. 74 and Fig. 75. In the past, the control technology was analogue with hardwired connections, mimic displays, hand switches for individual equipment control, and console displays of dedicated hardware gauges and indicators. Collectively, these features required larger rooms. In a modern control room, shown in Fig. 76 , advances have resulted in the use of digital technology with fibre optics, overall plant monitoring with industrial TVs, visual display units (i.e. monitors), all typically contained in reduced size housings.
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FIG. 74. Conventional control room.
FIG. 75. Panels in conventional control room.
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