Photograph of a GE Mk1 Coolant Injector located at each Reactor

HPCI pump used for high pressure emergency coolant injection to the reactor, this pump is turbine driven by steam
Source: BWR Plant Photos – inside and outside
http://www.nucleartourist.com/areas/bwr-in1.htm

hpci

The tragedy is the valves in the coolant pipes these and similar devices in the reactor buildings rely on are controlled by low current DC electricity which the emergency could supply but does not. As a result these critical solenoids run of batteries in emergency operation. The life and survivability of the batteries time limit the operation of such emergency backup cooling such as that provided by the High Pressure Coolant Injection units. The alternate cooling circuit has it own “heat sink” in the reactor buildings. In emergency settings when the emergency systems should be running, there are more than one “heat sink” . There is more than one pump.

The ECCS did not work because the valves are not provided secure DC voltage.

But at the design stage they should have been, for the ECCS is required to be able to operate during emergency.

It is not beyond intelligent design to provide integral inviolate power to the solenoids, as is in fact supplied to the HCPI pumps.

The 50 cent concept of uninterruptible power supply was not applied.
The maximum time any of the low current DC solenoid circuit batteries lasted for was 70 hours (American Nuclear Society). No matter how that time limit is justified, it is insufficient, for the ECCS as a whole is required to last for as long as needed. The ECCS system, like any other system, is as reliable as its weakest link. If time defines the outcome, why design an ECCS that is time limited as dictated by the vulnerability of batteries? If it were a plane it would not be allow to fly. Why was not the reactor used to power itself and its systems. Why rely on the grid in emergency when in the first instance the reactor power the grid? There is a steam turbine in the reactor buildings. It is there to power the emergency coolant pumps. Why can’t it also include DC generation for the pump valves? The pumps need open pipes after all.

Other wise the thing fails catastrophically. Now, I don’t like reactors. But I dont want them to blow up. One would have thought the companies that made these things wouldn’t want catastrophic failure either.

How long it took TEPCO to disclose to the Prime Minister that the emergency cooling system could not be switched on and maintained I do not know. Does the Prime Minister know that the fate of the nation depends upon juice being present at an electrical contact, so that water might flow?

Probably not.

One Response to “Photograph of a GE Mk1 Coolant Injector located at each Reactor”

  1. CaptD Says:

    A Great photo and one which I believe helps others that have not had the chance to see the actual components understand the situation.

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