| 1. |
- Ballesteros, Antonio, et al.
(författare)
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Reactor Pressure vessel surveillance
- 2014
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Ingår i: Nuclear Engineering International. - : GLobal trade media. - 0029-5507. ; 59:12, s. 19-20
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Tidskriftsartikel (refereegranskat)abstract
- This publication summarizes techniques suitable for surveillance program for the objective of long term operation (LTO) on European NPPs and provides recommendations on reactor pressure vessel (RPV) irradiation surveillance based on the work preformed in the work package 7 "Surveillance guidelines" of the LONGLIFE international project. The LONGLIFE project "treatment of long term irradiation embrittlement effects in RPV safety assessment" was 50% funded by the Euratom 7th framework programme of the European commision. The project coordinated by the Helmholtz-centrum Dresden Rossendorf successfully finalized in 2014.
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| 2. |
- Hein, Hieronymus, et al.
(författare)
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CARINA : A program for experimental investigation of the irradiation behaviour of German Reactor Pressure Vessel materials
- 2013
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Ingår i: ATW. Internationale Zeitschrift für Kernenergie. - 1431-5254. ; 58:5
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Tidskriftsartikel (refereegranskat)abstract
- The proof of a sufficient safety margin against brittle fracture of the reactor pressure vessel (RPV) is an important part of the operational safety of nuclear power plants. The RPV safety assessment procedure applicable in Germany is described in KTA 3201.2 of the Nuclear Safety Standard Commission (KTA). This deterministic assessment concept is based on the comparison of load curves with the material resistance curve in terms of fracture toughness. The fracture toughness curve can be determined either indirectly according to the RT-(NDT) concept based on Charpy tests or directly according to the more appropriate RTT0 approach based on Master Curve analysis of fracture toughness tests, respectively. In the recently completed research project CARINA the data base for pre-irradiated original RPV steels of German PWR construction lines was extended by comprehensive fracture toughness testing. The data obtained up to neutron fluences of 7.67 x 10(19) n/cm(2) (E > 1 MeV) are analysed and discussed particularly in terms of Master Curve applications. The experimental results show that optimized RPV manufacturing specifications and reactor designs are advantageous for a long-term plant operation in comparison to less optimized materials with lower toughness and to reactor designs with substantial higher neutron irradiation. With the obtained data, experiences and insights an essential contribution was also made to the integration of the Master Curve concept in German safety standards.
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| 3. |
- May, Johannes, et al.
(författare)
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Extended mechanical testing of RPV surveillance materials using reconstitution technique for small sized specimen to assist Long Term Operation Extended mechanical testing of RPV surveillance materials using reconstitution technique for small sized specimen to assist Long Term Operation
- 2014
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Ingår i: Journal of ASTM International. - : ASTM International. - 1546-962X .- 1546-962X. ; STP:1576
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Tidskriftsartikel (refereegranskat)abstract
- For the Ringhals 3 and 4 PWR RPV, results from the irradiation surveillance program are available also for neutron fluences which cover long-term operation (LTO). These standard surveillance results are based on the RTNDT concept. The belt-line welds of both RPVs have an elevated nickel-content of 1.6 wt.-% and, as a consequence, irradiation response is higher than predicted by model equations. Therefore, the mechanical testing program has been expanded, exceeding the requirements of the standard testing program and covering both base and weld materials. To improve the understanding of the material behavior, extended Master Curve testing was performed on PCCV and subsize SE(B) specimens from irradiation surveillance capsules with the help of specimen reconstitution technique. Special care has been taken on the limited amount of weld material within the available broken Charpy halves before specimen reconstitution.Results have been compared to existing data on similar base and weld materials from the German research programs CARISMA and CARINA. Late-blooming effects or sudden saturation effects are not observed for base or weld materials under LTO conditions. The data for the four different weld materials of similar chemical composition indicate that not only the chemical composition, but also other influencing factors like e.g. the welding heat treatment may be important for the reference temperature of the unirradiated state as well as for the irradiation behavior. To investigate this effect more in detail, a future investigation program will be discussed including manufacturing of a surrogate weld material with the same chemical composition as in Ringhals 3 and 4 RPV. The influence of heat treatment condition can be investigated by applying different heat treatments and subsequently performing test reactor irradiation and mechanical testing. Specimen reconstitution will be required due to limited space inside the test reactor irradiation capsules.
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| 4. |
- Roudén, Jenny, et al.
(författare)
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Towards Safe Long-Term Operation of Reactor Pressure Vessels
- 2015
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Ingår i: ATW. Internationale Zeitschrift für Kernenergie. - : Nucmag.com. - 1431-5254. ; 60:5, s. 287-293
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Tidskriftsartikel (refereegranskat)abstract
- This publication summarizes the long term operation (LTO) conditions on European NPPs and provides recommendations on reactor pressure vessel (RPV) irradiation surveillance based on the work preformed in the work package 7 "Surveillance guidelines" of the LONGLIFE international project. The LONGLIFE project "treatment of long term irradiation embrittlement effects in RPV safety assessment" was 50% funded by the Euratom 7th framework programme of the European commision. The project coordinated by the Helmholtz-centrum Dresden Rossendorf successfully finalized in 2014.
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