[en] This report describes the requantification of two existing fire probabilistic risk assessments (PRAs) using a fire PRA method and data that are being developed by the Electric Power Research Institute (EPRI). The two existing studies are the Seabrook Station Probabilistic Safety Assessment that was made in 1983 and the 1989 NUREG-1150 analysis of the Peach Bottom Plant. Except for the fire methods and data, the original assumptions were used. The results from the requantification show that there were excessive conservatisms in the original studies. The principal reason for a hundredfold reduction in the Peach Bottom core- damage frequency is the determination that no electrical cabinet fire in a switchgear room would damage both offsite power feeds. Past studies often overestimated the heat release from electrical cabinet fires. EPRI's electrical cabinet heat release rates are based on tests that were conducted for Sandia's fire research program. The rates are supported by the experience in the EPRI Fire Events Database for U.S. nuclear plants. Test data and fire event experience also removed excessive conservatisms in the Peach Bottom control and cable spreading rooms, and the Seabrook primary component cooling pump, turbine building relay and cable spreading rooms. The EPRI fire PRA method and data will show that there are excessive conservatisms in studies that were made for many plants and can benefit them accordingly

[en] Theory and experiment are being used together to explore spectra from sodium and xenon gas mixtures similar to those used in high pressure lamps. Results from high precision measurements of the absorption coefficients over the wavelength range from 425 to 760 nm are presented with 0.02 nm spectral resolution. Measurements of the sodium density with ±5 percent uncertainty complement the absorption coefficient measurements. The experimental data are compared to quantum-mechanical spectral calculations that utilize recent cold collision and other data. The spectra are sensitive to the interatomic potentials, especially in the far wings in which molecular features such as vibrational-rotational and satellite structures are exhibited. The particular results for Na-Xe are analyzed in detail