Evaluation of a gas chromatographic method for detection of irradiation of chicken and a chicken meat product

A method was developed for the detection of irradiation of chicken and chicken meat products. The method consists of the extraction of fat from chicken skin or a chicken meat product, separation of hydrocarbons with an alumina column and gas chromatography (GC) and GC-mass spectrometry analyses of the hydrocarbons 16:2, 16:3, 17:1 and 17:2 formed from oleic, linoleic and stearic acids during irradiation. These hydrocarbons were only detected in irradiated samples at doses of 5 and 10 kGy. The mean concentrations of the hydrocarbons were linearly related to the dose levels of irradiation in the case of chicken fat. The concentrations of two of the hydrocarbons (16:2 and 17:1) gave the best correlation with dose. When a dose of 10 kGy was used, the concentrations of major degradation products were 1.5-5.0 mg/kg fat. The same relationship was not found in the case of chicken meat products because the amounts of hydrocarbons detected after irradiation with the same doses were similar. On the basis of this study it was clearly demonstrated that it is possible to judge analytically whether or not a chicken sample or a chicken meat product has been irradiated at doses of 5 or 10 kGy. It should also be possible to recognise samples irradiated with doses below 5 kGy.     

The effect of lateral flooding on the coolability of irregular core debris beds

The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration.     

Isolation of the liver N-aspartyl-beta-glucosaminidase in aspartylglucosaminuria

The isolation of liver N-aspartyl-beta-glucosaminidase in human aspartylglucosaminuria, where this enzyme activity is diminished, yields an enzyme molecule with the same molecular weight and pH optimum as the normal enzyme. Its activity is 10% of that of the control preparation. Combination of both enzymes results in the summation of both activities, and the pathological enzyme does not inhibit the control preparation. It is concluded that no change into a totally different isoenzyme has occurred in aspartylglucosaminuria.