ABWR vessel sets record for weight, power, approval

The 890-ton reactor pressure vessel has been installed in Unit 6 of Tokyo Electric Power Co.`s (TEPCO) advanced nuclear boiling water reactor (ABWR) at Kashiwazaki-Kariwa nuclear power station.

“The reactor vessel is record-setting in several ways,” said Dr. Daniel R. Wilkins, GE`s Nuclear Services and Projects Department general manager. “Besides its weight–nearly four times heavier than the Statue of Liberty–the vessel has other impressive dimensions.” Its length from the bottom head to the vessel`s flange is 60 feet. Adding the vessel`s top head would bring its height to 74 feet. The inside diameter is 23.5 feet.

Unit 6, scheduled to enter operation in 1996, is the first of two advanced reactors being built on the TEPCO system. Unit 7 should begin operation in 1997. Both are 1,300-MW reactors.

The physical appearance of the advanced vessel differs from earlier BWR pressure vessels. Motor cases for the internal pumps are visible around the base of the ABWR vessel. These pumps replace external recirculation loops found on earlier models. Also, the vessel has no large nozzles below the core`s top, simplifying safety analysis and decreasing the possibility of core damage during hypothetical loss-of-coolant events.

The vessel, manufactured at the Ishi-kawajima-Harima Heavy Industries Co. in Yokohama, Japan, underwent 252 inspections during its 33-month construction.

Units 6 and 7 are being supplied by a consortium of GE`s Technical Services Co., Hitachi and Toshiba. GE was selected to supply the nuclear reactor systems, nuclear fuel and turbine generators.

The ABWR has been adopted as the next generation standard in Japan, with several utilities planning to construct additional units.

The ABWR is also a pacesetter in the United States, receiving the first final design approval from the US Nuclear Regulatory Commission for an advanced nuclear plant, which culminated a seven-year effort by GE and the US government to approve standardized nuclear reactor designs for future use.