That particular work wasn't terribly related to each other -- the
pressure vessel samples are chunks of the reactor vessel material that
are placed in special specimen holders designed into the vessels on
initial installation and then removed after a specified set of intervals
and tested. The primary test for these samples is for ductility
(testing against radiation-induced embrittlement) to, as you inferred
correctly, determine that the vessel and other high pressure components
have not undergone excessive degradation so as to still be capable of
withstanding operating pressures and temperatures.
The accelerometer measurements in piping I referred to earlier were for
the pulverized coal flow distribution pipes in coal-fired boilers, not
nuclear plants. These are fairly low pressure but high air flow volume
pipes and the air is both for coal transport and is also a major
fraction of combustion air. Since it isn't liquid fluid flow and is
blown not pumped, cavitation isn't an issue there. The turbulence noise
here is simply a byproduct of the transport system that we were using w/
the characteristics that fluid transport/flow isn't stochastic but
chaotic to find information regarding coal and air flow rates buried in
that ultrasonic signal we could pick up via the accelerometer. It had
the major advantage of being non-invasive as coal dust is extremely
abrasive so it's a major hassle to try to keep instrumentation alive
that can survive inside a pipe. Being as how there is no free lunch,
the counter problem was that the processing was quite intensive.
Back to your question regarding flow noise and measurements in nuclear
plants -- in general, the answer is "yes, stuff like that is done" and
is done routinely as you're familiar with for preventive maintenance and
other various mechanical systems. If you've worked in the area much at
all you've probably come across my last employer that I mentioned above,
CSI (Computational Systems, Inc) in Knoxville, TN, now a subsidiary of
Emerson Electric in the Rosemount catalog of instrumentation.
As for other similar measurements in reactors, the secondary piping and
so on wasn't particularly my area of expertise. I'll note, however,
though, that other than the reactor itself, the rest of the plant is
really no different than are the other large generation plants in
pressures and/or flow; in fact, super-critical fossil boilers run at
much higher pressures and temperatures than do pressurized water
reactors. The containment of such fluids was pretty much routine long
before commercial nuclear power came along.
There is routine monitoring of primary reactor coolant pumps for such
problems as you would expect. As a complete sidelight, interestingly,
the reason the TMI accident progressed to the point it did was that the
operators misinterpreted some pressure/temperature data and fearing
cavitation in the RCPs turned them off, thus cutting off forced
circulation in the core for several hours. The accident sequence was
brought under control and began to be stabilized when the SRO of the
subsequent shift recognized the issue and had the pumps restarted as
well as the HPI (high pressure injection) system and recovered the core
and reestablished core cooling. If the first crew had simply kept their
hands in their pockets and let the safety systems and control systems
"do their thing" there would have been no event other than a reactor
trip and a manual reset of the PORVs and the plant would have gone back
to normal operation in a week or so after some routine maintenance. A
case where an event can be turned into a major one by a combination of
mistakes after a mechanical failure (which wasn't terribly uncommon nor
is unexpected, particularly, for a PORV to not automatically reclose
which not being manually closed after it failed to reseat and not being
recognized was open was the source of the primary coolant loss).
Some of the things that are unique to nuclear units that are done to
monitor for early signs of failure or mechanical problems in the reactor
include "loose parts monitors" and "neutron noise analysis". The first
of these uses a group of accelerometers mounted in various places on the
reactor vessel and primary coolant piping and "listen" for impact noises
that could be the result of some reactor internals failure or similar.
They are tied into systems that use a triangulation method on time of
arrival for impacts to try to localize where within the plant any
particular noise might actually be coming from. Did do the software for
a prototype one of these systems for TVA way back when, too...just after
the REMOTEC work. Unfortunately, then was about the time TVA was
pulling back so only the one prototype was ever finished and by the time
things picked up again, technology (and I) had moved on...
"Neutron noise" is a very interesting and intellectually and
computationally challenging area -- it uses the small fluctuations in
the signal of the excore neutron detectors and signal processing to
infer things about reactor internals such as the movement of the core
inner liner or fuel assembly vibrations. As the inner barrel moves
slightly (on order of tens of mils), the change in water density owing
the that slight change in thickness is discernible in a very small
fluctuation in the neutron flux at the detector. By monitoring this in
time, if something were to happen to one of the studs that holds the
barrel in place, one could detect a larger amplitude of barrel motion
(this has happened at at least on reactor I'm aware of). By knowing
this before either the next outage or larger damage became apparent, one
can monitor the situation and determine when or if an early shutdown
would be required.
There are any number of other monitoring systems and instrumentation
besides for almost all systems and certainly for those that are directly
Again, undoubtedly, far more than one might care about in ahr... :)
I think I understand about the pulverized coal. Ultrasonic transducers
are used to measure the flow of material through the pipes because a
paddle wheel would quickly disintegrate? Rereading what you wrote it
seems that you were listening for a specific resonance or you were
trying to separate the sound of the airflow from the noise of the flow
of the pulverized coal mixed with it. Is that what all the processing
power is required for? It kind of reminds me of what modern military
sonar systems do. Heck, I find everything interesting, back in the last
century BI, "Before Internet", I spent a lot of time in libraries
reading every sort of engineering, scientific or medical journal I could
get my hands on. Years ago, there was a Star Trek convention in
Huntsville, Alabama hosted by NASA engineers and instead of looking for
Mr. Spock, I was hanging out with the engineers looking at and
discussing all the neat stuff they had on display like cross sections of
the Space Shuttle fuel tank showing the different layers in its
construction. Don't worry about the subject matter, I find it all
interesting, besides, it will make me go searching The Web for more
Anything like a paddle wheel wouldn't make it 5 minutes. :)
In an early stage of the work, I tried a hardened steel drill rod as a
sounding rod in one small-scale test facility. The test duration was
only for a couple of days and it came out oval in cross-section in even
that short a time frame with a good third of the frontal surface gone.
The utilities are very reluctant to insert stuff into the coal pipes
that could fail and either block the flow in a pipe w/ a resultant high
pressure event back at the pulverizer or block a burner nozzle in the
furnace and cause an event there. The air:fuel mixture is right at the
limits and so it's a real danger of fire or explosion if something goes
wrong outside the boiler or in a coal pipe. Needless to say, an open
14" pipe w/ a burn out isn't a desirable event... :) In at least few
cases where they have happened the flame has actually melted the side of
a boiler containment and ended up w/ an entire boiler open. That wreaks
havoc in a plant _very_ quickly. :(
As far as more explanation of exactly what the computations are,
unfortunately, the actual technique is proprietary but it does not look
at the signal in a conventional sense at all; it is not, as I've stated,
based on frequency components per se, but on the fact that turbulent
flow is chaotic, not random. It doesn't repeat exactly, but there are
certain patterns and we have identified some 30 scale-invariant measures
that can be calculated from the broadband ultrasonic signal as picked up
by a passive accelerometer as minute vibrations transmitted through the
pipe wall. We do not introduce any additional energy into the pipe at
all as does a classic ultrasonic detector.
There were some other research teams looking at other techniques such as
microwave and/or more approximating conventional ultrasonics but our
technique was/is unique.
In other words your sensors were passive listening devices not active
like the ultrasonic flow sensors I'm familiar with? I'm guessing you
were looking for a semblance of a pattern in the white noise of the
chaos. Am I getting warmer? :-)
Yes, as I said they were/are simply high frequency (>75 kHz resonance)
commercially available accelerometers...
Except white noise implies a stochastic process whereas a chaotic
process, while not strictly repeatable, is not stochastic. Hence,
typical statistical measures used for such processes are not effective
and the measures used in the analysis are, as mentioned, nonlinear and
then combined in other nonlinear ways for prediction. (I know, that's a
lot of mumbo-jumbo unless one already knows the answer, but as I say,
the specifics are proprietary so can't really reveal much more about the
Suffice it to say that there is information buried in the audible and
supersonic noise of the flow and that can be related to the actual air
and coal flow rates in a given pipe over a range of operating conditions
and air:fuel ratios and flow rates by a set of specific operations on
the recorded waveform. One important feature of these computations is
that they all produce quantities that are independent of the actual
magnitude of the signal itself (iow, they're self-normalizing). This is
a key feature in that it means that simply a level change from a
location difference doesn't affect a given signature. It also means, of
course, that simple measures such as the mean aren't what is giving the
actual correlations. :) But, from those correlations a prediction of
flow is possible for a given new set of measures computed for the same
pipe from any set of operating conditions and this has been shown to be
valid over a range of operating conditions and at various power plants
of differing sizes and styles and manufacturer (albeit the correlations
are at least to this point plant-specific, the measures used in those
are for the most part the same ones of of the total set of those
identified as candidates).
The only problem I'm having is grokking the difference between
stochastic and chaotic. I suppose there must be a enough difference
between random and disorderly for your system to work. I love this kind
of stuff. :-)
Indeed, there is a fundamental difference.
The beginning of the following link is on the line of the way I used to
try present it to the bleary-eyed utility guys who really only wanted to
know enough as to whether they thought it (the R&D project; EPRI is a
utility self-funded research organization so we had to have buy-in from
the member utilities to continue to have the resources to support the
effort) made enough sense to continue or not and like you, wanted at
least a grasp of the concept.
I'd not read the Wikipedia entry on chaos; so often they're not of much
help so did--it's not terrible reading.
For a non-technical read if you're interested in such things, I'd recommend
_Chaos: Making a New Science_ by James Gleick
It's the best written of several of the popular expositions imo for a
general overview of chaotic systems in natural processes.
For more esoteric approach, Benoit Mandelbrot is a stretch but two of
his at least summarized rather than actual papers include
Of course, there's an almost unlimited literature on turbulent flow but
other than how it's touched upon in some of the above as a field I don't
know of any popularization of the subject itself. The pneumatic
transport of solids is, of course, a subset within it with another whole
None of those will explain the processing we're doing; but they are an
interesting introduction into a whole (relatively) new way of looking at
much of the physical world.
But the validity of the processing inherently requires that the
underlying process be chaotic, not stochastic; it (the method) is simply
a way of making approximating functions that are indirectly related to
things like the Lyapanov numbers, etc., that can be measured and
computed in sufficient quantity and speed to be the basis of an instrument.
It is indeed a fascinating field w/ almost as many bizarre features as
string theory and higher dimensions.
Well, thanks for nothing. At the New Years party last night I was
discussing that with a couple of ladies and I promised to get back to them
with some reports. My chances of getting laid just went down now thanks for
you. They were really excited too when I talked about differing containment
A lot of the programs the major insurance companies run on -
particularly the actuarial stuff in the life insurance business is
STILL Fortran. Same programs developped in the '60s, still running
with modification after modification.
On Thu, 30 Dec 2010 19:47:49 -0500, firstname.lastname@example.org wrote:
Maybe so. But I spent years at Allstate and CNA insurance and knew
State Farm and Farmers Group employees and talked shop with them.
Those are major insurance companies.
It was 90% COBOL and assembler.
That covers a gamut of the usual insurance company processing, and I
worked in the major insurance processing areas - premiums, claims,
accounting, investments. Did payroll elsewhere, all COBOL.
Never saw a Fortran app anywhere, and I got around to most areas.
Doubt there was any tucked away either, unless somebody was running
Fortran from a PC.
I had access to the system libraries and would have seen it.
Pretty much knew all the programming tools where I worked.
Might have been tucked away somewhere.
I never say never.
And though casualty isn't life, most insurance processing is as i
You run into "scientist" users who prefer a language, but they are a
small part of business processing. I had a client at McDonalds
corporate marketing who liked using SAS for some day-part analysis.
He got no help from me.
Marketing staff there were still using Macs and they got just a little
help. But that's not why I was there.
McDonalds actually did analysis on what was sold at different hours of
the day. Massive amounts of data coming in from POS terminals.
First time I heard the term "terrabyte" but I left before they got the
IBM drives in. Boucoup expensive.
Now anybody can get multiple terrabytes cheap at Best Buy.
Reminds me of the data management boss there.
First day there I grabbed maybe 100 cylinders of disk to run
something. That was no big deal in my previous shop, and about the
same bytes as what I had on my big PC hard drive at home.
I get a call from data management a few minutes later asking what's
up. I told them what's up, and that was that. They asked me to call
first next time I want that much space.
Later that day I'm out front for a smoke and I get introduced to the
data management boss.
"Vic? Rings a bell. You the guy who hammered my space?"
"C'mon," I said. I got that much on my PC hard drive at home.
"Bring it in." he says.
Not much for words, but I liked him and we got along fine.
Closest to actuarial I got was working for an epidemiologist at
International Mineral and Chemical.
Similar mortality study to actuary I think.
He loved me, because I built a huge table and report process for him
for a study he was doing. Used COBOL.
At that time COBOL - ANSI 74 I think - had a 32k max for indexed table
size. I needed to store and access about a dozen times that.
About 18,000 deceased employee vitals, work site and job position.
Mostly Florida phosphate workers.
I started a Rube Goldberg of multiple tables to handle it, mentioned
my predicament it to an "old-timer" who was really sharp, and he
showed me how to trick COBOL by defining filler area beyond the
allowed table size in working storage and subscripting into it.
Slower than the binary search on the search end, but it ran fine.
Never met another programmer who knew that one.
It was a good start to my IT first job, and I won't forget Mike.
Lots of ggod guys I learned from, and I tried to pass it all on.
God dammit! Gimme another beer and a hanky!
That's not exactly what I said, it was that a ME professor who assigned
a program in Fortran for homework, and was incredulous that nobody could
complete it. Still a sign of a disconnect with reality IMHO :)
replace "roosters" with "cox" to reply.
COBOL "still used"?
There are more lines of COBOL code in production than any other language.
Most financial back-room stuff is in COBOL. For example, almost the entire
Social Security System EDP is in COBOL. There are many production programs,
written back in the 60's, that are still running in production every day.
These examples may say more about the unchangeability of the financial
system than the COBOL language, but they're interesting nevertheless.
On Thu, 30 Dec 2010 19:14:03 -0600, email@example.com wrote:
both are "viable" If you are not looking for a lifetime job guarantee.
Civil engineering is harder than some jobs to send off-shore, and
EVENTUALLY there will need to be electrical engineering done in north
america. Might be a good idea to studi Punjabi , Sanskrit, Mandarin,
and a few other eastern languages along with the engineeing if you
expect to be very valuable in the future though.
On Thu, 30 Dec 2010 19:14:03 -0600, firstname.lastname@example.org wrote:
There is nothing wrong with either but don't expect any guarantees. Don't go
deep into debt to get the paper.
I'm an EE and have had no problem finding a job, but I have a lot of
experience and history. I'm sure it would be a lot more difficult to break in
now, even though the mid-'70s were no picnic either. I did get in at the tail
end of the "lifetime employment" era. As Clare says, don't expect anything of
the kind, but there are also some amazing opportunities for the right sort of
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