Presentation on theme: "Defining Investigation Extent of Condition/Cause Scope a New Approach"— Presentation transcript:
1 Defining Investigation Extent of Condition/Cause Scope a New Approach Steve DavisThe Excellence Engine, LLCJune 2010
2 a.k.a. How big is this problem? Extent ofCondition/Causea.k.a. How big is this problem?
3 Extent of ConditionTransportability of condition - determine whether the same problem/condition exists elsewhere.Is the extent to which the condition may exist in other plant equipment, organizations, processes, or human performance.Objective .018
4 Why Perform an Extent of Condition Review? To identify down stream effects from the initial event.To identify possible event initiators and correct them prior to causing an additional event.
5 Extent of CauseTransportability of cause - determine whether the same root or underlying causes of the problem/condition may be affecting performance elsewhere (other plant processes, equipment, or human performance).Objective .018
6 Why Perform an Extent of Cause Review? To identify other places where this cause exists and correct them prior to causing an additional event.
7 The Problem Extent of Cause/Condition review too narrow. Extent of Cause/Condition review too broad.Extent of Cause/Condition review just right but is criticized as being too broad/narrow.Extent of Cause/Condition review assesses the wrong areas.
8 The SolutionA Risk Based Approach to Setting Extent of Condition/Cause Assessment Scope
9 Risk Based Three Step Approach First, define other potential instances of the same/similar condition/cause(s).Second, determine the risk of a similar event occurring with the same/similar condition/cause(s) by assigning a probability of occurrence and level of consequence if no corrective or preventive actions are taken.Third, decide if action is required.Objective .018
10 Define Potential Same/Similar Conditions Restate the event / problem and critical setup conditionsDefine Same/Similar using the following criteria.–Same - SameSame Program [e.g., CAP] or Process [e.g., Surveillance Scheduling] or System [Auxiliary Steam] with the Same kind of problem/error/failure or defect. Same Object – Same Defect–Same - SimilarSame Program [e.g., CAP vs. Self-Assessment] or Process [e.g., Surveillance Scheduling vs. 13-Week Scheduling] or System [Auxiliary Steam vs. Heater Drains] with a Similar kind of problem/error/failure or defect. Same Object – Similar Defect–Similar - SimilarSimilar Program [e.g., CAP vs. Self-Assessment vs. Management Oversight] or Process [e.g., Surveillance Scheduling vs. 13-Week Scheduling vs. WM] or System [Auxiliary Steam vs. Heater Drains vs. Main Steam] with a Similar kind of problem/error/failure or defect. Similar Object – Similar DefectObjective .018
11 Define Potential Same/Similar Causes Restate the problem statement and identified cause.(Typically just the Root Cause or principal Apparent Cause)Define Same/Similar using the following criteria.–Same - SameSame Same Same Cause – Same Impacts–Same - SimilarSame Similar Same Cause – Similar Impact–Similar - SimilarSimilar Similar Similar Cause – Similar ImpactObjective .018
12 Set the Scope of the Assessment Using the defined Same/Similar conditions/ cause(s):Determine the consequences for each defined potential condition/cause.Evaluate the chance of occurrence for each defined potential condition/cause.Identify the Risk for each defined potential condition/cause.Bound the Extent of Condition evaluation based on the defined risk. (e.g. No Risk = No evaluation)
13 Material Problems with the New Roof Nails inTiresConsequenceOther ForeignMaterial Problems with the New RoofRoofing NailsIn DrivewayRoofing NailsIn Other PlacesSame - SameSame - SimilarSimilar - SimilarObjective .018Roofer ForeignMaterial Mgt.Extent of cause Same - Same360 Degree Approach to Extent of Condition/Cause
20 Example ProblemA few gallons of hydrazine contaminated with sodium hydroxide waste was pumped from the secondary hydrazine addition tank to the Auxiliary Feedwater Storage Tank, which was being used to feed the Steam Generators while the plant was in Hot Standby.Objective .018
27 Risk Based Approach to Setting Extent of Condition/Cause Assessment Scope Value-Added Provides standardized approach for setting extent of condition/cause assessment scope.Makes thinking visible.Simplifies identifying appropriate corrective actions.
28 Questions??? Steve Davis Steve.email@example.com Objective .019Problem:The Startup rate and Intermediate rate nuclear instruments were rendered unavailable when terminal voltage on batteries B and D unexpectedly fell below the minimum allowed voltage of 21 VDC during the performance of scheduled battery charger maintenance. The event resulted in an equipment damage near miss.Setup Conditions:During previous planned maintenance, the opposite train batteries were operated beyond their design basis limit.During the planned maintenance activity, monitoring of battery terminal voltage when the chargers were turned off was only performed during the day shift, not during the night shift.Key individuals had a knowledge deficiency as to how battery voltage would decayAn identified battery monitoring deficiency with the battery operating procedure was not correctedSame – SameScope:Batteries A, B, C, D, Other compensatory measures with Battery A, B, C, D planned maintenance. Battery A, B, C, D operating procedure.QuestionsWhere else do we have the potential for an unexpected battery condition (operating beyond design, low/high voltage, etc,) during battery charger maintenance on Batteries A, B, C, and D due to inadequate compensatory measures?Are there other monitoring deficiencies in battery A, B, C, D operating procedure?Same – SimilarOther Station Batteries, both safety related and non-safety related.Licensed Operators, Electrical Maintenance, Planners, System Engineer.Other battery operating proceduresQuestions:Where else do we have the potential for an unexpected battery condition (operating beyond design, low/high voltage, etc,) during battery charger maintenance on other station batteries due to inadequate compensatory measures?Are there other deficiencies with the battery operating procedure?What other battery knowledge deficiencies exist with key station personnel?Similar – SimilarAll planned maintenance packages that require compensatory measuresOther station personnel that have oversight for battery operation or maintenanceOther procedures that contain battery operating instructionsWhat other planned maintenance activities have the potential result in an unexpected condition because of inadequate compensatory measures?What other station personnel have battery knowledge deficiency.What other station operating procedures have that contain battery instructions have deficiencies?ProblemRoot Cause(s)High work control performance standards and practices have not been enforced by ensuring procedures and work practices meet the station’s needs, and are used.Work control process (planning, package development, scheduling, reviews, approvals, etc.).None, the root cause statement covers the entire work control process.Other work processes that may affect plant equipment.Question:Is the station enforcing high performance standards in the projects and modification process? Projects and modifications both affect installed plant equipment.Other station program/processesWhere at the station is the management team not enforcing high program/process performance standards (e.g., Training, Safety, Radiation Protection)?Steve DavisChet Rowe
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