Westinghouse Electric Corporation

Westinghouse Electric Company LLC

Joel Woodcock

Theodore A Meyer

Robert K Perdue

Edward Terek

G Gary Elder

Warren H Bamford

J Singh Narula

An improved method of selecting and planning the performance of various maintenance activities on a facility such as a nuclear power plant includes determining the net present value of a number of future net savings that are expected to result from performance of the maintenance activity at a given time, and selecting and planning the maintenance activities in a fashion that maximizes net present value. The method includes, for each of a number of components and a number of time periods, determining a change in the probability that a component will fail within a time period, with the change resulting from an assumption that a maintenance activity is performed. The change in probability is multiplied with the losses associated with a failure in order to determine a gross savings from which costs are subtracted to determine net savings. The probabilities of failure may be determined from a probability failure model that has been derived from multiple sets of failure data that are characterized by Weibull distributions and are mathematically combined according to Bayes' Theorem. The maintenance activities may also be optimized according to a number of budget figures. An apparatus for performing the method is also disclosed.

Facility life management method

A passive nuclear power plant includes a reactor vessel enclosed by a containment shell. An in-containment cooling system piped with an out-of-containment heat sink, includes an in-containment heat exchanger vertically extending adjacent the sidewall of the containment shell for inducing natural circulation of the air in the containment shell. The heat exchanger has substantially parallel water-conducting pipes with cooling fins vertically extending therefrom for transferring heat from the naturally circulating air and for condensing steam from the atmosphere.

Nuclear power plant with containment cooling

An improved guide plate of the type used in the guide tubes of a nuclear reactor and having a central orifice for conducting coolant, and circular guide holes interconnected by slots for guidingly conducting the movement of control rodlets and control rod vanes through the guide tube is disclosed. The improvement comprises a plurality of vent openings in the form of vent holes uniformly disposed between the slots of the plate and vent gaps disposed between the outer periphery of the guide plate and the inner wall of the guide tube for reducing turbulence in the flow of coolant through the central orifice, thereby advantageously reducing both fretting and frictional engagement between the control rodlets and the guide holes. The resulting turbulence reduction further advantageously reduces the rodlet drop time through the guide tube, thereby enhancing reactor safety. Additionally, the guide holes of the improved guide plate are chrome plated to further reduce frictional engagement between the control rodlets and the plate.

Guide plate for guide tubes used in nuclear reactors

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Herminie, PA, United States of America

Joel Woodcock