Post accident investigation

Sulphuric acid at 93% was added to p-nitrotoluene. The temperature reached 160°C due to a failure of the thermal control system. The sulphonic acid formed decomposed violently at this temperature. The post-accident investigation showed that the decomposition started between 160 and 190 C. In fourteen minutes the temperature rose to 190-224°C and in one minute and thirty seconds to 224-270°C. A large volume of gas was then released during the eruption. The phenomena caused by the decomposition of nitrated derivatives in the presence of sulphuric acid will be addressed several times. What these incidents have in common is the formation of large carbonised volumes. This phenomenon is common with sulphonic acids. The nitro group role is to destabilise intermediate compounds and final compounds and to generate... 

Furfural was added drop by drop to a solution of 10% of hypochlorite at 20-25 C. At the end of this operation a violent detonation destroyed the equipment. The post-accident investigation showed that during the handling, pH decreases slowly down to 8.5, then suddenly to pH 2. At the same time the temperature rises suddenly to 70°C. The study showed that the same is true for benzaldehyde. 

A post-accident investigation discovered that the indicator light circuit was wired to indicate presence of power at the valve, but it did not indicate valve position. Thus, the indicator showed only that the activation button had been pushed, not that the... 

Other accompan5ung causes have been indicated by the post-accident investigations. These have... 

Weak points specified at supervision level are related in principle to failures to correct known problems, inadequate supervision or intended violations, which are very difficult to detect and identify as an accident cause during post accident investigation. 

TTie results of the laboratory studies mentioned above have been clearly supported by the TMI-2 post-accident investigations (Vinjamuri et al., 1984 a), which will be discussed in more detail in Section 7.4.2. 

The data obtained in the measurements showed that about 1% of the iodine inventory of the central fuel module reached the blowdown suppression tank, while only 0.23% of the cesium inventory appeared there. These data and those taken from the simulated broken line indicated that cesium deposited in this line more readily than iodine the reverse situation occurred in the upper plenum of the reactor pressure vessel. Here, almost no cesium was detected on the deposition coupons while iodine was present in amounts similar to those in the line of the low-pressure injection system. Besides iodine, silver was found on the upper plenum coupons in equivalent amoimts in addition, the iodine deposited on these coupons could not be leached by water, indicating that it was present there as an insoluble compound. From these data it was concluded that fission product iodine was transported out of the reactor core as Agl, rather than as Csl. Formation of Agl as the main iodine compound deposited in the upper plenum of the reactor pressure vessel is a behavior markedly different from that observed in other in-pile experiments and in the TMI-2 post-accident investigations. The reason for this behavior was assumed to be the low concentrations of both cesium and iodine present in the low-bumup fuel, which resulted in a very high stoichiometric excess... 

After the incident has been declared under control and acute emergency conditions no longer exist, post-incident activity and stabilization should commence. Activity during this period may include cleanup and disposal, accident investigation/incident reconstruction, site restoration, and emergency plan evaluation. 

These field offices have no relation of interest with the mine operators, or with the state and county government. The federal safety supervisions must exchange their posts in rotation every two years. If a coalmine accident involves three or more deaths, the local safety supervisors are disqualified from participating in the accident investigation. Instead, the federal office will dispatch safety supervisors in other regions to do so. These measures ensure objective and impartial supervision and accident investigation. 

With regard to ensuring employee safety and health, all of OSHA s subparts listed in Figure 9.1 could be employed by employers not only to protect workers but also to ensure OSHA compliance. In this section, we specifically list and describe those standards that are most often cited in Industry Group 138 for lack of compliance or willful violation of Occupational Safety and Health Standards (29 CFR 1910) found during OSHA audits and determined to be causal factors during post-accident/fatality investigations. 

Because accidents must be reported to supervisors immediately, all laboratories must post a list of emergency telephone numbers. Although generic accident report forms are available (Fig. 19.2), it is recommended that the winery develop its own forms to document accidents as well as those used by supervisors conducting accident investigations. Required information includes names and telephone numbers of the injured and witnesses, the date, time, and location of the incident, a description of the incident, the involved department(s), and the contract person and telephone number. 

Whilst this chapter will not answer all of these questions, it proposes that investigative tools can be used both pre-incident to answer the why and post-accident to answer the how . 

The first step in developing an accident investigation system is to set up a system that allows employees to report accidents (without retribution). If employees fear for their jobs, not only will they not report accidents, they will also hide information that could possibly prevent accidents. And of course companies are obligated by law to post any reportable injury. A reportable injury is an occupational death, injury, or illness that must be recorded on OSHA Form 200, Log of Occupational Injuries and Illnesses. Other countries have comparable reporting systems. 

Accidental pollution. This category includes industrial accidents, some of which are described below. Post-disaster investigations often show that the accidents were preventable. In many cases, an entire industry learns from the accident and implements safeguards to prevent a recurrence. 

Corrective efforts frequently directed at incidents involve a series of firefighting operations, whereas what is needed is in-depth direct action to prevent recurrence. Furthermore, there has been too much emphasis on post-accident strategies, such as accident investigation, and too little on preaccident strategies, such as control of the working environment. 

Agencies would be horrified, we imagine, if investigators recorded their second-hand conclusions and impressions before they collected physical evidence from the accident site. But agencies have institutionalized the rhetorical transformation of experience in the post-accident interview. Agencies use the methods of science to help them collect physical evidence at the site. 

The post-processing In the post-processing, influencing factors mainly include dealing with the aftermath, investigation, and the accident evaluation summarizing. 

It was notoriously difficult, however, to link HSE culture to major accident risks and process safety in any clearly communicated manner. In the fall of 2004, a serious gas blowout occurred on Statoil s Snorre Alpha platform. A catastrophic outcome was avoided only by chance, and by a hazardous rescue operation by the remaining crew. Poor HSE culture appeared as an important contributing factor in several post-event accounts, including a thorough investigation report commissioned by Statoil, as well... 

Besides the post-TMl plant improvement programmes (prevention) which cost millions of dollars for each plant, in the Western countries investigations were started on what else could reasonably be done to the plants with the goal of stopping the progression of an impending severe accident or to mitigate its consequences. 

Although relevant exercises have been conducted, and Cold War nuclear weapons programs provide validated analytic platforms, there have been no actual post-det terrorist incidents involving an IND or RDD to date. Consequently, no technical investigations in the contemporary embodiment of nuclear forensic analysis exist for an actual post-det situation, and all discussed case studies necessarily focus on interdicted, pre-det materials. (However, a nuclear accident that is perhaps exemplary of maximum-credible consequences of successful terrorist activities was the uncontrolled criticality and resultant explosion of the Soviet RBMK power reactor at Chernobyl in 1986.)... 

---