COMPUTATIONAL FLUID DYNAMICS MODELING APPROACH TO EVALUATE VSC – 17 DRY STORAGE CASK THERMAL
A numerical simulation of flow and heat transfer in a ventilated concrete dry storage cask system–17 (VSC–17) is performed and results compared with experimental data to assess the validity of the computational approach. The measurements of steady state temperature distributions on the cask surface, concrete surface, air flow channels, and fuel canister guide are available. Numerical simulations were carried out for normal operating conditions, where both the inlet and outlet vents are open, and for off-normal condition when normal air circulation is interrupted because of blocked vents. Results include the flow and temperature pattern in the ventilated storage system. Computed results were compared with experimental data for axial temperature distribution along the fuel assembly and radial temperature distribution along the storage assembly system. The effect of the turbulence model on temperature distribution pattern was also studied. For all the simulated cases, the computed results showed a trend similar to the experimental observation but did not model exactly. Computed peak cladding temperature in all the simulation cases was slightly higher than the experimental data. Heat transfer results showed some variation due to difference in backfill gas. A study of different k-ε and k-ω turbulence models showed very little effect on temperature distribution.
Thermal hydraulic analysis compared with tests of full-scale concrete casks
Abstract To develop a thermal analysis method for the concrete cask, numerical calculation based on thermal hydraulic phenomena was performed. In the present calculation model, calculation area was divided into two parts. One is inside of the canister and the other is outside of the canister. These two parts were combined at the surface of the canister. In the model of the outside, k – ɛ turbulence model was adopted for air flow region. Comparing calculation results with test results, it was found that the analysis method was valid for normal and accident conditions of the storage.
Community refinement of glaucoma referrals
AbstractAim To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS.Methods Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patient's GP was informed in all cases.Results The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately £17 per patient.Conclusion Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.