ML19275D946
| ML19275D946 | |
| Person / Time | |
|---|---|
| Issue date: | 01/22/1980 |
| From: | Moore V Office of Nuclear Reactor Regulation |
| To: | Mattson R NRC - TMI-2 OPERATIONS/SUPPORT TASK FORCE |
| Shared Package | |
| ML19239A281 | List: |
| References | |
| FOIA-81-405 NUDOCS 8005140683 | |
| Download: ML19275D946 (2) | |
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f January 22, 1980 Note to Roger Mattson TMI TASK ACTION PLANS, CRITERIA FOR AUTOMATIC AND MANUAL ACTIONS In the TMI Task Action Plans there appears to be a gap in the consideration of the man-machine interface.
Consideration of which functions should initiate automatically and which should be manually initiated is neglected in system design.
Considerable attention is given in the plans to control room design and operating procedures so as to make the operator more effective.
- However, these studies take as given the operations required of the operator.
The operations required of an operator under normal and emergency conditions are largely detennined by the design of systems, particularly instrumentation and control systems.
In the deliberations of the Panel on Smart Instrumentation at the recent NRC/IEEE Working Conference, it was clear that there was no agreement on what the function of the operator should be. Although the issue was not faced directly, certain speakers seemed to consider the operator the first line of defense.
Safety actions should be taken manually, and automatic controls should be provided only for actions beyond the capability of an operator.
Other speakers seemed to con-sider the operator the last line of defense.
They would have the plant controlled and protected automatically and would have the operator monitor the automatic systems and take action only when automatic systems fail.
These extremes envision two rather different rcles for the operator: (1) as an element in the control loop or (2) as a supervisor and back-up for automatic systems.
The nuclear navy with its avoidance of automatic systems favors the former role for its operators, while the chemical industry with its automated plants seems to cast the operator into the latter role.
It is likely that neither of the extremes is an appropriate role for the operators of central station nuclear power plants. Most would probably agree that automatic systems should do what they do best and operators should do what they do best if we could agree on what each does best.
In the past, NRC has permitted functions to be performed manually if adequate time and infor-mation is available to the operator without much consideration of whether the function could be performed more reliably by an automatic system.
I believe that a task should be included in the plan to develop criteria for determining which safety actions should be performed automatically and which