Reactor auxiliary systems

Because the reactor is basically a water boiler, process systems are required which clean and control the chemistry of the water in the reactor vessel as well as protect the reactor core. Called the reactor auxiliary systems, these systems may be divided into two general 

Auxiliary systems used during normal plant operation include 

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The reactor auxiliary systems are similar to those found on other PWRs and typically include a primary water volume control and inventory system, a primary water purification system, radioactive liquid and gaseous effluent treatment systems, and a ventilation system. At low power levels, many of these systems may be required only on an intermittent basis and would be valved out during periods of autonomous operation. 

The primary system, the reactor coolant pressure boundary, the safety systems and the high-pressure components of the reactor auxiliary systems are enclosed in the primary containment, a cylindrical concrete structure with an embedded steel liner. The primary containment is a pressure-suppression type with two major compartments a drywell and wet well. The drywell includes the volume that surrounds the reactor pressure vessel and the second shutdown system rooms. A partition-floor and cylindrical wall separate the drywell from the wet well. The lower part of the wet well is filled with water that acts as the condensation pool and the upper part is a gas compression chamber. 

The CAREM nuclear island is located inside a pressure suppression containment system. The building surrounding the containment is in a single reinforced concrete foundation mat. It supports all structures with the same seismic classification in one block, allowing the integration of the RPV, the safety and reactor auxiliary systems, the fuel elements pool and other related systems. This building acts as a secondary containment. 

Additionally, the reactor building volume is reduced remarkably by the use of the compact PCV and simplified reactor auxiliary systems. 

In this approach accident cases and design recommendations can be analysed level by level. In the database the knowledge of known processes is divided into categories of process, subprocess, system, subsystem, equipment and detail (Fig. 6). Process is an independent processing unit (e.g. hydrogenation unit). Subprocess is an independent part of a process such as reactor or separation section. System is an independent part of a subprocess such as a distillation column with its all auxiliary systems. Subsystem is a functional part of a system such as a reactor heat recovery system or a column overhead system including their control systems. Equipment is an unit operation or an unit process such as a heat exchanger, a reactor or a distillation column. Detail is an item in a pipe or a piece of equipment (e.g. a tray in a column, a control valve in a pipe). 

The selection requirements for each of the components of the SCWO system for treating a variety of waste types comes from environmental regulations, waste characteristics, and cost and safety criteria. Similar to the bench-scale experimental design, the major components to be included in the SCWO design involve three main subsystems (influent introduction, reactors, and effluent removal systems). Other auxiliary systems such as heat exchangers and effluent exhaust systems must also be designed. In addition, for scale-up operations, the waste pretreatment and handling systems have to be considered. Fig. 10 shows a schematic of a complete system. 

The control performance of the heat-integrated reactor-column system shown in Fig.. 5.9 deteriorates as the auxiliary rehoiler provides less and less heat to the column. The reason is that uncontrolled variations in the steam pressure of the waste heat boiler affect the heat supplied to the column. When these variations are of the same order of magnitude as the total heat supplied by the auxiliary reboiler, the latter cannot compensate properly for the variations. Part of the prob-... 

PTGL-processes (table Ia,b,c) can be characterized by their operating principle (pyrolysis, gasification or liquefaction) and reaction conditions, their type of reactor and method of heat supply and the possible presence of auxiliary systems. The selection of a particular process will ultimately be based on its proven reliability on one hand and on the quality of the process output on the other [ ]. ... 

Figure 2. Schematic diagram of the reactor cooling systems consisting the main cooling system, auxiliary cooling system and vessel cooling system of the HTTR...

Besides it was required to develop and modify core components (fuel sub-assemblies, control rod guide tubes and control rods), to explore and modify electrical drives of sodium pumps, to modify a reactor refuelling system, to construct advanced failed fuel detection systems, to design and construct advanced reactor vessel integrity inspection systems, reactor vessel and auxiliary primary sodium pipeline displacement measurement systems, to remarkably improve water-sodium reaction detection systems of the water-sodium steam... 

At present, mistakes of personal are caused deficiencies of procedure for auxiliary reactor systems, especially if these mistakes are not identified promptly, maybe significant at that time, when the reactor main system fail will be took place. 

All systems and components which must fulfill, with a high level of confidence, their lOCFRlOO-related radionuclide control functions under design basis conditions are located inside buildings or structures which are designed to withstand the impact from tornado-generated missiles. The major portions of the Reactor Buildings, Reactor Auxiliary Buildings, and Reactor... 

Once the reactor has been placed in operation there will always be active particles within the air passages. To prevent these active particles from entering the Reactor Building, a basic requirement of the reactor air system is that there always be a flow of air in the proper direction. Upon failure of the main exhaust blowers and the auxiliary fans, this flow will he induced by whatever stack draft is available. 

The main exhaust blowers are started manually within the Blower and Fan House. Tp promote safe operation of the reactor,air system,both of the auxiliary fans start automatically on failure on the main blowers, and one may then be shut down manually. However, in the event of failure of the one left... 

Loss of reactor auxiliary cooling water system... 

The time schedule of HTR-10 construction is shown in Table3. The reactor building construction v ill be lasted two and half year and scheduled to complete in the end of 1997. In parallel, the manufacture of the components and installation of the main components, equipments and auxiliary systems will be close followed the progress of the building construction and scheduled to complete in the end of 1998. The first criticality of the reactor is planed to be reached in the besinninu of 1999... 

The nuclear part of the plant (i.e. the reactor and its auxiliary systems - the nuclear island ) had been supplied by the Babcock Wilcox company. The architect engineer, Bums Roe, had built the remainder of plant. 

The performance of reactor systems, sodium systems, control rod drive mechanisms and other safety related systems and auxiliary system were generally satisfactory. The primary and secondary sodium purity was maintained below the plugging temperature of 105 C. The four sodium pumps and Aeir drives are operating well and have logged 83,293 h, 70,615 h, 88,878 h 69,201 h. 

DRAGS direct reactor auxiliary cooling system... 

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