Radiochemical Separation And Half-life Measurement Of ～(132)I

132I is a short-lived fission product nuclide. Its decay data are critical nuclear parameter.However,uncertainty of measured data is big not to meet the need.So it's very significant to remeasure accurately the decay data of 132I. In order to prepare radiochemical pure 132I to measure precisely its decay data, radiochemistry separation was studied and a reasonable procedure of separating 132I was established. Moreover its half-life was remeasured .It's impossible to obtain radiochemical pure 132I by separating methods directly, because many Iodine isotope such as 131I,133I,135I are in fission products and the half-life of 132I is shorter than that of other Iodine isotope. It must be separated indirectly from fission products of 235U. Because the half-life of 132Te ,which is mother nuclide of 132I, is longest of Tellurium isotope in fission products, 132Te is as the source of 132I. Method of 132I separated indirectly has two steps. First its parent nuclide 132Te is separated from fission products. Then 132I is separated from 132Te. By this method the interference of other isotope nuclides of 132I is greatly decreased and even eliminated.At first a procedure of precipitation-soak was designed. It has two main steps that radiochemical pure 132Te is separated from fission products by precipitation and 132I is assumed to be separated from the sediment of 132Te by soak with appropriate solution. In the precipitation , NaHSO3 and SO2 were as reducers respectively; Na2TeO3 was as the carrier solution ; 113Sn, 124Sb, 137Cs and mixed radioactive fission products as radioactive tracer; the chemical recovery of Te in the different reducing conditions and Fe(OH)3 precipitating process were studied; furthermore, the decontamination factors of some principal nuclides such as I , Mo , Sb etc in vaporation of HBr and 132Te precipitation process were studied. The experiment results are shown as following: The reductant NaHSO3 can reduce Te(IV) to metal Te absolutely and avoid the splash of radioactive solution with SO2; Because of Te amphotere its chemical recovery is low and unstableby precipitating Fe(OH)3; I decontamination effect is good but Sn, Sb, Cs etc bad in the evaporation process of HBr; however ,the decontamination effect of I and other main nuclides is quite the contrary in other chemical procedures . In the soak , soaking recovery of 132I from the sidement of Te was studied with oxidant, reductant, acidity, alkalesance and neutrality,respectively. It's proved that radiochemical pure 132I cann't be obtained.A procedure of evaporation-extraction was designed again. It has proved that evaporation process of concentrated HBr has a good effect on obtaining 132Te without Iodine.Then 132Te is placed to attain the equilibrium(132Te-- 132I). Finally I32I is extrated with CCI4 by the method of Japanese Nagao Ikeda. By a series of experiments of the density of HNO3, KI in aqueous and I2 in CCI4, optimum factors were chosen to increase the extration recovery of I32I. Moreover experiments of decontanmination were done. The procedure of evaporation-extraction can be well used for separating I32I from fission products . It is described as follows: 5 ml of concentrated HBr were added to the sample of irradiated 235U solution in a beaker. Then evaporated nearly to dryness by a burner. 5 ml of concentrated HBr was added to dissolve and evaporated repeatly . The residue is dissolved with 0.5mol/L HNO3 and transfered to a centrifuge tube . 12i-i gKI is added and Iodine is extracted twice with equal volume CCl4 (100g I /ml) .The aqueous phase stands for more than 12 hours to attain the transient equilibrium between 132Te and its daughter 132I. Then 132I is extracted with equal volume CCl4 (l00ug I /ml). The organic prase is washed twice with equal volume 0.5moI/L HNO3. 132I is back-extracted with equal volume saturated SO2 solution.Using above procedure, The chemical recovery of 132I is about 60%. The decontamination factors of Te, Ba, La etc. are more than 104 and those of Ce, Zr, Rh etc. are more than 103. The whole pro...