Changes that Count

Continuous improvement is considered vital for maintaining the high safety standard. However, it may have down side. A nuclear criticality accident happened at a nuclear fuel processing factory in Japan illustrates a typical downside. Procedures for manufacturing enriched uranyl nitrate solution had been changed over the years before the accident occurred. The changes were potentially unsafe and must not have been authorized by regulator if applied for permission. A critical change was shared only among the frontline workers as a practice, which caused the accident when workers attempted to manufacture a highly enriched product. It was a typical organizational failure as widely recognized. It can also be seen as a typical example of accidents caused by changes that were invented to satisfy a required quality standard in shorter time. It benefitted the workers in terms of shortening the work time in an adverse work conditions imposed by formal but tedious operating procedures. The traditional view of increasing the productivity for economic reason was not the issue there. How to make the system resilient by stopping such changes, which potentially challenge the defense-in-depth but are made tacitly under the name of continuous improvement, is an important issue.