Auxiliary feedwater-system reliability studies

The purpose of this paper is to describe the BNL review process applied to the reliability analyses of Auxiliary Feedwater Systems (AFWS) submitted by operating license applicants to NRC in order to satisfy the pertinent Standard Review Plan requirements. Some generic comments on the availability characteristics of the AFWS are also presented. This work represents an application of a quantitative reliability goal to the regulatory process

Fluctuations in two-dimensional six-vertex systems

The character of polarization correlations in six-vertex systems is discussed. With the aid of a connection between the 1-d Heisenberg--Ising chain and the six-vertex problem, existing results for the chain correlations are used to obtain information about long-wavelength polarization correlations in six-vertex models. These results are compared with a neutron scattering study of 2-d polarization correlations in the layered compound copper formate tetrahydrate. Because the six-vertex model is equivalent to a particular roughening model, these results also explicitly predict the critical behavior of that roughening model just above its roughening temperature. The results correspond to the predictions of Kosterlitz and Thouless for the phase transition in the 2-d Coulomb gas. 5 figures

Fine structure of the isoscalar giant quadrupole resonance in 40Ca due to Landau damping?

The fragmentation of the Isoscalar Giant Quadrupole Resonance (ISGQR) in 40Ca has been investigated in high energy-resolution experiments using proton inelastic scattering at E_p = 200 MeV. Fine structure is observed in the region of the ISGQR and its characteristic energy scales are extracted from the experimental data by means of a wavelet analysis. The experimental scales are well described by Random Phase Approximation (RPA) and second-RPA calculations with an effective interaction derived from a realistic nucleon-nucleon interaction by the Unitary Correlation Operator Method (UCOM). In these results characteristic scales are already present at the mean-field level pointing to their origination in Landau damping, in contrast to the findings in heavier nuclei and also to SRPA calculations for 40Ca based on phenomenological effective interactions, where fine structure is explained by the coupling to two-particle two-hole (2p-2h) states.Comment: Phys. Lett. B, in pres

Analysis of an unmitigated large break loss of coolant accident (LBLOCA) with the non-mechanistic failure of passive cooling for the APT Spallation Target

In order to support the Programmatic Environmental Impact Statement, an accident analysis has been performed for the Accelerator Production of Tritium (APT) Spallation-Induced Lithium Conversion (SILC) Source. This report presents a lumped-parameter analysis that predicts the thermal response of the source to a large-break LOCA. The accident scenario assumes the break to occur in the cold leg outside the source basin and the pipe break is immediately followed by the tripping of the proton beam and the activation of the source-basin flood system. The calculations were performed for a ``beyond-design-basis event`` which further assumes the failure of all other active cooling systems, and the failure to establish natural circulation in the unbroken loop. Calculations show that the source rods remain flooded in heavy water until 44 hours after the LOCA. At this time, the source rods begin to be uncovered and at 48 hours into the accident the source rods are completely boiled dry. The average source temperature reaches a maximum value of 303 C at 57 hours. Thereafter, the source rods begin to cool since the heat transfer to the basin water is sufficient to remove all the decay heat from the source. It is estimated that by this time a maximum of 27% of the lead inventory (6,558 kg) in the source rods can be expected to melt. This molten material, assuming that it can get out of the aluminum cladding, will fall to the D{sub 2}O-filled bottom header, quench rapidly, and remain in a coolable state

Fluid dynamic demonstrations for waste retrieval and treatment

The objective of this study was to develop or identify flow correlations for predicting the flow parameters needed for the design and operation of slurry pipeline systems for transporting radioactive waste of the type stored in the Hanford single-shell tanks and the type stored at the Oak Ridge National Laboratory (ORNL). This was done by studying the flow characteristics of simulated waste with rheological properties similar to those of the actual waste. Chemical simulants with rheological properties similar to those of the waste stored in the Hanford single-shell tanks were developed by Pacific Northwest Laboratories, and simulated waste with properties similar to those of ORNL waste was developed at ORNL for use in the tests. Rheological properties and flow characteristics of the simulated slurry were studied in a test loop in which the slurry was circulated through three pipeline viscometers (constructed of 1/2-, 3/4-, and 1-in. schedule 40 pipe) at flow rates up to 35 gal/min. Runs were made with ORNL simulated waste at 54 wt % to 65 wt % total solids and temperatures of 25{degree}C and 55{degree}C. Grinding was done prior to one run to study the effect of reduced particle size. Runs were made with simulated Hanfordmore » single-shell tank waste at approximately 43 wt % total solids and at temperatures of 25{degree}C and 50{degree}C. The rheology of simulated Hanford and ORNL waste supernatant liquid was also measured.« l