Phenomena Identification and Ranking Table Evaluation of Chemical Effects Associated with Generic Safety Issue 191

The U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors (PWRs)," on September 13, 2004, as the primary vehicle for addressing and resolving concerns associated with Generic Safety Issue 191, "Assessment of Debris Accumulation on PWR Sump Performance." Additionally, the NRC staff developed a safety evaluation of industry-developed guidance to provide an accepted method for evaluating PWR sump performance as requested in Generic Letter 2004-02. However, the safety evaluation and the industry guidance document provide little guidance for assessing chemical effects. The licensees are to address chemical effects on a plant-specific basis.