Safety plant operation

ESCIS (Expert Commission for Safety in the Swiss Chemical Industry), Static electricity rules for plant safety, Plant/Operations Prog., 7 1-22 (1988)... 

Expert Commission for Safety in Swiss Chemical Industry, Static Electricity Rules for Plant Safety, Plant/Operations Progress (January 1988), 7(1) 1. 

Crowl, D. A., and J. F. Louvar, "Instructional Videotapes on Chemical Process Safety," Plant/Operations Progress, 8,225 (1989). 

Thermal power plant components operated at high temperatures (>500°C) and pressures, such as superheater headers, steamline sections and Y-junctions, deserve great attention for both operation safety and plant availability concerns. In particular, during plant operation transients -startups, shutdowns or load transients - the above components may undergo high rates of temperature / pressure variations and, consequently, non-negligible time-dependent stresses which, in turn, may locally destabilize existing cracks and cause the release of acoustic emission. 

The development and improvement of scientific-technical level of NDT and TD means for safety issues is connected with the necessity to find additional investments that must be taken into account at the stage of new technogenic objects designing, when solving new arising problems in social, economic, ecological and medical safety. It is not accidental, that the expenses for safe nuclear power plants operation cover 50% of total sum for construction work capital investments. That is why the investments for NDT and TD have to cover 10% of total amount for development and manufacturing of any product. 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

A technique called probabiUstic safety assessment (PSA) has been developed to analy2e complex systems and to aid in assuring safe nuclear power plant operation. PSA, which had its origin in a project sponsored by the U.S. Atomic Energy Commission, is a formali2ed identification of potential events and consequences lea ding to an estimate of risk of accident. Discovery of weaknesses in the plant allows for corrective action. 

Audits by INPO and the U.S. NRC aie a culmination of a high degree of self-auditing by the plant operators and the utihties themselves, often assisted by special third-party safety review boards set up to help carry out safety assessments (21). Self-auditing and self-criticism are essential to the process. These reflect the fundamental reactor safety principle that the owner-operator of the plant has the ultimate responsibiUty for plant safety. 

The World Association of Nuclear Operators (WANO) has been formed, consisting of nuclear plant operators over the entire world who have pledged to assist each other in the achievement of safe operations (25). There are four centers from which this international program is adrninistered one in the United States in Atlanta, Georgia, operated by INPO one in Paris operated by Electricitir de Prance one in Moscow operated by the Ministry of Nuclear Power and one in Tokyo operated by the Central Research Institute for the Electric Power Industry (CRIEPI). Through this mechanism, teams of operators from the U.S., Western Europe, and Asia visit CIS plants to share safety experience and know-how, and similarly, plant personnel from Russian and Eastern European nuclear units visit European, Asian, and U.S. plants. 

The sum total of risks of the nuclear fuel cycle, most of which are associated with conventional industrial safety, are greater than those associated with nuclear power plant operation (30,35—39). However, only 1% of the radiological risk is associated with the nuclear fuel cycle so that nuclear power plant operations are the dominant risk (40). Pubhc perception, however, is that the disposition of nuclear waste poses the dominant risk. 

The development of computer capabiUties in hardware and software, related instmmentation and control, and telecommunication technology represent an opportunity for improvement in safety (see COMPUTER TECHNOLOGY). Plant operators can be provided with a variety of user-friendly diagnostic aids to assist in plant operations and incipient failure detection. Communications can be more rapid and dependable. The safety control systems can be made even more rehable and maintenance-free. Moreover, passive safety features to provide emergency cooling for both the reactor system and the containment building are being developed. 

Pilot plants are often more hazardous than process plants, even though they are smaller ia size, for many reasons. These iaclude a tendency to relax standard safety review procedures based on the small scale, exceptionally qualified personnel iavolved, and the experimental nature of the research operations the lack of estabhshed operational practice and experience lack of information regarding new materials or processes and lack of effective automatic iatedocks due to the frequendy changing nature of pilot-plant operations, the desire for wide latitude in operating conditions, and the lack of hill-time maintenance personnel. 

Process Safety Eundamentals for General Plant Operations... 

Plant Operations Progress, Vols. I—II, American Institute of Chemical Engineers, 1982—1992 Process Safety Progress, Vol. 12, 1993—present. 

Eault tree analysis (ETA) is a widely used computer-aided tool for plant and process safety analysis (69). One of the primary strengths of the method is the systematic, logical development of the many contributing factors that might result ia an accident. This type of analysis requires that the analyst have a complete understanding of the system and plant operations and the various equipment failure modes. 

Unless some discipline is imposed, engineering personnel, especially where contractors are involved, will define far more alarms than plant operations require. This situation may be addressed by simply setting the alarm hmits to values such that the alarms never occur. However, changes in alarms and alarm hmits are changes from the perspec tive of the Process Safety Management regulations. It is prudent to impose the necessary discipline to avoid an excessive number of alarms. Potential guidelines are as follows ... 

Facilities Reviews There are many lands of facilities reviews that are useful in detec ting and preventing process safety problems. They include pre-start-up reviews (before the plant operates), new-plant reviews (the plant has started, but is stiU new), reviews of existing plants (safety, technology, and operations audits and reviews), management reviews, critical instrument reviews, and hazardous materials transportation reviews. 

The goal of plant-performance analysis is to improve understanding, efficiency, quahty, and safety of operating plants. The end use must be... 

Plant Operation The purpose is to maintain and improve performance (i.e., product quality, rate, efficiency, safety, and profits). Examples include identification of plant conditions that limit performance (troubleshooting, debottlenecking) and exploration of new operating regions. 

CCPS G-22. Guidelines for Process Safety Eundamentals for General Plant Operations. American Institute of Chemical Engineers, Center for Chemical Process Safety, New York. 

The use of electrochemical protection in the chemical industry started about 20 years ago, which is somewhat recent, compared with its use for buried pipelines 40 years ago. Adoption was slow because the internal protection has to be tailored to the individual plant, which is not the case with the external protection of buried objects. Interest in internal protection came from the increasing need for greater safety for operating plants, increased demands for corrosion resistance, and larger plant components. While questions of its economy cannot generally be answered (see Section 22.6), the costs of electrochemical protection are generally less than the cost of equivalent and reliable coatings or corrosion-resistant materials. 

Working with a Process Hazards Analysis (PHA) team was particularly rewarding. The plant operators on the team pointed out items that they had considered safety problems for years, but that hadn t been fully addressed until the PHA team was formed. We used the What if analysis method. Many methods are available for PHA. 

ORP Oxidation reduction potential - the degree of completion of a chemical reaction by detecting the ratio of ions in the reduced form to those in the oxidized form as a variation in electrical potential measured by an ORP electrode assembly. OSHA The Williams-Steiger Occupational Safety and Health Act of 1970 (OSHA) is a law designed to protect the health and safety of industrial workers and treatment plant operators. It regulates the design, construction, operation and maintenance of industrial plants and wastewater treatment plants. The Act does not apply directly... 

It is hoped that this volume will provide some guidance to operators, plant safety engineers and designers, and that some of the design practices are adopted particularly in older plant operations that do not apply proper pressure let down procedures and flaring practices. Many unsafe operations and even catastrophic failures have been observed by the author in overseas assignments to such countries as Ukraine and other Newly Independent States (NIS) in older plant designs. These incidents have prompted the preparation of this reference. 

The Safety Goal Policy Statement was published to define acceptable radiological risk IVom nuclear power plant operation, and by implication provide a de minimus risk to be assured without cost considerations. Safety beyond the minimum requires cost-benefit analysis. Since being promulgated, bulletins and generic letters have been imposed to enhance safety, under the provisions of 10 CFR 50.109, the Backfit Rule. 

Risk-based information provides a foundation for regulation of severe accidents. Early PRAs, with large uncertainties, indicated risk that was above or below the Safety Goals depending on containment performance. Consequently the NRC developed an Integration Plan for Closure of Severe Accident Issues (SECY-88-47) with six main elements to this plan 1) individual plant examinations (IPE), 2) containment performance improvements, 3) improved plant oper itions, 4) severe accident research, 5) external event considerations, and 6) accident management. 

Blond, R., The Development Severe Reactor Source Terms 1957-1981, November 1982. Safety Goals for Nuclear Power Plant Operation May 1983. 

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