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22 years ago this month (26th April 1986) Chernobyl pumped out vast amounts of radiation that still affects many people today.

In Belarus the children may not live a long life. Even if they do they have a high risk of cancer and illnesses like early on-set osteoporosis.


In my country (UK) some sheep farmers in the Welsh hills are still legally obliged to test their sheep for radiation. (Chernobyl's radiation is still even now residual in the soil.)

Our governments have never told us the true breadth or level of contamination that covered our countries or cities.

But at least in my country most of the contamination was dispersed.

The 'World Health Organisation' (W.H.O.) believed 2/3rds of a million people close to Chernobyl were at life threatening risk from the contamination.

After 22 years a new generation of people are with us.


The charities that offer Belarus children holidays abroad reckon that 4 weeks outside of the irradiated area can add 2 years to the life of each child.


This April remember those people in and around the Chernobyl area.



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A forgotten tragety. Thanks for the reminder cRunchy

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It's good to be back amongst friends and colleagues

A forgotten tragety. Thanks for the reminder cRunchy

And it all was almost swept under the carpet. I think a lot off diseases came from
that nuclear blast too.

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A forgotten tragety. Thanks for the reminder cRunchy

And it all was almost swept under the carpet. I think a lot off diseases came from
that nuclear blast too.

Not a blast, but a reactor meltdown.

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It's good to be back amongst friends and colleagues

. . . Thanks for the Post - Reminder cRunchy

here's a link for You too . . .

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BOINC Wiki . . .

Science Status Page . . .

Why they didn't have a containment building is beyond me, it all could have been avoided.

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Safety and the control systems were very primitive, and not in the recognised engineering requirements then, I think

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It's good to be back amongst friends and colleagues

There was an incident at Three Mile Island in western PA and the containment building did what is was supposed to do, contain the radiation.

Here is the NRC's take on Chernobyl.

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one good thing came from it,the 30 km zone is now a natural reserve...any one up for hunting?

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Scorpions - Wind Of Change

one good thing came from it,the 30 km zone is now a natural reserve...any one up for hunting?

I read in the article that entrances to the affected area are guarded.
You would not want to eat anything grown or foraging/living in that 30Km zone because of long term exposure to the radiation still left in the ground.

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Interesting....

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one good thing came from it,the 30 km zone is now a natural reserve...any one up for hunting?

I read in the article that entrances to the affected area are guarded.
You would not want to eat anything grown or foraging/living in that 30Km zone because of long term exposure to the radiation still left in the ground.

bah..whats a little fallout ;)

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Scorpions - Wind Of Change

Interesting....

Very interesting indeed! Thank you. Очень интересно!

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Interesting....

Very interesting indeed! Thank you. Очень интересно!

Thanks for the post. It's largely forgotten and sad. I thought it was interesting that the surrounding area was in the "Life After People" program on the history channel...

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Safety and the control systems were very primitive, and not in the recognised engineering requirements then, I think

Maybe, but the meltdown was caused by the failure of both staff as well as the procedure used to do their low-load testing. The idea was in the event of a total loss of external power to the station that the unit could power the cooling water pumps in the core until the emergency diesel generators had enough time to run up (Roughly 30 to 50 seconds).

An initial test failed, so this was the second time it was done after modifications were carried out.

The operators on duty that evening were relatively unskilled in Nuclear plants and a situation developed where the earlier high load operation developed a large quantity of Iodine 135 was still in the process of decaying to Xenon 135, and the xenon damps the entire nuclear process. This had the effect of dropping the output of the reactor very quick and very low (About 30MW).

The control rods were extracted to quicken the reaction back up, but the load only increased to 200MW. Because of the damping effect of the Xenon the rods were extracted too far, but they continued with the test.

The water pumps to be driven by the turbine were turned on, and the water further reduced the output. Because the auto control rods were still in the maximum position, a decision was made to remove manual control rods to increase the reaction. At this stage the only thing that kept the units load low was the internal levels of Xenon 135.... I work at a power station and at this stage I'd be extremely worried as theoretical fuel should have been keeping the unit at max power, not a low load as was being experienced!

The test was carried out and the main cooling water pumps were tripped, leaving the turbine supplied pumps the only source of cooling. Cooling was not the iddue - the water absorbs neutrons, and slows the reaction down. The sudden loss of the main cooling water supply removed the damping effect, thus increasing the reaction. Also because steam was removed from the turbine, the cooling loops temperature rapidly increased, causing steam bubbles. Because the steam absorbs a LOT less neutrons than the water it came from, the increase in steam further fed the reaction.

Dont forget that the auto control rods that would normally help limit this reaction were removed, as were some manual ones as well. Some of the rods which would have operated quickly (3 seconds) to help reduce the reaction had been transferred from automatic control to manual control. There is some debate as to weather the insertion of the rods would have been enough, but at this stage any auto help would probably have helped reduce rather than increase the reaction

The operators then ordered a SCRAM of the reactor, but it was too late. The main design flaw of this reactor is that it takes up to 20 seconds to insert the control rods, and in the initial stages the rods displace the reaction-dampening cooling water in the core to a greater extent than the control rods reduce the reaction, so by inserting the control rods they actually sped up the reaction even more. The first meter or so of the rods are simply hollow (With a graphite tip), so the first meter or so of travel yields no reducing effect at all.

The heat and force of the reaction at this stage began to break fuel rods and housing assemblies, so the control rods could not be inserted fully, but by then it was probably too late and the reactor's output rapidly went poast 10 times its normal output, fracturing more rods, and eventually the lid of the reactor failed, venting all the water as steam, and reducing cooling and dampening in the core to vurtually nil. The graphite in the core and tips of the control rods ignited when exposed to air further increasing the force of the explosion

A sad day for everyone affected.

Dave

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Safety and the control systems were very primitive, and not in the recognised engineering requirements then, I think

Maybe, but the meltdown was caused by the failure of both staff as well as the procedure used to do their low-load testing. The idea was in the event of a total loss of external power to the station that the unit could power the cooling water pumps in the core until the emergency diesel generators had enough time to run up (Roughly 30 to 50 seconds).

An initial test failed, so this was the second time it was done after modifications were carried out.

The operators on duty that evening were relatively unskilled in Nuclear plants and a situation developed where the earlier high load operation developed a large quantity of Iodine 135 was still in the process of decaying to Xenon 135, and the xenon damps the entire nuclear process. This had the effect of dropping the output of the reactor very quick and very low (About 30MW).

The control rods were extracted to quicken the reaction back up, but the load only increased to 200MW. Because of the damping effect of the Xenon the rods were extracted too far, but they continued with the test.

The water pumps to be driven by the turbine were turned on, and the water further reduced the output. Because the auto control rods were still in the maximum position, a decision was made to remove manual control rods to increase the reaction. At this stage the only thing that kept the units load low was the internal levels of Xenon 135.... I work at a power station and at this stage I'd be extremely worried as theoretical fuel should have been keeping the unit at max power, not a low load as was being experienced!

The test was carried out and the main cooling water pumps were tripped, leaving the turbine supplied pumps the only source of cooling. Cooling was not the iddue - the water absorbs neutrons, and slows the reaction down. The sudden loss of the main cooling water supply removed the damping effect, thus increasing the reaction. Also because steam was removed from the turbine, the cooling loops temperature rapidly increased, causing steam bubbles. Because the steam absorbs a LOT less neutrons than the water it came from, the increase in steam further fed the reaction.

Dont forget that the auto control rods that would normally help limit this reaction were removed, as were some manual ones as well. Some of the rods which would have operated quickly (3 seconds) to help reduce the reaction had been transferred from automatic control to manual control. There is some debate as to weather the insertion of the rods would have been enough, but at this stage any auto help would probably have helped reduce rather than increase the reaction

The operators then ordered a SCRAM of the reactor, but it was too late. The main design flaw of this reactor is that it takes up to 20 seconds to insert the control rods, and in the initial stages the rods displace the reaction-dampening cooling water in the core to a greater extent than the control rods reduce the reaction, so by inserting the control rods they actually sped up the reaction even more. The first meter or so of the rods are simply hollow (With a graphite tip), so the first meter or so of travel yields no reducing effect at all.

The heat and force of the reaction at this stage began to break fuel rods and housing assemblies, so the control rods could not be inserted fully, but by then it was probably too late and the reactor's output rapidly went poast 10 times its normal output, fracturing more rods, and eventually the lid of the reactor failed, venting all the water as steam, and reducing cooling and dampening in the core to vurtually nil. The graphite in the core and tips of the control rods ignited when exposed to air further increasing the force of the explosion

A sad day for everyone affected.

Dave

There are, I believe 2 key points.

As a part of the test, the automatic safeties were turned off. This means that the auto control rods were being controlled manually.

The second is that in some places in the structure there was a steel roof with tar on top. Once a fire was started underneath sufficient to melt the tar on the roof, the seams in the roof metered the tar into the fire at a rate that was keeping a nice blaze going (firefighters nightmare) making the fire harder to put out.

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BOINC WIKI