Accident criteria

Development of On-Site Accident Criteria for Waste Transfer Casks U.S. Department of Energy, 1989, DE89 010201 (NTIS). 

Any CMV fires that meet the accident criteria in 49 CFR 390.5 — that is, fires that occur in a commercial motor vehicle in transport on a roadway customarily open to the pubhc which result in a fatality, bodily injury requiring immediate medical attention away fi-om the scene of the accident, or disabling... 

It is thus shown that great care should be taken when following these two approaches. Personally, the author has found it far simpler and more efficient to consistently keep a clear distinction between airworthiness/failure criteria and accident criteria (as... 

Local and remote safe shutdown systems shall be sufficient to ensure that no single failure (as defined in 10 CFR 50, Appendix A, "Definitions") could result in the loss of the ability of either of these systems to achieve and maintain safe shutdown. Shutdown systems installed to ensure postfire shutdown capability need not be designed to meet the single failure criteria or other design basis accident criteria, except where required for reasons other than fire i.e., because of adverse systems interactions or spurious controls operations from fire or fire suppression system actuations). Safe shutdown systems shall be periodically tested to ensure operability. 

Acceptance criterion for the risk of accidents Criterion used to express an accepted level of risk in an activity. 

As mentioned earlier, Hakkinen (1958) employed various psychological tests for discriminating levels of accident proneness. He succeeded in establishing a very stable accident criterion due to the homogeneity in road hazards. The accident records of these subjects provided a retest reliability with split half correlations of the first four years/second four years and odd/even years (in brackets) bus drivers r = 0.58 (0.68) tram drivers r = 0.67 (0.73). 

The factor analysis revealed that the tests covered six major areas attention. involuntary control of motor functions, stability of behavior, co-ordination, reaction time, and intelligence. The factor with the highest loading on the accident criterion was the attention factor, followed by involuntary control of motor functions, stability and adaptability of behavior. Negative aspects associated with the accidents were insecurity, tension, and neuroticism. 

Evaluate Effectiveness on the Basis of Outputs and Acceptance Once the system has been implemented on its chosen site, its effectiveness needs to be evaluated at frequent intervals so that corrective action can be taken in the event of problems. The first criterion for success is that the system must generate unique insights into the causes of errors and accidents, which would not otherwise have been apparent. Second, the system must demonstrate a capability to specify remedial strategies that, in the long term, lead to enhanced safety, environmental impact and plant losses. Finally, the system must be owned by the workforce to the extent that its value is accepted and it demonstrates its capability to be self-sustaining. 

The CgHs-N Cl- (benzenediazonium chloride) enthalpy of decomposition was calculated. Comparing its value (AH j = -1.5 kJ/g) with the CHETAH criterion C, makes it moderately stable. Accidents have been observed during reactions that are schematised below and these illustrate what has been stated. They are all due to the explosive character of the diazonium sulphides formed. Here is one example ... 

The enthalpy of decomposition of this peracid is relatively high (AHcj = -1.83 kJ/g - average risk according to CHETAH criterion C,). Its aqueous solutions are unstable. Solutions that contain 80% of peracid detonate when they are stirred (even at -10°C). The usual way of preparing this peracid involves the effect of hydrogen peroxide when metaboric acid is present however, although this operating method was followed, serious accidents have occurred. 

Acetic acid content is used as a criterion for aerobic bacterial spoilage in wines. We can easily analyze two wines and determine that one has a lower volatile acidity than the other. But by every available standard of product quality judgment, the wine with the higher level of acetic acid may be the superior product. It is no accident that Subpart ZZ, Part 240, Title 26 of the Code of Federal Regulations allows the direct addition of acetic acid to correct natural deficiencies in grape wine. As sanitation practices have improved, the so-called natural acetic acid content diminished, and this has been correlated with lower consumer acceptance in certain cases (2). 

The hazard analysis of any industrial process impacts on risk assessment. Risk assessment involves the estimation of the frequency and consequences of a range of hazard scenarios and of individual and societal risk. The risk assessment process is shown in Figure 3.1. The risk criterion used in hazard analysis is the fatal accident rate (FAR). The FAR is defined as the number of fatalities per 108h exposure. The actual FAR in the U.K. was 3.5 in the chemical industry in 1975. No doubt the ideal FAR value should be zero, which is difficult to achieve in practice. 

Leachability of a waste form is perhaps the most important criterion in considering accident situations. In the absence of salts, some of our cement products may approach the low leachability of glass. After experimenting with several methods for measuring leach rates, we selected the... 

Where there is a risk of about 10 year that individuals may become casualties, steps are usually taken to reduce the risk if possible—thus, the present day concern of society to reduce the death toll from traffic accidents. As the risk diminishes, concern and countermeasures become less in evidence. For risks less than 10 year , the individual does not appear to worry much, and so elaborate precautions against the risk are seldom taken—we do not pass our lives in constant fear of being struck by lightning. Some consider that in these thoughts lies a possible clue to the level of risk from nuclear power that may be acceptable to the individual. This may well be true, and we discuss the matter further below however, experience of debate about reactor siting, and common experience of life and of the daily news which most affect people s actions and reactions may persuade us that it is the collective risk of numbers of people or a group that should provide the basis of a criterion of overriding importance in relation to risk from nuclear power. This also is discussed further in this section. 

Alcoa Work hard to prevent all accident (Health Safety Overview 2008). 1. HSE rules and criterion. 2. Believe that safety is primarily about cultural change, the ultimate objective is to institutionalize effective safety management. 3. Safety plan and behavior. 4. Indoctrinating culture of zero injuries and illnesses. 

Basically, the criterion for specifying events as accidents is that the losses are so important that they need to play a central role in the design and tradeoff process. In the outer planets explorer example in chapter 7, some of the losses involve the mission goals themselves while others involve losses to other missions or a negative impact on our solar system ecology. 

The criterion for assigning equipment to the safety system is that if it did not exist, harm to man, environment or property would have to be expected. It imphes as well a serious hazard in the sense of the Major Accident Ordinance [8]. 

In order to determine the minimum requirements for fulfilling a success criterion (e.g. 75 % of pump flow must be available for sufficient cooling) frequently information from accident simulations is used, which have been carried out in other contexts, e.g. the licensing procedure. The event tree analysis for the technical systems of a plant may be divided into two tasks ... 

The nuclides are grouped according to a criterion adopted in many source term (complex of external releases in an accident) studies. This classification takes into account important factors in the release evaluation, such as the volatility of the element or its probable compounds and their chemical/physical properties. 

However, there is no Decision Machine available, either in the form of technical guides or handbooks, and experts are frequently compelled to take subjective technical decisions and to accept the related responsibility. In fact, the practical cases are always so specific that they cannot be covered by an all-embracing handbook. Moreover, even if such a tool existed, in case of judicial trial, the compliance with the handbook could frequently be considered only an extenuation of the possible guUt of the technical expert. Historical examples exist of technical specialists who have been sentenced in a case of a pressure vessel explosion, although in due course they had verified its compliance with the technical standards in force. In case of accident, in fact, the technical expert must demonstrate the application of all the means suggested by the status of the technical knowledge . Only completely new phenomena escape this criterion. 

Single failure criterion in the form chosen (similar to the one of the IAEA criteria, that is applied to the group of systems which have to cope with an accident condition). 

In June 1985, an Italian criterion was announced (Petrangeli and Zaffiro, 1985) for the limitation of the consequences of a severe accident by simple plant modifications and by a management system of the same accidents ... 

The question that this criterion intended to answer was the following What are the maximum realistically thinkable releases, in severe accident conditions, which are consistent with the best use of the capabilities of present design plants, if a structure of accident management (procedures, equipment, training) is created ... 

Criterion 5 - Sharing of structures, systems, and components. Structures, systems, and components important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units. 

Criterion 13 - Instrumentation and control. Instrumentation shall be provided to monitor variables and systems over their anticipated ranges for normal operation, for anticipated operational occurrences, and for accident conditions as appropriate to assure adequate safety, including those variables and systems that can affect the fission process, the integrity of the reactor core, the reactor coolant pressure boundary, and the containment and its associated systems. Appropriate controls shall be provided to maintain these variables and systems within prescribed operating ranges. 

Criterion 19 - Control room. A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents. Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 5 rem whole body, or its equivalent to any part of the body, for the duration of the accident. Equipment at appropriate locations outside the control room shall be provided (1) with a design capability for prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures. 

Criterion 20 - Protection system functions. The protection system shall be designed (1) to initiate automatically the operation of appropriate systems including the reactivity control systems, to assure that specified acceptable fuel design limits are not exceeded as a result of anticipated operational occurrences and (2) to sense accident conditions and to initiate the operation of systems and components important to safety. 

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