International Electrotechnical Commission (IEC) 60780 Nuclear power plants Electrical equipment of the safety system Qualification Richard T. Wood Oak Ridge National Laboratory presented at IEEE Subcommittee 2.0 Meeting Clearwater Beach, Florida November 5, 2007 1
IEC Has Initiated Work Project For Revision of IEC 60780 IEC 60780, Rev. 2, was issued in 1998 IEC Technical Committee 45, Subcommittee 45A, Working Group 9A has responsibility for maintaining IEC 60780 Following Subcommittee 45A recommendation from Lyon 2006 meeting, revision of IEC 60780 was authorized Principal technical issue involves inclusion of condition-based monitoring guidance Administrative goal is to enhance harmonization of international standards 2
Shows Notable Consistency IEC 60780 equipment qualification: Demonstration by means of analyses, type tests, or operating experience that the equipment is able to function within its required accuracy and performance requirements in all required operational and environmental conditions IEEE 323 equipment qualification: Generation and maintenance of evidence to assure that equipment will operate on demand to meet system performance requirements during normal and abnormal service conditions and postulated design basis events 3
Shows Notable Consistency (cont) Qualification Methods Type testing, operating experience, analysis, or a combination of all three, are allowed in both versions Type testing is explicitly stated as the preferred method in IEC 60780 On-Going Qualification Procedures and conditions for on-going qualification in IEEE 323 envelop those stipulated in IEC 60780 Qualification by Operating Experience IEEE 323 envelopes IEC 60780 Qualification by Analysis IEEE 323 explicitly allows qualification of other equipment by similarity if certain criteria are met 4
Shows Notable Consistency (cont) Aging Both versions have provisions for situations where aging may not be required IEEE 323 requires preconditioning based on the determination of significant aging mechanisms IEC 60780 refers to the existence of significant ageing factors in the application of accelerated aging IEC 60780 embodies detailed guidance on accelerated aging Temperature, radiation, wear (prolonged operation in IEC 60780), and vibration are indicated age conditioning factors in both versions while IEC 60780 explicitly includes corrosion 5
Shows Notable Consistency (cont) Test Sequence Basic test sequence elements are similar Electromagnetic (EMI/RFI) susceptibility tests are required by IEC 60780 Aging prior to seismic testing is not required under IEC 60780 if equipment not to be subject to accident conditions IEC 60780 defines three test groupings that may be treated independently and may be conducted on different samples Functional (normal conditions and extremes) Seismic (preconditioning not required if equipment not intended to be subject to accident conditions) Accident and post-accident (including aging as initial step) IEEE 323 establishes a test sequence for qualification: testing under normal conditions and anticipated extremes, thermal aging, irradiation to aging plus accident dose, vibration and seismic testing, DBA (e.g., MSLB/LOCA) testing, and post-dba testing, as applicable IEC 60780 gives more detailed guidance on preferential stresses and standardized tests 6
Shows Notable Consistency (cont) Margins Suggested factors to be applied to service conditions for type testing are essentially the same in both standards IEC 60780 identifies the suggested margins as applying to operational conditions for type testing but identifies specific margins for thermodynamic accident conditions IEEE 323 provides suggested margins for DBE service conditions and notes that they do not apply to age conditioning Documentation IEC 60780 makes no distinction between harsh and mild environments IEEE 323 provides separate guidance on documentation files for equipment in mild environments Design/purchase specification and certificate of conformance that the equipment meets the requirements of the specification are acceptable 7
Interaction Between IEC Working Group 9A and IEEE Subcommittee 2.1 Is Encouraged Coordination between IEC-IEEE based on Type 2 liaison interaction IEC Project Team is being formed Next IEC Meeting in London (March 2008) Additional working group meeting possible to enable joint technical discussion Interest in participation should be communicated to Project Lead (Wood) WG9A membership established through National Committee Technical experts can participate as advisors 8