ML17277B309

Function & Task Analysis of Emergency Operating Procedures.

ML17277B309
Person / Time
Site:	Columbia
Issue date:	02/17/1984
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17277B308	List: ML17277B307 ML17277B309 ML17277B310
References
PROC-840217, NUDOCS 8402230229
Download: ML17277B309 (18)

Text

FUNCTION, AND TASK ANALYSIS CF THE WNP-2 EMERGENCY OPERATING PROCEDURES

" WASHINGTON PUBLIC POWER SUFPLY SYSTEM 8402280229 840217 PDR ADDCK 05000397,, F,'PDR Ij TABLE OF CONTENTS

1.0 INTRODUCTION

.~l~~~~~~~~~1~~~~~t~~~~1 2.0 DEFINITIONS.

~~~~~~~1 3.0 METHODOLOGY.

~~~~~~~3 3.1 General......

~~~~~~~3 3.2 Identification of Princial Control Functions.........

4 3.3 Identification of Decision and Action Functions.......

5 3.4 Decision Analysis.3.5 Action Analysis.~~~~~6~~~7 3.6 Classification of Information................

8 4.0 AFPLICATION.

9 5.0 SLWARY.~~~~~~~~~~~~10 l.0 INTRODUCTION This docuoant describes a methodology f'r function and task analysis of WP-2 EOPs.Applications for the results of the analysis are also dis-cussed.2.0 DEFINITIONS Action Function: An operator function involving a con-scious movement, operation of con-trois, or execution of a series of procedural steps.Example: "Inject boron into the RPV with SLC." Control Requirement:

The specific controls required to en-able the operator to accomplish an action.Examples: Pump breaker con-trol switch, valve control switch, selector switch.Decision Analysis: A form of task analysis in which ope-rator decisions are identified and systematically examined to identify information requirements.

Page 1 of 11 Decision Function: An operator function involving a determination, evaluation, or judge-ment through which a procedural branch path is selected.Example: " f sup-pression pool temperature cannot be maintained below the Heat Capacity Temperature Limit..." Function: A higher order activity by which the plant operating crew meets the objec-tives of the operating procedures.

Within the context of this document, functions include decisions and actions.Information Requirement:

Knowledge of system or plant status required as an input to a decision.Examples: Pump status, breaker stat-us, valve lineup status, RPV water level status.Page 2 of 11 Instrum ntation Requirement:

Specific parameters, displays, and design characteristics required to fulfill an information requirement.

Example: Pressure indicator with a range of 0-150 psig.Task: A well defined subdivision of a func-tion;a specific activity contributing toward the accomplishment of a func-tion.Examples: Closing a valve, tripping a breaker.Task Analysis: A systematic process by which operator tasks are identified and examined in terms of the conditions, control, in-'trumentation, skills, etc.associated with the task.3.0 METHODOLOGY 3.1 General The EOPs specify the emergency functions of the plant-operating crew.Through analysis of these functions and their constituent tasks, control and information requirements necessary to support the performance of the EOPs will be determined.

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The function and task analysis of the,EOPs will be conducted in the following steps: (1)Principal control functions will be ide<<tified.

(2)Decision and action functions will be identified for each prin-cipal control function.(3)Control and information requirements will be identified for each decision and action function.The result of the function and task analysis will be identification and application of action and decision functions and the control and information requirements necessary to performing the procedures.

3.2 Identification of Princi al Control Functions The new, symptomatic BWR EOPs typically define principal control functions.

These functions generally correspond to the grouping of procedural steps within the EOPs.Examples include RPY water level control, reactor power control, suppression pool level control, and primary containment pressure control.Page 4 of ll

'I~~

3.3 Identification of Decision and Action Functions-The EQPs specify performance of the principal control functions in 8 series of procedural steps containing decision and action func-tions.These decisions and action functions will be separately identified for analysis in terms of control and information require-ments.To facilitate subsequent analysis, the decision and action functions identified in the functional analysis will be classified as follows: Dl-Decisions which require comparison of a parameter to a pre-determined value or limit, such as"above" or"below".D2-Decisions related to system status, such as"open" or"initi-ated".03-Decis'ns based upon a procedural requirement, such as"If Boron Injection is required".

04-Decisions that are judgmental or which require an estimation of the future state of parameters or system status.Examples in-elude"If RPV water 1 vel cannot be maintained","If RCIC is available", and"If adequate core cooling can be assured".Page 5 of 11 Al-Actions that are not directly conditioned upon an explicit decision process, such as"Open the discharge valve" or"Monitor RPV water level".A2-Actions that are directly based on the less complex decision functions (type Dl and D2), such as"If pressure is below 10 ps'.g then shop the pump" A3-Actions that are directly based on the more complex decision functions (type DZ and D4), such as"If reactor power is above the AFRM downscale trip or cannot be determined, then trip the recirculation pumps".3.4 Decision Anal sis Before making a,decision, the operator oust gather and process a set of information.

This set includes both information explicitly identified in the step itself such as plant variables, system para-meters, and associated limits, and certain supplemental or implicit information.'mplicit information may be required to varying degrees, depending upon existing plant conditions, and on system or component availability at the time the decision must be made.'age 6 of ll

~~In the decision analysis process, each identified decision function will be examined in terms of the information, both explicit and implicit, the operator requires to effect an evaluation of plant a conditions and make"he decision.Explicit information needs may be obtained directly from the EOP step itself.Implicit information needs must be derived through analysis of the operator's expected response, system characteristics, and procedural requirements.

Actions specified in the EOPs generally require the performance of a particular act or the execution of a series of procedural steps.In the task analysis process, each identified action function will be examined in terms of its constituent tasks.Controls gequired for the performance of each task may then be identified using available technical reference material, operator input, and installed equip-ment.In addition to identifying control requirements, analysis of operat-or actions will also identify a set of implicit information require-ments.Once the action has been taken, the operator must obtain feedback information to verify that the action was performed pro-perly and that it resulted in the desired effect.This feedback Page 7 of 11 information may be the same set of information processed to make the decision leading to the action, an independent set, or more likely, ari intersecting set.It necessarily includes considerable informa-tion pertaining to system status, system availability, component operating status and system performance., All of this information falls into the category of implicit information.

3.6 Classification of Information To facilitate subsequent analysis, the information requirements identified through the analysis of operator decision and action functions wiH~be classified as follows: Il-Directly measurable plant.parameters, such as RPY water level, suppression pool temperature, or RCIC steam.line pressure.I I2-Parameters derived from one or more type Il parameters, such as RPV saturation temperature or the Meat Capacity Temperature Limit.I3-Type Il parameters as a function of time, such as RPV cooldown rate.I4-Parameters related to system status, such as valve position or breaker status.Page 8 of 11

~~

~~As previously discussed, the information may be explicit, implicit, or both, depending upon the decision or action function which requires it.4.0 APPLICATION A sample functional analysis is illustrated in Figure 1.The format and content shown is for illustrative purposes only and is not designed to be prescriptive.

The results of the function and task analysis will be used in the follow-ing applications: (a)Identifying operator information and instrumentation requirements for refining the Graphics Display System (SPDS).I (b)In conjunction with the DCRDR, identifying operator control, infor-mation and instrumentation requirements for emergency operating procedures.(c)Verifying provision of instrumentation under Regulatory Guide 1.97.(d)Refining plant-specific emergency operating procedures.

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~~~q (e)Identifying performance and knowledge requirements f'r development of operator training programs.5.0 RMMARY Through functional analysis of the WNP-2 emergency operating procedures,'principal control functions and specific emergency response action and decision functions will be identified.

The identified action and deci-sion functions will then be analyzed to detemine the information and con-trol requirements necessary to support the accomplishment of these func-tions.The information and control requirements thus determined are used to define or prioritize requirements for procedures, training, and con-trol room system improvements.

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