Yulong Li, Feng Liu, Xiajie Liu, L. Li, Z. Kang, Ye He
Excessive gamma rays will be emitted when a nuclear power plant is under the overhauling, leading to a certain number of hotspots. To meet the shielding requirements of these hotspots, a new type of flexible shielding materials with a “sandwich structure” has been developed. New flexible shielding materials consist of two parts, one is silicone rubber with excellent physical and chemical properties by adding reasonable multi-component additives as matrix, and the other is lead powder as shielding body. This kind of material with lead powder dispersed uniformly in silicone rubber was prepared through mixing process. Based on this, the article has carried on the discussion to the performance of functional layer of the new flexible shielding materials. The problem that the process stability of ultrafine powder distributed uniformly in matrix with various densities among different regions has been solved as well. Furthermore, this kind of material has been adopted in CPR nuclear power plant as the first demonstration project. The site shielding effect has been recognized by WANO (world association of nuclear operators). As a result of this research, it is possible that the scheme of radiation shield for a short or long time can be make quickly when nuclear power plant running or overhauling. Meanwhile, this study is of great significance for the popularization and application of shielding materials.
{"title":"Study on Performance of New Flexible Shielding Materials and First Demonstration Application in CPR Nuclear Power Plant","authors":"Yulong Li, Feng Liu, Xiajie Liu, L. Li, Z. Kang, Ye He","doi":"10.1115/icone29-91566","DOIUrl":"https://doi.org/10.1115/icone29-91566","url":null,"abstract":"\u0000 Excessive gamma rays will be emitted when a nuclear power plant is under the overhauling, leading to a certain number of hotspots. To meet the shielding requirements of these hotspots, a new type of flexible shielding materials with a “sandwich structure” has been developed. New flexible shielding materials consist of two parts, one is silicone rubber with excellent physical and chemical properties by adding reasonable multi-component additives as matrix, and the other is lead powder as shielding body. This kind of material with lead powder dispersed uniformly in silicone rubber was prepared through mixing process. Based on this, the article has carried on the discussion to the performance of functional layer of the new flexible shielding materials. The problem that the process stability of ultrafine powder distributed uniformly in matrix with various densities among different regions has been solved as well. Furthermore, this kind of material has been adopted in CPR nuclear power plant as the first demonstration project. The site shielding effect has been recognized by WANO (world association of nuclear operators). As a result of this research, it is possible that the scheme of radiation shield for a short or long time can be make quickly when nuclear power plant running or overhauling. Meanwhile, this study is of great significance for the popularization and application of shielding materials.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114676194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The complete life of a nuclear power plant consists of three stages: construction, operation and decommissioning. In the last stage of the operation life of nuclear power plants, they have to face the problem of decommissioning. The safe decommissioning of nuclear power plants is the guarantee for the sustainable development of nuclear power. After the termination of the operation of nuclear power plants, in order to ensure the safety of the public and the environment, the plant site should be purified, demolished and cleaned to reach the restricted utilization level or unrestricted opening. This paper studies the operation and decommissioning status of nuclear power plants from both international and domestic levels, and analyzes the real time cycle and development trend of decommissioning projects. The research shows that in the international nuclear power plant decommissioning market, the nuclear power pioneer countries have successively established national laboratories or research centers to carry out research on the decommissioning technology of nuclear power plants, developed a large number of advanced technologies and tooling equipment, and formed their own technical characteristics and technical advantages; the nuclear power plant decommissioning is increasingly researched in China, but the decommissioning practice has not been started yet in this country. The industry and relevant parties should carry out systematic construction for the decommissioning of nuclear power plants from the aspects of capital sources, regulations, standards, technical reserves, organizational structure and talent reserves.
{"title":"Current Situation and Development Trend of Decommissioning of Nuclear Power Plants","authors":"Cao Guochang, Kang Yunding, Li Zhihua","doi":"10.1115/icone29-93254","DOIUrl":"https://doi.org/10.1115/icone29-93254","url":null,"abstract":"\u0000 The complete life of a nuclear power plant consists of three stages: construction, operation and decommissioning. In the last stage of the operation life of nuclear power plants, they have to face the problem of decommissioning. The safe decommissioning of nuclear power plants is the guarantee for the sustainable development of nuclear power. After the termination of the operation of nuclear power plants, in order to ensure the safety of the public and the environment, the plant site should be purified, demolished and cleaned to reach the restricted utilization level or unrestricted opening. This paper studies the operation and decommissioning status of nuclear power plants from both international and domestic levels, and analyzes the real time cycle and development trend of decommissioning projects. The research shows that in the international nuclear power plant decommissioning market, the nuclear power pioneer countries have successively established national laboratories or research centers to carry out research on the decommissioning technology of nuclear power plants, developed a large number of advanced technologies and tooling equipment, and formed their own technical characteristics and technical advantages; the nuclear power plant decommissioning is increasingly researched in China, but the decommissioning practice has not been started yet in this country. The industry and relevant parties should carry out systematic construction for the decommissioning of nuclear power plants from the aspects of capital sources, regulations, standards, technical reserves, organizational structure and talent reserves.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131305332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
All Structures, Systems, and Components (SSCs) in a nuclear power plant need to be classified according to their importance to safety to protect people and the environment. The Specific Safety Guide, No. SSG-30, issued by IAEA, guides how to meet the requirements for identifying safety functions and classification of SSCs and ensuring their appropriate quality and reliability. However, the relevant guidance has not specified the perspectives of low radiological consequences on on-site workers. To refine the SSCs classification and complement the IAEA guidance, a proposed limiting value and corresponding assessment method for low radiological consequence caused by SSCs failure from the on-site workers’ perspective based on international good practices are developed, which include the main process of on-site radiological consequence evaluation, the calculation method for different exposure pathways and the assessment assumptions. Also, typical examples of SSCs failure are also assessed to validate the proposed method’s feasibility. The assessment results show that the activity concentration of failure SSCs, the workers’ locations, the exposure duration of workers, and the local dose rate of each location are the main factors for on-site radiological consequence evaluation, and the proposed method in this paper can assist in the safety classification of SSCs in the third generation of pressurized water reactor nuclear power plants.
{"title":"Assessment and Control Value Formulation on Radiological Consequence of On-Site Worker due to Radioactive Component Failure for Pressurized Water Reactor Plant","authors":"Zhou Jing, Ran Wen Wang, Gong Quan, Lv Wei Feng","doi":"10.1115/icone29-91624","DOIUrl":"https://doi.org/10.1115/icone29-91624","url":null,"abstract":"\u0000 All Structures, Systems, and Components (SSCs) in a nuclear power plant need to be classified according to their importance to safety to protect people and the environment. The Specific Safety Guide, No. SSG-30, issued by IAEA, guides how to meet the requirements for identifying safety functions and classification of SSCs and ensuring their appropriate quality and reliability. However, the relevant guidance has not specified the perspectives of low radiological consequences on on-site workers. To refine the SSCs classification and complement the IAEA guidance, a proposed limiting value and corresponding assessment method for low radiological consequence caused by SSCs failure from the on-site workers’ perspective based on international good practices are developed, which include the main process of on-site radiological consequence evaluation, the calculation method for different exposure pathways and the assessment assumptions. Also, typical examples of SSCs failure are also assessed to validate the proposed method’s feasibility. The assessment results show that the activity concentration of failure SSCs, the workers’ locations, the exposure duration of workers, and the local dose rate of each location are the main factors for on-site radiological consequence evaluation, and the proposed method in this paper can assist in the safety classification of SSCs in the third generation of pressurized water reactor nuclear power plants.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128923250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liu Qiaofen, Huo Ming, Gao Fei, Yang Linjun, Liu Yong
Evaporation method has been widely used in radioactivity wastewater treatment of nuclear power plants because of its high decontamination factor (DF) and wide application range of water quality. However, the traditional evaporation system has high energy consumption. Aiming at the recovery of latent heat of secondary steam during stable evaporation of wastewater in radioactivity, a new evaporation system & mechanical vapor recompression (MVR) was proposed and studied. Firstly, a mathematical model is established according to the conservation equations of mass and energy. The factors affecting energy consumption, decontamination factors, and secondary waste that needing attention due to radioactivity are discussed. According to the improved scheme, a prototype was built and the wastewater treatment experiment in simulated radioactive water was carried out. The actual energy saving rate and decontamination factor are calculated and analyzed. The results show that, at the conditions of evaporation rate of 600kg/h and evaporation temperature of 100°C, compared with traditional evaporation, MVR can save 84.8%energy, and the decontamination factor (DF) reaches 105 in simulated waste liquid treatment experiment. MVR shows that this method has obvious advantages in economic and environmental benefits.
{"title":"Mechanical Vapor Re-Compression Evaporation Treatment of Radioactive Waste Water","authors":"Liu Qiaofen, Huo Ming, Gao Fei, Yang Linjun, Liu Yong","doi":"10.1115/icone29-91897","DOIUrl":"https://doi.org/10.1115/icone29-91897","url":null,"abstract":"\u0000 Evaporation method has been widely used in radioactivity wastewater treatment of nuclear power plants because of its high decontamination factor (DF) and wide application range of water quality. However, the traditional evaporation system has high energy consumption. Aiming at the recovery of latent heat of secondary steam during stable evaporation of wastewater in radioactivity, a new evaporation system & mechanical vapor recompression (MVR) was proposed and studied. Firstly, a mathematical model is established according to the conservation equations of mass and energy. The factors affecting energy consumption, decontamination factors, and secondary waste that needing attention due to radioactivity are discussed. According to the improved scheme, a prototype was built and the wastewater treatment experiment in simulated radioactive water was carried out. The actual energy saving rate and decontamination factor are calculated and analyzed. The results show that, at the conditions of evaporation rate of 600kg/h and evaporation temperature of 100°C, compared with traditional evaporation, MVR can save 84.8%energy, and the decontamination factor (DF) reaches 105 in simulated waste liquid treatment experiment. MVR shows that this method has obvious advantages in economic and environmental benefits.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133209680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cs2LiLaBr6:Ce (CLLB) scintillation detector has excellent energy resolution and high light output to gamma-rays, with excellent neutron/gamma-rays discrimination performance. Its applications are mainly limited to crystal growth with large size and high quality. In this paper, high performance CLLB was grown, encapsulated and tested. The vertical Bridgman method was employed to grow Cs2LiLaBr6:1%Ce crystals. By regulating the temperature, the maximum temperature gradient of the growth furnace was adjusted to the position of crystal precipitation. To avoid the non-uniform melting component area, the non-stoichiometric of raw materials increasing the excess of 100% LiBr were used. The crystals was developed successfully with 1 inch diameter, 5 cm length, and 4.32 g/mL density. Finally, the crystal was encapsulated and tested, with an energy resolution of 4.0% and relative (NaI) optical output of 1.14 to 0.662 MeV gamma-rays, and an absolute optical output of 47665 Photons/MeV to 0.511 MeV gamma-rays; The figure of merit (FOM) of the neutron/gamma-rays discrimination is 1.27 enabled by charge comparison method. The scintillation decay time of the two kinds of signals is measured respectively by the optical flux simulation method, with a fast component of about 0.19 μs and a slow component of 1.08 μs. Results show that the neutron signals has a higher fast component proportion to gamma-rays signals.
{"title":"Study on the Growth and Scintillation Properties of CLLB Crystals","authors":"Kun Wu, Leilei Zhang, Haijun Li, Guangwei Huang, Jiaming Li, Libin Wang, Siyuan Zhang, Zhiyuan Li, Qinhua Wei, Chunzhi Zhou, Zungang Wang, Huilan Liu, Hongying Zhu, Yushou Song","doi":"10.1115/icone29-91215","DOIUrl":"https://doi.org/10.1115/icone29-91215","url":null,"abstract":"\u0000 Cs2LiLaBr6:Ce (CLLB) scintillation detector has excellent energy resolution and high light output to gamma-rays, with excellent neutron/gamma-rays discrimination performance. Its applications are mainly limited to crystal growth with large size and high quality. In this paper, high performance CLLB was grown, encapsulated and tested. The vertical Bridgman method was employed to grow Cs2LiLaBr6:1%Ce crystals. By regulating the temperature, the maximum temperature gradient of the growth furnace was adjusted to the position of crystal precipitation. To avoid the non-uniform melting component area, the non-stoichiometric of raw materials increasing the excess of 100% LiBr were used. The crystals was developed successfully with 1 inch diameter, 5 cm length, and 4.32 g/mL density. Finally, the crystal was encapsulated and tested, with an energy resolution of 4.0% and relative (NaI) optical output of 1.14 to 0.662 MeV gamma-rays, and an absolute optical output of 47665 Photons/MeV to 0.511 MeV gamma-rays; The figure of merit (FOM) of the neutron/gamma-rays discrimination is 1.27 enabled by charge comparison method. The scintillation decay time of the two kinds of signals is measured respectively by the optical flux simulation method, with a fast component of about 0.19 μs and a slow component of 1.08 μs. Results show that the neutron signals has a higher fast component proportion to gamma-rays signals.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126812889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flexible and accurate estimation of dose absorbed by critical human organs is important to ensure and improve workers’ radiation safety. Absorbed doses for different organs and tissues are affected by their positions and the orientation of the body in the radiation field. This paper presents a skeletal animated local method of characteristic (SALMOC) dose assessment method that considers the working dynamics and organ-level dose for occupational workers during nuclear facility decommissioning. The proposed method combines the verisimilitude of skeletal animation technology (SA) with the flexibility of the local method of characteristics (LMOC). To account for the working posture, the change in different working postures are controlled by skeletal animation, and then the voxel model in a certain pose is generated according to the changed human model. Finally, the LMOC is used to perform the dose assessment. The proposed SALMOC method not only accounts for different working postures during the decommissioning of nuclear facilities but also considers the occlusion and scattering effect of the human model to achieve accurate organ-level dose assessment. The effectiveness of the proposed method is verified by comparing the results with those derived from the Monte-Carlo method and Point-Kernel method evaluated on two different organs. The result shows that the proposed method can generate voxel models for irregular organs, and the tests show better consistency with the Monte-Carlo method compared with the Point-Kernel method.
{"title":"The Dose Assessment Method Based on the Local Method of Characteristics and Skeletal Animation","authors":"Lun-xiu Cao, Nan Chao, Yong-kuo Liu, Zhi-tao Chen","doi":"10.1115/icone29-92195","DOIUrl":"https://doi.org/10.1115/icone29-92195","url":null,"abstract":"\u0000 Flexible and accurate estimation of dose absorbed by critical human organs is important to ensure and improve workers’ radiation safety. Absorbed doses for different organs and tissues are affected by their positions and the orientation of the body in the radiation field. This paper presents a skeletal animated local method of characteristic (SALMOC) dose assessment method that considers the working dynamics and organ-level dose for occupational workers during nuclear facility decommissioning. The proposed method combines the verisimilitude of skeletal animation technology (SA) with the flexibility of the local method of characteristics (LMOC). To account for the working posture, the change in different working postures are controlled by skeletal animation, and then the voxel model in a certain pose is generated according to the changed human model. Finally, the LMOC is used to perform the dose assessment. The proposed SALMOC method not only accounts for different working postures during the decommissioning of nuclear facilities but also considers the occlusion and scattering effect of the human model to achieve accurate organ-level dose assessment. The effectiveness of the proposed method is verified by comparing the results with those derived from the Monte-Carlo method and Point-Kernel method evaluated on two different organs. The result shows that the proposed method can generate voxel models for irregular organs, and the tests show better consistency with the Monte-Carlo method compared with the Point-Kernel method.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115447092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hui Yang, Hao Zhou, Bing-feng Dong, Wentao Zhou, W. Gu, Xinyu Zhang, Qin Lei, Chenyu Shan, Dezhong Wang
The accuracy of tomographic gamma scanning transmission reconstruction is a critical factor in reconstructing the activity of a radioactive drum. Traditional reconstruction algorithms produce severe grid artifacts and a high level of noise, thereby increasing the reconstruction error for both the density map and the activity. This paper proposes a novel algorithm for transmission reconstruction by combining maximum-likelihood expectation maximization and a convolutional neural network (CNN). Our experimental results indicate that the proposed reconstruction algorithm is capable of significantly reducing measurement errors, increasing spatial resolution while also eliminating grid artifacts, and being sufficiently robust when dealing with a noisy input image. The mean squared error of the output image decreased by 52.70% compared with the conventional reconstruction method, and the peak signal-to-noise ratio and structural similarity index improved by 21.89% and 17.33%, respectively. The spatial resolution was improved by 28 times, which demonstrates that CNN is a potentially useful new method for radioactive waste drum transmission image reconstruction.
{"title":"A Novel Transmission Reconstruction Algorithm for Radioactive Drum Characterization","authors":"Hui Yang, Hao Zhou, Bing-feng Dong, Wentao Zhou, W. Gu, Xinyu Zhang, Qin Lei, Chenyu Shan, Dezhong Wang","doi":"10.1115/icone29-90126","DOIUrl":"https://doi.org/10.1115/icone29-90126","url":null,"abstract":"\u0000 The accuracy of tomographic gamma scanning transmission reconstruction is a critical factor in reconstructing the activity of a radioactive drum. Traditional reconstruction algorithms produce severe grid artifacts and a high level of noise, thereby increasing the reconstruction error for both the density map and the activity. This paper proposes a novel algorithm for transmission reconstruction by combining maximum-likelihood expectation maximization and a convolutional neural network (CNN). Our experimental results indicate that the proposed reconstruction algorithm is capable of significantly reducing measurement errors, increasing spatial resolution while also eliminating grid artifacts, and being sufficiently robust when dealing with a noisy input image. The mean squared error of the output image decreased by 52.70% compared with the conventional reconstruction method, and the peak signal-to-noise ratio and structural similarity index improved by 21.89% and 17.33%, respectively. The spatial resolution was improved by 28 times, which demonstrates that CNN is a potentially useful new method for radioactive waste drum transmission image reconstruction.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114598316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kai Tao, Liming Huang, Yadong Ding, Zhenhai Zou, D. E
The electron beam dump for Dalian Advanced Light Source (DALS) is designed to absorb 15 kW of electron beam power at beam energy up to 120 MeV. The DALS accelerator produces an electron beam with very small beam size of up to 100 μA average current. The resulting beam power, up to 15 kW at 120 MeV, and the very high beam power density, pose challenging problems for beam dump design. High power dump with water cooled has been developed for DALS. In the dump, most of the beam power is finally absorbed in water and taken out from the dump. The core of the high power electron beam dump is designed to be constructed from an aluminum alloy using a cylindrical geometry with fins arranged around to promote the heat transfer. The cooling water is forced by a cooling pump, to cool the core of the dump through the cooling channels. The beam is stopped in the dump involving a high production of neutron and gamma radiation and activation of its surface. A shield has been designed to attenuate both the radiation produced during accelerator operation and the residual radiation. Design details for the dump, including radiation shielding calculations, thermal analysis are presented.
{"title":"High Power Electron Beam Dump at DALS","authors":"Kai Tao, Liming Huang, Yadong Ding, Zhenhai Zou, D. E","doi":"10.1115/icone29-91515","DOIUrl":"https://doi.org/10.1115/icone29-91515","url":null,"abstract":"\u0000 The electron beam dump for Dalian Advanced Light Source (DALS) is designed to absorb 15 kW of electron beam power at beam energy up to 120 MeV. The DALS accelerator produces an electron beam with very small beam size of up to 100 μA average current. The resulting beam power, up to 15 kW at 120 MeV, and the very high beam power density, pose challenging problems for beam dump design.\u0000 High power dump with water cooled has been developed for DALS. In the dump, most of the beam power is finally absorbed in water and taken out from the dump.\u0000 The core of the high power electron beam dump is designed to be constructed from an aluminum alloy using a cylindrical geometry with fins arranged around to promote the heat transfer. The cooling water is forced by a cooling pump, to cool the core of the dump through the cooling channels.\u0000 The beam is stopped in the dump involving a high production of neutron and gamma radiation and activation of its surface. A shield has been designed to attenuate both the radiation produced during accelerator operation and the residual radiation.\u0000 Design details for the dump, including radiation shielding calculations, thermal analysis are presented.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128231960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Basically, decommissioning of nuclear facilities is a project that does not generate new profit because it is carried out with the reserve funds from operation, etc. Therefore, its cost should be minimized with optimization by shortening the process and minimizing the waste, etc. Meeting the requirements of exposure risk (safety) also affects the optimization. In this study, we decided to integrate these evaluation methods to develop a comprehensive optimization evaluation method. In this study, we established an average process for the current decommissioning plans of Japanese nuclear power plants and developed a cost evaluation method including sensitivity analysis. As a result of examining the feasibility of the deferred dismantling strategy using the above calculation method, it became clear that although there is a reduction in disposal and dismantling costs due to the natural decay of radioactive materials, the maintenance and management costs during the safe storage period account for a large proportion of the costs, and for this reason, immediate dismantling is unconditionally advantageous, at least in Japan. The components of optimization described above are naturally subject to various uncertainties and risks. For example, there are regulatory risks, and the location of waste disposal site is subject to social acceptance, so there is a great deal of uncertainty. In the future, these factors will be incorporated into the evaluation and studied, and the optimal strategy for decommissioning and what kind of uncertainty should be focused on will be clarified quantitatively.
{"title":"Study for the Optimization of the Decommissioning Project of Nuclear Facilities","authors":"Y. Iguchi, D. Kawasaki, S. Yanagihara","doi":"10.1115/icone29-88888","DOIUrl":"https://doi.org/10.1115/icone29-88888","url":null,"abstract":"\u0000 Basically, decommissioning of nuclear facilities is a project that does not generate new profit because it is carried out with the reserve funds from operation, etc. Therefore, its cost should be minimized with optimization by shortening the process and minimizing the waste, etc. Meeting the requirements of exposure risk (safety) also affects the optimization. In this study, we decided to integrate these evaluation methods to develop a comprehensive optimization evaluation method.\u0000 In this study, we established an average process for the current decommissioning plans of Japanese nuclear power plants and developed a cost evaluation method including sensitivity analysis.\u0000 As a result of examining the feasibility of the deferred dismantling strategy using the above calculation method, it became clear that although there is a reduction in disposal and dismantling costs due to the natural decay of radioactive materials, the maintenance and management costs during the safe storage period account for a large proportion of the costs, and for this reason, immediate dismantling is unconditionally advantageous, at least in Japan.\u0000 The components of optimization described above are naturally subject to various uncertainties and risks. For example, there are regulatory risks, and the location of waste disposal site is subject to social acceptance, so there is a great deal of uncertainty. In the future, these factors will be incorporated into the evaluation and studied, and the optimal strategy for decommissioning and what kind of uncertainty should be focused on will be clarified quantitatively.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128557454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the special nature of the radiation sources involved (high radioactivity and high penetration) in high discharge waste treatment facilities, several shielding doors are installed in the facilities to ensure staff safety. In the analysis of the radiation protection design of shielding doors, it is found that the type of radiation source, the relative position of the radiation source and the door, and the structure of the door all have an impact on the radiation shielding effect. In this paper, the shielding door of a hot room in a high discharge waste treatment facility is used as the research object, and the dose rate outside the shielding door is analyzed with the characteristics of radiation sources and their different locations, and with respect to the existing shielding door structure. The analysis results show that, under the premise of meeting the shielding requirements, when the radiation emitted by the source has a certain angle of incidence relative to the shielding door, the dose rate at a specific location outside the door will be significantly increased due to the scattering leakage of the door slit and the effect of the oblique penetration of the radiation. In addition, the characteristics of the radiation source, such as the type of nuclide, and the geometry can also influence the safety design of the shielded door. Therefore, in order to optimize the protection effect of shielded doors, considering that the characteristics of radiation sources are generally difficult to optimize, this paper proposes several solutions from two perspectives: door slit scattering and overlap length, and combining other influencing factors from different aspects. The optimization effects of each solution are also compared, and the corresponding adaptation sites are also outlined through their respective advantages and disadvantages. Through the analysis and research of this paper, the safety and effectiveness of the shielding door is improved, the safety of personnel is guaranteed, and the foundation for the future design of the shield door is laid.
{"title":"Discussion on Optimization of Protection Effect of Shielding Doors in High Level Waste Treatment Facilities","authors":"Jingyi Shen, Liying Zhang, Bingheng Wang, Guiling Gao","doi":"10.1115/icone29-88931","DOIUrl":"https://doi.org/10.1115/icone29-88931","url":null,"abstract":"\u0000 Due to the special nature of the radiation sources involved (high radioactivity and high penetration) in high discharge waste treatment facilities, several shielding doors are installed in the facilities to ensure staff safety. In the analysis of the radiation protection design of shielding doors, it is found that the type of radiation source, the relative position of the radiation source and the door, and the structure of the door all have an impact on the radiation shielding effect. In this paper, the shielding door of a hot room in a high discharge waste treatment facility is used as the research object, and the dose rate outside the shielding door is analyzed with the characteristics of radiation sources and their different locations, and with respect to the existing shielding door structure. The analysis results show that, under the premise of meeting the shielding requirements, when the radiation emitted by the source has a certain angle of incidence relative to the shielding door, the dose rate at a specific location outside the door will be significantly increased due to the scattering leakage of the door slit and the effect of the oblique penetration of the radiation. In addition, the characteristics of the radiation source, such as the type of nuclide, and the geometry can also influence the safety design of the shielded door. Therefore, in order to optimize the protection effect of shielded doors, considering that the characteristics of radiation sources are generally difficult to optimize, this paper proposes several solutions from two perspectives: door slit scattering and overlap length, and combining other influencing factors from different aspects. The optimization effects of each solution are also compared, and the corresponding adaptation sites are also outlined through their respective advantages and disadvantages. Through the analysis and research of this paper, the safety and effectiveness of the shielding door is improved, the safety of personnel is guaranteed, and the foundation for the future design of the shield door is laid.","PeriodicalId":249213,"journal":{"name":"Volume 9: Decontamination and Decommissioning, Radiation Protection, and Waste Management","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122223798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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