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Condensate Polishing... Continued from page 38 been reduced in excess of 50% since the deployment of amine form operations. Most people consider safety with regard to plant personnel and equipment; an additional consideration is safety of the environment. The renaissance of nuclear power can be attributed, at least in part, to its safe and effi cient production of electricity. Another component to its resurgence is the minimal environmental impact nuclear power has in its product generation. Millstone’s innovation in condensate polisher operations reduces station water usage by almost 16,000,000 gallons per year; 16,000,000 gallons of a vital natural resource not used performing unnecessary regenerations. In addition to the reduced water usage, fewer regenerations produce less chemical waste, which are subsequently discharged to the environment. A key initiative in the State of Connecticut is a reduction in the nitrogen loading to Long Island Sound. Amine form operations support this initiative by reducing Millstone’s nitrogen loading to Long Island Sound by almost 20,000 Kg/year. Improved equipment reliability, reduced personnel exposure to hazardous chemicals and less environmental impact, all point to the improved safety aspects of amine form operations. Radiation Protection Savings is 10- 50 person-rem. Ongoing Savings (recurring) is 10 to 15 Rem Per 36 Month Cycle. Life of Plant savings is 100 to 150 Rem. Cost Savings Impact: The biggest single saving is that associated with chemical purchases. Amine operations enhance the effi ciency of condensate polishing by not removing secondary pH control chemicals and subsequently requiring less resin regenerations. Each polisher operated in the amine form is estimated to produce annual savings of almost $70,000. With seven polishers in the amine form at Millstone this equates to an annual savings of almost $500,000 each year. As the cost for chemicals con- tinues to climb, these savings will only increase in the future. The reduction in regenerations saves substantial non-outage labor hours. These savings refl ect reduced regenerations, discharges and bulk chemical delivery support. It is calculated that by having the seven amine charges in service at the station, over 3,000 person hours per year have been able to be redirected to the performance of other tasks. A careful review was recently conducted to ascertain the feasibility of reducing steam generator sludge lancing and upper bundle fl ush frequency. A decrease in corrosion product transport was key to the conclusion to reduce these activities to a 36 month performance cycle. Omission of this activity saves in excess of $1,000,000 per refueling outage. This performance frequency reduction would not be possible without the elevated pH allowed by utilizing amine operations. A key expense of any outage is piping replacement due to fl ow-accelerated corrosion. Amine operations and the resulting increase in secondary pH have had a positive impact on reducing the corrosion of secondary components. The station has observed a decreasing trend in secondary wear rates and a marked increase in the life of secondary components, exceeding initial life expectancy of many parts of the secondary plant. The savings from reduced corrosion are enormous and include the materials and labor saved performing component replacement and repair. The cost of constructing staging, the impact of radiography on surrounding work activities, and the ability to mitigate the impact of expanded scope to a refueling outage also factor into this assessment. Innovation: First PWR with recirculating steam generators in the world to operate full fl ow condensate polishing in the amine form. Deep bed condensate polishing ion exchangers have typically been utilized in the industry for the purpose of providing protection to the steam generators in the event of a leak of the ultimate heat sink into the main condensate fl uid. The resins used in these polishers – normally a one-to-one equivalent mixture of strong acid cation and strong base anion – have traditionally been operated in the H-OH form. That is, with a hydrogen ion (H+) attached to the cation resin’s sulfonic functional group, and a hydroxide ion (OH-) attached to the anion resin’s amine functional group. Any ingress of salt contaminants, e.g., sodium chloride, or sodium sulfate, would be adsorbed by the stationary phase of the resins and be replaced in the liquid phase by an equivalent amount of water. One of the drawbacks to H-OH polisher operation is that the resins are unable to distinguish between undesirable chemicals in solution and those intentionally injected for the purpose of secondary cycle pH control. For example, ethanolamine, a volatile, weak base used by many utilities, is completely ionized by the strongly acidic and basic resins, removed from the liquid phase, and replaced by water. This requires a continuous injection of ethanolamine at the polisher outlet to replace the adsorbed chemical. Furthermore, since the IX resins exhibit a higher selectivity for the secondary cycle amine than for the salts, it is common practice to remove the polisher from service when the stationary phase becomes saturated with the amine. The cation resin is then regenerated with sulfuric acid, restoring the (H+) inventory to the functional groups, and placing it in the presumed most optimum condition for salt removal. This results in the generation of appreciable amounts of nitrogen-bearing wastewater. In the absence of condenser in-leakage, most of the load on the anion resin comes from bicarbonate and carbonate ions originating from carbon dioxide dissolved in the main condensate. The relatively low concentration of these compounds allows utilities to skip anion resin regenerations; typically, one anion resin regeneration is performed for every ten cation resin regeneration cycles. Even so, the chemical used for anion resin regeneration – sodium hydroxide – is used to neutralize the acidic wastewater resulting from the cation resin regeneration. Besides the large chemical demand and wastewater generation and processing costs, H-OH form operation of the condensate polishers places a ceiling on the allowable concentration of the secondary cycle pH-controlling agent and, ultimately, on a utility’s ability to minimize the generation and transport 40 www.nuclearplantjournal.com Nuclear Plant Journal, March-April 2009
of balance-of-plant corrosion products. This ceiling results from the logistical limitations of maintaining hundreds of cubic feet of ion exchange resins with a fi xed total exchange capacity, deployed in numerous polisher vessels, in the requisite H-OH chemical form. Millstone Chemistry determined that the problem could only be addressed by resolving the competing goals of high secondary pH and H-OH form condensate polisher operations. Millstone conducted bench top testing to determine if operating the condensate polishers in the amine (ETA) form might be a viable option. A mixed bed test column was set up for the purpose of evaluating the performance of DOW 650C cation resin that had been converted to the amine form, along with 550A anion resin in the conventional OHform, during a simulated seawater leak. Implementation of this experiment required questioning the standard industry practice that selectivity is the dominant ion exchange mechanism between the liquid phase (condensate) and the solid phase (resin). Successful completion of this test would require displacement to Confi dent to... Continued from page 27 • Implementing low Cobalt 316 LN for the Primary Loop Piping, thus mitigating potential (IGSCC and TGSCC) issues as well as reducing Man Rem exposures during maintenance outages • Implementing single piece forging technology for the hot leg with side nozzles to eliminate welds and inservice inspections • Implementing chrome- moly- and copper-containing steel grades in the Main Steam Piping, mitigating potential Flow Assisted Corrosion in the steam piping The AP1000 component design, material selection, fabrication processes factor in lessons learned from operating experience, best practices and knowledge from industry materials research programs. Because of these factors, Westinghouse has confi dence that the AP1000 will deliver reliable performance of com- be considered the dominant exchange mechanism, not selectivity. The bench top test was successful in proving that amine form resin would provide the same level of protection to the steam generators from seawater ingress as the conventional H+ OH form resins. This successful testing shattered all previous beliefs and paved the way for this innovation in condensate polishing operations. Productivity/Effi ciency: The advantages of amine operations go well beyond cost savings, safety improvements and less environmental impact, as it also allows for greater operational fl exibility. While traditional H-OH charges required a cation regeneration approximately every forty million gallons and an anion regeneration approximately every fi ve hundred million gallons, amine charges merely require a mechanical cleaning every two to three billion gallons. Imagine the operational fl exibility associated with decreasing the need to perform work on a resin charge from approximately ev- ponents in the next generation of nuclear power plants. 9. What are recommended practices for reactor pressure vessel in-service inspection to ensure that: a. Entire thickness of the reactor pressure vessel is inspected from different angles. The regulatory requirements for reactor pressure vessel in-service inspection mandate that only the welds and a defi ned amount of adjacent base metal be examined. Such examinations are volumetric (ultrasonic testing) and include the entire thickness. The examinations are conducted from the inner diameter surface of the reactor vessel and are designed to examine the full thickness in thickness zones. Different angles and techniques are defi ned for each zone. b. Nozzles and their associated welds are checked Nozzle-to-shell welds, nozzle innerradius regions and nozzle-to-pipe welds are examined in accordance with regulatory requirements. ery ten days to approximately every two years. Using all H-OH demineralizers Millstone was regenerating each charge on a ten day rotation; this meant one regeneration needed to be performed every thirty six hours. With the advent of amine operations we now have the luxury of not working certain resin charges for almost a two year period. This allows for the fl exibility to perform almost all corrective and preventative maintenance on-line, thereby reducing the impact and need for valuable resources to be used during outage periods. In addition, this reduction in regenerations reduces the operator time spent in the condensate polishing facility (CPF). Millstone has seen an almost 40% reduction in operator time required to support daily CPF operations. Contact: Lewis Crone, Millstone Power Station, Chemistry Department 465/5, Rope Ferry Road, Waterford, CT 03685; telephone: (860) 444-5722, email: Lewis.E.Crone@dom.com. � c. Detecting fl aws in the welds in the reactor pressure vessel. Due to the safety importance of reactor pressure vessel welds, requirements dictate that the examination methods provide a high degree of reliability. To ensure this reliability, the examination procedures are required to undergo blind performance demonstration tests proctored by a third-party organization. Such tests involve representative component mockups containing implanted defects that are representative of postulated defects. The procedures must be demonstrated to detect 100 percent of the critical defects. Once the procedure is demonstrated, then ultrasonic test personnel who are responsible for the examination must also undergo blind testing using the same set of mockups. Blind testing means that the defect population within the mock-ups remains unknown to the participants. This performance demonstration protocol ensures a higher integrity of examinations. Contact: Scott Shaw, Westinghouse Nuclear, 4350 Northern Pike, Monroeville, PA 15146, telephone: (412) 374-6737, email: shawsa@westinghouse.com. � Nuclear Plant Journal, March-April 2009 www.nuclearplantjournal.com 41
Page 1 and 2: Nuclear Plant Journal Plant Mainten
Page 3 and 4: WITH PHASED ARRAY YOU HAVE TO BE HI
Page 5 and 6: Nuclear Plant Journal March-April 2
Page 7 and 8: HIGH MAINTENANCE Even if everything
Page 9 and 10: Utility, Industry & Corporation Uti
Page 11 and 12: New Products, Services & Contracts
Page 13 and 14: We look at power plant maintenance
Page 15 and 16: Meeting & Training Calendar 1. 9 th
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Page 25 and 26: Valtimet sales offices for Welded T
Page 27 and 28: In-service inspections to some degr
Page 29 and 30: location. All systems interface wit
Page 32 and 33: Designed for Optimum Production By
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Page 37 and 38: One of the key conclusions of the D
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Page 43 and 44: NPJ-SBU-0908 Machining, re-imagined
Page 45 and 46: Minimizing Radiological Effl uent R
Page 47 and 48: Radiation-101, An Internet-Based Co
Page 49 and 50: Community outreach efforts To help
Page 51 and 52: WESTINGHOUSE HAS SOME simple ideas,

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