Light water circuits

The nuclear fuel pellets are generally filled in thin-walled cladding tubes to hinder leaching by coolant in the reactor core and to prevent release of fission products into the coolant circuit. In light-water reactors, for example, zirconium alloy (zirkaloy) cladding is used. 

Haat extraction The light water in the pressure vessel at high pressure is heated by the core. It is pumped to a steam generator where it boils water in a separate circuit the steam drives a turbine coupled to an electric generator. 

Fig. 4 is a schematic view of the reactor enclosed in a water and concrete shield showing the light water cooling circuit, the helium circuit, and the heavy and light water leakage circuits ... 

The primary cooling circuit comprises a pipe system 24 drawing light water 65 from the water shield, and then circulates it through the heat exchanger 27, and by means of pump 28 conveys the water to the pipe headers 81 (Fig. 

Referring to Fig. 4, the light water thus withdrawn from the leakage chambers 45 through pipes 112 is collected in a sump 113 from which it is again returned to the water cooling circuit A through a pipe 114. ... 

As shown in Fig. 19, the rods 168 respond to a flow Thus, circuit D is broken at the contact 413 thereby switch 331 disposed in the light water cooling pipe 24 76 de-energiang the electromagnetic relay coil 334 causing... 

At the start of the life, the addition of light water to the primary circuit caused a reactivity increase, as expected. Therefore all the systems were conceived... 

The PWR possesses a double cooling circuit. The primary circuit with the main pumps (3) in Pig. 57.8passes (light) water along the fuel rods. The water takes over the heat evolved. 

The experiments were carried out in a 4-ft diam.by 5-lt deep tank of light water. The lattices were hexagonal in shape and placed so as to provide effectively infinite water reflection on all sides. The lattice plates were constructed from Incite. Safety circuits, neutron sources, and BF, counters for monitoring neutron multiplication were adapted from previous experiments of this type on 3.1% enriched uranium-water systems. ... 

The heat produced by controlled fission in the fuel is transferred to the pressurized heavy water coolant and circulated through the fuel channels and steam generators in a closed circuit. In the steam generators, the heat is used to produce light water steam. This steam is used to drive the turbine generator to produce electricity. The nuclear steam supply system (NSSS) is illustrated in Figure 4.2. 

Typical circuit for a boiling light water cooled heavy water moderated reactor. 

When information on the production and transport of the radionuclides in the primary system is requested, it is not sufficient to limit the analyses to those isotopes that are relevant for dose rate buildup such as °Co, Co, and Mn. As will be discussed in the following sections, there are two different possible sources of radionuclides in the primary circuit of light water reactors the materials located permanently in the core region and those located outside the neutron field from which corrosion products are transported to the reactor core and are temporarily deposited there. With regard to the production of radionuclides, the main difference between these two sources is the residence time of the substances in the neutron field, which is equivalent to its activation period for this reason, determination of the element specific activity, i. e. the activity of a given long-lived radionu-... 

The ABV reactor installation is a nuclear steam-generating plant with an integral pressurized light water reactor and natural circulation of the primary circuit coolant. 

The PSRD is an indirect cycle light water cooled tank-type small reactor with an integral design of the primary circuit. Steam generator is located inside the reactor vessel. The PSRD is designed to achieve system simplification, resulting in the reduction of costs for construction, operation and maintenance. The assessments of the plant economy are... 

Coolant weight - the total weight of coolant in the primary circuit at standard ambient temperature 20°C. For light water reactors (PWR and BWR), this value equals the moderator weight. Data providers should enter the actual value in metric tons. 

About 13% of the light water which is circulated over the fuel elements in the most highly rated boiling channel is converted into steam to give a turbine a stop valve pressure of 900 psig. The heavy water moderator has its own cooling and purification circuit and the light water coolant has circuits for water treatment and the detection of fuel element can failure. 

The general design of both types of light water reactor has already been illustrated diagrammatically in Fig. 7.1. The layout of the main components of the primary circuit of a PWR is shown in Fig. 12.3. The circuit consists of the core vessel itself, together with the four steam generators and main... 

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