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Reliability of the Solar One plant during the power production phase: August 1, 1984--July 31, 1987

Description: The power production phase at Solar One spanned three years from August 1, 1984 through July 31, 1987. In that period the plant achieved an average availability, during hours of sunshine, of 81.7%. This report presents the frequencies and causes of the plant outages that occurred. The eleven most important causes composed 75% of the total outage time. Qualitative insights related to the origin and mitigation of these causes are provided. Also presented are insights and statistics regarding the reliability of the heliostat field. The quantitative and qualitative information presented in this report will be useful to studies aimed at improving the reliability of future solar central receiver power plants. 20 refs., 11 figs., 3 tabs.
Date: October 1, 1988
Creator: Kolb, G.J. & Lopez, C.W.
Partner: UNT Libraries Government Documents Department

Environmentally assisted cracking in light water reactors

Description: Research during the past year focused on (1) stress corrosion cracking (SCC) of austentitic stainless steels (SS), (2) fatigue of Type 316NG SS, and (3) SCC of ferritic steels used in reactor piping, pressure vessels, and steam generators. Stress corrosion cracking studies on austentitic SS explored the critical strains required for crack initiation, the effects of crevice conditions on SCC susceptibility, heat-to-heat variations in SCC susceptibility of Type 316NG and modified Type 347 SS, the effect of heat treatment on the susceptibility of Type 347 SS, threshold stress intensity values for crack growth in Type 316NG SS, and the effects of cuprous ion and several organic salts on the SCC of sensitized Type 304 SS. Crevice conditions were observed to strongly promote SCC. Significant heat-to-heat variations were observed in SCC susceptibility of Types 316NG and 347 SS. No correlation was found between SCC behavior and minor variations in chemical composition. A significant effect of heat treatment was observed in Type 347 SS. A heat that was extremely resistant to SCC after heat treatment at 650/degree/C for 24 h was susceptible to transgranular stress corrosion cracking (TGSCC) in the solution-annealed condition. Although there was no sensitization in either condition, the presence or absence of precipitates and differences in precipitate morphology appear to influence the SCC behavior. 20 refs., 20 figs., 11 tabs.
Date: October 1, 1988
Creator: Shack, W.J.; Kassner, T.F.; Maiya, P.S.; Park, J.Y. & Ruther, W.E.
Partner: UNT Libraries Government Documents Department

Thermal-hydraulic response and iodine transport during a steam generator tube rupture

Description: Recent reanalyses of the offsite dose consequences following a steam generator tube rupture have identified a possible non-conservatism in original FSAR analyses. Post-trip uncovery of the top of the steam generator U-tubes, in conjunction with a break near the U-tube top, could lead to increased iodine release due to a reduced ''scrubbing'' of the iodine in the primary break fluid by the steam generator secondary liquid. To evaluate this issue, analyses were performed at the Idaho National Engineering Laboratory. The RELAP5 computer code was used to conduct an analysis of the Surry plant to determine whether the post-trip steam generator secondary mixture level was sufficient to maintain continuous coverage of the U-tubes. The results indicated continuous coverage of the U-tubes. The RELAP5 result was supported by a hand calculation. Additional RELAP5 analyses were conducted to determine magnitudes of iodine release for a steam generator tube rupture. Two sensitivity studies were conducted. The amount of iodine released to the atmosphere was strongly dependent on the assumed value of the partition coefficient. The assumption of steam generator U-tube uncovery, on a collapsed liquid level basis, following reactor trip had a minor effect on the amount of released iodine. 17 refs., 28 figs., 5 tabs.
Date: October 1, 1988
Creator: Callow, R.A.
Partner: UNT Libraries Government Documents Department