ML17062B065
| ML17062B065 | |
| Person / Time | |
|---|---|
| Issue date: | 05/24/1991 |
| From: | Rosenthal J NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| Shared Package | |
| ML17062B067 | List: |
| References | |
| NUDOCS 9106040261 | |
| Download: ML17062B065 (10) | |
Text
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n0c ENCLOSURE 1
UNITED STATES l
'LEAR REGULATORY COMMlSSlOh WASHINGTON, D. C. 20555 NY 24 1991 MEMORANDUMFOR:
Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data FROM:
SUBJECT:
Jack E. Rosenthal, Chief Reactor Operations Analysis Branch Division of Safety Programs Office for Analysis and Evaluation of Operational Data INTERIMREPORT ON HUMANPERFORMANCE STUDY PROGRAM In 1990, AEOD initiated a program to enhance the staffs understanding of factors affecting human performance during operating events.
The program was announced in a March 16, 1990, memorandum to the Regions and NRR and was consistent with plans earlier described in SECY-89-183.
The purpose of this memorandum is to summarize our progress with the program so far.
Introduction During 1990 we conducted six onsite studies of operating events, one of which was in support of an AITinvestigation.
An interim report on the results of those six studies was prepared by our contractor and is enclosed.
The report summarizes the study results, analyzes event characteristics, and describes problems identi6ed.
We have tried to get feedback on our conduct of this program.
On February 25, 1991, we met with Tom Sheridan of the Massachusetts Institute of Technology and Ali Mosleh of the University of Maryland to obtain their comments and advice on ways to improve the studies.
Both Drs. Sheridan and Mosleh stated they were pleased that the NRC had undertaken the program and thought the study results would continue to be valuable. A March 28, 1991, memorandum includes notes on that meeting and a March 12, 1991 letter contains comments by Dr. Sheridan.
Copies of the memorandum are available.
We held telephone conferences with management at the sites where we had performed the most recent human factors studies to obtain their comments.
We asked whether the study reports were accurate and useful, and where improvements might be made in the future. In general, licensee personnel felt the studies were beneGcial and that they gave different perspectives on the events.
On April 19, 1991, we presented the results of our program to the ACRS. ACRS members appeared to be interested in the program and await further results.
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Thomas M N v k Stud Resul All the events studied were found to have been the result of one or more initial conditions that made the system more vulnerable (these factors are termed "plant conditions") and one or more factors that influenced operator performance in responding to the event (these factors are termed "operator resources").
Con6guration and work control and maintenance were the most common plant condition factors.
There were many operator. resource factors.
In fact, the events investigated were complex in the sense that they were influenced by an average of more than four of these factors.
Thus we conclude it is inappropriate to focus on a single "root cause" and develop corrective action that addresses a single factor.
There is a lot to be learned from these human factor investigations and licensees should be encouraged to perform such investigations, We have made several observations and arrived at some tentative conclusions based on the study results obtained so far and feedback we have received.
Briefly, they are as
- follows, Teamwork (command and control and communications) is crucial when responding to events.
Data indicate that the best responses to events are made by teams rather than individuals. The best teams are made up of individuals who work and train together.
Systems and task awareness are important in avoiding and in responding to events.
The operating crew and other involved personnel should be fuQy aware of work that is underway and how it might effect plant operation.
This is particularly important when performing infrequent activities and evolutions.
Good performance by operating crews depends on both knowledge-based and rule-based performance and training is needed to develop both.
Simulator training in particular should not focus exclusively on rule-based performance in emergency operations, but should also consider performance in less well-de6ned situations, such as problems encountered during infrequently performed operations, shutdown operations, and multiple-failure scenarios.
The procedures and training for shutdown events were not as complete as for operating events.
Upgrade programs appear to be warranted considering that shutdown events contribute a significant portion of total risk.
While procedures and training for operating events were better than for shutdown events, there were weaknesses.
Improved procedures would have been useful in responding to an anticipated event (SRV failure) or an event where previous operating experience should have identified and corrected weaknesses (restart of turbine driven feedwater pumps and feedwater/condensate system realignment following a reactor trip).
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Thomas M N vak The decision making process seems to work best when operations are directed by a leader who is receptive to input from other team members.
This is consistent with good teamwork Fatigue and stress can be important factors in performance.
Limits on working hours have not been effectively implemented for all workers who have a role in safety-related activities.
There was no evidence in any of the events studied that the STA played an important role. While concepts regarding the STA varied from site to site, there was no consensus about the intention of the requirement for the position. The STA did not participate effectively in three of the four operating events, because he either was not needed or had other duties that prevented his participating, In contrast, during another event a systems engineer provided the overview insights expected f'rom the STA, and identi6ed the cause of the event.
Requirements regarding the STA position should be reconsidered at this time.
At some sites the control room organization structure, combined with requirements for event reporting and EOP actions, results in a "loss of redundancy" in the decision-making process.
For example, during an event at one plant, the operators were busy at the panels, the STA was making notifications, shift foremen were operating valves in the plant, and the shif't engineer (shift manager) was directing EOPs.
Thus, even the person presumed to be maintaining the "big picture" perspective had several other responsibilities to carry out. This did not appear to be an eKcient use of the available resources.
Operating crews responded better to events during normal power operations than during operations while at low power or shutdown.
This is because there are better procedures and training for power operations.
Consideration should be given to upgrading requirements regarding shutdown operations.
In certain instances operations personnel have relinquished full control of operations during shutdown activities.
Operations management should be constantly vigilant to ensure this does not occur.
The response to a number of events was complicated by operators'eluctance to use safety grade equipment.
In one event, operators were reluctant to close the MSIVs because they anticipated difficulties in reopening them ifneeded.
In another event, operators were reluctant to use SRVs for pressure control because of potential damage to tail pipes and hangers.
Correcting these hardware deGciencies would help to unburden operators in responding to events.
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Thorn M N vak Even af'ter human factors upgrades to control rooms were made as a result of detailed control room design reviews, weaknesses still exist.
For example, weaknesses at one plant included feedpump indicating light differences, lack of HPCI injection Qow instrumentation, and location of level instruments.
In the three of the four events that occurred during power operations, automatic systems would have provided an adequate response to the event.
In the three shutdown events, operator action was necessary to restore the plant to a safe condition.
We plan to continue this event study program. A supplementary report willbe issued on this program at the end of 1991.
Jack E. Rosenthal, Chief Reactor Operations Analysis Branch Division of Safety Programs Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated CC:
See attached
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Thorn M.N v k CC:
John Franz, Station Manager Peach Bottom Atomic Power Station R. D. 1, Box 208 Delta, Pennsylvania 17314 J. W. Hampton, Station Manager Catawba Nuclear Station 4800 Concord Road York, S.C. 29710 Joseph F. Firlit, Vice President - Nuclear Generation Nine Mile Point Nuclear Station P. O. Box 32 Lycoming, New York 13093 E. D. Eenigenburg, Station Manager Dresden Nuclear Power Station R.R. P1 Morris, Illinois 60450 Kurt Kofron, Station Manager Braidwood Nuclear. Power Station Route 1, Box 84 Braceville, Illinois 60407 Richard L Bax, Station Manager Quad Cities Nuclear Power Station 22712 206th Avenue North Cordova, Illinois 61242
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