Nuclear power reactors heavy water reactor

There are various types of nuclear power reactors, including boiling water reactors (BWR) and pressurized water reactors (PLWR or LWR), which are both light-water reactor (LWR) designs and are cooled and moderated by water. There also are pressurized heavy-water reactor (PHWR or HWR) designs. 

All over the world, 432 nuclear power reactors are under operation and more than 36 GW of electricity could be produced as of December 31, 2001. There are several types of reactors such as boiling water reactor (BWR), pressurized water reactor (PWR), Canada deuterium uranium (CANDU), and others. In these reactors, light water is normally used not only as a coolant, but also as a moderator. On the contrary, in CANDU reactors, heavy water is taken. It is widely known that the quality control of coolant water, the so-called water chemistry, is inevitably important for keeping the integrity of the plant. 

The main advantage of a heavy water reactor is that it eliminates the need for building expensive uranium enrichment facilities. However, D2O must be prepared by either fractional distillation or electrolysis of ordinary water, which can be very expensive considering the amount of water used in a nuclear reactor. In countries where hydroelectric power is abundant, the cost of producing D2O by electrolysis can be reasonably low. At present, Canada is the only nation successfully using heavy water nuclear reactors. The fact that no enriched uranium is required in a heavy water reactor allows a country to enjoy the benefits of nuclear power without undertaking work that is closely associated with weapons technology. 

In the CANDU heavy-water reactor the dominant source of tritium is the deuterium activation reaction of Eq. (8.53). The data given in Prob. 3.3 for the Douglas Point Nuclear Power Station provide a basis for estimating the rate of production of tritium in the heavy-water moderator and coolant ... 

This order applies to all varieties of reactors including, but not limited to light water moderated reactors, heavy water moderated reactors, liquid metal cooled reactors, gas cooled reactors and short-pulse transient reactors. Space reactor power and propulsion systems and critical facilities require special design criteria. Attachment 4 is reserved for Nuclear Safety Design for critical facilities and space reactors. 

Tborium is tbe nuclear fuel resource available in India in plentiful quantities to sustain a large power programme. At present, tbe design and development of Advanced Heavy Water Reactor (AHWR) and Compact High Temperature Reactor (CHTR) are underway for utilization of tborium. Incorporation of simplified and passive systems is one of tbe features of these reactors. Tbe R D work related to these reactors is being carried out in BARC. 

Following a general survey of the basic types of nuclear power reactor, separate chapters are devoted to each of the principal designs—the gas-cooled graphite-moderated reactor, the light-water-moderated reactor, the heavy-water-moderated reactor, and the fast reactor. Each chapter includes a discussion of the evolution of the design and a detailed description of one or more typical power plants. 

LEWIS W.B. Designing heavy water reactors for neutron economy and thermal efficiency. DL-42, AECL-II63, Proceedings p.lO, Symposium on Nuclear Power, D.A.E. India, Bombay, January I96I. 

I would like to make a general comment about the different heavy water reactor designs which have been presented. As the cost of the nuclear parts of the power stations becomes smaller, the opportunity to make substantial further savings becomes less, and I have gained the impression that the differentials between the generating costs of the different reactors presented are marginal. 

Heavy water reactors. 2. Nuclear power plants — Accidents. I. International Atomic Energy Agency. II. Series. 

TNA PRO EG 12/134. Specific proposals for Steam Generating Heavy Water Reactor (SGHWR) and High Temperature Reactor (HTR) development. Status of SGHWR with Particular Reference to Safety. The Nuclear Power Group Limited, British Nuclear Design and Construction Limited, November 1973. Thermal Reactor Policy, House of Commons Debate (Fifth series), 25 January 1978, Vol. 942, cc. 1391-1392. 

One of the most significant sources of change in isotope ratios is caused by the small mass differences between isotopes and their effects on the physical properties of elements and compounds. For example, ordinary water (mostly Ej O) has a lower density, lower boiling point, and higher vapor pressure than does heavy water (mostly H2 0). Other major changes can occur through exchange processes. Such physical and kinetic differences lead to natural local fractionation of isotopes. Artificial fractionation (enrichment or depletion) of uranium isotopes is the basis for construction of atomic bombs, nuclear power reactors, and depleted uranium weapons. 

The next presentations discussed chemical problems encountered in the nuclear power industry. S. R. Hatcher (Atomic Energy of Canada Ltd., Pinawa) gave a general review covering the chemistry of established and novel nuclear fuels, heavy-water production, and reactor operation. 

Because early Canadian reactors used heavy water, and because it is also fundamentally the most efficient moderator, Canada naturally adopted the heavy water reactor for the development of a nuclear power system. By using heavy water both as moderator and as coolant, and by refuelling with the reactor at power, it was possible to develop the CANDU system to operate efficiently and economically with natural uranium fuel. This in turn resulted in the simplest possible fuel cycle. 

The basic design of most nuclear reactors is similar, but several types of reactors are used throughout the world. In the United States most reactors use plain water as the coolant. Reactors using ordinary water are called light water reactors. Light water reactors can be pressurized to approximately 150 atmospheres to keep the primary coolant in the liquid phase at temperatures of approximately 300°C. The heat from the pressurized water is used to heat secondary water to generate steam. In a boiling water reactor, water in the core is allowed to boil. The steam produced powers the turbines directly. Heavy water reactors use water in... 

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