Incident Consequences

The acronym for chemical process quantitative risk analysis. It is the process of hazard identification followed by numerical evaluation of incident consequences and frequencies, and their combination into an overall measure of risk when applied to the chemical process industry. It is particularly applied to episodic events. It differs from, but is related to, a probabilistic risk analysis (PRA), a quantitative tool used in the nuclear industry... 

The development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques for combining estimates of incident consequences and frequencies... 

In the first approach, a vapor cloud s potential explosive power is proportionally related to the total quantity of fuel present in the cloud, whether or not it is within flammable limits. This approach is the basis of conventional TNT-equivalency methods, in which the explosive power of a vapor cloud is expressed as an energetically equivalent charge of TNT located in the cloud s center. The value of the proportionality factor, that is, TNT equivalency, is deduced from damage patterns observed in a large number of vapor cloud explosion incidents. Consequently, vapor cloud explosion-blast hazard assessment on the basis of TNT equivalency may have limited utility. 

This typically considers injuries to personnel and damage to plant and equipment. In a few more highly developed systems, information on potential consequences is also collected. Normally the severity of the incident consequences (or in some cases its potential consequences) will determine the resources that are put into its investigation. 

The Limerick analysis accounted for a revised list of incident Initiators based on the Limerick plant design and a more detailed analytical modeling of event sequences following each incident initiator. Plant-design-specific and site-specific data were also included in the analysis of the Limerick Mark II containment and in the meterology and demography imput to the evaluation of incident consequences. 

Chemical Process Quantitative Risk Analysis(CPQRA) The numerical evaluation of both incident consequences and probabilities or frequencies and their combination into an overall measure of risk. 

Some of the key factors to consider when designing, operating and maintaining intentional chemistry processes are listed below. These factors can have a major effect on either the likelihood of a chemical reactivity incident or the severity of the incident consequences. 

These activities may introduce many hazards, such as contaminants, materials of repair corrodible, combustible or catalytic in the given environment, blocked vents, open valves etc. into the restarted plant, while shutdown and startup are, in any event, the most dangerous periods. Many examples of reactive hazards thus introduced are to be found in [1], Mutatis mutandis, this is also true of the laboratory this Handbook contains many incidents consequent upon stopping a reaction and/or its agitation to sample, change cooling bath, etc. 

Risk is defined as a measure of economic loss, human harm, or environmental harm in terms of both the incident likelihood and the magnitude of the loss or injury. Thus, any effort to reduce the risk arising from the operation of a processing facility can be directed toward reducing the likelihood of incidents (incident frequency), reducing the magnitude of the loss or injury should an incident occur (incident consequences), or some combination of the two. 

Quantitative Risk Analysis (QRA) models the events, incidents, consequences, and risks, and produces numerical estimates of some or all of the frequencies, probabilities, consequences, or risks.38 55 QRA can be done at a preliminary level or a detailed level, and in all cases may or may not quantify all events, incidents, consequences, or risks.56 QRA is the art and science of developing and understanding numerical estimates of the risk associated with a facility or an operation. It uses highly sophisticated but approximate tools for acquiring risk understanding. 

Safeguard a precautionary measure or stipulation. Usually equipment and/or procedures designed to interfere with incident propagation and/or prevent or reduce incident consequences... 

The achievement of proper operating conditions, prevention of incidents, or mitigation of incident consequences, resulting in protection of workers, the public, and the environment from nndne radiation hazards. This covers nuclear power plants as well as all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nnclear materials for medical, power, industry, and military uses. In addition, there are safety issues involved in products created with radioactive materials. The Office of Nuclear and Facility Safety establishes and maintains the Department of Energy (DOE) reqnirements for nuclear criticality safety. The DOE s detailed requirements for criticality safety are contained in Section 4.3 of the DOE Order 420.1, Facility Safety. Criticality safety requirements are based on the documented safety analysis leqnired by 10 CFR 830, Subpart B. 

Another line of demarcation separates whether an IND or RDD was successfiilly exploded (a post-detonation scenario), or whether the device was interdicted or failed to fire (predetonation situation). This differentiation reflects very different incident consequences, as well as the ensuing NFA. 

Here, hazard identification is critical, because a single event may be benign, but cumulative or combinational effects may lead to a major incident. Consequence analysis reveals the effect of various incident outcomes. The likelihood of initiating incidents is estimated in likelihood analysis. Then, it is a question of risk interest, so it is necessary to categorize the risks as discussed in the previous clause, because one may be interested in finding human fatalities or injuries while others may be interested in loss of assets. 

Risk analysis The development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques for combining estimates of incident consequences and frequencies (e.g., an ammonia cloud from a 10 Ib/s leak might extend 2000 ft downwind and injure 50 people. For this example, using the data presented above for likelihood, the frequency of injuring 50 people is given aslxlff x0.1x0.1 = lx 10" events per year)... 

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