Experiments of flue gas treatment by electron beam were carried out, using simulated ligniteburning flue gas containing SO2 (5500 ppm), NO (390 ppm) and H2O (22%) . Removal efficiency of SO2was more than 90% at a dose of 1-2 kGy. It shows applicability of electron beam for treatment of lignite-burning flue gas. Another removal reaction besides the radiation-induced radical reaction and the thermal reaction occurring without irradiation was suggested by the facts that removal of SO2by the radical reaction is only a few hundreds of ppm and the removal amounts by thermal reaction under irradiation is lower than a half of total desulfurization. The mechanism similar to thermal reaction was proposed, assuming simultaneous uptake reaction of SO2and NH3on the surface of liquid aerosol It was suggested that ammonium nitrate having deliquescence relative humidity (DRH) of 60% at 25°C plays an important role in producing liquid aerosols. Decrease of DRH of ammonium nitrate with elevating temperature and with formation of double salt of ammonium sulfate results in enhancement of formation of liquid aerosols.
Recently, 131I has become to be used for treatment by the increment of its dose. Treatment doses for thyroid cancer amount to GBq order. The regulations with regard to the discharge of the waste drainage containing131I are very strict, and it burdens the drainage treatment facilities. When usage of131I for treatment becomes popular, the drainage treatment facilities may groan under the heavy burden. We made an equipment with activated carbon impregnated with per-bromine ion which efficiently adsorbs131I in drainage by halogen substitution reaction and tested it at the drainage facility in a hospital. The removal efficiency of131I was more than 99% using only a single impregnated carbon column (diameter 100 mm, length 220 mm) under 4 L/min flow rate. For a practical application, it will be important to improve the performance and the ability for a long term use.
The spreading use of organic insulating materials in environments such as space and nuclear power stations increases the concern about the reliability of electrical insulation in these environments due to radiation and magnetic field effects on the surface breakdown of polymers. The experiment was carried out by DC impulse voltage under 495 mT.Polyphenylene oxide, which was irradiated in air up to 100 kGy and 1 MGy with dose rate of 10 kGy/h using a60Co gamma-source, has been used as the test sample. The total dose of gamma-ray irradiation effects on the discharge quantity have been studied The changes of discharge quantity are discussed with applied magnetic field under 495 mT and the frequency of applied impulse voltage in the range from 100 Hz to 150 Hz. The discharge quantity increased with increasing the total dose of gamma-ray irradiation, and decreased with applied magnetic filed. The discharge quantity increased with increasing the frequency of applied impulse voltage.