IRIS-economics review

IRIS is a medium sized advanced light water cooled modular reactor being developed by an international Group led by Westinghouse/BNFL. This reactor design is aimed at a broad spectrum of Utilities looking to install nuclear capacity to match market demands, or at emerging Nations with specific financial constraints looking to strategically optimise their debit levels. The IRIS building block is a multiple module sized at 335 MWe, with a construction period of 3 years and a 60-year plant life. Modules can be installed individually or in parks. In the latter case, deployment can be in single modules or in pairs (twin-unit); both will be built in staggered fashion at time intervals as dictated by economic and market considerations. One of the unique features of IRIS is its ability to offer reduction in costs through increased experience 'Learning' at a single site: In construction, the principal benefit is derived for subsequent modules, and is dependent on maintaining the 'core' team throughout. This is particularly important if there is any significant period between the completion of say module 1 and the start of module 2. This time frame will be driven by the overall market size, projected growth in demand and the level of financial risk the utility is prepared to accept. Learning benefits in construction are derived from skills and experience retention impacting on reducing the number of inputs and construction time. Learning in operation may benefit from a certain delay between modules as this allows operators to build up their 'cumulative experience'. Reactor operations on day 1 would be significantly different from those of say 3 years later. These benefits would be passed on to modules 2 and 3, which would realise them from day 1. Learning in operation is dependent on the ability to retain within the organisation knowledge and records of key events. The benefits from Learning in operation may also be applicable to different sites, in different countries. It would certainly be possible to share operational experience within a country or organisation across several dispersed sites in large countries like Brazil. Because of the IRIS Group structure it is also possible to share experience among different organisations and countries operating IRIS modules. (authors)