Maintaining Nuclear Reactor Components Performance and Integrity for Plant Safety

Transcription

1 Boosting your Excellence through Knowledge and Training Maintaining Nuclear Reactor Components Performance and Integrity for Plant Safety Academy Academy Academy Seminar objective Academy Generally, well-run nuclear power plants (NPP) operate at high efficiency of greater than 85 percent. Such operation is possible because of robust design of systems, structures, and components (SSC) of a reactor, operation, periodic inspection and maintenance, which strictly follows consensus codes and standards. Safety and reliability of nuclear power plants are essential requirements for long term operation. During operation of a nuclear power plants materials degradation has to be taken into account so the quality condition of a reactor component or parts of the plant during lifetime may be reduced by ageing. This degradation phenomenon, contributed by the interaction of the component materials with the reactor environment, is due to the operation of several physical and chemical interactions and mechanisms, such as wear, erosion, corrosion, flow accelerated corrosion, stress corrosion cracking, general corrosion, mechanical and thermal fatigue, and degradation due to embrittlement by irradiation. Continuous evidence of the necessary precautions in sense to ensure performance and integrity are the most important duties of nuclear power plant operators. Those efforts should be applied to major systems, structures, and components SCCs important to safety. Page 1 (8)

2 The operating organisation shall be aware of possible consequences in case of failure and determine needful activities. In the past some severe incidents (Davis Besse, Mihama, V.C. Summer) happened which are linked with grave materials degradations so loss of function or integrity occurred. From these incidents the nuclear industry has drawn consequences and improved their safety culture. An attendee of the seminar will gain: The planned ANT seminar follows previous seminars offered by ANT International on aspects related to degradation experienced by nuclear reactor components. It will give an overview of the world wide operational experience with major SCCs in nuclear power plants (PWR, BWR). Herby various examples of reactor components are presented suffering degradation due to specific ageing mechanisms. Measures to prevent failure and precautions to maintain component performance and integrity to ensure long term operation are presented. (i) (ii) (iii) Enhance the awareness and provide practical information relevant to implement component monitoring and addressing ageing in nuclear plantoperation, including the current status of nondestructive examination methods used; Provide practical information on previously experienced ageing of components including, but not limited to, reactor pressure vessel (RPV), RPV internals, core shroud, piping, nozzles, steam generator tubes, and dissimilar metal welds that accompany such components and others; and, Present refurbishing concepts in case of degradation incidents. Component degradation could potentially lead to the breach of the coolant pressure boundary in safety-related and important-to-safety reactor components resulting in unacceptable coolant leakage, as a consequence uncontrolled damage inside of the plant or the risk of unplanned reactor shut down may happen. Safe reactor operation takes into account such potential ageing degradation of various components, and monitors the condition of components both online and offline, for example by operations monitoring of transients or non destructive testing (NDE) during refueling outage. When any such degradation is detected ageing management procedures are invoked to Page 2 (8)

3 assure continued safe reactor operation until the next outage. Such procedures involve the knowledge of degradation mechanisms, applicable national and international inspection codes and standards. An important issue for RPV safety deals with material degradation due to irradiation at high fluences in the core beltline region of the RPV. Hereby a plant specific surveillance program with irradiated samples in hot cells has to be performed to characterize material properties after extrapolated operating time. In case of a supposed loss of coolant accident the irradiated RVP beltline region in PWR is subjected to a pressurized thermal shock (PTS). For this load case it must be proved that the material properties in the irradiated condition are sufficient to exclude brittle fracture of the RPV. Seminar information and content Who should attend Engineers and technical managers at utilities, reactor vendors and regulators who would like to get a deeper knowledge of Maintaining Components Performance and Integrity for Plant Safety. Content The content of the Seminar is covered in the Appendix. Schedule The Seminar starts on Wednesday morning and finishes on Friday afternoon, March 1 3, 2017 in Palma de Mallorca, Spain. Considering breaks and lunches, the total presentation time of the Seminar is about 25 hours. The week selected for the Seminar is the week before the ZIRAT Seminar. The same hotel is used for the Seminar as for the ZIRAT Seminar. Lecturer information The Seminar is held by Mr. Francois Cattant and Dr. Ulf Ilg. François Cattant graduated in chemical engineering and joined EDF in In 1976, he moved to the hot laboratory. In 1980 he moved to the northern part of France, as manager of the local chemistry and non-destructive examination section. In 1983, he moved back to the hot laboratory, as metallurgical and mechanical testing section manager. In 1987, he was promoted to hot laboratory deputy manager and in 1991 promoted again as hot laboratory technical manager. Between 1995 and 1998 he was loan-in to the Nuclear Maintenance Application Center at EPRI Charlotte (NC, USA). In 1998 he moved back to France, at the R&D Materials and Mechanics of Components department where he stayed until his retirement in In 2010, he was sponsored by the MAI (Materials Ageing Institute, EdF) to write a Handbook of Destructive Assays, a 1100 pages document putting together extended summaries of hundreds of destructive examinations performed on LWRs NSSSs, in France, US, Japan and Sweden. Page 3 (8)

4 Dr. Ulf Ilg received his first degree as Diplom-Ingenieur in Mechanical Engineering from the Technical University Karlsruhe (today KIT), Germany. His Ph.D was obtained at the same university after a scientific research period of 5 years in the field of microstructure and residual stress alteration due to rolling contact fatigue. Since 1981 he was in charge of the German utility EnBW. At that time his major activities had been project engineering for fossil, hydroelectric and new nuclear power plants. Later he was responsible for reactor engineering materials, structural integrity and ageing management at the nuclear power plant Philippsburg (one BWR and one PWR), EnBW Kernkraft (Germany). Deliverables Before the Seminar, the Seminar presentation material is provided via our web-page. After the Seminar, a certificate of seminar attendance will be issued by to the participants. Price Please contact Ms. Angela Olpretean, either via angela.olpretean@antinternational.com or by phone , to get an offer. A significant discount is given if several staff members from the same company/organization participate in the Seminar. The Seminar will only be provided if at least 10 people sign up for this Seminar. The maximum number of seminar participants will be 25. Participants will be determined on a first come, first served basis. Purchase order Purchase orders should be made out to and addressed to Advanced Nuclear Technology International, Analysvägen 5, SE Mölnlycke, Sweden. Billing for the total amount will be done after the purchase order has been received and payment will be due 30 days after receipt of the bill. All prices and costs exclude VAT and any non-swedish taxes and custom expenses. Terms and conditions shall exercise its best efforts to meet the objectives in this assignment and will apply professional personnel with the required skills, experience and competence to the work. If the assignment, within 6 months of its completion, is judged by the customer to be seriously deficient, shall modify the work done within this assignment in such a way that it will become satisfactory to the customer. This modification shall be done without incurring any additional costs to the customer. The total amount of such additional costs due to the modification shall be limited to be less or equal to the total amount originally paid to for this assignment. It is understood that and the lecturers are not responsible for any damage, incurred to the customer, their employees, or their plants or to a third party due to the Page 4 (8)

5 use of the information or the recommendations given within this assignment. The compiled information and the conclusions, as a result of this work, may be used by the purchasing party for its own internal and external use for any purpose. retains the rights to the compiled information and the conclusions for other uses. Nuclear Liability and its sub-suppliers, including also suppliers of information and services, of every tier and kind, and everyone engaged by any of them, shall have no liability whatsoever (irrespective of negligence or gross negligence) for any damage or loss whatsoever (including also consequential and indirect loss) resulting from a nuclear incident (as such term is defined in the Paris Convention on third party liability in the field of nuclear energy, as amended from time to time). This shall apply for damage or loss suffered by third parties or the owner and for damage and loss to the nuclear installation, on site property and any other property of any kind, and until the nuclear installation has been definitely decommissioned and irrespective of any termination or cancellation of the proposed work. Insurances of the owner and of others in respect of a nuclear incident shall exclude any right of recourse against the supplier and his sub-suppliers of every tier and kind. Page 5 (8)

6 Additional Information Please review the information and contact Ms. Angela Olpretean, either via or by phone , if you have any questions or comments. Best regards, Peter Rudling, President Office Address: Advanced Nuclear Technology International, Analysvägen 5, SE Mölnlycke, Sweden. Phone: +46 (0) Fax: +46 (0) Page 6 (8)

7 APPENDIX Maintaining Nuclear Reactor Components Performance and Integrity for Plant Safety Seminar outline: 1. Brief description of the various types of LWRs and of their main components relevant for safety 2. Materials and materials properties 3. Review of Non Destructive Testing technologies used in LWRs 4. WENRA Safety Level, Issue I: Ageing Management 5. Field experience with PWR components: a. Reactor Pressure Vessel (RPV) and RPV internals b. Pressurizer c. Steam Generator d. Reactor Cooling System (RCS), piping and main coolant pumps e. Systems attached to the RCS: CVCS, SIS, RHR, CCS, f. Balance of plant 6. Field experience with BWR components a. Core shroud b. Austenitic stainless steel piping systems c. Ferritic steel piping systems d. Dissimilar welds incl. CRDM-nozzles 7. Refurbishing concepts in case of degradation incidents (BWR) a. Optimised materials b. Optimised manufacturing processes c. Optimised material selection and manufacturing of dissimilar welds 8. Degradation in LWR components and Mitigation Techniques a. Boric acid corrosion b. Degradation by foreign objects c. Wear issues d. Corrosion mitigation techniques 9. Operational surveillance and measures to maintain component performance or reduction of dose rate a. Temperature transients with regard to fatigue b. Control of water chemistry in BWR (e.g. Co-60 activity after replacement Page 7 (8)

8 control rods) with regard to reduce the dose rate of the plant c. Irradiation samples in the frame of surveillance program (Post characterisation of irradiated RPV material, PWR as well as BWR) 10. Brittle fracture analysis of RPV in case of PTS (pressurized thermal shock) in PWR 11. Integrity concept for piping systems with corresponding leak and break postulates in LWR to ensure long term operation Page 8 (8)