Sensor for controlling water quality of reactor and method of

Abstract

An element (e.g., a sensor) has a fine-line thin film of a conductor formed on a non-conductive substrate, and a change of physical properties (e.g., deformation) of the substrate or the ambient environment is detected through a change in physical properties of the conductor. The element is manufactured by forming a layered film, composed of a semiconductor and a conductor, on the substrate, and forcibly diffusing part of this film, e.g., by selective irradiation with high-energy ions, to form this part into an alloy semi-conductor, thereby providing a two-dimensional pattern of the fine lines of the conductor and the semiconductor. By arranging a plurality of fine lines of a conductor transversely to a direction of growth of a crack in the substrate, crack in the substrate is detected through a change in electrical resistance of the fine lines. A dissolved oxygen sensor, a hydrogen sensor, and an electrical conductivity sensor (of an ambient medium) can also be provided. To control water chemistry of a reactor, an amount of a water chemistry improving agent injected is controlled in accordance with an output of a water chemistry measurement sensor provided in water in a pressure vessel of the reactor. One or more of a dissolved oxygen sensor, a hydrogen sensor and an electrical conductivity sensor are formed directly on a surface of a structural material of the reactor.