In-service Inspection of Nuclear Facility Pressure ... Equipment with Non-destructive ... • These...

SÄTEILYTURVAKESKUS • STRÅLSÄKERHETSCENTRALEN

RADIATION AND NUCLEAR SAFETY AUTHORITY

In-service Inspection of Nuclear Facility Pressure Equipment with Non-destructive

Testing Methods Safety and Regulation of Nuclear Power Plants

Elina Salenius

Inspector

Technical Meeting on the Optimization of

Non-Destructive Examination and In-Service Inspection

to Improve Nuclear Power Plant Performance

VTT Espoo 4.-7.4.2017



Contents of Presentation

1. In-service Inspection-related Requirements in Finnish Legislation

2. Scope of application of YVL Guide E.5

3. In-service inspection requirements

4. Qualification of Inspection Systems

5. Overview of Pre-Service Inspections ongoing at Olkiluoto 3

6. Justification for the Requirements of Regulatory Guide YVL E.5

7. Comparison with International Regulations /Practices



In-service Inspection-related Requirements in Finnish Legislation

3

Nuclear Energy Act (990/1987) (nontechnical level, authorises STUK to

specify detailed safety requirements )

Nuclear Energy Decree (161/1988) (technical prerequisites)

Former Government Decree on the Safety of Nuclear Power Plants

(717/2013), present Radiation and Nuclear Authority Regulation on the

Safety of a Nuclear Power Plant (STUK Y/1/2016)

YVL Guides are less obligatory than the acts and decrees. Therefore the licensee may propose an alternative approach if the licensee can demonstrate that same safety level is achieved.




• Nuclear Energy Act (990/1987): The safety of nuclear energy use shall be maintained at as high a level as practically possible. For the further development of safety, measures shall be implemented that can be considered justified considering operating experience, safety research and advances in science and technology.

• According to Section 7 e of the Nuclear Energy Act (990/1987), compliance with requirements concerning the safety of a nuclear facility shall be proven reliably.

• According to Section 9 of the Nuclear Energy Act (990/1987), it shall be the licensee’s obligation to assure safe use of nuclear energy. This obligation cannot be delegated or transferred to another party.




• Nuclear Energy Decree (161/1988): the licensee shall apply for STUK’s approval of the qualification body.

• Section 35 of the Nuclear Energy Decree (161/1988) stipulates that an applicant shall submit a plan for principles of in-service inspections to STUK together with the application for a construction licence.

• Section 36 the Nuclear Energy Decree (161/1988) stipulates that the applicant shall submit a summary programme for periodic inspections to the Radiation and Nuclear Safety Authority when applying for an operating license.

5




• Nuclear Energy Decree(161/1988) Under Section 113 b: Non-destructive testing during in-service inspections of nuclear facility structures and components significant for nuclear safety can only be conducted using testing systems qualified by a STUK-approved qualification body.

• Requirements under Section 117 b of the Nuclear Energy Decree (161/1988) for inspection bodies, shall also apply to qualification bodies.

• Section 23 § of the Radiation and Nuclear Authority Regulation on

the Safety of a Nuclear Power Plant (STUK Y/1/2016) integrity of

structures and components shall be monitored by inspection.



YVL Guide E.5 (3.8) Scope of application

• The requirements for the planning, qualification, implementation, reporting and supervision of the in-service inspections performed on the pressure equipment of nuclear power plants using non-destructive testing methods.

• Inspections shall be performed on pressure equipment belonging to safety classes 1 and 2 and other pressure equipment that is considered significant in terms of nuclear safety.

• The piping in-service inspection programme shall be prepared in a risk-informed manner, analysing all of the nuclear facility’s systems in safety classes 1, 2, 3, and EYT (non-nuclear) as a single complex independently of the safety classifications and nominal dimensions of the piping.

• The inspection systems shall be qualified.



In-service inspection requirements

• Plan for principles of in-service inspections

• Pre-service inspection plan

– The licensee shall submit the pre-service inspection plan for a new nuclear plant unit to STUK for approval no later than six months before the planned date of inspection.

• Summary programme for in-service inspections (linked to operating licence)

• In-service inspection programme for an inspection interval

• Inspection plans for operation periods

• Risk-informed selection process

– In Finland risk informed applications are part of all regulatory process of Nuclear Power Plants life cycle.

– Risk-informed piping pre-service inspections (OL 3 unit)

– The risk-informed piping in-service inspections must include all systems of a plant

8



Qualification of NDT inspection systems 1/6

• These are probably the most time-consuming and technically demanding requirements presented for the plant supplier in Guide YVL E.5

• Practice created by the EU countries

• Inspection system: Inspection procedure, equipment and personnel

• What degradation mechanisms could occur in a structure?

• Inspection objectives: what kind of defects must be correctly detected, characterised and sized?

• Qualification must demonstrate achievement of the inspection objectives

– Qualification body makes the qualifications

– Qualification main parts: technical justification and practical trials




• Qualification is the only way of assessing inspection reliability in advance

• Qualification body holds the most important role in this assessment

• Qualifications (typically 30-50 different qualifications at a PWR plant) to be accomplished three months before preservice inspections

• According to European experience, one qualification takes at least a year (NRWG, EUR 20819)

• The process of qualification cannot be started without an accredited and STUK-approved qualification body

• The input information documents are the first phases of qualification

10




• Qualification basic level: ENIQ documents

– European Network for Inspection and Qualification (ENIQ)

– The European Methodology for Qualification (EUR 17299)

– ENIQ Recommended Practices

• Qualification documents

– Qualification body compiles the qualification documents and the licensee submits them to STUK (for information or approval)

– The qualification input information (licence-applicant prepares and submits to STUK for approval after their approval by the qualification body)

– The inspection system subject to qualification(qualification body qualifies, approval by STUK can indirectly follow based on the document dossier, and particularly based on the qualification assessment report and the qualification certificates)




• Qualification procedure (qualification body prepares, to STUK for information)

• Technical justification (testing organization prepares, qualification body assesses, to STUK for information)

• Practical trials (qualification body assesses, co-operates with testing organization, to STUK for information)

• Qualification assessment report (qualification body prepares, to STUK for approval)

• Qualification certificates (qualification body prepares, to STUK for information)



Pre-Service Inspections ongoing at Olkiluoto 3

• Qualifications of all the NDT inspection systems of the new nuclear power plant under construction

Already finalized inspections:

• Reactor Pressure Vessel: Vessel welds, nozzles, studs and threads

• Reactor Pressure vessel Closure Head flange weld

• Steam Generator: Tubing

• Auxiliary and secondary piping

• Pressurizer surge line

Ongoing:

• Main Coolant Lines

• Steam Generator welds and nozzles

• Pressurizer welds and nozzles



PSI RPV inspection at Olkiluoto 3

[AREVA NDE-Solutions ANP:U-360-V2-13-ENG PWR Vessel Examination TWS Manipulator for Nozzle and Vessel UT Examination]



Justification for the Requirements of Regulatory Guide YVL E.5 1/2

• All the requirements have been justified separately based on the following references and practices:

– Nuclear energy legislation and other legislation

– IAEA Safety Standards Series No. NS-G-2.6, Safety Guide, Maintenance, Surveillance and In-Service Inspection in Nuclear Power Plants, Vienna, 2002

– WENRA Reactor Safety Reference Levels, January 2008, Issue K: Maintenance, In-service inspection and Functional Testing

– The most important reference for inspection programs: ASME Boiler and Pressure Vessel Code, Section XI, Rules for In-service Inspection of Nuclear Power Plant Components, Division 1 (ASME Code, Section XI)

– The most important reference for qualification: Publications of ENIQ, European Network for Inspection and Qualification

– Rules and requirements of nuclear regulatory bodies of other countries, NRWG



Justification for the Requirements of Regulatory Guide YVL E.5 2/2

– Research, development and experiences in Finland and abroad

• Nuclear power plants under design, construction and in operation

– Established and proven good Finnish practice; the requirements have already been presented in the 1982 revision of Guide

– Official positions given by STUK, such as:

• Radiation and nuclear safety in Finland is of a high quality and leads the way in the field internationally

– Other justifications



Comparison with International Regulations 1/2

• Main principles of following international principles are fulfilled:

– ASME Boiler and Pressure Vessel Code, Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Division 1 (ASME Code, Section XI)

– IAEA Safety Standards Series No. NS-G-2.6, Safety Guide, Maintenance, Surveillance and In-Service Inspection in Nuclear Power Plants, Vienna, 2002

– U.S. NRC Regulatory Guide 1.14 Reactor Coolant Pump Flywheel Integrity Revision 1, August 1975

– Publications of ENIQ, European Network for Inspection and Qualification

– Report on the Regulatory Experience of Risk-Informed Inservice Inspection of Nuclear Power Plant Components and Common Views, Prepared by The Nuclear Regulators’ Working Group, Task Force on Risk-Informed Inservice Inspection, Final Report – August 2004, EUR 21320 EN (comprehensive overview, consensus document)



Comparison with International Regulations 2/2

– ASME Code, Section XI, Nonmandatory Appendix R, Risk-informed Inspection Requirements for Piping.

– Supplementary instructions are presented in the European Network for Inspection and Qualification’s (ENIQ) framework document concerning risk-informed in-service inspections (Thoroughgoing overview to RI-ISI framework)

– Common position of European regulators on qualification of NDT systems for pre- and in-service inspection of light water reactor components, EUR 16802 EN (connects qualification and nuclear safety)

– WENRA Reactor Safety Reference Levels, January 2008, Issue K: Maintenance, In-service inspection and Functional Testing



Thank you for your attention!

21

In-service Inspection of Nuclear Facility Pressure ... Equipment with Non-destructive ... • These...

Documents

Transcript of In-service Inspection of Nuclear Facility Pressure ... Equipment with Non-destructive ... • These...