[en] This sourcebook presents current information on the measurement of the corrosion potential of stainless steel in boiling water reactors. The report describes the kinds of electrodes that have been used for the measurement and discusses the location for in plant measurements that will best represent the corrosion potential of components to be protected against stress corrosion cracking 68 refs., 28 figs., 9 tabs

[en] The objectives of this project are to acquire operational data as to steam generator performance world-wide and to store that data in such fashion as to provide for statistical analysis. Such analysis is expected to lead to correlations between plant chemistry and operating considerations, on the one hand, and steam-generator damage progression (or notable lack thereof) on the other hand. In turn, such correlations will provide a basis for recommendations intended to reduce or prevent future steam-generator degradation. Questionnaires have been prepared and transmitted. Plant information is gradually being reviewed. The computer and compatible computational tools for data storage, access, and analysis have been established. Considerable data have been stored and computational techniques are being tried out. The report provides details on this process which will ultimately be developed into a User's Manual for those who may ultimately make use of the data base when completed

[en] Sea water impurities hide out within thin (∼10 microm) deposits on steam generator tubes, as demonstrated by both laboratory studies using segments of fouled steam generator tubes pulled in 1992 from Crystal River-3 nuclear power station, and field hideout return studies performed during recent plant shutdowns. Laboratory tests performed at 279 C (534 F) and heat fluxes ranging from 35 to 114 kW/m² (11,100--36,150 Btu/h.ft²), conditions typical of the lower tubesheet to the first support plate region of a once-through steam generator, showed that impurity hideout can occur in thin free-span tube deposits. The extent of hideout increased with increasing heat flux. Soluble species, such as sodium and chloride ions, returned promptly to the bulk water from the deposits on turning the heat flux off, whereas less soluble species, such as calcium sulfate and magnesium hydroxide, returned more slowly. Recent field hideout return studies performed at Crystal River-3 in which the water level in the steam generators was maintained below the first tube support plate during the shutdown, thus wetting only the thin deposits in the free span and the small sludge pile, corroborate the laboratory findings, showing that hideout does indeed occur in the free-span regions of the tubes. These findings suggest that hideout within tube deposits has to be accounted for in the calculation of crevice chemistry from hideout return studies and in controlling the bulk chemistry using the molar ratio criterion

[en] Sea water impurities hide out within thin (∼10 μm) deposits on steam generator tubes, as demonstrated by both laboratory studies using segments of fouled steam generator tubes pulled in 1992 from Crystal River-3 nuclear power station and field hideout return studies performed during recent plant shutdowns. Laboratory tests performed at 279^oC (534^oF) and heat fluxes ranging from 35 to 114 kW/m² (11,100 - 36,150 Btu/h.ft²), conditions typical of the lower tubesheet to the first support plate region of a once-through steam generator, showed that impurity hideout can occur in thin free-span tube deposits. The extent of hideout increased with increasing heat flux. Soluble species, such as sodium and chloride ions, returned promptly to the bulk water from the deposits when the heat flux was turned off, whereas less soluble species, such as calcium sulfate and magnesium hydroxide, returned more slowly. Recent field hideout return studies performed at Crystal River-3 where the water level in the steam generators was maintained below the first tube support plate during the shutdown, thus wetting only the thin deposits in the free span and the small sludge pile, corroborate the laboratory findings, showing that hideout does indeed occur in the free-span regions of the tubes. These findings suggest that hideout within tube deposits has to be accounted for in the calculation of crevice chemistry from hideout return studies and in controlling the bulk chemistry using the molar ratio criterion. (author). 3 refs., 4 tabs., 3 figs

[en] Utilities have made—and continue to make—extensive efforts to reduce the rate at which iron-based corrosion products accumulate in PWR steam generators (e.g., amine optimization to reduce corrosion product transport and outage deposit removal strategies) to reduce susceptibility to stress corrosion cracking and to minimize negative impacts of corrosion product deposition on thermal performance. Even though these efforts have led to substantial improvements over the past two decades, there are practical lower limits on the feedwater iron concentration that can be achieved. Also, the substantial cost and limitations of cleaning techniques make deposit removal an imperfect solution. Dispersant application has emerged as a viable and effective technology for significantly reducing the corrosion product fouling rate in steam generators (SGs) and has also contributed to improvements in steam generator thermal performance. This paper will summarize the following work: An extensive effort to quantify the improvement in blowdown iron removal efficiency achieved at Exelon and South Texas Project (STP) units with online dispersant application. This work encompassed re-analysis of blowdown and feedwater corrosion product sample filters collected during several years of operation. A detailed evaluation of the improvements in SG thermal performance observed with online dispersant application at Exelon and STP units. A recently completed two-year monitoring and testing program to evaluate the performance of condensate polishing resin at STP 1 during online dispersant application. A summary of offline dispersant applications, i.e., addition during post-outage recirculation cleanup and SG wet layup. Perspectives on novel application strategies (e.g., targeted online addition at the end of the operating cycle and optimization of offline applications) will be provided. (author)

[en] Under EPRI sponsorship, an industry committee, similar in form and operation to other guideline committees, was created to develop Condensate Polishing Guidelines for both PWR and BWR systems. The committee reviewed the available utility and water treatment industry experience on system design and performance and incorporated operational and state-of-the-art information into document. These guidelines help utilities to optimize present condensate polisher designs as well as be a resource for retrofits or new construction. These guidelines present information that has not previously been presented in any consensus industry document. The committee generated guidelines that cover both deep bed and powdered resin systems as an integral part of the chemistry of PWR and BWR plants. The guidelines are separated into sections that deal with the basis for condensate polishing, system design, resin design and application, data management and performance and management responsibilities

[en] The first nuclear application of PAA dispersant to improve corrosion product removal during LPR (Long-path recirculation) cleanup occurred at Byron Unit 1 in spring 2011. The main conclusions and lessons learned are as follows: -) there were no significant problems with application of PAA during LPR with an initial PAA concentration of about 650 ppb; -) a reasonable estimate of the additional iron mass removed due to the presence of PAA is 5-9 kg. The qualification work, application details and an assessment of the results are the first focus of this paper. The second part of this paper summarizes the online experience to date at the Exelon and STP (South Texas Project) plants on the effects of dispersant on -) blowdown iron removal efficiency, -) steam generator heat transfer efficiency and -) ion exchange resin performance

[en] Water chemistry control technologies for nuclear power plants have been significantly enhanced over the past few decades to improve material and equipment reliability and fuel performance, and to minimize radionuclide production and transport. Chemistry Guidelines have been developed by the Electric Power Research Institute (EPRI) for current operating plants and have been intermittently revised over the past twenty-five years for the protection of systems and components and for radiation management. As new plants are being designed for improved safety and increased power production, it is important to ensure that the designs consider implementation of industry approved water chemistry controls. In parallel, the industry will need to consider and develop updated water chemistry guidelines as well as plant startup and operational strategies based on the advanced plant designs. In 2010, EPRI began to assess chemistry control strategies at advanced plants, based on the Design Control Documents (DCDs), Combined Construction and Operating License Applications (COLA), and operating experiences (where they exist) against current Water Chemistry Guidelines. Based on this assessment, differences between planned chemistry operations at new plants and the current Guidelines will be identified. This assessment will form the basis of future activities to address these differences. The project will also assess and provide, as feasible, water chemistry guidance for startup and hot functional testing of the new plants. EPRI will initially assess the GE-Hitachi/Toshiba ABWR and the Westinghouse AP1000 designs. EPRI subsequently plans to assess other plant designs such as the AREVA U.S. EPR, Mitsubishi Heavy Industries (MHI) U.S. APWR, and GE-Hitachi (GE-H) ESBWR. This paper discusses the 2010 assessments of the ABWR and AP1000. (author)

[en] Under EPRI sponsorship, an industry committee, similar in form and operation to other guidelines committees, was created to develop PWR shutdown and startup chemistry recommendations. The committee reviewed the available data and determined that there was justification for a chemistry guideline in this area, since a coordinated shutdown program could help avoid some of the problems that had been reported. Though reduced radiation fields might be a long-term benefit of continued application of shutdown and startup chemistry, the committee determined that data were not available to propose that as a goal. These guidelines present a series of principles to optimize a shutdown and startup strategy for both refueling and mid-cycle shutdowns. The principles reflect general guidance to ensure cooldown under reducing conditions, avoid increasing pH, maximize cleanup and, finally, establish an oxidizing environment. Consistent with other guidelines documents, these guidelines also present technical bases, analytical methods and data evaluation techniques. Current plans are to combine these recommendations with the PWR Primary Water Chemistry Guidelines during the Revision 3 process, scheduled for 1995

[en] An effective, state-of-the art secondary water chemistry control program is essential to maximize the availability and operating life of major PWR components. Furthermore, the costs related to maintaining secondary water chemistry will likely be less than the repair or replacement of steam generators or large turbine rotors, with resulting outages taken into account. The revised PWR secondary water chemistry guidelines in this report represent the latest field and laboratory data on steam generator corrosion phenomena. This document supersedes Interim PWR Secondary Water Chemistry Recommendations for IGA/SCC Control (EPRI report TR-101230) as well as PWR Secondary Water Chemistry Guidelines--Revision 2 (NP-6239)