ISSN:0029-5450    

DOI:10.13182/NT87-A16000

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe application of systems reliability analysis (SRA) at nuclear power plants is broadening from its initial focus on safety-related design considerations to also include operations and maintenance (O&M) issues. Effective analysis of O&M questions requires increased resources and support such as accurate and timely plant feedback. A new approach has been developed that links data from plant information management systems with systems reliability tools and models. This approach is being automated in a software system named RAPID (ReliabilityAssessmentProgram withIn-PlantData). The objective of RAPID is to provide an environment for SRA with potential for dramatically improving the quality, quantity, and timeliness of plant reliability information available for decision making, especially for O&M issues. At the same time, the system should enhance engineering efficiency by automating access to such needed resources as plant data, logic models, and evaluation codes. A developmental version of RAPID is operational at the Arizona Nuclear Power Project, where features for supporting engineering activities are being demonstrated.

ISSN:0029-5450    

DOI:10.13182/NT87-A16001

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractIn the multispectrum high convertor pressurized water reactor, the core is divided into several regions with a different moderator-to-fuel (M/F) volume ratio specified in each region. This results in a variation of the neutron spectrum in the reactor. As the average M/F ratio is low (tight-lattice configuration), the resulting spectrum in the reactor is hard and a high conversion ratio can thus be achieved. In addition, the difference in the M/F ratio allows for a better negative reactivity void response as compared to a similar monospectrum reactor. Analysis and optimization of such a reactor concept are presented and discussed.

ISSN:0029-5450    

DOI:10.13182/NT87-A16002

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA recent development in passive safety devices for advanced liquid-metal reactors is the installation of manometerlike core assemblies called gas enhancement modules (GEMs). Knowledge of the liquid sodium level within the GEMs is required to monitor GEM operation. A microwave, resonant cavity level measurement technique has been laboratory tested on a scale model of a GEM assembly in a nonsodium environment. The theory behind this method is discussed, and the experimental results are shown to compare well with those predicted by theoretical calculation. The resonant cavity level detector tracked extremely well over the desired 0.1524-to 1.1176-m range of operation and provided accurate, reproducible results well within the desired±25.4-mm actual level. When tested for vibrational stability, level errors of only 0.254 mm were observed. The effects of material differences between the experimental GEM (copper) and the actual GEM (Type 304 stainless steel) are calculated. The actual GEM will have poorer resolution but still be within±25.4-mm actual level. Temperature effects are also calculated and produce a 10.5 kHz/°C shift in resonant frequency, which could cause the indicated level to exceed the±25.4 mm allowed if large (∼149°C) temperature changes occur.

ISSN:0029-5450    

DOI:10.13182/NT87-A16003

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe preliminary analysis of an inherently safe nuclear power plant is presented. The system, based on the state-of-the-art technology of light water and gas-cooled nuclear power plants, features a multicavity prestressed concrete vessel, which houses a reduced boiling water reactor (BWR)-6 core and heat exchangers. Steam with a quality of 16.5 % at a pressure of 7.24 MPa (1050 psia) at the core exit flows through steam generators and preheaters arranged symmetrically around the core. The flow is maintained by natural circulation. Two turbine-generator-pump sets replace the high- and low-pressure injection systems as the emergency core cooling systems. The secondary system operates at a maximum pressure of 5.03 MPa (730 psia) and is rated at 1000 MW(thermal). The use of a prestressed concrete reactor vessel for ducting and containment and the replacement of forced recirculation with natural recirculation on the primary side significantly improve the inherent safety of the plant. The availability of a large thermal inventory on the primary side and the elimination of many engineered safety systems present in current BWR/pressurized water reactors should considerably simplify the operating procedures. It is expected that the modular design of the heat exchangers and the small size of the plant will reduce construction time and make it cost-effective.

ISSN:0029-5450    

DOI:10.13182/NT87-A16004

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractPast reports have estimated occurrence rates for certain multiple failure events. These reports are based on the binomial failure rate (BFR) common cause model and on licensee event report data. Uncertainty distributions for the four basic BFR parameters formed the basis of the past reports. These distributions are tabulated, and from them an analyst can estimate, with uncertainty bounds, the rate or probability of a quite arbitrary multiple failure event. No longer is there a restriction to those events for which rates have been published.

ISSN:0029-5450    

DOI:10.13182/NT87-A16005

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe critical experiments reported provide data for the effect of a soluble neutron absorber (cadmium nitrate) on the criticality of high-enriched uranium nitrate solution. These data can be used in criticality control and for validation of calculational methods. The experiments were performed with cylindrical vessels of two different diameters, 241.8 and 291.6 mm. Cadmium concentrations used in the high-enriched uranium solution ranged up to∼11 g Cd/ℓ. The vessels were reflected with water, and in some cases with water containing dissolved cadmium nitrate.The cadmium was found to be an effective neutron absorber when dissolved in the solution. The critical experiment data were analyzed by several different calculational methods, which showed the calculated keffvalues to increase as the cadmium concentration was increased. (The critical system calculated as supercritical.) The trend of the analysis results suggests that the neutron leakage or cadmium absorption may be underestimated for systems with a harder neutron spectrum.

ISSN:0029-5450    

DOI:10.13182/NT87-A16006

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA brief survey of the safety analyses procedure for the operational and post-operational phase of the planned German“Konrad”repository is given. The geological formation that is planned only for the disposal of radioactive waste with negligible heat production is an iron ore bed. In the framework of the safety analyses, waste acceptance criteria are derived. These criteria concern the waste form, the waste packaging, and the radionuclide inventory. The potential radiation exposure during the operational and postoperational phase is given.

ISSN:0029-5450    

DOI:10.13182/NT87-A16007

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA computer program is developed to simulate the fluid and thermal mixing of the Electric Power Research Institute/Creare one-fifth-scale tests. The mass-flow-weighted skew-upwind differencing scheme (SUDS), as well as the upwind differencing scheme, and the k-∈two-equation model of turbulence in cylindrical coordinates are employed in the numerical simulation. The computational results are compared with experimental data of test numbers 42, 46, and 51 and COMMIX results. The numerical diffusion is significantly reduced by SUDS, and a satisfactory prediction is achieved.

ISSN:0029-5450    

DOI:10.13182/NT87-A16008

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe thermodynamic solubility of PuO2in nitric acid has been calculated, taking into account the formation of higher nitrate complexes of plutonium at higher acidities. The dissolution of PuO2in nitric acid containing hydrofluoric acid and hydrazine has been studied. The results indicate that the presence of hydrazine in nitric acid containing hydrofluoric acid aids the dissolution of PuO2. The destruction of hydrazine after the dissolution step is found to be easy.

ISSN:0029-5450    

DOI:10.13182/NT87-A16009

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor