=Paper=
{{Paper
|id=Vol-2763/CPT2020_paper_s2-1
|storemode=property
|title=Analysis of the actions of NPP personnel in making decisions
|pdfUrl=https://ceur-ws.org/Vol-2763/CPT2020_paper_s2-1.pdf
|volume=Vol-2763
|authors=Maria Berberova,Aida Khakimova,Oleg Zolotarev
}}
==Analysis of the actions of NPP personnel in making decisions==
https://ceur-ws.org/Vol-2763/CPT2020_paper_s2-1.pdf
Analysis of the actions of NPP personnel in making decisions
M.A. Berberova1, A.Kh.Khakimova2, O.V.Zolotarev3
maria.berberova@gmail.com | aida_khatif@mail.ru | ol-zolot@yandex.ru
1
MIREA - Russian Technological University, Moscow, Russia
2
ANO «Scientific and Research Center for Information in Physics and Technique», Nizhny Novgorod, Russia
3
ANO «Russian New University», Moscow, Russia
The operational experience of nuclear facilities shows that personnel reliability has a significant impact on safety. We consider the
reliability of the staff as the property (ability) of the staff to accurately and timely perform the necessary actions prescribed by the
operating instructions, both during normal operation and in an accident. Personnel Reliability Analysis (PRA) is one of the significant
tasks of probabilistic safety analysis. There are problem situations at NPP: the analysis methods and techniques used, the variety of
solving tasks, the wide range and diverse nature of errors that a human operator can potentially make, the numerous factors affecting
the probability of a particular error. All this makes it necessary to develop an automated personnel reliability analysis system that can
support a specialist performing probabilistic safety analysis (PSA) in terms of performing the reliability analysis of the human
operator, to ensure the required accuracy, quality and completeness of the results of the personnel reliability analysis.
Key words: personnel, the most dangerous accidents, personnel reliability, stress, normal operation, emergency.
perform various stages of the PRA requires manual
1. Introduction processing by the executor of large amounts of
The current practice of performing personnel information presented in the form of tables and graphs,
reliability analysis during PSA involves the use of a which increases the analysis timeline and reduces the
number of methods of qualitative and quantitative PRAs, quality of its implementation.
as part of a structured procedure for their application.
2. Decision making by the NPP operator
PRA contains numerous levels and stages. In particular,
the formation of a list of personnel actions, a selection The operator's activity consists of a set of sequential
analysis and a detailed analysis of the most significant actions to develop a solution and implement
actions of the personnel, the determination of the management.
probabilities of an error in the performance of actions, The development of a solution is a process that
the analysis of the relationships between the actions of consists of three stages [1]:
the personnel, the analysis of the possibilities to correct 1. Information search (perception of information)
the mistake made, and the assessment of the uncertainty (table 1).
of the personnel reliability indicators. The reliability of 2. Information preparation of decision making (table
the human operator depends on a combination of factors, 2).
and the most important for analysis used to be the 3. Decision making (table 3).
available time, stress level, and staff qualification level.
Currently, the application of these methods to
Table 1. Information search
Actions Operations The inclusion of psychological processes
Search eye movement, signal extraction from the
Signal Detection Attention, signal and background perception
background
Comparison with the standard Feature Comparison Visual thinking, random access memory
Identification of similarities and differences,
Identification identification of essential features, categorization, Operational thinking, long-term memory
memorization
Table 2. Information preparation for decision making
Actions Operations The inclusion of psychological processes
Information processing about the problematic The operation of constructing a figurative-
Visual action, visual thinking
situation conceptual model (FCM) of the situation
Search for essential information. Highlighting Image conversion operations, comparisons,
from background information. Situation detection of similarities and differences, RAM. Long-term memory.
classification identification of essential features, categorization.
Compilation of information. Building an FCM Operations to convert FCM to a form suitable for
Operational thinking. Visual thinking.
situation. decision making. Selection of evaluation criteria.
Table 3. Decision making
Actions Operations The inclusion of psychological processes
Objective definition Objective formation operations Long-term and random access memory. Conceptual and image thinking
Determining the conditions for achieving Operations formulating conditions
Operational thinking. Theoretical thinking
the objective for achieving the objective
Develop a solution strategy. Choosing Comparison of different solution
Long-term memory. Theoretical thinking
the best strategy methods
Copyright © 2020 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY
4.0)
At the first stage, it is very important to respond to of action, errors are usually associated with a
alarms as quickly as possible and to find the source of the combination of various forced or temporary factors.;
accident. 2. Rule Based Actions - Actions taken in familiar
Table 3 demonstrates the next stage. situations. Based on previously worked out
If at the first stage it is important to notice the sequences of actions that are detailed in the
accident, then at the second stage operator will have to instructions and / or obtained from experience or
evaluate the current situation. At this stage, it is training. Actions by rules are less developed than
extremely important to analyze the situation quickly and actions based on skill, because they are performed
correctly. less frequently and are more complex and often
Table 4 demonstrates the next stage. require increased conscious control. Errors in this
Table 4. Areas of error probabilities considering the types of type of action are associated with incorrect diagnosis
behavior of the situation, which leads to the use of the wrong
Operator Behavior Types Error Probability Areas rule or instruction;
1. Based on experience Pr = 10-4 - 10-2
2. Based on rules (instructions) Pr = 10-3 – 0.1
3. Knowledge-based actions - Actions performed in
3. Knowledge based Pr = 10-2 - 1 emergency situations when existing rules and
experience cannot be applied directly. There are no
Before performing actions aimed at eliminating the ready-made instructions for these actions, they are
emergency, the operator compares various solutions to based on general knowledge, and they must be
the current situation (from possible) and selects the executed in real time. Errors in this type of actions
optimal. are the result of the limited time to make decisions
and perform actions, as well as insufficient or
3. Types of staff behavior incorrect knowledge.
Table 4 presents probability domains for the
For rapid assessment of personnel reliability, used
described types of behavior [2, 3].
primarily for screening analysis (screening) to determine
Preliminary assessments of personnel post-emergency
dominant events, error probability domains they apply
actions (in response-response to an initial event) used in
considering the types of behavior (cognitive modeling)
PSA are expert screening [2-5].
required for each operation [2, 3]:
A logical scheme to help in deciding what type of
1. Skill-based actions - Automated actions. They are
mental activity a person’s actions are shown in Fig. 1.
performed strictly according to the scenarios that are
set out in the instructions (similar, for example,
driving a car along a familiar route). With this type
Fig. 1. A logical tree to determine the prevailing type of personnel actions in solving the problem
4. Types (mechanism) and forms of personnel of behavior:
errors − oversight / omission - an action leading to an
unintended result due to an error during performing.
Personnel errors modeled in the PSA are usually This kind of error usually refers to skill-based
divided into the following types related to different types
actions; operations performed, number of steps, availability
− delusion is an intentionally performed action, but the of a written instruction, its format (descriptive or
intention is incorrect. This is a typical mistake in symptom-oriented), quality of presentation, degree
assessing a situation or in planning a response, of detail, etc.);
leading to the execution of incorrect actions. This − training / experience;
type of error refers to actions based on rules or − human-machine interaction;
knowledges. − interaction / size (composition) of the group of
Personnel errors modeled in PSA are subdivided into operators;
such forms as non-fulfillment errors and execution − information exchange;
errors: − load;
− Failure to comply: personnel error consisting in − stress.
failure to perform one or more prescribed actions. Not all of these factors are directly applicable to each
Typically, a failure error is a failure by the operator of the analyzed personnel errors. Additional factors not
to take the required security system into operation; included in this list may be considered.
− execution error: personnel error consisting in Depending on the likelihood of the consequences of
incorrectly performing one or more actions, or the accident and the time available to the operator for the
performing any other action / actions instead of intervention, personnel are exposed to different levels of
prescribed ones. Typically, a runtime error is either stress. This directly affects the likelihood of correct or
an inappropriate termination of a required security erroneous actions by personnel to troubleshoot in the
function, or an inappropriate activation of a system event of an emergency. Stress can occur for a number of
or initiation of a security function. reasons: unpredictability of an accident, workload (its
The relationship between the actions of the staff takes level and duration), high noise level (for example, when
place if the result of a specific action depends on the an alarm has triggered), conflicts during work.
previous action or actions. The probability of personnel Stress is not necessarily accompanied by negative
errors in dependent activities should be higher than if reactions. The optimal level of stress will allow for better
they were considered independent. All alarm sequences, concentration, increased attention, which will favorably
which include several personnel errors, are analyzed for affect the work of the operator. At the same time,
their potential dependencies. Whenever possible, “unfavorable” (high) stress will negatively affect the
completely dependent personnel errors are redefined and work of even very experienced operators. The time limit,
modeled as a single event. the difficulty of eliminating the consequences of an
accident, errors, in the case of incorrect diagnosis of an
5. The effect of stress on decision making accident, will only increase the level of staff stress,
The main factors that affect the behavior of personnel which will entail an increase in the likelihood of
and the reliability of their actions are considered in a erroneous actions.
detailed analysis of personnel errors: Fig. 2 shows a graph of the dependence of the
− instructions (the following aspects of instructions are operator's performance on the level of stress experienced
evaluated, which are considered to be factors that by him [6-8].
influence behavior: simplicity / complexity of
Fig. 2. The graph of the dependence of the operator's performance on the level of stress experienced by him
6. Types of motivation for activity Cognitive motivation - a manifestation of interest in
the content of the activity. The process of work attracts a
The following types of motivation for activity are person, the result is important for him of every task.
distinguished [1]: Conflict avoidance is the pursuit of a conflict-free
style of behavior. They distinguish motivation for and the development of recommendations in the
avoiding conflicts with the social environment and with conditions of uncertainty implemented on the basis of
their own principles. studies developed in [9,10].
The prestige motivation is the realization that the
activity carried out is respected and gives weight to the 7. Conclusion
individual. It is expressed in desire to assert oneself. Further planns:
Utilitarian motivation - the possibility of obtaining 1. To continue work on the assessment of personnel
good earnings or other material wealth. actions in the most dangerous accidents with the
Human activity is mobilized in real activity in the emission of thermal neutron sources with a low flux
form of a system of motives leading to actions. density.
Motives are formed and rebuilt in the process of 2. To develop a methodological approach to solving the
professional development of the employee and in his problems of assessing doses of external and internal
daily life. exposure and assessing damage to the population
There are some differenties between situational (taking into account the age composition of the
components of activity that is external, objective and population) living around nuclear power plants
internal, and mental. during the most dangerous accidents involving the
External, objective components are the complexity of emission of thermal neutron sources with a low flux
the task and its compliance (or inconsistency) with the density.
conditions of execution: 3. To develop an atlas of risk metrics and a program for
– equipment and the possibility of its application for monitoring (control) the safety of nuclear power
solving problems; plants.
– deadlines (sufficient or short);
– mission statement. Acknowledgment
Internal, mental components of activity:
– professional training; The reported study was funded by RFBR according to
– functional state (mood, health, fatigue, etc.) for the the research projects № 18-07-00225, 18-07-00909, 18-
duration of the task. 07-01111, 19-07-00455, 20-04-60185.
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About the authors
Berberova Maria A., PhD, docent, MIREA - Russian
Technological University, Е-mail: maria.berberova@gmail.com
Khakimova Aida Kh., PhD, docent, Kama Institute
(Naberezhnye Chelny, Russia), ANO «Scientific and Research
Center for Information in Physics and Technique» (Nizhny
Novgorod, Russia), Е-mail: aida_khatif@mail.ru
Zolotarev Oleg V., Ph.D., Docent, ANO HE «Russian New
University» (Moscow, Russia), E-mail: ol-zolot@yandex.ru