1. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 1 Improving Feedwater Regulation Performance Using a System Based Approach FW Systems User’s group San Antonio, TX February 24 th, 2011 Eric Ascoli Senior Process Consultant

2. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 2 Key Take-aways Successful FW reg performance is defined as very stable SG level with a robust system that reacts well to transients and keeps the plant on line. While delivering that performance, does not over-cycle and wear the valve components out Successful FW reg performance is dependent on getting a number of things right –Valve characteristic need to match the pump curve to provide constant gain across the operating range –The actuator/valve assembly needs to operate smoothly and be able to stroke fast enough to meet system dynamics –The valve positioner needs to be able to provide quick but stable response, and be capable of filtering input, and impacting the gain of the valve assembly to keep the gain relatively constant over the operating range –The tuning parameters for water flow, steam flow, and steam generator level all need to be tuned to optimum levels (and usually aren’t due to legacy settings) There is a systematic approach to addressing these elements and improving performance that has already worked at a number of plants Still just scratching the surface in the nuclear industry

3. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 3 Experience to date with Nuclear-Last 6 years We’ve worked on multiple systems in ~20 reactors in North America Most of this work has been centered on heater drains and FW reg systems In nearly every case, we’ve seen multiple problems contributing to the performance issues reported: –Valves –Positioners –Tuning Very often the legacy tuning settings are outdated and actually contribute to instability Lambda tuning is all alternate approach that generally works better then the legacy tuning approach

4. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 4 Valve performance issues Trim characteristic should match the pump curve to keep gain as constant as possible over the operating range If not, one can’t tune for entire range and the system either ends up too hot or sluggish or both, as you vary the position Most valves do not fit system requirements very well Many valves have high friction due to trim problems or graphite packing and both contribute to poor valve response Some valve trims are unstable, which also causes problems with system stability-can be engineered away with the right mod’s Some valves are not fast enough/stable enough to provide good stable steam generator level-actuator undersized, air flow restrictions Changes to trim to better match system requirements and to improve stability can be a good investment Need to really pay attention to friction in trim and packing to boost performance

5. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 5 Valve Positioner/Accessories Analog positioners are limited in flow capacity and tuning capabilities Adding boosters/quick releases to speed up performance can introduce other failure modes and cause the valve to be unstable Digital devices generally operate more quickly and provide proper response without adding other devices to speed up stroking time They can also be tuned to help adjust the valve assembly response to match the system requirements, providing constant gain Some have input filters that can help stabilize the valve even further if there's noise on the input channel Digital upgrades will generally improve performance and this approach has proven itself at a number of reactors sites already

6. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 6 Tuning discussion Many nuclear plants use legacy tuning settings and don’t change because of concerns about increasing instability Many systems do not operate very well in terms of stability and reactions to transients Many plants employ work-arounds to insure system stability Based on our experience in actually testing systems over the last 5 years, we can model these systems and show how changes in valve and positioner performance and tuning can improve performance What-ifs can be checked out and recommendations made without disturbing the system on line Lambda tuning approach is used and nearly always improves performance over the legacy settings

7. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 7 How does this approach work Starts with a performance study on a given system Interview operators, look at overall system performance Observe reactions to changes in input Review valve characteristic vs. system performance Look at valve step response, and frictional characteristics Either conduct bump tests on line, or simulate the system in a computerized model and evaluate in terms of overall response Make prioritized recommendations for corrective action with estimated impact on performance RESULTS: Nearly always see big improvement in stability with fewer workarounds and more stable operation, which cuts down on maintenance needs for the given system

8. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 8 Plants who’ve successfully used this approach Pilgrim: heaters and FW reg’s Fort Calhoun: heaters Duane Arnold: heaters, condensate drains, moisture separators Wolf Creek: Let down pressure, and temp control systems Millstone: Heaters and spill valves SONGS: heaters Byron: FW reg valves and steam generator levels St. Lucie: FW flow stability, and steam generator level OPG-Pickering: Primary heat transfer feed valves Oconee #3: heater drains TMI #1: 6 th stage drain tank Beaver Valley: heater drains

9. 1st Qtr Results and Outlook/ 1.20.11 / Confidential KGM / 9 More plant experience Turkey Point #3 & #4: FW reg valve stability and steam generator level Turkey Point #3 & #4: heater drains Cooper #1: heater drains Calvert Cliffs #1: reactor let-down controls Point Beach #1: heater drains Clinton #1: feedwater flow and reactor level Kewanee: reactor level and FW flow Cooper #1: feedwater heaters Brunswick #2: de-aerator and heater drain SONGS: heaters and drain valves Diablo Canyon: FW flow control Nine Mile Point: heater drains Turkey Point #3 & #4: low pressure heaters