EPRI, in collaboration with USDOE, have developed a set of requirements to establish the technical basis for the design of advanced light water reactors (ALWRs) (IAEA — TECDOC-968, 1997). A first objective is to establish a basis for licensing future LWRs, including the resolution of outstanding severe accident issues, and to gain agreement with the USNRC. Secondly, there is an objective to provide a standardised plant design with vendor certification. Thirdly, there is an intention to provide a set of technical requirements, to minimise the risks to investors in completing and operating the first ALWR.

The EPRI Utility Requirement Document (URD) covers top-level programme policy statements and detailed requirements for specific ALWR designs. It includes large evolutionary systems with improved active safety systems and also passive system designs including natural circulation, gravity-driven refill and stored energy as essential safety functions. Both passive PWR and BWR systems are included.

The document was first published in 1990 and has been used in the development of several new LWR designs. It has been developed by the US utilities to reflect the procedures’ rules, regulations, codes and standards of the US. However, there have also been contributions from European utilities, which have developed their own set of standards, as discussed below.