Mitsubishi delivers to San Onofre

24 February 2009

Two replacement steam generators have been delivered for the second unit of Southern California Edison's (SCE's) San Onofre Nuclear Generating Station (SONGS). Mitsubishi Heavy Industries (MHI) made the components.


A pristine new steam generator destined for SONGS 2
(Image: MHI)

The replacement steam generators arrived at the SONGS site on 14 February and are set to replace existing units at SONGS 2 during its next refuelling and maintenance outage, scheduled for the autumn. Later this year, MHI will ship two more to SCE for installation in SONGS unit 3 in the autumn of 2010.
MHI received the order from SCE in September 2004 after winning an international bidding competition. The steam generators were manufactured at the company's Kobe Shipyard & Machinery Works in Japan. The contract did not include installation work.
Steam generators are crucial components of plants based on pressurized water reactors (PWRs), transferring the thermal energy generated in the reactor vessel to the turbine generator by producing steam to drive the turbine.
The steam generators delivered are among the world's largest, each measuring approximately seven metres in external diameter, weighing 580 tonnes and housing approximately 10,000 heat transfer tubes.
There are two units at the SONGS plant, the 1070 MWe unit 2 and 1080 MWe unit 3, which entered service in 1983 and 1984, respectively. Replacement of the steam generators currently in use will enable the plant to continue operating up to 2022.
The components, having arrived in California from Japan by sea, were towed on a barge from the Port of Long Beach to a Camp Pendleton boat launch. From there, they were transported by road to the SONGS site. Edison has worked with 12 local, state and federal agencies since 2002 to coordinate the transport of the generators, a spokesman for SCE told the Orange County Register.
Since 1970, MHI has supplied steam generators to all of Japan's PWRs as well as to numerous PWRs in other countries, including replacement steam generators which the company notes help to extend plant operating life as well as boosting safety and efficiency. It is Japan's only steam generator manufacturer.
The company has processed overseas orders of 28 units, mainly from North America and Europe. The total reaches 122 units if steam generators and RSGs for the Japanese market are included.