Et vu cette réalité, on a froid dans le dos et prend peur encore plus des miracles nucléaires qui se produisent sans cesse, à voir la liste infinie :
http://old.disinfo.com/archive/pages/ar ... index.html
http://en.wikipedia.org/wiki/Everything ... w_Is_Wrong
et une armada en vidéos sur ce sujet :
en plus c'est une histoire vraie :
Power Plant Porno
Pornography may or may not have social value, but a skin magazine may have damaged important equipment at a California nuclear plant in March 1984:
A misplaced magazine was sucked into a crucial cooling water system at Diablo Canyon Nuclear Power Plant, breaking a giant pump, a Pacific Gas and Electric Co. spokesman said yesterday. A plant worker apparently set the magazine too close to a pipe that sucks in air to cool the pump engine, said startup engineer John Sumner. Sumner said it was rumored the offending magazine may have been a forbidden "girlie" publication that a plant worker hastily stashed near the air intake. [13]
The NRC should not adopt regulations protecting nuclear power plant equipment from pornography. If it did, testing and inspections would be required to verify that the regulations were being satisfied.
Nuclear plant owners essentially banned pornography in the late 1980s when they placed restrictions on non-technical materials in the workplace. The "nudie" magazines were replaced with "nukie" magazines.
Mystery Plug
On Saturday night, June 28, 1980, operators reduced power at Browns Ferry Unit 3 in Alabama for a scheduled maintenance outage. Tradition called for the plant to be manually tripped when power dropped to about 30 percent. An operator depressed the trip pushbuttons, and control rods raced into the reactor core. But not all of them--76 of the 92 control rods on half of the core were not fully inserted. In fact, many of these control rods had hardly moved in at all. The reactor was still running.
About two minutes later, the operator depressed the trip pushbuttons again. This time, 59 of the stubborn rods remained withdrawn. The operator depressed the pushbuttons again. There were still 47 control rods withdrawn.
The third time may be a charm, but it was the fourth time at Browns Ferry that night. When the operator depressed the pushbuttons a fourth time, all of the control rods fully inserted. It had taken four tries and about fifteen minutes to shut down the Unit 3 reactor.
No one knows what happened that night. The theory is that something plugged one of the scram discharge headers. The fourth scram attempt allegedly dislodged this mystery plug and blew it into the reactor building's sump, where it hid amid considerable other gunk and grime. [11]
Safety in Numbers?
What are the chances of a nuclear accident? Here's what the NRC said in 1984:
"The most complete and recent probabilistic risk assessments suggest core-melt frequencies in the range of 10-3 [one in one thousand] per reactor year to 10-4 [one in ten thousand] per reactor year. A typical value is 3x10-4 [three in ten thousand]. Were this the industry average, then in a population of 100 reactors operating over a period of 20 years, the crude cumulative probability of [a severe core melt] accident would be 45 percent."
Hence, the Nuclear Regulatory Commission reported about a 50-50 chance of a core meltdown occurring by 2004. Time is running out!
Asleep at the Switches
On March 24, 1987, the NRC heard from a whistleblower that operators at the Peach Bottom plant were sleeping on duty in the control room. The NRC immediately sent inspectors out to the Pennsylvania facility to investigate. The inspectors reported:
"At times during various shifts, in particular the 11:00 PM to 7:00 AM shift, one or more of the Peach Bottom operations control room staff (including licensed operators, senior licensed operators and shift supervision) have for at least the past five months periodically slept or have been otherwise inattentive to licensed duties." [14]
During a midnight shift, NRC inspectors found all three operators asleep and the shift supervisor reading a magazine. On another shift, the shift superintendent, the shift supervisor, and two operators were asleep while the remaining operator was awake, but he was not in the control room. Finally, the NRC inspectors found the operators on another shift gathered around a console playing a computer game. [15]
Although sleeping operators make fewer mistakes than awake operators, the NRC still became disenchanted. They ordered Peach Bottom shut down.
A spokesman for the nuclear industry's trade group explained why operators sleep on duty: "The problem is that's its an extremely boring job." [16]
Before a gathering of local townspeople, an NRC staffer complimented the Peach Bottom operators: "If they are awake, they can do the job very well." [17] Glowing praise, indeed.
The two units at Peach Bottom remained closed for over two years. Then, with a brand new management team--and very well-rested operators--the plant owner restarted the reactors.
How Have I Failed Thee? Let Me Count the Ways, Again
Thursday April 7, 1994, began with both units at the Salem Generating Station in southern New Jersey operating at about 75 percent power. Operators had reduced power in case one of the circulating water (CW) pumps tripped. Five of the six CW pumps for each unit were running, with the sixth pump in standby. These pumps take water from the Delaware River, send it through the condenser to cool the steam leaving the turbine, then discharge it back to the river. Since the beginning of March, dead reeds and marsh grass floating on the tides had clogged the debris screens for the CW pumps several times each day. This was more than inconvenience--cooling water from the bay was needed to remove heat from the reactor core.
At 10:14 AM, debris began accumulating on the screens. Within ten minutes, two of the five operating CW pumps automatically tripped on high differential pressure across the debris screens (failures #1 and #2). An attempt to start the standby CW pump failed because its breaker had been improperly positioned after maintenance (failure #3).
By 10:30, operators were reducing power by injecting boric acid and inserting control rods. They rushed to get power down to the point where three circulating water pumps could handle the heat load.
At 10:36, an operator restarted one CW water pump. The pump's discharge valve, which had to be closed to restart the pump, began slowly re-opening.
At 10:39, two other CW pumps automatically tripped because of high differential pressure (failures #4 and #5). One other CW pump was restarted.
At 10:40, the plant's power level had been reduced to 57 percent. Although three CW pumps were running, only one was actually providing cooling water flow to the main condenser, since the discharge valves for the two other running CW pumps were still opening.
At 10:44, the power level was 24 percent. Three CW pumps were running, until another CW pump tripped because of high differential pressure (failure #6).
A minute later, with power down to 18 percent, an operator left the reactor controls to transfer electrical loads in the plant (failure #7).
At 10:46, power had dropped to 8 percent. The reactor coolant system temperature was too low, so a supervisor stepped to the reactor controls and withdrew control rods to bring it back up (failure #8). Another operator restarted a CW pump while another CW pump tripped again (failure #9).
At 10:47, reactor power was about 7 percent. The reactor coolant system temperature was below legal limits (failure #10). The supervisor stepped back from the reactor controls and directed an operator to restore the temperature to the legal range.
The operator withdrew control rods for 55 seconds to increase the plant's power level (failure #11). At 10:50, the reactor automatically scrammed because of high neutron flux at 25 percent power (failure #12).
By 11:19 AM, the pressurizer had completely filled with water, and its power-operated relief valve (PORV) was opening periodically to relieve the rising pressure (failure #13). The atmospheric dump valves (ADVs) should have opened to control pressure on the secondary side, but they failed due to a longstanding problem (failures #14 and #15).
At 11:26, all four main steam line safety relief valves opened to protect the secondary side from overpressurization. Operators tried but failed to reset the ADVs so they would automatically open (failure #16). The operators manually opened the ADVs to reclose the safety relief valves.
The open ADVs caused the pressure on the primary side to drop rapidly. The decreasing pressure resulted in another safety injection signal (failure #17). The safety injection flow increased primary side pressure until the PORV began cycling again (failure #18). The PORV discharged steam and water to the pressurizer relief tank until it overfilled (failure #19) and spilled contaminated water into containment.
Operators realized that primary side was water solid and secondary side pressure was being loosely controlled by the open ADVs. They were in a situation not even close to being covered by their procedures. They allowed the PORV to open and close for the next 20 minutes (failure #20).
At 3:11 PM, operators restored a steam bubble in the pressurizer. They were back in a condition covered by their procedures. A "routine" plant shutdown using normal procedures followed. [19]
The NRC was less than pleased by this event. They fined the plant's owners $600,000. [20] That's $30,000 per error. Since the NRC was allowed to assess penalties of $50,000 for each day of each violation, Salem's owners must have received the volume discount.
"Two wrongs don't make a right" is an old clich�. The folks at Salem tried to figure out just how many wrongs it does take to make a right.
Not So Slick
The Big Rock Point plant near Charlevoix, Michigan, shut down permanently in August 1997 after nearly 35 years of operation. A year later, as the plant was being decommissioned, workers couldn't empty the sodium pentaborate tank in the standby liquid control (SLC) system. They found the pipe that carried the sodium pentaborate solution to the reactor vessel was completely severed. They concluded that for at least the last 13 years of the plant's operation, this safety system would not have functioned had there been an accident. [21]
The acronym SLC is pronounced 'slick' within the industry. In this case, it was actually not so slick.
Wrong Place, Wrong Time
The following events demonstrate the value of the adage, "If it ain't broke, don't break it!"
On April 22, 1982, an operator drained reactor water from Point Beach Unit 1 in Wisconsin. Problem was, he had been assigned to perform this activity on Unit 2, which was shut down at the time. Unit 1 was operating and had an urgent need for all of its reactor coolant.
One June 17, 1970, an operator at the LaCrosse nuclear plant near Genoa, Wisconsin, used a dust cloth to clean the control room. The cloth snagged the identification tag attached to one of the key switches and moved it around to the OFF position. The repositioning of this single switch caused the reactor to automatically shut down.
To prevent this unfortunate event from happening again, the control room operators were instructed to use a feather duster when cleaning
The training program for operators consists of more than a year's worth of classroom instruction and simulator exercises. The proper techniques for feather-dusting are not covered during this otherwise comprehensive training.
Aerial Disaster
In January 1971, an Air Force B 52 bomber crashed about 20 seconds short of the Big Rock Point nuclear plant in Michigan. All nine crew members on board the plane died in the crash. The plane had been on a routine training mission. [25] The Air Force (luckily, ours) conducted low altitude simulated bombing runs near the plant for years.
This Picture's Worth A Thousand Cuss Words
On the morning of August 7, 1997, an instructor at the Haddam Neck plant in Connecticut took a picture inside the fire detection panel in the control room. The camera used its flash to light up the darkened interior of the cabinet. An alarm sounded. Three to five seconds later, the fire suppression system discharged Halon into the control room from overhead nozzles. The Halon gas, which functions like carbon dioxide to extinguish fires by displacing oxygen, blew into the control room, scattering papers and dislodging ceiling tiles. A falling ceiling tile struck, but did not seriously injure, an operator on his way out of the room. Within 30 seconds, the control room was abandoned.
After the operators left the control room, they assembled in an adjacent room where they could monitor the control panels through a window. When an alarm light blinked on and off, an operator would rush back into the control room, without self contained breathing apparatus, and respond to it. About 35 minutes later, the ventilation system had removed enough of the Halon gas to allow operators back into the control room.
Subsequent investigation determined that the flash from the camera affected a microprocessor in the initiation circuit for the Halon system. The fire suppression system was supposed to have a one-minute delay between warning alarms and Halon discharge to enable workers to safely exit the area, but the flash caused a premature discharge. It happens. Or so they say.
To prevent future occurrences, the plant's owners posted signs on all fire system control panels warning folks that photography is prohibited inside the cabinets. [26]
It's been said that a picture is worth a thousand words. In this case, the majority of them were probably expletives.
On January 31, 1994, workers at Tricastin Unit 1 in France were removing the control rod cluster guide tube from a spent fuel assembly. A 15-foot-long screwdriver weighing 44 pounds fell into the spent fuel pool and punctured the stainless steel liner. Level in the spent fuel pool dropped nearly four inches. A stainless steel plate was welded over the hole.
Luckiest Men in Tennessee
On April 19, 1984, eight workers entered the seal table room at the Sequoyah Unit 1 facility in Tennessee to clean the incore probe thimble guide tubes.
The incore probe is a neutron detector on the end of a long, flexible cable that is normally stored outside the reactor core. Periodically, the probe is inserted through a number of thimble guide tubes located within the reactor core to determine the power distribution.
The workers disconnected the thimble tubes and inserted a cleaning brush. While the brush was being hand-cranked up one of the thimble tubes, workers noticed water leaking around the fitting holding the guide tube.
The eight workers immediately evacuated the seal table room. Seconds later, the fitting broke loose, ejecting the entire thimble guide tube and cleaning assembly from the reactor core. An unisolatable reactor coolant leak ensued. The hot reactor water flashed to steam as it shot into the room. The leakage, initially about 30 gallons per minute, continued for approximately eleven hours until the reactor was shut down and the reactor water level was reduced to below the seal table. Approximately 16,000 gallons of reactor coolant leaked into the containment during this period.
Radiation surveys conducted the following day indicated two to three rem per hour at the entrance to the seal table room, 200 to 300 rem at the end of the thimble tube near the seal table and greater than 1,000 rem in the center of the ejected tube. The tip of the thimble tube was reading approximately 4,000 rem. [27] A lethal radiation dose is 450 to 600 rem.
The investigation of this incident revealed how close it came to being a disaster. While the workers were inside the seal table room, another group of workers arrived to perform maintenance on an airlock door, which happened to be the outer door on the airlock into the seal table room. They disabled the outer door for nearly 30 minutes while doing some welding. With the outer airlock door disabled in the open position, the inner door was interlocked closed. The workers inside the room wouldn't have been able to leave the room quickly during this time. The steam conditions and the radiation levels inside the room would have threatened their lives.
When the workers got into the airlock, one of the workers picked up the telephone to inform the control room operators about the leaking reactor water. The phone line was dead.
etc.....
Obamot va traduire, les verbes ne sont pas à la fin des phrases !!!
