TMI root causes

["Brian Rees" <brees@lanl.gov>]

Sandy wrote:
"The Root Causes of the TMI accident were:

1. Refusing to believe their instrumentation
2. Lack of or inadequate system's training, as well as general 
    overall training and competency reviews
3. Inattention to details
4. No "real" Emergency Plans or Procedures, nor, Emergency Plan 
    training.

All of these issues could have been mitigated with the necessary 
management attention. Of course in the 1980's, the edict was to keep 
the plants running and maximize profits. Overhead $$ were to be 
minimized. Training, while provided, was not detailed at all, and, 
Emergency Exercises, for all practical purposes, were a joke!"


The indication for the motor operated relief valve, (the one that stuck 
open, and directly lead to the rest of the accident) was actually an 
indication that power was supplied to the motor.  When the motor  was 
denergized, the control panel indication was that it had closed.  This 
indication was (initially, and for quite a while) believed. 

The TMI control room had something like 2,000 alarms that sounded during a 
"routine" scram, sorting out the details is not a simple task.  There were 
other indications that, in retrospect, should have had more attention paid 
to them.   Many indications were disregarded later because they conflicted 
with what was expected,  this can be attributed to lack of 
training/understanding.  

There are of course other problems that surfaced during the time we've had 
to look back, but until you're the person who's trying to respond to a 
myriad of alarms, and make the proper decision in VERY short time period, 
it's difficult to really appreciate how fast (literally) hundreds of 
considerations are made. Yes, that's what the operators are paid for, but 
keep their  operating environment in mind along with the events.  I still 
believe that it was the ($$$/"management") operating environment that lead 
to some of the *faulty* decisions that were made (like turning off MCPs 
because they were cavitating). 

We must keep these things in mind, there are times that we (HPs) could be 
susceptible to some of the same traps.

Brian Rees
brees@lanl.gov