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Russia Set To Extend Life of Nuclear Reactors Past Engineered Life Span
Harperdog writes "Yikes! Russia is extending the lifetime of nuclear power reactors beyond their engineered life span of 30 years, including the nation's oldest reactors: first-generation VVERs and RBMKs, the Chernobyl-type reactors. This goes against existing Russian law, because the projects have not undergone environmental assessments. 'Many of the country's experts and non-governmental organizations maintain that this decision is economically unjustifiable and environmentally dangerous — to say nothing of illegal. The Russian nuclear industry, however, argues that lifetime extensions are justified because the original estimate of a 30-year life span was conservative; the plants have been significantly upgraded; and extensions cost significantly less than constructing new reactors.'"
The Chalk river reactor.
Except it does:
During life-extension projects, engineers determine which components are in need of replacement, and which can remain in service if maintained regularly. Some parts of a reactor, however, cannot be replaced -- including the reactor casing and its internal elements, the graphite stack (found in RBMK reactors), primary coolant circuits, primary coolant pumps, and biological shield systems. These parts are crucial for the safe operation of a reactor, particularly a first-generation reactor.
In the case of the Kola nuclear power plant in northern Russia, for example, the reactor casing should be replaced in order to ensure safer operation, but that cannot be done without building a new reactor. In addition, the proximity of the fuel assemblies to the steel walls in the VVER-440 reactor tank -- such as those used in two of Kola's reactor units -- results in higher neutron irradiation than in other types of reactors, so the walls of the VVER-440 become brittle more rapidly.
You can't handle the truth.
Material decay under long-term exposure to radiation, most likely. Also, as new technology becomes available, they may expect the plant to be out-dated and no longer worth the necessary modifications to match newer standards after thirty years.
So far the US has granted extensions like this to more than SIXTY reactors. How many has Russia given out so far?
http://money.cnn.com/2011/03/15/news/economy/nuclear_plants_us/index.htm
Sorry, that's a fairy tale.
1) There's no way a 'room which nobody knows about' can exist in a nuclear power plant.
2) Especially if it contains components from the freaking primary contour. And the secondary cooling contour is absolutely safe - you can drink water from it.
3) There's no way radiation levels can be large enough to cause significant irradiation in several minutes. Absolutely none at all - primary cooling water is radioactive, but not that much (it's continuously monitored).
4) Power plant operators after Chernobyl are _very_ careful. For a reason.
But what do I know? After all, I have actually worked on a Russian nuclear power plant.
Most metals become brittle when irradiated.
Someone will be along with more details then I can recall offhand.
I would just design the plant to run with brittle metals from day one. Nothing that can't be solved with thicker walls (in many cases anyhow).
Modern reactors use a neutron shield that goes with the fuel basket. It can be replaced and greatly decreases vessel embrittlement by becoming the sacrificial element to first absorb/slow the errant neutrons.
The problem is with shutdown and startup. This needs to be done with control as things become harder and have less flex.
That sounds, really, really, impressive and scary to the uninformed. But it's not actually. If your friend exceeded his quarterly allowed dose, it means he took the equivalent of a few transcontinental flights or chest X-rays. (I.E. practically nothing.)
No, you're not a sissy. Just badly misinformed and prone to EWW RAD1AT10N !1!11! syndrome.
As I understand it, the RBMK reactors are already a long way from meeting modern safety standards. They have no containment building, they still have a positive void coefficient, the monitoring and control systems are quite limited despite being upgraded and this can't really be fixed, there appear to be a bunch of single points of failure that can't be fixed either, and so on.
Modern updates greatly reduced the positive void coefficient. It used to be wildly positive (4.7), which allowed running unenriched uranium on a non-heavy-water reactor. Now it's around 0.7, which gives you a lot more room for error.
The controls are considerably upgraded: no more graphite tips on the control rods, more manual control rods, more neutron absorbers, no more safety overrides, and more.
There aren't many single points of failure, but the safety margin and redundancy is much lower than western designs. A PWR can be leaking like a sieve and still maintain adequate cooling; a RBMK can hit trouble with only a few broken pipes, and as you say, there's no way to mitigate it, since it's part of the design.
They actually do have some some containment. It's not a heavy-duty all-encompassing concrete bunker like a western reactor, but there are high pressure management channels, steam condenser pools, etc. Any routine blowout will be contained... Just don't pull a Chernobyl. :)
I'd say RBMK safety has been upgraded from "Insanely Irresponsible" to "Poor".