scholarly journals Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

10.2172/4931 ◽  
1998 ◽  
Author(s):  
N.J. Lowry
Keyword(s):  
Heavy Water ◽  
Analytical Study ◽  
High Concentration ◽  
Test Reactor

Analytical Study of Fatigue Cracking in Coped Stringers of Steel Bridges

2019 ◽  
Vol 2673 (10) ◽  
pp. 239-246
Author(s):  
Alireza Mohammadi ◽  
Walid S. Najjar
Keyword(s):  
Tensile Stress ◽  
Stress Reduction ◽  
Analytical Study ◽  
Three Dimensional ◽  
Fatigue Cracking ◽  
Hole Drilling ◽  
Finite Element Models ◽  
High Concentration ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Typical coped stringers of streel bridges are prone to fatigue cracking as a result of the high concentration of tensile stress in the cope zone. This stress concentration is caused by a combination of geometric discontinuity at the cope radius and end-connection rigidity. Few retrofit methods are available for mitigating this cracking; they include hole drilling at a crack tip, and top-rivet removal from a stringer-floorbeam connection. Three-dimensional finite element models of a typical stringer with coped web were developed and analyzed to evaluate (i) cope geometry and load configuration parameters and (ii) the effectiveness of these two retrofit methods. The studied geometry parameters were cope radius and cope length. Variations in the cope-zone stress distribution for each parameter and between an original and a retrofitted condition are presented in this paper. Tensile stress reduction was associated with increased cope radius. Although hole drilling resulted in significant stress reduction along the cope edge, this method was associated with increased tensile stress at the bottom of the drilled hole, which could result in further crack propagation. This finding is consistent with existing studies. Removal of a top rivet resulted in significant reduction of tensile stress.

Sensitivity Degradation Characteristics of Incore Neutron Detector for Heavy Water Reactor, Fugen NPP

2002 ◽  
Author(s):  
Tsuyoshi Okawa ◽  
Naoyuki Yomori
Keyword(s):  
Thermal Neutron ◽  
Heavy Water ◽  
Power Distribution ◽  
Neutron Detector ◽  
Nuclear Power ◽  
Operating Cost ◽  
Water Reactor ◽  
Mox Fuel ◽  
Heavy Water Reactor ◽  
Test Reactor

Fugen nuclear power plant is a 165MWe, heavy water-moderated, boiling light water-cooled, pressure tube-type reactor developed by JNC, which is the world’s first thermal neutron power reactor to utilize mainly Uranium and Plutonium mixed oxide (MOX) fuel. Fugen has been loaded a total of 726 MOX fuel assemblies since the initial core in 1978. Each incore neutron detector assembly of Fugen composed of four Local Power Monitors (LPM) is located at sixteen positions in the area of heavy water moderator in the core and monitors its power distribution during operation. The thermal neutron flux of Fugen is relatively higher than that of Boiling Water Reactor (BWR), therefore LPM, which is comprised of a fission chamber, degrades more quickly than that of BWR. An Improved Long-life LPM (LLPM) pasted inner surface wall of the chamber with 234U/235U at a ratio of 4 to 1 had been developed through the irradiation test at Japan Material Test Reactor (JMTR). The 234U is converted to 235U with absorption of neutron, and compensates the consumption of 235U. LPM has been loaded to the initial core of Fugen since 1978. JNC had evaluated its sensitivity degradation characteristics through the accumulated irradiation data and the parametric survey for 234σa and 235σa. Based on the experience of evaluation for sensitivity degradation, JNC has applied shuffling operation of LPM assemblies during an annual inspection outage to reduce the operating cost. This operation realizes the reduction of replacing number of LPM assemblies and volume of radioactive waste. This paper describes the sensitivity degradation characteristics of incore neutron detector and the degradation evaluation methods established in Fugen.

Results of Tests to Demonstrate a 6-in.-Diameter Coater for Production of TRISO-Coated Particles for Advanced Gas Reactor Experiments

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Charles M. Barnes ◽  
Douglas W. Marshall ◽  
Joe T. Keeley ◽  
John D. Hunn
Keyword(s):  
Gas Flow ◽  
National Laboratory ◽  
Pyrolytic Carbon ◽  
Carbon Layer ◽  
High Concentration ◽  
Coated Particles ◽  
Oak Ridge ◽  
Coated Particle ◽  
Total Particle ◽  
Test Reactor

The next generation nuclear plant (NGNP)/advanced gas reactor (AGR) fuel development and qualification program includes a series of irradiation experiments in Idaho National Laboratory’s advanced test reactor. Tristructural isotropic (TRISO)-coated particles for the first AGR experiment, AGR-1, were produced at Oak Ridge National Laboratory (ORNL) in a 2-in.(5-cm)-diameter coater. A requirement of the NGNP/AGR program is to produce coated particles for later experiments in coaters more representative of industrial scale. Toward this end, tests have been performed by Babcock and Wilcox (Lynchburg, VA) in a 6-in.(15-cm)-diameter coater. These tests have led to successful fabrication of particles for the second AGR experiment, AGR-2. While a thorough study of how coating parameters affect particle properties was not the goal of these tests, the test data obtained provide insight into process parameter/coated particle property relationships. Most relationships for the 6-in.-diameter coater followed trends found with the ORNL 2-in. coater, in spite of differences in coater design and bed hydrodynamics. For example, the key coating parameters affecting pyrocarbon anisotropy were coater temperature, coating gas fraction, total gas flow rate, and kernel charge size. Anisotropy of the outer pyrolytic carbon layer also strongly correlates with coater differential pressure. In an effort to reduce the total particle fabrication run time, silicon carbide (SiC) was deposited with methyltrichlorosilane (MTS) concentrations up to 3 mol %. Using only hydrogen as the fluidizing gas, the high concentration MTS tests resulted in particles with lower than desired SiC densities. However, when hydrogen was partially replaced with argon, high SiC densities were achieved with the high MTS gas fraction.

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