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定价： 345元 / 折扣价： 294 元

定价： 260元 / 折扣价： 221 元

定价： 260元 / 折扣价： 221 元

定价： 345元 / 折扣价： 294 元 加购物车

4.1 Nuclear grade graphite is a composite material made from petroleum or a coal-tar-based coke and a pitch binder. Manufacturing graphite is an iterative process of baking and pitch impregnation of a formed billet prior to final graphitization, which occurs at temperatures greater than 2500 °C. The impregnation and rebake step is repeated several times until the desired product density is obtained. Integral to this process is the use of isotropic cokes and a forming process (that is, isostatically molded, vibrationally molded, or extruded) that is intended to obtain an isotropic or near isotropic material. However, the source, size, and blend of the starting materials as well as the forming process of the green billet will impart unique material properties as well as variations within the final product. There will be density variations from the billet surface inward and different physical properties with and transverse to the grain direction. Material variations are expected within individual billets as well as billet-to-billet and lot-to-lot. Other manufacturing defects of interest include large pores, inclusions, and cracks. In addition to the material variation inherent to the manufacturing process, graphite will experience changes in volume, mechanical strength, and thermal properties while in service in a nuclear reactor along with the possibility of cracking due to stress and oxidation resulting from constituents in the gas coolant or oxygen ingress. Therefore, there is the recognized need to be able to nondestructively characterize a variety of material attributes such as uniformity, isotropy, and porosity distributions as a means to assure consistent stock material. This need also includes the ability to detect isolated defects such as cracks, large pores and inclusions, or distributed material damage such as material loss due to oxidation. The use of this guide is to acquire a basic understanding of the unique attributes of nuclear grade graphite and its application that either permits or hinders the use of conventional eddy current, ultrasonic, or X-ray inspection technologies.1.1 This guide provides general tutorial information regarding the application of conventional nondestructive evaluation technologies (NDE) to nuclear grade graphite. An introduction will be provided to the characteristics of graphite that defines the inspection technologies that can be applied and the limitations imposed by the microstructure. This guide does not provide specific techniques or acceptance criteria for end-user examinations but is intended to provide information that will assist in identifying and developing suitable approaches.1.2 The values stated in SI units are to be regarded as the standard.1.2.1 Exception—Alternative units provided in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 / 折扣价： 550 元 加购物车

This specification covers blended uranium oxides with a 235U content of less than 5% for direct hydrogen reduction to nuclear grade uranium dioxide. For commercial-grade uranium oxide with an isotopic content of 235U between that of natural uranium and 5%, the isotopic limits shall apply. Physical and chemical requirements include: uranium content, oxygen-to-uranium ratio, impurity content, equivalent boron content, bulk density, moisture content, ability to flow, particle size, and reduction and sinterability. Maximum concentration limit is specified for impurity elements such as: aluminum, barium, beryllium, bismuth, calcium+magnesium, carbon, chlorine, chromium, cobalt, copper, fluorine, iron, lead, manganese, molybdenum, nickel, phosphorus, silicon, sodium, tantalum, thorium, tin, titanium, tungsten, vanadium, and zinc. The identity of a lot shall be retained throughout.1.1 This specification covers blended uranium trioxide (UO3), U3O8, or mixtures of the two, powders that are intended for conversion into a sinterable uranium dioxide (UO2) powder by means of a direct reduction process. The UO2 powder product of the reduction process must meet the requirements of Specification C 753 and be suitable for subsequent UO2 pellet fabrication by pressing and sintering methods. This specification applies to uranium oxides with a 235U enrichment less than 5 %.1.2 This specification includes chemical, physical, and test method requirements for uranium oxide powders as they relate to the suitability of the powder for storage, transportation, and direct reduction to UO2 powder. This specification is applicable to uranium oxide powders for such use from any source.1.3 The scope of this specification does not comprehensively cover all provisions for preventing criticality accidents, for health and safety, or for shipping. Observance of this specification does not relieve the user of the obligation to conform to all international, national, state, and local regulations for processing, shipping, or any other way of using uranium oxide powders (see 2.2 and 2.3).1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 The following safety hazards caveat pertains only to the test methods portion of the annexes in this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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1.1 This specification defines the physical and chemical requirements for hafnium oxide powder intended for fabrication into shapes for use in a nuclear reactor core.1.2 The material described herein shall be particulate in nature.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 The results of this test method give a conservative estimate of the performance of nuclear-grade activated carbon used in all nuclear power plant HVAC systems for the removal of radioiodine.1.1 This test method is a very stringent procedure for establishing the capability of new and used activated carbon to remove radio-labeled methyl iodide from air and gas streams. The single test method described is for application to both new and used carbons, and should give test results comparable to those obtained from similar tests required and performed throughout the world. The conditions employed were selected to approximate operating or accident conditions of a nuclear reactor which would severely reduce the performance of activated carbons. Increasing the temperature at which this test is performed generally increases the removal efficiency of the carbon by increasing the rate of chemical and physical absorption and isotopic exchange, that is, increasing the kinetics of the radioiodine removal mechanisms. Decreasing the relative humidity of the test generally increases the efficiency of methyl iodide removal by activated carbon. The water vapor competes with the methyl iodide for adsorption sites on the carbon, and as the amount of water vapor decreases with lower specified relative humidities, the easier it is for the methyl iodide to be adsorbed. Therefore, this test method is a very stringent test of nuclear-grade activated carbon because of the low temperature and high relative humidity specified. This test method is recommended for the qualification of new carbons and the quantification of the degradation of used carbons.1.1.1 Guidance for testing new and used carbons using conditions different from this test method is offered in Annex A1.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 / 折扣价： 550 元 加购物车