Reprise on nuclear fuel rod coolant requirements : LUSENET : TimeBomb 2000 (Y2000) : One Thread

In a recent post by Robert Wood (now lost somewhere in cis-lunar space) I recall a statement to the effect that hot fuel rods placed in a water bath would cool down enough in a few days to require at most replacement of evaporated water in the bath.

How is this compatible with the quote below from the AF's Midnight Crossing article?

From Midnight Crossing" (Air Force Magazine, July, 1999) in comments on possible problems with Russian nuclear reactors:

Even if handled well, loss of power and cooling at the numerous waste pools where atomic fuel rods are kept could cause the water to boil away and permit the release, into the local atmosphere, of lethal levels of radioactivity. Recently loaded rods-those placed in the waste pools within the past two years-could begin to melt down within 48 hours of a loss of power.

-- Tom Carey (, July 09, 1999


I don't know who Robert Wood is, but Robert Cook DID write this in this thread

-- Anita (, July 09, 1999.

Oh boy, I meant to write, Robert Cook, but obviously I didn't!

-- Tom Carey (, July 09, 1999.

LOL. I figured you were thinking about cooking on a wood stove.

-- Anita (, July 09, 1999.

Hmmm. I think this is the difference between a half-empty pot and a half-full one.

Wat was posted about reactors was that after a short cool-down period, all that was needed to keep it safe was to keep the core coolant water topped up. The residual heat is removed by water boiling. Letting it boil dry would leave no cooling and a disaster in the making, but that would require complete long-term dereliction of duty by the reactor operators. If all else failed, water could just be tipped in by the bucketfull.

Much the same would appear to be true for waste storage. I think its just spun differently (anti-nuke rather than pro-) If the 48 hour figure is true, it suggests that the storage pools should be made rather larger (so they'd take longer to boil dry).

You might want to consider a kettle element. Immersed in water, it simply boils. Allow the water to boil away and (if the power cutoff fails) the element will melt down.

I seem to remember that the heat output of a nuke core after 2 days was quoted here as .005% of operational. If the nuke generates 500MW normally, that's 25kW, or about ten UK household kettles.

-- Nigel Arnot (, July 09, 1999.

This is all very interesting....if you understand it. I know I am not the ONLY dummy on this forum. Lets cut to the chase. If a nuke has to be suddenly shut down, is it 4 days or 4 months for cooling.? And will the public even be ALLOWED to know about it??

Taz...whose old brain just gets less wrinkles while the face gets more.

-- Taz (Tassie, July 09, 1999.


What Robert Cook posted has nothing to do with Chernobyl-class reactors.

This thread refers to Russian nuclear reactors, right? So confusing the picture with yada yada about a completely different scenario is just a well-known trolling technique from Anita who speculates that it would go by unnoticed by innocent, uninformed lurkers.

Concerning the NRC decision for US reactors "Y2K-Ready to Crash" we will all have to wait to see how it unfolds when the EPA, the Ralph Naders of this world, and plain constituents jump into the act.

If violation of proven safety regulations and quality assurance protocols prevail, it is just asking for Three Mile Island-type catastrophes to happen. DO NOT COMPLAIN later. As y2k has duly proven, time cannot be rewinded nor post-poned.

Take care and get involved. If you don't care nobody else cares either.

-- George (, July 09, 1999.


You're getting funnier. You wrote: "This thread refers to Russian nuclear reactors, right? So confusing the picture with yada yada about a completely different scenario is just a well-known trolling technique from Anita who speculates that it would go by unnoticed by innocent, uninformed lurkers."

I never even READ the "Midnight" or whatever thread to which the poster referred. He mentioned something about core cooldowns and I remembered having read a thread wherein Robert mentioned it. I simply provided a link to that thread. If it wasn't the one the poster wanted, I don't think I'm to blame for that. You can't blame your bad hair days on me ALL the time, George.

-- Anita (, July 09, 1999.

C'mon kids, settle down.

Anita- thanks for the reference to the lost post from Robert Cook.

Taz has put the question very clearly -- 4 days? 4 months? or what?

George (or anyone!)-- Are fuel rods in a Chernobyl-type reactor hotter than fuel rods in PWR/BWR-type reactor?

The recent NRC report on U.S. reactor compliance indicates that some 35 reactors here are not yet compliant, but the systems enabling safe shutdown are compliant. I read in this the possibility that some of these may shut down if the distribution system has problems. If any of them actually do shut down, the length of time it takes to cool the cores below the danger point is a real question, given other possibilities such as lack of fuel for emergency generators.

-- Tom Carey (, July 09, 1999.

The answers given relate to the usual design practices for a US/UK/Canada/France/Germany/Spain/japanese/Korean reactor and cooling pool/refueling pool design using the "western" design practices.

These require spacers between the fuel assemblies, set the minimum and maximum pool depths, time between refueling and fuel transfer, backup power supplies and emergency generators, backup fuel pool and refueling pool cooling systems, and backup service water systems. These are light-water and heavy water (Canada) systems using thermal nuetrons in a water-moderated, water-cooled reactor with zirconium-clad fuel assemblies.

Under these cases, the calculations stand as written. 3-4 days to cool to room temperature. Decay heat from the core load declining to neglible levels in a few weeks, fuel storage pool able to be cooled by any number of emergency coolers, bypass pumps, or simple water replacement. The specific alternate paths will vary at each facility, but there are usually four designed modes using different emergency generators or alternate on-site power supplies, and another 3-6 alternate (manually configured) modes.

While the nuclear physics involved in radioactive decay of spent fuel is universal, the specific design criteria for a Russian-designed plutonium weapons breeding reactor like Chernobyl is fundamentally and mechanically totally different. I'll look up the design of the Chernobyl reactor building(s) and try to get spent fuel storage drawings, but the part of the drawings released and available so far has been the core and steam generation areas of the plant - not the fuel handling and storage.

(Since these two areas are directly related to plotonium production for the Russian nuclear weapons program, I'm not positive I'll be able to get the actual drwings even then! Ever here of a little group called the KGB?)

Until I see either the Russia load factors in their fuel pools, and the sizes and shapes of the pools themselves, plus the specific Russian graphite-moderated fuel assemblies - I'm not going to make assumptions about what they (the Russians) have done in the past (when they had money) and now, when they are broke and desperate. It may be this bad, they (the writers) may be exaggerating. I know I can't tell you for sure which is true - nor (if true) at many facilities it may be this bad - not all reactors are operated the same way over there.

Let Ted Turner, Al Gore and the Democratic socialists assume the Soviets are the world's environmental heroes and the US is the world's villian - I know the utter distain they have for people's lives, their children's safety, and the safety of anybody who oopses them.

-- Robert A. Cook, PE (Kennesaw, GA) (, July 09, 1999.

Anita, my apologies. No strings attached. I just blew some steam off. Sorry. Still virtual friends?

What happened was that I took for granted Anita that, without necessarily going into the "Midnight Crossing" link, you had still read in the original post that the question revolved about Russian nuclear reactors, not US. Still, it's o.kay, I for one may that sort of mistake every day, more than once. So your input was still good and valid and we all thank you for it. You see Anita, I'm no bully... please no hard feelings.

Now, down to business

Tom, the short answer to your question is "It doesn't matter". Fuel rods in Chernobyl class reactors could be hotter or cooler (give or take a couple of hundred degrees C) than PWR/BWR-type reactors. What DOES matter is the completely different scenario. One thing is the USA, the NRC, bla, bla, and another completely DIFFERENT thing is Russia and Chernobyl 'technology'.

As your own "Midnight Crossing" link clearly leaves on record, Russia today fails miserably in many things that affect the subject matter at hand, be it command and control nuclear structures, decision- making, logistics, scheduling, planning, pirated software/hardware/firmware, half-forgotten program languages, very old computers, failure in telecommunications, in electric power generation, distribution and supply, banking (tens of thousands of nuclear scientists who have not been paid regularly in years!) political and economic upheaval, mafias, disruption of nuclear facilities by thieves, non-performing diesel generator back-ups, etc., etc. So all of these problemas, plus the serious impairment in tracking the reactor's facility's status, make recovery all but impossible. Read it, it's all in your own link. Melt down of loaded rods within 48 hrs. of loss of power is for REAL. Then we have that only 25% of Russian nuclear material is under control. And of course that safe shutdown still means millions will freeze to death.

Anita, Tom, also please read carefully the last 10 paragraphs (they are real short, average of 5 lines each) which tie-in with many other y2k items of debate.

Warm regards

Take care

-- George (, July 09, 1999.

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