A new report has just been developed on the Mark I containment design that is in use at the Fukushima Daiichi nuclear power plant. It also explores U.S. and regulatory actions that made the design safer over the past several decades, noting “the Mark I pressure suppression containment is a proven technology that has been enhanced with confirmatory testing, enhanced knowledge and advanced analysis over time.”
In addition to explaining the boiling water reactor (BWR) design, the report, which can be downloaded from the Nuclear Energy Institute website, also makes initial observations about the performance of the containment system at Fukushima.
- “Coincident long-term loss of both on-site and off-site power for an extended period of time is a beyond-design-basis event for the primary containment on any operating nuclear power plant.”
- “The Mark I containment vessels appeared to have held pressure to well above the design pressure.”
- “The response of the reactor pressure vessel and reactor in general agree with severe accident management studies performed in the 1980s and early 1990s.”
Other topics in the report include: “Containment Operation During a Loss of Coolant Accident,” “Evolution of the Design,” and “Containment Operation During a Station Blackout.”
Regarding operation during a blackout, the report notes: “In the late 1980s and early 1990s, BWR operators made procedure changes and modifications to cope with events which involved the loss of the normal offsite power and normally available emergency diesel generators…. As a result of the September 11, 2001 terrorist attacks, additional actions and equipment were put in place at certain U.S. plants to allow water makeup to the reactor and the fuel pools should significant damage occur to the reactor buildings. These changes include pre-staged diesel-driven pumps, piping, and procedures that would support water makeup from various water supplies without the need for electrical power.”
Learn more in these GE Reports stories:
* Setting the Record Straight on Mark I Containment History
* Mark I Containment Facts and The New York Times
* The Mark I Containment System in BWR Reactors
* An Update on GE Disaster Relief Efforts in Japan
* Facts on the Nuclear Energy Situation in Japan (Update)
The NEI website is also providing updates on the situation in Japan.