No abstract available

[en] This report describes the method employed in the preparation of alumina supported iridium catalysts, with metal contents between 30 and 40%, that will be used for hydrazine monopropellant decomposition. (author)

[en] Second-order rate constants for aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (1a-h) have been measured spectrophotometrically in 80 mol % H₂O/20 mol % DMSO at 25.0 .deg. C. The Bronsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (1d) with a series of primary amines curves downward, which has been taken as evidence for a stepwise mechanism with a change in rate-determining step (RDS). The Hammett plots for the reactions of 1a-h with hydrazine and glycylglycine are nonlinear while the Yukawa-Tsuno plots exhibit excellent linearity with ρ_X = 1.22-1.35 and r = 0.57-0.59, indicating that the nonlinear Hammett plots are not due to a change in RDS but are caused by stabilization of substrates possessing an electron-donating group (EDG) through resonance interactions between the EDG and C=O bond of the substrates. The α-effect exhibited by hydrazine increases as the substituent X changes from a strong EDG to a strong electron-withdrawing group (EWG). It has been concluded that destabilization of hydrazine through the electronic repulsion between the adjacent nonbonding electrons is not solely responsible for the substituent dependent α-effect but stabilization of the transition state is also a plausible origin of the α-effect

[en] The data published over the past 15 years on the search for newer anticonvulsant drugs are generalized. Pyrrolidinedione, quinazolinone, xanthone, hydrazine and thiadiazole derivatives manifesting anticonvulsant activity in model in vivo tests in rodents are considered.

[en] A simple and rapid method for the determination of total uranium in electrolyser samples is described. NaNO_2 is used as an oxidizing agent for complete conversion of Uranous to Uranyl and also for destruction of hydrazine present in the sample. The molar absorption coefficient of uranyl ion was found to be 8 liter/mole-cm. The correlation coefficient was found to be 0.999. The relative standard deviation for the estimation of uranium was found to be well within limits required for process control analysis. (author)

[en] Reduction kinetics of Pu(IV) by N,N-dimethylhydrazine (NNDMH) were studied by spectrophotometry, and the reduction rate equation in 3M (mol/dm³) nitric acid was obtained. The reduction properties of NNDMH for U(VI), Np(VI), and Pu(IV) was studied in the mixture solution of trin- butylphosphate diluted to 30 vol.% by n-dodecane (30% TBP) and 3M nitric acid. It was confirmed that NNDMH selectively reduce Np(VI) to Np(V) without affecting the valences of U(VI) and Pu(IV) in a few minutes. Numerical simulation indicated that 99.9% of Np was separated from U and Pu applying NNDMH for a mixer-settler. (author)

[en] N,N-dimethylhydroxylamine (DMHA) is an effective novel salt-free reductant used in spent fuel reprocessing. This paper reports the effect of monomethylhydrazine (MMH) on γ-ray radiolysis and radiolytic by-products of DMHA in HNO₃. The presence of MMH improves the stability of DMHA against radiation significantly, the main radiolytic by-products are N-methylhydroxylamine, HCHO, HCOOH and HNO₂, which concentration increases with the dose. The concentration of N-methylhydroxylamine increases with the MMH concentration, but that of HCHO, HCOOH and HNO₂ decreases with increasing MMH concentration. These results will provide considerable reference for the application of DMHA in the PUREX process. (author)

[en] Chemical decontamination agent is used in an acidic solution and the main chemicals are hydrazine and cuprous ion. From the dissolution tests on magnetite particles and oxide layer formed on Type 304 SS contaminated with radionuclides, it was found that the decontamination agent successfully dissolved the oxides. Furthermore, the decontamination agent shows good corrosion compatibility. As the decontamination is operated in a high radiation field, it is essential to evaluate the radiation stability of the developed chemical decontamination agent. The objectives of the study are to evaluate the radiation stability of hydrazine and to elucidate the decomposition reaction of hydrazine. Especially, the reaction mechanism for producing the ammonium ion from the decomposition of hydrazine is suggested. Radiation stability of the decontamination agents developed in foreign countries is also compared with that of the developed chemical decontamination agent. In this study, we obtained that there is no decomposition of hydrazine by radiolysis below 1 kGy. In addition, we confirmed that the radiolysis of hydrazine and production of ammonium ion are affected by the copper ion in the chemical decontamination agents. These findings are supportive to the decomposition stability of hydrazine in a high radiation field and inferred to attribute the higher stability of HYBRID decontamination solution

[en] PNC has been promoting actinides partitioning studies as a part of advanced reprocessing system development efforts since 1990. Concurrently, the general TRUEX process was studied as a reference partitioning tool. In the counter-current flow-sheet tests using mixer-settler, some portion of U,Pu and Ru used to remain in the solvent by conventional stripping methods. Therefore a new 'Salt-free' solvent-washing methods were studied to remove these nuclides and Zr from TRUEX solvent. Hydrazine oxalate was tested for U. Hydrazine oxalate, hydrazine carbonate and TMAH (tetramethylammonium hydroxide) were tested for Ru and Zr. The stripping behavior of Pu by hydrazine oxalate was studied through the counter-current test. It was concluded that various 'Salt-free' reagents will be effective, if these are used in combination manner, for reducing- these nuclides retention in the solvent. (authors)

[en] Hydrazine is one of the most excellent oxygen scavengers used in the secondary circuit of nuclear power plants. Furthermore, in some pants, the hydrazine is used as a source of hydrogen required to suppress radiolysis of the coolant water in the primary loop. When hydrazine was exposed in the high temperature and high pressure water, it can be decomposed into the various products such as NH₃, N₂, H₂, and NO₃ ions. As the result, the pH of solution containing hydrazine in the condition of the high temperature and high pressure can be changed by those decomposed products. In the present work, we investigated the decomposition behavior of hydrazine in ETA (ethanol amine) solution. In addition, we measured the high temperature pH at 553 K on the various hydrazine/ETA solutions for confirming the applicability of the yttria stabilized zirconia (YSZ)- based pH electrode in secondary circuit of the nuclear power plants