I’ve tried to find online a site that will explain step by step what happened, in that scene and what Jack was afraid would happen during another SCRAM and what happened at the end of the film? But I’ve been unsuccesful. Can someone help?
What I do get:
A turbine stops (I think) so a SCRAM is ordered. ( i dont get what the vibration he’s afraid of is) A faulty gauge tells them the water level is too high, and i think by dumping water Jack exacerbates the problem or creates one by dumping all the water. Nearly causing a China Syndrome.
I don’t get why he can’t get water, or what he does to get water when he turns some switches (Wilford yells at him) and the plant vibrates. I also don’t get what happens at the end of the film when all hell breaks loose.
I’ve never seen The China Syndrome (and your description isn’t incredibly helpful) but I’m willing to bet that the technical details are gibberish made up from whole cloth and only accidentally intersect with any real engineering or physics of nuclear reactors
The vibration he feels is real indeed, it was the feed pump (cooling water) shaking. He fears that if they rely on that pump, and it does have a serious problem, it will leave them without a way to cool the reactor. In the end, it fails but apparently they are far enough along that its failure does not matter, i.e., the control rods are inserted and heating has abated. The plant will require an extensive shutdown to replace the pump.
The water collects the heat from the reaction (“cools” the reactor), feeding the heat to the steam-driven turbine which in turn makes electricity. A certain very high mass of water is required to accomplish this. Too much water/heat and the steam would be too much and damage the turbine.
A faulty indicator leads them to believe the water level is too high, creating too much pressure. So they drop the level, then drop it again. Another indicator informs them that it’s actually too low, and a “technical tap” to the faulty one confirms this. So now heat is building up and the water flow rate may be too slow in replacing the water to cool it before important stuff starts to melt.
If that happened, the more one substance melted into the other, the hotter and faster the reaction would go and the more it would melt whatever was underneath it. [This where the movie physics really digs in. For what would really happen google “Three Mile Island” and “Chernobyl.”] The “China Syndrome” fear is that it will all melt down and start melting its way to the core of the Earth, then on through to China. Possibly even causing a chain reaction that would turn the Earth into a small star.
As I recall, the concern with a “China Syndrome” event was that a total core meltdown might burn its way through the containment vessel. The core would be a large mass of molten metal, and might keep melting downwards until it hit the local water table. At which point there’d be a steam explosion spraying radioactive material widely. That would be a Really Bad Day. Nuclear plants are often located near rivers or large bodies of water, to have easy access for cooling media. For example, the TMI plant is on an island in the middle of the Susquehanna River. The local water table would not be too far.
How far would a fully melted nuclear reactor core get? I don’t know. Containment is some feet of steel-reinforced concrete, but we’re talking about a scenario far from the design specs. A really, Really, REALLY bad day.
The term trip generally refers to a circuit breaker trip. In the case of a power plant, the turbine is a steam turbine or a gas turbine. China Syndrome was a steam turbine driven by a nuclear reactor. The reactor controls consist of many process transmitters. level, temperature, flow, etc. A typical liquid level process will consist of one analog transmitter and 4 switches. a “LOW”, “HIGH”, “LOW LOW” and “HIGH HIGH”. In nuclear power there is most likely a redundant analog transmitter or a way to calculate the level from other transmitters. They determined that there was a discrepancy between two analog process indicators. As they lowered the level based on the reading of one of these indicators, a level switch was activated and triggered an alarm. Those brightly illuminated alarm panels are called “Panalarms”. That was a brand name. Back to the turbine trip. The steam turbine is massive and expensive. It is shaft coupled to a generator, equally massive and expensive. It is very important to remove the generator from the grid if a problem occurs. The generator is exporting power to the grid and will import power if the steam turbine is throttled back. It will freewheel or windmill as it is called. It will turn into a motor. Not necessarily that bad(depends on some things). If the generator is disconnected from the grid(Breaker trip) and steam remains applied to the turbine, it could over speed. Really bad!. So, when certain process indicators reveal a problem, the operators or the automated system will open the breaker and remove the generator from the grid and also throttle the steam from the reactor to the turbine using valves and also modulating the control rods in the reactor if needed. Man that is a lot of words and somewhat over simplified. Hope it helps.