Chernobyl Fate of Chernobyl's vehicle graveyard

[RobS232]

It would be interesting to review the remediation efforts made at Hiroshima and Nagasaki, now 70 years old, and determine how effective they were, and what impact remediation has had on the million or so people living in those contaminated areas.

 

[mheslep]

It would be interesting to review the remediation efforts made at Hiroshima and Nagasaki, now 70 years old, and determine how effective they were, and what impact remediation has had on the million or so people living in those contaminated areas.

The photos of obliteration immediatly after the Hiroshima bomb are well known. Here's Hiroshima 19 years later, 1964:

Today, residual radiation from the attack is nearly impossible to detect, and no elevated cancer rates of children of survivors are detectable, per this source:
http://www.nap.edu/openbook.php?record_id=1800&page=431

 

[nikkkom]

I agree. Don't mistake "corruption" for "need." Corruption among those in power steals resources from the populace, creating need among the latter. Robbed parts are likely a symptom of that need.

I am _Ukrainian_. I know how things (used to?) work here.

The Zone is a fenced-off and guarded territory. A scavenger can steal a rusting car or two; but a massive operation to salvage about a thousand vehicles reqiures cooperation with authorities.

Basically, what happens is that people in government install their cronies into all positions which generate "streams" (a slang for money which can be... "redirected"). For example, customs, law enforcement, government-owned enterprises (we still have quite a lot of them not privatized since fall of socialism). And the head of government entity which controls the Zone is also such a position.

Our former president assigned his people (and his people's people) to all these positions. And the guy who was assigned to control the Zone was allowed to organize pilfering of its resources as he saw fit.

I would like to say that this no longer happens, but it does, to some extent. The fight to change the overall system is difficult: too many people grew used to using it to accumulate huge amounts of $$$. But I'm drifting off-topic...

 

[mister mishka]

What part of Ukraine are you from nikkkom? I have been to Ukraine several times (Kiev, Odessa, Dnipropetrovsk, Crimea) and I really do love the country and the people there; I've honestly felt more at home there than I have living in some of the western countries. Though I would have to fully learn russian otherwise I won't get that far / integrated..

Regarding Chernobyl, I actually visited that place (and abandon city of Pripyat), and it was quite interesting. It can only be accessed by official guided tours, but yeah the corruption is high in Ukraine, so I wouldn't be surprised if with enough money or influence that you could make some acceptions. I think it was 2 years ago I was on that trip, I remember the guide saying that the vehicle graveyard was now no longer on the tour (so maybe that coincides with the vehicles either being removed / covered in sand). Also we were not allowed to go into the buildings in the city anymore, since they were starting to fall apart. Although the big tour group was not always togethor, so I myself went off into some of them. I climbed the stairs to the top floor suite of the former hotel and I got some really cool pictures, but I don't seem to have them on this computer :(

The radiation levels are actually the lowest inside the buildings, and highest where there is a lot of absorbtion of water. For example putting your Geiger counter over some mossy patchs in between the breaking concrete, it would go up pretty high. The "black forest" area is where there is still to this day insane amounts of radiation levels, and some trees are still actually standing there and still completely black! The concrete roads there are almost completely free of radiation, but they have to keep spraying them every day, because of the winds blowing material back.

Surprisingly there was also a LOT of vandalism in the area and in the buildings. So a lot of scavangers / people have been within the exlusion zone (some have actually been staying and living within Pripyat for weeks!). We were only there for max 2 hours, thus the overall radiation we were exposed to was quite low. But yeah, I don't really feel the security / safety systems for the exlusion zone are that well enforced. So I wouldn't be surpised if some deal was made regarding the scrap, but I find it unlikely since moving all material would be too difficult for it not to get noticed (unless the corruption / "deal" happened at a level higher up in the chain). However the actual reactor itself is quite well sealed off and the security there seems quite high (fences, barbed wire, cameras, gaurds, etc).

 

[mheslep]

...The "black forest" area is where there is still to this day insane amounts of radiation levels, ...

Radiophobia has real, documented impacts - alcoholism, depression - so please don't add to it via hyperbole, especially in the nuclear engineering forum. The commonly found emissions rates for sites all over the Chernobyl area in recent years are available here, and are in the uSv per hour range, aside from equipment and materials used during immediate aftermath of the accident:
http://chernobylgallery.com/chernobyl-disaster/radiation-levels/

 

[mister mishka]

Radiophobia has real, documented impacts - alcoholism, depression - so please don't add to it via hyperbole, especially in the nuclear engineering forum. The commonly found emissions rates for sites all over the Chernobyl area in recent years are available here, and are in the uSv per hour range, aside from equipment and materials used during immediate aftermath of the accident:
http://chernobylgallery.com/chernobyl-disaster/radiation-levels/

Yeah I should ellaborate better, the black forest is an area the guide showed us (by pointing to it from a distance) where there were still high levels of radiation. How he found that out was during winter he went over there wanting to measure amount of radiation of the black trees and say it was quite high and quickly left (and also left his boots). Though I don't know enough on this topic to give any good details or information worthy of this physics forum, I merely wanted to just share an experience.

Thanks for that link though, lots of good information in there!

 

[a.ua.]

johnnyrevCs-137 at Chernobyl has about hit its half-life by now, if I'm not mistaken. However, Cs-137 is most dangerous due to its water solubility, and what do trees drink?
-------------------------------------------------------
but
dangerous strontium 90 and americium 241
easily dissolved and a long half-life. ( half-lives of 432.2 for americium)

 

[Salvador]

All things are somewhat dangerous if one misuses them.I stayed rather long in the sun today , It's June here and this is the time sun has it's highest radiation levels in my location so after a few hours I got pretty burnt.
Chernobyl is actually getting better faster than most people , even experts thought and the wildlife has definitely been doing much much better than at any time in the history of that area simply due to the lack of humans.

I think the really nasty side of radiation is that most of the radioactive dust and particles get into dirt and trees and water faster than anyone can clean up so then they get stuck there and so cause contamination since it's impossible to clean up every square inch of landmass and trees.

 

[Darknoiz]

The vehicles have all been cut up for scrap. In the satellite shot in the third post, top centre. All those dots are the vehicles that once were in the field below. This has been done officially (well, with the knowledge of those who man the checkpoints). Metal reclamation is rife in the Zone. There are teams at work stripping the remains of reactor 5 (there are far fewer cranes around it than there once were), the ships in the dockyard and there are rumours work has even started on the druga 3 array (although I haven't witnessed that myself). Small scale theft, window frames and radiators etc has been going on for years but is periodically clamped down on.

http://chernobylgallery.com/galleries/chernobyl-reactor-5/reactor-5-exterior/

 

[nikkkom]

But yeah, I don't really feel the security / safety systems for the exlusion zone are that well enforced. So I wouldn't be surpised if some deal was made regarding the scrap, but I find it unlikely since moving all material would be too difficult for it not to get noticed (unless the corruption / "deal" happened at a level higher up in the chain).

Yes, that's exactly how it happens: the "deal" happens high enough and material is moved with the knowledge of the guards and their superiors.

 

[nikkkom]

It would be interesting to review the remediation efforts made at Hiroshima and Nagasaki, now 70 years old, and determine how effective they were, and what impact remediation has had on the million or so people living in those contaminated areas.

Those bombs had only a few kilograms of fissile material, and IIRC less than half of it fissioned in the explosion. Chernobyl blast is estimated to vaporize several TONS of reactor core.

 

[mheslep]

Those bombs had only a few kilograms of fissile material, and IIRC less than half of it fissioned in the explosion. Chernobyl blast is estimated to vaporize several TONS of reactor core.

In totaling the radioactive material from the WWII bombs, add to the fission products the couple of moles of MeV neutrons which activate materials immediately adjacent the bomb before dispersal.

The fire and steam explosion from the Chernobyl accident ejected both radioactive and non-radioactive material. Tons of graphite was ejected (not vaporized). Of the radioisotopes released, 50% were inert noble gases, which though dangerous at the time like the prompt radiation from a weapon, the gases also decayed quickly away. Some *27 kg* of long lasting Cs-137 was released.

http://large.stanford.edu/courses/2012/ph241/wessells1/
http://nuclearweaponarchive.org/Nwfaq/Nfaq2.html
http://www.world-nuclear.org/inform...rity/safety-of-plants/chernobyl-accident.aspx

 

[nikkkom]

In totaling the radioactive material from the WWII bombs, add to the fission products the couple of moles of MeV neutrons which activate materials immediately adjacent the bomb before dispersal.

The fire and steam explosion from the Chernobyl accident ejected both radioactive and non-radioactive material. Tons of graphite was ejected (not vaporized).

Reactor had about 200 tons of uranium, and hundreds of tons of graphite. Reactor jumped to estimated 30+ GWt power just before explosion. After explosion, it burned for *days* (there are numerous eyewitness accounts that the flame was very large, comparable to smokestack's height). It means a lot of graphite and fuel turned into microscopic ash-like particles.

 

[Salvador]

Well the army helicopters started flying over very soon after the accident , and from the tapes it can be seen the fire wasn't to the height of the smoke stack because the smoke stack in the RBMK is very high if the flames were that high the helicopter's wouldn't have been anywhere near but we have the tapes from the aftermath showing us the flame size.Ofcourse what happened there the night of the accident is left only in the memories of the ones who were there because no cameras were there to catch any of that.

I think the fire more resembled a cloud of smoke rising from a steel melting furnace than an ordinary fire were something actually chemically combusts and goes up in flames since there isn't much burning material in the reactor hall or anywhere in the active zone its all pretty much steel and concrete but i guess the enormous heat caused by the still ongoing chain reaction and decay is what caused the materials to simply melt and turn themselves into a sparkling soup.
It can actually be seen from the tapes later released that the hot spot is not so much fire as it's a lava like soup that sits in the middle of the reactor like an egg.

 

[mheslep]

Reactor had about 200 tons of uranium, and hundreds of tons of graphite. Reactor jumped to estimated 30+ GWt power just before explosion. After explosion, it burned for *days* (there are numerous eyewitness accounts that the flame was very large, comparable to smokestack's height). It means a lot of graphite and fuel turned into microscopic ash-like particles.

We are discussing the comparison of remediation between WWII atomic attacks and Chernobyl. That is, *nuclear* remediation. What does graphite have to do with this? Or Uranium, how is it significant?

 

[Salvador]

I'm not fully sure of this I hope people with more knowledge will correct me but it seems that a fully loaded and fully working nuclear reactor undergoing meltdown causes much more contamination and after effects than a detonated nuclear bomb, especially the new age ones were the bombs are made more precise and more of the fissile material undergoes chain reaction before the blast rips it apart and the chain reaction ceases.

Also to bear in mind is that in the case of Chernobyl there was very little standing in the way between the reactor fuel and atmosphere , and even with a strong containment structure I think such a blast would have made the structure to collapse and result in what already happened.
after all Fukushima reactors had the safety vessel and yet they too failed to contain the pressure the only blessing that they weren't operating at 100x times their maximum when they went off like Chernobyl was.

 

[nikkkom]

We are discussing the comparison of remediation between WWII atomic attacks and Chernobyl. That is, *nuclear* remediation. What does graphite have to do with this? Or Uranium, how is it significant?

Reactor graphite has significant amounts of C14.

Uranium per se is not too dangerous (it has no intermediate-lived isotopes except U232), but reactor's uranium oxide ceramic pellets, of course, have all sorts of fission products in them. When they melt (or even "merely" strongly heated in an open air fire), those fission products are released.

I don't understand why you are even asking the question, since you for sure know this already.

 

[mheslep]

Reactor graphite has significant amounts of C14.

Uranium per se is not too dangerous (it has no intermediate-lived isotopes except U232), but reactor's uranium oxide ceramic pellets, of course, have all sorts of fission products in them. When they melt (or even "merely" strongly heated in an open air fire), those fission products are released.

I don't understand why you are even asking the question, since you for sure know this already.

Curies from the generated C14 in the entire graphite stack (N content ~30 ppm with 100% conversion) is trivial compared to the Curies from the reactor Cs 137 alone.

The fission product mass from the accident is indeed the health problem. All of it, as I addressed earlier, was calculated and tallied in the dozens of kg range. Whether or not fission product happens to be inclosed in ceramic or buried separately in the dirt, the amount of dangerous radioisotope is not "tons". As you say, you know this from earlier, so it's unclear why you insist on "tons".

 

[nikkkom]

Curies from the generated C14 in the entire graphite stack (N content ~30 ppm with 100% conversion) is trivial compared to the Curies from the reactor Cs 137 alone.

C14 is generated from C13 too, via neutron capture. C13 content in graphite is 1.1%. That's why reactor graphite emits thousands of R/h.

The fission product mass from the accident is indeed the health problem. All of it, as I addressed earlier, was calculated and tallied in the dozens of kg range. Whether or not fission product happens to be inclosed in ceramic or buried separately in the dirt, the amount of dangerous radioisotope is not "tons".

Yes, they are measured in tons. To be more precise, it's about 1-2 tons. RBMK reactors use natural or lightly enriched Uranium. Let's say it's 1% U235. Typical power reactor fissions about the same amount of atoms as fuel enrichment. (Some U235 remains not fissioned; but some U238 gets converted to Pu239 and then fissioned, so it roughly balances out).

RBMK reactor contained a bit less than 200 tons of fuel. 1% of 200 tons is 2 tons. That, very roughly, is how much fission products should have been in that fuel. Definitely not "dozens of kg". Chernobyl reactor was not freshly loaded at the time, the opposite: it was planned to shut down for refueling.

(Edit: googled for it and it seems RBMKs used to use 2% enriched fuel back then, today they use 2.4%. So make that "2-4 tons of fission products")

 

[nikkkom]

Finally found the amount of graphite in RBMK: 1850 tons.

 

[Salvador]

I don't have time to check the other facts you mentioned nikkkom but I know one thing , RBMK reactor isn't shut down when refueling , it continues to operate and the refueling goes on with some 2 to 5 fuel rods changed per day.
They don't shut it down typically they just change the most burnt out fuel assemblies.

 

[nikkkom]

I don't have time to check the other facts you mentioned nikkkom but I know one thing , RBMK reactor isn't shut down when refueling , it continues to operate and the refueling goes on with some 2 to 5 fuel rods changed per day.
They don't shut it down typically they just change the most burnt out fuel assemblies.

The reactor was first brought online 2 years before the accident. Consequently, all fuel bundles were new fuel at the beginning, and now all of them were nearing end-of-life, fully burnt.

Chernobyl Unit-4 shutdown being a planned shutdown is a well-established historical fact. In particular, Medvedev in his book writes: "That day, 25 April 1986, they were preparing to shut down the fourth power-generating unit for regular preventive maintenance".

You are likely correct that it was not planned to be a purely "refueling" outage, I assume there was a plan to transition from initial "uniformly aged" fuel load to the online refueling regime, where different fuel bundles have different ages.

 

[mheslep]

C14 is generated from C13 too, via neutron capture. C13 content in graphite is 1.1%. ..

Trivial compared to the Cs 137, even if all 1200 tons of graphite were ejected, which it was not. About 1/4 of the graphite was ejected. C-14 production in graphite reactors, from all sources (such as C13 n capture) is 200 Ci/GW-yr (http://web.ornl.gov/info/reports/1977/3445605743782.pdf ), or 600 Ci/yr for the Chernobyl reactor, of weak beta radiation with no gamma. By contrast, the Cs-137 released had total activity of 2.2 million Ci (27 kg at 83 Ci/gm) with beta and strong gamma.

...(Some U235 remains not fissioned...)...Definitely not "dozens of kg".

I provided references earlier on the Cs-137 quantity (27 kg) and circling back is tedious. Not all of the radioisotopes were expelled from the reactor in the accident. Half of the radioactivity that was released was in the form of the noble gases, highly radioactive at the time of release, but which decay quickly, disperse, are inert, and not an issue for subsequent remediation, the topic at hand.

Stanford:

...During the Chernobyl explosion, about 27 kg of cesium-137 were expelled into the atmosphere. [2] After the rapid decay of iodine-131, cesium-137 was the predominant source of radiation in fallout from the Chernobyl explosion.

WNA:

It is estimated that all of the xenon gas, about half of the iodine and cesium, and at least 5% of the remaining radioactive material in the Chernobyl 4 reactor core (which had 192 tonnes of fuel) was released in the accident.

A total of about 14 EBq (14 x 10¹⁸ Bq) of radioactivity was released, over half of it being from biologically-inert noble gases.*

Most of that gas would have been Xenon-135 with half life 9.2 hrs.

Also see WNA wrt fuel cycles; the spent fuel composition of a typical LWR, for all fission products at the time of removal, including the gases, the very short half-life and lower radioactivity material is 1.1 mt:

Used fuel 25.5 tonnes containing 240 kg transuranics (mainly plutonium), 24 t uranium (<1.0% U-235), 1100 kg fission products.

The total fission product in an RBMK per ton of initial fuel is going to be substantially less because RBMK burn-up is maybe a 1/3 of a modern LWR (Table 1)

References:
Stanford: The Legacy of Cesium-137 After Nuclear Accidents
WNA: Chernobyl Accident 1986
WNA: Nuclear Fuel Cycle

 

[jim hardy]

Carbon's being such a basic component of DNA is the reason we quit atmospheric weapons testing. See Asimov's "At Closest Range" .
Was the amount of C14 from Chernobyl (and Windscale) significant compared to that from 1950's weapons testing ?

www.alzforum.org/news/research-news/dating-birth-human-cells-carbon-14-runs-rings-around-competition
Analysis of growth rings from pine trees in Sweden shows that the proliferation of atomic tests in the 1950s and 1960s led to an explosion in levels of atmospheric carbon 14. Now, Jonas Frisen and colleagues at the Karolinska Institute in Stockholm have taken advantage of this spike in C14 to devise a method to date the birth of human cells. Because this test can be used retrospectively, unlike many of the current methods used to detect cell proliferation, and because it does not require the ingestion of a radioactive or chemical tracer, the method can be readily applied to both in vivo and postmortem samples of human tissues. In today’s Cell, Frisen and colleagues report how they used the dating method to dismiss the possibility that neurogenesis takes place in the adult human cortex.

 

[mheslep]

Was the amount of C14 from Chernobyl (and Windscale) significant compared to that from 1950's weapons testing ?

600 Curies of C14 from Chernobyl vs the atmosphere? No.

 

[nikkkom]

Trivial compared to the Cs 137, even if all 1200 tons of graphite were ejected, which it was not. About 1/4 of the graphite was ejected. C-14 production in graphite reactors, from all sources (such as C13 n capture) is 200 Ci/GW-yr (http://web.ornl.gov/info/reports/1977/3445605743782.pdf ), or 600 Ci/yr for the Chernobyl reactor, of weak beta radiation with no gamma. By contrast, the Cs-137 released had total activity of 2.2 million Ci (27 kg at 83 Ci/gm) with beta and strong gamma.

From the document you linked with "table 9", from page 11:

So, they measured emissions of 8 and 6 Curies of C14 *from non-exploding, normally operating plants which have no 1800 tons of graphite in them* (they are BWRs/PWRs).
And you want me to believe that blowing up a plant which was online at ~3GWt for 2 years, and then burning up its exposed melted core, will release only 200 Curies of C14? That's impossibly low.

BTW, table 9 is not about C14 generation in graphite, it lists N and O data, not C13.

C14 indeed is a weak beta emitter. Its danger is not coming from its beta; it's coming from the fact that it bioaccumulates, and decay of C14 inside an organic molecule destroys said molecule, no matter how weak the emitted beta.

 

[nikkkom]

Also see WNA wrt fuel cycles; the spent fuel composition of a typical LWR, for all fission products at the time of removal, including the gases, the very short half-life and lower radioactivity material is 1.1 mt:

|Used fuel 25.5 tonnes containing 240 kg transuranics (mainly plutonium), 24 t uranium (<1.0% U-235),
|1100 kg fission products.

The total fission product in an RBMK per ton of initial fuel is going to be substantially less because RBMK burn-up is maybe a 1/3 of a modern LWR (Table 1)

Thus, you are saying that 25.5 tonnes of LWR spent fuel contains 1100 kg fission products. And you are saying that RBMK will be ~1/3 of that. Thus, 25.5 tonnes of RBMK fuel contains ~350 kg fission products. 190 tons of RBMK fuel, then, contains ~2600 kg of fission products. Sounds right in my range of estimates.

 

[mheslep]

Trivial compared to the Cs 137, even if all 1200 tons of graphite were ejected, which it was not. About 1/4 of the graphite was ejected. C-14 production in graphite reactors, from all sources (such as C13 n capture) is 200 Ci/GW-yr (http://web.ornl.gov/info/reports/1977/3445605743782.pdf ), or 600 Ci/yr for the Chernobyl reactor, of weak beta radiation with no gamma. By contrast, the Cs-137 released had total activity of 2.2 million Ci (27 kg at 83 Ci/gm) with beta and strong gamma.I provided references earlier on the Cs-137 quantity (27 kg) and circling back is tedious. Not all of the radioisotopes were expelled from the reactor in the accident. Half of the radioactivity that was released was in the form of the noble gases, highly radioactive at the time of release, but which decay quickly, disperse, are inert, and not an issue for subsequent remediation, the topic at hand.

Stanford:WNA:
Most of that gas would have been Xenon-135 with half life 9.2 hrs.

Also see WNA wrt fuel cycles; the spent fuel composition of a typical LWR, for all fission products at the time of removal, including the gases, the very short half-life and lower radioactivity material is 1.1 mt:

The total fission product in an RBMK per ton of initial fuel is going to be substantially less because RBMK burn-up is maybe a 1/3 of a modern LWR (Table 1)

References:
Stanford: The Legacy of Cesium-137 After Nuclear Accidents
WNA: Chernobyl Accident 1986
WNA: Nuclear Fuel Cycle

Sorry, that's Table 5 in the reference, not 9, showing total C 14 from all sources at 200 Ci per GW yr.

From the document you linked with "table 9", from page 11:

View attachment 101883

So, they measured emissions of 8 and 6 Curies of C14 *from non-exploding, normally operating plants which have no 1800 tons of graphite in them* (they are BWRs/PWRs).
And you want me to believe that blowing up a plant which was online at ~3GWt for 2 years, and then burning up its exposed melted core, will release only 200 Curies of C14? That's impossibly low.

BTW, table 9 is not about C14 generation in graphite, it lists N and O data, not C13.

C14 indeed is a weak beta emitter. Its danger is not coming from its beta; it's coming from the fact that it bioaccumulates, and decay of C14 inside an organic molecule destroys said molecule, no matter how weak the emitted beta.

 

[mheslep]

Thus, you are saying that 25.5 tonnes of LWR spent fuel contains 1100 kg fission products. And you are saying that RBMK will be ~1/3 of that. Thus, 25.5 tonnes of RBMK fuel contains ~350 kg fission products. 190 tons of RBMK fuel, then, contains ~2600 kg of fission products. Sounds right in my range of estimates.

As you know, I am not "saying"; the reference WNA and not me, which I took the trouble to quote, gives typical LWR fission product mass. You also now know, from the other references, for purposes of remediation around Chernobyl, that 27 kg of Cs 137 is the relevant figure, not the total mass of the fission products generated inside the reactor, much of which never left the reactor, or that which existed in the form of noble gases which decayed and dispersed within hours or days of the accident.

 

[nikkkom]

As you know, I am not "saying"; the reference WNA and not me, which I took the trouble to quote, gives typical LWR fission product mass. You also now know, from the other references, for purposes of remediation around Chernobyl, that 27 kg of Cs 137 is the relevant figure, not the total mass of the fission products generated inside the reactor, much of which never left the reactor, or that which existed in the form of noble gases which decayed and dispersed within hours or days of the accident.

I will remind you where your exchange started.
I said:

me>>> Those bombs had only a few kilograms of fissile material, and IIRC less than half of it fissioned in the explosion. Chernobyl blast is estimated to vaporize several TONS of reactor core.

You responded:

you>> Tons of graphite was ejected (not vaporized). Of the radioisotopes released, 50% were inert noble gases, which though dangerous at the time like the prompt radiation from a weapon, the gases also decayed quickly away. Some *27 kg* of long lasting Cs-137 was released.As I see it, you were objecting to my statement, seeing it as exaggeration of Chernobyl. Note that neither my statement nor your response contained any statements limiting discussion to todays' remediation concerns. In any case, both nuclear explosions and reactor accidents are EQUALLY affected by such facts as "some fission products are noble gases and thus much less dangerous".

Now after our exchange, when we both dug out and refreshed data, it is clear that my statement was in fact UNDERstating Chernobyl releases. There were not some "tons" of graphite and reactor core. There was 1850 tons of graphite. And not known exactly, but large fraction of it burned up and ended up outside. There were also 190 tons of spent fuel, which included more than 2 tons of fission products (not all of them Cs-137, true). It also burned after the explosion; and a part of it definitely melted (and possibly even vaporized) during the power excursion. Tons, and likely tens of tons of this fuel ended up outside the reactor. For one, liquidators SAW THE FUEL lying outside of the building, hundreds of meters from the reactor.

My phrase that "Chernobyl blast is estimated to vaporize several TONS of reactor core" did not adequately describe the magnitude of this release.