Criticality-Safety Requirements

In the NSD, vast experience has been gained regarding the application of computational methods for determining nuclear safety parameters, both for separate pieces of equipment of various types and for entire installations. For instance, the experts from this division participated in working out the criticality safety requirements for the RT-1 plant (Mayak), which is currently in operation, and used them in designing the RT-2 plant. 

The SNL Criticaiity Safety program requires the preparation of activity-specific Criticality Safety Assessments (CSAs) for storage and handling of threshold quantities of fissile material. The CSAs are individually reviewed and approved as the Facility mission dictates. The CSA for Mo-99 is typical of the analyses performed to determine criticality safety requirements therefore, references to the Mo-99 CSA in the follovinng sections are intended to provide an example of how the Criticality Safety program generates operational commitments. 

Criticality safety requirements have been identified and implemented for the safe storage of special nuclear material and... 

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. 

As the nuclear ftiel recycle industry grows, the probability of a criticality accident will tend to grow proportionately unless current criticality safety control is improved. (Accident Probability < Probability per Plant times Number of Plants.) Optimum control of criticality safety requires an overview of the entire system. The relationships between the criticality safety philosophy, the criticality data, the use of the data, and various human Victors must be considered. Application of the foult tree analysis (FTA) methodology will permit identification of the important control foctors and their relationships, indication of what is required to reduce the accident probability per plant, and systematic evaluation of our current criticality safety position. FTA is not new but the application to criticality safety presented in this... 

MORT can be equally useful and even more valuable, however, as an analytical tool to reduce or eliminate potential sources of accidents. Such uses have been frequent, but not widespread moreover, their application to criticality safety problems, with certain exceptions, has been neglected. Yet criticality safety requires the kind of thorou, highly disciplined, and carefuUy documented analysis that can be greatly strengthened by the use of MORT techniques. In addition, the author believes that training criticality safety professionals in the use of MORT early in their careers would not. only speed up their ability to use their formal training effectively, but would induce, at an early st in their career, those mental attitudes and disciplines prerequisite to effective performance. 

Procedures for assurance of quality in the design, fabrication, installation, maintenance, testing and inspection for critical equipment are ) red. Safety requires that critical safety devices must operate as i led and process system components must be maintained to be able to contain design pressures. 

However, like with metals, there are many stresses that cannot be accurately analyzed. Hence one is forced to rely on properties that correlate with performance requirements. Where the product has critical performance requirements, such as ensuring safety to people, production prototypes will have to be exposed to the requirements it is to meet in service. 

Despite the extensive investigations that must be undertaken prior to placing a drug on the market, it is not possible to guarantee that all safety issues have been identified. Thus, market vigilance systems must be maintained after a dmg has been launched so as to detect safety issues that were not evident prior to commercialisation. For such systems to be effective requires the participation and cooperation of the medical profession, the pharmaceutical industry and the regulators, in order that critical safety information can be identified and acted on in a timely manner. In some... 

Both qualitative and quantitative evaluation techniques may be used to consider the risk associated with a facility. The level and magnitude of these reviews should be commensurate with the risk that the facility represents. High value, critical facilities or employee vulnerability may warrant high review levels. While unmanned "off-the-shelf, low hazard facilities may suffice with only a checklist review. Specialized studies are performed when in-depth analysis is needed to determine the cost benefit of a safety feature or to fully demonstrate the intended safety feature has the capability to fully meet prescribed safety requirements. 

Description of all important and critical specifications of the system, like process parameter, technical parameters, safety requirements, environmental requirements, and GMP-relevant specifications. 

Such considerations allow adapting the equipment or the process, that is, the degree of filling of the reactor, to the safety requirements. This kind of measure often allows running processes under safe conditions, whereas a standard assessment would consider them as critical. They are based both on easily accessible physico-chemical properties of the boiling solvent and on geometric data of the reactor. 

As a conclusion, it appears clear that measures must be taken to avoid omitting the charging of compound (A) the omission of (B) is not as critical, and requires no special measure. Thus, based on two dynamic DSC thermograms, important conclusions for the safety of the studied process can be drawn. 

Work is ongoing to develop less onerous codes and standards, but for now they greatly complicate hydrogen infrastructure efforts. Fuel-cell vehicles will require modifications to garages, maintenance facilities, and on-road infrastructure [such as tunnels] that could be costly and difficult to implement as the A. D. Little report noted. Implementation of critical safety measures for closed... 

The eritieal safety proeess parameters need to be determined and, in conjunction with statutory requirements, applied to the SCADA system. The manner in which the SCADA system addresses the critical safety proeess parameters needs to be evaluated and an outcome determined that ensures that the safety parameters are aeeurately monitored and controlled. 

Electronic records requiring particular regulatory control should be identified based on critical process control points and associated critical parameters that directly impact product quality or product safety. A defined process should be used to conduct this analysis, and it should be one that builds on or is complementary to any assessment conducted as part of product registration. Consistency is key. There may be additional records identified by predicate rules but care must be taken not to extend beyond these records. A risk assessment should be conducted to determine appropriate electroific record management controls such as audit trail and archiving. Electronic records will need to be archived for retention periods specified in predicate rules. Other data related to process performance rather than product quality or product safety requires only basic data maintenance and may be retained for much shorter periods before being purged. 

A High Furnace Temperature Interlock is required by NFPA 86 (sect. 5-16) whenever it is possible for the controlled temperature to exceed a safe limit. The high-temperature interlock device and associated equipment including thermocouple must be independent of the equipment used to control the temperature of the furnace. The high furnace temperature interlock is considered a critical safety interlock. 

Sub-sections 9.1 and 9.2 described the materials and designs for cables that are intended for general use. The oil industry has additional requirements for cables that may be routed in normal hot surroundings, in areas where a fire situation must be tolerated and for the emergency control of critical safety circuits and systems. Examples of these situations are,... 

This safety requirement, however, cannot be applied directly as an assessment criterion, as the exact place along the pipe at which the temperature maximum will occur is not known. This knowledge would be the prerequisite for the determination of the conversion, wdiich itself is required for the calculation of rwaii- If rwait were known, it could be used in combination with all other substance and equipment data to calculate the critical pipe diameter and to compare it with the actual diameter. This way the radial temperature profile could be estimated. Figure 4-36 shows a theoretical example. 

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