The Ugly Truth About Three Mile Island
Last Saturday was the 30th anniversary of the accident at Three Mile Island, the worst accident in the [known] history of civilian nuclear power in the United States. There have been a handful of diaries in the past week marking this anniversary. By Kossacks who remember the event, know people who were impacted by the event, an ongoing series with a lot of linked sources for the curious, and even a short diary by me about how much of the truth has been 'lost' over the decades.
In several of these diaries a cadre of pro-nuclear shills descended to defend the nuclear industry against its own worst mistake. Most of these pro-nukes have been at DKos for awhile, and have made no secret of their position. Which is fine, so long as the discussion is general. When it comes to something so historically significant as the accident at Three Mile Island, the standard propaganda, half-truths, false dilemmas, hyperbolic fear-mongering, ridiculous lies and orders to STFU are less well tolerated.
I served as an hp technician in the initial recovery operation, from back when there were still helicopters taking off every 15 minutes to map the release plume, inevitably blowing open the whole back end of the field-sized M*A*S*H tent up to chill everyone dumb enough to sit at that end for their meal. The fog was pea-soup thick during the 7pm to 7am shift, an early spring temperature inversion keeping the Susquehanna Valley blanketed and eerily still. As it had been on the morning of the accident and remained for a solid week. Best catch-up work was done overnight, the place was a regular circus during the day. I processed the doses at the dosimetry trailer for about ten days, then moved onto the Island when the TLD readers (Met-Ed's and NRC's) moved back on-site.
What I learned about the accident while on site didn't match what came out that October in the Kemeny Commission reports, though that didn't surprise anyone who knew the truth. This is not an industry noted for its up-front honesty with the public, the regulators or local officials in the best of times. TMI was the worst of times, so matters of truth and reality naturally went all the way south. The industry, beset by 'the usual' Military-Industrial Complex cost overruns and due date waivers despite heavy subsidies, had been in some real trouble before the accident. Everyone knew things weren't going to get any better now, not with that pile of molten slag seething in a containment structure so hot no human dared open a hatch for more than 3 years.
It was a nuke's worst nightmare. Sure, the public and the press and the Pennsylvania officials were all scared too, but they weren't told the whole story, had no idea at the time how bad things really were. The truth, after all, was a matter of 'legitimate' national security concern, mostly because the bad old Cold War was still raging and this industry above all others enjoyed the cover of enforced secrecy on its minor mistakes and major fuck-ups. TMI was a major fuck-up.
Anyway, in between all the name-calling and epithet-throwing and whining and kicking and screaming (as if they're all still stuck in their 'terrible twos'), there have been demands that I justify my charge that not all the control rods fell during the emergency scram sequence eight seconds into the accident at TMI. And while I know from my career as Mom it's not wise to give in to the demands of spoiled toddlers, this little factoid is something that changes everything about what the public has been told about the accident. So it's time for this to be laid out clearly, in hopes that it will at least change the nasty tone of our DKos live-in nuclear shill squad.
Here are some assertions by said shills that are directly impacted by the FACT of scram failure:
Joffan, parroting the official lie -
TMI scrammed without incident, stopping the fission totally. The fuel melted because reactor cores do not cool down immediately due to the intense radioactivity of the fresh fission products which produce a great deal of heat for a few hours, and require active cooling. The operators stopped this cooling process due to misinterpreting the problem.
Human factors in operator training, interfaces, alarm design and notification were a big lesson learned from TMI. Sensor technology has improved immeasurably too.
And from bryfry, also reciting the Kemeny Creed:
The fission stopped less than a dozen seconds into the accident.
Now, these folks (and there are more, I'm just too lazy to go back through all the diaries to lift assertions I'm about to explode like hydrogen and oxygen) could just be gullible. Or they could have had this junk drummed into their heads by Naval educational equivalents of drill sergeants in nuke school, which is where most civilian nuclear operators and technicians get their real training. Or maybe they really are shilling for some overpaid PR firm hired by the nuclear lobby to sell nukes to a public disinclined to buy them, lies being their stock in trade. Bottom line is this...
If the reactor scram failed at TMI, there was ongoing fission in the reactor and this forces an entirely different interpretation of events as they transpired over the first hours. Clear indications that the scram failed have been available all along based on the admitted condition of the plant after the accident. Things such as the FACT that the 3-month old core managed to produce ~50% of its total core inventory of fission products [h/t Bettis Laboratory analysis of RCS sample 3/30/79] during the accident, before the water boiled out and the center of the core disappeared and the meltdown ensued in earnest. You only get fission products from fission.
You'd also think at least a few of these shills might have wondered at some point in their careers why one of the very first enforced retrofits ordered by the NRC in the wake of the accident was to do away with the gravity feed control rod system and install mechanical assemblies to force those rods into the core. Or, while reading the Kemeny accident scenario and sequence of events, how five Navy trained operators could have completely missed the FACT that their steam generators had boiled dry less than 2 minutes in. Or why those same operators would specifically request the PORV discharge outlet temperature 5 times over the first two hours and twenty minutes of the accident if they didn't know the PORV was open. Such things may be terminally obscure to the average member of the public, but no real nuke worth his or her salt would overlook them without a double take and large question marks appearing in thought bubbles over their heads.
At any rate, here's the meat of the matter per scram failure at Three Mile Island. Enjoy...
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Kemeny made a particular point of repeating - several times in several places - that 69 of 69 control rods fell. From the Prologue of the Report of the Presidents Commission on the Accident at Three Mile Island, paragraph 1, page 83 [October, 1979]:
TMI-2's reactor contained 36,816 fuel rods - 208 in each of 177 fuel assemblies. A fuel assembly contains not only fuel rods, but space for cooling water to flow between the rods and tubes that may contain control rods or instruments to measure such things as the temperature inside the core. TMI-2's reactor has 52 tubes with instruments and 69 with control rods.
Paragraph 2 of the same page describes what 'scram' means, and how power level is controlled:
Control rods contain materials that are called 'poisons' by the nuclear industry because they are strong absorbers of neutrons and shut off chain reactions. The absorbing materials in TMI-2's control rods are 80 percent silver, 15 percent indium, and 5 percent cadmium. When the control rods are all inserted into the core, fission is effectively blocked, as atomic nuclei absorb neutrons so that they cannot split other nuclei. A chain reaction is initiated by withdrawing the control rods. By varying the number of and length to which the control rods are withdrawn, operators can control how much power a plant produces. The control rods are held up by magnetic clamps. In an emergency, the magnetic field is broken and the control rods, responding to gravity, drop immediately into the core to halt fission. This is called a 'scram'.
From page 90 of the Prologue, which summarized the accident:
Pressure continued to rise, however, and 8 seconds after the first pump tripped, TMI-2's reactor - as it was designed to do - scrammed. Its control rods automatically dropped down into the reactor core to halt its nuclear fission.
Less than a second later, the heat generated by fission was essentially zero.
To flesh this out we can turn to the Kemeny Commission's Public Information Task Force, which produced a concurrent account written for the public by member Mark Stephens. From page 10 of that account:
Within nine seconds, 69 boron and silver control rods fell into place among the 36,816 zirconium fuel rods with their millions of pellets of uranium dioxide fuel. The rods absorbed neutrons to stop the chain reaction. The falling into place of these rods, called a 'scram', worked as it should. The reaction stopped.
Stephens underlined the point about how many control rods fell on page 13:
In a graphic display, the rod status showed lines of red lights to symbolize the 69 control rods. As the reactor shut down, these lines of lights began to turn on, following, from top to bottom, the descent of the control rods into the reactor core.
Stephens' work was carefully vetted by resident experts to ensure his account's fidelity with the Commission findings. These reports were a regular best-seller for the GPO that year and well into 1980.
By mid-1982, however, they'd finally achieved entry to the containment and the vessel, lowered a robot camera into it to see what was what. The AP reported on June 26 of that year -
Officials at Three Mile Island nuclear power plant said Friday that although testing has gone well so far, it is still too soon to say what shape the plant's crippled reactor is in.
"We have a lot of good vibes, but we're not ready to draw any overall conclusions on the condition of the reactor and we may not from these tests alone," TMI spokesman Doug Bedell said.
Technicians are hoping that they will be able to move eight control rods into the reactor core one at a time. So far, they have moved four of them to different depths inside the reactor.
When the reactor was operating properly, each 12-foot rod - actually a bundle of 16 pencil-thin metal rods - was used to be sure that the nuclear fuel was spent evenly during the fission reaction. They were in a raised position when the accident occurred, and have stayed there until the tests started.
Sixty-one other rods, used to start and stop fission within the 40-foot reactor, were dropped into the core to shut down the fission within the 40-foot reactor, were dropped into the core to shut down the reactor during the accident.
Now, you shills may feel a strong need to defend this discrepancy between what was reported by the appointed investigators of the accident in October of '79 and what was real inside the reactor in June of '82, but anyone who knows anything about running a nuclear reactor is going to know right away there's no such thing as a group of control rods that don't have to fall during a scram.
The group that didn't fall at TMI-2 was reported by the conductors of the testing that 'discovered' them - a consortium calling itself GEND [G for GPU, E for Electric Power Research Institute, N for NRC, D for DOE] - to be rod group 8, ringing the center of the core. Which, the same consortium discovered during the tests, turned out to be "missing." This they called the "void at the center of the core," which I always thought would make a great sci-fi title...
But this is something simple enough for a 6-year old to grasp.
69 - 8 = 61
61 of 69 control rods does not a successful scram make. Remember that nifty heads-up display in the control room described so colorfully by Stephens? It wasn't literary license, the display existed. It did show graphically the position of all 69 rods. Do any of you still believe the operators could have overlooked the FACT that the scram had failed?
Now... go back and re-read the event sequence with this in mind. See if you come out the other end still believing the whole accident can rightfully be laid at the feet of these terminally ill-trained individuals who didn't know their ass from their PORV. Then look around at the way things work in the halls of power in the real world, who takes the falls for malfeasance of higher-ups. Finally, look up the word "Patsy" and its synonym "Scapegoat." See if the terms fit.