[en] If a Loss-of-Coolant-Accident (LOCA) inside the reactor building were to occur, it could generate debris. Debris that could accumulate on the sump screens would increase head loss across the resulting debris bed and sump screen. Furthermore, materials within containment could dissolve or corrode, and result in precipitation or corrosion products which could add to the debris load and further increase head loss across the debris bed and sump screen. This head loss might be sufficiently large such that it might exceed the net positive suction head (NPSH) margin of the RIS and EAS pumps, which would challenge the safety function of RIS and EAS system.This paper describes the impact of chemical effect on sump strainer head loss in a power plant in China. The test fluid used representative plant coolant chemistry, and the test fluid temperature was controlled to simulate the post-LOCA plant coolant temperature profile. Water samples were taken periodically during the test and then analyzed for elemental concentrations of the Al, Si, Na, Ca. Following the tests, we can conclude that no visible precipitation was noted during the test. The aluminium coupon was corroded, but did not form precipitation in the solutions during the test. The available Ca ions in TSP environment were potentially related to the Ca_3(PO_4)_2 precipitation. Overall, Ca ICP levels were reducing over time which may indicate that the Ca was used to form precipitate. Although the chemical reaction occurred and precipitation formed during the test, it didn't have remarkable impact on the sump strainer head loss. (author)

[en] The fresh keeping period of strawberry irradiated with 4.0 kGy dose and stored at room temperature was prolonged to 6 days. Further experiment showed that the irradiation treatment decreased the number of mold in strawberry by two orders of magnitude, inhibited the strawberry fruit respiration and water loss, therefore, improved the effect of strawberry fresh-keeping

[en] Austenitic steel is a candidate material for Supercritical Water-Cooled Reactor. This study is to investigate stress corrosion cracking behavior of HR3C under effect of supercritical water chemistry. A transition phenomenon of water parameters was monitored during a pseudo critical region by water quality experiments at 650degC and 30 MPa. The stress-strain curves and fracture time of HR3C were obtained by slow strain rate tensile tests in supercritical water at 620degC and 25 MPa. The concentration of dissolved oxygen was 200-1000 μg/kg and the strain rate was 7.5 × 10"-"7/s. Recent results showed the failure mode was dominated by intergranular brittle fracture. The relations of oxygen concentration and fracture time were nonlinear. 200-500 μg/kg of oxygen accelerated the cracking but a longer fracture time was measured when oxygen concentration was increased to 1000 μg/kg. Chromium depletion occurred in the oxide layer at the tip of cracks. Grain size increased and chain precipitated phases was observed in the fractured specimens. These characteristics were considered to be contributive to the intergranular stress corrosion cracking. (author)

[en] In this experiment, the factors affects the pigment change of irradiated garlic including temperature, irradiation dosage, native species and color developing reagent were studied and the mechanism of pigment change was discussed

[en] An intelligent radiation dosimeter, with such functions as signal collection and data processing, store, print and display, has been developed. Its detector is made of a micro-semiconductor. This dosimeter can be used in laboratories for agricultural ⁶⁰Co irradiators, radiotherapeutic facilities and other small and medium-size ⁶⁰Co irradiators

[en] A p-n junction semiconductor may be used as a radiation detector. Such a study is reported here. Its dosimetry specificities, include dose, dose rate, precision, stability, depth dose distribution and directional response, were studied in a ⁶⁰Co field. It is shown that the detector performs well. It exhibited a precision of ±0.05% (std dev.) and a stability of ±0.16% (std dev.), respectively. (author)

[en] Low dosage irradiation could inhibit the proliferation and buds germination of Chinese chestnut. Preservation rate could be increased to 91.1% by irradiation after storing at 2-4 degree C for 45 days and reached to 92.0% for 60 days when treated with both validamycin A and irradiation

[en] The high temperature electrochemical corrosion behavior of zirconium alloy was studied by potential dynamic polarization and electrochemical impedance spectrogram (EIS) under three normal boron-lithium water chemistry conditions with the same pH and the uniform corrosion behavior of zirconium alloy was investigated by weight gain and microanalysis under two lithium-concentrated water chemistry conditions. The high temperature electrochemical corrosion tests indicate that the increase of boron concentration can reduce the passive current density and increase the electrochemical impedance value of zirconium alloy under three normal boron-lithium water chemistry conditions despite of the same pH, consequently the boron is beneficial to corrosion inhibition of zirconium alloy. The uniform corrosion tests show that adding boron can obviously decrease the corrosion weight gain, oxide film thickness and compact the oxide films by contrast to the lithium-concentrated water chemistry condition without boron, thus the boron is beneficial to improve the corrosion resistance of zirconium alloy under lithium concentrated water chemistry conditions. (authors)

[en] Under the loss of coolant accident in nuclear power plants, the blockage of sump strainers may be resulted from chemical effects, which will affect the recirculation function of the emergency core cooling system or the containment spray system, disabling the cooling of the core and containment, and threatening the safety of nuclear power plants. Study on the effects of potential chemical products on sump strainer head loss after the loss of coolant accident in Qinshan Phase II Extension Project was conducted. The results showed that the alumina-bearing material and the insulation material released aluminum and silicon in the sump environment, and that aluminum and silicon formed chemical precipitation and deposited on the debris bed. This can result in the blockage of the debris bed and the reduction of the porosity, and increase the head loss of the sump strainer. There are chemical effects after loss of coolant accident in Qinshan Phase II Extension Project, and it should be considered in the sump strainer performance evaluation and downstream effect analysis. (authors)

[en] Austenitic stainless steels have been widely used as the major structural materials due to excellent combination of mechanical properties and corrosion resistance in high temperature. 310 SS has been regarded as a most promising material of fuel cladding for SCWR. It is well known that SCC of austenitic stainless steels is influenced by water chemistry, such as oxygen. In order to obtain a deep understanding of the SCC behavior of 310 SS in SCW, more research is urgently needed. The effects of dissolved oxygen content on the tensile properties and stress corrosion cracking (SCC) susceptibility of austenitic stainless steel 310 SS were studied by performing Slow Strain Rate Tensile (SSRT) tests. The SSRT tests were carried out in supercritical water at temperature of 620℃, a pressure of 25MPa, and a strain rate of 7.5×10- 7 s-1. The dissolved oxygen content was included 0, 500, 1000, 2000, and 8000 ppb. The SSRT tests were performed in a supercritical environment corrosion testing machine system, which can control the DO concentration, pH and conductivity. After the tests, strain–stress curves were analyzed to identify the mechanical properties of 310 SS. The morphologies of the side surface and fracture surface on the specimens were conducted by scanning electron microscope (SEM), and the chemical composition and structure of the oxide formed were examined by energy dispersive spectroscopy (EDS), in order to investigate fracture mode and to evaluate SCC susceptibility. The results show that the elongation decreased dramatically with the increasing of dissolved oxygen concentration. Cracks on 310 SS were widely distributed over the whole gauge section and a brittle fracture mode was observed on the fracture surface. The Cr content the oxide layer on the surface showed significant increase with the increasing of DO concentration. The corrosion products formed on 310 SS were Fe/Cr oxide layers, and they are classified into two layers, an outer Fe-rich oxide layer and an inner Cr-rich oxide layer.