Cost analysis for potential BWR Mark 1 containment improvements

The Nuclear Regulatory Commission (NRC) has identified several potential improvements to BWRs with Mark 1 containments. The Mark 1 containments have been chosen for this initial effort because they appear to have a relatively high conditional probability of failure for severe accidents. This study is a cost analysis of three potential areas of Mark 1 containment improvement. Considered were: Automatic Depressurization System (ADS) enhancements; back-up water supply enhancements; and wetwell venting enhancements. These cost analyses are comprehensive. In addition to the costs of physical modifications, they also include aspects such as engineering and quality assurance, radiation exposure, health physics support, and anti-contamination clothing. Also considered are licensee costs associated with technical specification changes, writing or rewriting operating procedures, and staff training. The analyses show that the industry costs per reactor for installation of all improvements range from about $1.6 million for the low cost options to $3.15 million for the high cost options. In addition, these physical modifications are estimated to result in occupational radiation exposures ranging from about 20 person-rem to 150 person-rem per reactor. 7 refs., 5 figs., 1 tab.