Key developments of the EP1000 design

In 1994, a group of European utilities initiated, together with Westinghouse and its industrial partner GENESI (an Italian consortium including ANSALDO and FIAT), a program designated EPP (European Passive Plant) to evaluate Westinghouse passive nuclear plant technology for application in Europe. The Phase I of the European Passive Plant program involved the evaluation of the Westinghouse 600 MWe AP600 and 1000 MWe Simplified Pressurized Water Reactor (SPWR) designs against the European Utility Requirements (EUR), and when necessary, the investigation of possible modifications to achieve compliance with the EUR. In Phase 1 of the program, which has been completed in 1996, the following major tasks were accomplished: The impacts of the European Utility Requirements (EUR) on the Westinghouse nuclear island design were evaluated. A 1000 MWe passive plant reference design (EP1000) was developed which conforms to the EUR and is expected to be licensable in Europe. With respect to the NSSS and containment, the EP1000 reference design closely follows those of the Westinghouse SPWR design, while the AP600 design has been taken as the basis for the design of the auxiliary systems. Extensive design and testing efforts have been made for the AP600 and SPWR during the respective multi-year programs. While the results of these programs have been and will continue to be utilised, at the maximum extent, to minimise the work to be performed on the EP1000 design, the compliance with EUR is a key design requirement for the EP1000 The ultimate objective of Phase 2 of the program is to develop design details and perform supporting analyses to produce a Safety Case Report (SCR) for submittal to European Safety Authorities. The first part of Phase 2, hereafter referred as Phase 2A, started at the beginning of 1997 and will be completed at the end of 1998. Scope of this phase of the program is to develop the design modifications of important systems and structures so to comply with the EUR. This paper provides a brief description of the most significant developments of the EP1000 plant design during Phase 2A of the EPP program. (author)