Class 800 pantograph operation

[coppercapped]

Many thanks for your explanation.
I read "light current electrical engineering" and missed the exciting stuff, but my supervisions were held next to the prototype of the world's first commercial scanning electron microscope.

I read physics and spent the first 20 years of my professional life generating, measuring and using vacua...!

 

[bspahh]

John de Armond http://www.johndearmond.com/ posted this on Usenet back in the 1990s.

Redirecting to Google Groups

This story involves TRULY internal combustion propulsion - as in internal
to the atom.

The setting is the Sequoyah Nuclear Plant in Chattanooga, TN. The date is
about 1979 or 80 and we're starting that sucker up for the first time.

I was the shift test engineer, running the startup test program on the evening
shift. Most testing is conducted from the control room. In order
to get to the control room, a stroll across the turbine deck is necessary.
This deck contains the huge (1200 MWe) turbines and a variety of support
equipment. The floor is tiled and the 10 story tall walls are slightly
tinted glass. A glorious sight when bathed in the afternoon sun.

As I was strolling toward the control room, I noticed an Aux. Operator
standing near a device called a moisture separator/reheater. This device is a
large heat exchanger, about 40 feet long and 20 feet in diameter. Its
purpose is to reheat the steam exhausting from the high pressure turbine
in order to dry it before being introducted into the low pressure turbines.
On top of this device is a large safety relief valve with a tailpipe
that extended almost 10 floors through the roof. When this valve opens,
steam at about 900 psi exhausts to atmosphere through this ~36" tailpipe.
The tailpipe is hung from spring hangers and simply floats on the exhaust
flange of the safety valve which allows the pipe to move under
thermal expansion.

Anyway, this operator was standing along side the reheater. In one hand
was a walkie-talkie and in the other hand was a lanyard that ran to the
manual trip lever on one of the safeties. This was not unusual, as the
functionality of these critical valves is tested fairly often. Normally
when the valve trips, there is some steam escaping around the valve, a
loud shreik and a large steam cloud on the roof.

As I was almost to the control room, the operator got some activity on
the handi-talkie and pulled the manual trip lanyard. The noise
from the H-T had gotten my attention and I looked around just in time
for the valve opening. FOOOMsssss!!!! The whole damn tailpipe jumped
up about 6 inches in the air before settling back down.

Since this behavior was quite abnormal, I asked the operator what was
going on. He pointed to the elevator and suggested I go to the roof
to find out. I rode the elevator 5 floors and hoofed it up 5 flights
of stairs and onto the roof. I noticed about 10 guys standing around
near the tailpipe.

As I stepped out, I saw about 6 guys hoisting A 55 GALLON DRUM up and over
the tailpipe. Whoosh. It hit bottom 10 floors below.

A message on the handi-talkie and BOOOMssss!!!!!!!! That damn 55 gallon
drum full of 600 pounds of water had been launched literally out of sight
by 900 psi of steam.

It stayed out of sight a good 30 seconds before it came into view again,
hurtling down over the Chickamauga lake. When it hit the lake, it looked
like a depth charge going off.

I did a 180 degree twist and headed back down the stairs as fast as my
little feet would carry me. As Shultz on Hogan's heros used to say,
"I saw notsing.. I hear notsing.. I know notsing..". I did keep
a piece of strip chart recording that showed the dip in steam pressure
that documents the launch

I heard a few days later that one of their ICBD (Inter County Ballistic
Drums) had been caught by a gust of wind and had come down on a car in
the parking lot, thus ending the era of the nuclear powered missile.
The funny thing is, no one would ever admit to knowing how that drum
ended up on the car, which ended up about 6 inches tall

So if anyone asks if America has ever launched a nuclear powered
missile, you can answer truthful YES!

[BTW, I've waited 10 years to tell this story to ensure that my
memory of the names of those involved has thoroughly faded just in
case the nuke police were to get interested.]


John
--
John De Armond, WD4OQC | The Fano Factor -
Radiation Systems, Inc. Atlanta, GA | Where Theory meets Reality.
emory!rsiatl!jgd **I am the NRA** |

 

[Crossover]

Very interesting thread - thanks for all the replies about the technicalities of the VCB

As an aside, on the subject of the OP, the breakers on 350’s and (from what I remember - it’s been a while since I went on one) Pendolinos are quite noticeable. On the former, the usual telltale is stony silence as the air con drops out!

 

[gsnedders]

Very interesting thread - thanks for all the replies about the technicalities of the VCB

As an aside, on the subject of the OP, the breakers on 350’s and (from what I remember - it’s been a while since I went on one) Pendolinos are quite noticeable. On the former, the usual telltale is stony silence as the air con drops out!

They're very noticable if you're in the transformer pantograph coaches on Pendolinos especially in combination with the sheer silence with the AC off after; I've often enough ended up explaining what makes the banging noise to other passengers!

 

[supervc-10]

@bspahh that story is wonderful, thank you for sharing!