Research on diagnosis of fuel defects in operating pressurized water reactors
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摘要: 燃料棒是核电厂包容放射性物质的第一道屏障。燃料棒破损会导致冷却剂裂变产物活度升高,严重时机组须在数小时内后撤到停堆。通过取样监测的冷却剂放射化学数据可以一定程度上反映堆芯内装载燃料棒的破损情况。本研究介绍了压水堆核电厂功率运行期间冷却剂内裂变产物的来源,分析了裂变产物通过反冲和扩散方式的产生机理,通过求解迁移方程得到稳态情况下裂变产物活度的解析解。基于最小二乘法对反冲释放和扩散释放的裂变产物释放产生比进行解谱,建立了诊断压水堆燃料棒破损时间、破口程度、锕系核素泄漏、燃耗和燃料批次的定量分析模型。采用某百万千瓦压水堆运行中发生二次氢化的燃料循环的冷却剂裂变产物监测数据进行了验证,理论模型的分析结果也与机组停堆后啜漏检查和热室检查结果相符。Abstract: Fuel cladding is the first barrier to confine the radionuclides produced in the reactor core. Once the fuel rods defect, fission product activity in the primary loops will increase and may lead to temporary shutdown of the reactor when fuel rod failure has deteriorated to certain levels. This paper introduces the theoretical mechanism of production and migration of fission product from defective fuel rods to the primary loops in the operating pressurized water reactors. The analytical solution of fission product concentration in primary loops is got based on the first-order differential equations for steady operation. Based on the release-to-birth ratios for recoil and diffusion by least squares method, a method is developed to diagnose the status of fuel failure in pressurized water reactors, including fuel failure time, the degrees of defect size, the disseminated actinides, the average burnup and the fuel batch. The prediction results of fuel failure are verified well with that of a typical fuel failure with secondary degradation in one commercial pressurized water reactor, as well as those of the sipping test and the post irradiation examination.
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Key words:
- fuel failure /
- fission product /
- release-to-birth /
- secondary hydriding
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表 1 泄漏重核对冷却剂138Xe和134I活度的贡献
Table 1. Contribution of released actinides to the measured 138Xe and 134I activities
run time/d contribution to 138Xe activity/% contribution to 134I activity/% 15 0 0 30 16 17 124 71 52 215 77 77 308 86 93 -
[1] Beninson D, Matsuura S, Birkhofer A, et al. Defence in depth in nuclear safety – A report by the international nuclear safety advisory group[R]. Vienna: International Atomic Energy Agency, 1996. [2] Aqrawi A, Bertran de Balanda E, Bonnet E R, et al. Quality and reliability aspects in nuclear power reactor fuel engineering[R]. Vienna: International Atomic Energy Agency, 2015. [3] Bibilashvili Yu K, Dangouèmce D, Ichikawa, M, et al. Review of fuel failures in water cooled reactors[R]. Vienna: International Atomic Energy Agency, 1998. [4] Belzic J L, Tigeras A, Florence D. Surveillance strategies for primary coolant activity in operation PWR plants international comparison[C]//Proceedings of the International Conference on Water Chemistry in Nuclear Reactors Systems—Operation Optimisation and New Developments. 2002. [5] Chapot J L C, Suano R, do Couto N. Fuel failures at Angra 1: cause and mitigation[C]//Proceedings of Fuel Failure in Water Reactors: Cause and Mitigation. 2003: 92-116. [6] Chapot J, Freire J. Tracing fuel failures at Angra 1[J]. Nuclear Engineering International, 1994, 39(482): 32-34. [7] Halter A. IRSN assessment of fuel rods failures due to fretting phenomenon cycle 8 of Cattenom 3 Unit[C]//Proceedings of the International Symposium - The Eurosafe Forum 2003: Nuclear Expertise and Challenges of the Enlargement of the European Union. 2003. [8] Alvarez L, Daniels T, Dangoulème D, et al. Review of fuel failures in water cooled reactors[R]. Vienna: International Atomic Energy Agency, 2010. [9] Tarasov V, Ozrin V D, Veshchunov M S. Fuel failure in normal operation of water reactors: experience, causes and mitigation[R]. Vienna: International Atomic Energy Agency, 2022. [10] 肖岷. 压水堆核电站燃料管理、燃料制造与燃料运行[M]. 北京: 原子能出版社, 2009: 294-315Xiao Min. Fuel management, manufacture and operation for pressurized water reactor nuclear power plant[M]. Beijing: Atomic Energy Press, 2009: 294-315 [11] Leuthrot C, Beslu P. Distribution of actinides and solid fission products inside PWR primary circuits[C]//Proceedings of the International Conference on Water Chemistry of Nuclear Reactor Systems 4. 1986: 183-187. [12] Benfarah M, Dinse C, Sornein M O, et al. Behavior of disseminated actinides in PWR primary coolant[C]//Proceedings of the LWR Fuel Performance Meeting. 2013: 8323-8327. [13] Genin J B, Lamontagne J, Excoffier E, et al. Fissile material contamination behavior in PWR primary circuit[C]//Proceedings of the Nuclear Plant Chemistry Conference. 2006: 1-6. [14] Lewis B J. Fission product release from nuclear fuel by recoil and knockout[J]. Journal of Nuclear Materials, 1987, 148(1): 28-42. doi: 10.1016/0022-3115(87)90515-0 [15] Lewis B J. Fundamental aspects of defective nuclear fuel behaviour and fission product release[J]. Journal of Nuclear Materials, 1988, 160(2/3): 201-217. [16] Lewis B J, Phillips C R, Notley M J F. A model for the release of radioactive krypton, xenon, and iodine from defective UO2 fuel elements[J]. Nuclear Technology, 1986, 73(1): 72-83. doi: 10.13182/NT86-A16203 [17] Lewis B J, MacDonald R D, Ivanoff N V, et al. Fuel performance and fission product release studies for defected fuel elements[J]. Nuclear Technology, 1993, 103(2): 220-245. doi: 10.13182/NT93-A34845 [18] Beslu P, Leuthrot C, Frejaville G. PROFIP code: a model to evaluate the release of fission product from a defective fuel in PWR[C]//Proceedings of the IAEA Meeting on the Behaviour of Defected Zirconium Alloys Clad Ceramic Fuel in Water Coolant Reactors. 1979. [19] 景福庭, 陈炳德, 杨洪润, 等. 放射性裂变产物由燃料芯块释放到一回路的影响因素研究[J]. 核动力工程, 2013, 34(2):79-82 doi: 10.3969/j.issn.0258-0926.2013.02.018Jing Futing, Chen Bingde, Yang Hongrun, et al. Analysis of effects on radioactive fission product release from fuel pellet to coolant[J]. Nuclear Power Engineering, 2013, 34(2): 79-82 doi: 10.3969/j.issn.0258-0926.2013.02.018 [20] Chun M H, Tak N I, Lee S K. Development of a computer code to estimate the fuel rod failure using primary coolant activities of operating PWRS[J]. Annals of Nuclear Energy, 1998, 25(10): 753-763. doi: 10.1016/S0306-4549(97)00126-6 [21] Fu Pengtao. Determination of escape rate coefficients of fission products from the defective fuel rod with large defects in PWR[J]. Nuclear Engineering and Technology, 2023, 55(8): 2977-2983. doi: 10.1016/j.net.2023.05.001 [22] Tigeras A, Ambard A, Laugier F, et al. MERLIN: modelling fuel defects at EDF power plants[C]//Proceedings of the International Conference on Water Chemistry of Nuclear Reactor Systems. 2004: 1967-1977. [23] Menendez M A T. Fuel failure detection, characterization and modelling: effect on radionuclide behaviour in PWR primary coolant[D]. Paris: Université de Paris-Sud, 2009. [24] Leuthrot C, Brissaud A, Missud J P. Relationships between the characteristics of cladding defects and the activity of the primary coolant circuit an aid for the management of leaking fuel assemblies in PWR[C]//Proceedings of 1991 International Topical Meeting on Light Water Reactor Fuel Performance. 1991. [25] Beraha R, Beuken G, Frejaville G, et al. Fuel survey in the light water reactors based on the activity of the fission products[J]. Nuclear Technology, 1980, 49(3): 426-434. doi: 10.13182/NT80-A17690 [26] Lewis B J, Chan P K, El-Jaby A, et al. Fission product release modelling for application of fuel-failure monitoring and detection—An overview[J]. Journal of Nuclear Materials, 2017, 489: 64-83. doi: 10.1016/j.jnucmat.2017.03.037 [27] 李兰, 杨洪润. 压水堆核电厂燃料元件破损诊断方法[J]. 核动力工程, 2008, 29(4):135-139Li Lan, Yang Hongrun. Diagnosis method for fuel failures in pressurized water reactor nuclear power plant[J]. Nuclear Power Engineering, 2008, 29(4): 135-139 [28] Neeb K H. The radiochemistry of nuclear power plants with light water reactors[M]. Berlin: Walter de Gruyter, 1997. [29] Lin C C. Radiochemical technology in nuclear power plants[M]. Illinois: American Nuclear Society, 2013. [30] Nagy P, Vajda N, Pintér T, et al. Activities of 134Cs, 135Cs and 137Cs in the primary coolant of VVER-440 reactors[J]. Journal of Radioanalytical and Nuclear Chemistry, 2016, 307(2): 1045-1053. doi: 10.1007/s10967-015-4311-2 [31] Zänker H, Berndt R. Rough localization of defective PWR fuel rods on the basis of the concentration ratio 134Cs/137Cs in the primary coolant[J]. Journal of Radioanalytical and Nuclear Chemistry, 1988, 122(2): 239-244. doi: 10.1007/BF02037766 [32] 梁政强, 王克江, 殷振国, 等. 压水堆核电站破损燃料棒检查进展[J]. 中国原子能科学研究院年报, 2004: 151-152Liang Zhengqiang, Wang Kejiang, Yin Zhenguo, et al. Progress in inspection of fuel defects in pressurized water reactors[J]. Annual Report of China Institute of Atomic Energy, 2004: 151-152 [33] 钱进, 郭一帆, 王鑫, 等. 破损燃料棒二次氢化行为观察与分析[J]. 原子能科学技术, 2020, 54(8):1487-1493 doi: 10.7538/yzk.2019.youxian.0499Qian Jin, Guo Yifan, Wang Xin, et al. Observation and analysis of secondary hydriding behavior of failure fuel rod[J]. Atomic Energy Science and Technology, 2020, 54(8): 1487-1493 doi: 10.7538/yzk.2019.youxian.0499 [34] Ingemansson T, Rudling P, Lundgren K. Assessment of fuel washout in LWRs—new methodologies[C]//Proceedings of the 2004 International Meeting on LWR Fuel Performance. 2004. [35] Sims H E, Dickinson S, Lancaster G, et al. Fission product iodine behaviour in Sizewell B coolant[C]//Proceedings of the International Conference on Water Chemistry of Nuclear Reactor Systems and 8th International Radiolysis, Electrochemistry and Materials Performance Workshop. 2010. [36] Zeh P, Schienbein M, Bleier A, et al. Alpha-nuclides in nuclear power plants[J]. VGB PowerTech, 2008, 88(5): 74-78. [37] 王华才, 程焕林, 宋武林, 等. 压水堆不同燃耗完整和破损棒燃料芯块氧化特征拉曼光谱研究[J]. 强激光与粒子束, 2023, 35:116003 doi: 10.11884/HPLPB202335.230047Wang Huacai, Cheng Huanlin, Song Wulin, et al. Raman characteristic analysis of oxidation of fuel pellets for intact and leaked pressurized water reactors fuel rods with different burnup[J]. High Power Laser and Particle Beams, 2023, 35: 116003 doi: 10.11884/HPLPB202335.230047