Staffan Jacobsson

Fibrin sealant in prevention of flexor tendon adhesions : An experimental study in the rabbit

The effect of fibrin sealant on the development of adhesions in flexor tendon surgery was studied in both immobilized and active weight-bearing paws of rabbits. A partial laceration was produced and was treated with sutures alone or with both sutures and glue. Immobilized tendons treated in these ways showed no difference in adhesion formation, but in mobile tendons there was a difference at 6 weeks in gross appearance, scanning electron micrographic appearance, and strength of adhesions as measured when the distally cut tendon was pulled out of its sheath. These observations indicate that, after repair, a mobile flexor tendon heals with a smooth gliding surface and without formation of restricting adhesions when treated with fibrin glue around the suture site.

A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel Assemblies—II: Experimental Investigation

Abstract A tomographic method for verification of the integrity of used light water reactor fuel has been experimentally investigated. The method utilizes emitted gamma rays from fission products in the fuel rods. The radiation field is recorded in a large number of positions relative to the assembly, whereby the source distribution is reconstructed using a special-purpose reconstruction code. An 8 × 8 boiling water reactor fuel assembly has been measured at the Swedish interim storage (CLAB), using installed gamma-scanning equipment modified for the purpose of tomography. The equipment allows the mapping of the radiation field around a fuel assembly with the aid of a germanium detector fitted with a collimator with a vertical slit. Two gamma-ray energies were recorded: 662 keV (137Cs) and 1274 keV (154Eu). The intensities measured in 2520 detector positions were used as input for the tomographic reconstruction code. The results agreed very well with simulations and significantly revealed a position containing a water channel in the central part of the assembly.

A Tomographic Method for Verification of the Integrity of Spent Nuclear Fuel Assemblies - I: Simulation Studies

Abstract A tomographic method for experimental investigation of the integrity of used light water reactor fuel assemblies has been developed. It is based on spectroscopic measurements of the gamma radiation from fission products in fuel rods. The method utilizes beforehand information about the nominal geometry of both the measured fuel assembly and the measurement equipment. A reconstruction code of the algebraic type has been written. The potential of the technique has been examined in extensive simulations, assuming a gamma-ray energy of either 662 keV (137Cs) or 1274 keV (154Eu). The ability of detecting various configurations of manipulated rods, both single and in groups, has been investigated. Two main types of manipulations have been simulated. First, there is the removal of rods without replacement. The results indicate that all investigated configurations of removed rods in boiling water reactor (BWR) fuel can be reliably detected using 137Cs radiation. For pressurized water reactor (PWR) fuel, the same result is obtained, with the exception of the most central positions. Here, the more penetrating radiation from 154Eu may have to be used. Second, there is the replacement of rods with fresh fuel or fuel-like material. The results clearly indicate that all simulated cases of such manipulation can be most confidently detected. The simulations include various configurations of replaced rods in both BWR and PWR fuel, using both gamma-ray energies.

Gamma-Ray Spectroscopy Measurements of Decay Heat in Spent Nuclear Fuel

Abstract A method for determining the residual thermal power in spent nuclear fuel using gamma-ray spectroscopy is suggested. It is based on the correlation between the residual power and the 137Cs activity, which is nearly linear for fuel with cooling times between 10 and 50 yr. Using available data of calorimetrically measured values of the decay heat in 69 boiling water reactor and pressurized water reactor spent-fuel assemblies resulted in agreement with a standard deviation of 3%.

A tomographic method for experimental verification of the integrity of spent nuclear fuel

A tomographic method for verification of the integrity of spent nuclear fuel assemblies has been developed. The gamma radiation field emanating from emitted radiation from within the assembly is recorded and utilised for reconstructing the internal source distribution. Simulations of an experimental procedure have indicated the ability of detecting the absence of fuel rods with high confidence. The method has been verified experimentally, both for a fuel model in laboratory environment and for spent fuel in a fuel handling pool.