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Why are the coolant tubes of a pressurized heavy water reactor made of zirconium?
Wiki User
∙ 14y ago
At the time of its design, Canada lacked the heavy industry to cast and machine the large, heavy steel pressure vessel used in most light water reactors. Instead, the pressure is contained in much smaller tubes, 10 cm diameter, that contain the fuel bundles. These smaller tubes are easier to fabricate than a large pressure vessel. In order to allow the neutrons to flow freely between the bundles, the tubes are made of a zirconium alloy (zirconium + 2.5% wt niobium), which is highly transparent to neutrons. The zircaloy tubes are surrounded by a much larger low-pressure tank known as a calandria, which contains the majority of the moderator.
Wiki User
∙ 14y ago
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Why is only heavy water used as coolant for nuclear energy and can you use any other coolant used replacing D2O?
Many pressurized water reactors use "regular" water (light water) as a primay coolant. That means that "only heavy water" is not a rule as regards reactor design. Reactor design specifies the coolant to be used.
Why do you keep the Ph of moderator neutral in pressurized heavy water reactor?
This is done in order to limit corrosion of the internal reactor components
Two important functions of heavy water in a candu reactor?
moderator, coolant
Name one type of nuclear reactor?
CANDU, a reactor type designed in Canada which uses heavy water as the primary coolant.
How tritium is formed in a presurized heavy water reactor?
Tritium is formed by the capture of neutrons by deuterium (heavy hydrogen) which is in the heavy water in the moderator and coolant.
What is the coolant used in kalpakkam power station in India?
Kalpakkam has both Thermal reactor (Madras Atomic Power Station) and Fast Breeder Reactor -FBTR and PFBR (Under construction). In MAPS (thermal reactor) it is Heavy Water (D2O) Which acts as a coolant as well as moderator, where as in Fast Breeder Test Reactor (FBTR) and Prototype Fast Breeder Reactor (PFBR) Sodium (Na) is used as coolant. Since there should not any moderators for fast reactors D2O will not be used as coolant in fast reactors.
What is the most common coolant used in nuclear reactors?
The most common coolant used in nuclear reactors is water. There are light water reactors (using "regular" water), and the heavy water kind of reactor.
What is a nuclear reaction coolant?
Presumably you mean nuclear reactor coolant? This is the fluid that transfers the reactor thermal output to the steam raising units in a PWR, or to the turbine in a BWR, in which cases it is natural water. Gas cooled reactors can use carbon dioxide or helium, and CANDU reactors use heavy water.
Are the PHWR and PWR are same?
They are the same in that they don't allow reactor coolant water boiling in the primary water coolant loop. They are different in that in PHWR the moderator is heavy water while in PWR the moderator is normal light water.
The moderator used in the nuclear reactor at Madras atomic power station in Kalpakkam is?
Heavy water(PHWR)--Pressurised heavy water reactor
The advantage of heavy water as coolant over light water in pressurized reactors?
In the CANDU reactor heavy water is used as the moderator. It is a much better moderator than light water because it does not absorb neutrons so strongly, and enables non-enriched uranium to be used. The heavy water moderator is enclosed in a tank with fuel channel tubes, called technically a calandria. The coolant is also heavy water which flows through the tubes and hence past the fuel elements, and then transfers its heat to a light water secondary circuit. In a PWR or BWR light water is used both as moderator and coolant, which is obviously much cheaper and less complicated, but does require uranium enriched in U-235.
Why do you mix 2.5 percent niobium in the coolant tubes of a pressurized heavy water reactor?
This is a metallurgical question and needs a specialist answer. However it is to do with obtaining a material that will withstand the severe neutron flux at the fuel bundle periphery, and the conditions of temperature and pressure in the reactor. Zirconium is always alloyed with small percentages of some other metal, in nuclear applications. In the light water reactors, for fuel cladding and other in-core components, it has been alloyed with tin in US designs and with niobium in Russian designs, but at a lower percentage. AECL must have done some fundamental research and experimentation to arrive at a figure of 2.5 percent. Note that the pressure tubes even with this material will not last a full reactor life, and they can be replaced as part of 'refurbishment'. See the link below particularly question A.16. This series of FAQ may also answer some other queries on CANDU reactors.Note that niobium is also frequently used in steel based alloys to improve its qualities.
