Abstract: A method for ensuring the distribution of noble metal in the reactor circuit during plant application without measuring the reactor water for noble metal content by chemical analysis. The method involves the measurement of electrochemical corrosion potential in an autoclave or a high-flow test section that is connected to the reactor water circuit through sample lines downstream of the injection port, preferably the point in the reactor circuit which is furthest from the injection port. If the noble metal flows into the autoclave or test section at these distant points in the reactor circuit, then the noble metal will deposit on the test specimens inside the autoclave or test section.

Abstract: A device for generating direct current by neutron activation of a plurality of series-connected beta-emitter (nuclear decay electron) cells, located in the out-of-core region of a light water nuclear reactor. The device can be used as either a current source, or preferably configured as a DC voltage source, capable of powering low-power, radiation-hardened, high-temperature integrated circuitry contained in the reactor vessel. As such, the device acts like a DC battery that is activated by (n, .gamma.) reactions, both thermal and epithermal (by resonance capture). The device is not operable until exposed to a substantial neutron flux, so it has unlimited shelf-life and is not radioactive during manufacture In the preferred embodiment, an isotope of the metallic rare-earth element dysprosium is configured in a "sandwich" geometry to generate sufficient current that a useful steady voltage can be generated by means of a simple voltage regulation circuit.

Abstract: A method for mitigating crack growth on the surface of stainless steel or other metal components in a water-cooled nuclear reactor. A compound containing a noble metal, e.g., palladium, is injected into the water of the reactor in the form of a solution or suspension. This compound has the property that it decomposes under reactor thermal conditions to release ions/atoms of the noble metal which incorporate in or deposit on the interior surfaces of the crack. The compound may be organic, organometallic (e.g., palladium acetylacetonate) or inorganic in nature. The palladium deposited inside a crack should exhibit catalytic behavior even if the bulk surface palladium is depleted under high fluid flow conditions. As a result, the electrochemical potential inside the crack is decreased to a level below the critical potential to protect against intergranular stress corrosion cracking.

Abstract: A passive catalytic ammonia converter operating in the water/steam mixture exiting the core of a boiling water reactor. The catalytic ammonia converter is made of catalytic material arranged and situated such that substantially all of the water/steam mixture entering the water/steam separator device flows over the surface of the catalytic material. The catalytic surfaces react ammonia and/or NO with O.sub.2 or H.sub.2 O.sub.2 in the water/steam mixture to form nitrite or nitrate. The passive catalytic ammonia converter is constructed to ensure that the pressure drop of the reactor water across the device is very small. The catalytic ammonia converter can include a plurality of stainless steel flow-through housings packed with catalytic ammonia converter material, which could take the form of tangled wire or strips, crimped ribbon, porous sintered metal composite or any other structure having a high surface area-to-volume ratio.

Abstract: A method and an apparatus for measuring the degree of intergranular stress corrosion cracking protection in the area of the core shroud weldments. Electrochemical potential sensors are attached to the shroud wall and the upper core spray line at locations near the actual weld surface of concern to ensure the accuracy of the electrochemical potential measurements. A working electrode doped or coated with noble metal and a reference electrode are implanted into the reactor core shroud. A throughhole is drilled or machined into the shroud wall at an elevation just below the top guide support ring, i.e., near the core shroud weldments. Then a plug containing the working and reference electrodes is inserted into the throughhole.

Abstract: A passive decomposer operating in the water/steam mixture exiting the core of a boiling water reactor. The decomposer comprises a catalytic material arranged and situated such that substantially all of the water/steam mixture entering the water/steam separator device flows over the surface of the catalytic material. The catalytic decomposing surfaces decompose hydrogen peroxide molecules dissolved in the liquid phase to form water and oxygen molecules. The passive catalytic decomposer is constructed to ensure that the pressure drop of the reactor water across the device is very small. The decomposer can include a plurality of stainless steel flow-through housings packed with stainless steel catalytic decomposer material, which could take the form of tangled wire or strips, crimped ribbon, porous sintered metal composite or any other structure having a high surface area-to-volume ratio.

Abstract: In a boiling water reactor nuclear plant, hydrogen is injected into the feed water to neutralize radiolysis which causes stress corrosion in stainless steel components. It has been discovered that by inhibiting volatile ammonia, and other gaseous nitrogen compounds from leaving the liquid phase portions of the plant to the steam phase portions of the plant, radiation is reduced to acceptable levels. Formation of ammonia is inhibited chemically, by altering the reaction paths for volatile nitrogen species with trace additives in the parts per billion range, suitable additives include nitrous oxide, copper, zinc, carbon dioxide, and other components. It has also been found that by manipulating the pH, the formation of the voltage nitrogen compounds, especially ammonia, is decreased. Similarly, by physically altering plant operating conditions to reduce sparging or scrubbing of the gases from areas of high radiation, confinement of the N-16 within the liquid phase of the plant within the reactor vessel occurs.

Abstract: An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel element has a composite cladding of an outer portion forming a substrate having on the inside surface a metal layer selected from the group consisting of copper, nickel, iron and alloys of the foregoing with a gap between the composite cladding and the core of nuclear fuel. The nuclear fuel element comprises a container of the elongated composite cladding, a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, an enclosure integrally secured and sealed at each end of said container and a nuclear fuel material retaining means positioned in the cavity. The metal layer of the composite cladding prevents perforations or failures in the cladding substrate from stress corrosion cracking or from fuel pellet-cladding interaction or both.

Abstract: An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel has a composite cladding container comprising an outer layer having two coatings on the inside surface with the first coating on the outer layer being a diffusion barrier and the second coating on the first coating being a metal layer. The diffusion barrier is comprised of chromium or a chromium alloy, and the metal layer is selected from the group consisting of copper, nickel, iron and alloys thereof. The nuclear fuel element comprises a container of the elongated composite cladding, a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, an enclosure integrally secured and sealed at each end of said container and a nuclear fuel material retaining means positioned in the cavity.

Abstract: An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel element has a metal liner and a diffusion barrier disposed between the cladding and the nuclear fuel material. The diffusion barrier is in the form of a metal coating with the diffusion barrier being coated on the internal surface of the cladding in one embodiment and the diffusion barrier being coated on the outside surface of the metal liner in another embodiment. The diffusion barrier is a coating of chromium or a chromium alloy and serves to prevent any alloying or formation of low melting eutectic liquid phases between the metal liner and the cladding at elevated temperatures. The metal liner is selected from the group consisting of stainless steel, copper, copper alloys, nickel, and nickel alloys.

Abstract: A novel aqueous electrolytic activating solution and a method for electroplating zirconium and zirconium alloys are disclosed. The novel aqueous electrolytic activating solution is comprised of from about 10 to about 20 grams per liter of ammonium bifluoride (NH.sub.4 FHF) and from about 0.75 to 2 grams per liter of sulfuric acid (H.sub.2 SO.sub.4).