[en] This paper reports on boron carbide-boron nitride particulate composites that were fabricated by vacuum hot-pressing. Near-theoretical densities of B₄C were obtained, but percent theoretical densities decreased with increasing amounts of BN. The grain size of B₄C and BN was not affected by composition, but the amount of twinning in B₄C decreased with increasing BN content. No third phase was found at the B₄C-BN interface by analytical STEM analysis. Lattice parameter measurements indicated slight solubility of B₄C in BN, but no solubility of BN in B₄C for samples hot-pressed at 2250 degrees C. Room-temperature flexural strength measurements revealed a sharply decreasing strength with increasing BN content up to 40% BN, and then relatively constant values with greater amounts of BN

[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)