Global Radioxenon Emission Inventory from Nuclear Research Reactors

Author(s):  
Martin B. Kalinowski ◽  
Pouneh Tayyebi ◽  
Michael Lechermann ◽  
Halit Tatlisu

AbstractTo monitor compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the International Monitoring System (IMS) is being established which will include 40 sensor systems for atmospheric xenon radioactivity. Radioactive isotopes of the noble gas xenon provide the most likely observable radioactive signatures of underground nuclear explosions. These isotopes are frequently detected by IMS noble gas systems as a result of normal operational releases from different types of nuclear facilities including nuclear power plants (NPPs), medical isotope production facilities (MIPFs), and nuclear research reactors (NRRs). Improved knowledge of the contribution of different emission sources on IMS observations strengthens the screening of radioxenon measurements to exclude observations not relevant to emissions from a nuclear explosion. The contribution of NPPs and MIPFs to the global radioxenon emission inventory is fairly well understood. NRRs have yet to be systematically assessed. This paper is the first attempt to assess the total emission inventory of NRRs expressed as annual total discharges. The results can enhance understanding of those sources most likely to impact IMS background observations and to guide future studies on contributions to IMS station background.

Author(s):  
Martin B. Kalinowski ◽  
Halit Tatlisu

Abstract For the purpose of monitoring for compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the International Monitoring System (IMS) is being established that includes 40 sensor systems for atmospheric xenon radioactivity. Its purpose is to monitor the atmosphere for signatures that may indicate a nuclear explosion. Normal operational releases of radioxenon from nuclear facilities can regularly be observed by these very high-sensitive noble gas systems. Existing best estimates of releases for a generic year are unlikely to apply for any specific year at the level of individual facilities because their releases are highly variable and can change by several orders of magnitude from year to year. In this paper, best knowledge of the radioxenon emission inventory from nuclear power plants (NPPs) is collected for the calendar year 2014. The distribution function for each CTBT relevant radioxenon isotope is derived from all releases from NPPs as reported for 2014. The data of this paper can be used for developing and validating methods based on atmospheric transport modelling that are designed to enhance understanding of the impact of known sources on the IMS background observations.


Author(s):  
Josef Podlaha ◽  
Karel Svoboda ◽  
Eduard Hansli´k

After more than 55 years of activities of the Nuclear Research Institute Rez (NRI) in the nuclear field, there are some obsolete nuclear facilities that shall be decommissioned. NRI is a leading institution in all areas of nuclear R&D in the Czech Republic. NRI has had a dominant position in the nuclear programme since it was established in 1955 as a state-owned research organization and it has developed to its current status. In December 1992, NRI has been transformed into a joint-stock company. The Institute’s activity encompasses nuclear physics, chemistry, nuclear power, experiments at the research reactor and many other topics. Main issues addressed in NRI in the past decades were concentrated on research, development and services provided to the nuclear power plants operating VVER reactors, development of chemical technologies for fuel cycle and irradiation services to research and development in the industrial sector, agriculture, food processing and medicine. The NRI operates two research nuclear reactors, many facilities as a hot cell facility, research laboratories, technology for radioactive waste (RAW) management, radionuclide irradiators, an electron accelerator, etc. The obsolete facilities to be decommissioned comprise various research facilities and facilities for RAW management. Decommissioning of nuclear facilities NRI is the only ongoing decommissioning project in the Czech Republic. Decommissioning started in 2003 and will be finished in 2014. Some facilities have already been successfully decommissioned.


2021 ◽  
Author(s):  
Martin Kalinowski ◽  
Boxue Liu

<p>For the International Monitoring System (IMS) to be effective, it is vital that nuclear explosion signals can be distinguished from natural and man-made radioactivity in the atmosphere. The International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) applies standard event screening criteria, with the objective of characterizing, highlighting, and thereby screening out, events considered to be consistent with natural phenomena or non-nuclear explosive, man-made phenomena. The objective of this study is to apply the kernel density (KD) approach to generate and investigate probability distributions of isotopic ratios for radioxenon releases from certain types of sources. The goal is to create probability density functions that could be applied e.g. with a Bayesian method to determine the probability whether an IMS observation can be explained by known sources or could possibly be caused by a nuclear explosion. KD equations for nuclear facility releases are derived from the data set of the radioxenon emission inventory of all nuclear power plants and all nuclear research reactors, as well as selected medical isotope production facilities in the calendar year 2014. For all types of sources, KD equations will be linked with isotopic ratio calculations that connect the sources and IMS stations as receiver.</p>


Author(s):  
Christian Wallner ◽  
Anna-Maria Rall ◽  
Severin Thummerer

In order to assess the risk of radiological consequences of incidents and accidents in nuclear facilities it is important to contemplate their frequency of occurrence. It has to be shown that incidents and accidents occur sufficiently seldom according to their radiological consequences i. e. the occurrence frequency of radiological doses has to be limited. This is even demanded by the German radiation protection ordinance (StrlSchV), which says that in nuclear facilities other than nuclear power plants (NPP) in operation and for decommissioning, the occurrence frequency of incidents and accidents shall be contemplated in order to prove the design of safety measures and safety installations. Based on the ideas of the ICRP64, we developed a risk based assessment concept for nuclear facilities, which fulfils the requirements of the German regulations concerning dose limits in normal operation and design basis accidents. The general use of the concept is dedicated to nuclear facilities other than nuclear power plants (NPP) in operation and for decommissioning, where the regulation of risk assessment is less sophisticated. The concept specifies occurrence frequency limits for radiation exposure dose ranges, i. e. the occurrence frequency of incidents and accidents has to be limited according to their radiological effects. To apply this concept, scenarios of incidents and accidents are grouped in exposition classes according to their resulting potential effective dose to members of the general public. The occurrence frequencies of the incidents and accidents are summarized in each exposition class whereas the sum must not exceed the frequency limits mentioned above. In the following we introduce the application of this concept in the assessment of the potential radiological consequences of the decommissioning of a nuclear research reactor. We carried out this assessment for the licensing process of the decommissioning on behalf of German authorities.


Author(s):  
Lucien Teunckens

Abstract Belgium started its nuclear programme quite early. The first installations were constructed in the fifties, and presently, more than 55% of the Belgian electricity production is provided by nuclear power plants. After 30 years of nuclear experience, Belgium started the decommissioning of nuclear facilities in the eighties with two main projects: the BR3-PWR plant and the Eurochemic reprocessing plant. The BR3-decommissioning project is carried out at the Belgian Nuclear Research Centre, while the decommissioning of the former Eurochemic reprocessing plant is managed and operated by Belgoprocess n.v., which is also operating the centralised waste treatment facilities and the interim storage for Belgian radioactive waste.


2018 ◽  
Vol 184 (1) ◽  
pp. 98-108
Author(s):  
Sang-Tae Kim ◽  
Jaeryong Yoo

Abstract In this study, the radiation exposure of workers at workplaces registered and licensed between 2008 and 2017 for the production/sale/use of radioactive isotopes (RI) and radioactive generators (RG) was analysed to evaluate the quality of radiation safety management controls in use. The number of facilities using RIs increased by ~26% from 2008 to 2017 whereas the number of facilities using RGs increased by ~166% over the same period. There were 33 029 radiation workers in all fields in 2008, and the number increased by ~32% to 43 467 by 2017. However, the collective effective dose of radiation received by workers decreased in all industries except for those working in nuclear power plants. In other words, the quality of radiation safety management improved over that same time period due to the systematic, continuous introduction of safety mechanisms by the regulatory authority.


Author(s):  
Oleksandr Klevtsov ◽  
Artem Symonov ◽  
Serhii Trubchaninov

The chapter is devoted to the issues of cyber security assessment of instrumentation and control systems (I&C systems) of nuclear power plants (NPP). The authors examined the main types of potential cyber threats at the stages of development and operation of NPP I&C systems. Examples of real incidents at various nuclear facilities caused by intentional cyber-attacks or unintentional computer errors during the maintenance of the software of NPP I&C systems are given. The approaches to vulnerabilities assessment of NPP I&C systems are described. The scope and content of the assessment and periodic reassessment of cyber security of NPP I&C systems are considered. An approach of assessment to cyber security risks is described.


2019 ◽  
Vol 186 (4) ◽  
pp. 524-529
Author(s):  
Si Young Kim

Abstract The intercomparison test is a quality assurance activity performed for internal dose assessment. In Korea, the intercomparison test on internal dose assessment was carried out for nuclear facilities in May 2018. The test involved four nuclear facilities in Korea, and seven exposure scenarios were applied. These scenarios cover the intake of 131I, a uranium mixture, 60Co and tritium under various conditions. This paper only reviews the participant results of three scenarios pertinent to the operation of nuclear power plants and adopts the statistical evaluation method, used in international intercomparison tests, to determine the significance values of the results. Although no outliers were established in the test, improvements in the internal dose assessment procedure were derived. These included the selection of intake time, selection of lung absorption type according to the chemical form and consideration of the contribution of previous intake.


2016 ◽  
Vol 7 (2) ◽  
pp. 42-49
Author(s):  
Nick Shykinov ◽  
Robert Rulko ◽  
Dariusz Mroz

Abstract In the context of energy demands by growing economies, climate changes, fossil fuel pricing volatility, and improved safety and performance of nuclear power plants, many countries express interest in expanding or acquiring nuclear power capacity. In the light of the increased interest in expanding nuclear power the supply chain for nuclear power projects has received more attention in recent years. The importance of the advanced planning of procurement and manufacturing of components of nuclear facilities is critical for these projects. Many of these components are often referred to as long-lead items. They may be equipment, products and systems that are identified to have a delivery time long enough to affect directly the overall timing of a project. In order to avoid negatively affecting the project schedule, these items may need to be sourced out or manufactured years before the beginning of the project. For nuclear facilities, long-lead items include physical components such as large pressure vessels, instrumentation and controls. They may also mean programs and management systems important to the safety of the facility. Authorized nuclear operator training, site evaluation programs, and procurement are some of the examples. The nuclear power industry must often meet very demanding construction and commissioning timelines, and proper advanced planning of the long-lead items helps manage risks to project completion time. For nuclear components there are regulatory and licensing considerations that need to be considered. A national nuclear regulator must be involved early to ensure the components will meet the national legal regulatory requirements. This paper will discuss timing considerations to address the regulatory compliance of nuclear long-lead items.


Author(s):  
Sangmyeon Ahn ◽  
Jungjoon Lee ◽  
Chanwoo Jeong ◽  
Kyungwoo Choi

We are having 23 units of nuclear power plants in operation and 5 units of nuclear power plants under construction in Korea as of September 2012. However, we don’t have any experience on shutdown permanently and decommissioning of nuclear power plants. There are only two research reactors being decommissioned since 1997. It is realized that improvement of the regulatory framework for decommissioning of nuclear facilities has been emphasized constantly from the point of view of IAEA’s safety standards. It is also known that IAEA will prepare the safety requirement on decommissioning of facilities; its title is the Safe Decommissioning of Facilities, General Safety Requirement Part 6. According to the result of IAEA’s Integrated Regulatory Review Service (IRRS) mission to Korea in 2011, it was recommended that the regulatory framework should require decommissioning plans for nuclear installations to be constructed and operated and these plans should be updated periodically. In addition, after the Fukushima nuclear disaster in Japan in March of 2011, preparedness for early decommissioning caused by an unexpected severe accident became important issues and concerns. In this respect, it is acknowledged that the regulatory framework for decommissioning of nuclear facilities in Korea need to be improved. First of all, we focus on identifying the current status and relevant issues of regulatory framework for decommissioning of nuclear power plants compared to the IAEA’s safety standards in order to achieve our goal. And then the plan is established for improvement of regulatory framework for decommissioning of nuclear power plants in Korea. It is expected that if the things will go forward as planned, the revised regulatory framework for decommissioning could enhance the safety regime on the decommissioning of nuclear power plants in Korea in light of international standards.


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