The establishment of the time interval between inspections for a cold standby system with component repair

The time interval between inspections of cold standby systems is a crucial decision to ensure the appropriated system reliability and the lowest costs possible. This paper presents a model developed to establish the optimal time interval between inspections for a two-unit cold standby system with component repair and subject to periodic inspection, considering reliability and costs. A Markov chain is used to define possible states, their transition probabilities and the mean time to system failure, as a function of the time interval between inspections. Given the mean time to system failure, the steady state availability is determined. Finally, the costs related to the system maintenance are established and a cost function is developed and optimized for the time interval between inspections. Numerical examples are presented and results for different system parameters are compared. Besides optimizing the time interval between inspections, the analyses also reveal the effect of repair time on system availability and mean time to system failure

Study of Space Station propulsion system resupply and repair Final report

Resupply and repair capabilities for orbital space station bipropellant propulsion syste

Study of space shuttle environmental control and life support problems

Four problem areas were treated: (1) cargo module environmental control and life support systems; (2) space shuttle/space station interfaces; (3) thermal control considerations for payloads; and (4) feasibility of improving system reusability

1998 FFTF annual system assessment reports

The health of FFTF systems was assessed assuming a continued facility standby condition. The review was accomplished in accordance with the guidelines of FFTF-EI-083, Plant Evaluation Program. The attached document includes an executive summary of the significant conclusions and assessment reports for each system evaluated

Aircraft cabin water spray disbenefits study

The concept of utilizing a cabin water spray system (CWSS) as a means of increasing passenger evacuation and survival time following an accident has received considerable publicity and has been the subject of testing by the regulatory agencies in both the United States and Europe. A test program, initiated by the CAA in 1987, involved the regulatory bodies in both Europe and North America in a collaborative research effort to determine the benefits and 'disbenefits' (disadvantages) of a CWSS. In order to obtain a balanced opinion of an onboard CWSS, NASA, and FAA requested the Boeing Commercial Airplane Group to investigate the potential 'disbenefits' of the proposed system from the perspective of the manufacturer and an operator. This report is the result of a year-long, cost-sharing contract study between the Boeing Commercial Airplane Group, NASA, and FAA. Delta Air Lines participated as a subcontract study team member and investigated the 'return to service' costs for an aircraft that would experience an uncommanded operation of a CWSS without the presence of fire. Disbenefits identified include potential delays in evacuation, introduction of 'common cause failure' in redundant safety of flight systems, physiological problems for passengers, high cost of refurbishment for inadvertent discharge, and potential to negatively affect other safety systems

Requirement Specification for Station Blackout Gas Turbine Generator in a Nuclear Power Plant

The ultimate purpose of nuclear power plant safety systems is to prevent damage to the reactor and the possible release of radioactive materials into the surroundings following an internal or external event that interrupts normal power plant operation. Different design principles have been developed and they are incorporated to the safety design to ensure the safety functions are performed even if some components or whole systems fail to function as intended. Many nuclear power plant safety systems rely on electrical power to operate. Following a loss of off-site power accident, the power plant electrical systems are supplied by the emergency power sources. Station blackout generators constitute an alternative source for AC power designed for situations where all the main emergency diesel generators a fail to function in accident conditions. To introduce diversity into the emergency power sources, gas turbine generator units are proposed to be used instead of diesel generators as station blackout power sources. Current nuclear regulations regarding the emergency power generating facilities in a nuclear power plants only consider diesel engines for the application. The motivation for this research is the absence of a national or a global standard for the design and acceptance testing of gas turbines in this application. In this thesis the main goal is to determine the requirements for a station blackout gas turbine generator so that it fulfils its role in the overall nuclear power plant safety system design. The requirement specifications composed as part of this thesis covers the requirements for design, operation, maintenance, qualification and testing of the station blackout emergency power facility including the facility layout, gas turbine engine, generator, instrumentation and control systems and auxiliary support systems such as fuel and lubrication systems. The decisions behind the technical or quality requirements will be explained and discussed to justify the chosen requirements

A surveillance strategy for four year operating cycle in commercial pressurized water reactors

Thesis (Nucl. E.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996.by Thomas Joseph Moore, Jr.Nucl.E