High intensity forging for nuclear applications Manufacturing and properties of nozzle shell with integral flange for EPR reactor pressure vessel T. Berger 1 , E. Murai* 2 , I. Kurihara 3 , T. Nakamura 4 , T. Sasaki 4 , T. Yoshida 4 and Y. Koyama 4 The EPR (European Pressurised Water Reactor) developed by AREVA is a new nuclear reactor designed to achieve greater output (1600 MW) and longer plant life (60 years) than conventional nuclear reactors. The first one is currently under construction in Finland at Olkiluoto. For this new design, an integrated forging was applied for the nozzle shell, including an integral flange (Fig. 1). A 500 t ingot is necessary to manufacture this part, which was the first large part manufactured on a new 14 kt press installed at JSW in 2003. The part was completed 11 months after pouring. The technologies of each manufacturing step and the properties of the part are described. Materials for pressurised water reactor pressure vessel (PWRPV) The first material for a PWRPV manufactured by Japan Steel Works, Ltd (JSW) was a forged flange for Tsuruga #1 reactor. Subsequently, the following parts have been developed to achieve the elimination of welding and to manufacture the large components required for increasing output in nuclear power plants These are (Fig. 2): N integrated closure head N core region shell N vessel flange (nozzle shell with integral flange). The integrated closure head is a combination of dome and flange. The part is manufactured with a rotating die forging process developed by JSW, 1 and can be completed with a earlier delivery than that of the welded type or by the blank forming process. Many integrated closure heads have been manufactured with this method, most being replacements in the USA and Japan. The core region shell has been also integrated into one piece to eliminate weldments. In addition, impurity elements, especially Cu content, have to be controlled as low as possible to avoid irradiation embrittlement in service. The integrated core region shell has been applied in a number of domestic plants such as Tsuruga#2, 2 Japan, Qinshan#1 in China and Sizewell B in the UK. Welded type vessel flanges (flange, shell and nozzles) have been applied before the integrated type was developed. The first integral type was for Biblis B, Germany which was manufactured from a 400 t ingot. A more recent experience was for a domestic plant, Tomari#3. A combined Vessel Flange with Nozzle was manufactured for Belgium, DOEL#4, where a 500 t ingot was required. 3 These manufacturing experiences were the basis for production of a nozzle shell with integral flange for the EPR. Manufacturing of nozzle shell with integral flange The manufacturing sequence, shown in Fig. 3, took 11 months to complete. 1 Purchasing Quality Dept., Saint Marcel Plant, AREVA NP 2 Deputy General Plant Manager, Muroran Plant, Japan Steel Works, Ltd 3 Steel Component Dept., Muroran Plant, The Japan Steel Works, Ltd 4 Nuclear Engineering Gr. Forged Product Dept., The Japan Steel Works, Ltd *Corresponding author, etuo_murai@jsw.co.jp 1 Schematic layout of EPR pressure vessel 2 Details of PWR pressure vessels: materials and experience ß 2007 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute DOI 10.1179/174328107X174717 Ironmaking and Steelmaking 2007 VOL 34 NO 3 205