RBMK is bad. It is very, very BAD.

[Kerembaev@cs.com]

Doug and others,

I thank y'all for a very good educational information.
For the sake of pluralism of opinions, I just would like to add my ten cents

There never was a question that compare to RBMK the vessels reactors are 
smaller, safer and easier to operate, this is why, they are used on the 
ships, on the first place.
RBMK is not the only graphite moderated reactor. Graphite moderated reactors 
in the FSU as well as in the US (and may be also in GB) were designed and had 
being operated for WP production (so much sweat and blood and now it is 
burning in CANDU, why not to build Breeders again???).
RBMK-1000 is cheap and easy to build, particularly if there is no sufficient 
large vessel reactor production capability. Dr. Minnema is right, there were 
problems with MASS LINE PRODUCTION of the large reactor vessels (1000 and 
1500 electrical megawatts plants) in FSU and because of planning and 
expending economy (poor energy efficient technologies) RBMK-1000 and 1200s 
were build for big power NPPs. Y'all probably heard the story that we had 
planned everything.........

I am not a RBMK supporter.
While I was in school, I did a few RBMK-1000 and RBMK-2400 calculation and 
design projects and we knew all those RBMKs bad features; positive temp. 
coeff., instability on low reactor power levels, lack of a strong 
containment. All that, what in a some or the other way led to the explosion 
and determined magnitude of the fall out. But if you read and analyzed the 
aftermath accident report, it is always boring with many details document, 
you could see that after all those SOP violations, a senior reactor 
engineer-operator (he and I went in the same school) manually activated the 
emergency reactor shut down system # 2 (AZ # 2). Normally it supposed to be a 
remedy but in those reactor conditions it was a TRIGGER because of the 
emergency rods tips design; tips hollowness which caused decrease of the 
neutron absorbent amount in the active zone at the first moment by pushing 
out the water: coolant-absorbent-moderator. 
The flaw of the emergency rods tip design NEVER had being addressed before 
the accident. 
If the operator (he died from rad. burns 29 days after the accident, with the 
last words WHY THESE HAPPENED??? Not understanding HOW??? Or disbelieving 
WHAT???) did NOT activated the system there would be at maximum, the 'maximum 
projected accident" - rupture of "the first contour", of course the term 
"first" here is a conditional because the plant has no physical separation 
between first and second contours. For this case the plant has an emergency 
system which did handle these type of the accidents before properly.
RBMK-2400 with a unique maneuverability would be more efficient, easier to 
operate and safer (or in the opposite order) and the same magnitude accident 
would not happen, at least, because of higher U-235 fuel enrichment. But in 
the idea is the same as 1000 reactor with similar flaws.
Not to take it personally, some of the present days opinions are sounded like 
Monday morning coaching. Although there were very powerful RBMK lobby among 
designers.

I never liked RBMKs and I had expressed my opinion on many issues when I felt 
that I had to. Well, you can call it "a bad luck" or a coincidence, after 
school I had to work on RBMK-1000 the next to the exploded one and to provide 
a some systems maintenance on exploded one and it is true that working on 
RBMKs, compare to vessel reactors, is a nightmare.
Because of that seldom a senior reactor engineer-operator lasted longer then 
two years.
There is no reason kick underdogs, most of them now are dead anyway.

I hope, we won't have the same discussion about a some vessel reactor in the 
future.
Public of course wants to hear "NEVER AGAIN" but for a technical person to 
say "NEVER" would be close to the deception. I think, public needs to face 
the fear and we have to give the information in a CONSUMABLE form to help 
public to overcome its radio phobia. It is better to say never for now but 
what if..... and then what???
A small additional point.
There is NO more a cold war for a very, very long time, so some people need 
to get out of tranches and go home.

I guess after all, I am the one who took it personally.
Best Regards and Happy Wednesday to everyone. :-)

Emil.
kerembaev@cs.com




In a message dated 1/18/00 10:15:38 Pacific Standard Time, 
Douglas.Minnema@ns.doe.gov writes:

<< 
 2.  With regards to RBMKs, when Chernobyl exploded I was working at Sandia
 National Labs and was privy to several discussions.  The story I received
 was that the Former Soviet Union was limited in manufacturing capability for
 large pressure vessels.  They could either build submarines or pressure
 vessels for reactors, but not both.  The RBMK was 'convenient' in that,
 while it was a plumber's nightmare, it did not require the pressure vessel.
 While it could be used to produce weapons grade plutonium, most of them were
 not used that way, but only for power production.  If I recall, the
 weaknesses of the design were known, but failures such as Chernobyl were
 discounted by the FSR.
  >>
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