BWR 90—the advanced BWR of the 1990s

Abstract

The future global role of nuclear power will be determined by its ability to provide economical and safe energy. Nuclear power, like any other substantial contributor to the world's energy needs, must be generated at an acceptable cost and with negligible environmental effects. Besides, it must achieve and maintain a socially reasonable level of public acceptance, which in turn is not necessarily governed by rational assessments of the true safety and environmental impact of nuclear power. The ABB Atom approach to this situation can best be characterized as a `cautious evolution'; for the next decade the company will largely base its offerings to the market on its `evolutionary' light water reactor design, the BWR 90. This design builds closely on the experience from successful construction and operation of its predecessor, the BWR 75 design. In 1995 and 1996, plants of this design achieved an average load factor greater than the 87% set by EUR; the two BWR units at Olkiluoto in Finland are among the very best performing plants in the world, with an average load factor of 94% over the last 7 years. The continued LWR design development focuses on meeting requirements from utilities as well as new regulatory requirements. A particular emphasis is put on the consequences of severe accidents; there shall be no large releases to the environment. Other design improvements involve: all-digital I and C systems and enhanced human factors engineering to improve work environment for operators, optimization of buildings and containment design to decrease construction time and costs, and selection of materials as well as maintenance and operating procedures to even further reduce occupational radiation exposures. Probabilistic safety assessments and life-cycle cost evaluations have become major tools in the design optimization work. The BWR 90 was offered to Finland in the early 1990s, and will now as the first BWR design be reviewed by a number of European utilities with respect to its conformance to the European Utility Requirements (EUR); a specific EUR Volume 3 for the BWR 90 will be the final result. The paper describes some of the unique characteristics of the BWR 90, with emphasis on the features that are most important for achieving improved economy and enhanced safety.