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Work In Progress – P497
January 29, 2014 (NPEC 14-01) By Greg M Hostetter (WG-6.1 Chair)
“Standard Criteria for Accident Monitoring Instrumentation for
Nuclear Power Generating Stations”
Work In Progress – P497 Presentation Contents
1. P497 PAR Summary 2. Working Group Membership 3. P497 Table of Contents 4. Summary of Changes to Date 5. Schedule 6. Conclusion
Work In Progress – P497 1. PAR Summary
PAR approved March 6, 2013; PAR expires December 31, 2017. Scope This standard contains the functional and design criteria for accident monitoring instrumentation for new plant designs and nuclear power generating stations desiring to perform design modifications. Purpose The purpose of this standard is to establish selection, design, performance, qualification and display criteria for accident monitoring instrumentation for anticipated operational occurrences, design basis events and severe accidents.
Work In Progress – P497 1. PAR Summary (continued)
Need for the Project: 1. Address lessons learned from industry events (Fukushima [earthquake
& tsunami], Browns Ferry [tornado / hurricane], Salem [loss of RPS due to CCF], North Anna [seismic event], etc.).
2. Address accident monitoring instrumentation requirements based emergency procedure guidelines (including Severe Accident Management Guidelines) and monitoring of fission product barriers and plant conditions following a potential breach of these barriers.
3. Continue advancing the standard to a technology neutral approach (including small modular reactors) and improve international usability.
4. Incorporate user feedback. 5. Provide requirements for instrumentation used during severe accident
conditions. 6. Revise the standard as a joint project with IEC, making the standard a
joint-logo standard.
Work In Progress – P497 1. PAR Summary (continued)
Additional Explanatory Note: This standard will address only the Severe Accident subset of Beyond Design Basis Events that directly affect the core fuel, and does not address Beyond Design Basis external events such Loss of Large Area (LOLA) events.
Work In Progress – P497 2. Working Group Membership
O Formed following issuance of 497-2010 O 14 Full members (2 corresponding Members)
Michiaki Akiyama Jason Karns Jeri Chadwick Alex Klemptner Alexander Duchac Wolfgang Koenig Daryl Harmon (VC) Rie Nakamura Greg Hostetter (C) Ifti Rana Takeshi Ikeuchi Yumi Sato Gary Johnson Steve Wyman Glen Lang (CM) Barry Marcus (CM)
Owner (1), NSSS (6), AE/Consultant (7), Regulator (2)
US Members (11), International Members (5)
New members continuing to join each meeting
Work In Progress – P497 3. P497 Table of Contents
1. Overview 2. Normative References 3. Definitions 4. Selection Criteria (added clause for Type F Variables) 5. Performance Criteria 6. Design Criteria 7. Qualification Criteria (added clause for Type F Variables) 8. Display Criteria 9. Quality Assurance Annex A (informative): Accident Monitoring Instrument Channel Accuracy Annex B (informative): Examples of Monitoring Channel Displays Annex C (informative): Bibliography
Work In Progress – P497 4. Summary of Changes to Date
O Added Type F Variable O Selection Criteria (Clause 4.6)
O Provide primary information to accident management personnel to indicate fuel damage and the effects of fuel damage. Source Documents
O SAMGs O Severe Accident Analysis
Work In Progress – P497 4. Summary of Changes to Date
O Added Type F Variable (cont.) O Range (Clause 5.1)
O Extended ranges to encompass fuel damage
O Address a source term that considers fuel damage.
O Operating Time (Clause 5.4) O Sufficient to implement mitigation guidance based on
the longest duration analyzed severe accident event
O At a minimum, equal to or longer than the duration for the longest design basis event that may precede event.
Work In Progress – P497 4. Summary of Changes to Date
O Added Type F Variable (cont.) O Power Supply (Clause 6.6)
O Separate stand-alone power supply shall be available.
O Stand-alone power supply shall be in addition to and independent from Class 1E or normal non-Class 1E power supplies.
Work In Progress – P497 4. Summary of Changes to Date
O Added Type F Variable (cont.) O Qualification Criteria (Clause 7.6)
O Instrument channels shall be type tested to the anticipated severe accident environmental conditions. If anticipated environmental conditions are not reached and a failure is not experienced, then a survivability analysis shall be performed for the anticipated severe accident environments. The survivability analysis determines constraints for reliable use.
O Qualified Operating Time (Clause 7.8) O May be shorter than the length of time required.
Shorter operating times shall be documented to determine the constraints for the reliable use.
Work In Progress – P497 4. Summary of Changes to Date
O Added Type F Variable (cont.) O Trend or Rate Information (Clause 8.2)
O Capability of providing at least enough data to determine trend or rate information.
O Display Identification (Clause 8.3)
O Uniquely identify severe accident variables.
O Display Location (Clause 8.5) O Be displayed in locations used for command and control.
O Recording (Clause 8.7) O Sufficient to implement the SAMGs O At a minimum as long as the operating time
Work In Progress – P497 4. Summary of Changes to Date
O Moved to IAEA definitions when appropriate
O Adjusted definitions when needed (functionally the same with adjustment of the wording) O analog sensor: The portion of a channel that responds to changes in a plant
variable or condition and converts the measured process variable into a corresponding value.
O anticipated operational occurrence (AOO): An operational process deviating from normal operation which is expected to occur at least once during the operating lifetime of a facility but which, in view of appropriate design provisions, does not cause any significant damage to items important to safety or lead to accident conditions.
O common cause failure: Failure of two or more structures, systems, or components due to a single event or cause.
Work In Progress – P497 4. Summary of Changes to Date
O Adjusted definitions when needed (cont.) O response time: Duration between the instant of a step change in the measured
quantity and the instant when the output signal reaches for the first time a specified percentage of its final value, that percentage being usually taken as 90%.
O safe shutdown: Bringing the nuclear generating station to controlled stable shutdown conditions specified in licensing basis documentation.
O Added new definitions to clarify meanings of terms in the standard O accident management personnel: The personnel authorized to make
command and control decisions during an accident.
O instrument channel range: The region between the limits within which a quantity is measured, received, or transmitted and is expressed by stating the lower and upper instrument channel range value.
O isolation device: Device in a circuit that prevents malfunctions in one section of a circuit from causing unacceptable influences in other sections of the circuit or other circuits.
Work In Progress – P497 5. Schedule
O Preview to NPEC: January 2015 O Submit to IEC for consideration: February 2015 O Complete ballot pool: March 2015 O Initial sponsor ballot: April 2015 O Resolve ballot comments: July 2015 O Submittal to RevCom: October 2015 O Publish: December 2015
O PAR Expiration: December 2017
Work In Progress – P497 6. Conclusions
O P497 is progressing as scheduled.
O Severe accident instrumentation is now being addressed in the standard following an approach based on instrument needs to implement SAMGs without the intention to force new instruments if not necessary.
O Standard is continuing to become less US centric and more global as the standard moves toward a future joint logo standard.
