John Day Dam Generator Water Cooling System Rehab   4

***31 October 2024*** Amendment 0005 - The purpose of this amendment is to provide revised specifications SECTION 40 95 00.00 26. Sections that were amended are 2.4.3 and 2.8. The sollicitation due date and time has also been revised to 11:00 A.M. on 13-NOV-2024

***29 October 2024*** Amendment 0004 - The purpose of this amendment is to provide revised specifications and draw ings f rom questions asked through bidder inquiries.

***21 October 2024*** Amendment 0003 - The purpose of this Amendment is to provide requested Resource Drawings

***03 October 2024 *** Amendments 0001 and 0002 have been posted to the solicitation. Please see admendments for details.

The U.S. Army Corps of Engineers (USACE) Portland District is soliciting a Contract for the John Day Generator Cooling Water System Rehab at John Day Dam, Rufus, Oregon. The proposed project will be a competitive, firm-fixed price (FFP) contract.

Project Scope: The U.S. Army Corps of Engineers, Portland District, has a requirement to replace generator air cooler, header and drain piping. The work also includes the installation of modulating valves and associated controls to generator air cooler and thrust bearing discharge heard lines as well as replacing existing flow gauges for the generator air coolers and thrust bearing coolers with ultrasonic or electromagnetic technology. The described work is to be conducted on 16 units.

Background: The John Day Powerhouse is located on the Columbia River, 112 miles east of Portland, Oregon, and is the third largest hydro-electric facility in the United States, with its 16 generators having a total capacity of 2408MW. The powerhouse lies on the border between Oregon and Washington. Units 1 to 14 are in Oregon while Units 15 and 16 are in Washington. This project is being performed to prevent or reduce water infiltration into the main unit generator windings to eliminate future failures. Since 2014, three main unit generators at John Day Powerhouse have experienced winding failures on startup that have been linked back to water infiltration into the generator windings. The purpose of this project is to minimize water leaks in the generator barrel, reduce condensation and improve water drainage. Water leaks from the generator air cooler vent pipes will be eliminated by replacing the problematic 1 2 inch overhead copper piping. This piping will be replaced with stainless tubing using compression or flared type connections. Soldered connections directly over the air coolers will be replace with flexible hose. This will reduce possible leak points and eliminate vent port alignment issues when swapping out coolers. The main units were designed without modulating or automatic shut off valves, despite modulating valves being standard on other government dams at time of John Day construction. Condensation will be reduced by adding modulation valves to the generator air cooler and thrust bearing oil cooler water discharge. Also, discharge flow meters will be replaced with new to eliminate the costly calibration issues with the existing devices. These modulating valves and flow meters will require associated controls and PLCs to integrate into the existing DDC system.

Contract Period of Performance: The estimated Period of Performance for this contract is 742 days after Notice to Proceed

Magnitude of Construction: The estimated cost of the project is $5,000,000 to $10,000,000.

Please see attached.