Boiling-Water Reactor

(redirected from BWRS)
Also found in: Dictionary, Acronyms.

boiling-water reactor

[¦bȯil·iŋ ¦wȯd·ər rē′ak·tər]
(nucleonics)
A nuclear reactor in which the coolant is water, maintained at such a pressure as to allow it to boil and form steam. Abbreviated BWR.

Boiling-Water Reactor

 

a nuclear reactor in which the core is cooled by a boiling coolant, usually water. Boiling-water reactors may be used in single-loop schemes of atomic power plants, in which steam produced in the reactor is conducted directly to a turbine. The favorable heat-transfer conditions that may be achieved by boiling water in the reactor core make it possible to attain high specific loads in the core. Factors that limit the increase of the specific power of a boiling-water reactor are the heat flux per unit length of the fuel element at which melting of the nuclear fuel occurs and the heat flux per unit surface at which the critical heat transfer point occurs, causing coating of the surface by a vapor film, a sharp reduction of the heat transfer, and, consequently, burnout of the fuel element jacket.

There are boiling-water reactors of the vessel and tube types. In vessel-type reactors, water is also the moderator, whereas in tube-type reactors the boiling occurs in tubes located within the moderator blocks. Separation of the water-steam mixture takes place either inside the reactor vessel or in external drum separators. The separated water is mixed with the cooler feed water and passes into the evaporator part of the core, where it evaporates partially.

In the USSR, two tube-type reactors are being successfully used at the I. V. Kurchatov Beloiarsk Atomic Power Plant. These reactors have power of 100 and 200 megawatts (MW), respectively, and represent the first industrial application of steam superheating by nuclear means. In the first block reactor, which was started up in 1964, the heat of boiling water in evaporating channels is used to generate secondary steam in steam generators, which is then superheated in the reactor channels of the second loop. The radiation safety of both heat-transfer loops, which was confirmed by operation, made possible the use in the second unit, which was started up in 1967, of single-loop circulation of the boiling water and superheated steam, which is distinguished by simplicity and economy. A power plant with an experimental boiling-water reactor of the VK-50 vessel type, with a power of 50 MW and natural circulation of the coolant, has been in operation in Dimitrovgrad since 1965.

A large number of boiling-water reactors have been designed in various countries—for example, the Oyster Creek vessel-type boiling-water reactor (USA), with a power rating of 515 MW, in which the devices for steam separation and the multiple circulation loop for the coolant are located within the vessel. Positive operational experience with boiling-water reactors, the possibility of providing high power output from a single unit, and the use of superheated steam, as well as the simplicity and economy of atomic power plants containing boiling-water reactors, make this type of reactor very promising in world power production. The Leningrad, Kursk, and Chernobyl’sk unit electric power plants, with carbon-uranium tube boiling-water reactors and with a power of 1,000 MW each, are under construction.

V. P. VASILEVSKII

References in periodicals archive ?
BCW Entertainment will be led by veteran entertainment industry leader Eric Green, who is being promoted to president of BWR, effective immediately.
Both the PWR and BWR, representing together more than 80 per cent of the commercial nuclear reactors worldwide, are light water (H2O) moderated and use uranium enriched at 3 n 5 per cent in fissile 235U isotopes.
To get to Fukui from Kyoto you take a semi-express train called 'Thunderbird' which skirts the western edge of the lake to Tsuruga, where there are two genpatsu: one, a Boiling Water Reactor (BWR) built in 1969, was the first in Fukui.
The Fukushima plant features boiling water reactors, known as BWRs, which operate at lower pressures than the other main light-water reactor technology, the pressurized water reactor.
In India, NPCIL currently operates 20 nuclear power reactors - as compared to 54 in Japan - with an installed capacity of 4,780 MW, including two Boiling Water Reactors (BWRs) and the rest Pressurised Heavy Water Reactor (PHWRs).
Cefais bwrs arian smart gan un ffrind, a dwi'n meddwl amdani bob tro y talaf am rhywbeth.
Experimental and analytical modeling of natural circulation and forced circulation BWRs; thermal-hydraulic, core-wide, and regional stability phenomena.
The joint ventures will lead the partners' efforts to expand their presence in the global market for advanced boiling water reactors and in the development of next-generation reactors such as simplified BWRs.
Tenders are invited for Repair & Maintenance Of Stacker, Barrel Reclaimer, Bwrs, Transfer Cars At Ohp & Bmp Yard In Rmhp.
Petawn i'n Frenhines Cymru, neu'n Garwyn am Ddiwrnod, byddwn yn rhoi caniatad i bob plentyn gael mynediad am ddim i bob sioe blant, a byddwn yn rhoi'r arian i'r cwmniau theatr o bwrs y wlad.
A diolch i Will Pierce, Penmachno am lythyr difyr arall yn sn am y bara popty brics, ac mai iddo fo, dolur ar bwrs buwch oedd y 'gafod' neu'r 'gawod'.