Reply #66: the most critical system in a bwr

[divvy]

The most critical and versatile system in a BWR 3/4 is RHR (residual heat removal system). You can Google this... Wikipedia is very smart. It can do a wide variety of things, but not all at the same time. It has a LPCI mode that can inject into the vessel at low pressures... it can cool the containment with sprays in both the drywell and torus... it can cool the reactor coolant (it has the shutdown cooling mode)... some plants do have a separate shutdown cooling system... it can cool the fuel pool (but needs a spool piece on the ground floor of he RX building installed). There are 2 loops of RHR... getting even 1 loop back would be a huge benefit. Doing so is a lot more than just hooking up power, though. This system has complex controls and interlocks. It is a low pressure system, so you certainly can't use it if you don't have pressure low and under control. The normal fuel pool cooling and normal feed water systems are NSR and normally not seismically qualified. If they are available and can be restored with power, they would be a great benefit. Lighting for workers at night would be very helpful. Installing remote cameras to monitor the systems like the refuel floors would be helpful. Some 120VAC would be helpful to power up the main control room panels and alarms... I am assuming that these control rooms haven't been destroyed... but I can't tell from the pictures I have seen. It is going to require an extensive plan with many electricians to accomplish this. Getting the site dose rates down is probably required before any of these tasks can be attempted. Some plant walkdowns might be required to determine if any of these things are possible... experts may be able to tell from photographs. Replacement systems may have to be installed to perform these functions, but some of them have to be done to stabilize the situation - 1) you have to be able to inject water into the vessel at all pressures being experienced, 2) you need to be able to cool the core to prevent it from re-pressurizing, 3) I assume SBLC has injected Boron... if not, Boron needs to be injected into the core, 4) you need to be able to fill and cool the fuel pool, 5) primary containment should be assessed to see if it is in tact and all necessary valve closures have occurred, 6) you need to be able to cool the suppression pool water (torus)... be able to refill it if necessary. This is the water source for safety system injections and the safety related heat sink. The plants that are relatively stable should definitely have these functions restored asap. It is far easier to do it before severe damage occurs. Working on the most severely damaged plants is not necessarily the highest priority. You have to assess what is possible. All the plants are at risk and reducing the number of catastrophes is worthwhile. All 6 plants are in trouble and need to be assessed for preventative and corrective actions. For example, restoring power will be a lot easier to a relatively undamaged plant. You can't do this without an army of engineers and more workers.