Experimental Tests for Suppression Effects of Water Restraint Plates on Sloshing of a Water Pool

1988 ◽  
Vol 110 (3) ◽  
pp. 240-246 ◽  
Author(s):  
K. Muto ◽  
Y. Kasai ◽  
M. Nakahara

Forced vibration tests for a spent fuel storage pool of nuclear facilities [1] were conducted for the purpose of determining sloshing suppression effects. The devices reported in this paper are cantilever-type water restraint plates. They reduce sloshing and also prevent overflow of water from the pool. Parameters examined in the experimental tests were the installation height levels, lengths and shapes of the water restraint plates. The most effective installation conditions of these water restraint plates were found through the tests.

Author(s):  
Ronald Morris

DFD is an acronym for the “Decontamination for Decommissioning” process developed in 1996 by the Electric Power Research Institute (EPRI). The process was designed to remove radioactivity from the surfaces of metallic components to allow these components to be recycled or free-released for disposal as non-radioactive. DFD is a cyclic process consisting of fluoroboric acid, potassium permanganate and oxalic acid. The process continues to uniformly remove base metal once oxide dissolution is complete. The DFD process has been applied on numerous components, sub-systems and systems including the reactor systems at Big Rock Point and Maine Yankee in the United States, and the Jose Cabrera (Zorita) Nuclear Power Plant (NPP) in Spain. The Big Rock Point site has been returned to Greenfield and at Maine Yankee the land under the license was reduced for an Independent Spent Fuel Storage Installation (ISFSI). In the upcoming months the Zorita NPP in Spain will initiate dismantlement and decommissioning activities to return the site to a non-nuclear facility. The development of the EPRI DFD process has been an ongoing evolution and much has been learned from its use in the past. It is effective in attaining very high decontamination factors; however, DFD also produces secondary waste in the form of ion exchange resins. This secondary waste generation adds to the decommissioning quota but this can be improved upon at a time when radioactive waste storage at nuclear facilities and waste disposal sites is limited. To reduce the amount of secondary waste, EPRI has developed the DFDX process. This new process is an enhancement to the DFD process and produces a smaller amount of metallic waste rather than resin waste; this reduction in volume being a factor of ten or greater. Electrochemical ion exchange cells are the heart of the DFDX system and contain electrodes and cation ion exchange resin. It has been used very successfully in small system applications and the next evolution is to design, build and implement a system for the chemical decontamination for decommissioning of larger reactor systems and components, and Full System Decontamination (FSD). The purpose of this paper is to provide a reference point for those planning future chemical decontaminations for plant decommissioning. It is based on actual experience from the work already performed to date and the planned development of the DFDX process.


Author(s):  
Fouad Al-Musawi ◽  
Adnan Jarjies ◽  
Ross A. Miller

The Government of Iraq (GOI) has undertaken efforts to decommission and dismantle former nuclear facilities. The GOI has only preliminary information on some of the former nuclear facilities. This paper will highlight the challenges involved in conducting inspections of the outlying former nuclear facilities in Iraq and present a brief summary of the results of those inspections. The facilities discussed in this paper are located at various sites throughout Iraq, from locations close to Baghdad to those in the north and far western desert areas. Some of the facilities, such as those at the Al Tuwaitha Nuclear Research Center have been visited and characterized. Other facilities, including the following, have not been visited or thoroughly characterized. • Al Jesira, Uranium feed stock production facility; • Adaya, Burial location for contaminated equipment; • Djerf al Naddah, Spent fuel storage facility; • Rashdiya, Centrifuge development center; • Al Qa’im, Uranium (yellowcake) production facility. The visits were conducted to develop an inventory of the buildings/structures that need to be included in decommissioning/dismantlement efforts. The number of buildings, type of construction, size and general condition of the buildings were noted. In addition, attempts were made to determine contamination levels on surfaces, equipment, rubble, etc. This information will be used to support the Iraqi decommissioning and dismantlement project. Because the facilities are scattered throughout the country of Iraq, significant planning and coordination was required to ensure personnel security. Teams consisting of individuals from the Iraqi Ministry of Science and Technology (MoST) and Americans were under military escort when traveling to and visiting the sites. Because of the security issues, time on the ground at each site was limited. This paper will highlight the challenges involved in conducting the inspections of the outlying former nuclear facilities In Iraq and present a brief summary of the results of those inspections.


Author(s):  
Peter Nawrotzki

Power plant machinery can be dynamically decoupled from the substructure by the effective use of helical steel springs and viscous dampers. Turbine foundations, coal mills, boiler feed pumps and other machine foundations benefit from this type of elastic support systems to mitigate the transmission of operational vibration. The application of these devices may also be used to protect against earthquakes and other catastrophic events, i.e. airplane crash, of particular importance in nuclear facilities. This article illustrates basic principles of elastic support systems and applications on power plant equipment and buildings in medium and high seismic areas. Spring-damper combinations with special stiffness properties are used to reduce seismic acceleration levels of turbine components and other safety or non-safety related structures. For turbine buildings, the integration of the turbine substructure into the machine building can further reduce stress levels in all structural members. The application of this seismic protection strategy for a spent fuel storage tank in a high seismic area is also discussed. Safety in nuclear facilities is of particular importance and recent seismic events and the resulting damage in these facilities again brings up the discussion. One of the latest events is the 2007 Chuetsu earthquake in Japan. The resulting damage in the Kashiwazaki Kariwa Nuclear Power Plant can be found in several reports. Among other vital components, turbine equipment was damaged and overflow of fuel storage pools was observed (Fukushima, 2007 and Yamashita, 2008).


Author(s):  
Daogang Lu ◽  
Yu Liu ◽  
Shu Zheng

Free standing spent fuel storage racks are submerged in water contained with spent fuel pool. During a postulated earthquake, the water surrounding the racks is accelerated and the so-called fluid-structure interaction (FSI) is significantly induced between water, racks and the pool walls[1]. The added mass is an important input parameter for the dynamic structural analysis of the spent fuel storage rack under earthquake[2]. The spent fuel storage rack is different even for the same vendors. Some rack are designed as the honeycomb construction, others are designed as the end-tube-connection construction. Therefore, the added mass for those racks have to be measured for the new rack’s design. More importantly, the added mass is influenced by the layout of the rack in the spent fuel pool. In this paper, an experiment is carried out to measure the added mass by free vibration test. The measured fluid force of the rack is analyzed by Fourier analysis to derive its vibration frequency. The added mass is then evaluated by the vibration frequency in the air and water. Moreover, a two dimensional CFD model of the spent fuel rack immersed in the water tank is built. The fluid force is obtained by a transient analysis with the help of dynamics mesh method.


2006 ◽  
Vol 69 (2) ◽  
pp. 185-188 ◽  
Author(s):  
V. I. Kopeikin ◽  
L. A. Mikaelyan ◽  
V. V. Sinev

1980 ◽  
Vol 69 (3) ◽  
pp. 605-634 ◽  
Author(s):  
RT SEVERN ◽  
AP JEARY ◽  
BR ELLIS ◽  

1986 ◽  
Vol 137 (3) ◽  
pp. 190-202 ◽  
Author(s):  
M. Peehs ◽  
J. Fleisch

1989 ◽  
Vol 111 (4) ◽  
pp. 647-651 ◽  
Author(s):  
J. Y. Hwang ◽  
L. E. Efferding

A thermal analysis evaluation is presented of a nuclear spent fuel dry storage cask designed by the Westinghouse Nuclear Components Division. The cask is designed to provide passive cooling of 24 Pressurized Water Reactor (PWR) spent fuel assemblies for a storage period of at least 20 years at a nuclear utility site (Independent Spent Fuel Storage Installation). A comparison is presented between analytical predictions and experimental results for a demonstration cask built by Westinghouse and tested under a joint program with the Department of Energy and Virginia Power Company. Demonstration testing with nuclear spent fuel assemblies was performed on a cask configuration designed to store 24 intact spent fuel assemblies or canisters containing fuel consolidated from 48 assemblies.


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