Nuclear-reactor vessels

Concrete nuclear reactor vessels, of the order of magnitude of 15-m (50-ft) inside diameter and length, have inner linings of steel which confine the pressure. After fabrication of the liner, the tubes for the cables or wires are put in place and the concrete is poured. High-strength reinforcing steel is used. Because there are thousands of reinforcing tendons in the concrete vessel, there is a statistical factor of safety. The failure of 1 or even 10 tendons would have little effec t on the overall structure. 

Slides Springs of various types multi-leaf springs on trucks, automobiles, steam locomotives, etc. light pressure vessels - e.g. aeroplane fuselages cheap pressure vessels - e.g. water tanks, nuclear reactor vessels metal rolling stand. 

The energy produced in a nuclear reactor vessel is the result of a nuclear fission (atom splitting) process that occurs when sufficient nuclear material is brought together (critical mass). Under these circumstances, a chain reaction occurs and an external supply of neutrons is not required. A nuclear fuel control rod system raises or lowers the nuclear fuel (which is contained within fuel rods) inside the reactor vessel. 

The United States, ASME code, is divided into sections which cover unfired vessels, boilers, nuclear reactor vessels, and vessels constructed of fibre-glass-reinforced plastics. A comprehensive review of the ASME code is given by Chuse (1977) and Yokell (1986) see also. Perry et al. (1997). 

Snznki K and Sato I, Developments of large integral forgings of nuclear reactor vessel and their manufacturing technology . The Japan Steel Works Technical Review, 1992,47,93-98. 

Low-intensity ultrasonic waves are used for nondestructive probing to locate flaws in materials for which complete reliability is mandatory, such as those used in spacecraft components and nuclear reactor vessels. When an ultrasonic transducer emits a pulse of energy into the test object, flaws reflect the wave and are detected. Because objects subjected to stress emit ultrasonic waves, these signals may be used to interpret the condition of the material as it is increasingly stressed. Another application is ultrasonic emission testing, which records the ultrasound emitted by porous rock when natural gas is pumped into cavities formed by the rock to determine the maximum pressure these natural holding tanks can withstand. 

ASME Code Case N-557, "In place dry annealing of a PWR nuclear reactor vessel," March, 1996. USNRC Generic Letter 92-02, Revolution of Generic Issue 79 Unanalyzed reactor vessel (PWR) thermal stress during natural convection cooling. ... 

McGowan J.J. An assessment of the beneficial effects of warm prestressing on the fracture properties of nuclear reactor vessels under severe thermal Shock. Westinghouse nuclear energy systems, WCAP-9178 (1978)... 

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. 

The proper choice of material is now a quite different one. Reinforced concrete is now the best choice - that is why many water towers, and pressure vessels for nuclear reactors, are made of reinforced concrete. After that comes pressure-vessel steel - it offers the best compromise of both price and weight. CFRP is very expensive. 

The previous chapter described the consequences of a nuclear reactor accident. Chemical process accidents are more varied and do not usually have the energy to melt thick pressure vessels and concrete basemats. The consequences of a chemical process accident that releases a toxic plume, like Bhopal did, are calculated similarly to calculating the dose from inhalation from a radioactive plume but usually calculating chemical process accidents differ from nuclear accidents for which explosions do not occur. 

Nuclear PSAs contain considerable uncertainty associated with the physical and chemical processes involved in core degradation, movement of the molten core in the reactor vessel, on the containment floor, and the response of the containment to the stresses placed upon it. The current models of these processes need refinement and validation. Because the geometry is greatly changed by small perturbations after degradation has commenced, it is not clear that the phenomcn.i can be treated. 

There is a close kinship between the chemical process industry and the nuclear electric power industry. In tact once the physics of nuclear reaction was established the rest is chemistiy and hc.it ii an.sfer. The word "reactor" is from chemistry for the location the reaction takes place.. nuclear reactor consists of a vessel in which a nuclear reaction heats water to make steam to drive a turbine o generate electricity. Thus the primary components are pipes, valves, pumps heat exchangers, and water purifiers similar to the components found in a chemical plant. Following the success of WASH-1400, PSA was used to analyze the chemical proce.ssmg of nuclear fuel and. aste preparation for disposal. 

The most serious accident tliat Ciui occur in a nuclear plant is a reactor core meltdown. In a core meltdown, the enclosed gases physically melt through tlie reactor vessel, and once contacting with cooler liquids or vapors either in a cooling jacket or in the outer enviromnent, cause a physical e. plosion to occur. However, tlie hazard caused by the e. plosion itself is minimal and more localized compared with the release of radioactive material that accompanies such an accident. 

The fuel in a nuclear fission reactor is generally "U atoms arranged appropriately in a reactor vessel. Neutrons instigate fission of nuclei ofatoms and liberate energy. The energy output may be controlled either by regulating the fuel and/or adjusting the neu-... 

Pressurised water nuclear reactors require metals that will have a high degree of corrosion resistance to pure water at around 300°C. Laboratory testing of materials for this application have included potentiostatic polarisation experiments designed to clarify the active-passive behaviour of alloys as well as to establish corrosion rates. Since pressure vessels are used for this work, it is necessary to provide sealed insulated leads through the autoclave head . 

Many dozens of industrialized countries now employ nuclear reactors for power generation, and some countries produce more electrical power by nuclear reaction than by fossil fuel combustion (France is an example). The United States, however, has the largest installed capacity of nuclear-powered boiler plants (in the year 2000 there are more than 120 nuclear reactor power plants in the United States). Nuclear power is also widely used for marine duty in both commercial and naval vessels. 

Reactor vessel Reactors produce intense heat, and those employed in large nuclear power boiler installations (typically 800-1,000 MWh) may have 50,000 to 60,000 sq ft of heat transfer surface area with a heat flux of from 150,000 to 500,000 Btu/ft2/hr. 

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