核电厂的老化管理:总结最佳实践的出版物

关于核电厂老化管理国际最佳实践的一份原子能机构新出版物,将支持营运者改进其管理程序,有助于延长反应堆的运行寿期,并为全世界的核安全作出贡献。

2017年4月,国际普遍性老化经验教训机械部件工作组的成员们在匈牙利波克什核电厂的一次会议上。(照片来源:R. Krivanek/原子能机构)

关于核电厂老化管理国际最佳实践的一份原子能机构新出版物,将支持营运者改进其管理程序,有助于延长反应堆的运行寿期,并为全世界的核安全作出贡献。

目前使用中的核动力堆通常设计为运行30年至40年。考虑到建造一座新电厂需要巨大投资,许多营运者和政府都在寻求延长现有设施寿期以实现长期运行的方法。这需要有接受监管监督和经许可证审批的严格老化管理程序。延长核电厂寿期涉及到确定它是否能在原定退役日期之后,继续安全、可靠和成本效益好地运行。当一座电厂的寿期被延长后,其运行通常会再持续20年至40年。

《国际普遍性老化经验教训》(《安全报告丛书》第82号)的最初版本于2015年出版,其中包括了2010年至2014年期间在“国际普遍性老化经验教训”计划内收集的经验。最近出版的《国际普遍性老化经验教训》(《安全报告丛书》第82号Rev.1版)包括了截至2017年的经验,相应网站每年更新一次。

“更多数据和更多经验将带来更多可供世界各地的营运者使用的最佳实践,”原子能机构核装置安全处处长格雷格·仑特考斯基说。“‘国际普遍性老化经验教训’计划能够有效地确定经证明的老化管理计划、时限老化分析和普遍性老化管理审查表,并将其与核能界分享。”

从美国到全世界的老化管理

自2010年发起“国际普遍性老化经验教训”计划以来,原子能机构一直在协调这一领域的国际合作并分享这一领域的最佳实践。该计划既涉及导致结构、系统和部件性能特征退化的物理老化问题,也涉及这些部件的无形老化问题,即缺少零部件、技术支持、供应商和工业能力。

“国际普遍性老化经验教训”计划是以美国的经验为基础的,美国核管理委员会发起了让营运者分享他们在老化管理方面的经验和最佳实践并在此基础上制定准则的进程。这反过来促进了核管理委员会的工作,使核管理委员会在考虑许可证展期时有了一套通用的评价方法。正是这种模式在2010年被原子能机构加以改造后推广到国际范围。自那时起,核管理委员会一直支持这一进程,包括在财政上的支持。

“我们通过参与‘国际普遍性老化经验教训’计划和长期运行安全问题评审工作组访问,能够更好地了解其他国家用于监管长期运行的方法,以及各国电厂实施的老化管理计划,”核管理委员会老化管理许可证展期高级技术顾问、国际普遍性老化经验教训指导委员会主席Allen Hiser说。“在国际上分享运行经验,是在全世界范围内保持知情老化管理的重要组成部分。我们的国际同行们在‘国际普遍性老化经验教训’计划会议上提供的信息,为我们提供了重要的信息来源,我们对其进行评定,并以此对我们的导则进行可能的改进。”

美国电力研究所几十年来一直在进行关于材料老化管理的研究,并且也参与了“国际普遍性老化经验教训”计划,该研究所得出的结论是,“国际普遍性老化经验教训”计划的工作比在美国这方面的工作更为广泛。其2020年6月发布的题为“2020年对美国电力研究所产品在国际原子能机构‘国际普遍性老化经验教训’老化管理计划目录中的产品映射的更新”的报告指出,“国际普遍性老化经验教训”计划的进程超越了美国在“为老化管理计划确定非能动系统、结构和(或)部件”方面的经验,并包括了针对能动设备(如电机、泵和阀门)和没有在美国运行的反应堆类型的特定计划。

“电力研究所认为,在原子能机构‘国际普遍性老化经验教训’计划内进行老化经验教训的国际共享,对于这一领域的进一步改善至关重要。电力研究所通过参加工作组和指导委员会,与原子能机构合作开展了制定‘国际普遍性老化经验教训’计划技术依据的工作,”电力研究所高级技术执行官、同时也是国际普遍性老化经验教训指导委员会成员的Sherry Bernhoft说。“全球各电力公司可能需要根据其国家监管机构的指令实施‘国际普遍性老化经验教训’计划的导则。电力研究所有用的技术信息现已映射到这些老化管理计划,以帮助电力公司实施其老化管理计划。”

“国际普遍性老化经验教训”计划的资金来自参加国的自愿捐款,其中相当大一部分资金来自美国。目前,来自所有30个核电厂运行国的200多名专家正在为该计划作出贡献。

“‘国际普遍性老化经验教训’计划展示了所有30个核电厂运行国监管机构、营运者和研究机构合作的典范。”仑特考斯基说。

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国际普遍性老化经验教训监管监督工作组成员正在参加原子能机构2018年7月在维也纳主办的会议。(照片来源:S. Kunito/原子能机构)

Ageing management from the U.S. to the world

The IAEA has been coordinating international cooperation and the sharing of best practices in this area since 2010, when it launched the IGALL Programme. The Programme deals both with the physical ageing of systems, structures and components, resulting in the degradation of their performance characteristics, and technological obsolescence of such components, i.e. lack of spare parts, technical support, suppliers and industrial capabilities.

IGALL is based on the experience in the United States, where the Nuclear Regulatory Commission (NRC) initiated a process for operators to share their experience and best practices in ageing management and establish guidelines based on these. This in turn facilitated the work of the NRC, which had a common set of approaches to evaluate when considering licensing renewals. It is this model that was adapted and brought to the international scale by the IAEA in 2010. NRC has supported this process, including financially, since.

“Our involvement in IGALL and in Safety Aspect of Long Term Operations (SALTO) review missions have enabled us to better understand the approaches used by other countries to regulate long-term operation and the programmes implemented for ageing management at international plants,” said Allen Hiser, Senior Technical Advisor for License Renewal Aging Management at the NRC, and Chairperson of the IGALL Steering Committee. “International sharing of operating experience is an important part of maintaining informed ageing management worldwide. The information provided by our international counterparts in the IGALL meetings has provided us with an important source of information that we evaluate for potential improvement of our guidance.”

The US-based Electric Power Research Institute (EPRI), which has been performing research on materials ageing management for decades and also participates in IGALL, has concluded that IGALL’s work is broader than what is available in the U.S. Their report, entitled 2020 Update to EPRI Product Mapping to International Atomic Energy Agency (IAEA) International Generic Ageing Lessons Learned (IGALL) Aging Management Program Categories  published in June 2020 states that the IGALL process goes beyond the U.S. experience in  “identifying passive systems, structures, and (or) components for AMPs and includes specific programs for active equipment, such as motors, pumps, and valves and for reactor types that are not operated in the United States.”

“EPRI considers sharing ageing lessons learned internationally within the IAEA IGALL Programme as essential for further improvement in this area. EPRI worked in cooperation with the IAEA on the technical basis for the IGALL by participating on the working groups and Steering Committee,” said Sherry Bernhoft, senior technical executive of EPRI, also IGALL Steering Committee member. “International utilities might need to implement IGALL guidance according to directives from their national regulatory bodies. Useful EPRI technical information is now mapped to those AMPs to assist utilities in implementing AMPs.”

The IGALL programme has been funded by voluntary contributions from participating countries, with substantial part of the funding coming from the United States. Currently, over 200 experts from all 30 countries operating nuclear power plants are contributing to the programme.

“IGALL presents an excellent example of cooperation of regulators, operators and research institutes of all 30 countries operating nuclear power plants,” Rzentkowski said.

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IGALL Working Group 4 'Regulatory Oversight' members participating in a meeting hosted by Agency in Vienna in July 2018. (Photo: S. Kunito/IAEA)