This paper addresses a complex debate of national importance related to the safety of existing light water reactors and preventing, mitigating, or improving emergency preparedness for response to severe reactor accident releases of radioactivity for operating reactors. The costs and benefits of several key alternatives are assessed for the NUREG-1150 reference plants, as well as, a representative medium population density site. Annual levelized cost calculations using a 105 annual release rate were made using ICRP annuity factors for potential safety improvements resulting in cost-beneficial justifications for engineering safety improvements such as supplemental filtering and scrubbing to the present containments, and for instrumentation and monitoring to minimize a bypass scenario. Probabilistic risk financing formulas for expected continuous discounting are presented. Improvements to emergency preparedness measures such as stockpiling potassium iodide for the population would not have the additional protection benefits of reducing substantially non-inhalation pathway contributions to offsite health effects, as well as, protecting land from contamination.