Chubu to sue Hitachi for replacement fuel costs
Japan's Chubu Electric Power Co will file a lawsuit against Hitachi, seeking compensation for fuel costs after problems with a Hitachi-made turbine forced the shutdown of its Hamaoka 5 nuclear power reactor.
Japan's Chubu Electric Power Co will file a lawsuit against Hitachi, seeking compensation for fuel costs after problems with a Hitachi-made turbine forced the shutdown of its Hamaoka 5 nuclear power reactor.
In June 2006, a malfunction occurred in the low-pressure steam turbine of the 1267 MWe unit. The reactor automatically shut down due when abnormal vibrations were detected and a subsequent inspection revealed that the turbine's blades had broken. The turbine had been designed and manufactured by Hitachi.
Damage was found in 663 out of 840 of the moving blades on the 12th stage of the low-pressure turbine. One of the blades was found to be fractured. Investigations suggested that unanticipated vibration during test operations had caused metal fatigue that led to cracks at the base of the blades, which progressively worsened.
Hitachi conducted inspections and initial repairs at the two reactors. Chubu restarted Hamaoka 5 in March 2007. Hitachi has since redesigned and manufactured its turbine blades so that they can withstand high vibration levels.
In October 2007, Hitachi agreed to pay the entire costs of repairing the faulty turbines that caused the unplanned stoppage. At the time, the company said that it was continuing talks with Chubu about the higher oil and other fossil fuel costs that Chubu had incurred at its thermal power plants in compensating for the lost output from Hamaoka 5.
However, after failing to reach agreement with Hitachi, Chubu is now set to sue the company for some $390 million. Chubu plans to file the lawsuit with the Tokyo District Court within a week, according to spokesman Shuichi Terada. Hitachi said in a statement that it will examine details of the lawsuit before responding.
As an interim measure to respond to the damage, pressure plates were fitted in the 12th stages of the three low-pressure turbines at Hamaoka 5. However, as a long-term response, Chubu has proceeded with the design of new vanes to replace the damaged vanes. The structure of the new vanes was designed to reduce the vibrational stress on the connectors at the base of the vanes. In May 2008, Chubu said that tests and analyses related to the design of the new vanes had been completed and preparations have been made for their manufacture. Work plans concerning the vanes have been submitted to the Ministry of Economy, Trade and Industry.
When the required inspection period has elapsed, Chubu plans to commence manufacturing vanes and shafts for the 12th stages of the turbines according to the submitted plans. The vanes are to be replaced during the periodic inspection after the next periodic inspection (scheduled for late 2009). Chubu also intends to replace vanes in other stages with newly manufactured vanes.
