Under “Defense in Depth”, the Reactor is the Alamo.

The worse things get, the closer in you have to get. The reactors have their own “heat sinks”. Adjacent to them.

The ANS account reveals that the concept of “ultimate heat sink” being resident in the more distant heat exchangers and emergency diesel generator “radiators” is not relevant to the defence in depth structures built in and around the reactor cores and reactor buildings.

We know from the ANS that after the quake various aspects of the cooling systems were working. According to the ANS after the tsunami, the water level dropped. The water level never recovered no matter what the workers tried.

We know that not only are the valves for the ECCS powered externally from the ECCS (the only components of the ECCS that are subject to that vulnerablity, so much so that they may as well be down by the beach instead at the reactor. ie not depth in depth for those valves. The same event which knocked out the backup power, knocked out the ECCS valves). The HPCI system in reactor 1 could not be invoked by the workers because not only are the valve operating circuits externally powered, but the ECCS controls are as well. After the tsunami there was no way of manually invoking HPCI when it was needed.

At this point I wonder. Is the drop in the water level of reactor number 1 related to the destruction of the primary coolant heat exchangers by the tsunami. We know the ECCS have the primary design goal of making up water level and keeping it below zirconium hydrogen generation temperature. Ergen, AEC, 1967 stipulated working ECCS even in the situation of missile strike. It means that if any of the primary cooling pipes are completely shattered, the operation of the valves both within the ECCS and the primary cooling circuits are capable of isolating the reactors from the breached pipes. When the ECCS is invoked therefore there has to be valving present which isolates the core water from the damaged external pipes – the pipes which flowed to the primary heat exchangers.

The problem with that idea is that when the tsunami knocked out backup power, it wasn’t just the diesels that it took out, but the ECCS valve batteries as well.ANS says DC was down, and batteries are DC.

So the workers tried all the circuits they could to get Reactor 1’s water level up but they failed because 1. they had not power at the controls 2. The automatic system had the same trouble because the pipe valve solenoids had no power at.

Even if the ANS is completely wrong and the major pipe break in the primary coolant circuits for reactor 1 broke badly as a result of the quake. What would happen is this: At that point in time there was power to the valves. The ECCS would independently act to isolate the reactor core from the broken primary loops, and the HPCI system would make up the lost water. Automatically. That didnt happen.

According to the ANS there was no drop in reactor No 1 reactors water level until the tsunami.

It is incredible to my mind that the ECCS DC power units were in the basements of the reactors. The turbines for the ECCS are higher up, in the reactor buildings. Why have the DC power source for the valve solenoids so far from the solenoids? DC – voltage drop over distance. Were the ECCS valves in the basements too? Couldnt be.

Anyway, the NHK report which stated that ECCS was working at all units is very optimistic. When one is in an emergency, anything you do is emergency related.

The view repeated by World Nuclear Organisation and the Lawrence Berkeley National Laboratory lecture are likewise optimistic. In relation to reactor 1, there was not DC power to operate the valves so as to prevent core coolant loss and to provide makeup water. They could pump water in, but the level never did rise again, the water running out through the breach in the, I think, the primary coolant circuit.

The bottom line is, no matter how I might try to visualize it, I am doomed to failure in the specifics. Except this:

What happened at Reactor 1 was, according to the regulators, the companies involved and the governments, impossible under the strict criteria of ECCS acceptance criteria. In theory the ECCS could protect the reactors even if a missile strike took out multiple systems.

So ok, we are the reactor, there is a breach at least as cuased by the tsunami when the heat exchangers by the sea were destroyed . We can pump water in but we can’t isolate the reactor from the breached coolant pipe. Though we could have if we have power, but we dont. The batteries are not “flat”, but they are dead, they are underwater in the basements. And so it goes from there.

When reactor 1 staff needed the HPCI, they couldn’t use it.

To my mind, regardless of what happened at the time of the quake, pipe break, whatever, may or may not have happened. What certainly did happen with the tsunami in the case of reactor 1, is power failure to the ECCS controls and valves. If there had been a major pipe break before the tsunami, after the tsunami, the reactor would no longer be isolated from that pipe break. Because the power to valves was dead. And it was certainly true that the integrity of the primary coolant lines is very greatly called into doubt by the fact that the heat exchangers by the sea were destroyed. One one to imagine that is to see the heat exchange units being ripped from the coolant pipe junctions and connectors. And that’s just a visualization, not an oberservation, I wasnt there. You have to ask how the tsunami would destroy these (allegedly) ultimate heatsinks? If you think about it, a breach in the pipes feeding into the heat exchangers is an obvious option.

So, despite the assurances given to the scientific and lay communities since 1967, through the public brawls of the 1970s, which got quite nasty, through the 80s, and across the century, the world has been assured that come what may, as far as the dudes could imagine, nothing would threaten the core, it would not cause venting, explosions, containment breach or widespread contamination, mass evacs or loss of national food baskets. But just to make sure, they had the theory that radiation was a health benefit.

It turns out, Japan has a written record of massive tsunamis and earthquakes going back to the 1700s and earlier. So Japan buys this “guaranteed in America” technology.

And Japan being Japan has an earthqake and tsunami.

And guess what. I need not go on. Except to say the ultimate heat sinks for the reactors ECCS is the torus and the reactor building heat exchangers, condensers, radiations, whatever you want to call them.

And, also, lo and behold, depsite decades of denial, the BWR suppression pool/torus idea does not work as a containment, it breached in at least reactor 1.

So everyone can rest easy because to cope with of this designed in danger, the NRC has mandated diesel generators at all US reactors which are similar to those Fukushima plants.

I feel sick.

I firmly believe that had a pipe break occurred the ECCS would have coped. If its valves had power. The breach would have been isolated. Until the tsunami came. After that no breach at all would be coped with because the ECCS DC power for the isolation valves was dead at reactor 1 after that. If I can bear to look at the other 3 reactors I will. If the TEPCO document in Japanese shows coolant loss prior to the tsunami with no make up, that would be important.

The plants were doomed as soon as the water hit the electrics.

Not a good look.

I had better state my bottom line. I have always thought that the Mk 1 design would be able to cool a core if the core was covered and if at least water was turning to steam, being cooled in the suppression pool and returned. As soon as the core is uncovered though, that’s it. If all the valves had power, the water in the reactor, including the torus, could be isolated from any broken pipe outside of the reactor. The Torus is an ECCS heatsink. It absorbs heat from the water. In theory it should work. It didnt because the valves lacked juice, and so the broken pipe which occurred as a result of the tsunami, probably when the cooling system plant by the sea was destroyed, could not be isolated. The because of this failure to isolate, the core opened to a broken pipe or pipes where the heat exchangers by the sea had previously been.

Again, tragic and very dumb. Given the water tight guarantees of the period 1967 to 2012.

What I have just written is not going to please anyone. It does not please me.

As well wet electrics for the DC circuits for the ECCS valves, they could not fix a broken pipe in time to stop the worst from happening.

While the workers were waiting for the inevitable, and trying to stop it, the world thought the ECCS was working when it wasn’t.

Who had the idea to tell us that?

What we have here is a failure to communicate.

They really really thought they had built a reactor, but it turned out to be just a uranium smelter set inside a sealed container. So, as they said, to keep us safe.

One Response to “Under “Defense in Depth”, the Reactor is the Alamo.”

  1. CaptD Says:

    As usual a great summation!

    Yet more discussion is needed and as we take part in it I predict yet more “holes” will be found in their nuclear Logic which is now costing the Japanese people somewhere in the neighborhood of 1 Trillion Dollars (US) and has resulted in radioactivity polluting large areas in Japan, of the Planet’s atmosphere and the Pacific Ocean…

    A Nuclear Oops

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