Shutdown at unit Oskarshamn 1 after a record long operating period

Pressrelease Wednesday, March 25, 2015

After a record long operating period without any interruptions, unit Oskarshamn 1 (O1) suffered an operational disturbance on Monday 23 March. The disturbance began only two days before a planned shutdown was about to start in order to correct a water leak in the facility's fuel preheating system. Since the annual maintenance outage is about to start this following Easter, it has been decided that the unit will not be restarted until after the work has been completed on 22 May.

A level displacement in a water cistern in the hydraulic system for the control rod drives at Oskarshamn 1 (O1) resulted in that the operation was automatically shut down on Monday afternoon. The shutdown means that the more than forty-year old unit's new record of electricity deliveries without disturbances came to a halt at 303 days.

- Since the failure in the hydraulic system has been corrected, replacement of several gaskets in the fuel preheating system will now be conducted to remedy the water leak, says production manager Mats Ekblad. After that work is completed, we will prepare ourselves for the annual maintenance work which will lead to a new and hopefully just as successful operating period starting on 22 May.

During the outage, the usual refuelling and test programmes will be performed. Among the major works to be performed are included replacements of check valves and pipe supports in the scram system, and service of the steam conduit.

- However, above all, we plan to conduct a thorough overhaul of the turbine equipment, so that we hereafter hopefully may have an operation without any vibrations, on a maximum capacity instead of operation on 94 per cent which has been the case during this past operating season, Mats Ekblad concludes.

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Page updated Wednesday, March 25, 2015