Development of Shearing Device for Reducing the Storage Volume of the Spent Fuel Associated Assemblies in Nuclear Power Plants

Author(s):  
Zhang Bin ◽  
Qiao Su-kai ◽  
Hao Qing-jun ◽  
Huang Hong-zhi ◽  
Ding Ming ◽  
...  

With the continuous running of the nuclear power plants, a great deal of unavailable spent fuel associated assemblies were and will be produced in the aggregates of the nuclear power plants, which are usually stored in the spent fuel storage pool and occupy lots of spent fuel storage racks, making the spent fuel storage facility of the nuclear power plants face the risk of being filled up. Therefore, it drives the nuclear power plants to seek a new method to increase the spent fuel storage capacity. In order to increase the storage capacity of the spent fuel storage racks, a shearing device is proposed to shear the rods and base plates (or spider assemblies) of the spent fuel associated assemblies, reducing the storage volume of the spent fuel associated assemblies and reducing the amount of the occupied spent fuel storage racks. The technology of water-hydraulic shear is applied to carry the shear process through underwater cold extrusion, effectively ensuring the integrity of the rod structure and avoiding the pollution caused by radioactive substances. Besides, no swarf would be produced to pollute the spent fuel storage pool. Through the finite element calculation and confirmation on the spot, it is verified that the bearing requirement of the fixed blade (the key assembly unit) of the shearing device is met during the relevant disassembling process. Currently, the shearing device has been successfully applied to reducing the storage volume of the spent fuel associated assemblies in LingAo Nuclear Power Plant. Therefore, the shearing device is of certain promoting and reference value.

Author(s):  
You Shi ◽  
Dong Ning ◽  
Yi-zhong Yang

Boron Carbide (B4C) particle-reinforced aluminum matrix composite is the key material for use as neutron absorber plate in spent fuel storage racks as well as new fuel and in-containment fuel storage racks for GENIII advanced passive nuclear power plants in China. This material has once depended upon importing with high expense and restricted delivery schedule by foreign supplier. Therefore it has meaningful practical significance to realize the localized manufacturing for this material in China. More importantly, since it’s the first time for this material to be used in domestic plant, particular care should be taken to assure the formal supplied neutron absorber material products exhibit high stabilized and reliable service in domestic nuclear engineering. This paper initiates and proposes a principle design framework from technical view in qualification requirements for this neutron absorber material so as to guide the practical engineering application. Aiming at neutron absorber materials supplied under practical manufacturing condition in engineering delivery, the qualification requirements define B4C content, matrix chemistry, 10B isotope, bulk density, 10B areal density, mechanical property and microstructure as key criteria for material performance. The uniformity assessment as to different locations of this material is also required from at least three lots of material. Only qualified material meeting all of the qualification requirements should proceed to be verified by lifetime testing such as irradiation, corrosion and thermal aging testing. Systematic and comprehensive performance assessments and verification for process stabilization could be achieved through the above qualification. The long-term service for this neutron absorber material in reliable and safe way could be convincingly expected in spent fuel storage application in China.


2019 ◽  
Vol 5 (3) ◽  
Author(s):  
You Shi ◽  
Dong Ning ◽  
Yi-zhong Yang

Boron carbide (B4C) particle-reinforced aluminum matrix composite is the key material for use as neutron absorber plate in fuel storage applications for Generation III advanced passive nuclear power plants in China. This material has once depended upon importing with various restrictions so that it has meaningful practical significance to realize the localized manufacturing for this material in China. More importantly, since it is the first time for this material to be used in domestic plant, particular care should be taken to assure the formal supplied products exhibit high stabilized and reliable service in domestic nuclear engineering. This paper initiates and proposes a principle design framework from technical view in qualification requirements for this material so as to guide the practical engineering application. Aiming at neutron absorber materials supplied under practical manufacturing condition in engineering delivery, the qualification requirements define B4C content, matrix chemistry, 10B isotope, bulk density, 10B areal density, mechanical property, and microstructure as key criteria for material performance. The uniformity assessment as to different locations of this material is also required from at least three lots of material. Only qualified material meeting all of the qualification requirements should proceed to be verified by lifetime testing such as irradiation, corrosion, and thermal aging testing. Systematic and comprehensive performance assessments and verification for process stabilization could be achieved through the above qualification. The long-term service for this neutron absorber material in reliable and safe way could be convincingly expected in spent fuel storage application in China.


2014 ◽  
Vol 986-987 ◽  
pp. 589-592
Author(s):  
Xiang Zhen Han ◽  
Guo Shun You

Based on the Monte Carlo calculation method, geometric model of spent fuel storage pool Area I of small modular reactor is established, assuming infinite 6×6 type storage racks. Calculation results show that the reactivity is maximal when the water density is 1.0g/cm3. The value of keff is 0.8729 in normal storage condition. The spacing of storage racks in spent fuel pool would change in an earthquake accident condition. The values of reactivity of spent fuel pool in the assumed earthquake accident condition are also calculated. The values of keff are between 0.872 and 0.876. Both in normal condition and assumed earthquake accident condition, the values of keff are less than 0.95, to meet nuclear safety regulatory requirements.


2020 ◽  
pp. 62-71
Author(s):  
M. Sapon ◽  
O. Gorbachenko ◽  
S. Kondratyev ◽  
V. Krytskyy ◽  
V. Mayatsky ◽  
...  

According to regulatory requirements, when carrying out handling operations with spent nuclear fuel (SNF), prevention of damage to the spent fuel assemblies (SFA) and especially fuel elements shall be ensured. For this purpose, it is necessary to exclude the risk of SFA falling, SFA uncontrolled displacements, prevent mechanical influences on SFA, at which their damage is possible. Special requirements for handling equipment (in particular, cranes) to exclude these dangerous events, the requirements for equipment strength, resistance to external impacts, reliability, equipment design solutions, manufacturing quality are analyzed in this work. The requirements of Ukrainian and U.S. regulatory documents also are considered. The implementation of these requirements is considered on the example of handling equipment, in particular, spent nuclear fuel storage facilities. This issue is important in view of creation of new SNF storage facilities in Ukraine. These facilities include the storage facility (SFSF) for SNF from water moderated power reactors (WWER): a Сentralized SFSF for storing SNF of Rivne, Khmelnitsky and South-Ukraine Nuclear Power Plants (СSFSF), and SFSF for SNF from high-power channel reactors (RBMK): a dry type SFSF at Chornobyl nuclear power plant (ISF-2). After commissioning of these storage facilities, all spent nuclear fuel from Ukrainian nuclear power plants will be placed for long-term “dry” storage. The safety of handling operations with SNF during its preparation for long-term storage is an important factor.


10.6036/10156 ◽  
2021 ◽  
Vol 96 (4) ◽  
pp. 355-358
Author(s):  
Pablo Fernández Arias ◽  
DIEGO VERGARA RODRIGUEZ

Centralized Temporary Storage Facility (CTS) is an industrial facility designed to store spent fuel (SF) and high level radioactive waste (HLW) generated at Spanish nuclear power plants (NPP) in a single location. At the end of 2011, the Spanish Government approved the installation of the CTS in the municipality of Villar de Cañas in Cuenca. This approval was the outcome of a long process of technical studies and political decisions that were always surrounded by great social rejection. After years of confrontations between the different political levels, with hardly any progress in its construction, this infrastructure of national importance seems to have been definitively postponed. The present research analyzes the management strategy of SF and HLW in Spain, as well as the alternative strategies proposed, taking into account the current schedule foreseen for the closure of the Spanish NPPs. In view of the results obtained, it is difficult to affirm that the CTS will be available in 2028, with the possibility that its implementation may be delayed to 2032, or even that it may never happen, making it necessary to adopt an alternative strategy for the management of GC and ARAR in Spain. Among the different alternatives, the permanence of the current Individualized Temporary Stores (ITS) as a long-term storage strategy stands out, and even the possibility of building several distributed temporary storage facilities (DTS) in which to store the SF and HLW from several Spanish NPP. Keywords: nuclear waste, storage, nuclear power plants.


2021 ◽  
Author(s):  
Wen Yang ◽  
Xing Li ◽  
Jinrong Qiu ◽  
Lun Zhou

Abstract With the rapid development of nuclear energy, spent fuel will accumulate in large quantities. Spent fuel is generally cooled and placed in a storage pool, and then transported to a reprocessing plant at an appropriate time. Because spent fuel is content with a high level of radiation, spent fuel storage and transportation safety play important roles in the nuclear safety. Radiation dose safety are checked and validated using source analysis and Monte Carlo method to establish a radiation dose rate calculation model for PWR spent fuel storage pool and transport container. The calculation results show that the neutron and photon dose rates decrease exponentially with increase of water level under normal condition of storage pool. The attenuation multiples of neutron and photon dose rates are 4.64 and 1.59, respectively. According to radiation dose levels in different water height situations, spent fuel pool under loss of coolant accident can be divides into five workplaces. They are supervision zone, regular zone, intermittent zone, restricted zone and radiation zone. Under normal condition of transport container, the dose rates at the surface of the container and at a distance of 1 m from the surface are 0.1759 mSv/h and 0.0732 mSv/h, respectively. The dose rates decrease with the increasing radius of break accident, and dose rate at the surface of the transport container is 0.278 mSv/h when the break radius is 20 cm. Transport container conforms to the radiation safety standards of International Atomic Energy Agency (IAEA). This study can provide some reference for radiation safety analysis of spent fuel storage and transportation.


2021 ◽  
Vol 7 (1) ◽  
pp. 9-13
Author(s):  
David A. Hakobyan ◽  
Victor I. Slobodchuk

The problems of reprocessing and long-term storage of spent nuclear fuel (SNF) at nuclear power plants with RBMK reactors have not been fully resolved so far. For this reason, nuclear power plants are forced to search for new options for the disposal of spent fuel, which can provide at least temporary SNF storage. One of the possible solutions to this problem is to switch to compacted SNF storage in reactor spent fuel pools (SFPs). As the number of spent fuel assemblies (SFAs) in SFPs increases, a greater amount of heat is released. In addition, no less important is the fact that a place for emergency FA discharging should be provided in SFPs. The paper presents the results of a numerical simulation of the temperature conditions in SFPs both for compacted SNF storage and for emergency FA discharging. Several types of disturbances in normal SFP cooling mode are considered, including partial loss of cooling water and exposure of SFAs. The simulation was performed using the ANSYS CFX software tool. Estimates were made of the time for heating water to the boiling point, as well as the time for heating the cladding of the fuel elements to a temperature of 650 °С. The most critical conditions are observed in the emergency FA discharging compartment. The results obtained make it possible to estimate the time that the personnel have to restore normal cooling mode of the spent fuel pool until the maximum temperature for water and spent fuel assemblies is reached.


Author(s):  
Liming Huang ◽  
Shouhai Yang ◽  
Jie Liu

Radiation safety is an important part of safety assessment of spent fuel dry storage technology. This paper describes the radiation protection design of PWR spent fuel dry storage facility for radiation safety completed by China General Nuclear Power Corporation. Considering the special site conditions, Monte Carlo method is used to complete the precise calculation of the three-dimensional radiation dose field in the spent fuel storage building. Through the spent fuel storage module and the storage building with shielding function, radiation shielding design is completed to meet China’s regulatory requirements, which ensures radiation safety for workers and the public during the transport and storage of spent fuel. It will provide a reference for construction of spent fuel dry storage facility of CPR1000 and HPR1000.


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