12.183. Following the accident, major reviews were carried out which proposed many reforms covering both industry and the Nuclear Regulatory Commission (NRC), most of which have since been implemented. In the industrial area, improvements fall into four categories:

1. Plant performance review and personnel training

2. Operational regulations

3. Plant equipment improvements

4. Research

12.184. In the first category, the Institute of Nuclear Power Operations (INPO) was established to perform in-depth analysis of operating expe­rience and serve as a clearinghouse for information. Training and ac­creditation programs were established. Second-category changes include provision for additional technical staff on each shift and extensive im­provements in operational procedures.

12.185. The third category is concerned with hardware. Major changes were made in control rooms and system instrumentation. New venting in the primary system was provided, for example. Hundreds of changes were required for each plant at a cost in the range of hundreds of millions of dollars per plant. A measure of improvement has been a reduction in the number of significant events, defined by NRC as one that has a potential safety implication. Research in such areas as source terms and degraded core analysis was expanded.

12.186. All of the measures taken certainly improved the safety of op­erating reactors in the United States and certain other countries that adopted the same measures. The accident demonstrated the value of the contain­ment since the public was not affected by an almost worst-case accident. In addition, the “cleansing” of the fission product mix through the con­version of volatile iodine proved the need for extensive source term studies. Yet the fact that the accident was even possible seriously eroded the public image of nuclear power as an almost foolproof technology.