Accidents During Chemical Reactions

There are numerous accidents that have occurred during a chemical reaction or process 81. Three instructive examples will be described in the following sections. 

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This compound is perfectly stable. In addition to the accident described on p.187, which happened during electrolysis and was caused by chlorine, there was another accident, which is not really linked to a chemical reaction. 

National Transportation Safety Board (NTSB), 2000. Hazardous Materials Accident Brief Whitehall, Michigan, Chemical Reaction During Cargo Transfer, June 4, 1999. 

The accident during the chemical process described below is an example of a runaway reaction producing a toxic substance which results in environmental pollution 101. ... 

Figure 4 shows the experimental results of the simulation test on the loss of chemical reaction accident tliat is the severest accident for the temperature fluctuation of the secondary helium gas. The supply of the raw gas for the hydrogen production, methane, was suspended during the normal operation to simulate an accident at the hydrogen production system. The SG inlet heliiun gas temperature increased 228°C due to the loss of chemical reaction, however, helium gas temperature at SG outlet showed almost stable value. The fluctuation range of the helium gas temperature was from -5.5°C to +5.0°C at SG outlet, which is within the target range of HTTR-H2. 

Chemical processing and mixing under controlled circumstances safely creates many of the useful products we have come to depend on in our daily lives. However, when certain chemicals come in contact with each other during uncontrolled situations, such as accidents and spills, dangerous reactions can occur. This chapter will focus on incompatible chemicals, safe storage practices, water- and air-reactive materials, and some of the hazards to responders that may occur as a result of an uncontrolled chemical reaction. 

During an accident, many of the ambient conditions inside the reactor plant which are of relevance for fission product chemical reactions (such as temperatures, concentrations, redox properties, reaction partners) are fundamentally different from those prevailing during normal operation periods. As a consequence of these changed conditions (which, in addition, may be different for different accident scenarios), a specific behavior of the fission products will result. In order to evalu-... 

With the sole exception of the noble gases, during reactor normal operation as well as in the course of reactor accidents, all the fission products are subjected to chemical reactions which govern their transport and behavior. These reactions have to be taken into account, therefore, when the release of fission products in anticipated accidents is calculated. However, chemical reactions and physical phenomena to be expected under the conditions of reactor accidents, as well as the resulting products, are only accessible for theoretical calculations in a very global manner. For this reason, experiments are needed at least to validate the theoretical results or, in many cases, to get an idea on the possible reaction mechanisms. The planning and performance of such experiments and the interpretation of the results obtained will pose some problems which have to be taken into consideration before the work is begun. 

When two reagent chemical substances are put together in a test tube, the chemical reaction is almost immediate. The simation is somewhat different when a corrosive contacts a biological tissue. During skin accidents, we know that it takes some seconds for the first lesions to appear. After a short period, kinetics of diffusion will set up in a variable way according to the nature of the corrosive. 

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