Reactor vessel, design

Brown, Nicholas, Gas-Cooled Reactor Vessel Design and Optimization with COSMOSFloWorks, American Nuclear Society Student Conference, Rensselaer Polytechnic Institute, NY, March 31, 2006. 

In the recent years, maximum operating power level of the reactor is 6 MW with permitted maximum fuel burn-up 9% h.a. Fast neutron fluence 6.31x10 n/cm (En >0.1 MeV) has been reached on the reactor vessel, design value being equal to 7.Ox 10 n/cm. ... 

The use of prestressed concrete vessels for gas-cooled reactors was initiated in Europe. A summary of reactor vessel designs using prestressed concrete technology is shown in Fig. 7. As indicated, vessels having... 

C-E designs reactor pressure vessels and specifies corresponding fabrication methods. C-E has been involved in reactor vessel design and fabrication since the late 1950s, and this proven expertise is reflected in the System 80+ reactor vessel and the satisfactory performance of large numbers of reactor vessels in operating plants. 

The reactor is a PWR type with forced circulation through the primary circuit. Reactor vessel design pressure and temperature are 16.2 MPa and 350°C respectively. The reactor vessel is made of thermal resistant, high strength feritic steel with corrosion-resistant cladding. The reactor vessel is 3.89 meters high and 2.22 m in diameter. 

Design, materials of construction, fabrication methods, inspection requirements, shipment and installation, operating conditions, and inservice surveillance are all components of a program to assure reactor vessel integrity for the plant design lifetime. A complete description of the reactor vessel design is given in CESSAR-DC, Section 5.3. 

Since the System 80+ reactor vessel design complies with the ASME code and other accepted industry codes and standards, and meets the requirements of 10 CFR 50.61, this issue is resolved for the System 80+ Standard Design. 

The reactor vessel design is based on proven historic SFR technology. The most important new feature of the PRISM reactor vessel and internals is that the reactor vessel has no penetrations (below the reactor closure head). This reactor vessel nozzle configuration precludes any large pipe ruptures at or below the elevation of the core. It is a key factor of the PRISM safety systems to keep the core completely and continuously flooded for the entire spectrum of design basis events/accidents. The reactor vessel is filled with liquid sodium and a helium cover gas. 

The reactor vessel design utilises the concept of ring forgings to minimise the number of welds required in manufacture, as is proposed for the Sizewell B PWR. 

New features for the APIOOO have been incorporated into the APIOOO reactor vessel design ... 

The reactor vessel design must enable it to be readily inspected at intervals throughout its life, either directly or by inference from samples placed so as to experience the same or more arduous physical conditions. 

Clearly, the March 2005 reactor vessel design did not meet the 34.8 kPa (5.1 psid) pressure drop goal and thus design modifications would be requited to reduce N2N pressure drop. 

Reactions are conducted in reactors, vessels designed to allow the reactants to come into contact under specific conditions. In order to determine the size of a reactor needed to carry out a specific reaction, we use a material balance equation, written in maximum generality as follows ... 

Industrial appHcations often require that bulk materials or Hquids be weighed in hoppers, silos, tanks, or reactor vessels, referred to collectively as vessels. Because they come in such a wide variety of si2es, shapes, and capacities, scales using these vessels as load receivers are not typically available as standard products. Vessels are usually custom-fabricated to suit a particular appHcation, then mounted on a scale. Some can be mounted on a standard scale such as a bench, portable, or floor scale. More typically, a number of weigh modules are used to support the vessel. This offers the scale designer great flexibiHty but certain precautions are necessary in order to constmct an accurate scale. Some of the more important factors associated with the design of vessel scales are discussed herein. 

Wetox uses a single-reactor vessel that is baffled to simulate multiple stages. The design allows for higher destmction efficiency at lower power input and reduced temperature. Its commercial use has been limited to one faciHty in Canada for treatment of a complex industrial waste stream. Kenox Corp. (North York, Ontario, Canada) has developed a wet oxidation reactor design (28). The system operates at 4.1—4.7 MPa (600 to 680 psi) with air, using a static mixer to achieve good dispersion of Hquid and air bubbles. 

Reactors are designed to be inherently safe based on physical principles, supplemented by redundant equipment and special procedures. Nuclear power benefits from the appHcation of the concept of defense in depth, ie, by using fuel form, reactor vessel, building containment, and emergency backup procedures to ensure safety. 

Structural design drawings for typical critical structures such as the lower elevation of the auxiliary building, reactor vessel, containment, reactor building and substructure, and concrete.. 

Seismic design basis for the reactor vessel (including attachments, pressure boundary, and CRD and internals). 

Another strategy would involve design of the reactor vessel for a pressure rating in excess of any likely emergency system pressure. This assumes we can adequately predict all possible worst case situations, which is doubtful. 

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