The Integrated Aging Management System Applied to Nuclear Power Plants in Korea

Author(s):  
Se-Youl Won ◽  
Kyeong-Soo Lee ◽  
Jae-Gon Lee

According to Post Fukushima action items in Korea, KHNP has established the integrated aging management system to reinforce aging management of system, structures, and components (SSCs) effectively for seven operating units, which are in service for more than twenty years, and for Kori Unit 1 and Wolsung Unit 1, which are subject to continued operation (CO) based on NUREG-1801 GALL report. KHNP’s integrated aging management programs (AMPs) focus on the establishment of aging management system for long-lived operation of nuclear power plants in Korea. The integrated aging management system consists of the integrated AMP standard guideline, operating guideline for each plant, individual AMPs of each plant, and AMP Data Base (DB) system including implementation results, basic DB information related to facilities operating in NPPs, and operating information such as operating experience and evaluation report. The integrated aging management system is importantly utilized for Periodic Safety Review (PSR) and the renewal of CO. Therefore, it will be largely contributed to keep NPPs the level of safety for long time operation through the effective aging management.

Author(s):  
Bruce Geddes ◽  
Ray Torok

The Electric Power Research Institute (EPRI) is conducting research in cooperation with the Nuclear Energy Institute (NEI) regarding Operating Experience of digital Instrumentation and Control (I&C) systems in US nuclear power plants. The primary objective of this work is to extract insights from US nuclear power plant Operating Experience (OE) reports that can be applied to improve Diversity and Defense in Depth (D3) evaluations and methods for protecting nuclear plants against I&C related Common Cause Failures (CCF) that could disable safety functions and thereby degrade plant safety. Between 1987 and 2007, over 500 OE events involving digital equipment in US nuclear power plants were reported through various channels. OE reports for 324 of these events were found in databases maintained by the Nuclear Regulatory Commission (NRC) and the Institute of Nuclear Power Operations (INPO). A database was prepared for capturing the characteristics of each of the 324 events in terms of when, where, how, and why the event occurred, what steps were taken to correct the deficiency that caused the event, and what defensive measures could have been employed to prevent recurrence of these events. The database also captures the plant system type, its safety classification, and whether or not the event involved a common cause failure. This work has revealed the following results and insights: - 82 of the 324 “digital” events did not actually involve a digital failure. Of these 82 non-digital events, 34 might have been prevented by making full use of digital system fault tolerance features. - 242 of the 324 events did involve failures in digital systems. The leading contributors to the 242 digital failures were hardware failure modes. Software change appears as a corrective action twice as often as it appears as an event root cause. This suggests that software features are being added to avoid recurrence of hardware failures, and that adequately designed software is a strong defensive measure against hardware failure modes, preventing them from propagating into system failures and ultimately plant events. 54 of the 242 digital failures involved a Common Cause Failure (CCF). - 13 of the 54 CCF events affected safety (1E) systems, and only 2 of those were due to Inadequate Software Design. This finding suggests that software related CCFs on 1E systems are no more prevalent than other CCF mechanisms for which adherence to various regulations and standards is considered to provide adequate protection against CCF. This research provides an extensive data set that is being used to investigate many different questions related to failure modes, causes, corrective actions, and other event attributes that can be compared and contrasted to reveal useful insights. Specific considerations in this study included comparison of 1E vs. non-1E systems, active vs. potential CCFs, and possible defensive measures to prevent these events. This paper documents the dominant attributes of the evaluated events and the associated insights that can be used to improve methods for protecting against digital I&C related CCFs, applying a test of reasonable assurance.


Environments ◽  
2019 ◽  
Vol 6 (11) ◽  
pp. 120
Author(s):  
Luca Albertone ◽  
Massimo Altavilla ◽  
Manuela Marga ◽  
Laura Porzio ◽  
Giuseppe Tozzi ◽  
...  

Arpa Piemonte has been carrying out, for a long time, controls on clearable materials from nuclear power plants to verify compliance with clearance levels set by ISIN (Ispettorato Nazionale per la Sicurezza Nucleare e la Radioprotezione - National Inspectorate for Nuclear Safety and Radiation Protection) in the technical prescriptions attached to the Ministerial Decree decommissioning authorization or into category A source authorization (higher level of associated risk, according to the categorization defined in the Italian Legislative Decree No. 230/95). After the experience undertaken at the “FN” (Fabbricazioni Nucleari) Bosco Marengo nuclear installation, some controls have been conducted at the Trino nuclear power plant “E. Fermi,” “LivaNova” nuclear installation based in Saluggia, and “EUREX” (Enriched Uranium Extraction) nuclear installation, also based in Saluggia, according to modalities that envisage, as a final control, the determination of γ-emitting radionuclides through in situ gamma spectrometry measurements. Clearance levels’ compliance verification should be performed for all radionuclides potentially present, including those that are not easily measurable (DTM, Difficult To Measure). It is therefore necessary to carry out upstream, based on a representative number of samples, those radionuclides’ determination in order to estimate scaling factors (SF), defined through the logarithmic average of the ratios between the i-th DTM radionuclide concentration and the related key nuclide. Specific radiochemistry is used for defining DTMs’ concentrations, such as Fe-55, Ni-59, Ni-63, Sr-90, Pu-238, and Pu-239/Pu-240. As a key nuclide, Co-60 was chosen for the activation products (Fe-55, Ni-59, Ni-63) and Cs-137 for fission products (Sr-90) and plutonium (Pu- 238, Pu-239/Pu-240, and Pu-241). The presence of very low radioactivity concentrations, often below the detection limits, can make it difficult to determine the related scaling factors. In this work, the results obtained and measurements’ acceptability criteria are presented, defined with ISIN, that can be used for confirming or excluding a radionuclide presence in the process of verifying clearance levels’ compliance. They are also exposed to evaluations regarding samples’ representativeness chosen for scaling factors’ assessment.


2021 ◽  
Author(s):  
A. Protasov ◽  
◽  
A. Sylaieva ◽  
T. Novoselova ◽  
I. Morozovskaya ◽  
...  

Based on many years of research experience of water techno-ecosystems of thermal and nuclear power plants a brief review of the main patterns of formation of the composition, cenotic structure, elements of the functional organization of benthos and periphyton communities was made. It was shown that the composition of zoobenthos and zooperiphyton in some cooling ponds, other technical water bodies and watercourses was quite rich. In addition, due to the rather intensive invasive process, the list of taxa is constantly expanding. Species of tropical and subtropical origin have been recorded. Of particular importance is the invasion of species that may be the cause of bio-hindrances in the operation of power plant equipment. Techno-ecosystems have been studied to varying degrees. One of the most studied for a long time are the cooling ponds of Khmelnitsky and Chernobyl nuclear power plants. Hydrobiological research and monitoring at the first one has been carried out for more than 20 years. It was found that the influence of biotic invasion (invasion of Dreissenidae) may have a significant impact, comparable to extreme technogenic factors, on both the ecosystem and technical water supply facilities. The stages of contourisation and decontourisation processes in the Khmelnitsky NPP techno-ecosystem were established. At the Chernobyl NPP cooling pond, studies were carried out during all periods of the existence of the reservoir and the power plant, until the process of uncontrolled pond descent and transforming it into a unique wetland. Based on the obtained data, practical recommendations relating to the organization of hydrobiological and environmental monitoring, as well as reducing biological hindrances and improving the reliability of power plant equipment have been developed.


Author(s):  
Jun Zhou

Severe weather such as typhoon has long been a great challenge threats the safe operation of nuclear power plants. To cope with typhoon, Qinshan III NPP has developed an effective management system, including building powerful organizations, creating standard response procedures and consumable storage, which proven to be effective to ensure the safe operation of Qinshan III plant under severe weather conditions.


Sign in / Sign up

Export Citation Format

Share Document