[en] The US Nuclear Regulatory Commission (NRC) has prepared Supplement 1 to the final Integrated Plant Safety Assessment Report (IPSAR) (NUREG-0823), under the scope of the Systematic Evaluation Program (SEP), for the Commonwealth Edison Company (CECo) Dresden Nuclear Power Station, Unit 2 located in Grundy County, Illinois. The NRC initiated the SEP to provide the framework for reviewing the design of older operating nuclear reactor plants to reconfirm and document their safety. This report documents the review completed by means of the SEP for those issues that required refined engineering evaluations or the continuation of ongoing evaluations subsequent to issuing the final IPSAR for Dresden Unit 2. The review was provided for (1) an assessment of the significance of differences between current technical positions on selected issues and those that existed when Dresden Unit 2 was licensed, (2) a basis for deciding on how these differences should be resolved in an integrated plant review, and (3) a documented evaluation of plant safety. The final IPSAR and this supplement forms part of the bases for considering the conversion of the existing provisional operating license to a full-term operating license. 83 refs., 9 tabs