Online Calibration Monitoring of Process Instruments in NPPs Halden, 27 September, 2004

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On-line Calibration Monitoring of Process
Instruments in NPPsHalden, 27 September, 2004
Presented by Janos Eiler, Paks Nuclear Power
Plant Ltd.
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TWG - NPP CI Activities
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What is a TECDOC?

• Managing Modernization of Nuclear Power Plant
  Instrumentation and Control Systems
• Perception of needs for IC modernization
• Project preparation and feasibility study
• Modernization project implementation
• Questionnaire for IC modernization projects

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Overall Scheduleof Activities

• 2003 TWG NPPCI meeting suggested this new TECDOC
• The TWG believes on-line monitoring is one of the
  most promising areas for IC development
• (The current practice usually calls for
  calibration verification of almost all
  instruments every fuel cycle, regardless of their
  calibration status)

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Overall Scheduleof Activities

• 2003 TWG NPPCI meeting suggested this new TECDOC
• 1st Consultants meeting, 15-18 March, 2004,
  Vienna
• 2nd Technical meeting, 27-29 September, 2004,
  Halden
• 3rd Consultants meeting, Spring 2005, (Vienna or
  Soul?)
• Expected publication Late 2005

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Objectives of Condition-Based Calibration (CBC)

• Develop new technologies for identifying drifting
  instruments as a means of determining if and when
  a transmitter or a loop must be calibrated
• Implementing these technologies allows
  calibration efforts to be focused on the
  instruments that have drifted out of tolerance
• Save calibration costs, reduce personnel
  radiation exposure, and add to plant safety and
  reliability

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Principle of Condition-Based Calibration

• Determine if calibration is needed.
• Track the output of instrument channels over the
  fuel cycle
• Identify drift, bias errors, noise and other
  anomalies
• Advantages
• it identifies calibration problems as they occur,
  
• accounts for installation and process condition
  effects on calibration, and
• includes most components of an instrument channel
  in the calibration test as opposed to the
  conventional procedures, which require some
  components to be isolated and calibrated
  individually
• prevents unnecessary calibration of instruments
  that have maintained their calibrations
• Calibrate if needed.

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TECDOC coverage

• Instrument calibration reduction or increasing
  the calibration intervals of process instruments
  such as
• pressure, level, and flow,
• temperature
• neutron flux transmitters
• and entire instrument channels
• Economic and safety benefits
• Regulatory approval process
• Quality Assurance (QA) requirements
• (This is the first of a series of TECDOCs)

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Related Documents

• NUREG/CR-6343, On-Line Testing of Calibration of
  Process Instrumentation Channels in Nuclear Power
  Plants, 1995
• EPRI TR-104965-R1 NRC SER, On-Line Monitoring of
  Instrument Channel Performance, 2000
• American National Standard, ANSI/ISA-67.06.01-2002
  , Performance Monitoring for Nuclear Safety
  Related Instrument Channels in Nuclear Power
  Plants. 2002

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Related TECDOCunder printing

• Plant Life Cycle and Aging Management Using
  Improved IC Maintenance
• Relationship between IC aging, life cycle
  management and maintenance
• Ageing and obsolesce process
• Cable ageing managements
• Role of IC in plant performance improvements
• Relation with IEC SC 45 A
• Publication in the middle of 2004

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Overview of traditional calibrations

• The nuclear power industry currently practices a
  very conservative approach
• Daily Channel Checks
• Surveillance Tests (sensor is not tested)
• Full-Channel Calibration
• Response Time Testing

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Application of the Channel Test Card
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Schematic of a Typical Redundant Instrument Set
Channel Test Card
Master Test Card
Resistance to Voltage Converter
Summing Amplifier



1
2






3
?T
Relay Test Card
Relay Test Card
Summing Amplifier
Lead Lag
Lead Lag
ISO



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Lessons learned from current calibrations

• Searches of the License Event Report (LER) and
  Nuclear Plant Reliability Data System (NPRDS)
  databases show that less than three percent of
  pressure transmitters have drifted out of
  tolerance.
• This amounts to about 2.8 failures per plant per
  fuel cycle from the NPRDS database and 0.66
  failures per plant per fuel cycle from the LER
  database assuming 100 reactors and two-year fuel
  cycles.
• This can provide substantial cost savings to
  utilities including direct reductions in labor,
  personnel radiation exposure, and material and
  indirect savings from increased instrument
  reliability and plant safety, simplified outage
  planning and scheduling.

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Results of Search of LER
Number of LERs on Failures of Pressure
Transmitters during 1980-1992 (1886)
391 cases of calibration problems at over 100
nuclear power plants in 12 years.
Personnel Error 587 (31)
Age-Related Problems 662 (36)
Other Causes 617 (33)
Calibration Drift 391 (59)
Flow Blockage 106 (16)
Fatigue / Vibration /Corrosion 165 (25)
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Implementation of CBC(not yet elaborated)

• Exactly how do we collect data, or what data do
  we use for CBC in real plant applications?
• Where (in what system) do we run CBC? What
  additional (physical) installations are needed
  for it?
• What computer system does CBC need?
• Who is responsible for its operation and
  maintenance?
• Where (to whom) do we provide output from CBC? In
  what form?
• How and where are acceptance criteria applied?

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Related research

• EPRI
• UT
• ANL
• AMS
• HALDEN/IFE
• EDF
• AECL/OPG

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Standards and guidelines

• There are only a couple of formal documents on
  their use
• Instrumentation, Systems, and Automation (ISA)
  Society
• ISA Standard 67.06. Performance Monitoring for
  Nuclear Safety-Related Instrument Channels in
  Nuclear Power Plants., 2002 (Published by the
  American National Standard Institute under
  ANSI/ISA-67.06 01 2002 designation.)
• International Electrotechnical Commission (IEC)
• IEC 61255. It is due for publication in 2006. The
  standard is similar to ISA 67.06 mentioned above
  and covers both the dynamic and static aspects of
  instrument performance.

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Data acquisition foron-line monitoring

• Requirements for Data Acquisition
• Portable Data Acquisition Systems
• Synchronized sampling of portable data
  acquisition systems
• Resolutions, continuous recording, data storage
• Permanently Installed Data Acquisition Systems
• Isolation Requirements for On-line Data
  Acquisition Systems
• Analog Signal Conditioning
• Required Plant Conditions for Data Acquisition
• Integration of On-line Monitoring Systems with
  Plant IC and Other Plant Computer Systems

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Data analysis foron-line monitoring

• Averaging Techniques and Consistency Checking
• Simple Average
• Weighted Average
• Band Average
• Parity Space
• Modeling Techniques
• Data-driven techniques and Neural Networks
• Fuzzy Logic
• First Principle Methods
• Estimation Methods 
• Pattern Recognition
• Other Empirical Methods
• Statistical Methods
• Uncertainty Analysis

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Acceptance criteria foron-line monitoring

• Instrument Channel Uncertainties
• CSA Band and Drift Band

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Benefits andpitfalls of CBC

• Main advantages
• reduction of manpower requirements,
• reduction of radiation exposure to maintenance
  personnel, and
• reduction of risk associated with mis-calibration
  of instruments and maintenance-induced reactor
  trips.
• checking instrument performance indicators
• Main challenges
• obtaining regulatory approval to implement
  on-line monitoring,
• uncertainties in data analysis methodologies, and
• cost of implementation

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Challenges in changing calibration strategies

• CBC is typically only performed at a single
  operating point
• difficult to establish acceptance criteria
• difficult to gain plant management acceptance
• regulatory issues
• personnel issues, jobs threatened by the
  reduction in workload
• reducing the opportunity of examining a sensors
  installation material condition

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Regulatory aspects

• The approach varies depending on the generic
  approach of the Regulator to the Licensee and
  also the CBC strategy employed.
• (USA) is a prescriptive regulator who expect
  their expectations to be complied with
• (UK) are non prescriptive and expect the utility
  to provide an acceptable justification and
  supporting evidence
• (It is necessary to consider what impact CBC
  might have on any assumptions made in the safety
  analysis for the plant. In particular, the impact
  (if any) on assumptions made about sensor drift
  and reliability.)

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Key recommendations

• Will be elaborated when the TECDOC main body is
  completed

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Examples ofBibliography items

• EPRI, Report 1003568 Collected Field Data on
  Electronic Part Failures and Aging in Nuclear
  Power Plant Instrumentation and Control (IC)
  Systems, (September 2002).
• HASHEMIAN, H.M., Verifying the Performance of
  RTDs in Nuclear Power Plants, Temperature, Its
  Measurements and Control in Science and Industry,
  AIP Conference Proceedings, Volume 7, Part 2, pp.
  1057-1062 (2002)
• International Electrotechnical Commission, IEC
  Standard, Nuclear Reactors Response Time in
  Resistance Temperature Detectors (RTDs) In-Situ
  Measurements, Rep. CEI/IEC-1224 (1993)

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Country reports

• Will be provided by the writing committee members
  and other volunteers interested in the topic

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Contributors to drafting

• Chairman
• Hash Hashemian (USA, AMS)
• Members
• Mr. Dave Lillis (UK, Sizewell B NPP),
• Mr. Janos Eiler, (Hungary, Paks NPP)
• Mr. Hee Wan Ju (Rep. of Korea KHNP)
• Mr. Oivind Berg (Norway, IFE)
• Mr. Oszvald Glöckler (Canada, OPG)
• (Mr. Ki-Sig Kang, IAEA NPES)

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Thank you for your attention!