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Domain: aecl.ca
Stories and comments across the archive that link to aecl.ca.
Comments · 20
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Re:Time for a serious effort on renewables
Even better, AECL is currently developing the ACR-1000 which is based on the proven CANDU design but delivers more power, has improved safety mechanisms, is simpler to build and operate, etc. etc. Unfortunately, the government has decided to sell off AECL, so the future of these reactors seems nebulous at the moment.
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Re:I was going to ask...Actually it's not the normal backup power -- it's a secondary, emergency backup power: The NRU reactor has eight independent main cooling pumps. In addition to the regular power supply, four of these pumps have a DC motor connected to backup power supplies - the normal backup supply. Two of those pumps, P-104 & P-105, are used to provide emergency core cooling and are to be connected to an additional back-up power supply, known as the Emergency Power Supply (EPS).
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Re:It's not as terrifying as it soundsJudging from a more technical explanation, the issue with the pumps seems to have been widely misreported. The NRU reactor has eight independent main cooling pumps. In addition to the regular power supply, four of these pumps have a DC motor connected to backup power supplies - the normal backup supply. Two of those pumps, P-104 & P-105, are used to provide emergency core cooling and are to be connected to an additional back-up power supply, known as the Emergency Power Supply (EPS). The issue is that those last two pumps, for unclear reasons, were not connected to the Emergency Power Supply (a backup to the backup) when they should have been.
The reactor is fifty years old, and has been subject to many many upgrades; the regulator reviews the state of things every couple years and asks for upgrades to keep pace with modern nuclear safety standards. The most recent review asked for this secondary backup, but it was discovered on a routine inspection that it had not been installed when they were under the impression it had been.
The talk of "pump installation" is actually about installing new motor starters for the pumps that are connected to the EPS; the first new motor starter had already been installed when the Government intervened to bring the reactor back online. The second one is being prepared and will now be installed in an upcoming scheduled maintenance. (Even under normal operation, the reactor is taken offline every two week for a few days.) -
Re:Got to love it...
Damn Internet:
http://www.aecl.ca/Science/CRL.htm -
CANDU
I fail to see why the majority of people insist on ignoring the superior technology of the AECL's CANDU reactor. It uses unenriched fuel, does not produce bomb grade waste and cannot meltdown.
Maybe because it's not American its not valid or allowed? Sort of like the Avro Arrow?
There is no shortage of uranium for CANDU reactors.
http://www2.nrcan.gc.ca/es/erb/erb/english/View.as p?x=493
http://www2.nrcan.gc.ca/es/erb/erb/english/View.as p?x=497&oid=1188#Fact_Sheet
TFA is a load of BS. -
Steaming Pile of Bull
I'll believe that we have working fusion reactors when the AECL is selling them.
If this guy had a working fusion reactor, people would be throwing money at him, he wouldn't be lobbying corporations with questionable investment policies.
This is totally bogus. I can't believe that people are even entertaining the concept.
Power generation involves generating power, not consuming it. Any fusion reactor that requires a significant power input is guaranteed to fail. Period. -
Re:At least here in Quebec...
Hydro-Québec owns and operates Gentilly-2, a nuclear reactor located near the community of Trois-Rivières in Québec.
Photo - http://www.aecl.ca/index.asp?menuid=21&layid=3&csi d=75&miid=211
Maybe Celines parents drove to to the hospital in Trois-Rivières ? -
Re:Uranium is a finite resource
They're hideously expensive to build, which is why they for the most part aren't built anymore.
Canada has a thriving industry in building and exporting nuclear reactors. Ever hear of CANDU? -
Re:TWO PROBLEMS - who pays for the power stations?
Nuclear power can't pay it's own way in the world. That's why they stopped building reactors about twenty years ago.
There's not really much to debate here, because you're flat-out, 100% wrong. Canada constructs and exports plenty of nuclear reactors for power plants all over the world.
Link. -
Re:heroism in the face of bad design and decisions
I currently work at the Pickering CANDU station east of Toronto, but not in a design/analysis role. My previous experience is with analysis and operation of Boiling Water Reactors. I'm very interested in the Advanced CANDU (ACR-700), though. It's a sweet design.
There are several evolutionary changes in the ACR-700, relative to the previous generation CANDU-6. First, it uses fuel enriched up to 2% U-235 as opposed to natural U. Second, it retains heavy water as a moderator/reflector in the calandria, but uses light water as coolant in the primary heat transport system. Third, the fuel bundle design's been optimized to include two different pin diamaters, and the center pins are actually poisoned with dysprosium.
The end result of all those changes is that the lattice spacing of the pressure tubes, running through the calandria, has been decreased. The pitch was apparently tuned to achieve a slight, negative void coefficient.
The canonical site for ACR-700 information is http://www.aecl.ca/
You can find a lot of other info at:
http://www.nrc.gov/reactors/new-licensing/license- reviews/design-cert/acr-700.html
Scroll down to the bottom, and you'll see a link for other Pre-application documents. That's where you want to go for more technical info. -
Re:Blame Canada
Well speaking as a Canadian, You can lick my balls, proverbially of course... I must apologize for that remark, since of course it is the Canadian way.
And FYI some of the best things to come out of Canada, in no particular order are:
-Mike Meyers
-Jim Carrey
-Basketball (Basketball History)
-Hockey (Hockey History)
-Dr. Frederick Banting (discoverer of insulin)
-The CanadaArm (which you guys have used in your shuttles for ages now)
-Margaret Atwood
-The Light Bulb
-The Telephone, By Mr. Bell
-TV
-The safest Nuclear Reactor out there, the CANDU
Hell, I'll just stop now and you can look at this list: Some Canadian inventions or this Famous Canadians -
Don't forget CANDU
Canada has had safe reactors for many years using a natural uranium fuel system that is delivered in packages to the core while it is running.
CANDU Nuclear Power Plants -
Re:Breader reactorsWell, you offered... so I guess I will correct you.
American-style nuclear reactors use a process called the Pressurized Water Reactor (PWR). This reactor uses pressurized water as the modulator and coolant. The water flows over the reactor core, heating up from the reaction in the fuel. The heat in this water is transfered (through a transfer chamber) to uncontaminated water, which boils and goes through a turbine. In fact, the non-nuclear side of the reactor (turbine hall, etc.) is not unlike that of a coal/oil/gas plant. One disadvantage of this setup, however, is that to keep the reaction going using standard water as the modulator, the uranium has to be enriched. (Which is expensive, and causes security concerns - as enriched uranium could be used for several other things).
CANDU technically stands for "Canada Deuterium Uranium". The CANDU reactor varies from its American counterpart by using non-enriched uranium. It makes up for the lack of reactivity by using deuterium ("Heavy Water") as its modulator and coolant. Being heavy, heavy water acts as a better modulator and can keep the reaction going with the lower grade of uranium.
There are really two disadvantages of the CANDU design over the PWR. First, PWR reactors can simply reach higher power levels than the CANDU. For example, the Bruce Nuclear Power facility runs 4 CANDU reactors. They have turbines rated to 1000MW, but can only output about 850MW. A PWR could go up to the full 1000MW. Additionally, heavy water has issues of its own. It is pretty expensive to create (although, through processes that occured in the 1970s, Canada is sitting on more heavy water than it knows what to do with.) On a day to day level, the iradiation of deterium produces a considerable amount of a 3rd isotope of water, tritium. Unlike light and heavy water, tritium is radioactive. As tritium is a beta emitter, contamination cannot be detected with the standard gamma portals at nuclear power sites - urine tests are a nessessity. Thankfully, processes exist to strip used heavy water of the tritium, so that it can be used again.
Now, the CANDU has several advantages as well. The first major one is the use of non-enriched fuel. This adverts much of the risk of dealing with weapons grade uranium fuel. Additionally, it helps keep the costs down.
Another neat aspect of the CANDU design is that it can be refuelled at full power. PWR reactors require at least a partial shutdown of a unit to refuel.
So, that's a basic overview of the CANDU design. A side note is that AECL (Atomic Energy of Canada Limited), the creators of the CANDU, are recently soliciting a new design, called the ACR-700 ("Advanced CANDU Reactor"). Unlike the previous design, it does use light water as the coolant. However, it retains the use of heavy water as the modulator.
Finally, to touch on two points in the above message (and my references will support this)...
The CANDU reactor is NOT a breader/fast reactor.
The CANDU reactor does NOT consume its own plutonium
It is simply a different type of reactor for electricity generation.
References:
Atomic Energy of Canada Limited - Creators of the CANDU reactor design. Corperate homepage.
British Energy - Fact File on Reactor Types
Atomic Energy of Canada Limited - Press release regarding commissioning of new CANDU reactor in China (August 13, 2002)
Bruce Nuclear Power Facility - Tiverton, Ontario.
-legolas. -
Re:Breader reactorsWell, you offered... so I guess I will correct you.
American-style nuclear reactors use a process called the Pressurized Water Reactor (PWR). This reactor uses pressurized water as the modulator and coolant. The water flows over the reactor core, heating up from the reaction in the fuel. The heat in this water is transfered (through a transfer chamber) to uncontaminated water, which boils and goes through a turbine. In fact, the non-nuclear side of the reactor (turbine hall, etc.) is not unlike that of a coal/oil/gas plant. One disadvantage of this setup, however, is that to keep the reaction going using standard water as the modulator, the uranium has to be enriched. (Which is expensive, and causes security concerns - as enriched uranium could be used for several other things).
CANDU technically stands for "Canada Deuterium Uranium". The CANDU reactor varies from its American counterpart by using non-enriched uranium. It makes up for the lack of reactivity by using deuterium ("Heavy Water") as its modulator and coolant. Being heavy, heavy water acts as a better modulator and can keep the reaction going with the lower grade of uranium.
There are really two disadvantages of the CANDU design over the PWR. First, PWR reactors can simply reach higher power levels than the CANDU. For example, the Bruce Nuclear Power facility runs 4 CANDU reactors. They have turbines rated to 1000MW, but can only output about 850MW. A PWR could go up to the full 1000MW. Additionally, heavy water has issues of its own. It is pretty expensive to create (although, through processes that occured in the 1970s, Canada is sitting on more heavy water than it knows what to do with.) On a day to day level, the iradiation of deterium produces a considerable amount of a 3rd isotope of water, tritium. Unlike light and heavy water, tritium is radioactive. As tritium is a beta emitter, contamination cannot be detected with the standard gamma portals at nuclear power sites - urine tests are a nessessity. Thankfully, processes exist to strip used heavy water of the tritium, so that it can be used again.
Now, the CANDU has several advantages as well. The first major one is the use of non-enriched fuel. This adverts much of the risk of dealing with weapons grade uranium fuel. Additionally, it helps keep the costs down.
Another neat aspect of the CANDU design is that it can be refuelled at full power. PWR reactors require at least a partial shutdown of a unit to refuel.
So, that's a basic overview of the CANDU design. A side note is that AECL (Atomic Energy of Canada Limited), the creators of the CANDU, are recently soliciting a new design, called the ACR-700 ("Advanced CANDU Reactor"). Unlike the previous design, it does use light water as the coolant. However, it retains the use of heavy water as the modulator.
Finally, to touch on two points in the above message (and my references will support this)...
The CANDU reactor is NOT a breader/fast reactor.
The CANDU reactor does NOT consume its own plutonium
It is simply a different type of reactor for electricity generation.
References:
Atomic Energy of Canada Limited - Creators of the CANDU reactor design. Corperate homepage.
British Energy - Fact File on Reactor Types
Atomic Energy of Canada Limited - Press release regarding commissioning of new CANDU reactor in China (August 13, 2002)
Bruce Nuclear Power Facility - Tiverton, Ontario.
-legolas. -
Re:Slippery SlopeCanada's reputation for answering the call of the internation community in times of need has been going downhill for over 10 years now, as our military falls further and further into decline. It's a sad, sad state of affairs. I mean, it's to the point now where we cannot rely on our own coast guard for search and rescue, due to the decrepit fleet of Sea King helicopters they've been flying for over thirty years. Do you not think that the country with the longest coastline in the world should have an adequate means of peforming these duties!? I agree that since the start of the cold war, we've been under the protective umbrella of the DEW line (later NORAD) and the U.S. in general, but they needed our strategic position guarding the northern polar route as much as we needed them.
arrr...
and another thing. CANDU reactors can burn plutonium. It hasn't been in the news lately, but do you recall the plan to burn surplus Russian and American MOX fuel (95% uranium oxide, 5% plutonium oxide) in CANDU reactors? Check out this info page at the Atomic Energy Canada Limited website. The project update from January 22, 2001 refers to burning MOX with 3% and 5% weapons-grade plutonium content. The idea is to actually eliminate all this surplus fissile material which resulted from the START treaties and their ilk.
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Re:Slippery SlopeCanada's reputation for answering the call of the internation community in times of need has been going downhill for over 10 years now, as our military falls further and further into decline. It's a sad, sad state of affairs. I mean, it's to the point now where we cannot rely on our own coast guard for search and rescue, due to the decrepit fleet of Sea King helicopters they've been flying for over thirty years. Do you not think that the country with the longest coastline in the world should have an adequate means of peforming these duties!? I agree that since the start of the cold war, we've been under the protective umbrella of the DEW line (later NORAD) and the U.S. in general, but they needed our strategic position guarding the northern polar route as much as we needed them.
arrr...
and another thing. CANDU reactors can burn plutonium. It hasn't been in the news lately, but do you recall the plan to burn surplus Russian and American MOX fuel (95% uranium oxide, 5% plutonium oxide) in CANDU reactors? Check out this info page at the Atomic Energy Canada Limited website. The project update from January 22, 2001 refers to burning MOX with 3% and 5% weapons-grade plutonium content. The idea is to actually eliminate all this surplus fissile material which resulted from the START treaties and their ilk.
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Also burns plutonium...
...a great way of getting rid of weapons grade stuff you might have around...
(former IT guy from AECL makers of the CANDU) -
How about a nuclear reactor?
Plutonium has been created in nuclear reactors, how about we destroy it in nuclear reactors?
CANDU reactors can safely burn fuel consisting of mixed uranium and plutonium. If all the CANDU reactors around the world were fed the appropriate mixture, the entire 270 ton stockpile of plutonium could safely be disposed of within a couple years. -
How about a nuclear reactor?
Plutonium has been created in nuclear reactors, how about we destroy it in nuclear reactors?
CANDU reactors can safely burn fuel consisting of mixed uranium and plutonium. If all the CANDU reactors around the world were fed the appropriate mixture, the entire 270 ton stockpile of plutonium could safely be disposed of within a couple years. -
Can do with CANDU
Yes, breeder reactors have been around for some time, and we've been using them a lot here in Canada, and selling them to other countries (such as India) for a while too. Modern-day CANDU reactors can handle:
- slightly enriched uranium (SEU)
- recovered uranium (RU), a by-product of conventional reprocessing of spent Light Water Reactor (LWR) fuel
- mixed oxide (MOX) fuels, which dispose of plutonium from nuclear weapons
- thorium
This is what I learned from the Internet, more info at the Atomic Energy of Canada Limited (AECL) website for any interested. It's interesting actually.
~Sentry21~