Thermal decomposition hazard evaluation of hydroxylamine nitrate.

Hydroxylamine nitrate (HAN) is a reductant used in nuclear material processing and as a component in liquid propellants. Its instability and autocatalytic decomposition have led to safety concerns. Prior research has shown HAN's role in chemical reactions but has not fully resolved its thermal decomposition risks. No prior work had resolved the energy release potential of HAN under various conditions. This gap motivated the need for calorimetric and computational studies. The nuclear industry requires safe handling protocols for HAN. Existing data on HAN decomposition is limited to low concentrations. This paper addresses the lack of detailed thermal hazard information for 24 mass% HAN/water.

This study aims to evaluate the thermal decomposition hazards of 24 mass% HAN/water. The researchers focused on assessing the energy release potential and safe handling conditions. They wanted to understand the decomposition behavior under different thermal scenarios. The motivation was to prevent incidents caused by HAN's instability. The study also aimed to calculate the gas phase enthalpy of formation of HAN. They used both semi-empirical and high-level quantum chemical methods. The goal was to provide data for safe storage and handling of HAN. This work supports the nuclear and chemical industries in managing HAN-related risks.

The researchers used calorimetric measurements to study the thermal decomposition of 24 mass% HAN/water. They applied MOPAC for semi-empirical calculations of the gas phase enthalpy of formation. Gaussian 03 was used for high-level quantum chemical methods. CHETAH was employed to estimate the energy release potential of HAN. The Reactive System Screening Tool (RSST) was used to assess decomposition hazards. An Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) was also used. These tools helped determine safe handling and storage conditions. The methods combined computational and experimental approaches to evaluate HAN's thermal behavior.

The study found that 24 mass% HAN/water undergoes thermal decomposition with significant energy release. The gas phase enthalpy of formation was calculated using MOPAC and Gaussian 03. CHETAH estimated the energy release potential, showing HAN's instability. RSST results indicated the onset temperature for decomposition. APTAC provided data on pressure and temperature changes during decomposition. The results suggest that HAN can reach high temperatures under uncontrolled conditions. The study identified safe handling and storage conditions for HAN. These findings help prevent incidents related to HAN's autocatalytic behavior.

The authors concluded that 24 mass% HAN/water has a high thermal decomposition hazard. The energy release potential was confirmed using CHETAH and calorimetric tools. Safe handling and storage conditions were identified based on the study's findings. The gas phase enthalpy of formation was calculated using computational methods. The study supports the nuclear and chemical industries in managing HAN risks. The results suggest that uncontrolled decomposition can lead to dangerous conditions. The researchers propose that thermal monitoring is essential for HAN storage. These conclusions are based on the data from the calorimetric and computational analyses.