Mitigated accident consequence

An FPS actuation which results in an adverse interaction with the safety systems of the plant or the secondary effects of a fire could reduce the availability of systems needed to achieve and keep safe plant shutdown conditions or to mitigate accident consequences. 

High design pressure of SG and secondary system. Feed / steam system designed for reactor coolant system pressure. No SG safety valve. SG transient Section isolation mitigates accident consequences... 

A chemical property, energy source, or physical condition that has the potential to cause illness, injury, or death to personnel, or damage to property or to the environment, without regard for the likelihood or credibility of potential accidents or the mitigation of consequences. 

An event of an accident event sequence that helps to propagate tlie accident or helps to prevent the accident or mitigate tlie consequences. 

None of the munitions at Pueblo contains M28 propellant therefore, this incident has no direct bearing on planned disposal activities at Pueblo. However, the incident does show that even though the maximum credible event may not result from every process upset, sound engineering practices must always be used. This will reduce the likelihood of an accident and mitigate the consequences of accidents that do occur. The incident also highlights the need for training personnel involved in such operations to become aware of all possible hazards. 

In the year 1984, the Directive to the European Commission established an industrial accident notification scheme, the MARS, operated and maintained by the Major Accident Hazards Bureau of the Commission s Joint Research Center in Ispra, Italy. The objective is to use this information as a basis from which to draw lessons learned for preventing major accidents and mitigating then-consequences. 

Radiation standardization, forecasting, and control of the radiation situation in the vicinity of the accident site, and interdepartmental interaction in the post-accident period to mitigate the consequences of the radiation disaster (provided any items of nuclear weapons have been destroyed) are the most urgent problems to be practically solved in the future. 

SSCs that prevent imsafe conditions or that mitigate the consequences of anticipated operational occurrences and accident conditions ... 

Measures of hazard defence are intended to mitigate the consequences of accidents. Among them figure the following measures, where of course only the active systems are triggered by PCE equipment. 

SSCs which are used in plant emergency operating procedures (EOPs) or are relied on to mitigate the consequences of transients or beyond design basis accidents. 

The surveillance of safety systems should cover systems and components provided to shut down the reactor and keep it shut down, and to ensure that safety limits are not exceeded either owing to anticipated operational occurrences or during the initial operation of systems that are required in order to mitigate the consequences of accident conditions. Such mitigation could be done through ... 

All SSCs with functions that mitigate the consequences of accident conditions should be subject to periodic surveillance, to demonstrate their availability... 

Engineered Safety Features means systems, components, or structures that prevent and/or mitigate the consequences of potential accidents described in the FSAR including the bounding design basis accidents. 

DISCUSSI ON. The reactor design should be fundamentally safe to ensure that the reactor is capable of being shutdown safely and adequately cooled following postulated accidents. In addition, the reactor facility should be designed to provide defense-in-depth needed to prevent or mitigate the consequences of accidents that could result in uncontrolled release of radioactive materials to the environment. The nuclear safety design criteria ensure that the reactor and the associated safety class SSCs perform their intended safety functions. 

The Technical Safety Objective is to take all reasonably practicable measures to prevent accidents in nuclear installations and to mitigate their consequences should they occur to ensure with a high level of confidence that, for all possible accidents taken into account in the design of the installation. 

In nuclear power plants, the containment is the final barrier that prevents radioactive release to the environment during accident events. Because of containment importance in mitigating the consequences of an accident, it is necessary not only to assess its integrity during an accident, but also to ensure that it is and stays leakproof after the accident has occurred. 

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. 

Level 4 Control of the severe accident conditions of the plant, including the prevention of accident progression and mitigation of consequences. Additional measures and accident management. 

The hazard analysis considers the complete spectrum of accidents that may occur due to operations at the facilities, analyzes potential accident consequences to the public and workers, estimates the likelihood of accidents occurring, identifies and assesses associated preventive and mitigative features, and identifies bounding accident scenarios. Subsequent accident analysis evaluates the bounding accident scenarios for comparison vwth DOE Evaluation Guidelines. The scope and format of this chapter is consistent with DOE-STD-3009-94. 

Each of these features provides a safety benefit, however not all of these features are necessary to mitigate dose consequences to acceptable levels. Only those features that are relied upon to function or actuate to prevent or mitigate uncontrolled releases of radioactive materials are so identified. Analyses accomplished to evaluate the consequences of release of radiological materials, described in Section 3.4, identify those SSC s that are part of the primary success path in each scenario. The SSC s so identified are associated with a significant mitigation of radiological releases in abnormal and accident scenarios and therefore perform a defense in depth Safety Function. 

This section contains a summary of all SSCs and administrative controls that have been identified in Chapters 3 and 4 as necessary for 1) maintaining the consequences of facility operations below the 25 rem off-site Evaluation Guideline (EG), or 2) providing significant defense in depth or worker safety because they either reduce e likelihood or mitigate the consequences of an accident. 

This section identifies those design features from the hazard or accident anaiysis which are considered passive in nature, but which provide a safety function to either prevent or mitigate the consequences of postulated accident scenarios. 

The response actions required of TA-V personnel in the event of an accident or abnormal event are discussed in the TA-V EPP. All personnel within the TA-V perimeter are instructed to evacuate the TA-V facilities and proceed to the assembly building over prescribed routes unless specifically exempted for a particular critical operation. Members of the various TA-V emergency teams report to their EPP designated locations. The short evacuation time coupled with the generally low inventory of radioactive or other hazardous materials and the inherent shielding of the structure provides an effective mechanism for mitigating the consequences of an accident. 

Two distinctly different, yet complementary, perspectives of hazards for the HCF and associated radioactive material storage locations are obtained for the overall hazard analysis of Chapter 3 by using both PHA and failure mode effects analysis (FMEA) techniques. FMEA is a complementary type of evaluation that utilizes a system failure-based form of analysis. Unlike PHA, the first objective of FMEA is to subdivide the facility Into several different (and, to the maximum extent possible, independent) system elements. Failure modes of each system element are then postulated and a structured examination of the consequences of each failure mode follows. However, similar to PHA, FMEA documents preventive and mitigative features (failure mechanisms and compensation) and anticipated accident consequences (failure effects). Appendix 3D contains the FMEA for the HCF. 

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