Control buildings areas

Based on the results of the qualitative assessment, the decision was made to construct a new control building of blast-resistant design with more separation distance from both the cycle gas compression and feed purification areas. Construction of a new control building was deemed the most appropriate option since the control building spacing and design were considerably out of... 

The latest designs for onshore installations cater for a centralized control room, well distanced from the operating facility with sub control areas as part of a distributed control system (DCS). The sub-control areas are closer to the processes but contain fewer personnel and process control systems for the overall plant, so the overall risk level for the facility from a major incident is lowered. The outlying control buildings (sometimes referred to as PIBs or SIHs) still need to be sited against impacts from explosions and fires. 

Control rooms have evolved into control buildings containing support services and people that may include a break area, restrooms, locker rooms, small laboratories, maintenance shops, conference/training room and offices. These control room/buildings continue to grow in size due to the consolidation of the control of several process units into one control room and the inclusion of their support facilities and staff. 

To protect the control room area from incidents occurring in the support areas, the control room area should be separated from the support areas by minimum 1-hour fire-rated partition walls. All penetrations of the walls, floors, ceilings, and roof for cables, etc. should be closed with an approved sealant having a fire resistance rating of at least one-hour. Approved y4-hour rated (Class B) fire doors equipped with self-closing devices should be installed on all openings between the control room and other portions of the building. 

Active external fire exposure protection for control buildings is seldom needed since the primary protection is the passive spacing distance between the building and the process areas and the building s noncombustible construction. 

When controlled nitridation of surface layers is required, as for example in the modification of the chemical properties of the surface of a support, the atomic layer deposition (ALD) technique can be applied." This technique is based upon repeated separate saturating reactions of at least two different reactants with the surface, which leads to the controlled build-up of thin films via reaction of the second component with the chemisorbed residues of the first reactant. Aluminium nitride surfaces have been prepared on both alumina and silica supports by this method wherein reaction cycles of trimethylaluminium and ammonia have been performed with the respective supports, retaining their high surface areas." This method has been applied to the modification of the support composition for chromium catalysts supported on alumina." ... 

To achieve LP-3 and LP-4, certain LP-1 and LP-2 measures should be in place. For example, access to a central analysis center and to filter and air handler rooms needs to be controlled. Vulnerable areas should be isolated. Arguably, the most likely areas in buildings from which toxic substances can be introduced to the building s air are public entrance lobbies, mailrooms, and loading docks or receiving areas. 

There are barriers and ventilation systems (Fig. 1) for the prevention of incorporation and the spread of contamination inside the building and into the environment. The facility is divided into two main building areas a process building for handling of Pu and an auxiliary building for inactive auxiliary functions (e.g., ventilation, electrical systems, automatic control systems). 

In addition to the state-controlled building codes, a number of other important codes having legal standing are in force. These cover areas of architectural and engineering practice, such as... 

The structural complex at the center of the plant comprises the reactor building and the turbine building. The second complex contains the switchgear equipment, the systems for radioactive waste treatment and storage, the hot workshop, staff amenities, the main control room and the entrance to the controlled access area. The third structural complex consists of the plant service systems the circulating water supply systems, the emergency diesel generators, the cold workshops and the demineralized water system. 

Zinc and/or zinc coatings are relatively immune to corrosion in such indoor areas as offices, shops, schools, heated warehouses, hotels, and industrial production/assembly areas where the humidity is controlled. In areas subject to occasional condensation, such as unheated buildings, sports arenas, and garages, a low rate of corrosion may be expected. 

The potable water day tank is above the main control room area. It is filled as and when required but is otherwise isolated from external sources thus any leakage is limited to the day tank volume. The potable water piping from the tank is sized so that even in the event of a pipe rapture the leak rate would be modest. The pipes are routed within the maimed spaces, so that any leakage would be detected quickly. The potable water is thus not a flooding hazard to the safety signifieant equipment within the clean Auxiliary Building. 

This subsection should provide relevant information on the heating, ventilation, air conditioning and cooling systems in a format as described in paras 3.65-3.70. It should include the ventilation systems for the control room area, the spent fuel pool area, the auxiliary and radioactive waste area and the turbine building (in boiling water reactors) and the ventilation systems for engineered safety features. 

Different functional areas in a control building (e.g., offices and the control room proper) should be separated by fire-resistant walls that extend from the floor to the roof. 

The control building foundation site should be higher than the surrounding areas so that a spill or surface drainage flows away from the control building... 

Electrical switchgear, circuit breakers, switches, and small transformers are normally grouped together in a building or Motor Control Center (MCC). Climate controlled buildings may also be required to house minicomputers, transducer banks, and other instrument interfaces. Putting this equipment in a building protects it from fires and explosions in the process area. 

In freezing climates, the strainer, control valve manifold, and necessary system drains should either be located in a heated area within the control building, in a heated cubicle, or be insulated and heat traced. 

The battery limit is a geographic boundary which deflnes the manufacturing area of the process. This includes process equipment and buildings or structures to house it but excludes boilerhouse facilities, pollution control, site infrastructure, etc. 

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