MSR retrofit to boost power for Kori units

Korean Electric Power Corp. has issued a contract to US-based Senior Engineering Co. for the redesign and in-situ reconstruction of four moisture-separator reheaters (MSR) for its 900-MW units 3 and 4 at the Kori Nuclear Power Plant near Pusan. With this project, Senior will have reconstructed MSRs on all four Kori units, which produce 3,000 MW of electric power.

The project is expected to restore at least 10 MW of power per unit and to greatly increase unit reliability. It will include complete replacement of both the reheater and MSR sections in the existing two-pass shells with an improved four-pass design. The new, high-performance MSRs will use stainless-steel-finned tubing in a wider, hexagonal field that more nearly matches the cylindrical shape of the existing MSR shells, greatly reducing steam bypassing. This way more tubes can be used to reduce the pressure drop and increase the rate of heat transfer. Also, tube support plates will be of the slip-plate design to drastically reduce the damaging effects of variable thermal stressing. The moisture-separator section in the MSRs will use double-pocket, chevron-type moisture collectors and other improvements to the decade-old original equipment to increase moisture-separation efficiency to nearly 100 percent.