Research on Integration of NPP Operational Safety Management Performance Systems

Transcription

1 Research on Integration of NPP Operatioanl Safety Management Performance System Research on Integration of NPP Operational Safety Management Performance Systems Miao CHI 1, Liping SHI 2 1. School of Economics & Management, Harbin Engineering University, , P.R.China ( chimiao@hrbeu.edu.cn) 2. School of Economics & Management, Harbin Engineering University, , P.R.China ( chimiao@hrbeu.edu.cn) 1 Introduction Abstract: The operational safety management of Nuclear Power Plants demands systematic planning and integrated control. NPPs are following the well-developed safety indicator proposed by Operational Safety Performance Indicator Programme, Reactor Oversight Process or the other institutions. Integration of the is proposed to benefiting from the advantages of both and avoiding improper application into the real world. The authors analyzed the possibility and necessity for system integration, and propose an indicator system integrating method. Keyword: Operational safety management, Performance system, Integration The safe operation of all nuclear power plants is a common goal for all involved in the nuclear industry. A high level of safety is the result of the complex interaction of good design,operational safety and human. As diversified backgrounds and utilities, NPPs and regulators selected a set of indicators, which is diversified and mainly lagging in nature, with reference to the practices of other utilities that operate the same type of plants. Although the improvement of core technologies, yet NPP is suffering from low safety operation management efficiency, and the public complaining is increasing because the complicated safety statistics is hard to be compared or understood which follow different standards. At the post-fukushima incident, it is crucial for NPP operators and regulators to adopt a standardized and integrated indicator system in order to improve NPP safety management. best interests of reactor safety. The effectiveness of plant management in promoting the use of indicators as a tool for improvement is vital to the success of any operational safety monitoring programme. This paper compared the two most popularly adopted safety indicator -operational safety indicators for nuclear power plants (-TECDOC-1141) [2], with regulatory oversight (10 CFR Part 50) [3], in order to identify the main differences and correlations between the safety indicator proposed by and. An integrated indicator system is proposed as a solution for low efficiency caused by diversified indicator, and the necessities and possibilities of integrate indicator are then suggested. The authors studied the correlation between the objectives and attributes and established a Weight Identification Model. Integration Graph Analysis Method was applied to identify the difference degrees and degrees. With the aid of Integration Matrix, the authors suggested indicator integration categories, i.e. integration in priority, maintaining, and integration after. When properly used, indicators are a valuable tool for operating nuclear power plants safely. When used improperly, undue pressure may be applied to plant personnel resulting in management or manipulation of the indicators, rather than assessment. [1] In fact, improper use of operational safety 2 Systems Used in the Comparison indicators can result in actions that are not in the Safety indicator - operational ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,

2 Miao CHI, Liping SHI safety indicators for nuclear power plants (-TECDOC-1141), and (10 CFR Part 50), are the two indicator most popularly adopted by NPPs. Table 1 presents the basic profiles of the two. Table 1 Comparison between Operational Safety Performance Indicators for Nuclear Power Plants and Regulatory Oversight [2]\[3] Objectives Operational safety indicators for nuclear power plants. To monitor nuclear power plant operational safety. Reactor Oversight Process by the US Nuclear Regulatory Commission. To ensure adequate protection of public health and safety. Approach A hierarchical and risk-based approach. A risk-informed approach. Function Principles Structure Attributes of appropriate indicators Accommodating several applications, including the identification and correlation of potential event forerunners that could signal deterioration in future safety. A framework for identification of indicators which have a relationship to the desired safety attributes, and therefore to safe plant operation. Using the attributes as a starting point for indicator development, a set of operational safety indicators were identified.below each attribute, overall indicators were established. Associated with each overall indicator is a level of strategic indicators. Each strategic indicator is supported by as et of specific indicators, most of which are already in use in the industry. Indicators were developed on elevelatatime to ensure that all relevant safety aspects of each attribute were covered. There is a direct relationship between the indicator and safety; The necessary data are available or capable of being generated; Indicators can be expressed in quantitative terms; Indicators are unambiguous; Their significance is understood; They are not susceptible to manipulation; They are a manageable set; They are meaningful; They can be integrated into normal operational activities; They can be validated; They can be linked to the cause of a malfunction; The accuracy of the data at each level can be subjected to quality control and verification; Local actions can be taken on the basis of indicators. Maintain safety; Increase openness; Make activities and decisions more effective, efficient, and realistic; Reduce unnecessary regulatory burden. Intergrated risk-informed decision making: Current regulations are met; Defense-in-depth consistency; Maintenance of safety margins; Risk-informed anaysis; Performance moninoring. The staff used a top-down, hierarchical approach to develop the concept for a new regulatory oversight framework that addresses the agency s regulatory principles. This approach started with a desired outcome, identified goals to achieve this outcome, and then identified specific objectives and information needs to meet each goal. A direct relationship should exist between the indicator and safety expectations; Data necessary to measure the indicator should be available or capable of being generated; Indicators should be capable of being expressed in quantitative terms that are not ambiguous; Indictors should be meaningful, i.e., their significance is readily understood; Indicators should be able to be validated. Program implementat ion should Assist NPPs in developing and implementing a monitoring programme, without overlooking the critical aspects related to operational safety. 2.1 Feasibility for Integration Both and encourage enrichment of the safety indicator. Plants may choose to consider additions to the proposed framework as needs dictate. [4] Reactor Oversight Provide clear roles and responsibilities of the and licensees; Communicate results to the public; Include a decision model or criteria so that actions are predictable; Be simple, non redundant, and resource efficient. Process Basis Document, Manual Chapter 0308, Inspection Manual,, August 2011Where possible, these indicators have been proposed as specific indicators, as they are already in use and require no additional effort on the part of nuclear plant personnel. [5] oversight is consistent with the goal of continued improvements in plant 2 ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28, 2014

3 Please write title of the paper here 3 safety and reliability through a more focused, objective and efficient regulatory process. [6] indicator system and regulatory oversight share correlation in the following areas [7]- [10] : (1) Two share similar philosophies of risk informed, based, process management and process control. (2) Both intend to standardize management behavior and improve management. (3) Both adopt similar principles, i.e. defence-in-depth consistency, maintenance of safety margins, risk-informed analysis, monitoring. (4) Both adopt a top-down, hierarchical approach which started with a desired outcome, identified goals to achieve this outcome and then identified specific objectives and information needs to meet each goal. (5) and have different focuses on indicator, i.e. focuses NPP improvement which includes both safety and economic indicators; reactor oversight process serves the mission of public health and safety. However, the two will enrich each other. 2.2 Necessity for Integration Management and management system is defined as an activity or process, which consists of many sub-. The propelling power in a system depends on mutual influence, and interaction. Integrating correlated contribute to integrated decision, resource allocation at high efficiency, and improvement of overall. The internationally agreed programme is continuously reviewed and further developed to allow individual plants to compare their more easily with industry average [11] values. It is expected that the use of standardized indicators will encourage emulation of the best industry. It should also further motivate the identification and exchange of good practices in nuclear power plants operations. Indicator system integration will contribute to standardization of indicators of NPPs, which enhances openness of NPP operation and help communication with the public and the other stakeholders. [12] The internationally agreed programme is continuously reviewed and further developed to allow individual plants to compare their more easily with industry average [11] values. It is expected that the use of standardized indicators will encourage emulation of the best industry. It should also further motivate the identification and exchange of good practices in nuclear power plant operations. Indicator system integration will contribute to standardization of indicators of NPPs, which enhances openness of NPP operation and help communication with the public and the other stakeholders. [12] 3 System Integration Process Literature suggests some system integration methods, e.g. Element Comparing Method, New Technology Integration Method, and Hierarchial Integration Method. However, operators and regulators complained that those methods were not applicable into the real world as they did not consider key attributes of the or resource availability. Thus this paper proposed the NPP Operation Indicator System Integration Process. [13] 3.1 Indicator System Comparison The authors suggest following the main framework of indicator system as indicator system provides a broader coverage of indicators. A comparative indicator system including comparable indicator areas (Appendix) are suggested. 3.2 Attribute Relevance Model and Attribute Weights Both are influenced by a series of attributes and factors, and system integration demands attributes integration. The authors develop an Attribute Relevance Model (Table 2), which consists resources attributes, i.e. human (human and human errors), safety conscious environment (design and equipment ), and problem identification (procedure quality and configuration control); and safety system attributes, i.e. management elements, functions, for observation, key attributes measured, indicators for ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,

4 Miao CHI, Liping SHI observation, caculational method and thresholds & basis. Based on one NPP operational status, experts were invited to comment the relevance degrees (highly relevant, relevant and irrelevant) on each resource & system matching pair. Comparative weights were concluded based on the analysis of the comments. Table 2 Attribute Relevance Model [3] Management Elements Functions Systems Key Attributes Measured Indicators for Caculational Observation Method Thresholds &Basis Human Performance Human Performance HR* HR HR HR HR HR HR Human Errors HR HR HR HR HR HR HR Safety Conscious Environment Design R* R HR HR HR HR HR Equipment Performance R HR HR HR HR HR HR Problem Identification & Resolution Programs Highly Relevant Procedure Quality Configuration Control HR HR HR HR HR R R HR HR HR HR HR I* I Relevant Irrelevant Total Score Attribute Weight Rounding Weight *HR: highly relevant, R: relevant, I: Irrelevant 3.3 System Difference and System Adjustment Possibility The authors propose System Difference Function and System Adjustment Function [13] : System Difference(D):(Management Elementsx0.13)+(Functionsx0.15)+(Systemsx0.16) +(Key Attributes Measuredx0.16)+(Indicators for Observationx0.16)+(Caculational Methodx0.12)+(Thresholds &Basisx0.12) System Adjustment Possibility (A): (Management Elementsx0.13)+(Functionsx0.15)+(Systemsx0.160 )+(Key Attributes Measuredx0.16)+(Indicators for Observationx0.16)+(Caculational Methodx0.12)+(Thresholds &Basisx0.12) difference function and system function, the authors calculated the difference status and possibilities of each pair of comparative indicator areas (Appendix). 3.4 Integration Matrix The authors developed an integration matrix with difference status as Axis, possibilities as Axis X. A graph can be obtained based on the scores of difference and. According to the quadrant of the point, the possibility for integration will be identified (Fig. 1) [13] Experts were invited to give comment matrix on System Difference and System Adjustment Possibility bands (Table 3 & 4). With system 4 ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28, 2014

5 Research on Integration of NPP Operatioanl Safety Management Performance System Table 3 System Difference Degree Bands Mgt. Elements Functions Systems for Observation Key Attributes Measured Indicators for Observation Caculational Method Thresholds & Basis 4 Seldom Similar 4 Seldom Similar 4 Seldom Similar 4 Seldom Similar 4 Seldom Similar 4 Seldom Similar 4 Seldom Similar 3 50% Similar 3 50% Similar 3 50% Similar 3 50% Similar 3 50% Similar 3 50% Similar 3 50% Similar 2 focus 2 Mostly Similar 2 Mostly Similar 2 Mostly Similar 2 Mostly Similar 2 Mostly Similar 2 Mostly Similar 1 Same 1 Same 1 Same 1 Same 1 Same 1 Same 1 Same Table 4 System Adjustment Possbility Bands Mgt. Elements Functions Systems for Observation Key Attributes Measured Indicators for Observation Caculational Method Thresholds & Basis work 4 A little 4 A little 4 Examine more 4 Add attributes 4 Add indicators 4 Share similarities 4 Share similarities 3 Demand great effort for 3 Achieve partial similarity after 3 Achieve partial similarity after 3 Some attributes need to be adjusted 3 Some indicators need to be adjusted 3 Demand great effort for 3 Demand great effort for 2 Demand focus 2 Invest more resources to achieve 2 Invest more resources to achieve 2 The majority of attributes need to be adjusted 2 The majority of indicators need to be adjusted 2 Integrate after indicator integration 2 Integrate after indicator integration Fig. 1 Integration Matrix ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,

6 Miao CHI, Liping SHI 3.5 Findings The Integration Matrix demonstrates that: 1. The point (Significant Incidents due to Hardware/design related Causes vs. EP Facility and/or Equipment Status) (D: 3.17, A:4.16) and the point (Reportable Events vs 14-day Reporting Requirement for PI Data) (D:3.73, A:4) fall into the second quadrant, which show obvious difference and demand pretty efforts for integration. Fig. 1 Integration Matrix The indicator (Reportable Events) demands collecting event data and focus on examining regulation on safety significance, while 14-day reporting requirement for PI data stress detecting improper regulation on requirements. However, the two indicators both contribute to event reports and indicator will help to broaden s scope. indicator (Significant Incidents due to Hardware/design related Cause) and indicator (EP Facility and/or Equipment Status) examine equipment status but with different focuses. focus on significant incidents while watches a broader range. The authors suggest adjusting range according to some helpful indication from. The need broaden the current range and adjust the tools for examination. 2. The point (Corrective Work Orders Issued vs. EP Corrective Actions Completed on Time)(A:2.95, D:3.21) falls into the fist quadrant, which is essentially stressing different aspects or demand different resources. indicators (Corrective Work Orders Issued) stress work orders, while indicators (EP Corrective Actions Completed on Time) focus on the response in emergency preparedness. As has indicators related to emergency preparedness, corrective work orders issued is suggested to maintain as it is. 3. The remaining points fall into the fourth quadrant, which share similarities in the major attributes and enjoy priority for integration. Operators or regulators only need add the indicator attributes of into the indicator of. 4 Conclusions This paper compared the two most popularly adopted safety indicator -operational safety indicators for nuclear power plants (-TECDOC-1141), with regulatory oversight (10 CFR Part 50), to identify the main differences and correlations between the safety indicator. The authors proposed NPP Operational Safety Management Performance Systems Integration method. The method provides a solution for operators and regulators to optimize an indicator system based on a specific NPP case. The method does not demand complicated computation but suggest comprehensive consideration from the perspectives of resouces, system attributes and NPP operational status. However, the method relies on experts comments which extend high requirements of experts selection and experts experience in NPP operation. The integration method is also an effective tool to identify the crucial factors influencing the NPP safety operation, and help to analyze and evaluate indicator. For further studies on specific indicator need to be performed on the insights and findings suggested by Integration Matrix References [1] Operational safety indicators for nuclear power plants,, VIENNA, Austria, May 2000:24. [2] Operational Safety Performance Indicators for Nuclear Power Plants, TECDOC 1411,, Austria, May 2000 [3] Reactor Oversight Process Basis Document, Manual Chapter 0308, Inspection Manual,, August 2011 [4] Operational Safety Performance Indicators for Nuclear Power Plants, TECDOC 1411,, Austria, May 2000: 5 [5] Nuclear Energy Agency Committee on the Safety of Nuclear Installations, NEA/CSNI/R (2002)2, OECD, May 2002:12 [6] WANO Performance Indicator Programme, NEA/CSNI/R(2001), WANO, 2001:344 [7] WANO Performance indicators, INDICATORS TO MONITOR NPP OPERATIONAL SAFET PERFORMANCE, proceeding [8] Regulatory Assessment Performance Indicator Guideline, NEI 99-02[Revision 7], [9] Nuclear Energy Institute, 2013 [10] Trending of Low Level Events and Near Misses to Enhance Safety Performance in [10] Nuclear Power Plants,, 2005 [11] Indicators for Management of Planned Outages in Nuclear Power Plants [12] Reactor Oversight Process Basis Document, Manual Chapter 0308, Inspection Manual,, August 2011 [13] Reactor Oversight Process Basis Document, Manual Chapter 0308, Inspection Manual,, August 2011 [14] Zhyong, Jingui, Study on Integration Management System (IMS) Approaches and Programme, Donghua University Doctoral Dissertation, ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28, 2014

7 Research on Integration of NPP Operatioanl Safety Management Performance System Appendix: System Difference & Adjustment Score Matrix System Content Mgt. Elements Functions Systems for Observation Key Attributes Measured Indicators for Observation Caculational Method Thresholds & Basis Overall Value No. of forced power reductions and outages due to internal causes Forced power reductions and outages Operating Challenged safety functions Power system Human error, procedure quality, design, and equipment No. of forced power reductions and outages due to external causes Unit capability factor WANO WANO Unplanned capability loss factor WANO WANO Unplanned power changes per 7000 critical Hours Power changes Challenged safety functions,indi cation of risk-significant events Power system Human error, procedure quality, design, and equipment Number of unplanned power changes,total number of hours critical D A No. of corrective work orders issued for safety Corrective work orders issued SSC Work orders, Systems reliability Maintenance program, safety related Human, procedure quality, equipment No. of corrective work orders issued for risk-important BOP (Balance Of Plant) programmed No. of pending work orders for more than 3 months EP corrective actions completed on time (not used) Safety related Systems reliability Emergency preparedness Human, procedure quality, equipment - D A State of the barriers Material Barriers: cladding, RCS Design control, configuration control, Fuel reliability WANO WANO ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,

8 Miao CHI, Liping SHI primary coolant boundary, containment cladding, procedure quality, and human RCS (reactor coolant system) leakage Containment leakage Barrier integrity SSC Integrity of the RCS pressure boundary, RCS Identified Leakage, RCS integrity. RCS Design control, configuration control, cladding, procedure quality, and human RCS equipment & barrier BI01 Reactor coolant system (RCS) specific activity BI02 RCS iidentified leak rate Containment leakage (not used) D A Reportable events Events Safety significance, data, regulation Data reporting Procedure quality, human error, equipment Significant reportable events Licensee event reports 14-day reporting requirement for PI data(not used) Requirement Industry comment and feedback Requirement Procedure quality, human error, equipment - D A Significant incidents due to hardware/design related causes Significant incidents Incidents Hardware Design control, human error, equipment -Incidents, EP facility and/or equipment status (not used) Equipment status Equipment status Facility/Equipmen t Design control, human error, equipment - D A Actual challenges Challenges to safety Reactivity control safety function, the control of inventory, core cooling safety functions The that support the reactivity control safety function, inventory and core cooling safety functions, safety Human error, procedure quality, design, equipment, configuration control, human Unplanned automatic scrams per 7000 hours critical WANO WANO 8 ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28, 2014

9 related power supply No. or demands on RPS (reactor protection system), no. or demands on ECCS (emergency core cooling ),no. or demands on RHR(residual heat removal), no. or demands on electric power supply Please write title of the paper here 9 Mitigating Safety Safety functions in response to off-normal events or accidents Important safety Human error, procedure quality, design, equipment, configuration control, human No. of demands on other Safety Systems IE01 Unplanned scrams per 7000 critical hours MS08 Mitigating system index (heat removal ) IE04 Unplanned scrams with complications MS09 Mitigating system index (residual heat removal ) MS06 Mitigating system index (emergency AC power ) D A Potential challenges Mitigating Challenges to safety system Low level events, warning function Safety functions, reliability of System Safety, Important safety events or conditions Offsite alert and notification system (ANS), testing program Configuration control, equipment,human Configuration control, equipment,human Facilities and equipment No. of RPS (reactor protection system) /ESFAS (engineered safety features actuation system) failures No. of failures in safety Safety system WANO WANO Percentage of failures discovered by surveillance and testing MS10 Mitigating system index (cooling water ) MS07 Mitigating system index (high pressure injection S) MS05 Safety system functional Failures Safety system actuation (not used) EP03 Alert and notification system reliability D A Emergency Plant ability Emergency Plant ability to Facilities and equipment, Findings during emergency drills ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,

10 Miao CHI, Liping SHI preparedness Emergency preparedness to respond to a challenge management Licensee in drills and exercises, emergency response organization (ERO) respond to the challenges Drills and exercises, emergency response organization (ERO) members procedure quality, and emergency response organization (ERO) Facilities and equipment, procedure quality, and emergency response organization (ERO) Findings during emergency plan audits Number of hours devoted to training on the emergency plan No. of staff receiving training on the emergency plan EP01 Drill/exercise ERO Activation tests (not used) EP Drill objectives met (not used) EP Training conducted (not used) EP02 ERO drill participation D III A Radiation protection programme effectiveness Occupational radiation safety,public radiation safety Radiation protection programme, administrative control, safety culture Readily-identifi able unintended dose, Performance of the radiological effluent control program Sources of radiation, protective barriers,protective equipment, contamination radiologically-sig nificant areas, safety barriers, Radiological effluent control program Plant facilities, equipment & instrumentation, program, process, and human. Plant facilities, equipment & instrumentation, program, process, and human Percentage of controlled area that is contaminated Effluent activity vs. allowed limit OR01 Occupational exposure control effectiveness PR01 RETS/ODCM Radiological effluent occurrence D A ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28, 2014

11 Research on Integration of NPP Operatioanl Safety Management Performance System ISOFIC/ISSNP 2014, Jeju, Korea, August 24~28,